[PATCH v4 0/4] Introduce page fault tracepoints

[PATCH v4 0/4] Introduce page fault tracepoints

[Seiji Aguchi]

Change from v3:
 - Separate modifications to make review easy.
 - Refactor implementations registering exception/irq_vector
   handers. (Patch 1, 2, 3)

This series introduce page fault tracepoints.

Detailed descriptions are explained in each patch.
Any comments are welcome.

Seiji Aguchi (4):
  Move set_intr_gate() into macro
  Register exception handler to trace IDT
  Delete __trace_alloc_intr_gate()
  Add page fault tracepoints

 arch/x86/include/asm/desc.h             | 57 ++++++++++++++-------------------
 arch/x86/include/asm/hw_irq.h           |  3 ++
 arch/x86/include/asm/segment.h          |  3 ++
 arch/x86/include/asm/trace/exceptions.h | 52 ++++++++++++++++++++++++++++++
 arch/x86/include/asm/traps.h            | 20 ++++++++++++
 arch/x86/kernel/entry_32.S              | 10 ++++++
 arch/x86/kernel/entry_64.S              | 13 +++++++-
 arch/x86/kernel/head64.c                |  2 +-
 arch/x86/kernel/kvm.c                   |  2 +-
 arch/x86/kernel/traps.c                 | 28 ++++++++--------
 arch/x86/mm/Makefile                    |  2 ++
 arch/x86/mm/fault.c                     | 23 +++++++++++++
 12 files changed, 165 insertions(+), 50 deletions(-)
 create mode 100644 arch/x86/include/asm/trace/exceptions.h

-- 
1.8.3.1

[PATCH v4 1/4] Move set_intr_gate() into macro

[Seiji Aguchi]

Move set_intr_gate() into a macro by removing __alloc_intr_gate().

The purpose is to avoid failing a kernel build after applying
a subsequent patch which changes set_intr_gate() to macro.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
---
 arch/x86/include/asm/desc.h | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index b90e5df..d939567 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -395,15 +395,10 @@ static inline void trace_set_intr_gate(unsigned int gate, void *addr)
 #define __trace_alloc_intr_gate(n, addr)
 #endif
 
-static inline void __alloc_intr_gate(unsigned int n, void *addr)
-{
-	set_intr_gate(n, addr);
-}
-
 #define alloc_intr_gate(n, addr)				\
 	do {							\
 		alloc_system_vector(n);				\
-		__alloc_intr_gate(n, addr);			\
+		set_intr_gate(n, addr);				\
 		__trace_alloc_intr_gate(n, trace_##addr);	\
 	} while (0)
 
-- 
1.8.3.1

[PATCH v4 2/4] Register exception handler to trace IDT

[Seiji Aguchi]

This patch registers exception handlers for tracing to a trace IDT.

To implemented it in set_intr_gate(), this patch does followings.
 - Register the exception handlers to
   the trace IDT by prepending "trace_" to the handler's names.
 - Also, newly introduce trace_page_fault() to add tracepoints
   in a subsequent patch.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
---
 arch/x86/include/asm/desc.h    | 28 +++++++++++++++++++++++-----
 arch/x86/include/asm/hw_irq.h  |  3 +++
 arch/x86/include/asm/segment.h |  3 +++
 arch/x86/include/asm/traps.h   | 20 ++++++++++++++++++++
 arch/x86/kernel/entry_32.S     | 10 ++++++++++
 arch/x86/kernel/entry_64.S     | 13 ++++++++++++-
 arch/x86/kernel/head64.c       |  2 +-
 arch/x86/kernel/kvm.c          |  2 +-
 arch/x86/kernel/traps.c        | 28 ++++++++++++++--------------
 arch/x86/mm/fault.c            | 10 ++++++++++
 10 files changed, 97 insertions(+), 22 deletions(-)

diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index d939567..3d73437 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -327,10 +327,25 @@ static inline void write_trace_idt_entry(int entry, const gate_desc *gate)
 {
 	write_idt_entry(trace_idt_table, entry, gate);
 }
+
+static inline void _trace_set_gate(int gate, unsigned type, void *addr,
+				   unsigned dpl, unsigned ist, unsigned seg)
+{
+	gate_desc s;
+
+	pack_gate(&s, type, (unsigned long)addr, dpl, ist, seg);
+	/*
+	 * does not need to be atomic because it is only done once at
+	 * setup time
+	 */
+	write_trace_idt_entry(gate, &s);
+}
 #else
 static inline void write_trace_idt_entry(int entry, const gate_desc *gate)
 {
 }
+
+#define _trace_set_gate(gate, type, addr, dpl, ist, seg)
 #endif
 
 static inline void _set_gate(int gate, unsigned type, void *addr,
@@ -353,11 +368,14 @@ static inline void _set_gate(int gate, unsigned type, void *addr,
  * Pentium F0 0F bugfix can have resulted in the mapped
  * IDT being write-protected.
  */
-static inline void set_intr_gate(unsigned int n, void *addr)
-{
-	BUG_ON((unsigned)n > 0xFF);
-	_set_gate(n, GATE_INTERRUPT, addr, 0, 0, __KERNEL_CS);
-}
+#define set_intr_gate(n, addr)						\
+	do {								\
+		BUG_ON((unsigned)n > 0xFF);				\
+		_set_gate(n, GATE_INTERRUPT, (void *)addr, 0, 0,	\
+			  __KERNEL_CS);					\
+		_trace_set_gate(n, GATE_INTERRUPT, (void *)trace_##addr,\
+				0, 0, __KERNEL_CS);			\
+	} while (0)
 
 extern int first_system_vector;
 /* used_vectors is BITMAP for irq is not managed by percpu vector_irq */
diff --git a/arch/x86/include/asm/hw_irq.h b/arch/x86/include/asm/hw_irq.h
index 92b3bae..cba45d9 100644
--- a/arch/x86/include/asm/hw_irq.h
+++ b/arch/x86/include/asm/hw_irq.h
@@ -187,6 +187,9 @@ extern __visible void smp_invalidate_interrupt(struct pt_regs *);
 #endif
 
 extern void (*__initconst interrupt[NR_VECTORS-FIRST_EXTERNAL_VECTOR])(void);
+#ifdef CONFIG_TRACING
+#define trace_interrupt interrupt
+#endif
 
 typedef int vector_irq_t[NR_VECTORS];
 DECLARE_PER_CPU(vector_irq_t, vector_irq);
diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h
index c48a950..6f1c3a8 100644
--- a/arch/x86/include/asm/segment.h
+++ b/arch/x86/include/asm/segment.h
@@ -214,6 +214,9 @@
 #ifdef __KERNEL__
 #ifndef __ASSEMBLY__
 extern const char early_idt_handlers[NUM_EXCEPTION_VECTORS][2+2+5];
+#ifdef CONFIG_TRACING
+#define trace_early_idt_handlers early_idt_handlers
+#endif
 
