[tip: x86/entry] x86/entry: Convert reschedule interrupt to IDTENTRY_SYSVEC_SIMPLE

From: tip-bot2 for Thomas Gleixner
Date: Wed May 27 2020 - 04:11:55 EST

The following commit has been merged into the x86/entry branch of tip:

Commit-ID: 064dc9d647c819f4c3196cdd10c06c0770cabf5f
Gitweb: https://git.kernel.org/tip/064dc9d647c819f4c3196cdd10c06c0770cabf5f
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Thu, 21 May 2020 22:05:45 +02:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 26 May 2020 19:06:29 +02:00

x86/entry: Convert reschedule interrupt to IDTENTRY_SYSVEC_SIMPLE

The scheduler IPI does not need the full interrupt entry handling logic
when the entry is from kernel mode. Use IDTENTRY_SYSVEC_SIMPLE and spare
all the overhead.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Acked-by: Andy Lutomirski <luto@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200521202119.835425642@xxxxxxxxxxxxx
---
arch/x86/entry/entry_64.S | 4 ----
arch/x86/include/asm/entry_arch.h | 3 ---
arch/x86/include/asm/hw_irq.h | 3 ---
arch/x86/include/asm/idtentry.h | 1 +
arch/x86/include/asm/trace/common.h | 4 ----
arch/x86/include/asm/trace/irq_vectors.h | 17 +----------------
arch/x86/kernel/idt.c | 2 +-
arch/x86/kernel/smp.c | 19 ++++---------------
arch/x86/kernel/tracepoint.c | 17 -----------------
9 files changed, 7 insertions(+), 63 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index fd7efb8..9c0722e 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -956,10 +956,6 @@ apicinterrupt3 \num \sym \do_sym
POP_SECTION_IRQENTRY
.endm

-#ifdef CONFIG_SMP
-apicinterrupt RESCHEDULE_VECTOR reschedule_interrupt smp_reschedule_interrupt
-#endif
-
/*
* Reload gs selector with exception handling
* edi: new selector
diff --git a/arch/x86/include/asm/entry_arch.h b/arch/x86/include/asm/entry_arch.h
index a01bb74..3e841ed 100644
--- a/arch/x86/include/asm/entry_arch.h
+++ b/arch/x86/include/asm/entry_arch.h
@@ -10,6 +10,3 @@
* is no hardware IRQ pin equivalent for them, they are triggered
* through the ICC by us (IPIs)
*/
-#ifdef CONFIG_SMP
-BUILD_INTERRUPT(reschedule_interrupt,RESCHEDULE_VECTOR)
-#endif
diff --git a/arch/x86/include/asm/hw_irq.h b/arch/x86/include/asm/hw_irq.h
index fd5e7c8..74c1243 100644
--- a/arch/x86/include/asm/hw_irq.h
+++ b/arch/x86/include/asm/hw_irq.h
@@ -28,9 +28,6 @@
#include <asm/irq.h>
#include <asm/sections.h>

-/* Interrupt handlers registered during init_IRQ */
-extern asmlinkage void reschedule_interrupt(void);
-
#ifdef CONFIG_X86_LOCAL_APIC
struct irq_data;
struct pci_dev;
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index f24701f..d214a30 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -578,6 +578,7 @@ DECLARE_IDTENTRY_SYSVEC(X86_PLATFORM_IPI_VECTOR, sysvec_x86_platform_ipi);
#endif

#ifdef CONFIG_SMP
+DECLARE_IDTENTRY(RESCHEDULE_VECTOR, sysvec_reschedule_ipi);
DECLARE_IDTENTRY_SYSVEC(IRQ_MOVE_CLEANUP_VECTOR, sysvec_irq_move_cleanup);
DECLARE_IDTENTRY_SYSVEC(REBOOT_VECTOR, sysvec_reboot);
DECLARE_IDTENTRY_SYSVEC(CALL_FUNCTION_SINGLE_VECTOR, sysvec_call_function_single);
diff --git a/arch/x86/include/asm/trace/common.h b/arch/x86/include/asm/trace/common.h
index 57c8da0..f0f9bcd 100644
--- a/arch/x86/include/asm/trace/common.h
+++ b/arch/x86/include/asm/trace/common.h
@@ -5,12 +5,8 @@
DECLARE_STATIC_KEY_FALSE(trace_pagefault_key);
#define trace_pagefault_enabled() \
static_branch_unlikely(&trace_pagefault_key)
-DECLARE_STATIC_KEY_FALSE(trace_resched_ipi_key);
-#define trace_resched_ipi_enabled() \
- static_branch_unlikely(&trace_resched_ipi_key)
#else
static inline bool trace_pagefault_enabled(void) { return false; }
-static inline bool trace_resched_ipi_enabled(void) { return false; }
#endif

