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

Pull x86 apic updates from Thomas Gleixner:

- Cleanup the apic IPI implementation by removing duplicated code and
consolidating the functions into the APIC core.

- Implement a safe variant of the IPI broadcast mode. Contrary to
earlier attempts this uses the core tracking of which CPUs have been
brought online at least once so that a broadcast does not end up in
some dead end in BIOS/SMM code when the CPU is still waiting for
init. Once all CPUs have been brought up once, IPI broadcasting is
enabled. Before that regular one by one IPIs are issued.

- Drop the paravirt CR8 related functions as they have no user anymore

- Initialize the APIC TPR to block interrupt 16-31 as they are reserved
for CPU exceptions and should never be raised by any well behaving
device.

- Emit a warning when vector space exhaustion breaks the admin set
affinity of an interrupt.

- Make sure to use the NMI fallback when shutdown via reboot vector IPI
fails. The original code had conditions which prevent the code path
to be reached.

- Annotate various APIC config variables as RO after init.

[ The ipi broadcase change came in earlier through the cpu hotplug
branch, but I left the explanation in the commit message since it was
shared between the two different branches - Linus ]

* 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (28 commits)
x86/apic/vector: Warn when vector space exhaustion breaks affinity
x86/apic: Annotate global config variables as "read-only after init"
x86/apic/x2apic: Implement IPI shorthands support
x86/apic/flat64: Remove the IPI shorthand decision logic
x86/apic: Share common IPI helpers
x86/apic: Remove the shorthand decision logic
x86/smp: Enhance native_send_call_func_ipi()
x86/smp: Move smp_function_call implementations into IPI code
x86/apic: Provide and use helper for send_IPI_allbutself()
x86/apic: Add static key to Control IPI shorthands
x86/apic: Move no_ipi_broadcast() out of 32bit
x86/apic: Add NMI_VECTOR wait to IPI shorthand
x86/apic: Remove dest argument from __default_send_IPI_shortcut()
x86/hotplug: Silence APIC and NMI when CPU is dead
x86/cpu: Move arch_smt_update() to a neutral place
x86/apic/uv: Make x2apic_extra_bits static
x86/apic: Consolidate the apic local headers
x86/apic: Move apic_flat_64 header into apic directory
x86/apic: Move ipi header into apic directory
x86/apic: Cleanup the include maze
...

arch/x86/include/asm/apic.h

···
 extern void clear_local_APIC(void);
 extern void disconnect_bsp_APIC(int virt_wire_setup);
 extern void disable_local_APIC(void);
+extern void apic_soft_disable(void);
 extern void lapic_shutdown(void);
 extern void sync_Arb_IDs(void);
 extern void init_bsp_APIC(void);
···
 extern void lapic_online(void);
 extern void lapic_offline(void);
 extern bool apic_needs_pit(void);
+
+extern void apic_send_IPI_allbutself(unsigned int vector);
 
 #else /* !CONFIG_X86_LOCAL_APIC */
 static inline void lapic_shutdown(void) { }
···
 #define TRAMPOLINE_PHYS_LOW		0x467
 #define TRAMPOLINE_PHYS_HIGH		0x469
 
-#ifdef CONFIG_X86_64
-extern void apic_send_IPI_self(int vector);
-
-DECLARE_PER_CPU(int, x2apic_extra_bits);
-#endif
-
 extern void generic_bigsmp_probe(void);
 
 #ifdef CONFIG_X86_LOCAL_APIC
···
 
 #ifdef CONFIG_SMP
 bool apic_id_is_primary_thread(unsigned int id);
+void apic_smt_update(void);
 #else
 static inline bool apic_id_is_primary_thread(unsigned int id) { return false; }
+static inline void apic_smt_update(void) { }
 #endif
 
 extern void irq_enter(void);

arch/x86/include/asm/apic_flat_64.h

···
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_X86_APIC_FLAT_64_H
-#define _ASM_X86_APIC_FLAT_64_H
-
-extern void flat_init_apic_ldr(void);
-
-#endif
-

arch/x86/include/asm/bugs.h

···
 static inline int ppro_with_ram_bug(void) { return 0; }
 #endif
 
+extern void cpu_bugs_smt_update(void);
+
 #endif /* _ASM_X86_BUGS_H */

arch/x86/include/asm/ipi.h

···
-/* SPDX-License-Identifier: GPL-2.0-only */
-#ifndef _ASM_X86_IPI_H
-#define _ASM_X86_IPI_H
-
-#ifdef CONFIG_X86_LOCAL_APIC
-
-/*
- * Copyright 2004 James Cleverdon, IBM.
- *
- * Generic APIC InterProcessor Interrupt code.
- *
- * Moved to include file by James Cleverdon from
- * arch/x86-64/kernel/smp.c
- *
- * Copyrights from kernel/smp.c:
- *
- * (c) 1995 Alan Cox, Building #3 <[e-mail]>
- * (c) 1998-99, 2000 Ingo Molnar <[e-mail]>
- * (c) 2002,2003 Andi Kleen, SuSE Labs.
- */
-
-#include <asm/hw_irq.h>
-#include <asm/apic.h>
-#include <asm/smp.h>
-
-/*
- * the following functions deal with sending IPIs between CPUs.
- *
- * We use 'broadcast', CPU->CPU IPIs and self-IPIs too.
- */
-
-static inline unsigned int __prepare_ICR(unsigned int shortcut, int vector,
-					 unsigned int dest)
-{
-	unsigned int icr = shortcut | dest;
-
-	switch (vector) {
-	default:
-		icr |= APIC_DM_FIXED | vector;
-		break;
-	case NMI_VECTOR:
-		icr |= APIC_DM_NMI;
-		break;
-	}
-	return icr;
-}
-
-static inline int __prepare_ICR2(unsigned int mask)
-{
-	return SET_APIC_DEST_FIELD(mask);
-}
-
-static inline void __xapic_wait_icr_idle(void)
-{
-	while (native_apic_mem_read(APIC_ICR) & APIC_ICR_BUSY)
-		cpu_relax();
-}
-
-void __default_send_IPI_shortcut(unsigned int shortcut, int vector, unsigned int dest);
-
-/*
- * This is used to send an IPI with no shorthand notation (the destination is
- * specified in bits 56 to 63 of the ICR).
- */
-void __default_send_IPI_dest_field(unsigned int mask, int vector, unsigned int dest);
-
-extern void default_send_IPI_single(int cpu, int vector);
-extern void default_send_IPI_single_phys(int cpu, int vector);
-extern void default_send_IPI_mask_sequence_phys(const struct cpumask *mask,
-						 int vector);
-extern void default_send_IPI_mask_allbutself_phys(const struct cpumask *mask,
-							 int vector);
-
-/* Avoid include hell */
-#define NMI_VECTOR 0x02
-
-extern int no_broadcast;
-
-static inline void __default_local_send_IPI_allbutself(int vector)
-{
-	if (no_broadcast || vector == NMI_VECTOR)
-		apic->send_IPI_mask_allbutself(cpu_online_mask, vector);
-	else
-		__default_send_IPI_shortcut(APIC_DEST_ALLBUT, vector, apic->dest_logical);
-}
-
-static inline void __default_local_send_IPI_all(int vector)
-{
-	if (no_broadcast || vector == NMI_VECTOR)
-		apic->send_IPI_mask(cpu_online_mask, vector);
-	else
-		__default_send_IPI_shortcut(APIC_DEST_ALLINC, vector, apic->dest_logical);
-}
-
-#ifdef CONFIG_X86_32
-extern void default_send_IPI_mask_sequence_logical(const struct cpumask *mask,
-							 int vector);
-extern void default_send_IPI_mask_allbutself_logical(const struct cpumask *mask,
-							 int vector);
-extern void default_send_IPI_mask_logical(const struct cpumask *mask,
-						 int vector);
-extern void default_send_IPI_allbutself(int vector);
-extern void default_send_IPI_all(int vector);
-extern void default_send_IPI_self(int vector);
-#endif
-
-#endif
-
-#endif /* _ASM_X86_IPI_H */