 /*
  * Load a segment. Fall back on loading the zero
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index 7036cb6..58d66fe 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -37,6 +37,23 @@ asmlinkage void machine_check(void);
 #endif /* CONFIG_X86_MCE */
 asmlinkage void simd_coprocessor_error(void);
 
+#ifdef CONFIG_TRACING
+asmlinkage void trace_page_fault(void);
+#define trace_divide_error divide_error
+#define trace_bounds bounds
+#define trace_invalid_op invalid_op
+#define trace_device_not_available device_not_available
+#define trace_coprocessor_segment_overrun coprocessor_segment_overrun
+#define trace_invalid_TSS invalid_TSS
+#define trace_segment_not_present segment_not_present
+#define trace_general_protection general_protection
+#define trace_spurious_interrupt_bug spurious_interrupt_bug
+#define trace_coprocessor_error coprocessor_error
+#define trace_alignment_check alignment_check
+#define trace_simd_coprocessor_error simd_coprocessor_error
+#define trace_async_page_fault async_page_fault
+#endif
+
 dotraplinkage void do_divide_error(struct pt_regs *, long);
 dotraplinkage void do_debug(struct pt_regs *, long);
 dotraplinkage void do_nmi(struct pt_regs *, long);
@@ -55,6 +72,9 @@ asmlinkage __kprobes 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);
+#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/entry_32.S b/arch/x86/kernel/entry_32.S
index f0dcb0c..0661abe 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1247,6 +1247,16 @@ return_to_handler:
  */
 	.pushsection .kprobes.text, "ax"
 
+#ifdef CONFIG_TRACING
+ENTRY(trace_page_fault)
+	RING0_EC_FRAME
+	ASM_CLAC
+	pushl_cfi $trace_do_page_fault
+	jmp error_code
+	CFI_ENDPROC
+END(trace_page_fault)
+#endif
+
 ENTRY(page_fault)
 	RING0_EC_FRAME
 	ASM_CLAC
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index b077f4c..8b7b169 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1280,6 +1280,17 @@ ENTRY(\sym)
 END(\sym)
 .endm
 
+#ifdef CONFIG_TRACING
+.macro trace_errorentry sym do_sym
+errorentry trace(\sym) trace(\do_sym)
+errorentry \sym \do_sym
+.endm
+#else
+.macro trace_errorentry sym do_sym
+errorentry \sym \do_sym
+.endm
+#endif
+
 	/* error code is on the stack already */
 .macro paranoiderrorentry sym do_sym
 ENTRY(\sym)
@@ -1482,7 +1493,7 @@ zeroentry xen_int3 do_int3
 errorentry xen_stack_segment do_stack_segment
 #endif
 errorentry general_protection do_general_protection
-errorentry page_fault do_page_fault
+trace_errorentry page_fault do_page_fault
 #ifdef CONFIG_KVM_GUEST
 errorentry async_page_fault do_async_page_fault
 #endif
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 1be8e43..85126cc 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -162,7 +162,7 @@ asmlinkage void __init x86_64_start_kernel(char * real_mode_data)
 	clear_bss();
 
 	for (i = 0; i < NUM_EXCEPTION_VECTORS; i++)
-		set_intr_gate(i, &early_idt_handlers[i]);
+		set_intr_gate(i, early_idt_handlers[i]);
 	load_idt((const struct desc_ptr *)&idt_descr);
 
 	copy_bootdata(__va(real_mode_data));
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index a0e2a8a..028d7a4 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -464,7 +464,7 @@ static struct notifier_block kvm_cpu_notifier = {
 
 static void __init kvm_apf_trap_init(void)
 {
-	set_intr_gate(14, &async_page_fault);
+	set_intr_gate(14, async_page_fault);
 }
 
 void __init kvm_guest_init(void)
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 8c8093b..1c9d0ad 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -713,7 +713,7 @@ void __init early_trap_init(void)
 	/* int3 can be called from all */
 	set_system_intr_gate_ist(X86_TRAP_BP, &int3, DEBUG_STACK);
 #ifdef CONFIG_X86_32
-	set_intr_gate(X86_TRAP_PF, &page_fault);
+	set_intr_gate(X86_TRAP_PF, page_fault);
 #endif
 	load_idt(&idt_descr);
 }
@@ -721,7 +721,7 @@ void __init early_trap_init(void)
 void __init early_trap_pf_init(void)
 {
 #ifdef CONFIG_X86_64
-	set_intr_gate(X86_TRAP_PF, &page_fault);
+	set_intr_gate(X86_TRAP_PF, page_fault);
 #endif
 }
 
