Merge tag 'perf-core-2025-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull performance events updates from Ingo Molnar:
"Core perf code updates:

- Convert mmap() related reference counts to refcount_t. This is in
reaction to the recently fixed refcount bugs, which could have been
detected earlier and could have mitigated the bug somewhat (Thomas
Gleixner, Peter Zijlstra)

- Clean up and simplify the callchain code, in preparation for
sframes (Steven Rostedt, Josh Poimboeuf)

Uprobes updates:

- Add support to optimize usdt probes on x86-64, which gives a
substantial speedup (Jiri Olsa)

- Cleanups and fixes on x86 (Peter Zijlstra)

PMU driver updates:

- Various optimizations and fixes to the Intel PMU driver (Dapeng Mi)

Misc cleanups and fixes:

- Remove redundant __GFP_NOWARN (Qianfeng Rong)"

* tag 'perf-core-2025-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (57 commits)
selftests/bpf: Fix uprobe_sigill test for uprobe syscall error value
uprobes/x86: Return error from uprobe syscall when not called from trampoline
perf: Skip user unwind if the task is a kernel thread
perf: Simplify get_perf_callchain() user logic
perf: Use current->flags & PF_KTHREAD|PF_USER_WORKER instead of current->mm == NULL
perf: Have get_perf_callchain() return NULL if crosstask and user are set
perf: Remove get_perf_callchain() init_nr argument
perf/x86: Print PMU counters bitmap in x86_pmu_show_pmu_cap()
perf/x86/intel: Add ICL_FIXED_0_ADAPTIVE bit into INTEL_FIXED_BITS_MASK
perf/x86/intel: Change macro GLOBAL_CTRL_EN_PERF_METRICS to BIT_ULL(48)
perf/x86: Add PERF_CAP_PEBS_TIMING_INFO flag
perf/x86/intel: Fix IA32_PMC_x_CFG_B MSRs access error
perf/x86/intel: Use early_initcall() to hook bts_init()
uprobes: Remove redundant __GFP_NOWARN
selftests/seccomp: validate uprobe syscall passes through seccomp
seccomp: passthrough uprobe systemcall without filtering
selftests/bpf: Fix uprobe syscall shadow stack test
selftests/bpf: Change test_uretprobe_regs_change for uprobe and uretprobe
selftests/bpf: Add uprobe_regs_equal test
selftests/bpf: Add optimized usdt variant for basic usdt test
...

arch/arm/probes/uprobes/core.c

···
 	     unsigned long vaddr)
 {
 	return uprobe_write_opcode(auprobe, vma, vaddr,
-		   __opcode_to_mem_arm(auprobe->bpinsn));
+		   __opcode_to_mem_arm(auprobe->bpinsn), true);
 }
 
 bool arch_uprobe_ignore(struct arch_uprobe *auprobe, struct pt_regs *regs)

arch/x86/entry/syscalls/syscall_64.tbl

···
 333	common	io_pgetevents		sys_io_pgetevents
 334	common	rseq			sys_rseq
 335	common	uretprobe		sys_uretprobe
+336	common	uprobe			sys_uprobe
 # don't use numbers 387 through 423, add new calls after the last
 # 'common' entry
 424	common	pidfd_send_signal	sys_pidfd_send_signal

arch/x86/events/core.c

···
 
 void x86_pmu_show_pmu_cap(struct pmu *pmu)
 {
-	pr_info("... version:                %d\n",     x86_pmu.version);
-	pr_info("... bit width:              %d\n",     x86_pmu.cntval_bits);
-	pr_info("... generic registers:      %d\n",     x86_pmu_num_counters(pmu));
-	pr_info("... value mask:             %016Lx\n", x86_pmu.cntval_mask);
-	pr_info("... max period:             %016Lx\n", x86_pmu.max_period);
-	pr_info("... fixed-purpose events:   %d\n",     x86_pmu_num_counters_fixed(pmu));
-	pr_info("... event mask:             %016Lx\n", hybrid(pmu, intel_ctrl));
+	pr_info("... version:                   %d\n", x86_pmu.version);
+	pr_info("... bit width:                 %d\n", x86_pmu.cntval_bits);
+	pr_info("... generic counters:          %d\n", x86_pmu_num_counters(pmu));
+	pr_info("... generic bitmap:            %016llx\n", hybrid(pmu, cntr_mask64));
+	pr_info("... fixed-purpose counters:    %d\n", x86_pmu_num_counters_fixed(pmu));
+	pr_info("... fixed-purpose bitmap:      %016llx\n", hybrid(pmu, fixed_cntr_mask64));
+	pr_info("... value mask:                %016llx\n", x86_pmu.cntval_mask);
+	pr_info("... max period:                %016llx\n", x86_pmu.max_period);
+	pr_info("... global_ctrl mask:          %016llx\n", hybrid(pmu, intel_ctrl));
 }
 
 static int __init init_hw_perf_events(void)

arch/x86/events/intel/bts.c

···
 
 	return perf_pmu_register(&bts_pmu, "intel_bts", -1);
 }
-arch_initcall(bts_init);
+early_initcall(bts_init);

arch/x86/events/intel/core.c

···
 {
 	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
 	struct hw_perf_event *hwc = &event->hw;
-	u64 mask, bits = 0;
 	int idx = hwc->idx;
+	u64 bits = 0;
 
 	if (is_topdown_idx(idx)) {
 		struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
···
 
 	idx -= INTEL_PMC_IDX_FIXED;
 	bits = intel_fixed_bits_by_idx(idx, bits);
-	mask = intel_fixed_bits_by_idx(idx, INTEL_FIXED_BITS_MASK);
-
-	if (x86_pmu.intel_cap.pebs_baseline && event->attr.precise_ip) {
+	if (x86_pmu.intel_cap.pebs_baseline && event->attr.precise_ip)
 		bits |= intel_fixed_bits_by_idx(idx, ICL_FIXED_0_ADAPTIVE);
-		mask |= intel_fixed_bits_by_idx(idx, ICL_FIXED_0_ADAPTIVE);
-	}
 
-	cpuc->fixed_ctrl_val &= ~mask;
+	cpuc->fixed_ctrl_val &= ~intel_fixed_bits_by_idx(idx, INTEL_FIXED_BITS_MASK);
 	cpuc->fixed_ctrl_val |= bits;
 }
 
···
 			if (event->group_leader != leader->group_leader)
 				break;
 			for_each_set_bit(idx, (unsigned long *)&event->attr.config2, X86_PMC_IDX_MAX) {
-				if (WARN_ON_ONCE(i + idx > cpuc->n_events))
+				if (i + idx >= cpuc->n_events ||
+				    !is_acr_event_group(cpuc->event_list[i + idx]))
 					return;
 				__set_bit(cpuc->assign[i + idx], (unsigned long *)&event->hw.config1);
 			}
···
 						0, x86_pmu_num_counters(&pmu->pmu), 0, 0);
 
 	if (pmu->intel_cap.perf_metrics)
-		pmu->intel_ctrl |= 1ULL << GLOBAL_CTRL_EN_PERF_METRICS;
+		pmu->intel_ctrl |= GLOBAL_CTRL_EN_PERF_METRICS;
 	else
-		pmu->intel_ctrl &= ~(1ULL << GLOBAL_CTRL_EN_PERF_METRICS);
+		pmu->intel_ctrl &= ~GLOBAL_CTRL_EN_PERF_METRICS;
 
 	intel_pmu_check_event_constraints(pmu->event_constraints,
 					  pmu->cntr_mask64,
···
 		rdmsrq(MSR_IA32_PERF_CAPABILITIES, perf_cap.capabilities);
 		if (!perf_cap.perf_metrics) {
 			x86_pmu.intel_cap.perf_metrics = 0;
-			x86_pmu.intel_ctrl &= ~(1ULL << GLOBAL_CTRL_EN_PERF_METRICS);
+			x86_pmu.intel_ctrl &= ~GLOBAL_CTRL_EN_PERF_METRICS;
 		}
 	}
 
···
 	}
 
 	if (!is_hybrid() && x86_pmu.intel_cap.perf_metrics)
-		x86_pmu.intel_ctrl |= 1ULL << GLOBAL_CTRL_EN_PERF_METRICS;
+		x86_pmu.intel_ctrl |= GLOBAL_CTRL_EN_PERF_METRICS;
 
 	if (x86_pmu.intel_cap.pebs_timing_info)
 		x86_pmu.flags |= PMU_FL_RETIRE_LATENCY;

arch/x86/include/asm/msr-index.h

···
 #define PERF_CAP_PT_IDX			16
 
 #define MSR_PEBS_LD_LAT_THRESHOLD	0x000003f6
-#define PERF_CAP_PEBS_TRAP             BIT_ULL(6)
-#define PERF_CAP_ARCH_REG              BIT_ULL(7)
-#define PERF_CAP_PEBS_FORMAT           0xf00
-#define PERF_CAP_PEBS_BASELINE         BIT_ULL(14)
-#define PERF_CAP_PEBS_MASK	(PERF_CAP_PEBS_TRAP | PERF_CAP_ARCH_REG | \
-				 PERF_CAP_PEBS_FORMAT | PERF_CAP_PEBS_BASELINE)
+#define PERF_CAP_PEBS_TRAP		BIT_ULL(6)
+#define PERF_CAP_ARCH_REG		BIT_ULL(7)
+#define PERF_CAP_PEBS_FORMAT		0xf00
+#define PERF_CAP_PEBS_BASELINE		BIT_ULL(14)
+#define PERF_CAP_PEBS_TIMING_INFO	BIT_ULL(17)
+#define PERF_CAP_PEBS_MASK		(PERF_CAP_PEBS_TRAP | PERF_CAP_ARCH_REG | \
+					 PERF_CAP_PEBS_FORMAT | PERF_CAP_PEBS_BASELINE | \
+					 PERF_CAP_PEBS_TIMING_INFO)
 
 #define MSR_IA32_RTIT_CTL		0x00000570
 #define RTIT_CTL_TRACEEN		BIT(0)

arch/x86/include/asm/perf_event.h

···
 #define ARCH_PERFMON_EVENTSEL_EQ			(1ULL << 36)
 #define ARCH_PERFMON_EVENTSEL_UMASK2			(0xFFULL << 40)
 
-#define INTEL_FIXED_BITS_MASK				0xFULL
 #define INTEL_FIXED_BITS_STRIDE			4
 #define INTEL_FIXED_0_KERNEL				(1ULL << 0)
 #define INTEL_FIXED_0_USER				(1ULL << 1)
···
 #define HSW_IN_TX_CHECKPOINTED				(1ULL << 33)
 #define ICL_EVENTSEL_ADAPTIVE				(1ULL << 34)
 #define ICL_FIXED_0_ADAPTIVE				(1ULL << 32)
+
+#define INTEL_FIXED_BITS_MASK					\
+	(INTEL_FIXED_0_KERNEL | INTEL_FIXED_0_USER |		\
+	 INTEL_FIXED_0_ANYTHREAD | INTEL_FIXED_0_ENABLE_PMI |	\
+	 ICL_FIXED_0_ADAPTIVE)
 
 #define intel_fixed_bits_by_idx(_idx, _bits)			\
 	((_bits) << ((_idx) * INTEL_FIXED_BITS_STRIDE))
···
 #define GLOBAL_STATUS_TRACE_TOPAPMI		BIT_ULL(GLOBAL_STATUS_TRACE_TOPAPMI_BIT)
 #define GLOBAL_STATUS_PERF_METRICS_OVF_BIT	48
 
-#define GLOBAL_CTRL_EN_PERF_METRICS		48
+#define GLOBAL_CTRL_EN_PERF_METRICS		BIT_ULL(48)
 /*
  * We model guest LBR event tracing as another fixed-mode PMC like BTS.
  *

arch/x86/include/asm/shstk.h

···
 int restore_signal_shadow_stack(void);
 int shstk_update_last_frame(unsigned long val);
 bool shstk_is_enabled(void);
+int shstk_pop(u64 *val);
+int shstk_push(u64 val);
 #else
 static inline long shstk_prctl(struct task_struct *task, int option,
 			       unsigned long arg2) { return -EINVAL; }
···
 static inline int restore_signal_shadow_stack(void) { return 0; }
 static inline int shstk_update_last_frame(unsigned long val) { return 0; }
 static inline bool shstk_is_enabled(void) { return false; }
+static inline int shstk_pop(u64 *val) { return -ENOTSUPP; }
+static inline int shstk_push(u64 val) { return -ENOTSUPP; }
 #endif /* CONFIG_X86_USER_SHADOW_STACK */
 
 #endif /* __ASSEMBLER__ */

arch/x86/include/asm/uprobes.h

···
 #define UPROBE_SWBP_INSN		0xcc
 #define UPROBE_SWBP_INSN_SIZE		   1
 
+enum {
+	ARCH_UPROBE_FLAG_CAN_OPTIMIZE   = 0,
+	ARCH_UPROBE_FLAG_OPTIMIZE_FAIL  = 1,
+};
+
 struct uprobe_xol_ops;
 
 struct arch_uprobe {
···
 			u8	ilen;
 		}			push;
 	};
+
+	unsigned long flags;
 };
 
 struct arch_uprobe_task {

arch/x86/kernel/shstk.c

···
 	return ssp;
 }
 
+int shstk_pop(u64 *val)
+{
+	int ret = 0;
+	u64 ssp;
+
+	if (!features_enabled(ARCH_SHSTK_SHSTK))
+		return -ENOTSUPP;
+
+	fpregs_lock_and_load();
+
+	rdmsrq(MSR_IA32_PL3_SSP, ssp);
+	if (val && get_user(*val, (__user u64 *)ssp))
+		ret = -EFAULT;
+	else
+		wrmsrq(MSR_IA32_PL3_SSP, ssp + SS_FRAME_SIZE);
+	fpregs_unlock();
+
+	return ret;
+}
+
+int shstk_push(u64 val)
+{
+	u64 ssp;
+	int ret;
+
+	if (!features_enabled(ARCH_SHSTK_SHSTK))
+		return -ENOTSUPP;
+
+	fpregs_lock_and_load();
+
+	rdmsrq(MSR_IA32_PL3_SSP, ssp);
+	ssp -= SS_FRAME_SIZE;
+	ret = write_user_shstk_64((__user void *)ssp, val);
+	if (!ret)
+		wrmsrq(MSR_IA32_PL3_SSP, ssp);
+	fpregs_unlock();
+
+	return ret;
+}
+
 #define SHSTK_DATA_BIT BIT(63)
 
 static int put_shstk_data(u64 __user *addr, u64 data)

arch/x86/kernel/uprobes.c

···
 #include <asm/processor.h>
 #include <asm/insn.h>
 #include <asm/mmu_context.h>
+#include <asm/nops.h>
 
 /* Post-execution fixups. */
 
···
 
 #ifdef CONFIG_X86_64
 
+struct uretprobe_syscall_args {
+	unsigned long r11;
+	unsigned long cx;
+	unsigned long ax;
+};
+
 asm (
 	".pushsection .rodata\n"
 	".global uretprobe_trampoline_entry\n"
 	"uretprobe_trampoline_entry:\n"
-	"pushq %rax\n"
-	"pushq %rcx\n"
-	"pushq %r11\n"
-	"movq $" __stringify(__NR_uretprobe) ", %rax\n"
+	"push %rax\n"
+	"push %rcx\n"
+	"push %r11\n"
+	"mov $" __stringify(__NR_uretprobe) ", %rax\n"
 	"syscall\n"
 	".global uretprobe_syscall_check\n"
 	"uretprobe_syscall_check:\n"
-	"popq %r11\n"
-	"popq %rcx\n"
-
-	/* The uretprobe syscall replaces stored %rax value with final
+	"pop %r11\n"
+	"pop %rcx\n"
+	/*
+	 * The uretprobe syscall replaces stored %rax value with final
 	 * return address, so we don't restore %rax in here and just
 	 * call ret.
 	 */
-	"retq\n"
+	"ret\n"
+	"int3\n"
 	".global uretprobe_trampoline_end\n"
 	"uretprobe_trampoline_end:\n"
 	".popsection\n"
···
 extern u8 uretprobe_trampoline_end[];
 extern u8 uretprobe_syscall_check[];
 
-void *arch_uprobe_trampoline(unsigned long *psize)
+void *arch_uretprobe_trampoline(unsigned long *psize)
 {
 	static uprobe_opcode_t insn = UPROBE_SWBP_INSN;
 	struct pt_regs *regs = task_pt_regs(current);
···
 SYSCALL_DEFINE0(uretprobe)
 {
 	struct pt_regs *regs = task_pt_regs(current);
-	unsigned long err, ip, sp, r11_cx_ax[3], tramp;
+	struct uretprobe_syscall_args args;
+	unsigned long err, ip, sp, tramp;
 
 	/* If there's no trampoline, we are called from wrong place. */
 	tramp = uprobe_get_trampoline_vaddr();
···
 	if (unlikely(regs->ip != trampoline_check_ip(tramp)))
 		goto sigill;
 
-	err = copy_from_user(r11_cx_ax, (void __user *)regs->sp, sizeof(r11_cx_ax));
+	err = copy_from_user(&args, (void __user *)regs->sp, sizeof(args));
 	if (err)
 		goto sigill;
 
 	/* expose the "right" values of r11/cx/ax/sp to uprobe_consumer/s */
-	regs->r11 = r11_cx_ax[0];
-	regs->cx  = r11_cx_ax[1];
-	regs->ax  = r11_cx_ax[2];
-	regs->sp += sizeof(r11_cx_ax);
+	regs->r11 = args.r11;
+	regs->cx  = args.cx;
+	regs->ax  = args.ax;
+	regs->sp += sizeof(args);
 	regs->orig_ax = -1;
 
 	ip = regs->ip;
···
 	 */
 	if (regs->sp != sp || shstk_is_enabled())
 		return regs->ax;
-	regs->sp -= sizeof(r11_cx_ax);
+	regs->sp -= sizeof(args);
 
