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From: tip-bot for Thomas Gleixner <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: peterz@infradead.org, bp@alien8.de, luto@kernel.org,
	torvalds@linux-foundation.org, hpa@zytor.com, mingo@kernel.org,
	tglx@linutronix.de, rostedt@goodmis.org,
	linux-kernel@vger.kernel.org
Subject: [tip:x86/apic] x86/traps: Simplify pagefault tracing logic
Date: Tue, 29 Aug 2017 04:06:39 -0700	[thread overview]
Message-ID: <tip-11a7ffb01703c3bbb1e9b968893f4487a1b0b5a8@git.kernel.org> (raw)
In-Reply-To: <20170828064956.672965407@linutronix.de>

Commit-ID:  11a7ffb01703c3bbb1e9b968893f4487a1b0b5a8
Gitweb:     http://git.kernel.org/tip/11a7ffb01703c3bbb1e9b968893f4487a1b0b5a8
Author:     Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Mon, 28 Aug 2017 08:47:22 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 29 Aug 2017 11:42:23 +0200

x86/traps: Simplify pagefault tracing logic

Make use of the new irqvector tracing static key and remove the duplicated
trace_do_pagefault() implementation.

If irq vector tracing is disabled, then the overhead of this is a single
NOP5, which is a reasonable tradeoff to avoid duplicated code and the
unholy macro mess.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170828064956.672965407@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/entry/entry_32.S    |  8 --------
 arch/x86/entry/entry_64.S    | 13 +-----------
 arch/x86/include/asm/traps.h | 10 +--------
 arch/x86/kernel/kvm.c        |  2 +-
 arch/x86/mm/fault.c          | 49 ++++++++++++--------------------------------
 5 files changed, 16 insertions(+), 66 deletions(-)

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 48ef7bb..0092da1 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -891,14 +891,6 @@ BUILD_INTERRUPT3(hyperv_callback_vector, HYPERVISOR_CALLBACK_VECTOR,
 
 #endif /* CONFIG_HYPERV */
 
-#ifdef CONFIG_TRACING
-ENTRY(trace_page_fault)
-	ASM_CLAC
-	pushl	$trace_do_page_fault
-	jmp	common_exception
-END(trace_page_fault)
-#endif
-
 ENTRY(page_fault)
 	ASM_CLAC
 	pushl	$do_page_fault
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 4dbb336..2731b94 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -918,17 +918,6 @@ ENTRY(\sym)
 END(\sym)
 .endm
 
-#ifdef CONFIG_TRACING
-.macro trace_idtentry sym do_sym has_error_code:req
-idtentry trace(\sym) trace(\do_sym) has_error_code=\has_error_code
-idtentry \sym \do_sym has_error_code=\has_error_code
-.endm
-#else
-.macro trace_idtentry sym do_sym has_error_code:req
-idtentry \sym \do_sym has_error_code=\has_error_code
-.endm
-#endif
-
 idtentry divide_error			do_divide_error			has_error_code=0
 idtentry overflow			do_overflow			has_error_code=0
 idtentry bounds				do_bounds			has_error_code=0
@@ -1096,7 +1085,7 @@ idtentry xen_stack_segment	do_stack_segment	has_error_code=1
 #endif
 
 idtentry general_protection	do_general_protection	has_error_code=1
-trace_idtentry page_fault	do_page_fault		has_error_code=1
+idtentry page_fault		do_page_fault		has_error_code=1
 
 #ifdef CONFIG_KVM_GUEST
 idtentry async_page_fault	do_async_page_fault	has_error_code=1
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index 01fd0a7..b4f322d 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -39,7 +39,6 @@ asmlinkage void machine_check(void);
 asmlinkage void simd_coprocessor_error(void);
 
