Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Thomas Gleixner:
"A set of fixes for x86:

- Fix the bogus detection of 32bit user mode for uretprobes which
caused corruption of the user return address resulting in
application crashes. In the uprobes handler in_ia32_syscall() is
obviously always returning false on a 64bit kernel. Use
user_64bit_mode() instead which works correctly.

- Prevent large page splitting when ftrace flips RW/RO on the kernel
text which caused iTLB performance issues. Ftrace wants to be
converted to text_poke() which avoids the problem, but for now
allow large page preservation in the static protections check when
the change request spawns a full large page.

- Prevent arch_dynirq_lower_bound() from returning 0 when the IOAPIC
is configured via device tree. In the device tree case the GSI 1:1
mapping is meaningless therefore the lower bound which protects the
GSI range on ACPI machines is irrelevant. Return the lower bound
which the core hands to the function instead of blindly returning 0
which causes the core to allocate the invalid virtual interupt
number 0 which in turn prevents all drivers from allocating and
requesting an interrupt.

- Remove the bogus initialization of LDR and DFR in the 32bit bigsmp
APIC driver. That uses physical destination mode where LDR/DFR are
ignored, but the initialization and the missing clear of LDR caused
the APIC to be left in a inconsistent state on kexec/reboot.

- Clear LDR when clearing the APIC registers so the APIC is in a well
defined state.

- Initialize variables proper in the find_trampoline_placement()
code.

- Silence GCC( build warning for the real mode part of the build"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm/cpa: Prevent large page split when ftrace flips RW on kernel text
x86/build: Add -Wnoaddress-of-packed-member to REALMODE_CFLAGS, to silence GCC9 build warning
x86/boot/compressed/64: Fix missing initialization in find_trampoline_placement()
x86/apic: Include the LDR when clearing out APIC registers
x86/apic: Do not initialize LDR and DFR for bigsmp
uprobes/x86: Fix detection of 32-bit user mode
x86/apic: Fix arch_dynirq_lower_bound() bug for DT enabled machines

arch/x86/Makefile

···
 
 REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -ffreestanding)
 REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -fno-stack-protector)
+REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -Wno-address-of-packed-member)
 REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4))
 export REALMODE_CFLAGS
 

arch/x86/boot/compressed/pgtable_64.c

···
 
 	/* Find the first usable memory region under bios_start. */
 	for (i = boot_params->e820_entries - 1; i >= 0; i--) {
-		unsigned long new;
+		unsigned long new = bios_start;
 
 		entry = &boot_params->e820_table[i];
 

arch/x86/kernel/apic/apic.c

···
 	apic_write(APIC_LVT0, v | APIC_LVT_MASKED);
 	v = apic_read(APIC_LVT1);
 	apic_write(APIC_LVT1, v | APIC_LVT_MASKED);
+	if (!x2apic_enabled()) {
+		v = apic_read(APIC_LDR) & ~APIC_LDR_MASK;
+		apic_write(APIC_LDR, v);
+	}
 	if (maxlvt >= 4) {
 		v = apic_read(APIC_LVTPC);
 		apic_write(APIC_LVTPC, v | APIC_LVT_MASKED);

arch/x86/kernel/apic/bigsmp_32.c

···
 	return early_per_cpu(x86_cpu_to_apicid, cpu);
 }
 
-static inline unsigned long calculate_ldr(int cpu)
-{
-	unsigned long val, id;
-
-	val = apic_read(APIC_LDR) & ~APIC_LDR_MASK;
-	id = per_cpu(x86_bios_cpu_apicid, cpu);
-	val |= SET_APIC_LOGICAL_ID(id);
-
-	return val;
-}
-
 /*
- * Set up the logical destination ID.
- *
- * Intel recommends to set DFR, LDR and TPR before enabling
- * an APIC.  See e.g. "AP-388 82489DX User's Manual" (Intel
- * document number 292116).  So here it goes...
+ * bigsmp enables physical destination mode
+ * and doesn't use LDR and DFR
  */
 static void bigsmp_init_apic_ldr(void)
 {
-	unsigned long val;
-	int cpu = smp_processor_id();
-
-	apic_write(APIC_DFR, APIC_DFR_FLAT);
-	val = calculate_ldr(cpu);
-	apic_write(APIC_LDR, val);
 }
 
 static void bigsmp_setup_apic_routing(void)

arch/x86/kernel/apic/io_apic.c

···
 	 * dmar_alloc_hwirq() may be called before setup_IO_APIC(), so use
 	 * gsi_top if ioapic_dynirq_base hasn't been initialized yet.
 	 */
-	return ioapic_initialized ? ioapic_dynirq_base : gsi_top;
+	if (!ioapic_initialized)
+		return gsi_top;
+	/*
+	 * For DT enabled machines ioapic_dynirq_base is irrelevant and not
+	 * updated. So simply return @from if ioapic_dynirq_base == 0.
+	 */
+	return ioapic_dynirq_base ? : from;
 }
 