 	/* for the case uprobe_consumer has changed r11/cx */
-	r11_cx_ax[0] = regs->r11;
-	r11_cx_ax[1] = regs->cx;
+	args.r11 = regs->r11;
+	args.cx  = regs->cx;
 
 	/*
 	 * ax register is passed through as return value, so we can use
 	 * its space on stack for ip value and jump to it through the
 	 * trampoline's ret instruction
 	 */
-	r11_cx_ax[2] = regs->ip;
+	args.ax  = regs->ip;
 	regs->ip = ip;
 
-	err = copy_to_user((void __user *)regs->sp, r11_cx_ax, sizeof(r11_cx_ax));
+	err = copy_to_user((void __user *)regs->sp, &args, sizeof(args));
 	if (err)
 		goto sigill;
 
···
 		*sr = utask->autask.saved_scratch_register;
 	}
 }
+
+static int tramp_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma)
+{
+	return -EPERM;
+}
+
+static struct page *tramp_mapping_pages[2] __ro_after_init;
+
+static struct vm_special_mapping tramp_mapping = {
+	.name   = "[uprobes-trampoline]",
+	.mremap = tramp_mremap,
+	.pages  = tramp_mapping_pages,
+};
+
+struct uprobe_trampoline {
+	struct hlist_node	node;
+	unsigned long		vaddr;
+};
+
+static bool is_reachable_by_call(unsigned long vtramp, unsigned long vaddr)
+{
+	long delta = (long)(vaddr + 5 - vtramp);
+
+	return delta >= INT_MIN && delta <= INT_MAX;
+}
+
+static unsigned long find_nearest_trampoline(unsigned long vaddr)
+{
+	struct vm_unmapped_area_info info = {
+		.length     = PAGE_SIZE,
+		.align_mask = ~PAGE_MASK,
+	};
+	unsigned long low_limit, high_limit;
+	unsigned long low_tramp, high_tramp;
+	unsigned long call_end = vaddr + 5;
+
+	if (check_add_overflow(call_end, INT_MIN, &low_limit))
+		low_limit = PAGE_SIZE;
+
+	high_limit = call_end + INT_MAX;
+
+	/* Search up from the caller address. */
+	info.low_limit = call_end;
+	info.high_limit = min(high_limit, TASK_SIZE);
+	high_tramp = vm_unmapped_area(&info);
+
+	/* Search down from the caller address. */
+	info.low_limit = max(low_limit, PAGE_SIZE);
+	info.high_limit = call_end;
+	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+	low_tramp = vm_unmapped_area(&info);
+
+	if (IS_ERR_VALUE(high_tramp) && IS_ERR_VALUE(low_tramp))
+		return -ENOMEM;
+	if (IS_ERR_VALUE(high_tramp))
+		return low_tramp;
+	if (IS_ERR_VALUE(low_tramp))
+		return high_tramp;
+
+	/* Return address that's closest to the caller address. */
+	if (call_end - low_tramp < high_tramp - call_end)
+		return low_tramp;
+	return high_tramp;
+}
+
+static struct uprobe_trampoline *create_uprobe_trampoline(unsigned long vaddr)
+{
+	struct pt_regs *regs = task_pt_regs(current);
+	struct mm_struct *mm = current->mm;
+	struct uprobe_trampoline *tramp;
+	struct vm_area_struct *vma;
+
+	if (!user_64bit_mode(regs))
+		return NULL;
+
+	vaddr = find_nearest_trampoline(vaddr);
+	if (IS_ERR_VALUE(vaddr))
+		return NULL;
+
+	tramp = kzalloc(sizeof(*tramp), GFP_KERNEL);
+	if (unlikely(!tramp))
+		return NULL;
+
+	tramp->vaddr = vaddr;
+	vma = _install_special_mapping(mm, tramp->vaddr, PAGE_SIZE,
+				VM_READ|VM_EXEC|VM_MAYEXEC|VM_MAYREAD|VM_DONTCOPY|VM_IO,
+				&tramp_mapping);
+	if (IS_ERR(vma)) {
+		kfree(tramp);
+		return NULL;
+	}
+	return tramp;
+}
+
+static struct uprobe_trampoline *get_uprobe_trampoline(unsigned long vaddr, bool *new)
+{
+	struct uprobes_state *state = &current->mm->uprobes_state;
+	struct uprobe_trampoline *tramp = NULL;
+
+	if (vaddr > TASK_SIZE || vaddr < PAGE_SIZE)
+		return NULL;
+
+	hlist_for_each_entry(tramp, &state->head_tramps, node) {
+		if (is_reachable_by_call(tramp->vaddr, vaddr)) {
+			*new = false;
+			return tramp;
+		}
+	}
+
+	tramp = create_uprobe_trampoline(vaddr);
+	if (!tramp)
+		return NULL;
+
+	*new = true;
+	hlist_add_head(&tramp->node, &state->head_tramps);
+	return tramp;
+}
+
+static void destroy_uprobe_trampoline(struct uprobe_trampoline *tramp)
+{
+	/*
+	 * We do not unmap and release uprobe trampoline page itself,
+	 * because there's no easy way to make sure none of the threads
+	 * is still inside the trampoline.
+	 */
+	hlist_del(&tramp->node);
+	kfree(tramp);
+}
+
+void arch_uprobe_init_state(struct mm_struct *mm)
+{
+	INIT_HLIST_HEAD(&mm->uprobes_state.head_tramps);
+}
+
+void arch_uprobe_clear_state(struct mm_struct *mm)
+{
+	struct uprobes_state *state = &mm->uprobes_state;
+	struct uprobe_trampoline *tramp;
+	struct hlist_node *n;
+
+	hlist_for_each_entry_safe(tramp, n, &state->head_tramps, node)
+		destroy_uprobe_trampoline(tramp);
+}
+
+static bool __in_uprobe_trampoline(unsigned long ip)
+{
+	struct vm_area_struct *vma = vma_lookup(current->mm, ip);
+
+	return vma && vma_is_special_mapping(vma, &tramp_mapping);
+}
+
+static bool in_uprobe_trampoline(unsigned long ip)
+{
+	struct mm_struct *mm = current->mm;
+	bool found, retry = true;
+	unsigned int seq;
+
+	rcu_read_lock();
+	if (mmap_lock_speculate_try_begin(mm, &seq)) {
+		found = __in_uprobe_trampoline(ip);
+		retry = mmap_lock_speculate_retry(mm, seq);
+	}
+	rcu_read_unlock();
+
+	if (retry) {
+		mmap_read_lock(mm);
+		found = __in_uprobe_trampoline(ip);
+		mmap_read_unlock(mm);
+	}
+	return found;
+}
+
+/*
+ * See uprobe syscall trampoline; the call to the trampoline will push
+ * the return address on the stack, the trampoline itself then pushes
+ * cx, r11 and ax.
+ */
+struct uprobe_syscall_args {
+	unsigned long ax;
+	unsigned long r11;
+	unsigned long cx;
+	unsigned long retaddr;
+};
+
+SYSCALL_DEFINE0(uprobe)
+{
+	struct pt_regs *regs = task_pt_regs(current);
+	struct uprobe_syscall_args args;
+	unsigned long ip, sp, sret;
+	int err;
+
+	/* Allow execution only from uprobe trampolines. */
+	if (!in_uprobe_trampoline(regs->ip))
+		return -ENXIO;
+
+	err = copy_from_user(&args, (void __user *)regs->sp, sizeof(args));
+	if (err)
+		goto sigill;
+
+	ip = regs->ip;
+
+	/*
+	 * expose the "right" values of ax/r11/cx/ip/sp to uprobe_consumer/s, plus:
+	 * - adjust ip to the probe address, call saved next instruction address
+	 * - adjust sp to the probe's stack frame (check trampoline code)
+	 */
+	regs->ax  = args.ax;
+	regs->r11 = args.r11;
+	regs->cx  = args.cx;
+	regs->ip  = args.retaddr - 5;
+	regs->sp += sizeof(args);
+	regs->orig_ax = -1;
+
+	sp = regs->sp;
+
+	err = shstk_pop((u64 *)&sret);
+	if (err == -EFAULT || (!err && sret != args.retaddr))
+		goto sigill;
+
+	handle_syscall_uprobe(regs, regs->ip);
+
+	/*
+	 * Some of the uprobe consumers has changed sp, we can do nothing,
+	 * just return via iret.
+	 */
+	if (regs->sp != sp) {
+		/* skip the trampoline call */
+		if (args.retaddr - 5 == regs->ip)
+			regs->ip += 5;
+		return regs->ax;
+	}
+
+	regs->sp -= sizeof(args);
+
+	/* for the case uprobe_consumer has changed ax/r11/cx */
+	args.ax  = regs->ax;
+	args.r11 = regs->r11;
+	args.cx  = regs->cx;
+
+	/* keep return address unless we are instructed otherwise */
+	if (args.retaddr - 5 != regs->ip)
+		args.retaddr = regs->ip;
+
+	if (shstk_push(args.retaddr) == -EFAULT)
+		goto sigill;
+
+	regs->ip = ip;
+
+	err = copy_to_user((void __user *)regs->sp, &args, sizeof(args));
+	if (err)
+		goto sigill;
+
+	/* ensure sysret, see do_syscall_64() */
+	regs->r11 = regs->flags;
+	regs->cx  = regs->ip;
+	return 0;
+
+sigill:
+	force_sig(SIGILL);
+	return -1;
+}
+
+asm (
+	".pushsection .rodata\n"
+	".balign " __stringify(PAGE_SIZE) "\n"
+	"uprobe_trampoline_entry:\n"
+	"push %rcx\n"
+	"push %r11\n"
+	"push %rax\n"
+	"mov $" __stringify(__NR_uprobe) ", %rax\n"
+	"syscall\n"
+	"pop %rax\n"
+	"pop %r11\n"
+	"pop %rcx\n"
+	"ret\n"
+	"int3\n"
+	".balign " __stringify(PAGE_SIZE) "\n"
+	".popsection\n"
+);
+
+extern u8 uprobe_trampoline_entry[];
+
+static int __init arch_uprobes_init(void)
+{
+	tramp_mapping_pages[0] = virt_to_page(uprobe_trampoline_entry);
+	return 0;
+}
+
+late_initcall(arch_uprobes_init);
+
+enum {
+	EXPECT_SWBP,
+	EXPECT_CALL,
+};
+
+struct write_opcode_ctx {
+	unsigned long base;
+	int expect;
+};
+
+static int is_call_insn(uprobe_opcode_t *insn)
+{
+	return *insn == CALL_INSN_OPCODE;
+}
+
+/*
+ * Verification callback used by int3_update uprobe_write calls to make sure
+ * the underlying instruction is as expected - either int3 or call.
+ */
+static int verify_insn(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode,
+		       int nbytes, void *data)
+{
+	struct write_opcode_ctx *ctx = data;
+	uprobe_opcode_t old_opcode[5];
+
+	uprobe_copy_from_page(page, ctx->base, (uprobe_opcode_t *) &old_opcode, 5);
+
+	switch (ctx->expect) {
+	case EXPECT_SWBP:
+		if (is_swbp_insn(&old_opcode[0]))
+			return 1;
+		break;
+	case EXPECT_CALL:
+		if (is_call_insn(&old_opcode[0]))
+			return 1;
+		break;
+	}
+
+	return -1;
+}
+
+/*
+ * Modify multi-byte instructions by using INT3 breakpoints on SMP.
+ * We completely avoid using stop_machine() here, and achieve the
+ * synchronization using INT3 breakpoints and SMP cross-calls.
+ * (borrowed comment from smp_text_poke_batch_finish)
+ *
+ * The way it is done:
+ *   - Add an INT3 trap to the address that will be patched
+ *   - SMP sync all CPUs
+ *   - Update all but the first byte of the patched range
+ *   - SMP sync all CPUs
+ *   - Replace the first byte (INT3) by the first byte of the replacing opcode
+ *   - SMP sync all CPUs
+ */
+static int int3_update(struct arch_uprobe *auprobe, struct vm_area_struct *vma,
+		       unsigned long vaddr, char *insn, bool optimize)
+{
+	uprobe_opcode_t int3 = UPROBE_SWBP_INSN;
+	struct write_opcode_ctx ctx = {
+		.base = vaddr,
+	};
+	int err;
+
+	/*
+	 * Write int3 trap.
+	 *
+	 * The swbp_optimize path comes with breakpoint already installed,
+	 * so we can skip this step for optimize == true.
+	 */
+	if (!optimize) {
+		ctx.expect = EXPECT_CALL;
+		err = uprobe_write(auprobe, vma, vaddr, &int3, 1, verify_insn,
+				   true /* is_register */, false /* do_update_ref_ctr */,
+				   &ctx);
+		if (err)
+			return err;
+	}
+
+	smp_text_poke_sync_each_cpu();
+
+	/* Write all but the first byte of the patched range. */
+	ctx.expect = EXPECT_SWBP;
+	err = uprobe_write(auprobe, vma, vaddr + 1, insn + 1, 4, verify_insn,
+			   true /* is_register */, false /* do_update_ref_ctr */,
+			   &ctx);
+	if (err)
+		return err;
+
+	smp_text_poke_sync_each_cpu();
+
+	/*
+	 * Write first byte.
+	 *
+	 * The swbp_unoptimize needs to finish uprobe removal together
+	 * with ref_ctr update, using uprobe_write with proper flags.
+	 */
+	err = uprobe_write(auprobe, vma, vaddr, insn, 1, verify_insn,
+			   optimize /* is_register */, !optimize /* do_update_ref_ctr */,
+			   &ctx);
+	if (err)
+		return err;
+
+	smp_text_poke_sync_each_cpu();
+	return 0;
+}
+
+static int swbp_optimize(struct arch_uprobe *auprobe, struct vm_area_struct *vma,
+			 unsigned long vaddr, unsigned long tramp)
+{
+	u8 call[5];
+
+	__text_gen_insn(call, CALL_INSN_OPCODE, (const void *) vaddr,
+			(const void *) tramp, CALL_INSN_SIZE);
+	return int3_update(auprobe, vma, vaddr, call, true /* optimize */);
+}
+
+static int swbp_unoptimize(struct arch_uprobe *auprobe, struct vm_area_struct *vma,
+			   unsigned long vaddr)
+{
+	return int3_update(auprobe, vma, vaddr, auprobe->insn, false /* optimize */);
+}
+
+static int copy_from_vaddr(struct mm_struct *mm, unsigned long vaddr, void *dst, int len)
+{
+	unsigned int gup_flags = FOLL_FORCE|FOLL_SPLIT_PMD;
+	struct vm_area_struct *vma;
+	struct page *page;
+
+	page = get_user_page_vma_remote(mm, vaddr, gup_flags, &vma);
+	if (IS_ERR(page))
+		return PTR_ERR(page);
+	uprobe_copy_from_page(page, vaddr, dst, len);
+	put_page(page);
+	return 0;
+}
+
+static bool __is_optimized(uprobe_opcode_t *insn, unsigned long vaddr)
+{
+	struct __packed __arch_relative_insn {
+		u8 op;
+		s32 raddr;
+	} *call = (struct __arch_relative_insn *) insn;
+
+	if (!is_call_insn(insn))
+		return false;
+	return __in_uprobe_trampoline(vaddr + 5 + call->raddr);
+}
+
+static int is_optimized(struct mm_struct *mm, unsigned long vaddr)
+{
+	uprobe_opcode_t insn[5];
+	int err;
+
+	err = copy_from_vaddr(mm, vaddr, &insn, 5);
+	if (err)
+		return err;
+	return __is_optimized((uprobe_opcode_t *)&insn, vaddr);
+}
+
+static bool should_optimize(struct arch_uprobe *auprobe)
+{
+	return !test_bit(ARCH_UPROBE_FLAG_OPTIMIZE_FAIL, &auprobe->flags) &&
+		test_bit(ARCH_UPROBE_FLAG_CAN_OPTIMIZE, &auprobe->flags);
+}
+
+int set_swbp(struct arch_uprobe *auprobe, struct vm_area_struct *vma,
+	     unsigned long vaddr)
+{
+	if (should_optimize(auprobe)) {
+		/*
+		 * We could race with another thread that already optimized the probe,
+		 * so let's not overwrite it with int3 again in this case.
+		 */
+		int ret = is_optimized(vma->vm_mm, vaddr);
+		if (ret < 0)
+			return ret;
+		if (ret)
+			return 0;
+	}
+	return uprobe_write_opcode(auprobe, vma, vaddr, UPROBE_SWBP_INSN,
+				   true /* is_register */);
+}
+
+int set_orig_insn(struct arch_uprobe *auprobe, struct vm_area_struct *vma,
+		  unsigned long vaddr)
+{
+	if (test_bit(ARCH_UPROBE_FLAG_CAN_OPTIMIZE, &auprobe->flags)) {
+		int ret = is_optimized(vma->vm_mm, vaddr);
+		if (ret < 0)
+			return ret;
+		if (ret) {
+			ret = swbp_unoptimize(auprobe, vma, vaddr);
+			WARN_ON_ONCE(ret);
+			return ret;
+		}
+	}
+	return uprobe_write_opcode(auprobe, vma, vaddr, *(uprobe_opcode_t *)&auprobe->insn,
+				   false /* is_register */);
+}
+
+static int __arch_uprobe_optimize(struct arch_uprobe *auprobe, struct mm_struct *mm,
+				  unsigned long vaddr)
+{
+	struct uprobe_trampoline *tramp;
+	struct vm_area_struct *vma;
+	bool new = false;
+	int err = 0;
+
+	vma = find_vma(mm, vaddr);
+	if (!vma)
+		return -EINVAL;
+	tramp = get_uprobe_trampoline(vaddr, &new);
+	if (!tramp)
+		return -EINVAL;
+	err = swbp_optimize(auprobe, vma, vaddr, tramp->vaddr);
+	if (WARN_ON_ONCE(err) && new)
+		destroy_uprobe_trampoline(tramp);
+	return err;
+}
+
+void arch_uprobe_optimize(struct arch_uprobe *auprobe, unsigned long vaddr)
+{
+	struct mm_struct *mm = current->mm;
+	uprobe_opcode_t insn[5];
+
+	if (!should_optimize(auprobe))
+		return;
+
+	mmap_write_lock(mm);
+
+	/*
+	 * Check if some other thread already optimized the uprobe for us,
+	 * if it's the case just go away silently.
+	 */
+	if (copy_from_vaddr(mm, vaddr, &insn, 5))
+		goto unlock;
+	if (!is_swbp_insn((uprobe_opcode_t*) &insn))
+		goto unlock;
+
+	/*
+	 * If we fail to optimize the uprobe we set the fail bit so the
+	 * above should_optimize will fail from now on.
+	 */
+	if (__arch_uprobe_optimize(auprobe, mm, vaddr))
+		set_bit(ARCH_UPROBE_FLAG_OPTIMIZE_FAIL, &auprobe->flags);
+
+unlock:
+	mmap_write_unlock(mm);
+}
+
+static bool insn_is_nop(struct insn *insn)
+{
+	return insn->opcode.nbytes == 1 && insn->opcode.bytes[0] == 0x90;
+}
+
+static bool insn_is_nopl(struct insn *insn)
+{
+	if (insn->opcode.nbytes != 2)
+		return false;
+
+	if (insn->opcode.bytes[0] != 0x0f || insn->opcode.bytes[1] != 0x1f)
+		return false;
+
+	if (!insn->modrm.nbytes)
+		return false;
+
+	if (X86_MODRM_REG(insn->modrm.bytes[0]) != 0)
+		return false;
+
+	/* 0f 1f /0 - NOPL */
+	return true;
+}
+
+static bool can_optimize(struct insn *insn, unsigned long vaddr)
+{
+	if (!insn->x86_64 || insn->length != 5)
+		return false;
+
+	if (!insn_is_nop(insn) && !insn_is_nopl(insn))
+		return false;
+
+	/* We can't do cross page atomic writes yet. */
+	return PAGE_SIZE - (vaddr & ~PAGE_MASK) >= 5;
+}
 #else /* 32-bit: */
 /*
  * No RIP-relative addressing on 32-bit
···
 }
 static void riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
 {
+}
+static bool can_optimize(struct insn *insn, unsigned long vaddr)
+{
+	return false;
 }
 #endif /* CONFIG_X86_64 */
 