arch/x86/include/asm/paravirt.h

···
 	PVOP_VCALL1(cpu.write_cr4, x);
 }
 
-#ifdef CONFIG_X86_64
-static inline unsigned long read_cr8(void)
-{
-	return PVOP_CALL0(unsigned long, cpu.read_cr8);
-}
-
-static inline void write_cr8(unsigned long x)
-{
-	PVOP_VCALL1(cpu.write_cr8, x);
-}
-#endif
-
 static inline void arch_safe_halt(void)
 {
 	PVOP_VCALL0(irq.safe_halt);

arch/x86/include/asm/paravirt_types.h

···
 
 	void (*write_cr4)(unsigned long);
 
-#ifdef CONFIG_X86_64
-	unsigned long (*read_cr8)(void);
-	void (*write_cr8)(unsigned long);
-#endif
-
 	/* Segment descriptor handling */
 	void (*load_tr_desc)(void);
 	void (*load_gdt)(const struct desc_ptr *);

arch/x86/include/asm/smp.h

···
 void wbinvd_on_cpu(int cpu);
 int wbinvd_on_all_cpus(void);
 
+void native_smp_send_reschedule(int cpu);
 void native_send_call_func_ipi(const struct cpumask *mask);
 void native_send_call_func_single_ipi(int cpu);
 void x86_idle_thread_init(unsigned int cpu, struct task_struct *idle);

arch/x86/include/asm/special_insns.h

···
 
 void native_write_cr4(unsigned long val);
 
-#ifdef CONFIG_X86_64
-static inline unsigned long native_read_cr8(void)
-{
-	unsigned long cr8;
-	asm volatile("movq %%cr8,%0" : "=r" (cr8));
-	return cr8;
-}
-
-static inline void native_write_cr8(unsigned long val)
-{
-	asm volatile("movq %0,%%cr8" :: "r" (val) : "memory");
-}
-#endif
-
 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
 static inline u32 rdpkru(void)
 {
···
 }
 
 #ifdef CONFIG_X86_64
-
-static inline unsigned long read_cr8(void)
-{
-	return native_read_cr8();
-}
-
-static inline void write_cr8(unsigned long x)
-{
-	native_write_cr8(x);
-}
 
 static inline void load_gs_index(unsigned selector)
 {

arch/x86/include/asm/suspend_64.h

···
 	 */
 	unsigned long kernelmode_gs_base, usermode_gs_base, fs_base;
 
-	unsigned long cr0, cr2, cr3, cr4, cr8;
+	unsigned long cr0, cr2, cr3, cr4;
 	u64 misc_enable;
 	bool misc_enable_saved;
 	struct saved_msrs saved_msrs;

arch/x86/kernel/apic/apic.c

···
 unsigned disabled_cpus;
 
 /* Processor that is doing the boot up */
-unsigned int boot_cpu_physical_apicid = -1U;
+unsigned int boot_cpu_physical_apicid __ro_after_init = -1U;
 EXPORT_SYMBOL_GPL(boot_cpu_physical_apicid);
 
-u8 boot_cpu_apic_version;
+u8 boot_cpu_apic_version __ro_after_init;
 
 /*
  * The highest APIC ID seen during enumeration.
···
  * disable_cpu_apicid=<int>, mostly used for the kdump 2nd kernel to
  * avoid undefined behaviour caused by sending INIT from AP to BSP.
  */
-static unsigned int disabled_cpu_apicid __read_mostly = BAD_APICID;
+static unsigned int disabled_cpu_apicid __ro_after_init = BAD_APICID;
 
 /*
  * This variable controls which CPUs receive external NMIs.  By default,
  * external NMIs are delivered only to the BSP.
  */
-static int apic_extnmi = APIC_EXTNMI_BSP;
+static int apic_extnmi __ro_after_init = APIC_EXTNMI_BSP;
 
 /*
  * Map cpu index to physical APIC ID
···
 DEFINE_EARLY_PER_CPU_READ_MOSTLY(int, x86_cpu_to_logical_apicid, BAD_APICID);
 
 /* Local APIC was disabled by the BIOS and enabled by the kernel */
-static int enabled_via_apicbase;
+static int enabled_via_apicbase __ro_after_init;
 
 /*
  * Handle interrupt mode configuration register (IMCR).
···
 __setup("apicpmtimer", setup_apicpmtimer);
 #endif
 
-unsigned long mp_lapic_addr;
-int disable_apic;
+unsigned long mp_lapic_addr __ro_after_init;
+int disable_apic __ro_after_init;
 /* Disable local APIC timer from the kernel commandline or via dmi quirk */
 static int disable_apic_timer __initdata;
 /* Local APIC timer works in C2 */
-int local_apic_timer_c2_ok;
+int local_apic_timer_c2_ok __ro_after_init;
 EXPORT_SYMBOL_GPL(local_apic_timer_c2_ok);
 
 /*
  * Debug level, exported for io_apic.c
  */
-int apic_verbosity;
+int apic_verbosity __ro_after_init;
 
-int pic_mode;
+int pic_mode __ro_after_init;
 
 /* Have we found an MP table */
-int smp_found_config;
+int smp_found_config __ro_after_init;
 
 static struct resource lapic_resource = {
 	.name = "Local APIC",
···
 
 static void apic_pm_activate(void);
 
-static unsigned long apic_phys;
+static unsigned long apic_phys __ro_after_init;
 