 #ifdef CONFIG_X86_32

arch/x86/kernel/uprobes.c

···
 	void	(*abort)(struct arch_uprobe *, struct pt_regs *);
 };
 
-static inline int sizeof_long(void)
+static inline int sizeof_long(struct pt_regs *regs)
 {
-	return in_ia32_syscall() ? 4 : 8;
+	/*
+	 * Check registers for mode as in_xxx_syscall() does not apply here.
+	 */
+	return user_64bit_mode(regs) ? 8 : 4;
 }
 
 static int default_pre_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs)
···
 
 static int emulate_push_stack(struct pt_regs *regs, unsigned long val)
 {
-	unsigned long new_sp = regs->sp - sizeof_long();
+	unsigned long new_sp = regs->sp - sizeof_long(regs);
 
-	if (copy_to_user((void __user *)new_sp, &val, sizeof_long()))
+	if (copy_to_user((void __user *)new_sp, &val, sizeof_long(regs)))
 		return -EFAULT;
 
 	regs->sp = new_sp;
···
 		long correction = utask->vaddr - utask->xol_vaddr;
 		regs->ip += correction;
 	} else if (auprobe->defparam.fixups & UPROBE_FIX_CALL) {
-		regs->sp += sizeof_long(); /* Pop incorrect return address */
+		regs->sp += sizeof_long(regs); /* Pop incorrect return address */
 		if (emulate_push_stack(regs, utask->vaddr + auprobe->defparam.ilen))
 			return -ERESTART;
 	}
···
 	 * "call" insn was executed out-of-line. Just restore ->sp and restart.
 	 * We could also restore ->ip and try to call branch_emulate_op() again.
 	 */
-	regs->sp += sizeof_long();
+	regs->sp += sizeof_long(regs);
 	return -ERESTART;
 }
 
···
 unsigned long
 arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs *regs)
 {
-	int rasize = sizeof_long(), nleft;
+	int rasize = sizeof_long(regs), nleft;
 	unsigned long orig_ret_vaddr = 0; /* clear high bits for 32-bit apps */
 
 	if (copy_from_user(&orig_ret_vaddr, (void __user *)regs->sp, rasize))

arch/x86/mm/pageattr.c

···
  */
 static inline pgprot_t static_protections(pgprot_t prot, unsigned long start,
 					  unsigned long pfn, unsigned long npg,
-					  int warnlvl)
+					  unsigned long lpsize, int warnlvl)
 {
 	pgprotval_t forbidden, res;
 	unsigned long end;
···
 	check_conflict(warnlvl, prot, res, start, end, pfn, "Text NX");
 	forbidden = res;
 
-	res = protect_kernel_text_ro(start, end);
-	check_conflict(warnlvl, prot, res, start, end, pfn, "Text RO");
-	forbidden |= res;
+	/*
+	 * Special case to preserve a large page. If the change spawns the
+	 * full large page mapping then there is no point to split it
+	 * up. Happens with ftrace and is going to be removed once ftrace
+	 * switched to text_poke().
+	 */
+	if (lpsize != (npg * PAGE_SIZE) || (start & (lpsize - 1))) {
+		res = protect_kernel_text_ro(start, end);
+		check_conflict(warnlvl, prot, res, start, end, pfn, "Text RO");
+		forbidden |= res;
+	}
 
 	/* Check the PFN directly */
 	res = protect_pci_bios(pfn, pfn + npg - 1);
···
 	 * extra conditional required here.
 	 */
 	chk_prot = static_protections(old_prot, lpaddr, old_pfn, numpages,
-				      CPA_CONFLICT);
+				      psize, CPA_CONFLICT);
 
 	if (WARN_ON_ONCE(pgprot_val(chk_prot) != pgprot_val(old_prot))) {
 		/*
···
 	 * protection requirement in the large page.
 	 */
 	new_prot = static_protections(req_prot, lpaddr, old_pfn, numpages,
-				      CPA_DETECT);
+				      psize, CPA_DETECT);
 
 	/*
 	 * If there is a conflict, split the large page.
···
 	if (!cpa->force_static_prot)
 		goto set;
 
-	prot = static_protections(ref_prot, address, pfn, npg, CPA_PROTECT);
+	/* Hand in lpsize = 0 to enforce the protection mechanism */
+	prot = static_protections(ref_prot, address, pfn, npg, 0, CPA_PROTECT);
 
 	if (pgprot_val(prot) == pgprot_val(ref_prot))
 		goto set;
···
 		pgprot_val(new_prot) |= pgprot_val(cpa->mask_set);
 
 		cpa_inc_4k_install();
-		new_prot = static_protections(new_prot, address, pfn, 1,
+		/* Hand in lpsize = 0 to enforce the protection mechanism */
+		new_prot = static_protections(new_prot, address, pfn, 1, 0,
 					      CPA_PROTECT);
 
 		new_prot = pgprot_clear_protnone_bits(new_prot);