 #ifdef CONFIG_TRACING
-asmlinkage void trace_page_fault(void);
 #define trace_stack_segment stack_segment
 #define trace_divide_error divide_error
 #define trace_bounds bounds
@@ -54,6 +53,7 @@ asmlinkage void trace_page_fault(void);
 #define trace_alignment_check alignment_check
 #define trace_simd_coprocessor_error simd_coprocessor_error
 #define trace_async_page_fault async_page_fault
+#define trace_page_fault page_fault
 #endif
 
 dotraplinkage void do_divide_error(struct pt_regs *, long);
@@ -74,14 +74,6 @@ asmlinkage struct pt_regs *sync_regs(struct pt_regs *);
 #endif
 dotraplinkage void do_general_protection(struct pt_regs *, long);
 dotraplinkage void do_page_fault(struct pt_regs *, unsigned long);
-#ifdef CONFIG_TRACING
-dotraplinkage void trace_do_page_fault(struct pt_regs *, unsigned long);
-#else
-static inline void trace_do_page_fault(struct pt_regs *regs, unsigned long error)
-{
-	do_page_fault(regs, error);
-}
-#endif
 dotraplinkage void do_spurious_interrupt_bug(struct pt_regs *, long);
 dotraplinkage void do_coprocessor_error(struct pt_regs *, long);
 dotraplinkage void do_alignment_check(struct pt_regs *, long);
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index d04e30e..6ed9242 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -263,7 +263,7 @@ do_async_page_fault(struct pt_regs *regs, unsigned long error_code)
 
 	switch (kvm_read_and_reset_pf_reason()) {
 	default:
-		trace_do_page_fault(regs, error_code);
+		do_page_fault(regs, error_code);
 		break;
 	case KVM_PV_REASON_PAGE_NOT_PRESENT:
 		/* page is swapped out by the host. */
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 2a1fa10c..58d7b3a 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1254,10 +1254,6 @@ static inline bool smap_violation(int error_code, struct pt_regs *regs)
  * This routine handles page faults.  It determines the address,
  * and the problem, and then passes it off to one of the appropriate
  * routines.
- *
- * This function must have noinline because both callers
- * {,trace_}do_page_fault() have notrace on. Having this an actual function
- * guarantees there's a function trace entry.
  */
 static noinline void
 __do_page_fault(struct pt_regs *regs, unsigned long error_code,
@@ -1490,27 +1486,6 @@ good_area:
 }
 NOKPROBE_SYMBOL(__do_page_fault);
 
-dotraplinkage void notrace
-do_page_fault(struct pt_regs *regs, unsigned long error_code)
-{
-	unsigned long address = read_cr2(); /* Get the faulting address */
-	enum ctx_state prev_state;
-
-	/*
-	 * We must have this function tagged with __kprobes, notrace and call
-	 * read_cr2() before calling anything else. To avoid calling any kind
-	 * of tracing machinery before we've observed the CR2 value.
-	 *
-	 * exception_{enter,exit}() contain all sorts of tracepoints.
-	 */
-
-	prev_state = exception_enter();
-	__do_page_fault(regs, error_code, address);
-	exception_exit(prev_state);
-}
-NOKPROBE_SYMBOL(do_page_fault);
-
-#ifdef CONFIG_TRACING
 static nokprobe_inline void
 trace_page_fault_entries(unsigned long address, struct pt_regs *regs,
 			 unsigned long error_code)
@@ -1521,22 +1496,24 @@ trace_page_fault_entries(unsigned long address, struct pt_regs *regs,
 		trace_page_fault_kernel(address, regs, error_code);
 }
 
+/*
+ * We must have this function blacklisted from kprobes, tagged with notrace
+ * and call read_cr2() before calling anything else. To avoid calling any
+ * kind of tracing machinery before we've observed the CR2 value.
+ *
+ * exception_{enter,exit}() contains all sorts of tracepoints.
+ */
 dotraplinkage void notrace
-trace_do_page_fault(struct pt_regs *regs, unsigned long error_code)
+do_page_fault(struct pt_regs *regs, unsigned long error_code)
 {
-	/*
-	 * The exception_enter and tracepoint processing could
-	 * trigger another page faults (user space callchain
-	 * reading) and destroy the original cr2 value, so read
-	 * the faulting address now.
-	 */
-	unsigned long address = read_cr2();
+	unsigned long address = read_cr2(); /* Get the faulting address */
 	enum ctx_state prev_state;
 