 /*
  * Get the LAPIC version
···
 }
 
 /**
+ * apic_soft_disable - Clears and software disables the local APIC on hotplug
+ *
+ * Contrary to disable_local_APIC() this does not touch the enable bit in
+ * MSR_IA32_APICBASE. Clearing that bit on systems based on the 3 wire APIC
+ * bus would require a hardware reset as the APIC would lose track of bus
+ * arbitration. On systems with FSB delivery APICBASE could be disabled,
+ * but it has to be guaranteed that no interrupt is sent to the APIC while
+ * in that state and it's not clear from the SDM whether it still responds
+ * to INIT/SIPI messages. Stay on the safe side and use software disable.
+ */
+void apic_soft_disable(void)
+{
+	u32 value;
+
+	clear_local_APIC();
+
+	/* Soft disable APIC (implies clearing of registers for 82489DX!). */
+	value = apic_read(APIC_SPIV);
+	value &= ~APIC_SPIV_APIC_ENABLED;
+	apic_write(APIC_SPIV, value);
+}
+
+/**
  * disable_local_APIC - clear and disable the local APIC
  */
 void disable_local_APIC(void)
 {
-	unsigned int value;
-
 	/* APIC hasn't been mapped yet */
 	if (!x2apic_mode && !apic_phys)
 		return;
 
-	clear_local_APIC();
-
-	/*
-	 * Disable APIC (implies clearing of registers
-	 * for 82489DX!).
-	 */
-	value = apic_read(APIC_SPIV);
-	value &= ~APIC_SPIV_APIC_ENABLED;
-	apic_write(APIC_SPIV, value);
+	apic_soft_disable();
 
 #ifdef CONFIG_X86_32
 	/*
···
 			APIC_INT_LEVELTRIG | APIC_DM_INIT);
 }
 
-enum apic_intr_mode_id apic_intr_mode;
+enum apic_intr_mode_id apic_intr_mode __ro_after_init;
 
 static int __init apic_intr_mode_select(void)
 {
···
 			oldvalue, value);
 }
 
+#define APIC_IR_REGS		APIC_ISR_NR
+#define APIC_IR_BITS		(APIC_IR_REGS * 32)
+#define APIC_IR_MAPSIZE		(APIC_IR_BITS / BITS_PER_LONG)
+
+union apic_ir {
+	unsigned long	map[APIC_IR_MAPSIZE];
+	u32		regs[APIC_IR_REGS];
+};
+
+static bool apic_check_and_ack(union apic_ir *irr, union apic_ir *isr)
+{
+	int i, bit;
+
+	/* Read the IRRs */
+	for (i = 0; i < APIC_IR_REGS; i++)
+		irr->regs[i] = apic_read(APIC_IRR + i * 0x10);
+
+	/* Read the ISRs */
+	for (i = 0; i < APIC_IR_REGS; i++)
+		isr->regs[i] = apic_read(APIC_ISR + i * 0x10);
+
+	/*
+	 * If the ISR map is not empty. ACK the APIC and run another round
+	 * to verify whether a pending IRR has been unblocked and turned
+	 * into a ISR.
+	 */
+	if (!bitmap_empty(isr->map, APIC_IR_BITS)) {
+		/*
+		 * There can be multiple ISR bits set when a high priority
+		 * interrupt preempted a lower priority one. Issue an ACK
+		 * per set bit.
+		 */
+		for_each_set_bit(bit, isr->map, APIC_IR_BITS)
+			ack_APIC_irq();
+		return true;
+	}
+
+	return !bitmap_empty(irr->map, APIC_IR_BITS);
+}
+
+/*
+ * After a crash, we no longer service the interrupts and a pending
+ * interrupt from previous kernel might still have ISR bit set.
+ *
+ * Most probably by now the CPU has serviced that pending interrupt and it
+ * might not have done the ack_APIC_irq() because it thought, interrupt
+ * came from i8259 as ExtInt. LAPIC did not get EOI so it does not clear
+ * the ISR bit and cpu thinks it has already serivced the interrupt. Hence
+ * a vector might get locked. It was noticed for timer irq (vector
+ * 0x31). Issue an extra EOI to clear ISR.
+ *
+ * If there are pending IRR bits they turn into ISR bits after a higher
+ * priority ISR bit has been acked.
+ */
 static void apic_pending_intr_clear(void)
 {
-	long long max_loops = cpu_khz ? cpu_khz : 1000000;
-	unsigned long long tsc = 0, ntsc;
-	unsigned int queued;
-	unsigned long value;
-	int i, j, acked = 0;
+	union apic_ir irr, isr;
+	unsigned int i;
 
-	if (boot_cpu_has(X86_FEATURE_TSC))
-		tsc = rdtsc();
-	/*
-	 * After a crash, we no longer service the interrupts and a pending
-	 * interrupt from previous kernel might still have ISR bit set.
-	 *
-	 * Most probably by now CPU has serviced that pending interrupt and
-	 * it might not have done the ack_APIC_irq() because it thought,
-	 * interrupt came from i8259 as ExtInt. LAPIC did not get EOI so it
-	 * does not clear the ISR bit and cpu thinks it has already serivced
-	 * the interrupt. Hence a vector might get locked. It was noticed
-	 * for timer irq (vector 0x31). Issue an extra EOI to clear ISR.
-	 */
-	do {
-		queued = 0;
-		for (i = APIC_ISR_NR - 1; i >= 0; i--)
-			queued |= apic_read(APIC_IRR + i*0x10);
-
-		for (i = APIC_ISR_NR - 1; i >= 0; i--) {
-			value = apic_read(APIC_ISR + i*0x10);
-			for_each_set_bit(j, &value, 32) {
-				ack_APIC_irq();
-				acked++;
-			}
-		}
-		if (acked > 256) {
-			pr_err("LAPIC pending interrupts after %d EOI\n", acked);
-			break;
-		}
-		if (queued) {
-			if (boot_cpu_has(X86_FEATURE_TSC) && cpu_khz) {
-				ntsc = rdtsc();
-				max_loops = (long long)cpu_khz << 10;
-				max_loops -= ntsc - tsc;
-			} else {
-				max_loops--;
-			}
-		}
-	} while (queued && max_loops > 0);
-	WARN_ON(max_loops <= 0);
+	/* 512 loops are way oversized and give the APIC a chance to obey. */
+	for (i = 0; i < 512; i++) {
+		if (!apic_check_and_ack(&irr, &isr))
+			return;
+	}
+	/* Dump the IRR/ISR content if that failed */
+	pr_warn("APIC: Stale IRR: %256pb ISR: %256pb\n", irr.map, isr.map);
 }
 
 /**
···
 	int logical_apicid, ldr_apicid;
 #endif
 
-
 	if (disable_apic) {
 		disable_ioapic_support();
 		return;
 	}
+
+	/*
+	 * If this comes from kexec/kcrash the APIC might be enabled in
+	 * SPIV. Soft disable it before doing further initialization.
+	 */
+	value = apic_read(APIC_SPIV);
+	value &= ~APIC_SPIV_APIC_ENABLED;
+	apic_write(APIC_SPIV, value);
 
 #ifdef CONFIG_X86_32
 	/* Pound the ESR really hard over the head with a big hammer - mbligh */
···
 		apic_write(APIC_ESR, 0);
 	}
 #endif
-	perf_events_lapic_init();
-
 	/*
 	 * Double-check whether this APIC is really registered.
 	 * This is meaningless in clustered apic mode, so we skip it.
···
 #endif
 