@@ -737,30 +737,30 @@ void __init trap_init(void)
 	early_iounmap(p, 4);
 #endif
 
-	set_intr_gate(X86_TRAP_DE, &divide_error);
+	set_intr_gate(X86_TRAP_DE, divide_error);
 	set_intr_gate_ist(X86_TRAP_NMI, &nmi, NMI_STACK);
 	/* int4 can be called from all */
 	set_system_intr_gate(X86_TRAP_OF, &overflow);
-	set_intr_gate(X86_TRAP_BR, &bounds);
-	set_intr_gate(X86_TRAP_UD, &invalid_op);
-	set_intr_gate(X86_TRAP_NM, &device_not_available);
+	set_intr_gate(X86_TRAP_BR, bounds);
+	set_intr_gate(X86_TRAP_UD, invalid_op);
+	set_intr_gate(X86_TRAP_NM, device_not_available);
 #ifdef CONFIG_X86_32
 	set_task_gate(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS);
 #else
 	set_intr_gate_ist(X86_TRAP_DF, &double_fault, DOUBLEFAULT_STACK);
 #endif
-	set_intr_gate(X86_TRAP_OLD_MF, &coprocessor_segment_overrun);
-	set_intr_gate(X86_TRAP_TS, &invalid_TSS);
-	set_intr_gate(X86_TRAP_NP, &segment_not_present);
+	set_intr_gate(X86_TRAP_OLD_MF, coprocessor_segment_overrun);
+	set_intr_gate(X86_TRAP_TS, invalid_TSS);
+	set_intr_gate(X86_TRAP_NP, segment_not_present);
 	set_intr_gate_ist(X86_TRAP_SS, &stack_segment, STACKFAULT_STACK);
-	set_intr_gate(X86_TRAP_GP, &general_protection);
-	set_intr_gate(X86_TRAP_SPURIOUS, &spurious_interrupt_bug);
-	set_intr_gate(X86_TRAP_MF, &coprocessor_error);
-	set_intr_gate(X86_TRAP_AC, &alignment_check);
+	set_intr_gate(X86_TRAP_GP, general_protection);
+	set_intr_gate(X86_TRAP_SPURIOUS, spurious_interrupt_bug);
+	set_intr_gate(X86_TRAP_MF, coprocessor_error);
+	set_intr_gate(X86_TRAP_AC, alignment_check);
 #ifdef CONFIG_X86_MCE
 	set_intr_gate_ist(X86_TRAP_MC, &machine_check, MCE_STACK);
 #endif
-	set_intr_gate(X86_TRAP_XF, &simd_coprocessor_error);
+	set_intr_gate(X86_TRAP_XF, simd_coprocessor_error);
 
 	/* Reserve all the builtin and the syscall vector: */
 	for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 3aaeffc..fd3e281 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1231,3 +1231,13 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code)
 	__do_page_fault(regs, error_code);
 	exception_exit(prev_state);
 }
+
+dotraplinkage void __kprobes
+trace_do_page_fault(struct pt_regs *regs, unsigned long error_code)
+{
+	enum ctx_state prev_state;
+
+	prev_state = exception_enter();
+	__do_page_fault(regs, error_code);
+	exception_exit(prev_state);
+}
-- 
1.8.3.1

[PATCH v4 3/4] Delete __trace_alloc_intr_gate()

[Seiji Aguchi]

Currently irq vector handlers for tracing are registered in both set_intr_gate()
 and __trace_alloc_intr_gate() in alloc_intr_gate().
But, we don't need to do that twice.
So, let's delete __trace_alloc_intr_gate().

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
---
 arch/x86/include/asm/desc.h | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index 3d73437..50d033a 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -392,32 +392,10 @@ static inline void alloc_system_vector(int vector)
 	}
 }
 
-#ifdef CONFIG_TRACING
-static inline void trace_set_intr_gate(unsigned int gate, void *addr)
-{
-	gate_desc s;
-
-	pack_gate(&s, GATE_INTERRUPT, (unsigned long)addr, 0, 0, __KERNEL_CS);
-	write_idt_entry(trace_idt_table, gate, &s);
-}
-
-static inline void __trace_alloc_intr_gate(unsigned int n, void *addr)
-{
-	trace_set_intr_gate(n, addr);
-}
-#else
-static inline void trace_set_intr_gate(unsigned int gate, void *addr)
-{
-}
-
-#define __trace_alloc_intr_gate(n, addr)
-#endif
-
 #define alloc_intr_gate(n, addr)				\
 	do {							\
 		alloc_system_vector(n);				\
 		set_intr_gate(n, addr);				\
-		__trace_alloc_intr_gate(n, trace_##addr);	\
 	} while (0)
 
 /*
-- 
1.8.3.1

[PATCH v4 4/4] Add page fault tracepoints

[Seiji Aguchi]

This patch introduces page fault tracepoints to x86 architecture
by switching IDT.

  Two events, for user and kernel spaces, are introduced at the beginning
  of page fault handler for tracing.

  - User space event
    There is a request of page fault event for user space as below.

    https://lkml.kernel.org/r/1368079520-11015-2-git-send-email-fdeslaur+()+gmail+!+com
    https://lkml.kernel.org/r/1368079520-11015-1-git-send-email-fdeslaur+()+gmail+!+com

  - Kernel space event:
    When we meature an overhead in kernel space for investigating performance
    issues, we can check if it comes from the page fault events.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
---
 arch/x86/include/asm/trace/exceptions.h | 52 +++++++++++++++++++++++++++++++++
 arch/x86/mm/Makefile                    |  2 ++
 arch/x86/mm/fault.c                     | 13 +++++++++
 3 files changed, 67 insertions(+)
 create mode 100644 arch/x86/include/asm/trace/exceptions.h

diff --git a/arch/x86/include/asm/trace/exceptions.h b/arch/x86/include/asm/trace/exceptions.h
new file mode 100644
index 0000000..86540c0
--- /dev/null
+++ b/arch/x86/include/asm/trace/exceptions.h
@@ -0,0 +1,52 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM exceptions
+
+#if !defined(_TRACE_PAGE_FAULT_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_PAGE_FAULT_H
+
+#include <linux/tracepoint.h>
+
+extern void trace_irq_vector_regfunc(void);
+extern void trace_irq_vector_unregfunc(void);
+
+DECLARE_EVENT_CLASS(x86_exceptions,
+
+	TP_PROTO(unsigned long address, struct pt_regs *regs,
+		 unsigned long error_code),
+
+	TP_ARGS(address, regs, error_code),
+
+	TP_STRUCT__entry(
+		__field(		unsigned long, address	)
+		__field(		unsigned long, ip	)
+		__field(		unsigned long, error_code )
+	),
+
+	TP_fast_assign(
+		__entry->address = address;
+		__entry->ip = regs->ip;
+		__entry->error_code = error_code;
+	),
+
+	TP_printk("address=%pf ip=%pf error_code=0x%lx",
+		  (void *)__entry->address, (void *)__entry->ip,
+		  __entry->error_code) );
+
+#define DEFINE_PAGE_FAULT_EVENT(name)				\
+DEFINE_EVENT_FN(x86_exceptions, name,				\
+	TP_PROTO(unsigned long address,	struct pt_regs *regs,	\
+		 unsigned long error_code),			\
+	TP_ARGS(address, regs, error_code),			\
+	trace_irq_vector_regfunc,				\
+	trace_irq_vector_unregfunc);
+
+DEFINE_PAGE_FAULT_EVENT(user_page_fault);
+DEFINE_PAGE_FAULT_EVENT(kernel_page_fault);
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#define TRACE_INCLUDE_FILE exceptions
+#endif /*  _TRACE_PAGE_FAULT_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
index 23d8e5f..6a19ad9 100644
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -6,6 +6,8 @@ nostackp := $(call cc-option, -fno-stack-protector)
 CFLAGS_physaddr.o		:= $(nostackp)
 CFLAGS_setup_nx.o		:= $(nostackp)
 