···
  */
 int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long addr)
 {
-	struct insn insn;
 	u8 fix_ip_or_call = UPROBE_FIX_IP;
+	struct insn insn;
 	int ret;
 
 	ret = uprobe_init_insn(auprobe, &insn, is_64bit_mm(mm));
 	if (ret)
 		return ret;
+
+	if (can_optimize(&insn, addr))
+		set_bit(ARCH_UPROBE_FLAG_CAN_OPTIMIZE, &auprobe->flags);
 
 	ret = branch_setup_xol_ops(auprobe, &insn);
 	if (ret != -ENOSYS)

arch/x86/kvm/pmu.h

···
 #define MSR_IA32_MISC_ENABLE_PMU_RO_MASK (MSR_IA32_MISC_ENABLE_PEBS_UNAVAIL |	\
 					  MSR_IA32_MISC_ENABLE_BTS_UNAVAIL)
 
-/* retrieve the 4 bits for EN and PMI out of IA32_FIXED_CTR_CTRL */
+/* retrieve a fixed counter bits out of IA32_FIXED_CTR_CTRL */
 #define fixed_ctrl_field(ctrl_reg, idx) \
 	(((ctrl_reg) >> ((idx) * INTEL_FIXED_BITS_STRIDE)) & INTEL_FIXED_BITS_MASK)
 

include/linux/perf_event.h

···
 
 	/* mmap bits */
 	struct mutex			mmap_mutex;
-	atomic_t			mmap_count;
+	refcount_t			mmap_count;
 
 	struct perf_buffer		*rb;
 	struct list_head		rb_entry;
···
 extern void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs);
 extern void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs);
 extern struct perf_callchain_entry *
-get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user,
+get_perf_callchain(struct pt_regs *regs, bool kernel, bool user,
 		   u32 max_stack, bool crosstask, bool add_mark);
 extern int get_callchain_buffers(int max_stack);
 extern void put_callchain_buffers(void);

include/linux/syscalls.h

···
 
 asmlinkage long sys_uretprobe(void);
 
+asmlinkage long sys_uprobe(void);
+
 /* pciconfig: alpha, arm, arm64, ia64, sparc */
 asmlinkage long sys_pciconfig_read(unsigned long bus, unsigned long dfn,
 				unsigned long off, unsigned long len,

include/linux/uprobes.h

···
 #include <linux/wait.h>
 #include <linux/timer.h>
 #include <linux/seqlock.h>
+#include <linux/mutex.h>
 
 struct uprobe;
 struct vm_area_struct;
···
 
 struct uprobes_state {
 	struct xol_area		*xol_area;
+#ifdef CONFIG_X86_64
+	struct hlist_head	head_tramps;
+#endif
 };
+
+typedef int (*uprobe_write_verify_t)(struct page *page, unsigned long vaddr,
+				     uprobe_opcode_t *insn, int nbytes, void *data);
 
 extern void __init uprobes_init(void);
 extern int set_swbp(struct arch_uprobe *aup, struct vm_area_struct *vma, unsigned long vaddr);
···
 extern bool is_trap_insn(uprobe_opcode_t *insn);
 extern unsigned long uprobe_get_swbp_addr(struct pt_regs *regs);
 extern unsigned long uprobe_get_trap_addr(struct pt_regs *regs);
-extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct vm_area_struct *vma, unsigned long vaddr, uprobe_opcode_t);
+extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct vm_area_struct *vma, unsigned long vaddr, uprobe_opcode_t,
+			       bool is_register);
+extern int uprobe_write(struct arch_uprobe *auprobe, struct vm_area_struct *vma, const unsigned long opcode_vaddr,
+			uprobe_opcode_t *insn, int nbytes, uprobe_write_verify_t verify, bool is_register, bool do_update_ref_ctr,
+			void *data);
 extern struct uprobe *uprobe_register(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc);
 extern int uprobe_apply(struct uprobe *uprobe, struct uprobe_consumer *uc, bool);
 extern void uprobe_unregister_nosync(struct uprobe *uprobe, struct uprobe_consumer *uc);
···
 extern void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
 					 void *src, unsigned long len);
 extern void uprobe_handle_trampoline(struct pt_regs *regs);
-extern void *arch_uprobe_trampoline(unsigned long *psize);
+extern void *arch_uretprobe_trampoline(unsigned long *psize);
 extern unsigned long uprobe_get_trampoline_vaddr(void);
+extern void uprobe_copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len);
+extern void arch_uprobe_clear_state(struct mm_struct *mm);
+extern void arch_uprobe_init_state(struct mm_struct *mm);
+extern void handle_syscall_uprobe(struct pt_regs *regs, unsigned long bp_vaddr);
+extern void arch_uprobe_optimize(struct arch_uprobe *auprobe, unsigned long vaddr);
 #else /* !CONFIG_UPROBES */
 struct uprobes_state {
 };

kernel/bpf/stackmap.c

···
 	if (max_depth > sysctl_perf_event_max_stack)
 		max_depth = sysctl_perf_event_max_stack;
 
-	trace = get_perf_callchain(regs, 0, kernel, user, max_depth,
+	trace = get_perf_callchain(regs, kernel, user, max_depth,
 				   false, false);
 
 	if (unlikely(!trace))
···
 	else if (kernel && task)
 		trace = get_callchain_entry_for_task(task, max_depth);
 	else
-		trace = get_perf_callchain(regs, 0, kernel, user, max_depth,
+		trace = get_perf_callchain(regs, kernel, user, max_depth,
 					   crosstask, false);
 
 	if (unlikely(!trace) || trace->nr < skip) {

kernel/events/callchain.c

···
 }
 
 struct perf_callchain_entry *
-get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user,
+get_perf_callchain(struct pt_regs *regs, bool kernel, bool user,
 		   u32 max_stack, bool crosstask, bool add_mark)
 {
 	struct perf_callchain_entry *entry;
 	struct perf_callchain_entry_ctx ctx;
 	int rctx, start_entry_idx;
 
+	/* crosstask is not supported for user stacks */
+	if (crosstask && user && !kernel)
+		return NULL;
+
 	entry = get_callchain_entry(&rctx);
 	if (!entry)
 		return NULL;
 
-	ctx.entry     = entry;
-	ctx.max_stack = max_stack;
-	ctx.nr	      = entry->nr = init_nr;
-	ctx.contexts       = 0;
-	ctx.contexts_maxed = false;
+	ctx.entry		= entry;
+	ctx.max_stack		= max_stack;
+	ctx.nr			= entry->nr = 0;
+	ctx.contexts		= 0;
+	ctx.contexts_maxed	= false;
 
 	if (kernel && !user_mode(regs)) {
 		if (add_mark)
···
 		perf_callchain_kernel(&ctx, regs);
 	}
 
-	if (user) {
+	if (user && !crosstask) {
 		if (!user_mode(regs)) {
-			if  (current->mm)
-				regs = task_pt_regs(current);
-			else
-				regs = NULL;
-		}
-
-		if (regs) {
-			if (crosstask)
+			if (current->flags & (PF_KTHREAD | PF_USER_WORKER))
 				goto exit_put;
-
-			if (add_mark)
-				perf_callchain_store_context(&ctx, PERF_CONTEXT_USER);
-
-			start_entry_idx = entry->nr;
-			perf_callchain_user(&ctx, regs);
-			fixup_uretprobe_trampoline_entries(entry, start_entry_idx);
+			regs = task_pt_regs(current);
 		}
+
+		if (add_mark)
+			perf_callchain_store_context(&ctx, PERF_CONTEXT_USER);
+
+		start_entry_idx = entry->nr;
+		perf_callchain_user(&ctx, regs);
+		fixup_uretprobe_trampoline_entries(entry, start_entry_idx);
 	}
 
 exit_put:

kernel/events/core.c

···
  */
 static inline bool event_update_userpage(struct perf_event *event)
 {
-	if (likely(!atomic_read(&event->mmap_count)))
+	if (likely(!refcount_read(&event->mmap_count)))
 		return false;
 
 	perf_event_update_time(event);
···
 	struct perf_event *event = vma->vm_file->private_data;
 	mapped_f mapped = get_mapped(event, event_mapped);
 
-	atomic_inc(&event->mmap_count);
-	atomic_inc(&event->rb->mmap_count);
+	refcount_inc(&event->mmap_count);
+	refcount_inc(&event->rb->mmap_count);
 
 	if (vma->vm_pgoff)
-		atomic_inc(&event->rb->aux_mmap_count);
+		refcount_inc(&event->rb->aux_mmap_count);
 
 	if (mapped)
 		mapped(event, vma->vm_mm);
···
 	 * to avoid complications.
 	 */
 	if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
-	    atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &rb->aux_mutex)) {
+	    refcount_dec_and_mutex_lock(&rb->aux_mmap_count, &rb->aux_mutex)) {
 		/*
 		 * Stop all AUX events that are writing to this buffer,
 		 * so that we can free its AUX pages and corresponding PMU
···
 		mutex_unlock(&rb->aux_mutex);
 	}
 
-	if (atomic_dec_and_test(&rb->mmap_count))
+	if (refcount_dec_and_test(&rb->mmap_count))
 		detach_rest = true;
 
-	if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
+	if (!refcount_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
 		goto out_put;
 
 	ring_buffer_attach(event, NULL);
···
 	return err;
 }
 
+static bool perf_mmap_calc_limits(struct vm_area_struct *vma, long *user_extra, long *extra)
+{
+	unsigned long user_locked, user_lock_limit, locked, lock_limit;
+	struct user_struct *user = current_user();
+
+	user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
+	/* Increase the limit linearly with more CPUs */
+	user_lock_limit *= num_online_cpus();
+
+	user_locked = atomic_long_read(&user->locked_vm);
+
+	/*
+	 * sysctl_perf_event_mlock may have changed, so that
+	 *     user->locked_vm > user_lock_limit
+	 */
+	if (user_locked > user_lock_limit)
+		user_locked = user_lock_limit;
+	user_locked += *user_extra;
+
+	if (user_locked > user_lock_limit) {
+		/*
+		 * charge locked_vm until it hits user_lock_limit;
+		 * charge the rest from pinned_vm
+		 */
+		*extra = user_locked - user_lock_limit;
+		*user_extra -= *extra;
+	}
+
+	lock_limit = rlimit(RLIMIT_MEMLOCK);
+	lock_limit >>= PAGE_SHIFT;
+	locked = atomic64_read(&vma->vm_mm->pinned_vm) + *extra;
+
+	return locked <= lock_limit || !perf_is_paranoid() || capable(CAP_IPC_LOCK);
+}
+
+static void perf_mmap_account(struct vm_area_struct *vma, long user_extra, long extra)
+{
+	struct user_struct *user = current_user();
+
+	atomic_long_add(user_extra, &user->locked_vm);
+	atomic64_add(extra, &vma->vm_mm->pinned_vm);
+}
+
+static int perf_mmap_rb(struct vm_area_struct *vma, struct perf_event *event,
+			unsigned long nr_pages)
+{
+	long extra = 0, user_extra = nr_pages;
+	struct perf_buffer *rb;
+	int rb_flags = 0;
+
+	nr_pages -= 1;
+
+	/*
+	 * If we have rb pages ensure they're a power-of-two number, so we
+	 * can do bitmasks instead of modulo.
+	 */
+	if (nr_pages != 0 && !is_power_of_2(nr_pages))
+		return -EINVAL;
+
+	WARN_ON_ONCE(event->ctx->parent_ctx);
+
+	if (event->rb) {
+		if (data_page_nr(event->rb) != nr_pages)
+			return -EINVAL;
+
+		if (refcount_inc_not_zero(&event->rb->mmap_count)) {
+			/*
+			 * Success -- managed to mmap() the same buffer
+			 * multiple times.
+			 */
+			perf_mmap_account(vma, user_extra, extra);
+			refcount_inc(&event->mmap_count);
+			return 0;
+		}
+
+		/*
+		 * Raced against perf_mmap_close()'s
+		 * refcount_dec_and_mutex_lock() remove the
+		 * event and continue as if !event->rb
+		 */
+		ring_buffer_attach(event, NULL);
+	}
+
+	if (!perf_mmap_calc_limits(vma, &user_extra, &extra))
+		return -EPERM;
+
+	if (vma->vm_flags & VM_WRITE)
+		rb_flags |= RING_BUFFER_WRITABLE;
+
+	rb = rb_alloc(nr_pages,
+		      event->attr.watermark ? event->attr.wakeup_watermark : 0,
+		      event->cpu, rb_flags);
+
+	if (!rb)
+		return -ENOMEM;
+
+	refcount_set(&rb->mmap_count, 1);
+	rb->mmap_user = get_current_user();
+	rb->mmap_locked = extra;
+
+	ring_buffer_attach(event, rb);
+
+	perf_event_update_time(event);
+	perf_event_init_userpage(event);
+	perf_event_update_userpage(event);
+
+	perf_mmap_account(vma, user_extra, extra);
+	refcount_set(&event->mmap_count, 1);
+
+	return 0;
+}
+
+static int perf_mmap_aux(struct vm_area_struct *vma, struct perf_event *event,
+			 unsigned long nr_pages)
+{
+	long extra = 0, user_extra = nr_pages;
+	u64 aux_offset, aux_size;
+	struct perf_buffer *rb;
+	int ret, rb_flags = 0;
+
+	rb = event->rb;
+	if (!rb)
+		return -EINVAL;
+
+	guard(mutex)(&rb->aux_mutex);
+
+	/*
+	 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
+	 * mapped, all subsequent mappings should have the same size
+	 * and offset. Must be above the normal perf buffer.
+	 */
+	aux_offset = READ_ONCE(rb->user_page->aux_offset);
+	aux_size = READ_ONCE(rb->user_page->aux_size);
+
+	if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
+		return -EINVAL;
+
+	if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
+		return -EINVAL;
+
+	/* already mapped with a different offset */
+	if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
+		return -EINVAL;
+
+	if (aux_size != nr_pages * PAGE_SIZE)
+		return -EINVAL;
+
+	/* already mapped with a different size */
+	if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
+		return -EINVAL;
+
+	if (!is_power_of_2(nr_pages))
+		return -EINVAL;
+
+	if (!refcount_inc_not_zero(&rb->mmap_count))
+		return -EINVAL;
+
+	if (rb_has_aux(rb)) {
+		refcount_inc(&rb->aux_mmap_count);
+
+	} else {
+		if (!perf_mmap_calc_limits(vma, &user_extra, &extra)) {
+			refcount_dec(&rb->mmap_count);
+			return -EPERM;
+		}
+
+		WARN_ON(!rb && event->rb);
+
+		if (vma->vm_flags & VM_WRITE)
+			rb_flags |= RING_BUFFER_WRITABLE;
+
+		ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
+				   event->attr.aux_watermark, rb_flags);
+		if (ret) {
+			refcount_dec(&rb->mmap_count);
+			return ret;
+		}
+
+		refcount_set(&rb->aux_mmap_count, 1);
+		rb->aux_mmap_locked = extra;
+	}
+
+	perf_mmap_account(vma, user_extra, extra);
+	refcount_inc(&event->mmap_count);
+
+	return 0;
+}
+
 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	struct perf_event *event = file->private_data;
-	unsigned long user_locked, user_lock_limit;
-	struct user_struct *user = current_user();
-	struct mutex *aux_mutex = NULL;
-	struct perf_buffer *rb = NULL;
-	unsigned long locked, lock_limit;
-	unsigned long vma_size;
-	unsigned long nr_pages;
-	long user_extra = 0, extra = 0;
-	int ret, flags = 0;
+	unsigned long vma_size, nr_pages;
 	mapped_f mapped;
+	int ret;
 