 	/*
-	 * Set Task Priority to 'accept all'. We never change this
-	 * later on.
+	 * Set Task Priority to 'accept all except vectors 0-31'.  An APIC
+	 * vector in the 16-31 range could be delivered if TPR == 0, but we
+	 * would think it's an exception and terrible things will happen.  We
+	 * never change this later on.
 	 */
 	value = apic_read(APIC_TASKPRI);
 	value &= ~APIC_TPRI_MASK;
+	value |= 0x10;
 	apic_write(APIC_TASKPRI, value);
 
+	/* Clear eventually stale ISR/IRR bits */
 	apic_pending_intr_clear();
 
 	/*
···
 	 */
 	value |= SPURIOUS_APIC_VECTOR;
 	apic_write(APIC_SPIV, value);
+
+	perf_events_lapic_init();
 
 	/*
 	 * Set up LVT0, LVT1:

arch/x86/kernel/apic/apic_flat_64.c

···
  * Martin Bligh, Andi Kleen, James Bottomley, John Stultz, and
  * James Cleverdon.
  */
-#include <linux/acpi.h>
-#include <linux/errno.h>
-#include <linux/threads.h>
 #include <linux/cpumask.h>
-#include <linux/string.h>
-#include <linux/kernel.h>
-#include <linux/ctype.h>
-#include <linux/hardirq.h>
 #include <linux/export.h>
+#include <linux/acpi.h>
 
-#include <asm/smp.h>
-#include <asm/ipi.h>
-#include <asm/apic.h>
-#include <asm/apic_flat_64.h>
 #include <asm/jailhouse_para.h>
+#include <asm/apic.h>
+
+#include "local.h"
 
 static struct apic apic_physflat;
 static struct apic apic_flat;
···
 		__clear_bit(cpu, &mask);
 
 	_flat_send_IPI_mask(mask, vector);
-}
-
-static void flat_send_IPI_allbutself(int vector)
-{
-	int cpu = smp_processor_id();
-
-	if (IS_ENABLED(CONFIG_HOTPLUG_CPU) || vector == NMI_VECTOR) {
-		if (!cpumask_equal(cpu_online_mask, cpumask_of(cpu))) {
-			unsigned long mask = cpumask_bits(cpu_online_mask)[0];
-
-			if (cpu < BITS_PER_LONG)
-				__clear_bit(cpu, &mask);
-
-			_flat_send_IPI_mask(mask, vector);
-		}
-	} else if (num_online_cpus() > 1) {
-		__default_send_IPI_shortcut(APIC_DEST_ALLBUT,
-					    vector, apic->dest_logical);
-	}
-}
-
-static void flat_send_IPI_all(int vector)
-{
-	if (vector == NMI_VECTOR) {
-		flat_send_IPI_mask(cpu_online_mask, vector);
-	} else {
-		__default_send_IPI_shortcut(APIC_DEST_ALLINC,
-					    vector, apic->dest_logical);
-	}
 }
 
 static unsigned int flat_get_apic_id(unsigned long x)
···
 	.send_IPI			= default_send_IPI_single,
 	.send_IPI_mask			= flat_send_IPI_mask,
 	.send_IPI_mask_allbutself	= flat_send_IPI_mask_allbutself,
-	.send_IPI_allbutself		= flat_send_IPI_allbutself,
-	.send_IPI_all			= flat_send_IPI_all,
-	.send_IPI_self			= apic_send_IPI_self,
+	.send_IPI_allbutself		= default_send_IPI_allbutself,
+	.send_IPI_all			= default_send_IPI_all,
+	.send_IPI_self			= default_send_IPI_self,
 
 	.inquire_remote_apic		= default_inquire_remote_apic,
 
···
 	 */
 }
 
-static void physflat_send_IPI_allbutself(int vector)
-{
-	default_send_IPI_mask_allbutself_phys(cpu_online_mask, vector);
-}
-
-static void physflat_send_IPI_all(int vector)
-{
-	default_send_IPI_mask_sequence_phys(cpu_online_mask, vector);
-}
-
 static int physflat_probe(void)
 {
 	if (apic == &apic_physflat || num_possible_cpus() > 8 ||
···
 	.send_IPI			= default_send_IPI_single_phys,
 	.send_IPI_mask			= default_send_IPI_mask_sequence_phys,
 	.send_IPI_mask_allbutself	= default_send_IPI_mask_allbutself_phys,
-	.send_IPI_allbutself		= physflat_send_IPI_allbutself,
-	.send_IPI_all			= physflat_send_IPI_all,
-	.send_IPI_self			= apic_send_IPI_self,
+	.send_IPI_allbutself		= default_send_IPI_allbutself,
+	.send_IPI_all			= default_send_IPI_all,
+	.send_IPI_self			= default_send_IPI_self,
 
 	.inquire_remote_apic		= default_inquire_remote_apic,
 

arch/x86/kernel/apic/apic_noop.c

···
  * to not uglify the caller's code and allow to call (some) apic routines
  * like self-ipi, etc...
  */
-
-#include <linux/threads.h>
 #include <linux/cpumask.h>
-#include <linux/string.h>
-#include <linux/kernel.h>
-#include <linux/ctype.h>
-#include <linux/errno.h>
-#include <asm/fixmap.h>
-#include <asm/mpspec.h>
-#include <asm/apicdef.h>
+
 #include <asm/apic.h>
-#include <asm/setup.h>
-
-#include <linux/smp.h>
-#include <asm/ipi.h>
-
-#include <linux/interrupt.h>
-#include <asm/acpi.h>
-#include <asm/e820/api.h>
 
 static void noop_init_apic_ldr(void) { }
 static void noop_send_IPI(int cpu, int vector) { }

arch/x86/kernel/apic/apic_numachip.c

···
  * Send feedback to <[e-mail]>
  *
  */
-
+#include <linux/types.h>
 #include <linux/init.h>
 
 #include <asm/numachip/numachip.h>
 #include <asm/numachip/numachip_csr.h>
-#include <asm/ipi.h>
-#include <asm/apic_flat_64.h>
+
 #include <asm/pgtable.h>
-#include <asm/pci_x86.h>
+
+#include "local.h"
 
 u8 numachip_system __read_mostly;
 static const struct apic apic_numachip1;

arch/x86/kernel/apic/bigsmp_32.c

···
  *
  * Drives the local APIC in "clustered mode".
  */
-#include <linux/threads.h>
 #include <linux/cpumask.h>
-#include <linux/kernel.h>
-#include <linux/init.h>
 #include <linux/dmi.h>
 #include <linux/smp.h>
 
-#include <asm/apicdef.h>
-#include <asm/fixmap.h>
-#include <asm/mpspec.h>
 #include <asm/apic.h>
-#include <asm/ipi.h>
+
+#include "local.h"
 
 static unsigned bigsmp_get_apic_id(unsigned long x)
 {

arch/x86/kernel/apic/ipi.c

···
 // SPDX-License-Identifier: GPL-2.0
+
 #include <linux/cpumask.h>
-#include <linux/interrupt.h>
+#include <linux/smp.h>
 