 	prev_state = exception_enter();
-	trace_page_fault_entries(address, regs, error_code);
+	if (trace_irqvectors_enabled())
+		trace_page_fault_entries(address, regs, error_code);
+
 	__do_page_fault(regs, error_code, address);
 	exception_exit(prev_state);
 }
-NOKPROBE_SYMBOL(trace_do_page_fault);
-#endif /* CONFIG_TRACING */
+NOKPROBE_SYMBOL(do_page_fault);

  reply	other threads:[~2017-08-29 11:11 UTC|newest]

Thread overview: 95+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-28  6:47 [patch V3 00/44] x86: Cleanup IDT code Thomas Gleixner
2017-08-28  6:47 ` [patch V3 01/44] x86/irq: Remove vector_used_by_percpu_irq() Thomas Gleixner
2017-08-29 11:04   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 02/44] x86/irq: Unexport used_vectors Thomas Gleixner
2017-08-29 11:04   ` [tip:x86/apic] x86/irq: Unexport used_vectors[] tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 03/44] x86/irq: Get rid of the first_system_vector bogisity Thomas Gleixner
2017-08-29 11:04   ` [tip:x86/apic] x86/irq: Get rid of the 'first_system_vector' indirection bogosity tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 04/44] x86/irq: Remove duplicated used_vectors definition Thomas Gleixner
2017-08-29 11:05   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 05/44] x86/boot: Move EISA setup to a proper place Thomas Gleixner
2017-08-29 11:05   ` [tip:x86/apic] x86/boot: Move EISA setup to a separate file tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 06/44] x86/tracing: Introduce a static key for exception tracing Thomas Gleixner
2017-08-29 11:06   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 07/44] x86/traps: Simplify pagefault tracing logic Thomas Gleixner
2017-08-29 11:06   ` tip-bot for Thomas Gleixner [this message]
2017-08-28  6:47 ` [patch V3 08/44] x86/apic: Remove the duplicated tracing version of local_timer_interrupt Thomas Gleixner
2017-08-29 11:07   ` [tip:x86/apic] x86/apic: Remove the duplicated tracing version of local_timer_interrupt() tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 09/44] x86/apic: Use this_cpu_ptr in local_timer_interrupt Thomas Gleixner
2017-08-29 11:07   ` [tip:x86/apic] x86/apic: Use this_cpu_ptr() in local_timer_interrupt() tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 10/44] x86/irq: Get rid of duplicated trace_x86_platform_ipi() code Thomas Gleixner
2017-08-29 11:07   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 11/44] x86/apic: Remove the duplicated tracing versions of interrupts Thomas Gleixner
2017-08-29 11:08   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 12/44] x86/irqwork: Get rid of duplicated tracing interrupt code Thomas Gleixner
2017-08-29 11:08   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 13/44] x86/mce: Remove " Thomas Gleixner
2017-08-29 11:08   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 14/44] x86/smp: Remove pointless duplicated " Thomas Gleixner
2017-08-29 11:09   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 15/44] x86/smp: Use static key for reschedule interrupt tracing Thomas Gleixner
2017-08-29 11:09   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 16/44] x86/idt: Remove tracing idt completely Thomas Gleixner
2017-08-29 11:10   ` [tip:x86/apic] x86/idt: Remove the tracing IDT completely tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 17/44] x86/idt: Cleanup the i386 low level entry macros Thomas Gleixner
2017-08-29 11:10   ` [tip:x86/apic] x86/idt: Clean up " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 18/44] x86/tracing: Disentangle pagefault and resched IPI tracing key Thomas Gleixner
2017-08-29 11:10   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 19/44] x86/ipi: Make platform IPI depend on APIC Thomas Gleixner
2017-08-29 11:11   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 20/44] x86/irq_work: Make it " Thomas Gleixner
2017-08-29 11:11   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 21/44] x86/tracing: Build tracepoints only when they are used Thomas Gleixner