+CFLAGS_fault.o := -I$(src)/../include/asm/trace
+
 obj-$(CONFIG_X86_PAT)		+= pat_rbtree.o
 obj-$(CONFIG_SMP)		+= tlb.o
 
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index fd3e281..f2730cbc 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -20,6 +20,9 @@
 #include <asm/kmemcheck.h>		/* kmemcheck_*(), ...		*/
 #include <asm/fixmap.h>			/* VSYSCALL_START		*/
 
+#define CREATE_TRACE_POINTS
+#include <asm/trace/exceptions.h>
+
 /*
  * Page fault error code bits:
  *
@@ -1232,12 +1235,22 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code)
 	exception_exit(prev_state);
 }
 
+static void trace_page_fault_entries(struct pt_regs *regs,
+				     unsigned long error_code)
+{
+	if (user_mode(regs))
+		trace_user_page_fault(read_cr2(), regs, error_code);
+	else
+		trace_kernel_page_fault(read_cr2(), regs, error_code);
+}
+
 dotraplinkage void __kprobes
 trace_do_page_fault(struct pt_regs *regs, unsigned long error_code)
 {
 	enum ctx_state prev_state;
 
 	prev_state = exception_enter();
+	trace_page_fault_entries(regs, error_code);
 	__do_page_fault(regs, error_code);
 	exception_exit(prev_state);
 }
-- 
1.8.3.1

[tip:x86/trace] x86, trace: Remove __alloc_intr_gate()

[tip-bot for Seiji Aguchi]

Commit-ID:  959c071f0974cda7702d7574647de7ad9259eb57
Gitweb:     http://git.kernel.org/tip/959c071f0974cda7702d7574647de7ad9259eb57
Author:     Seiji Aguchi <seiji.aguchi@hds.com>
AuthorDate: Wed, 30 Oct 2013 16:36:08 -0400
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Fri, 8 Nov 2013 14:15:44 -0800

x86, trace: Remove __alloc_intr_gate()

Prepare to move set_intr_gate() into a macro by removing
__alloc_intr_gate().

The purpose is to avoid failing a kernel build after applying a
subsequent patch which changes set_intr_gate() into a macro.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/52716DB8.1080702@hds.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/include/asm/desc.h | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index b90e5df..d939567 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -395,15 +395,10 @@ static inline void trace_set_intr_gate(unsigned int gate, void *addr)
 #define __trace_alloc_intr_gate(n, addr)
 #endif
 
-static inline void __alloc_intr_gate(unsigned int n, void *addr)
-{
-	set_intr_gate(n, addr);
-}
-
 #define alloc_intr_gate(n, addr)				\
 	do {							\
 		alloc_system_vector(n);				\
-		__alloc_intr_gate(n, addr);			\
+		set_intr_gate(n, addr);				\
 		__trace_alloc_intr_gate(n, trace_##addr);	\
 	} while (0)
 

[tip:x86/trace] x86, trace: Register exception handler to trace IDT

[tip-bot for Seiji Aguchi]

Commit-ID:  25c74b10bacead867478480170083f69cfc0db48
Gitweb:     http://git.kernel.org/tip/25c74b10bacead867478480170083f69cfc0db48
Author:     Seiji Aguchi <seiji.aguchi@hds.com>
AuthorDate: Wed, 30 Oct 2013 16:37:00 -0400
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Fri, 8 Nov 2013 14:15:45 -0800

x86, trace: Register exception handler to trace IDT

This patch registers exception handlers for tracing to a trace IDT.

To implemented it in set_intr_gate(), this patch does followings.
 - Register the exception handlers to
   the trace IDT by prepending "trace_" to the handler's names.
 - Also, newly introduce trace_page_fault() to add tracepoints
   in a subsequent patch.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/52716DEC.5050204@hds.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/include/asm/desc.h    | 28 +++++++++++++++++++++++-----
 arch/x86/include/asm/hw_irq.h  |  3 +++
 arch/x86/include/asm/segment.h |  3 +++
 arch/x86/include/asm/traps.h   | 20 ++++++++++++++++++++
 arch/x86/kernel/entry_32.S     | 10 ++++++++++
 arch/x86/kernel/entry_64.S     | 13 ++++++++++++-
 arch/x86/kernel/head64.c       |  2 +-
 arch/x86/kernel/kvm.c          |  2 +-
 arch/x86/kernel/traps.c        | 28 ++++++++++++++--------------
 arch/x86/mm/fault.c            | 10 ++++++++++
 10 files changed, 97 insertions(+), 22 deletions(-)

diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index d939567..3d73437 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -327,10 +327,25 @@ static inline void write_trace_idt_entry(int entry, const gate_desc *gate)
 {
 	write_idt_entry(trace_idt_table, entry, gate);
 }
+
+static inline void _trace_set_gate(int gate, unsigned type, void *addr,
+				   unsigned dpl, unsigned ist, unsigned seg)
+{
+	gate_desc s;
+
+	pack_gate(&s, type, (unsigned long)addr, dpl, ist, seg);
+	/*
+	 * does not need to be atomic because it is only done once at
+	 * setup time
+	 */
+	write_trace_idt_entry(gate, &s);
+}
 #else
 static inline void write_trace_idt_entry(int entry, const gate_desc *gate)
 {
 }
+
+#define _trace_set_gate(gate, type, addr, dpl, ist, seg)
 #endif
 