 	/*
 	 * Don't allow mmap() of inherited per-task counters. This would
···
 	if (vma_size != PAGE_SIZE * nr_pages)
 		return -EINVAL;
 
-	user_extra = nr_pages;
-
-	mutex_lock(&event->mmap_mutex);
-	ret = -EINVAL;
-
-	/*
-	 * This relies on __pmu_detach_event() taking mmap_mutex after marking
-	 * the event REVOKED. Either we observe the state, or __pmu_detach_event()
-	 * will detach the rb created here.
-	 */
-	if (event->state <= PERF_EVENT_STATE_REVOKED) {
-		ret = -ENODEV;
-		goto unlock;
-	}
-
-	if (vma->vm_pgoff == 0) {
-		nr_pages -= 1;
-
+	scoped_guard (mutex, &event->mmap_mutex) {
 		/*
-		 * If we have rb pages ensure they're a power-of-two number, so we
-		 * can do bitmasks instead of modulo.
+		 * This relies on __pmu_detach_event() taking mmap_mutex after marking
+		 * the event REVOKED. Either we observe the state, or __pmu_detach_event()
+		 * will detach the rb created here.
 		 */
-		if (nr_pages != 0 && !is_power_of_2(nr_pages))
-			goto unlock;
+		if (event->state <= PERF_EVENT_STATE_REVOKED)
+			return -ENODEV;
 
-		WARN_ON_ONCE(event->ctx->parent_ctx);
-
-		if (event->rb) {
-			if (data_page_nr(event->rb) != nr_pages)
-				goto unlock;
-
-			if (atomic_inc_not_zero(&event->rb->mmap_count)) {
-				/*
-				 * Success -- managed to mmap() the same buffer
-				 * multiple times.
-				 */
-				ret = 0;
-				/* We need the rb to map pages. */
-				rb = event->rb;
-				goto unlock;
-			}
-
-			/*
-			 * Raced against perf_mmap_close()'s
-			 * atomic_dec_and_mutex_lock() remove the
-			 * event and continue as if !event->rb
-			 */
-			ring_buffer_attach(event, NULL);
-		}
-
-	} else {
-		/*
-		 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
-		 * mapped, all subsequent mappings should have the same size
-		 * and offset. Must be above the normal perf buffer.
-		 */
-		u64 aux_offset, aux_size;
-
-		rb = event->rb;
-		if (!rb)
-			goto aux_unlock;
-
-		aux_mutex = &rb->aux_mutex;
-		mutex_lock(aux_mutex);
-
-		aux_offset = READ_ONCE(rb->user_page->aux_offset);
-		aux_size = READ_ONCE(rb->user_page->aux_size);
-
-		if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
-			goto aux_unlock;
-
-		if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
-			goto aux_unlock;
-
-		/* already mapped with a different offset */
-		if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
-			goto aux_unlock;
-
-		if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
-			goto aux_unlock;
-
-		/* already mapped with a different size */
-		if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
-			goto aux_unlock;
-
-		if (!is_power_of_2(nr_pages))
-			goto aux_unlock;
-
-		if (!atomic_inc_not_zero(&rb->mmap_count))
-			goto aux_unlock;
-
-		if (rb_has_aux(rb)) {
-			atomic_inc(&rb->aux_mmap_count);
-			ret = 0;
-			goto unlock;
-		}
+		if (vma->vm_pgoff == 0)
+			ret = perf_mmap_rb(vma, event, nr_pages);
+		else
+			ret = perf_mmap_aux(vma, event, nr_pages);
+		if (ret)
+			return ret;
 	}
-
-	user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
-
-	/*
-	 * Increase the limit linearly with more CPUs:
-	 */
-	user_lock_limit *= num_online_cpus();
-
-	user_locked = atomic_long_read(&user->locked_vm);
-
-	/*
-	 * sysctl_perf_event_mlock may have changed, so that
-	 *     user->locked_vm > user_lock_limit
-	 */
-	if (user_locked > user_lock_limit)
-		user_locked = user_lock_limit;
-	user_locked += user_extra;
-
-	if (user_locked > user_lock_limit) {
-		/*
-		 * charge locked_vm until it hits user_lock_limit;
-		 * charge the rest from pinned_vm
-		 */
-		extra = user_locked - user_lock_limit;
-		user_extra -= extra;
-	}
-
-	lock_limit = rlimit(RLIMIT_MEMLOCK);
-	lock_limit >>= PAGE_SHIFT;
-	locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
-
-	if ((locked > lock_limit) && perf_is_paranoid() &&
-		!capable(CAP_IPC_LOCK)) {
-		ret = -EPERM;
-		goto unlock;
-	}
-
-	WARN_ON(!rb && event->rb);
-
-	if (vma->vm_flags & VM_WRITE)
-		flags |= RING_BUFFER_WRITABLE;
-
-	if (!rb) {
-		rb = rb_alloc(nr_pages,
-			      event->attr.watermark ? event->attr.wakeup_watermark : 0,
-			      event->cpu, flags);
-
-		if (!rb) {
-			ret = -ENOMEM;
-			goto unlock;
-		}
-
-		atomic_set(&rb->mmap_count, 1);
-		rb->mmap_user = get_current_user();
-		rb->mmap_locked = extra;
-
-		ring_buffer_attach(event, rb);
-
-		perf_event_update_time(event);
-		perf_event_init_userpage(event);
-		perf_event_update_userpage(event);
-		ret = 0;
-	} else {
-		ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
-				   event->attr.aux_watermark, flags);
-		if (!ret) {
-			atomic_set(&rb->aux_mmap_count, 1);
-			rb->aux_mmap_locked = extra;
-		}
-	}
-
-unlock:
-	if (!ret) {
-		atomic_long_add(user_extra, &user->locked_vm);
-		atomic64_add(extra, &vma->vm_mm->pinned_vm);
-
-		atomic_inc(&event->mmap_count);
-	} else if (rb) {
-		/* AUX allocation failed */
-		atomic_dec(&rb->mmap_count);
-	}
-aux_unlock:
-	if (aux_mutex)
-		mutex_unlock(aux_mutex);
-	mutex_unlock(&event->mmap_mutex);
-
-	if (ret)
-		return ret;
 
 	/*
 	 * Since pinned accounting is per vm we cannot allow fork() to copy our
···
 	 * full cleanup in this case and therefore does not invoke
 	 * vmops::close().
 	 */
-	ret = map_range(rb, vma);
+	ret = map_range(event->rb, vma);
 	if (ret)
 		perf_mmap_close(vma);
 
···
 	if (user_mode(regs)) {
 		regs_user->abi = perf_reg_abi(current);
 		regs_user->regs = regs;
-	} else if (!(current->flags & PF_KTHREAD)) {
+	} else if (!(current->flags & (PF_KTHREAD | PF_USER_WORKER))) {
 		perf_get_regs_user(regs_user, regs);
 	} else {
 		regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
···
 		 * Try IRQ-safe get_user_page_fast_only first.
 		 * If failed, leave phys_addr as 0.
 		 */
-		if (current->mm != NULL) {
+		if (!(current->flags & (PF_KTHREAD | PF_USER_WORKER))) {
 			struct page *p;
 
 			pagefault_disable();
···
 perf_callchain(struct perf_event *event, struct pt_regs *regs)
 {
 	bool kernel = !event->attr.exclude_callchain_kernel;
-	bool user   = !event->attr.exclude_callchain_user;
+	bool user   = !event->attr.exclude_callchain_user &&
+		!(current->flags & (PF_KTHREAD | PF_USER_WORKER));
 	/* Disallow cross-task user callchains. */
 	bool crosstask = event->ctx->task && event->ctx->task != current;
 	const u32 max_stack = event->attr.sample_max_stack;
···
 	if (!kernel && !user)
 		return &__empty_callchain;
 
-	callchain = get_perf_callchain(regs, 0, kernel, user,
+	callchain = get_perf_callchain(regs, kernel, user,
 				       max_stack, crosstask, true);
 	return callchain ?: &__empty_callchain;
 }
···
 	mutex_lock_double(&event->mmap_mutex, &output_event->mmap_mutex);
 set:
 	/* Can't redirect output if we've got an active mmap() */
-	if (atomic_read(&event->mmap_count))
+	if (refcount_read(&event->mmap_count))
 		goto unlock;
 
 	if (output_event) {
···
 			goto unlock;
 
 		/* did we race against perf_mmap_close() */
-		if (!atomic_read(&rb->mmap_count)) {
+		if (!refcount_read(&rb->mmap_count)) {
 			ring_buffer_put(rb);
 			goto unlock;
 		}

kernel/events/internal.h

···
 	spinlock_t			event_lock;
 	struct list_head		event_list;
 
-	atomic_t			mmap_count;
+	refcount_t			mmap_count;
 	unsigned long			mmap_locked;
 	struct user_struct		*mmap_user;
 
···
 	unsigned long			aux_pgoff;
 	int				aux_nr_pages;
 	int				aux_overwrite;
-	atomic_t			aux_mmap_count;
+	refcount_t			aux_mmap_count;
 	unsigned long			aux_mmap_locked;
 	void				(*free_aux)(void *);
 	refcount_t			aux_refcount;

kernel/events/ring_buffer.c

···
 	 * the same order, see perf_mmap_close. Otherwise we end up freeing
 	 * aux pages in this path, which is a bug, because in_atomic().
 	 */
-	if (!atomic_read(&rb->aux_mmap_count))
+	if (!refcount_read(&rb->aux_mmap_count))
 		goto err;
 
 	if (!refcount_inc_not_zero(&rb->aux_refcount))

kernel/events/uprobes.c

···
 	return is_swbp_insn(insn);
 }
 
-static void copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len)
+void uprobe_copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len)
 {
 	void *kaddr = kmap_atomic(page);
 	memcpy(dst, kaddr + (vaddr & ~PAGE_MASK), len);
···
 	kunmap_atomic(kaddr);
 }
 
-static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode)
+static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *insn,
+			 int nbytes, void *data)
 {
 	uprobe_opcode_t old_opcode;
 	bool is_swbp;
···
 	 * is a trap variant; uprobes always wins over any other (gdb)
 	 * breakpoint.
 	 */
-	copy_from_page(page, vaddr, &old_opcode, UPROBE_SWBP_INSN_SIZE);
+	uprobe_copy_from_page(page, vaddr, &old_opcode, UPROBE_SWBP_INSN_SIZE);
 	is_swbp = is_swbp_insn(&old_opcode);
 
-	if (is_swbp_insn(new_opcode)) {
+	if (is_swbp_insn(insn)) {
 		if (is_swbp)		/* register: already installed? */
 			return 0;
 	} else {
···
 	return identical;
 }
 
-static int __uprobe_write_opcode(struct vm_area_struct *vma,
+static int __uprobe_write(struct vm_area_struct *vma,
 		struct folio_walk *fw, struct folio *folio,
-		unsigned long opcode_vaddr, uprobe_opcode_t opcode)
+		unsigned long insn_vaddr, uprobe_opcode_t *insn, int nbytes,
+		bool is_register)
 {
-	const unsigned long vaddr = opcode_vaddr & PAGE_MASK;
-	const bool is_register = !!is_swbp_insn(&opcode);
+	const unsigned long vaddr = insn_vaddr & PAGE_MASK;
 	bool pmd_mappable;
 
 	/* For now, we'll only handle PTE-mapped folios. */
···
 	 */
 	flush_cache_page(vma, vaddr, pte_pfn(fw->pte));
 	fw->pte = ptep_clear_flush(vma, vaddr, fw->ptep);
-	copy_to_page(fw->page, opcode_vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
+	copy_to_page(fw->page, insn_vaddr, insn, nbytes);
 
 	/*
 	 * When unregistering, we may only zap a PTE if uffd is disabled and
···
  * @opcode_vaddr: the virtual address to store the opcode.
  * @opcode: opcode to be written at @opcode_vaddr.
  *
- * Called with mm->mmap_lock held for read or write.
+ * Called with mm->mmap_lock held for write.
  * Return 0 (success) or a negative errno.
  */
 int uprobe_write_opcode(struct arch_uprobe *auprobe, struct vm_area_struct *vma,
-		const unsigned long opcode_vaddr, uprobe_opcode_t opcode)
+		const unsigned long opcode_vaddr, uprobe_opcode_t opcode,
+		bool is_register)
 {
-	const unsigned long vaddr = opcode_vaddr & PAGE_MASK;
+	return uprobe_write(auprobe, vma, opcode_vaddr, &opcode, UPROBE_SWBP_INSN_SIZE,
+			    verify_opcode, is_register, true /* do_update_ref_ctr */, NULL);
+}
+
+int uprobe_write(struct arch_uprobe *auprobe, struct vm_area_struct *vma,
+		 const unsigned long insn_vaddr, uprobe_opcode_t *insn, int nbytes,
+		 uprobe_write_verify_t verify, bool is_register, bool do_update_ref_ctr,
+		 void *data)
+{
+	const unsigned long vaddr = insn_vaddr & PAGE_MASK;
 	struct mm_struct *mm = vma->vm_mm;
 	struct uprobe *uprobe;
-	int ret, is_register, ref_ctr_updated = 0;
+	int ret, ref_ctr_updated = 0;
 	unsigned int gup_flags = FOLL_FORCE;
 	struct mmu_notifier_range range;
 	struct folio_walk fw;
 	struct folio *folio;
 	struct page *page;
 
-	is_register = is_swbp_insn(&opcode);
 	uprobe = container_of(auprobe, struct uprobe, arch);
 
 	if (WARN_ON_ONCE(!is_cow_mapping(vma->vm_flags)))
···
 	 * page that we can safely modify. Use FOLL_WRITE to trigger a write
 	 * fault if required. When unregistering, we might be lucky and the
 	 * anon page is already gone. So defer write faults until really
-	 * required. Use FOLL_SPLIT_PMD, because __uprobe_write_opcode()
+	 * required. Use FOLL_SPLIT_PMD, because __uprobe_write()
 	 * cannot deal with PMDs yet.
 	 */
 	if (is_register)
···
 		goto out;
 	folio = page_folio(page);
 
-	ret = verify_opcode(page, opcode_vaddr, &opcode);
+	ret = verify(page, insn_vaddr, insn, nbytes, data);
 	if (ret <= 0) {
 		folio_put(folio);
 		goto out;
 	}
 
 	/* We are going to replace instruction, update ref_ctr. */
-	if (!ref_ctr_updated && uprobe->ref_ctr_offset) {
+	if (do_update_ref_ctr && !ref_ctr_updated && uprobe->ref_ctr_offset) {
 		ret = update_ref_ctr(uprobe, mm, is_register ? 1 : -1);
 		if (ret) {
 			folio_put(folio);
···
 	/* Walk the page tables again, to perform the actual update. */
 	if (folio_walk_start(&fw, vma, vaddr, 0)) {
 		if (fw.page == page)
-			ret = __uprobe_write_opcode(vma, &fw, folio, opcode_vaddr, opcode);
+			ret = __uprobe_write(vma, &fw, folio, insn_vaddr, insn, nbytes, is_register);
 		folio_walk_end(&fw, vma);
 	}
 
···
 
 out:
 	/* Revert back reference counter if instruction update failed. */
-	if (ret < 0 && ref_ctr_updated)
+	if (do_update_ref_ctr && ret < 0 && ref_ctr_updated)
 		update_ref_ctr(uprobe, mm, is_register ? -1 : 1);
 
 	/* try collapse pmd for compound page */
···
 int __weak set_swbp(struct arch_uprobe *auprobe, struct vm_area_struct *vma,
 		unsigned long vaddr)
 {
-	return uprobe_write_opcode(auprobe, vma, vaddr, UPROBE_SWBP_INSN);
+	return uprobe_write_opcode(auprobe, vma, vaddr, UPROBE_SWBP_INSN, true);
 }
 
 /**
···
 		struct vm_area_struct *vma, unsigned long vaddr)
 {
 	return uprobe_write_opcode(auprobe, vma, vaddr,
-			*(uprobe_opcode_t *)&auprobe->insn);
+			*(uprobe_opcode_t *)&auprobe->insn, false);
 }
 
 /* uprobe should have guaranteed positive refcount */
···
 	if (IS_ERR(page))
 		return PTR_ERR(page);
 
-	copy_from_page(page, offset, insn, nbytes);
+	uprobe_copy_from_page(page, offset, insn, nbytes);
 	put_page(page);
 
 	return 0;
···
 			 * reclaim. This is optimistic, no harm done if it fails.
 			 */
 			prev = kmalloc(sizeof(struct map_info),
-					GFP_NOWAIT | __GFP_NOMEMALLOC | __GFP_NOWARN);
+					GFP_NOWAIT | __GFP_NOMEMALLOC);
 			if (prev)
 				prev->next = NULL;
 		}
···
 		return ERR_PTR(-EINVAL);
 
 	/*
-	 * This ensures that copy_from_page(), copy_to_page() and
+	 * This ensures that uprobe_copy_from_page(), copy_to_page() and
 	 * __update_ref_ctr() can't cross page boundary.
 	 */
 	if (!IS_ALIGNED(offset, UPROBE_SWBP_INSN_SIZE))
···
 	struct vm_area_struct *vma;
 	int err = 0;
 