2017-08-29 11:12   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 22/44] x86/idt: Unify gate_struct handling for 32/64bit Thomas Gleixner
2017-08-29 11:12   ` [tip:x86/apic] x86/idt: Unify gate_struct handling for 32/64-bit kernels tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 23/44] x86/percpu: Use static initializer for GDT entry Thomas Gleixner
2017-08-29 11:13   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 24/44] x86/fpu: Use bitfield accessors for desc_struct Thomas Gleixner
2017-08-29 11:13   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 25/44] x86: Replace access to desc_struct:a/b fields Thomas Gleixner
2017-08-29 11:13   ` [tip:x86/apic] x86/asm: " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 26/44] x86/gdt: Use bitfields for initialization Thomas Gleixner
2017-08-29 11:14   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 27/44] x86/ldttss: Cleanup 32bit descriptors Thomas Gleixner
2017-08-29 11:14   ` [tip:x86/apic] x86/ldttss: Clean up 32-bit descriptors tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 28/44] x86/idt: Create file for IDT related code Thomas Gleixner
2017-08-29 11:15   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 29/44] x86/idt: Move 32bit idt_descr to C code Thomas Gleixner
2017-08-29 11:15   ` [tip:x86/apic] x86/idt: Move 32-bit " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 30/44] x86/idt: Remove unused set_trap_gate() Thomas Gleixner
2017-08-29 11:16   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 31/44] x86/idt: Consolidate IDT invalidation Thomas Gleixner
2017-08-29 11:16   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 32/44] x86/idt: Move early IDT handler setup to IDT code Thomas Gleixner
2017-08-29 11:16   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 33/44] x86/idt: Move early IDT setup out of 32bit asm Thomas Gleixner
2017-08-29 11:17   ` [tip:x86/apic] x86/idt: Move early IDT setup out of 32-bit asm tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 34/44] x86/idt: Prepare for table based init Thomas Gleixner
2017-08-29 11:17   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 35/44] x86/idt: Switch early trap init to IDT tables Thomas Gleixner
2017-08-29 11:18   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 36/44] x86/idt: Move debug stack init to table based Thomas Gleixner
2017-08-29 11:18   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 37/44] x86/idt: Move ist stack based traps to table init Thomas Gleixner
2017-08-29 11:18   ` [tip:x86/apic] x86/idt: Move IST " tip-bot for Thomas Gleixner
2017-09-01  6:28     ` Andrei Vagin
2017-09-01  8:26       ` [PATCH] x86/idt: Fix the X86_TRAP_BP gate Ingo Molnar
2017-09-01  8:59         ` Thomas Gleixner
2017-09-01  9:09         ` [tip:x86/apic] " tip-bot for Ingo Molnar
2017-09-01 14:39         ` [PATCH] " Andrei Vagin
2017-08-28  6:47 ` [patch V3 38/44] x86/idt: Move regular trap init to tables Thomas Gleixner
2017-08-29 11:19   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 39/44] x86/idt: Move APIC gate initialization " Thomas Gleixner
2017-08-29 11:19   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 40/44] x86/idt: Move interrupt gate initialization to IDT code Thomas Gleixner
2017-08-29 11:20   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 41/44] x86/idt: Remove unused functions/inlines Thomas Gleixner
2017-08-29 11:20   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 42/44] x86/idt: Deinline setup functions Thomas Gleixner
2017-08-29 11:20   ` [tip:x86/apic] " tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 43/44] x86/idt: Simplify alloc_intr_gate Thomas Gleixner
2017-08-28 14:35   ` KY Srinivasan
2017-08-29 11:21   ` [tip:x86/apic] x86/idt: Simplify alloc_intr_gate() tip-bot for Thomas Gleixner
2017-08-28  6:47 ` [patch V3 44/44] x86/idt: Hide set_intr_gate() Thomas Gleixner
2017-08-29 11:21   ` [tip:x86/apic] " tip-bot for Thomas Gleixner

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