 static inline void _set_gate(int gate, unsigned type, void *addr,
@@ -353,11 +368,14 @@ static inline void _set_gate(int gate, unsigned type, void *addr,
  * Pentium F0 0F bugfix can have resulted in the mapped
  * IDT being write-protected.
  */
-static inline void set_intr_gate(unsigned int n, void *addr)
-{
-	BUG_ON((unsigned)n > 0xFF);
-	_set_gate(n, GATE_INTERRUPT, addr, 0, 0, __KERNEL_CS);
-}
+#define set_intr_gate(n, addr)						\
+	do {								\
+		BUG_ON((unsigned)n > 0xFF);				\
+		_set_gate(n, GATE_INTERRUPT, (void *)addr, 0, 0,	\
+			  __KERNEL_CS);					\
+		_trace_set_gate(n, GATE_INTERRUPT, (void *)trace_##addr,\
+				0, 0, __KERNEL_CS);			\
+	} while (0)
 
 extern int first_system_vector;
 /* used_vectors is BITMAP for irq is not managed by percpu vector_irq */
diff --git a/arch/x86/include/asm/hw_irq.h b/arch/x86/include/asm/hw_irq.h
index 92b3bae..cba45d9 100644
--- a/arch/x86/include/asm/hw_irq.h
+++ b/arch/x86/include/asm/hw_irq.h
@@ -187,6 +187,9 @@ extern __visible void smp_invalidate_interrupt(struct pt_regs *);
 #endif
 
 extern void (*__initconst interrupt[NR_VECTORS-FIRST_EXTERNAL_VECTOR])(void);
+#ifdef CONFIG_TRACING
+#define trace_interrupt interrupt
+#endif
 
 typedef int vector_irq_t[NR_VECTORS];
 DECLARE_PER_CPU(vector_irq_t, vector_irq);
diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h
index c48a950..6f1c3a8 100644
--- a/arch/x86/include/asm/segment.h
+++ b/arch/x86/include/asm/segment.h
@@ -214,6 +214,9 @@
 #ifdef __KERNEL__
 #ifndef __ASSEMBLY__
 extern const char early_idt_handlers[NUM_EXCEPTION_VECTORS][2+2+5];
+#ifdef CONFIG_TRACING
+#define trace_early_idt_handlers early_idt_handlers
+#endif
 
 /*
  * Load a segment. Fall back on loading the zero
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h
index 7036cb6..58d66fe 100644
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -37,6 +37,23 @@ asmlinkage void machine_check(void);
 #endif /* CONFIG_X86_MCE */
 asmlinkage void simd_coprocessor_error(void);
 
+#ifdef CONFIG_TRACING
+asmlinkage void trace_page_fault(void);
+#define trace_divide_error divide_error
+#define trace_bounds bounds
+#define trace_invalid_op invalid_op
+#define trace_device_not_available device_not_available
+#define trace_coprocessor_segment_overrun coprocessor_segment_overrun
+#define trace_invalid_TSS invalid_TSS
+#define trace_segment_not_present segment_not_present
+#define trace_general_protection general_protection
+#define trace_spurious_interrupt_bug spurious_interrupt_bug
+#define trace_coprocessor_error coprocessor_error
+#define trace_alignment_check alignment_check
+#define trace_simd_coprocessor_error simd_coprocessor_error
+#define trace_async_page_fault async_page_fault
+#endif
+
 dotraplinkage void do_divide_error(struct pt_regs *, long);
 dotraplinkage void do_debug(struct pt_regs *, long);
 dotraplinkage void do_nmi(struct pt_regs *, long);
@@ -55,6 +72,9 @@ asmlinkage __kprobes 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);
+#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/entry_32.S b/arch/x86/kernel/entry_32.S
index f0dcb0c..0661abe 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1247,6 +1247,16 @@ return_to_handler:
  */
 	.pushsection .kprobes.text, "ax"
 
+#ifdef CONFIG_TRACING
+ENTRY(trace_page_fault)
+	RING0_EC_FRAME
+	ASM_CLAC
+	pushl_cfi $trace_do_page_fault
+	jmp error_code
+	CFI_ENDPROC
+END(trace_page_fault)
+#endif
+
 ENTRY(page_fault)
 	RING0_EC_FRAME
 	ASM_CLAC
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index b077f4c..8b7b169 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1280,6 +1280,17 @@ ENTRY(\sym)
 END(\sym)
 .endm
 
+#ifdef CONFIG_TRACING
+.macro trace_errorentry sym do_sym
+errorentry trace(\sym) trace(\do_sym)
+errorentry \sym \do_sym
+.endm
+#else
+.macro trace_errorentry sym do_sym
+errorentry \sym \do_sym
+.endm
+#endif
+
 	/* error code is on the stack already */
 .macro paranoiderrorentry sym do_sym
 ENTRY(\sym)
@@ -1482,7 +1493,7 @@ zeroentry xen_int3 do_int3
 errorentry xen_stack_segment do_stack_segment
 #endif
 errorentry general_protection do_general_protection
-errorentry page_fault do_page_fault
+trace_errorentry page_fault do_page_fault
 #ifdef CONFIG_KVM_GUEST
 errorentry async_page_fault do_async_page_fault
 #endif
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 1be8e43..85126cc 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -162,7 +162,7 @@ asmlinkage void __init x86_64_start_kernel(char * real_mode_data)
 	clear_bss();
 
 	for (i = 0; i < NUM_EXCEPTION_VECTORS; i++)
-		set_intr_gate(i, &early_idt_handlers[i]);
+		set_intr_gate(i, early_idt_handlers[i]);
 	load_idt((const struct desc_ptr *)&idt_descr);
 
 	copy_bootdata(__va(real_mode_data));
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index b2046e4..6dd802c 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -464,7 +464,7 @@ static struct notifier_block kvm_cpu_notifier = {
 
 static void __init kvm_apf_trap_init(void)
 {
-	set_intr_gate(14, &async_page_fault);
+	set_intr_gate(14, async_page_fault);
 }
 
 void __init kvm_guest_init(void)
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 8c8093b..1c9d0ad 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -713,7 +713,7 @@ void __init early_trap_init(void)
 	/* int3 can be called from all */
 	set_system_intr_gate_ist(X86_TRAP_BP, &int3, DEBUG_STACK);
 #ifdef CONFIG_X86_32
-	set_intr_gate(X86_TRAP_PF, &page_fault);
+	set_intr_gate(X86_TRAP_PF, page_fault);
 #endif
 	load_idt(&idt_descr);
 }
@@ -721,7 +721,7 @@ void __init early_trap_init(void)
 void __init early_trap_pf_init(void)
 {
 #ifdef CONFIG_X86_64
-	set_intr_gate(X86_TRAP_PF, &page_fault);
+	set_intr_gate(X86_TRAP_PF, page_fault);
 #endif
 }
 