-#include <linux/mm.h>
-#include <linux/delay.h>
-#include <linux/spinlock.h>
-#include <linux/kernel_stat.h>
-#include <linux/mc146818rtc.h>
-#include <linux/cache.h>
-#include <linux/cpu.h>
+#include "local.h"
 
-#include <asm/smp.h>
-#include <asm/mtrr.h>
-#include <asm/tlbflush.h>
-#include <asm/mmu_context.h>
-#include <asm/apic.h>
-#include <asm/proto.h>
-#include <asm/ipi.h>
+DEFINE_STATIC_KEY_FALSE(apic_use_ipi_shorthand);
 
-void __default_send_IPI_shortcut(unsigned int shortcut, int vector, unsigned int dest)
+#ifdef CONFIG_SMP
+static int apic_ipi_shorthand_off __ro_after_init;
+
+static __init int apic_ipi_shorthand(char *str)
+{
+	get_option(&str, &apic_ipi_shorthand_off);
+	return 1;
+}
+__setup("no_ipi_broadcast=", apic_ipi_shorthand);
+
+static int __init print_ipi_mode(void)
+{
+	pr_info("IPI shorthand broadcast: %s\n",
+		apic_ipi_shorthand_off ? "disabled" : "enabled");
+	return 0;
+}
+late_initcall(print_ipi_mode);
+
+void apic_smt_update(void)
+{
+	/*
+	 * Do not switch to broadcast mode if:
+	 * - Disabled on the command line
+	 * - Only a single CPU is online
+	 * - Not all present CPUs have been at least booted once
+	 *
+	 * The latter is important as the local APIC might be in some
+	 * random state and a broadcast might cause havoc. That's
+	 * especially true for NMI broadcasting.
+	 */
+	if (apic_ipi_shorthand_off || num_online_cpus() == 1 ||
+	    !cpumask_equal(cpu_present_mask, &cpus_booted_once_mask)) {
+		static_branch_disable(&apic_use_ipi_shorthand);
+	} else {
+		static_branch_enable(&apic_use_ipi_shorthand);
+	}
+}
+
+void apic_send_IPI_allbutself(unsigned int vector)
+{
+	if (num_online_cpus() < 2)
+		return;
+
+	if (static_branch_likely(&apic_use_ipi_shorthand))
+		apic->send_IPI_allbutself(vector);
+	else
+		apic->send_IPI_mask_allbutself(cpu_online_mask, vector);
+}
+
+/*
+ * Send a 'reschedule' IPI to another CPU. It goes straight through and
+ * wastes no time serializing anything. Worst case is that we lose a
+ * reschedule ...
+ */
+void native_smp_send_reschedule(int cpu)
+{
+	if (unlikely(cpu_is_offline(cpu))) {
+		WARN(1, "sched: Unexpected reschedule of offline CPU#%d!\n", cpu);
+		return;
+	}
+	apic->send_IPI(cpu, RESCHEDULE_VECTOR);
+}
+
+void native_send_call_func_single_ipi(int cpu)
+{
+	apic->send_IPI(cpu, CALL_FUNCTION_SINGLE_VECTOR);
+}
+
+void native_send_call_func_ipi(const struct cpumask *mask)
+{
+	if (static_branch_likely(&apic_use_ipi_shorthand)) {
+		unsigned int cpu = smp_processor_id();
+
+		if (!cpumask_or_equal(mask, cpumask_of(cpu), cpu_online_mask))
+			goto sendmask;
+
+		if (cpumask_test_cpu(cpu, mask))
+			apic->send_IPI_all(CALL_FUNCTION_VECTOR);
+		else if (num_online_cpus() > 1)
+			apic->send_IPI_allbutself(CALL_FUNCTION_VECTOR);
+		return;
+	}
+
+sendmask:
+	apic->send_IPI_mask(mask, CALL_FUNCTION_VECTOR);
+}
+
+#endif /* CONFIG_SMP */
+
+static inline int __prepare_ICR2(unsigned int mask)
+{
+	return SET_APIC_DEST_FIELD(mask);
+}
+
+static inline void __xapic_wait_icr_idle(void)
+{
+	while (native_apic_mem_read(APIC_ICR) & APIC_ICR_BUSY)
+		cpu_relax();
+}
+
+void __default_send_IPI_shortcut(unsigned int shortcut, int vector)
 {
 	/*
 	 * Subtle. In the case of the 'never do double writes' workaround
···
 	/*
 	 * Wait for idle.
 	 */
-	__xapic_wait_icr_idle();
+	if (unlikely(vector == NMI_VECTOR))
+		safe_apic_wait_icr_idle();
+	else
+		__xapic_wait_icr_idle();
 
 	/*
-	 * No need to touch the target chip field
+	 * No need to touch the target chip field. Also the destination
+	 * mode is ignored when a shorthand is used.
 	 */
-	cfg = __prepare_ICR(shortcut, vector, dest);
+	cfg = __prepare_ICR(shortcut, vector, 0);
 
 	/*
 	 * Send the IPI. The write to APIC_ICR fires this off.
···
 	apic->send_IPI_mask(cpumask_of(cpu), vector);
 }
 
+void default_send_IPI_allbutself(int vector)
+{
+	__default_send_IPI_shortcut(APIC_DEST_ALLBUT, vector);
+}
+
+void default_send_IPI_all(int vector)
+{
+	__default_send_IPI_shortcut(APIC_DEST_ALLINC, vector);
+}
+
+void default_send_IPI_self(int vector)
+{
+	__default_send_IPI_shortcut(APIC_DEST_SELF, vector);
+}
+
 #ifdef CONFIG_X86_32
 
 void default_send_IPI_mask_sequence_logical(const struct cpumask *mask,
···
 	WARN_ON(mask & ~cpumask_bits(cpu_online_mask)[0]);
 	__default_send_IPI_dest_field(mask, vector, apic->dest_logical);
 	local_irq_restore(flags);
-}
-
-void default_send_IPI_allbutself(int vector)
-{
-	/*
-	 * if there are no other CPUs in the system then we get an APIC send
-	 * error if we try to broadcast, thus avoid sending IPIs in this case.
-	 */
-	if (!(num_online_cpus() > 1))
-		return;
-
-	__default_local_send_IPI_allbutself(vector);
-}
-
-void default_send_IPI_all(int vector)
-{
-	__default_local_send_IPI_all(vector);
-}
-
-void default_send_IPI_self(int vector)
-{
-	__default_send_IPI_shortcut(APIC_DEST_SELF, vector, apic->dest_logical);
 }
 
