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x86, trace: Add page fault tracepoints

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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>
This commit is contained in:
Seiji Aguchi 2013-10-30 16:39:03 -04:00 committed by H. Peter Anvin
parent ac7956e269
commit d34603b07c
3 changed files with 67 additions and 0 deletions
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52
arch/x86/include/asm/trace/exceptions.h Normal file
View File

@ -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>

2
arch/x86/mm/Makefile
View File

@ -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

13
arch/x86/mm/fault.c
View File

@ -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);
}