@@ -737,30 +737,30 @@ void __init trap_init(void)
 	early_iounmap(p, 4);
 #endif
 
-	set_intr_gate(X86_TRAP_DE, &divide_error);
+	set_intr_gate(X86_TRAP_DE, divide_error);
 	set_intr_gate_ist(X86_TRAP_NMI, &nmi, NMI_STACK);
 	/* int4 can be called from all */
 	set_system_intr_gate(X86_TRAP_OF, &overflow);
-	set_intr_gate(X86_TRAP_BR, &bounds);
-	set_intr_gate(X86_TRAP_UD, &invalid_op);
-	set_intr_gate(X86_TRAP_NM, &device_not_available);
+	set_intr_gate(X86_TRAP_BR, bounds);
+	set_intr_gate(X86_TRAP_UD, invalid_op);
+	set_intr_gate(X86_TRAP_NM, device_not_available);
 #ifdef CONFIG_X86_32
 	set_task_gate(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS);
 #else
 	set_intr_gate_ist(X86_TRAP_DF, &double_fault, DOUBLEFAULT_STACK);
 #endif
-	set_intr_gate(X86_TRAP_OLD_MF, &coprocessor_segment_overrun);
-	set_intr_gate(X86_TRAP_TS, &invalid_TSS);
-	set_intr_gate(X86_TRAP_NP, &segment_not_present);
+	set_intr_gate(X86_TRAP_OLD_MF, coprocessor_segment_overrun);
+	set_intr_gate(X86_TRAP_TS, invalid_TSS);
+	set_intr_gate(X86_TRAP_NP, segment_not_present);
 	set_intr_gate_ist(X86_TRAP_SS, &stack_segment, STACKFAULT_STACK);
-	set_intr_gate(X86_TRAP_GP, &general_protection);
-	set_intr_gate(X86_TRAP_SPURIOUS, &spurious_interrupt_bug);
-	set_intr_gate(X86_TRAP_MF, &coprocessor_error);
-	set_intr_gate(X86_TRAP_AC, &alignment_check);
+	set_intr_gate(X86_TRAP_GP, general_protection);
+	set_intr_gate(X86_TRAP_SPURIOUS, spurious_interrupt_bug);
+	set_intr_gate(X86_TRAP_MF, coprocessor_error);
+	set_intr_gate(X86_TRAP_AC, alignment_check);
 #ifdef CONFIG_X86_MCE
 	set_intr_gate_ist(X86_TRAP_MC, &machine_check, MCE_STACK);
 #endif
-	set_intr_gate(X86_TRAP_XF, &simd_coprocessor_error);
+	set_intr_gate(X86_TRAP_XF, simd_coprocessor_error);
 
 	/* Reserve all the builtin and the syscall vector: */
 	for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 3aaeffc..fd3e281 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1231,3 +1231,13 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code)
 	__do_page_fault(regs, error_code);
 	exception_exit(prev_state);
 }
+
+dotraplinkage void __kprobes
+trace_do_page_fault(struct pt_regs *regs, unsigned long error_code)
+{
+	enum ctx_state prev_state;
+
+	prev_state = exception_enter();
+	__do_page_fault(regs, error_code);
+	exception_exit(prev_state);
+}

[tip:x86/trace] x86, trace: Delete __trace_alloc_intr_gate()

[tip-bot for Seiji Aguchi]

Commit-ID:  ac7956e2699380b8b10146ec2ba8cbe43a03ff7a
Gitweb:     http://git.kernel.org/tip/ac7956e2699380b8b10146ec2ba8cbe43a03ff7a
Author:     Seiji Aguchi <seiji.aguchi@hds.com>
AuthorDate: Wed, 30 Oct 2013 16:37:47 -0400
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Fri, 8 Nov 2013 14:15:47 -0800

x86, trace: Delete __trace_alloc_intr_gate()

Currently irq vector handlers for tracing are registered in both set_intr_gate()
 and __trace_alloc_intr_gate() in alloc_intr_gate().
But, we don't need to do that twice.
So, let's delete __trace_alloc_intr_gate().

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/52716E1B.7090205@hds.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/include/asm/desc.h | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index 3d73437..50d033a 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -392,32 +392,10 @@ static inline void alloc_system_vector(int vector)
 	}
 }
 
-#ifdef CONFIG_TRACING
-static inline void trace_set_intr_gate(unsigned int gate, void *addr)
-{
-	gate_desc s;
-
-	pack_gate(&s, GATE_INTERRUPT, (unsigned long)addr, 0, 0, __KERNEL_CS);
-	write_idt_entry(trace_idt_table, gate, &s);
-}
-
-static inline void __trace_alloc_intr_gate(unsigned int n, void *addr)
-{
-	trace_set_intr_gate(n, addr);
-}
-#else
-static inline void trace_set_intr_gate(unsigned int gate, void *addr)
-{
-}
-
-#define __trace_alloc_intr_gate(n, addr)
-#endif
-
 #define alloc_intr_gate(n, addr)				\
 	do {							\
 		alloc_system_vector(n);				\
 		set_intr_gate(n, addr);				\
-		__trace_alloc_intr_gate(n, trace_##addr);	\
 	} while (0)
 
 /*

[tip:x86/trace] x86, trace: Add page fault tracepoints

[tip-bot for Seiji Aguchi]

Commit-ID:  d34603b07c4255b2b00a546d34f297ccd50ae4c6
Gitweb:     http://git.kernel.org/tip/d34603b07c4255b2b00a546d34f297ccd50ae4c6
Author:     Seiji Aguchi <seiji.aguchi@hds.com>
AuthorDate: Wed, 30 Oct 2013 16:39:03 -0400
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Fri, 8 Nov 2013 14:15:49 -0800

x86, trace: Add page fault tracepoints

This patch introduces page fault tracepoints to x86 architecture
by switching IDT.