#endif
diff --git a/arch/x86/include/asm/trace/irq_vectors.h b/arch/x86/include/asm/trace/irq_vectors.h
index 33b9d0f..88e7f0f 100644
--- a/arch/x86/include/asm/trace/irq_vectors.h
+++ b/arch/x86/include/asm/trace/irq_vectors.h
@@ -10,9 +10,6 @@

#ifdef CONFIG_X86_LOCAL_APIC

-extern int trace_resched_ipi_reg(void);
-extern void trace_resched_ipi_unreg(void);
-
DECLARE_EVENT_CLASS(x86_irq_vector,

TP_PROTO(int vector),
@@ -37,18 +34,6 @@ DEFINE_EVENT_FN(x86_irq_vector, name##_exit, \
TP_PROTO(int vector), \
TP_ARGS(vector), NULL, NULL);

-#define DEFINE_RESCHED_IPI_EVENT(name) \
-DEFINE_EVENT_FN(x86_irq_vector, name##_entry, \
- TP_PROTO(int vector), \
- TP_ARGS(vector), \
- trace_resched_ipi_reg, \
- trace_resched_ipi_unreg); \
-DEFINE_EVENT_FN(x86_irq_vector, name##_exit, \
- TP_PROTO(int vector), \
- TP_ARGS(vector), \
- trace_resched_ipi_reg, \
- trace_resched_ipi_unreg);
-
/*
* local_timer - called when entering/exiting a local timer interrupt
* vector handler
@@ -99,7 +84,7 @@ TRACE_EVENT_PERF_PERM(irq_work_exit, is_sampling_event(p_event) ? -EPERM : 0);
/*
* reschedule - called when entering/exiting a reschedule vector handler
*/
-DEFINE_RESCHED_IPI_EVENT(reschedule);
+DEFINE_IRQ_VECTOR_EVENT(reschedule);

/*
* call_function - called when entering/exiting a call function interrupt
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index faaadd4..bc9b0d1 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -112,7 +112,7 @@ static const __initconst struct idt_data def_idts[] = {
*/
static const __initconst struct idt_data apic_idts[] = {
#ifdef CONFIG_SMP
- INTG(RESCHEDULE_VECTOR, reschedule_interrupt),
+ INTG(RESCHEDULE_VECTOR, asm_sysvec_reschedule_ipi),
INTG(CALL_FUNCTION_VECTOR, asm_sysvec_call_function),
INTG(CALL_FUNCTION_SINGLE_VECTOR, asm_sysvec_call_function_single),
INTG(IRQ_MOVE_CLEANUP_VECTOR, asm_sysvec_irq_move_cleanup),
diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index e5647da..eff4ce3 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -220,26 +220,15 @@ static void native_stop_other_cpus(int wait)

/*
* Reschedule call back. KVM uses this interrupt to force a cpu out of
- * guest mode
+ * guest mode.
*/
-__visible void __irq_entry smp_reschedule_interrupt(struct pt_regs *regs)
+DEFINE_IDTENTRY_SYSVEC_SIMPLE(sysvec_reschedule_ipi)
{
ack_APIC_irq();
+ trace_reschedule_entry(RESCHEDULE_VECTOR);
inc_irq_stat(irq_resched_count);
-
- if (trace_resched_ipi_enabled()) {
- /*
- * scheduler_ipi() might call irq_enter() as well, but
- * nested calls are fine.
- */
- irq_enter();
- trace_reschedule_entry(RESCHEDULE_VECTOR);
- scheduler_ipi();
- trace_reschedule_exit(RESCHEDULE_VECTOR);
- irq_exit();
- return;
- }
scheduler_ipi();
+ trace_reschedule_exit(RESCHEDULE_VECTOR);
}

DEFINE_IDTENTRY_SYSVEC(sysvec_call_function)
diff --git a/arch/x86/kernel/tracepoint.c b/arch/x86/kernel/tracepoint.c
index 496748e..fcfc077 100644
--- a/arch/x86/kernel/tracepoint.c
+++ b/arch/x86/kernel/tracepoint.c
@@ -25,20 +25,3 @@ void trace_pagefault_unreg(void)
{
static_branch_dec(&trace_pagefault_key);
}
-
-#ifdef CONFIG_SMP
-
-DEFINE_STATIC_KEY_FALSE(trace_resched_ipi_key);
-
-int trace_resched_ipi_reg(void)
-{
- static_branch_inc(&trace_resched_ipi_key);
- return 0;
-}
-
-void trace_resched_ipi_unreg(void)
-{
- static_branch_dec(&trace_resched_ipi_key);
-}
-
-#endif