 /* must come after the send_IPI functions above for inlining */

arch/x86/kernel/apic/local.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Historical copyright notices:
+ *
+ * Copyright 2004 James Cleverdon, IBM.
+ * (c) 1995 Alan Cox, Building #3 <[e-mail]>
+ * (c) 1998-99, 2000 Ingo Molnar <[e-mail]>
+ * (c) 2002,2003 Andi Kleen, SuSE Labs.
+ */
+
+#include <linux/jump_label.h>
+
+#include <asm/apic.h>
+
+/* APIC flat 64 */
+void flat_init_apic_ldr(void);
+
+/* X2APIC */
+int x2apic_apic_id_valid(u32 apicid);
+int x2apic_apic_id_registered(void);
+void __x2apic_send_IPI_dest(unsigned int apicid, int vector, unsigned int dest);
+unsigned int x2apic_get_apic_id(unsigned long id);
+u32 x2apic_set_apic_id(unsigned int id);
+int x2apic_phys_pkg_id(int initial_apicid, int index_msb);
+void x2apic_send_IPI_self(int vector);
+void __x2apic_send_IPI_shorthand(int vector, u32 which);
+
+/* IPI */
+
+DECLARE_STATIC_KEY_FALSE(apic_use_ipi_shorthand);
+
+static inline unsigned int __prepare_ICR(unsigned int shortcut, int vector,
+					 unsigned int dest)
+{
+	unsigned int icr = shortcut | dest;
+
+	switch (vector) {
+	default:
+		icr |= APIC_DM_FIXED | vector;
+		break;
+	case NMI_VECTOR:
+		icr |= APIC_DM_NMI;
+		break;
+	}
+	return icr;
+}
+
+void __default_send_IPI_shortcut(unsigned int shortcut, int vector);
+
+/*
+ * This is used to send an IPI with no shorthand notation (the destination is
+ * specified in bits 56 to 63 of the ICR).
+ */
+void __default_send_IPI_dest_field(unsigned int mask, int vector, unsigned int dest);
+
+void default_send_IPI_single(int cpu, int vector);
+void default_send_IPI_single_phys(int cpu, int vector);
+void default_send_IPI_mask_sequence_phys(const struct cpumask *mask, int vector);
+void default_send_IPI_mask_allbutself_phys(const struct cpumask *mask, int vector);
+void default_send_IPI_allbutself(int vector);
+void default_send_IPI_all(int vector);
+void default_send_IPI_self(int vector);
+
+#ifdef CONFIG_X86_32
+void default_send_IPI_mask_sequence_logical(const struct cpumask *mask, int vector);
+void default_send_IPI_mask_allbutself_logical(const struct cpumask *mask, int vector);
+void default_send_IPI_mask_logical(const struct cpumask *mask, int vector);
+#endif

arch/x86/kernel/apic/probe_32.c

···
  *
  * Generic x86 APIC driver probe layer.
  */
-#include <linux/threads.h>
-#include <linux/cpumask.h>
 #include <linux/export.h>
-#include <linux/string.h>
-#include <linux/kernel.h>
-#include <linux/ctype.h>
-#include <linux/init.h>
 #include <linux/errno.h>
-#include <asm/fixmap.h>
-#include <asm/mpspec.h>
-#include <asm/apicdef.h>
-#include <asm/apic.h>
-#include <asm/setup.h>
-
 #include <linux/smp.h>
-#include <asm/ipi.h>
 
-#include <linux/interrupt.h>
+#include <asm/apic.h>
 #include <asm/acpi.h>
-#include <asm/e820/api.h>
 
-#ifdef CONFIG_HOTPLUG_CPU
-#define DEFAULT_SEND_IPI	(1)
-#else
-#define DEFAULT_SEND_IPI	(0)
-#endif
-
-int no_broadcast = DEFAULT_SEND_IPI;
-
-static __init int no_ipi_broadcast(char *str)
-{
-	get_option(&str, &no_broadcast);
-	pr_info("Using %s mode\n",
-		no_broadcast ? "No IPI Broadcast" : "IPI Broadcast");
-	return 1;
-}
-__setup("no_ipi_broadcast=", no_ipi_broadcast);
-
-static int __init print_ipi_mode(void)
-{
-	pr_info("Using IPI %s mode\n",
-		no_broadcast ? "No-Shortcut" : "Shortcut");
-	return 0;
-}
-late_initcall(print_ipi_mode);
+#include "local.h"
 
 static int default_x86_32_early_logical_apicid(int cpu)
 {

arch/x86/kernel/apic/probe_64.c

···
  * Martin Bligh, Andi Kleen, James Bottomley, John Stultz, and
  * James Cleverdon.
  */
-#include <linux/threads.h>
-#include <linux/cpumask.h>
-#include <linux/string.h>
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/ctype.h>
-#include <linux/hardirq.h>
-#include <linux/dmar.h>
-
-#include <asm/smp.h>
 #include <asm/apic.h>
-#include <asm/ipi.h>
-#include <asm/setup.h>
+
+#include "local.h"
 
 /*
  * Check the APIC IDs in bios_cpu_apicid and choose the APIC mode.
···
 
 	if (x86_platform.apic_post_init)
 		x86_platform.apic_post_init();
-}
-
-/* Same for both flat and physical. */
-
-void apic_send_IPI_self(int vector)
-{
-	__default_send_IPI_shortcut(APIC_DEST_SELF, vector, APIC_DEST_PHYSICAL);
 }
 
 int __init default_acpi_madt_oem_check(char *oem_id, char *oem_table_id)

arch/x86/kernel/apic/vector.c

···
 		if (!irqd_can_reserve(irqd))
 			apicd->can_reserve = false;
 	}
+
+	/*
+	 * Check to ensure that the effective affinity mask is a subset
+	 * the user supplied affinity mask, and warn the user if it is not
+	 */
+	if (!cpumask_subset(irq_data_get_effective_affinity_mask(irqd),
+			    irq_data_get_affinity_mask(irqd))) {
+		pr_warn("irq %u: Affinity broken due to vector space exhaustion.\n",
+			irqd->irq);
+	}
+
 	return ret;
 }
 

arch/x86/kernel/apic/x2apic.h

···
-/* Common bits for X2APIC cluster/physical modes. */
-
-int x2apic_apic_id_valid(u32 apicid);
-int x2apic_apic_id_registered(void);
-void __x2apic_send_IPI_dest(unsigned int apicid, int vector, unsigned int dest);
-unsigned int x2apic_get_apic_id(unsigned long id);
-u32 x2apic_set_apic_id(unsigned int id);
-int x2apic_phys_pkg_id(int initial_apicid, int index_msb);
-void x2apic_send_IPI_self(int vector);

arch/x86/kernel/apic/x2apic_cluster.c

···
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/threads.h>
-#include <linux/cpumask.h>
-#include <linux/string.h>
-#include <linux/kernel.h>
-#include <linux/ctype.h>
-#include <linux/dmar.h>
-#include <linux/irq.h>
-#include <linux/cpu.h>
 