-	mmap_read_lock(mm);
+	mmap_write_lock(mm);
 	for_each_vma(vmi, vma) {
 		unsigned long vaddr;
 		loff_t offset;
···
 		vaddr = offset_to_vaddr(vma, uprobe->offset);
 		err |= remove_breakpoint(uprobe, vma, vaddr);
 	}
-	mmap_read_unlock(mm);
+	mmap_write_unlock(mm);
 
 	return err;
 }
···
 	return ret;
 }
 
-void * __weak arch_uprobe_trampoline(unsigned long *psize)
+void * __weak arch_uretprobe_trampoline(unsigned long *psize)
 {
 	static uprobe_opcode_t insn = UPROBE_SWBP_INSN;
 
···
 	init_waitqueue_head(&area->wq);
 	/* Reserve the 1st slot for get_trampoline_vaddr() */
 	set_bit(0, area->bitmap);
-	insns = arch_uprobe_trampoline(&insns_size);
+	insns = arch_uretprobe_trampoline(&insns_size);
 	arch_uprobe_copy_ixol(area->page, 0, insns, insns_size);
 
 	if (!xol_add_vma(mm, area))
···
 	return area;
 }
 
+void __weak arch_uprobe_clear_state(struct mm_struct *mm)
+{
+}
+
+void __weak arch_uprobe_init_state(struct mm_struct *mm)
+{
+}
+
 /*
  * uprobe_clear_state - Free the area allocated for slots.
  */
···
 	mutex_lock(&delayed_uprobe_lock);
 	delayed_uprobe_remove(NULL, mm);
 	mutex_unlock(&delayed_uprobe_lock);
+
+	arch_uprobe_clear_state(mm);
 
 	if (!area)
 		return;
···
 	if (result < 0)
 		return result;
 
-	copy_from_page(page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
+	uprobe_copy_from_page(page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
 	put_page(page);
  out:
 	/* This needs to return true for any variant of the trap insn */
···
 	return true;
 }
 
+void __weak arch_uprobe_optimize(struct arch_uprobe *auprobe, unsigned long vaddr)
+{
+}
+
 /*
  * Run handler and ask thread to singlestep.
  * Ensure all non-fatal signals cannot interrupt thread while it singlesteps.
···
 
 	handler_chain(uprobe, regs);
 
+	/* Try to optimize after first hit. */
+	arch_uprobe_optimize(&uprobe->arch, bp_vaddr);
+
 	if (arch_uprobe_skip_sstep(&uprobe->arch, regs))
 		goto out;
 
···
 out:
 	/* arch_uprobe_skip_sstep() succeeded, or restart if can't singlestep */
 	rcu_read_unlock_trace();
+}
+
+void handle_syscall_uprobe(struct pt_regs *regs, unsigned long bp_vaddr)
+{
+	struct uprobe *uprobe;
+	int is_swbp;
+
+	guard(rcu_tasks_trace)();
+
+	uprobe = find_active_uprobe_rcu(bp_vaddr, &is_swbp);
+	if (!uprobe)
+		return;
+	if (!get_utask())
+		return;
+	if (arch_uprobe_ignore(&uprobe->arch, regs))
+		return;
+	handler_chain(uprobe, regs);
 }
 
 /*

kernel/fork.c

···
 {
 #ifdef CONFIG_UPROBES
 	mm->uprobes_state.xol_area = NULL;
+	arch_uprobe_init_state(mm);
 #endif
 }
 

kernel/seccomp.c

···
 }
 
 #ifdef SECCOMP_ARCH_NATIVE
+static bool seccomp_uprobe_exception(struct seccomp_data *sd)
+{
+#if defined __NR_uretprobe || defined __NR_uprobe
+#ifdef SECCOMP_ARCH_COMPAT
+	if (sd->arch == SECCOMP_ARCH_NATIVE)
+#endif
+	{
+#ifdef __NR_uretprobe
+		if (sd->nr == __NR_uretprobe)
+			return true;
+#endif
+#ifdef __NR_uprobe
+		if (sd->nr == __NR_uprobe)
+			return true;
+#endif
+	}
+#endif
+	return false;
+}
+
 /**
  * seccomp_is_const_allow - check if filter is constant allow with given data
  * @fprog: The BPF programs
···
 		return false;
 
 	/* Our single exception to filtering. */
-#ifdef __NR_uretprobe
-#ifdef SECCOMP_ARCH_COMPAT
-	if (sd->arch == SECCOMP_ARCH_NATIVE)
-#endif
-		if (sd->nr == __NR_uretprobe)
-			return true;
-#endif
+	if (seccomp_uprobe_exception(sd))
+		return true;
 
 	for (pc = 0; pc < fprog->len; pc++) {
 		struct sock_filter *insn = &fprog->filter[pc];
···
 	__NR_seccomp_read, __NR_seccomp_write, __NR_seccomp_exit, __NR_seccomp_sigreturn,
 #ifdef __NR_uretprobe
 	__NR_uretprobe,
+#endif
+#ifdef __NR_uprobe
+	__NR_uprobe,
 #endif
 	-1, /* negative terminated */
 };

kernel/sys_ni.c

···
 COND_SYSCALL(rseq);
 
 COND_SYSCALL(uretprobe);
+COND_SYSCALL(uprobe);

tools/arch/x86/include/asm/msr-index.h

···
 #define PERF_CAP_PT_IDX			16
 
 #define MSR_PEBS_LD_LAT_THRESHOLD	0x000003f6
-#define PERF_CAP_PEBS_TRAP             BIT_ULL(6)
-#define PERF_CAP_ARCH_REG              BIT_ULL(7)
-#define PERF_CAP_PEBS_FORMAT           0xf00
-#define PERF_CAP_PEBS_BASELINE         BIT_ULL(14)
-#define PERF_CAP_PEBS_MASK	(PERF_CAP_PEBS_TRAP | PERF_CAP_ARCH_REG | \
-				 PERF_CAP_PEBS_FORMAT | PERF_CAP_PEBS_BASELINE)
+#define PERF_CAP_PEBS_TRAP		BIT_ULL(6)
+#define PERF_CAP_ARCH_REG		BIT_ULL(7)
+#define PERF_CAP_PEBS_FORMAT		0xf00
+#define PERF_CAP_PEBS_BASELINE		BIT_ULL(14)
+#define PERF_CAP_PEBS_TIMING_INFO	BIT_ULL(17)
+#define PERF_CAP_PEBS_MASK		(PERF_CAP_PEBS_TRAP | PERF_CAP_ARCH_REG | \
+					 PERF_CAP_PEBS_FORMAT | PERF_CAP_PEBS_BASELINE | \
+					 PERF_CAP_PEBS_TIMING_INFO)
 
 #define MSR_IA32_RTIT_CTL		0x00000570
 #define RTIT_CTL_TRACEEN		BIT(0)

tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c

···
 #include <asm/ptrace.h>
 #include <linux/compiler.h>
 #include <linux/stringify.h>
+#include <linux/kernel.h>
 #include <sys/wait.h>
 #include <sys/syscall.h>
 #include <sys/prctl.h>
 #include <asm/prctl.h>
 #include "uprobe_syscall.skel.h"
 #include "uprobe_syscall_executed.skel.h"
+#include "bpf/libbpf_internal.h"
 
-__naked unsigned long uretprobe_regs_trigger(void)
+#define USDT_NOP .byte 0x0f, 0x1f, 0x44, 0x00, 0x00
+#include "usdt.h"
+
+#pragma GCC diagnostic ignored "-Wattributes"
+
+__attribute__((aligned(16)))
+__nocf_check __weak __naked unsigned long uprobe_regs_trigger(void)
 {
 	asm volatile (
+		".byte 0x0f, 0x1f, 0x44, 0x00, 0x00\n" /* nop5 */
 		"movq $0xdeadbeef, %rax\n"
 		"ret\n"
 	);
 }
 
-__naked void uretprobe_regs(struct pt_regs *before, struct pt_regs *after)
+__naked void uprobe_regs(struct pt_regs *before, struct pt_regs *after)
 {
 	asm volatile (
 		"movq %r15,   0(%rdi)\n"
···
 		"movq   $0, 120(%rdi)\n" /* orig_rax */
 		"movq   $0, 128(%rdi)\n" /* rip      */
 		"movq   $0, 136(%rdi)\n" /* cs       */
+		"pushq %rax\n"
 		"pushf\n"
 		"pop %rax\n"
 		"movq %rax, 144(%rdi)\n" /* eflags   */
+		"pop %rax\n"
 		"movq %rsp, 152(%rdi)\n" /* rsp      */
 		"movq   $0, 160(%rdi)\n" /* ss       */
 
 		/* save 2nd argument */
 		"pushq %rsi\n"
-		"call uretprobe_regs_trigger\n"
+		"call uprobe_regs_trigger\n"
 
 		/* save  return value and load 2nd argument pointer to rax */
 		"pushq %rax\n"
···
 );
 }
 
-static void test_uretprobe_regs_equal(void)
+static void test_uprobe_regs_equal(bool retprobe)
 {
+	LIBBPF_OPTS(bpf_uprobe_opts, opts,
+		.retprobe = retprobe,
+	);
 	struct uprobe_syscall *skel = NULL;
 	struct pt_regs before = {}, after = {};
 	unsigned long *pb = (unsigned long *) &before;
 	unsigned long *pa = (unsigned long *) &after;
 	unsigned long *pp;
+	unsigned long offset;
 	unsigned int i, cnt;
-	int err;
+
+	offset = get_uprobe_offset(&uprobe_regs_trigger);
+	if (!ASSERT_GE(offset, 0, "get_uprobe_offset"))
+		return;
 
 	skel = uprobe_syscall__open_and_load();
 	if (!ASSERT_OK_PTR(skel, "uprobe_syscall__open_and_load"))
 		goto cleanup;
 
-	err = uprobe_syscall__attach(skel);
-	if (!ASSERT_OK(err, "uprobe_syscall__attach"))
+	skel->links.probe = bpf_program__attach_uprobe_opts(skel->progs.probe,
+				0, "/proc/self/exe", offset, &opts);
+	if (!ASSERT_OK_PTR(skel->links.probe, "bpf_program__attach_uprobe_opts"))
 		goto cleanup;
 
-	uretprobe_regs(&before, &after);
+	/* make sure uprobe gets optimized */
+	if (!retprobe)
+		uprobe_regs_trigger();
+
+	uprobe_regs(&before, &after);
 
 	pp = (unsigned long *) &skel->bss->regs;
 	cnt = sizeof(before)/sizeof(*pb);
···
 		unsigned int offset = i * sizeof(unsigned long);
 
 		/*
-		 * Check register before and after uretprobe_regs_trigger call
+		 * Check register before and after uprobe_regs_trigger call
 		 * that triggers the uretprobe.
 		 */
 		switch (offset) {
···
 
 		/*
 		 * Check register seen from bpf program and register after
-		 * uretprobe_regs_trigger call
+		 * uprobe_regs_trigger call (with rax exception, check below).
 		 */
 		switch (offset) {
 		/*
···
 		case offsetof(struct pt_regs, rsp):
 		case offsetof(struct pt_regs, ss):
 			break;
+		/*
+		 * uprobe does not see return value in rax, it needs to see the
+		 * original (before) rax value
+		 */
+		case offsetof(struct pt_regs, rax):
+			if (!retprobe) {
+				ASSERT_EQ(pp[i], pb[i], "uprobe rax prog-before value check");
+				break;
+			}
 		default:
 			if (!ASSERT_EQ(pp[i], pa[i], "register prog-after value check"))
 				fprintf(stdout, "failed register offset %u\n", offset);
···
 	return ret != n ? (int) ret : 0;
 }
 
-static void test_uretprobe_regs_change(void)
+static void test_regs_change(void)
 {
 	struct pt_regs before = {}, after = {};
 	unsigned long *pb = (unsigned long *) &before;
···
 	unsigned long cnt = sizeof(before)/sizeof(*pb);
 	unsigned int i, err, offset;
 
-	offset = get_uprobe_offset(uretprobe_regs_trigger);
+	offset = get_uprobe_offset(uprobe_regs_trigger);
 
 	err = write_bpf_testmod_uprobe(offset);
 	if (!ASSERT_OK(err, "register_uprobe"))
 		return;
 
-	uretprobe_regs(&before, &after);
+	/* make sure uprobe gets optimized */
+	uprobe_regs_trigger();
+
+	uprobe_regs(&before, &after);
 
 	err = write_bpf_testmod_uprobe(0);
 	if (!ASSERT_OK(err, "unregister_uprobe"))
···
 	);
 	struct uprobe_syscall_executed *skel;
 	int pid, status, err, go[2], c = 0;
+	struct bpf_link *link;
 
 	if (!ASSERT_OK(pipe(go), "pipe"))
 		return;
···
 		_exit(0);
 	}
 
-	skel->links.test = bpf_program__attach_uprobe_multi(skel->progs.test, pid,
-							    "/proc/self/exe",
-							    "uretprobe_syscall_call", &opts);
-	if (!ASSERT_OK_PTR(skel->links.test, "bpf_program__attach_uprobe_multi"))
+	skel->bss->pid = pid;
+
+	link = bpf_program__attach_uprobe_multi(skel->progs.test_uretprobe_multi,
+						pid, "/proc/self/exe",
+						"uretprobe_syscall_call", &opts);
+	if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_multi"))
 		goto cleanup;
+	skel->links.test_uretprobe_multi = link;
 
 	/* kick the child */
 	write(go[1], &c, 1);
···
 	uprobe_syscall_executed__destroy(skel);
 	close(go[1]);
 	close(go[0]);
+}
+
+#define TRAMP "[uprobes-trampoline]"
+
+__attribute__((aligned(16)))
+__nocf_check __weak __naked void uprobe_test(void)
+{
+	asm volatile ("					\n"
+		".byte 0x0f, 0x1f, 0x44, 0x00, 0x00	\n"
+		"ret					\n"
+	);
+}
+
+__attribute__((aligned(16)))
+__nocf_check __weak void usdt_test(void)
+{
+	USDT(optimized_uprobe, usdt);
+}
+
+static int find_uprobes_trampoline(void *tramp_addr)
+{
+	void *start, *end;
+	char line[128];
+	int ret = -1;
+	FILE *maps;
+
+	maps = fopen("/proc/self/maps", "r");
+	if (!maps) {
+		fprintf(stderr, "cannot open maps\n");
+		return -1;
+	}
+
+	while (fgets(line, sizeof(line), maps)) {
+		int m = -1;
+
+		/* We care only about private r-x mappings. */
+		if (sscanf(line, "%p-%p r-xp %*x %*x:%*x %*u %n", &start, &end, &m) != 2)
+			continue;
+		if (m < 0)
+			continue;
+		if (!strncmp(&line[m], TRAMP, sizeof(TRAMP)-1) && (start == tramp_addr)) {
+			ret = 0;
+			break;
+		}
+	}
+
+	fclose(maps);
+	return ret;
+}
+
+static unsigned char nop5[5] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 };
+
+static void *find_nop5(void *fn)
+{
+	int i;
+
+	for (i = 0; i < 10; i++) {
+		if (!memcmp(nop5, fn + i, 5))
+			return fn + i;
+	}
+	return NULL;
+}
+
+typedef void (__attribute__((nocf_check)) *trigger_t)(void);
+
+static void *check_attach(struct uprobe_syscall_executed *skel, trigger_t trigger,
+			  void *addr, int executed)
+{
+	struct __arch_relative_insn {
+		__u8 op;
+		__s32 raddr;
+	} __packed *call;
+	void *tramp = NULL;
+
+	/* Uprobe gets optimized after first trigger, so let's press twice. */
+	trigger();
+	trigger();
+
+	/* Make sure bpf program got executed.. */
+	ASSERT_EQ(skel->bss->executed, executed, "executed");
+
+	/* .. and check the trampoline is as expected. */
+	call = (struct __arch_relative_insn *) addr;
+	tramp = (void *) (call + 1) + call->raddr;
+	ASSERT_EQ(call->op, 0xe8, "call");
+	ASSERT_OK(find_uprobes_trampoline(tramp), "uprobes_trampoline");
+
+	return tramp;
+}
+
+static void check_detach(void *addr, void *tramp)
+{
+	/* [uprobes_trampoline] stays after detach */
+	ASSERT_OK(find_uprobes_trampoline(tramp), "uprobes_trampoline");
+	ASSERT_OK(memcmp(addr, nop5, 5), "nop5");
+}
+
+static void check(struct uprobe_syscall_executed *skel, struct bpf_link *link,
+		  trigger_t trigger, void *addr, int executed)
+{
+	void *tramp;
+
+	tramp = check_attach(skel, trigger, addr, executed);
+	bpf_link__destroy(link);
+	check_detach(addr, tramp);
+}
+
+static void test_uprobe_legacy(void)
+{
+	struct uprobe_syscall_executed *skel = NULL;
+	LIBBPF_OPTS(bpf_uprobe_opts, opts,
+		.retprobe = true,
+	);
+	struct bpf_link *link;
+	unsigned long offset;
+
+	offset = get_uprobe_offset(&uprobe_test);
+	if (!ASSERT_GE(offset, 0, "get_uprobe_offset"))
+		goto cleanup;
+
+	/* uprobe */
+	skel = uprobe_syscall_executed__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "uprobe_syscall_executed__open_and_load"))
+		return;
+
+	skel->bss->pid = getpid();
+
+	link = bpf_program__attach_uprobe_opts(skel->progs.test_uprobe,
+				0, "/proc/self/exe", offset, NULL);
+	if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_opts"))
+		goto cleanup;
+
+	check(skel, link, uprobe_test, uprobe_test, 2);
+
+	/* uretprobe */
+	skel->bss->executed = 0;
+
+	link = bpf_program__attach_uprobe_opts(skel->progs.test_uretprobe,
+				0, "/proc/self/exe", offset, &opts);
+	if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_opts"))
+		goto cleanup;
+
+	check(skel, link, uprobe_test, uprobe_test, 2);
+
+cleanup:
+	uprobe_syscall_executed__destroy(skel);
+}
+
+static void test_uprobe_multi(void)
+{
+	struct uprobe_syscall_executed *skel = NULL;
+	LIBBPF_OPTS(bpf_uprobe_multi_opts, opts);
+	struct bpf_link *link;
+	unsigned long offset;
+
+	offset = get_uprobe_offset(&uprobe_test);
+	if (!ASSERT_GE(offset, 0, "get_uprobe_offset"))
+		goto cleanup;
+
+	opts.offsets = &offset;
+	opts.cnt = 1;
+
+	skel = uprobe_syscall_executed__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "uprobe_syscall_executed__open_and_load"))
+		return;
+
+	skel->bss->pid = getpid();
+
+	/* uprobe.multi */
+	link = bpf_program__attach_uprobe_multi(skel->progs.test_uprobe_multi,
+				0, "/proc/self/exe", NULL, &opts);
+	if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_multi"))
+		goto cleanup;
+
+	check(skel, link, uprobe_test, uprobe_test, 2);
+
+	/* uretprobe.multi */
+	skel->bss->executed = 0;
+	opts.retprobe = true;
+	link = bpf_program__attach_uprobe_multi(skel->progs.test_uretprobe_multi,
+				0, "/proc/self/exe", NULL, &opts);
+	if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_multi"))
+		goto cleanup;
+
+	check(skel, link, uprobe_test, uprobe_test, 2);
+
+cleanup:
+	uprobe_syscall_executed__destroy(skel);
+}
+
+static void test_uprobe_session(void)
+{
+	struct uprobe_syscall_executed *skel = NULL;
+	LIBBPF_OPTS(bpf_uprobe_multi_opts, opts,
+		.session = true,
+	);
+	struct bpf_link *link;
+	unsigned long offset;
+
+	offset = get_uprobe_offset(&uprobe_test);
+	if (!ASSERT_GE(offset, 0, "get_uprobe_offset"))
+		goto cleanup;
+
+	opts.offsets = &offset;
+	opts.cnt = 1;
+
+	skel = uprobe_syscall_executed__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "uprobe_syscall_executed__open_and_load"))
+		return;
+
+	skel->bss->pid = getpid();
+
+	link = bpf_program__attach_uprobe_multi(skel->progs.test_uprobe_session,
+				0, "/proc/self/exe", NULL, &opts);
+	if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_multi"))
+		goto cleanup;
+
+	check(skel, link, uprobe_test, uprobe_test, 4);
+
+cleanup:
+	uprobe_syscall_executed__destroy(skel);
+}
+
+static void test_uprobe_usdt(void)
+{
+	struct uprobe_syscall_executed *skel;
+	struct bpf_link *link;
+	void *addr;
+
+	errno = 0;
+	addr = find_nop5(usdt_test);
+	if (!ASSERT_OK_PTR(addr, "find_nop5"))
+		return;
+
+	skel = uprobe_syscall_executed__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "uprobe_syscall_executed__open_and_load"))
+		return;
+
+	skel->bss->pid = getpid();
+
+	link = bpf_program__attach_usdt(skel->progs.test_usdt,
+				-1 /* all PIDs */, "/proc/self/exe",
+				"optimized_uprobe", "usdt", NULL);
+	if (!ASSERT_OK_PTR(link, "bpf_program__attach_usdt"))
+		goto cleanup;
+
+	check(skel, link, usdt_test, addr, 2);
+
+cleanup:
+	uprobe_syscall_executed__destroy(skel);
 }
 