  Two events, for user and kernel spaces, are introduced at the beginning
  of page fault handler for tracing.

  - User space event
    There is a request of page fault event for user space as below.

    https://lkml.kernel.org/r/1368079520-11015-2-git-send-email-fdeslaur+()+gmail+!+com
    https://lkml.kernel.org/r/1368079520-11015-1-git-send-email-fdeslaur+()+gmail+!+com

  - Kernel space event:
    When we measure an overhead in kernel space for investigating performance
    issues, we can check if it comes from the page fault events.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/52716E67.6090705@hds.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/include/asm/trace/exceptions.h | 52 +++++++++++++++++++++++++++++++++
 arch/x86/mm/Makefile                    |  2 ++
 arch/x86/mm/fault.c                     | 13 +++++++++
 3 files changed, 67 insertions(+)

diff --git a/arch/x86/include/asm/trace/exceptions.h b/arch/x86/include/asm/trace/exceptions.h
new file mode 100644
index 0000000..86540c0
--- /dev/null
+++ b/arch/x86/include/asm/trace/exceptions.h
@@ -0,0 +1,52 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM exceptions
+
+#if !defined(_TRACE_PAGE_FAULT_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_PAGE_FAULT_H
+
+#include <linux/tracepoint.h>
+
+extern void trace_irq_vector_regfunc(void);
+extern void trace_irq_vector_unregfunc(void);
+
+DECLARE_EVENT_CLASS(x86_exceptions,
+
+	TP_PROTO(unsigned long address, struct pt_regs *regs,
+		 unsigned long error_code),
+
+	TP_ARGS(address, regs, error_code),
+
+	TP_STRUCT__entry(
+		__field(		unsigned long, address	)
+		__field(		unsigned long, ip	)
+		__field(		unsigned long, error_code )
+	),
+
+	TP_fast_assign(
+		__entry->address = address;
+		__entry->ip = regs->ip;
+		__entry->error_code = error_code;
+	),
+
+	TP_printk("address=%pf ip=%pf error_code=0x%lx",
+		  (void *)__entry->address, (void *)__entry->ip,
+		  __entry->error_code) );
+
+#define DEFINE_PAGE_FAULT_EVENT(name)				\
+DEFINE_EVENT_FN(x86_exceptions, name,				\
+	TP_PROTO(unsigned long address,	struct pt_regs *regs,	\
+		 unsigned long error_code),			\
+	TP_ARGS(address, regs, error_code),			\
+	trace_irq_vector_regfunc,				\
+	trace_irq_vector_unregfunc);
+
+DEFINE_PAGE_FAULT_EVENT(user_page_fault);
+DEFINE_PAGE_FAULT_EVENT(kernel_page_fault);
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#define TRACE_INCLUDE_FILE exceptions
+#endif /*  _TRACE_PAGE_FAULT_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
index 23d8e5f..6a19ad9 100644
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -6,6 +6,8 @@ nostackp := $(call cc-option, -fno-stack-protector)
 CFLAGS_physaddr.o		:= $(nostackp)
 CFLAGS_setup_nx.o		:= $(nostackp)
 
+CFLAGS_fault.o := -I$(src)/../include/asm/trace
+
 obj-$(CONFIG_X86_PAT)		+= pat_rbtree.o
 obj-$(CONFIG_SMP)		+= tlb.o
 
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index fd3e281..f2730cbc 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -20,6 +20,9 @@
 #include <asm/kmemcheck.h>		/* kmemcheck_*(), ...		*/
 #include <asm/fixmap.h>			/* VSYSCALL_START		*/
 
+#define CREATE_TRACE_POINTS
+#include <asm/trace/exceptions.h>
+
 /*
  * Page fault error code bits:
  *
@@ -1232,12 +1235,22 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code)
 	exception_exit(prev_state);
 }
 
+static void trace_page_fault_entries(struct pt_regs *regs,
+				     unsigned long error_code)
+{
+	if (user_mode(regs))
+		trace_user_page_fault(read_cr2(), regs, error_code);
+	else
+		trace_kernel_page_fault(read_cr2(), regs, error_code);
+}
+
 dotraplinkage void __kprobes
 trace_do_page_fault(struct pt_regs *regs, unsigned long error_code)
 {
 	enum ctx_state prev_state;
 
 	prev_state = exception_enter();
+	trace_page_fault_entries(regs, error_code);
 	__do_page_fault(regs, error_code);
 	exception_exit(prev_state);
 }

Re: [tip:x86/trace] x86, trace: Add page fault tracepoints

[Ingo Molnar]

* tip-bot for Seiji Aguchi <tipbot@zytor.com> wrote:

> Commit-ID:  d34603b07c4255b2b00a546d34f297ccd50ae4c6
> Gitweb:     http://git.kernel.org/tip/d34603b07c4255b2b00a546d34f297ccd50ae4c6
> Author:     Seiji Aguchi <seiji.aguchi@hds.com>
> AuthorDate: Wed, 30 Oct 2013 16:39:03 -0400
> Committer:  H. Peter Anvin <hpa@linux.intel.com>
> CommitDate: Fri, 8 Nov 2013 14:15:49 -0800
> 
> x86, trace: Add page fault tracepoints
> 
> This patch introduces page fault tracepoints to x86 architecture
> by switching IDT.
> 
>   Two events, for user and kernel spaces, are introduced at the beginning
>   of page fault handler for tracing.
> 
>   - User space event
>     There is a request of page fault event for user space as below.
> 
>     https://lkml.kernel.org/r/1368079520-11015-2-git-send-email-fdeslaur+()+gmail+!+com
>     https://lkml.kernel.org/r/1368079520-11015-1-git-send-email-fdeslaur+()+gmail+!+com
> 
>   - Kernel space event:
>     When we measure an overhead in kernel space for investigating performance
>     issues, we can check if it comes from the page fault events.
> 
> Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
> Link: http://lkml.kernel.org/r/52716E67.6090705@hds.com
> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
> ---
>  arch/x86/include/asm/trace/exceptions.h | 52 +++++++++++++++++++++++++++++++++
>  arch/x86/mm/Makefile                    |  2 ++
>  arch/x86/mm/fault.c                     | 13 +++++++++
>  3 files changed, 67 insertions(+)
> 
> diff --git a/arch/x86/include/asm/trace/exceptions.h b/arch/x86/include/asm/trace/exceptions.h
> new file mode 100644
> index 0000000..86540c0
> --- /dev/null
> +++ b/arch/x86/include/asm/trace/exceptions.h
> @@ -0,0 +1,52 @@
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM exceptions
> +
> +#if !defined(_TRACE_PAGE_FAULT_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_PAGE_FAULT_H
> +
> +#include <linux/tracepoint.h>
> +
> +extern void trace_irq_vector_regfunc(void);
> +extern void trace_irq_vector_unregfunc(void);
> +
> +DECLARE_EVENT_CLASS(x86_exceptions,
> +
> +	TP_PROTO(unsigned long address, struct pt_regs *regs,
> +		 unsigned long error_code),
> +
> +	TP_ARGS(address, regs, error_code),
> +
> +	TP_STRUCT__entry(
> +		__field(		unsigned long, address	)
> +		__field(		unsigned long, ip	)
> +		__field(		unsigned long, error_code )
> +	),
> +
> +	TP_fast_assign(
> +		__entry->address = address;
> +		__entry->ip = regs->ip;
> +		__entry->error_code = error_code;
> +	),
> +
> +	TP_printk("address=%pf ip=%pf error_code=0x%lx",
> +		  (void *)__entry->address, (void *)__entry->ip,
> +		  __entry->error_code) );
> +
> +#define DEFINE_PAGE_FAULT_EVENT(name)				\
> +DEFINE_EVENT_FN(x86_exceptions, name,				\
> +	TP_PROTO(unsigned long address,	struct pt_regs *regs,	\
> +		 unsigned long error_code),			\
> +	TP_ARGS(address, regs, error_code),			\
> +	trace_irq_vector_regfunc,				\
> +	trace_irq_vector_unregfunc);
> +
> +DEFINE_PAGE_FAULT_EVENT(user_page_fault);
> +DEFINE_PAGE_FAULT_EVENT(kernel_page_fault);

Nice!

It would be nice to change this to hierarchical naming:

   page_fault_user
   page_fault_kernel

I.e. the higher level concept named first and go to the left, details go 
to the right.

(That way x86_exceptions.page_fault_user has the names ordered correctly 
as well.)

Thanks,

	Ingo

Re: [tip:x86/trace] x86, trace: Add page fault tracepoints

[H. Peter Anvin]

On 11/11/2013 12:29 AM, Ingo Molnar wrote:
> 
> Nice!
> 
> It would be nice to change this to hierarchical naming:
> 
>    page_fault_user
>    page_fault_kernel
> 
> I.e. the higher level concept named first and go to the left, details go 
> to the right.
> 
> (That way x86_exceptions.page_fault_user has the names ordered correctly 
> as well.)
> 

Seiji - are you okay with this?  If so I'll just make a quick patch now.

	-hpa

RE: [tip:x86/trace] x86, trace: Add page fault tracepoints

[Seiji Aguchi]

> Seiji - are you okay with this?  If so I'll just make a quick patch now.
>

I'm OK with it.

Seiji

[tip:x86/trace] x86, trace: Change user|kernel_page_fault to page_fault_user|kernel

[tip-bot for H. Peter Anvin]

Commit-ID:  a4f61dec55c1bdebb84ba77212ebf98f7247736c
Gitweb:     http://git.kernel.org/tip/a4f61dec55c1bdebb84ba77212ebf98f7247736c
Author:     H. Peter Anvin <hpa@zytor.com>
AuthorDate: Mon, 11 Nov 2013 08:15:40 -0800
Committer:  H. Peter Anvin <hpa@zytor.com>
CommitDate: Mon, 11 Nov 2013 08:15:40 -0800

x86, trace: Change user|kernel_page_fault to page_fault_user|kernel

Tracepoints are named hierachially, and it makes more sense to keep a
general flow of information level from general to specific from left
to right, i.e.

	x86_exceptions.page_fault_user|kernel

rather than

	x86_exceptions.user|kernel_page_fault

Suggested-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Seiji Aguchi <seiji.aguchi@hds.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/20131111082955.GB12405@gmail.com
---
 arch/x86/include/asm/trace/exceptions.h | 4 ++--
 arch/x86/mm/fault.c                     | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/trace/exceptions.h b/arch/x86/include/asm/trace/exceptions.h
index 86540c0..2fbc66c 100644
--- a/arch/x86/include/asm/trace/exceptions.h
+++ b/arch/x86/include/asm/trace/exceptions.h
@@ -40,8 +40,8 @@ DEFINE_EVENT_FN(x86_exceptions, name,				\
 	trace_irq_vector_regfunc,				\
 	trace_irq_vector_unregfunc);
 
-DEFINE_PAGE_FAULT_EVENT(user_page_fault);
-DEFINE_PAGE_FAULT_EVENT(kernel_page_fault);
+DEFINE_PAGE_FAULT_EVENT(page_fault_user);
+DEFINE_PAGE_FAULT_EVENT(page_fault_kernel);
 
 #undef TRACE_INCLUDE_PATH
 #define TRACE_INCLUDE_PATH .
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index f2730cbc..e532230 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1239,9 +1239,9 @@ static void trace_page_fault_entries(struct pt_regs *regs,
 				     unsigned long error_code)
 {
 	if (user_mode(regs))
-		trace_user_page_fault(read_cr2(), regs, error_code);
+		trace_page_fault_user(read_cr2(), regs, error_code);
 	else
-		trace_kernel_page_fault(read_cr2(), regs, error_code);
+		trace_page_fault_kernel(read_cr2(), regs, error_code);
 }
 
 dotraplinkage void __kprobes

Re: [tip:x86/trace] x86, trace: Add page fault tracepoints

[Ingo Molnar]

* Seiji Aguchi <seiji.aguchi@hds.com> wrote:

> 
> > Seiji - are you okay with this?  If so I'll just make a quick patch now.
> >
> 
> I'm OK with it.

Thanks guys!

	Ingo