-#include <asm/smp.h>
-#include "x2apic.h"
+#include <linux/cpuhotplug.h>
+#include <linux/cpumask.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+
+#include <asm/apic.h>
+
+#include "local.h"
 
 struct cluster_mask {
 	unsigned int	clusterid;
···
 
 static void x2apic_send_IPI_allbutself(int vector)
 {
-	__x2apic_send_IPI_mask(cpu_online_mask, vector, APIC_DEST_ALLBUT);
+	__x2apic_send_IPI_shorthand(vector, APIC_DEST_ALLBUT);
 }
 
 static void x2apic_send_IPI_all(int vector)
 {
-	__x2apic_send_IPI_mask(cpu_online_mask, vector, APIC_DEST_ALLINC);
+	__x2apic_send_IPI_shorthand(vector, APIC_DEST_ALLINC);
 }
 
 static u32 x2apic_calc_apicid(unsigned int cpu)

arch/x86/kernel/apic/x2apic_phys.c

···
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/threads.h>
-#include <linux/cpumask.h>
-#include <linux/string.h>
-#include <linux/kernel.h>
-#include <linux/ctype.h>
-#include <linux/dmar.h>
 
-#include <asm/smp.h>
-#include <asm/ipi.h>
-#include "x2apic.h"
+#include <linux/cpumask.h>
+#include <linux/acpi.h>
+
+#include "local.h"
 
 int x2apic_phys;
 
···
 
 static void x2apic_send_IPI_allbutself(int vector)
 {
-	__x2apic_send_IPI_mask(cpu_online_mask, vector, APIC_DEST_ALLBUT);
+	__x2apic_send_IPI_shorthand(vector, APIC_DEST_ALLBUT);
 }
 
 static void x2apic_send_IPI_all(int vector)
 {
-	__x2apic_send_IPI_mask(cpu_online_mask, vector, APIC_DEST_ALLINC);
+	__x2apic_send_IPI_shorthand(vector, APIC_DEST_ALLINC);
 }
 
 static void init_x2apic_ldr(void)
···
 {
 	unsigned long cfg = __prepare_ICR(0, vector, dest);
 	native_x2apic_icr_write(cfg, apicid);
+}
+
+void __x2apic_send_IPI_shorthand(int vector, u32 which)
+{
+	unsigned long cfg = __prepare_ICR(which, vector, 0);
+
+	x2apic_wrmsr_fence();
+	native_x2apic_icr_write(cfg, 0);
 }
 
 unsigned int x2apic_get_apic_id(unsigned long id)

arch/x86/kernel/apic/x2apic_uv_x.c

···
  *
  * Copyright (C) 2007-2014 Silicon Graphics, Inc. All rights reserved.
  */
-#include <linux/cpumask.h>
-#include <linux/hardirq.h>
-#include <linux/proc_fs.h>
-#include <linux/threads.h>
-#include <linux/kernel.h>
-#include <linux/export.h>
-#include <linux/string.h>
-#include <linux/ctype.h>
-#include <linux/sched.h>
-#include <linux/timer.h>
-#include <linux/slab.h>
-#include <linux/cpu.h>
-#include <linux/init.h>
-#include <linux/io.h>
-#include <linux/pci.h>
-#include <linux/kdebug.h>
-#include <linux/delay.h>
 #include <linux/crash_dump.h>
-#include <linux/reboot.h>
+#include <linux/cpuhotplug.h>
+#include <linux/cpumask.h>
+#include <linux/proc_fs.h>
 #include <linux/memory.h>
-#include <linux/numa.h>
+#include <linux/export.h>
+#include <linux/pci.h>
 
+#include <asm/e820/api.h>
 #include <asm/uv/uv_mmrs.h>
 #include <asm/uv/uv_hub.h>
-#include <asm/current.h>
-#include <asm/pgtable.h>
 #include <asm/uv/bios.h>
 #include <asm/uv/uv.h>
 #include <asm/apic.h>
-#include <asm/e820/api.h>
-#include <asm/ipi.h>
-#include <asm/smp.h>
-#include <asm/x86_init.h>
-#include <asm/nmi.h>
 
-DEFINE_PER_CPU(int, x2apic_extra_bits);
+static DEFINE_PER_CPU(int, x2apic_extra_bits);
 
 static enum uv_system_type	uv_system_type;
 static bool			uv_hubless_system;

arch/x86/kernel/asm-offsets_64.c

···
 	ENTRY(cr2);
 	ENTRY(cr3);
 	ENTRY(cr4);
-	ENTRY(cr8);
 	ENTRY(gdt_desc);
 	BLANK();
 #undef ENTRY

arch/x86/kernel/cpu/bugs.c

···
 
 #define MDS_MSG_SMT "MDS CPU bug present and SMT on, data leak possible. See https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/mds.html for more details.\n"
 
-void arch_smt_update(void)
+void cpu_bugs_smt_update(void)
 {
 	/* Enhanced IBRS implies STIBP. No update required. */
 	if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED)

arch/x86/kernel/cpu/common.c

···
 	pr_warn("x86/CPU: CPU features have changed after loading microcode, but might not take effect.\n");
 	pr_warn("x86/CPU: Please consider either early loading through initrd/built-in or a potential BIOS update.\n");
 }
+
+/*
+ * Invoked from core CPU hotplug code after hotplug operations
+ */
+void arch_smt_update(void)
+{
+	/* Handle the speculative execution misfeatures */
+	cpu_bugs_smt_update();
+	/* Check whether IPI broadcasting can be enabled */
+	apic_smt_update();
+}

arch/x86/kernel/kgdb.c

···
  */
 void kgdb_roundup_cpus(void)
 {
-	apic->send_IPI_allbutself(APIC_DM_NMI);
+	apic_send_IPI_allbutself(NMI_VECTOR);
 }
 #endif
 

arch/x86/kernel/nmi.c

···
 dotraplinkage notrace void
 do_nmi(struct pt_regs *regs, long error_code)
 {
+	if (IS_ENABLED(CONFIG_SMP) && cpu_is_offline(smp_processor_id()))
+		return;
+
 	if (this_cpu_read(nmi_state) != NMI_NOT_RUNNING) {
 		this_cpu_write(nmi_state, NMI_LATCHED);
 		return;

arch/x86/kernel/paravirt.c

···
 	.cpu.read_cr0		= native_read_cr0,
 	.cpu.write_cr0		= native_write_cr0,
 	.cpu.write_cr4		= native_write_cr4,
-#ifdef CONFIG_X86_64
-	.cpu.read_cr8		= native_read_cr8,
-	.cpu.write_cr8		= native_write_cr8,
-#endif
 	.cpu.wbinvd		= native_wbinvd,
 	.cpu.read_msr		= native_read_msr,
 	.cpu.write_msr		= native_write_msr,

arch/x86/kernel/reboot.c

···
 	return NMI_HANDLED;
 }
 
-static void smp_send_nmi_allbutself(void)
-{
-	apic->send_IPI_allbutself(NMI_VECTOR);
-}
-
 /*
  * Halt all other CPUs, calling the specified function on each of them
  *
···
 	 */
 	wmb();
 
