perf/x86: Disable extended registers for non-supported PMUs

The perf fuzzer caused Skylake machine to crash:

[ 9680.085831] Call Trace:
[ 9680.088301] <IRQ>
[ 9680.090363] perf_output_sample_regs+0x43/0xa0
[ 9680.094928] perf_output_sample+0x3aa/0x7a0
[ 9680.099181] perf_event_output_forward+0x53/0x80
[ 9680.103917] __perf_event_overflow+0x52/0xf0
[ 9680.108266] ? perf_trace_run_bpf_submit+0xc0/0xc0
[ 9680.113108] perf_swevent_hrtimer+0xe2/0x150
[ 9680.117475] ? check_preempt_wakeup+0x181/0x230
[ 9680.122091] ? check_preempt_curr+0x62/0x90
[ 9680.126361] ? ttwu_do_wakeup+0x19/0x140
[ 9680.130355] ? try_to_wake_up+0x54/0x460
[ 9680.134366] ? reweight_entity+0x15b/0x1a0
[ 9680.138559] ? __queue_work+0x103/0x3f0
[ 9680.142472] ? update_dl_rq_load_avg+0x1cd/0x270
[ 9680.147194] ? timerqueue_del+0x1e/0x40
[ 9680.151092] ? __remove_hrtimer+0x35/0x70
[ 9680.155191] __hrtimer_run_queues+0x100/0x280
[ 9680.159658] hrtimer_interrupt+0x100/0x220
[ 9680.163835] smp_apic_timer_interrupt+0x6a/0x140
[ 9680.168555] apic_timer_interrupt+0xf/0x20
[ 9680.172756] </IRQ>

The XMM registers can only be collected by PEBS hardware events on the
platforms with PEBS baseline support, e.g. Icelake, not software/probe
events.

Add capabilities flag PERF_PMU_CAP_EXTENDED_REGS to indicate the PMU
which support extended registers. For X86, the extended registers are
XMM registers.

Add has_extended_regs() to check if extended registers are applied.

The generic code define the mask of extended registers as 0 if arch
headers haven't overridden it.

Originally-by: Peter Zijlstra (Intel) <[e-mail]>
Reported-by: Vince Weaver <[e-mail]>
Signed-off-by: Kan Liang <[e-mail]>
Signed-off-by: Peter Zijlstra (Intel) <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Arnaldo Carvalho de Melo <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Stephane Eranian <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Fixes: 878068ea270e ("perf/x86: Support outputting XMM registers")
Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

arch/x86/events/intel/ds.c

···
 					PERF_SAMPLE_TIME;
 				x86_pmu.flags |= PMU_FL_PEBS_ALL;
 				pebs_qual = "-baseline";
+				x86_get_pmu()->capabilities |= PERF_PMU_CAP_EXTENDED_REGS;
 			} else {
 				/* Only basic record supported */
 				x86_pmu.pebs_no_xmm_regs = 1;

arch/x86/include/uapi/asm/perf_regs.h

···
 	/* These include both GPRs and XMMX registers */
 	PERF_REG_X86_XMM_MAX = PERF_REG_X86_XMM15 + 2,
 };
+
+#define PERF_REG_EXTENDED_MASK	(~((1ULL << PERF_REG_X86_XMM0) - 1))
+
 #endif /* _ASM_X86_PERF_REGS_H */

include/linux/perf_event.h

···
 #define PERF_PMU_CAP_NO_INTERRUPT		0x01
 #define PERF_PMU_CAP_NO_NMI			0x02
 #define PERF_PMU_CAP_AUX_NO_SG			0x04
+#define PERF_PMU_CAP_EXTENDED_REGS		0x08
 #define PERF_PMU_CAP_EXCLUSIVE			0x10
 #define PERF_PMU_CAP_ITRACE			0x20
 #define PERF_PMU_CAP_HETEROGENEOUS_CPUS		0x40

include/linux/perf_regs.h

···
 
 #ifdef CONFIG_HAVE_PERF_REGS
 #include <asm/perf_regs.h>
+
+#ifndef PERF_REG_EXTENDED_MASK
+#define PERF_REG_EXTENDED_MASK	0
+#endif
+
 u64 perf_reg_value(struct pt_regs *regs, int idx);
 int perf_reg_validate(u64 mask);
 u64 perf_reg_abi(struct task_struct *task);
···
 			struct pt_regs *regs,
 			struct pt_regs *regs_user_copy);
 #else
+
+#define PERF_REG_EXTENDED_MASK	0
+
 static inline u64 perf_reg_value(struct pt_regs *regs, int idx)
 {
 	return 0;

kernel/events/core.c

···
 }
 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
 
+static inline bool has_extended_regs(struct perf_event *event)
+{
+	return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
+	       (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
+}
+
 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
 {
 	struct perf_event_context *ctx = NULL;
···
 		perf_event_ctx_unlock(event->group_leader, ctx);
 
 	if (!ret) {
+		if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
+		    has_extended_regs(event))
+			ret = -EOPNOTSUPP;
+
 		if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
-				event_has_any_exclude_flag(event)) {
-			if (event->destroy)
-				event->destroy(event);
+		    event_has_any_exclude_flag(event))
 			ret = -EINVAL;
-		}
+
+		if (ret && event->destroy)
+			event->destroy(event);
 	}
 
 	if (ret)