 /*
···
 		return;
 	}
 
-	/* Run all of the uretprobe tests. */
-	test_uretprobe_regs_equal();
-	test_uretprobe_regs_change();
+	/* Run all the tests with shadow stack in place. */
+
+	test_uprobe_regs_equal(false);
+	test_uprobe_regs_equal(true);
 	test_uretprobe_syscall_call();
+
+	test_uprobe_legacy();
+	test_uprobe_multi();
+	test_uprobe_session();
+	test_uprobe_usdt();
+
+	test_regs_change();
 
 	ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK);
 }
+
+static volatile bool race_stop;
+
+static USDT_DEFINE_SEMA(race);
+
+static void *worker_trigger(void *arg)
+{
+	unsigned long rounds = 0;
+
+	while (!race_stop) {
+		uprobe_test();
+		rounds++;
+	}
+
+	printf("tid %d trigger rounds: %lu\n", gettid(), rounds);
+	return NULL;
+}
+
+static void *worker_attach(void *arg)
+{
+	LIBBPF_OPTS(bpf_uprobe_opts, opts);
+	struct uprobe_syscall_executed *skel;
+	unsigned long rounds = 0, offset;
+	const char *sema[2] = {
+		__stringify(USDT_SEMA(race)),
+		NULL,
+	};
+	unsigned long *ref;
+	int err;
+
+	offset = get_uprobe_offset(&uprobe_test);
+	if (!ASSERT_GE(offset, 0, "get_uprobe_offset"))
+		return NULL;
+
+	err = elf_resolve_syms_offsets("/proc/self/exe", 1, (const char **) &sema, &ref, STT_OBJECT);
+	if (!ASSERT_OK(err, "elf_resolve_syms_offsets_sema"))
+		return NULL;
+
+	opts.ref_ctr_offset = *ref;
+
+	skel = uprobe_syscall_executed__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "uprobe_syscall_executed__open_and_load"))
+		return NULL;
+
+	skel->bss->pid = getpid();
+
+	while (!race_stop) {
+		skel->links.test_uprobe = bpf_program__attach_uprobe_opts(skel->progs.test_uprobe,
+					0, "/proc/self/exe", offset, &opts);
+		if (!ASSERT_OK_PTR(skel->links.test_uprobe, "bpf_program__attach_uprobe_opts"))
+			break;
+
+		bpf_link__destroy(skel->links.test_uprobe);
+		skel->links.test_uprobe = NULL;
+		rounds++;
+	}
+
+	printf("tid %d attach rounds: %lu hits: %d\n", gettid(), rounds, skel->bss->executed);
+	uprobe_syscall_executed__destroy(skel);
+	free(ref);
+	return NULL;
+}
+
+static useconds_t race_msec(void)
+{
+	char *env;
+
+	env = getenv("BPF_SELFTESTS_UPROBE_SYSCALL_RACE_MSEC");
+	if (env)
+		return atoi(env);
+
+	/* default duration is 500ms */
+	return 500;
+}
+
+static void test_uprobe_race(void)
+{
+	int err, i, nr_threads;
+	pthread_t *threads;
+
+	nr_threads = libbpf_num_possible_cpus();
+	if (!ASSERT_GT(nr_threads, 0, "libbpf_num_possible_cpus"))
+		return;
+	nr_threads = max(2, nr_threads);
+
+	threads = alloca(sizeof(*threads) * nr_threads);
+	if (!ASSERT_OK_PTR(threads, "malloc"))
+		return;
+
+	for (i = 0; i < nr_threads; i++) {
+		err = pthread_create(&threads[i], NULL, i % 2 ? worker_trigger : worker_attach,
+				     NULL);
+		if (!ASSERT_OK(err, "pthread_create"))
+			goto cleanup;
+	}
+
+	usleep(race_msec() * 1000);
+
+cleanup:
+	race_stop = true;
+	for (nr_threads = i, i = 0; i < nr_threads; i++)
+		pthread_join(threads[i], NULL);
+
+	ASSERT_FALSE(USDT_SEMA_IS_ACTIVE(race), "race_semaphore");
+}
+
+#ifndef __NR_uprobe
+#define __NR_uprobe 336
+#endif
+
+static void test_uprobe_error(void)
+{
+	long err = syscall(__NR_uprobe);
+
+	ASSERT_EQ(err, -1, "error");
+	ASSERT_EQ(errno, ENXIO, "errno");
+}
+
+static void __test_uprobe_syscall(void)
+{
+	if (test__start_subtest("uretprobe_regs_equal"))
+		test_uprobe_regs_equal(true);
+	if (test__start_subtest("uretprobe_syscall_call"))
+		test_uretprobe_syscall_call();
+	if (test__start_subtest("uretprobe_shadow_stack"))
+		test_uretprobe_shadow_stack();
+	if (test__start_subtest("uprobe_legacy"))
+		test_uprobe_legacy();
+	if (test__start_subtest("uprobe_multi"))
+		test_uprobe_multi();
+	if (test__start_subtest("uprobe_session"))
+		test_uprobe_session();
+	if (test__start_subtest("uprobe_usdt"))
+		test_uprobe_usdt();
+	if (test__start_subtest("uprobe_race"))
+		test_uprobe_race();
+	if (test__start_subtest("uprobe_error"))
+		test_uprobe_error();
+	if (test__start_subtest("uprobe_regs_equal"))
+		test_uprobe_regs_equal(false);
+	if (test__start_subtest("regs_change"))
+		test_regs_change();
+}
 #else
-static void test_uretprobe_regs_equal(void)
-{
-	test__skip();
-}
-
-static void test_uretprobe_regs_change(void)
-{
-	test__skip();
-}
-
-static void test_uretprobe_syscall_call(void)
-{
-	test__skip();
-}
-
-static void test_uretprobe_shadow_stack(void)
+static void __test_uprobe_syscall(void)
 {
 	test__skip();
 }
···
 
 void test_uprobe_syscall(void)
 {
-	if (test__start_subtest("uretprobe_regs_equal"))
-		test_uretprobe_regs_equal();
-	if (test__start_subtest("uretprobe_regs_change"))
-		test_uretprobe_regs_change();
-	if (test__start_subtest("uretprobe_syscall_call"))
-		test_uretprobe_syscall_call();
-	if (test__start_subtest("uretprobe_shadow_stack"))
-		test_uretprobe_shadow_stack();
+	__test_uprobe_syscall();
 }

tools/testing/selftests/bpf/prog_tests/usdt.c

···
 	}
 }
 
-static void subtest_basic_usdt(void)
+static void subtest_basic_usdt(bool optimized)
 {
 	LIBBPF_OPTS(bpf_usdt_opts, opts);
 	struct test_usdt *skel;
 	struct test_usdt__bss *bss;
-	int err, i;
+	int err, i, called;
+
+#define TRIGGER(x) ({			\
+	trigger_func(x);		\
+	if (optimized)			\
+		trigger_func(x);	\
+	optimized ? 2 : 1;		\
+	})
 
 	skel = test_usdt__open_and_load();
 	if (!ASSERT_OK_PTR(skel, "skel_open"))
···
 	if (!ASSERT_OK_PTR(skel->links.usdt0, "usdt0_link"))
 		goto cleanup;
 
-	trigger_func(1);
+	called = TRIGGER(1);
 
-	ASSERT_EQ(bss->usdt0_called, 1, "usdt0_called");
-	ASSERT_EQ(bss->usdt3_called, 1, "usdt3_called");
-	ASSERT_EQ(bss->usdt12_called, 1, "usdt12_called");
+	ASSERT_EQ(bss->usdt0_called, called, "usdt0_called");
+	ASSERT_EQ(bss->usdt3_called, called, "usdt3_called");
+	ASSERT_EQ(bss->usdt12_called, called, "usdt12_called");
 
 	ASSERT_EQ(bss->usdt0_cookie, 0xcafedeadbeeffeed, "usdt0_cookie");
 	ASSERT_EQ(bss->usdt0_arg_cnt, 0, "usdt0_arg_cnt");
···
 	 * bpf_program__attach_usdt() handles this properly and attaches to
 	 * all possible places of USDT invocation.
 	 */
-	trigger_func(2);
+	called += TRIGGER(2);
 
-	ASSERT_EQ(bss->usdt0_called, 2, "usdt0_called");
-	ASSERT_EQ(bss->usdt3_called, 2, "usdt3_called");
-	ASSERT_EQ(bss->usdt12_called, 2, "usdt12_called");
+	ASSERT_EQ(bss->usdt0_called, called, "usdt0_called");
+	ASSERT_EQ(bss->usdt3_called, called, "usdt3_called");
+	ASSERT_EQ(bss->usdt12_called, called, "usdt12_called");
 
 	/* only check values that depend on trigger_func()'s input value */
 	ASSERT_EQ(bss->usdt3_args[0], 2, "usdt3_arg1");
···
 	if (!ASSERT_OK_PTR(skel->links.usdt3, "usdt3_reattach"))
 		goto cleanup;
 
-	trigger_func(3);
+	called += TRIGGER(3);
 
-	ASSERT_EQ(bss->usdt3_called, 3, "usdt3_called");
+	ASSERT_EQ(bss->usdt3_called, called, "usdt3_called");
 	/* this time usdt3 has custom cookie */
 	ASSERT_EQ(bss->usdt3_cookie, 0xBADC00C51E, "usdt3_cookie");
 	ASSERT_EQ(bss->usdt3_arg_cnt, 3, "usdt3_arg_cnt");
···
 
 cleanup:
 	test_usdt__destroy(skel);
+#undef TRIGGER
 }
 
 unsigned short test_usdt_100_semaphore SEC(".probes");
···
 void test_usdt(void)
 {
 	if (test__start_subtest("basic"))
-		subtest_basic_usdt();
+		subtest_basic_usdt(false);
+#ifdef __x86_64__
+	if (test__start_subtest("basic_optimized"))
+		subtest_basic_usdt(true);
+#endif
 	if (test__start_subtest("multispec"))
 		subtest_multispec_usdt();
 	if (test__start_subtest("urand_auto_attach"))

tools/testing/selftests/bpf/progs/uprobe_syscall.c

···
 
 char _license[] SEC("license") = "GPL";
 
-SEC("uretprobe//proc/self/exe:uretprobe_regs_trigger")
-int uretprobe(struct pt_regs *ctx)
+SEC("uprobe")
+int probe(struct pt_regs *ctx)
 {
 	__builtin_memcpy(&regs, ctx, sizeof(regs));
 	return 0;

tools/testing/selftests/bpf/progs/uprobe_syscall_executed.c

···
 // SPDX-License-Identifier: GPL-2.0
 #include "vmlinux.h"
 #include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/usdt.bpf.h>
 #include <string.h>
 
 struct pt_regs regs;
···
 char _license[] SEC("license") = "GPL";
 
 int executed = 0;
+int pid;
+
+SEC("uprobe")
+int BPF_UPROBE(test_uprobe)
+{
+	if (bpf_get_current_pid_tgid() >> 32 != pid)
+		return 0;
+
+	executed++;
+	return 0;
+}
+
+SEC("uretprobe")
+int BPF_URETPROBE(test_uretprobe)
+{
+	if (bpf_get_current_pid_tgid() >> 32 != pid)
+		return 0;
+
+	executed++;
+	return 0;
+}
+
+SEC("uprobe.multi")
+int test_uprobe_multi(struct pt_regs *ctx)
+{
+	if (bpf_get_current_pid_tgid() >> 32 != pid)
+		return 0;
+
+	executed++;
+	return 0;
+}
 
 SEC("uretprobe.multi")
-int test(struct pt_regs *regs)
+int test_uretprobe_multi(struct pt_regs *ctx)
 {
-	executed = 1;
+	if (bpf_get_current_pid_tgid() >> 32 != pid)
+		return 0;
+
+	executed++;
+	return 0;
+}
+
+SEC("uprobe.session")
+int test_uprobe_session(struct pt_regs *ctx)
+{
+	if (bpf_get_current_pid_tgid() >> 32 != pid)
+		return 0;
+
+	executed++;
+	return 0;
+}
+
+SEC("usdt")
+int test_usdt(struct pt_regs *ctx)
+{
+	if (bpf_get_current_pid_tgid() >> 32 != pid)
+		return 0;
+
+	executed++;
 	return 0;
 }

tools/testing/selftests/bpf/test_kmods/bpf_testmod.c

···
 #ifdef __x86_64__
 
 static int
+uprobe_handler(struct uprobe_consumer *self, struct pt_regs *regs, __u64 *data)
+{
+	regs->cx = 0x87654321feebdaed;
+	return 0;
+}
+
+static int
 uprobe_ret_handler(struct uprobe_consumer *self, unsigned long func,
 		   struct pt_regs *regs, __u64 *data)
 