-	smp_send_nmi_allbutself();
+	apic_send_IPI_allbutself(NMI_VECTOR);
 
 	/* Kick CPUs looping in NMI context. */
 	WRITE_ONCE(crash_ipi_issued, 1);

arch/x86/kernel/smp.c

···
 static atomic_t stopping_cpu = ATOMIC_INIT(-1);
 static bool smp_no_nmi_ipi = false;
 
-/*
- * this function sends a 'reschedule' IPI to another CPU.
- * it goes straight through and wastes no time serializing
- * anything. Worst case is that we lose a reschedule ...
- */
-static void native_smp_send_reschedule(int cpu)
-{
-	if (unlikely(cpu_is_offline(cpu))) {
-		WARN(1, "sched: Unexpected reschedule of offline CPU#%d!\n", cpu);
-		return;
-	}
-	apic->send_IPI(cpu, RESCHEDULE_VECTOR);
-}
-
-void native_send_call_func_single_ipi(int cpu)
-{
-	apic->send_IPI(cpu, CALL_FUNCTION_SINGLE_VECTOR);
-}
-
-void native_send_call_func_ipi(const struct cpumask *mask)
-{
-	cpumask_var_t allbutself;
-
-	if (!alloc_cpumask_var(&allbutself, GFP_ATOMIC)) {
-		apic->send_IPI_mask(mask, CALL_FUNCTION_VECTOR);
-		return;
-	}
-
-	cpumask_copy(allbutself, cpu_online_mask);
-	__cpumask_clear_cpu(smp_processor_id(), allbutself);
-
-	if (cpumask_equal(mask, allbutself) &&
-	    cpumask_equal(cpu_online_mask, cpu_callout_mask))
-		apic->send_IPI_allbutself(CALL_FUNCTION_VECTOR);
-	else
-		apic->send_IPI_mask(mask, CALL_FUNCTION_VECTOR);
-
-	free_cpumask_var(allbutself);
-}
-
 static int smp_stop_nmi_callback(unsigned int val, struct pt_regs *regs)
 {
 	/* We are registered on stopping cpu too, avoid spurious NMI */
···
 	cpu_emergency_vmxoff();
 	stop_this_cpu(NULL);
 	irq_exit();
+}
+
+static int register_stop_handler(void)
+{
+	return register_nmi_handler(NMI_LOCAL, smp_stop_nmi_callback,
+				    NMI_FLAG_FIRST, "smp_stop");
 }
 
 static void native_stop_other_cpus(int wait)
···
 		/* sync above data before sending IRQ */
 		wmb();
 
-		apic->send_IPI_allbutself(REBOOT_VECTOR);
+		apic_send_IPI_allbutself(REBOOT_VECTOR);
 
 		/*
-		 * Don't wait longer than a second if the caller
-		 * didn't ask us to wait.
+		 * Don't wait longer than a second for IPI completion. The
+		 * wait request is not checked here because that would
+		 * prevent an NMI shutdown attempt in case that not all
+		 * CPUs reach shutdown state.
 		 */
 		timeout = USEC_PER_SEC;
-		while (num_online_cpus() > 1 && (wait || timeout--))
+		while (num_online_cpus() > 1 && timeout--)
 			udelay(1);
 	}
-	
+
 	/* if the REBOOT_VECTOR didn't work, try with the NMI */
-	if ((num_online_cpus() > 1) && (!smp_no_nmi_ipi))  {
-		if (register_nmi_handler(NMI_LOCAL, smp_stop_nmi_callback,
-					 NMI_FLAG_FIRST, "smp_stop"))
-			/* Note: we ignore failures here */
-			/* Hope the REBOOT_IRQ is good enough */
-			goto finish;
-
-		/* sync above data before sending IRQ */
-		wmb();
-
-		pr_emerg("Shutting down cpus with NMI\n");
-
-		apic->send_IPI_allbutself(NMI_VECTOR);
-
+	if (num_online_cpus() > 1) {
 		/*
-		 * Don't wait longer than a 10 ms if the caller
-		 * didn't ask us to wait.
+		 * If NMI IPI is enabled, try to register the stop handler
+		 * and send the IPI. In any case try to wait for the other
+		 * CPUs to stop.
+		 */
+		if (!smp_no_nmi_ipi && !register_stop_handler()) {
+			/* Sync above data before sending IRQ */
+			wmb();
+
+			pr_emerg("Shutting down cpus with NMI\n");
+
+			apic_send_IPI_allbutself(NMI_VECTOR);
+		}
+		/*
+		 * Don't wait longer than 10 ms if the caller didn't
+		 * reqeust it. If wait is true, the machine hangs here if
+		 * one or more CPUs do not reach shutdown state.
 		 */
 		timeout = USEC_PER_MSEC * 10;
 		while (num_online_cpus() > 1 && (wait || timeout--))
 			udelay(1);
 	}
 
-finish:
 	local_irq_save(flags);
 	disable_local_APIC();
 	mcheck_cpu_clear(this_cpu_ptr(&cpu_info));

arch/x86/kernel/smpboot.c

···
 	if (ret)
 		return ret;
 
-	clear_local_APIC();
+	/*
+	 * Disable the local APIC. Otherwise IPI broadcasts will reach
+	 * it. It still responds normally to INIT, NMI, SMI, and SIPI
+	 * messages.
+	 */
+	apic_soft_disable();
 	cpu_disable_common();
 
 	return 0;

arch/x86/power/cpu.c

···
 	ctxt->cr2 = read_cr2();
 	ctxt->cr3 = __read_cr3();
 	ctxt->cr4 = __read_cr4();
-#ifdef CONFIG_X86_64
-	ctxt->cr8 = read_cr8();
-#endif
 	ctxt->misc_enable_saved = !rdmsrl_safe(MSR_IA32_MISC_ENABLE,
 					       &ctxt->misc_enable);
 	msr_save_context(ctxt);
···
 #else
 /* CONFIG X86_64 */
 	wrmsrl(MSR_EFER, ctxt->efer);
-	write_cr8(ctxt->cr8);
 	__write_cr4(ctxt->cr4);
 #endif
 	write_cr3(ctxt->cr3);

arch/x86/xen/enlighten_pv.c

···
 
 	native_write_cr4(cr4);
 }
-#ifdef CONFIG_X86_64
-static inline unsigned long xen_read_cr8(void)
-{
-	return 0;
-}
-static inline void xen_write_cr8(unsigned long val)
-{
-	BUG_ON(val);
-}
-#endif
 
 static u64 xen_read_msr_safe(unsigned int msr, int *err)
 {
···
 	.write_cr0 = xen_write_cr0,
 
 	.write_cr4 = xen_write_cr4,
-
-#ifdef CONFIG_X86_64
-	.read_cr8 = xen_read_cr8,
-	.write_cr8 = xen_write_cr8,
-#endif
 
 	.wbinvd = native_wbinvd,