 {
 	regs->ax  = 0x12345678deadbeef;
-	regs->cx  = 0x87654321feebdaed;
 	regs->r11 = (u64) -1;
-	return true;
+	return 0;
 }
 
 struct testmod_uprobe {
···
 static DEFINE_MUTEX(testmod_uprobe_mutex);
 
 static struct testmod_uprobe uprobe = {
+	.consumer.handler = uprobe_handler,
 	.consumer.ret_handler = uprobe_ret_handler,
 };
 

tools/testing/selftests/bpf/usdt.h

···
+// SPDX-License-Identifier: BSD-2-Clause
+/*
+ *  This single-header library defines a collection of variadic macros for
+ *  defining and triggering USDTs (User Statically-Defined Tracepoints):
+ *
+ *      - For USDTs without associated semaphore:
+ *          USDT(group, name, args...)
+ *
+ *      - For USDTs with implicit (transparent to the user) semaphore:
+ *          USDT_WITH_SEMA(group, name, args...)
+ *          USDT_IS_ACTIVE(group, name)
+ *
+ *      - For USDTs with explicit (user-defined and provided) semaphore:
+ *          USDT_WITH_EXPLICIT_SEMA(sema, group, name, args...)
+ *          USDT_SEMA_IS_ACTIVE(sema)
+ *
+ *  all of which emit a NOP instruction into the instruction stream, and so
+ *  have *zero* overhead for the surrounding code. USDTs are identified by
+ *  a combination of `group` and `name` identifiers, which is used by external
+ *  tracing tooling (tracers) for identifying exact USDTs of interest.
+ *
+ *  USDTs can have an associated (2-byte) activity counter (USDT semaphore),
+ *  automatically maintained by Linux kernel whenever any correctly written
+ *  BPF-based tracer is attached to the USDT. This USDT semaphore can be used
+ *  to check whether there is a need to do any extra data collection and
+ *  processing for a given USDT (if necessary), and otherwise avoid extra work
+ *  for a common case of USDT not being traced ("active").
+ *
+ *  See documentation for USDT_WITH_SEMA()/USDT_IS_ACTIVE() or
+ *  USDT_WITH_EXPLICIT_SEMA()/USDT_SEMA_IS_ACTIVE() APIs below for details on
+ *  working with USDTs with implicitly or explicitly associated
+ *  USDT semaphores, respectively.
+ *
+ *  There is also some additional data recorded into an auxiliary note
+ *  section. The data in the note section describes the operands, in terms of
+ *  size and location, used by tracing tooling to know where to find USDT
+ *  arguments. Each location is encoded as an assembler operand string.
+ *  Tracing tools (bpftrace and BPF-based tracers, systemtap, etc) insert
+ *  breakpoints on top of the nop, and decode the location operand-strings,
+ *  like an assembler, to find the values being passed.
+ *
+ *  The operand strings are selected by the compiler for each operand.
+ *  They are constrained by inline-assembler codes.The default is:
+ *
+ *  #define USDT_ARG_CONSTRAINT nor
+ *
+ *  This is a good default if the operands tend to be integral and
+ *  moderate in number (smaller than number of registers). In other
+ *  cases, the compiler may report "'asm' requires impossible reload" or
+ *  similar. In this case, consider simplifying the macro call (fewer
+ *  and simpler operands), reduce optimization, or override the default
+ *  constraints string via:
+ *
+ *  #define USDT_ARG_CONSTRAINT g
+ *  #include <usdt.h>
+ *
+ * For some historical description of USDT v3 format (the one used by this
+ * library and generally recognized and assumed by BPF-based tracing tools)
+ * see [0]. The more formal specification can be found at [1]. Additional
+ * argument constraints information can be found at [2].
+ *
+ * Original SystemTap's sys/sdt.h implementation ([3]) was used as a base for
+ * this USDT library implementation. Current implementation differs *a lot* in
+ * terms of exposed user API and general usability, which was the main goal
+ * and focus of the reimplementation work. Nevertheless, underlying recorded
+ * USDT definitions are fully binary compatible and any USDT-based tooling
+ * should work equally well with USDTs defined by either SystemTap's or this
+ * library's USDT implementation.
+ *
+ *   [0] https://ecos.sourceware.org/ml/systemtap/2010-q3/msg00145.html
+ *   [1] https://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation
+ *   [2] https://gcc.gnu.org/onlinedocs/gcc/Constraints.html
+ *   [3] https://sourceware.org/git/?p=systemtap.git;a=blob;f=includes/sys/sdt.h
+ */
+#ifndef __USDT_H
+#define __USDT_H
+
+/*
+ * Changelog:
+ *
+ * 0.1.0
+ * -----
+ * - Initial release
+ */
+#define USDT_MAJOR_VERSION 0
+#define USDT_MINOR_VERSION 1
+#define USDT_PATCH_VERSION 0
+
+/* C++20 and C23 added __VA_OPT__ as a standard replacement for non-standard `##__VA_ARGS__` extension */
+#if (defined(__STDC_VERSION__) && __STDC_VERSION__ > 201710L) || (defined(__cplusplus) && __cplusplus > 201703L)
+#define __usdt_va_opt 1
+#define __usdt_va_args(...) __VA_OPT__(,) __VA_ARGS__
+#else
+#define __usdt_va_args(...) , ##__VA_ARGS__
+#endif
+
+/*
+ * Trigger USDT with `group`:`name` identifier and pass through `args` as its
+ * arguments. Zero arguments are acceptable as well. No USDT semaphore is
+ * associated with this USDT.
+ *
+ * Such "semaphoreless" USDTs are commonly used when there is no extra data
+ * collection or processing needed to collect and prepare USDT arguments and
+ * they are just available in the surrounding code. USDT() macro will just
+ * record their locations in CPU registers or in memory for tracing tooling to
+ * be able to access them, if necessary.
+ */
+#ifdef __usdt_va_opt
+#define USDT(group, name, ...)							\
+	__usdt_probe(group, name, __usdt_sema_none, 0 __VA_OPT__(,) __VA_ARGS__)
+#else
+#define USDT(group, name, ...)							\
+	__usdt_probe(group, name, __usdt_sema_none, 0, ##__VA_ARGS__)
+#endif
+
+/*
+ * Trigger USDT with `group`:`name` identifier and pass through `args` as its
+ * arguments. Zero arguments are acceptable as well. USDT also get an
+ * implicitly-defined associated USDT semaphore, which will be "activated" by
+ * tracing tooling and can be used to check whether USDT is being actively
+ * observed.
+ *
+ * USDTs with semaphore are commonly used when there is a need to perform
+ * additional data collection and processing to prepare USDT arguments, which
+ * otherwise might not be necessary for the rest of application logic. In such
+ * case, USDT semaphore can be used to avoid unnecessary extra work. If USDT
+ * is not traced (which is presumed to be a common situation), the associated
+ * USDT semaphore is "inactive", and so there is no need to waste resources to
+ * prepare USDT arguments. Use USDT_IS_ACTIVE(group, name) to check whether
+ * USDT is "active".
+ *
+ * N.B. There is an inherent (albeit short) gap between checking whether USDT
+ * is active and triggering corresponding USDT, in which external tracer can
+ * be attached to an USDT and activate USDT semaphore after the activity check.
+ * If such a race occurs, tracers might miss one USDT execution. Tracers are
+ * expected to accommodate such possibility and this is expected to not be
+ * a problem for applications and tracers.
+ *
+ * N.B. Implicit USDT semaphore defined by USDT_WITH_SEMA() is contained
+ * within a single executable or shared library and is not shared outside
+ * them. I.e., if you use USDT_WITH_SEMA() with the same USDT group and name
+ * identifier across executable and shared library, it will work and won't
+ * conflict, per se, but will define independent USDT semaphores, one for each
+ * shared library/executable in which USDT_WITH_SEMA(group, name) is used.
+ * That is, if you attach to this USDT in one shared library (or executable),
+ * then only USDT semaphore within that shared library (or executable) will be
+ * updated by the kernel, while other libraries (or executable) will not see
+ * activated USDT semaphore. In short, it's best to use unique USDT group:name
+ * identifiers across different shared libraries (and, equivalently, between
+ * executable and shared library). This is advanced consideration and is
+ * rarely (if ever) seen in practice, but just to avoid surprises this is
+ * called out here. (Static libraries become a part of final executable, once
+ * linked by linker, so the above considerations don't apply to them.)
+ */
+#ifdef __usdt_va_opt
+#define USDT_WITH_SEMA(group, name, ...)					\
+	__usdt_probe(group, name,						\
+		     __usdt_sema_implicit, __usdt_sema_name(group, name)	\
+		     __VA_OPT__(,) __VA_ARGS__)
+#else
+#define USDT_WITH_SEMA(group, name, ...)					\
+	__usdt_probe(group, name,						\
+		     __usdt_sema_implicit, __usdt_sema_name(group, name),	\
+		     ##__VA_ARGS__)
+#endif
+
+struct usdt_sema { volatile unsigned short active; };
+
+/*
+ * Check if USDT with `group`:`name` identifier is "active" (i.e., whether it
+ * is attached to by external tracing tooling and is actively observed).
+ *
+ * This macro can be used to decide whether any additional and potentially
+ * expensive data collection or processing should be done to pass extra
+ * information into the given USDT. It is assumed that USDT is triggered with
+ * USDT_WITH_SEMA() macro which will implicitly define associated USDT
+ * semaphore. (If one needs more control over USDT semaphore, see
+ * USDT_DEFINE_SEMA() and USDT_WITH_EXPLICIT_SEMA() macros below.)
+ *
+ * N.B. Such checks are necessarily racy and speculative. Between checking
+ * whether USDT is active and triggering the USDT itself, tracer can be
+ * detached with no notification. This race should be extremely rare and worst
+ * case should result in one-time wasted extra data collection and processing.
+ */
+#define USDT_IS_ACTIVE(group, name) ({						\
+	extern struct usdt_sema __usdt_sema_name(group, name)			\
+		__usdt_asm_name(__usdt_sema_name(group, name));			\
+	__usdt_sema_implicit(__usdt_sema_name(group, name));			\
+	__usdt_sema_name(group, name).active > 0;				\
+})
+
+/*
+ * APIs for working with user-defined explicit USDT semaphores.
+ *
+ * This is a less commonly used advanced API for use cases in which user needs
+ * an explicit control over (potentially shared across multiple USDTs) USDT
+ * semaphore instance. This can be used when there is a group of logically
+ * related USDTs that all need extra data collection and processing whenever
+ * any of a family of related USDTs are "activated" (i.e., traced). In such
+ * a case, all such related USDTs will be associated with the same shared USDT
+ * semaphore defined with USDT_DEFINE_SEMA() and the USDTs themselves will be
+ * triggered with USDT_WITH_EXPLICIT_SEMA() macros, taking an explicit extra
+ * USDT semaphore identifier as an extra parameter.
+ */
+
+/**
+ * Underlying C global variable name for user-defined USDT semaphore with
+ * `sema` identifier. Could be useful for debugging, but normally shouldn't be
+ * used explicitly.
+ */
+#define USDT_SEMA(sema) __usdt_sema_##sema
+
+/*
+ * Define storage for user-defined USDT semaphore `sema`.
+ *
+ * Should be used only once in non-header source file to let compiler allocate
+ * space for the semaphore variable. Just like with any other global variable.
+ *
+ * This macro can be used anywhere where global variable declaration is
+ * allowed. Just like with global variable definitions, there should be only
+ * one definition of user-defined USDT semaphore with given `sema` identifier,
+ * otherwise compiler or linker will complain about duplicate variable
+ * definition.
+ *
+ * For C++, it is allowed to use USDT_DEFINE_SEMA() both in global namespace
+ * and inside namespaces (including nested namespaces). Just make sure that
+ * USDT_DECLARE_SEMA() is placed within the namespace where this semaphore is
+ * referenced, or any of its parent namespaces, so the C++ language-level
+ * identifier is visible to the code that needs to reference the semaphore.
+ * At the lowest layer, USDT semaphores have global naming and visibility
+ * (they have a corresponding `__usdt_sema_<name>` symbol, which can be linked
+ * against from C or C++ code, if necessary). To keep it simple, putting
+ * USDT_DECLARE_SEMA() declarations into global namespaces is the simplest
+ * no-brainer solution. All these aspects are irrelevant for plain C, because
+ * C doesn't have namespaces and everything is always in the global namespace.
+ *
+ * N.B. Due to USDT metadata being recorded in non-allocatable ELF note
+ * section, it has limitations when it comes to relocations, which, in
+ * practice, means that it's not possible to correctly share USDT semaphores
+ * between main executable and shared libraries, or even between multiple
+ * shared libraries. USDT semaphore has to be contained to individual shared
+ * library or executable to avoid unpleasant surprises with half-working USDT
+ * semaphores. We enforce this by marking semaphore ELF symbols as having
+ * a hidden visibility. This is quite an advanced use case and consideration
+ * and for most users this should have no consequences whatsoever.
+ */
+#define USDT_DEFINE_SEMA(sema)							\
+	struct usdt_sema __usdt_sema_sec USDT_SEMA(sema)			\
+		__usdt_asm_name(USDT_SEMA(sema))				\
+		__attribute__((visibility("hidden"))) = { 0 }
+
+/*
+ * Declare extern reference to user-defined USDT semaphore `sema`.
+ *
+ * Refers to a variable defined in another compilation unit by
+ * USDT_DEFINE_SEMA() and allows to use the same USDT semaphore across
+ * multiple compilation units (i.e., .c and .cpp files).
+ *
+ * See USDT_DEFINE_SEMA() notes above for C++ language usage peculiarities.
+ */
+#define USDT_DECLARE_SEMA(sema)							\
+	extern struct usdt_sema USDT_SEMA(sema) __usdt_asm_name(USDT_SEMA(sema))
+
+/*
+ * Check if user-defined USDT semaphore `sema` is "active" (i.e., whether it
+ * is attached to by external tracing tooling and is actively observed).
+ *
+ * This macro can be used to decide whether any additional and potentially
+ * expensive data collection or processing should be done to pass extra
+ * information into USDT(s) associated with USDT semaphore `sema`.
+ *
+ * N.B. Such checks are necessarily racy. Between checking the state of USDT
+ * semaphore and triggering associated USDT(s), the active tracer might attach
+ * or detach. This race should be extremely rare and worst case should result
+ * in one-time missed USDT event or wasted extra data collection and
+ * processing. USDT-using tracers should be written with this in mind and is
+ * not a concern of the application defining USDTs with associated semaphore.
+ */
+#define USDT_SEMA_IS_ACTIVE(sema) (USDT_SEMA(sema).active > 0)
+
+/*
+ * Invoke USDT specified by `group` and `name` identifiers and associate
+ * explicitly user-defined semaphore `sema` with it. Pass through `args` as
+ * USDT arguments. `args` are optional and zero arguments are acceptable.
+ *
+ * Semaphore is defined with the help of USDT_DEFINE_SEMA() macro and can be
+ * checked whether active with USDT_SEMA_IS_ACTIVE().
+ */
+#ifdef __usdt_va_opt
+#define USDT_WITH_EXPLICIT_SEMA(sema, group, name, ...)				\
+	__usdt_probe(group, name, __usdt_sema_explicit, USDT_SEMA(sema), ##__VA_ARGS__)
+#else
+#define USDT_WITH_EXPLICIT_SEMA(sema, group, name, ...)				\
+	__usdt_probe(group, name, __usdt_sema_explicit, USDT_SEMA(sema) __VA_OPT__(,) __VA_ARGS__)
+#endif
+
+/*
+ * Adjustable implementation aspects
+ */
+#ifndef USDT_ARG_CONSTRAINT
+#if defined __powerpc__
+#define USDT_ARG_CONSTRAINT		nZr
+#elif defined __arm__
+#define USDT_ARG_CONSTRAINT		g
+#elif defined __loongarch__
+#define USDT_ARG_CONSTRAINT		nmr
+#else
+#define USDT_ARG_CONSTRAINT		nor
+#endif
+#endif /* USDT_ARG_CONSTRAINT */
+
+#ifndef USDT_NOP
+#if defined(__ia64__) || defined(__s390__) || defined(__s390x__)
+#define USDT_NOP			nop 0
+#else
+#define USDT_NOP			nop
+#endif
+#endif /* USDT_NOP */
+
+/*
+ * Implementation details
+ */
+/* USDT name for implicitly-defined USDT semaphore, derived from group:name */
+#define __usdt_sema_name(group, name)	__usdt_sema_##group##__##name
+/* ELF section into which USDT semaphores are put */
+#define __usdt_sema_sec			__attribute__((section(".probes")))
+
+#define __usdt_concat(a, b)		a ## b
+#define __usdt_apply(fn, n)		__usdt_concat(fn, n)
+
+#ifndef __usdt_nth
+#define __usdt_nth(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, N, ...) N
+#endif
+
+#ifndef __usdt_narg
+#ifdef __usdt_va_opt
+#define __usdt_narg(...) __usdt_nth(_ __VA_OPT__(,) __VA_ARGS__, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
+#else
+#define __usdt_narg(...) __usdt_nth(_, ##__VA_ARGS__, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
+#endif
+#endif /* __usdt_narg */
+
+#define __usdt_hash			#
+#define __usdt_str_(x)			#x
+#define __usdt_str(x)			__usdt_str_(x)
+
+#ifndef __usdt_asm_name
+#define __usdt_asm_name(name)		__asm__(__usdt_str(name))
+#endif
+
+#define __usdt_asm0()		"\n"
+#define __usdt_asm1(x)		__usdt_str(x) "\n"
+#define __usdt_asm2(x, ...)	__usdt_str(x) "," __usdt_asm1(__VA_ARGS__)
+#define __usdt_asm3(x, ...)	__usdt_str(x) "," __usdt_asm2(__VA_ARGS__)
+#define __usdt_asm4(x, ...)	__usdt_str(x) "," __usdt_asm3(__VA_ARGS__)
+#define __usdt_asm5(x, ...)	__usdt_str(x) "," __usdt_asm4(__VA_ARGS__)
+#define __usdt_asm6(x, ...)	__usdt_str(x) "," __usdt_asm5(__VA_ARGS__)
+#define __usdt_asm7(x, ...)	__usdt_str(x) "," __usdt_asm6(__VA_ARGS__)
+#define __usdt_asm8(x, ...)	__usdt_str(x) "," __usdt_asm7(__VA_ARGS__)
+#define __usdt_asm9(x, ...)	__usdt_str(x) "," __usdt_asm8(__VA_ARGS__)
+#define __usdt_asm10(x, ...)	__usdt_str(x) "," __usdt_asm9(__VA_ARGS__)
+#define __usdt_asm11(x, ...)	__usdt_str(x) "," __usdt_asm10(__VA_ARGS__)
+#define __usdt_asm12(x, ...)	__usdt_str(x) "," __usdt_asm11(__VA_ARGS__)
+#define __usdt_asm(...)		__usdt_apply(__usdt_asm, __usdt_narg(__VA_ARGS__))(__VA_ARGS__)
+
+#ifdef __LP64__
+#define __usdt_asm_addr		.8byte
+#else
+#define __usdt_asm_addr		.4byte
+#endif
+
+#define __usdt_asm_strz_(x)	__usdt_asm1(.asciz #x)
+#define __usdt_asm_strz(x)	__usdt_asm_strz_(x)
+#define __usdt_asm_str_(x)	__usdt_asm1(.ascii #x)
+#define __usdt_asm_str(x)	__usdt_asm_str_(x)
+
+/* "semaphoreless" USDT case */
+#ifndef __usdt_sema_none
+#define __usdt_sema_none(sema)
+#endif
+
+/* implicitly defined __usdt_sema__group__name semaphore (using weak symbols) */
+#ifndef __usdt_sema_implicit
+#define __usdt_sema_implicit(sema)								\
+	__asm__ __volatile__ (									\
+	__usdt_asm1(.ifndef sema)								\
+	__usdt_asm3(		.pushsection .probes, "aw", "progbits")				\
+	__usdt_asm1(		.weak sema)							\
+	__usdt_asm1(		.hidden sema)							\
+	__usdt_asm1(		.align 2)							\
+	__usdt_asm1(sema:)									\
+	__usdt_asm1(		.zero 2)							\
+	__usdt_asm2(		.type sema, @object)						\
+	__usdt_asm2(		.size sema, 2)							\
+	__usdt_asm1(		.popsection)							\
+	__usdt_asm1(.endif)									\
+	);
+#endif
+
+/* externally defined semaphore using USDT_DEFINE_SEMA() and passed explicitly by user */
+#ifndef __usdt_sema_explicit
+#define __usdt_sema_explicit(sema)								\
+	__asm__ __volatile__ ("" :: "m" (sema));
+#endif
+
+/* main USDT definition (nop and .note.stapsdt metadata) */
+#define __usdt_probe(group, name, sema_def, sema, ...) do {					\
+	sema_def(sema)										\
+	__asm__ __volatile__ (									\
+	__usdt_asm( 990:	USDT_NOP)							\
+	__usdt_asm3(		.pushsection .note.stapsdt, "", "note")				\
+	__usdt_asm1(		.balign 4)							\
+	__usdt_asm3(		.4byte 992f-991f,994f-993f,3)					\
+	__usdt_asm1(991:	.asciz "stapsdt")						\
+	__usdt_asm1(992:	.balign 4)							\
+	__usdt_asm1(993:	__usdt_asm_addr 990b)						\
+	__usdt_asm1(		__usdt_asm_addr _.stapsdt.base)					\
+	__usdt_asm1(		__usdt_asm_addr sema)						\
+	__usdt_asm_strz(group)									\
+	__usdt_asm_strz(name)									\
+	__usdt_asm_args(__VA_ARGS__)								\
+	__usdt_asm1(		.ascii "\0")							\
+	__usdt_asm1(994:	.balign 4)							\
+	__usdt_asm1(		.popsection)							\
+	__usdt_asm1(.ifndef _.stapsdt.base)							\
+	__usdt_asm5(		.pushsection .stapsdt.base,"aG","progbits",.stapsdt.base,comdat)\
+	__usdt_asm1(		.weak _.stapsdt.base)						\
+	__usdt_asm1(		.hidden _.stapsdt.base)						\
+	__usdt_asm1(_.stapsdt.base:)								\
+	__usdt_asm1(		.space 1)							\
+	__usdt_asm2(		.size _.stapsdt.base, 1)					\
+	__usdt_asm1(		.popsection)							\
+	__usdt_asm1(.endif)									\
+	:: __usdt_asm_ops(__VA_ARGS__)								\
+	);											\
+} while (0)
+
+/*
+ * NB: gdb PR24541 highlighted an unspecified corner of the sdt.h
+ * operand note format.
+ *
+ * The named register may be a longer or shorter (!) alias for the
+ * storage where the value in question is found. For example, on
+ * i386, 64-bit value may be put in register pairs, and a register
+ * name stored would identify just one of them. Previously, gcc was
+ * asked to emit the %w[id] (16-bit alias of some registers holding
+ * operands), even when a wider 32-bit value was used.
+ *
+ * Bottom line: the byte-width given before the @ sign governs. If
+ * there is a mismatch between that width and that of the named
+ * register, then a sys/sdt.h note consumer may need to employ
+ * architecture-specific heuristics to figure out where the compiler
+ * has actually put the complete value.
+ */
+#if defined(__powerpc__) || defined(__powerpc64__)
+#define __usdt_argref(id)	%I[id]%[id]
+#elif defined(__i386__)
+#define __usdt_argref(id)	%k[id]		/* gcc.gnu.org/PR80115 sourceware.org/PR24541 */
+#else
+#define __usdt_argref(id)	%[id]
+#endif
+
+#define __usdt_asm_arg(n)	__usdt_asm_str(%c[__usdt_asz##n])				\
+				__usdt_asm1(.ascii "@")						\
+				__usdt_asm_str(__usdt_argref(__usdt_aval##n))
+
+#define __usdt_asm_args0	/* no arguments */
+#define __usdt_asm_args1	__usdt_asm_arg(1)
+#define __usdt_asm_args2	__usdt_asm_args1 __usdt_asm1(.ascii " ") __usdt_asm_arg(2)
+#define __usdt_asm_args3	__usdt_asm_args2 __usdt_asm1(.ascii " ") __usdt_asm_arg(3)
+#define __usdt_asm_args4	__usdt_asm_args3 __usdt_asm1(.ascii " ") __usdt_asm_arg(4)
+#define __usdt_asm_args5	__usdt_asm_args4 __usdt_asm1(.ascii " ") __usdt_asm_arg(5)
+#define __usdt_asm_args6	__usdt_asm_args5 __usdt_asm1(.ascii " ") __usdt_asm_arg(6)
+#define __usdt_asm_args7	__usdt_asm_args6 __usdt_asm1(.ascii " ") __usdt_asm_arg(7)
+#define __usdt_asm_args8	__usdt_asm_args7 __usdt_asm1(.ascii " ") __usdt_asm_arg(8)
+#define __usdt_asm_args9	__usdt_asm_args8 __usdt_asm1(.ascii " ") __usdt_asm_arg(9)
+#define __usdt_asm_args10	__usdt_asm_args9 __usdt_asm1(.ascii " ") __usdt_asm_arg(10)
+#define __usdt_asm_args11	__usdt_asm_args10 __usdt_asm1(.ascii " ") __usdt_asm_arg(11)
+#define __usdt_asm_args12	__usdt_asm_args11 __usdt_asm1(.ascii " ") __usdt_asm_arg(12)
+#define __usdt_asm_args(...)	__usdt_apply(__usdt_asm_args, __usdt_narg(__VA_ARGS__))
+
+#define __usdt_is_arr(x)	(__builtin_classify_type(x) == 14 || __builtin_classify_type(x) == 5)
+#define __usdt_arg_size(x)	(__usdt_is_arr(x) ? sizeof(void *) : sizeof(x))
+
+/*
+ * We can't use __builtin_choose_expr() in C++, so fall back to table-based
+ * signedness determination for known types, utilizing templates magic.
+ */
+#ifdef __cplusplus
+
+#define __usdt_is_signed(x)	(!__usdt_is_arr(x) && __usdt_t<__typeof(x)>::is_signed)
+
+#include <cstddef>
+
+template<typename T> struct __usdt_t { static const bool is_signed = false; };
+template<typename A> struct __usdt_t<A[]> : public __usdt_t<A *> {};
+template<typename A, size_t N> struct __usdt_t<A[N]> : public __usdt_t<A *> {};
+
+#define __usdt_def_signed(T)									\
+template<> struct __usdt_t<T>		     { static const bool is_signed = true; };		\
+template<> struct __usdt_t<const T>	     { static const bool is_signed = true; };		\
+template<> struct __usdt_t<volatile T>	     { static const bool is_signed = true; };		\
+template<> struct __usdt_t<const volatile T> { static const bool is_signed = true; }
+#define __usdt_maybe_signed(T)									\
+template<> struct __usdt_t<T>		     { static const bool is_signed = (T)-1 < (T)1; };	\
+template<> struct __usdt_t<const T>	     { static const bool is_signed = (T)-1 < (T)1; };	\
+template<> struct __usdt_t<volatile T>	     { static const bool is_signed = (T)-1 < (T)1; };	\
+template<> struct __usdt_t<const volatile T> { static const bool is_signed = (T)-1 < (T)1; }
+
+__usdt_def_signed(signed char);
+__usdt_def_signed(short);
+__usdt_def_signed(int);
+__usdt_def_signed(long);
+__usdt_def_signed(long long);
+__usdt_maybe_signed(char);
+__usdt_maybe_signed(wchar_t);
+
+#else /* !__cplusplus */
+
+#define __usdt_is_inttype(x)	(__builtin_classify_type(x) >= 1 && __builtin_classify_type(x) <= 4)
+#define __usdt_inttype(x)	__typeof(__builtin_choose_expr(__usdt_is_inttype(x), (x), 0U))
+#define __usdt_is_signed(x)	((__usdt_inttype(x))-1 < (__usdt_inttype(x))1)
+
+#endif /* __cplusplus */
+
+#define __usdt_asm_op(n, x)									\
+	[__usdt_asz##n] "n" ((__usdt_is_signed(x) ? (int)-1 : 1) * (int)__usdt_arg_size(x)),	\
+	[__usdt_aval##n] __usdt_str(USDT_ARG_CONSTRAINT)(x)
+
+#define __usdt_asm_ops0()				[__usdt_dummy] "g" (0)
+#define __usdt_asm_ops1(x)				__usdt_asm_op(1, x)
+#define __usdt_asm_ops2(a,x)				__usdt_asm_ops1(a), __usdt_asm_op(2, x)
+#define __usdt_asm_ops3(a,b,x)				__usdt_asm_ops2(a,b), __usdt_asm_op(3, x)
+#define __usdt_asm_ops4(a,b,c,x)			__usdt_asm_ops3(a,b,c), __usdt_asm_op(4, x)
+#define __usdt_asm_ops5(a,b,c,d,x)			__usdt_asm_ops4(a,b,c,d), __usdt_asm_op(5, x)
+#define __usdt_asm_ops6(a,b,c,d,e,x)			__usdt_asm_ops5(a,b,c,d,e), __usdt_asm_op(6, x)
+#define __usdt_asm_ops7(a,b,c,d,e,f,x)			__usdt_asm_ops6(a,b,c,d,e,f), __usdt_asm_op(7, x)
+#define __usdt_asm_ops8(a,b,c,d,e,f,g,x)		__usdt_asm_ops7(a,b,c,d,e,f,g), __usdt_asm_op(8, x)
+#define __usdt_asm_ops9(a,b,c,d,e,f,g,h,x)		__usdt_asm_ops8(a,b,c,d,e,f,g,h), __usdt_asm_op(9, x)
+#define __usdt_asm_ops10(a,b,c,d,e,f,g,h,i,x)		__usdt_asm_ops9(a,b,c,d,e,f,g,h,i), __usdt_asm_op(10, x)
+#define __usdt_asm_ops11(a,b,c,d,e,f,g,h,i,j,x)		__usdt_asm_ops10(a,b,c,d,e,f,g,h,i,j), __usdt_asm_op(11, x)
+#define __usdt_asm_ops12(a,b,c,d,e,f,g,h,i,j,k,x)	__usdt_asm_ops11(a,b,c,d,e,f,g,h,i,j,k), __usdt_asm_op(12, x)
+#define __usdt_asm_ops(...)				__usdt_apply(__usdt_asm_ops, __usdt_narg(__VA_ARGS__))(__VA_ARGS__)
+
+#endif /* __USDT_H */

tools/testing/selftests/seccomp/seccomp_bpf.c

···
 #define noinline __attribute__((noinline))
 #endif
 
+#ifndef __nocf_check
+#define __nocf_check __attribute__((nocf_check))
+#endif
+
+#ifndef __naked
+#define __naked __attribute__((__naked__))
+#endif
+
 #ifndef PR_SET_NO_NEW_PRIVS
 #define PR_SET_NO_NEW_PRIVS 38
 #define PR_GET_NO_NEW_PRIVS 39
···
 	EXPECT_EQ(0, status);
 }
 
-noinline int probed(void)
+#ifdef __x86_64__
+
+/*
+ * We need naked probed_uprobe function. Using __nocf_check
+ * check to skip possible endbr64 instruction and ignoring
+ * -Wattributes, otherwise the compilation might fail.
+ */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wattributes"
+
+__naked __nocf_check noinline int probed_uprobe(void)
+{
+	/*
+	 * Optimized uprobe is possible only on top of nop5 instruction.
+	 */
+	asm volatile ("                                 \n"
+		".byte 0x0f, 0x1f, 0x44, 0x00, 0x00     \n"
+		"ret                                    \n"
+	);
+}
+#pragma GCC diagnostic pop
+
+#else
+noinline int probed_uprobe(void)
+{
+	return 1;
+}
+#endif
+
+noinline int probed_uretprobe(void)
 {
 	return 1;
 }
···
 	return found ? (uintptr_t)addr - start + base : -1;
 }
 
-FIXTURE(URETPROBE) {
+FIXTURE(UPROBE) {
 	int fd;
 };
 
-FIXTURE_VARIANT(URETPROBE) {
+FIXTURE_VARIANT(UPROBE) {
 	/*
-	 * All of the URETPROBE behaviors can be tested with either
-	 * uretprobe attached or not
+	 * All of the U(RET)PROBE behaviors can be tested with either
+	 * u(ret)probe attached or not
 	 */
 	bool attach;
+	/*
+	 * Test both uprobe and uretprobe.
+	 */
+	bool uretprobe;
 };
 
-FIXTURE_VARIANT_ADD(URETPROBE, attached) {
-	.attach = true,
-};
-
-FIXTURE_VARIANT_ADD(URETPROBE, not_attached) {
+FIXTURE_VARIANT_ADD(UPROBE, not_attached) {
 	.attach = false,
+	.uretprobe = false,
 };
 
-FIXTURE_SETUP(URETPROBE)
+FIXTURE_VARIANT_ADD(UPROBE, uprobe_attached) {
+	.attach = true,
+	.uretprobe = false,
+};
+
+FIXTURE_VARIANT_ADD(UPROBE, uretprobe_attached) {
+	.attach = true,
+	.uretprobe = true,
+};
+
+FIXTURE_SETUP(UPROBE)
 {
 	const size_t attr_sz = sizeof(struct perf_event_attr);
 	struct perf_event_attr attr;
 	ssize_t offset;
 	int type, bit;
 
-#ifndef __NR_uretprobe
-	SKIP(return, "__NR_uretprobe syscall not defined");
+#if !defined(__NR_uprobe) || !defined(__NR_uretprobe)
+	SKIP(return, "__NR_uprobe ot __NR_uretprobe syscalls not defined");
 #endif
 
 	if (!variant->attach)
···
 
 	type = determine_uprobe_perf_type();
 	ASSERT_GE(type, 0);
-	bit = determine_uprobe_retprobe_bit();
-	ASSERT_GE(bit, 0);
-	offset = get_uprobe_offset(probed);
+
+	if (variant->uretprobe) {
+		bit = determine_uprobe_retprobe_bit();
+		ASSERT_GE(bit, 0);
+	}
+
+	offset = get_uprobe_offset(variant->uretprobe ? probed_uretprobe : probed_uprobe);
 	ASSERT_GE(offset, 0);
 
-	attr.config |= 1 << bit;
+	if (variant->uretprobe)
+		attr.config |= 1 << bit;
 	attr.size = attr_sz;
 	attr.type = type;
 	attr.config1 = ptr_to_u64("/proc/self/exe");
···
 			   PERF_FLAG_FD_CLOEXEC);
 }
 
-FIXTURE_TEARDOWN(URETPROBE)
+FIXTURE_TEARDOWN(UPROBE)
 {
 	/* we could call close(self->fd), but we'd need extra filter for
 	 * that and since we are calling _exit right away..
···
 		return -1;
 	}
 
-	probed();
+	/*
+	 * Uprobe is optimized after first hit, so let's hit twice.
+	 */
+	probed_uprobe();
+	probed_uprobe();
+
+	probed_uretprobe();
 	return 0;
 }
 
-TEST_F(URETPROBE, uretprobe_default_allow)
+TEST_F(UPROBE, uprobe_default_allow)
 {
 	struct sock_filter filter[] = {
 		BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
···
 	ASSERT_EQ(0, run_probed_with_filter(&prog));
 }
 
-TEST_F(URETPROBE, uretprobe_default_block)
+TEST_F(UPROBE, uprobe_default_block)
 {
 	struct sock_filter filter[] = {
 		BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
···
 	ASSERT_EQ(0, run_probed_with_filter(&prog));
 }
 
-TEST_F(URETPROBE, uretprobe_block_uretprobe_syscall)
+TEST_F(UPROBE, uprobe_block_syscall)
 {
 	struct sock_filter filter[] = {
 		BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
 			offsetof(struct seccomp_data, nr)),
+#ifdef __NR_uprobe
+		BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_uprobe, 1, 2),
+#endif
 #ifdef __NR_uretprobe
 		BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_uretprobe, 0, 1),
 #endif
···
 	ASSERT_EQ(0, run_probed_with_filter(&prog));
 }
 
-TEST_F(URETPROBE, uretprobe_default_block_with_uretprobe_syscall)
+TEST_F(UPROBE, uprobe_default_block_with_syscall)
 {
 	struct sock_filter filter[] = {
 		BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
 			offsetof(struct seccomp_data, nr)),
+#ifdef __NR_uprobe
+		BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_uprobe, 3, 0),
+#endif
 #ifdef __NR_uretprobe
 		BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_uretprobe, 2, 0),
 #endif