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| author | Steven Rostedt <srostedt@redhat.com> | 2011-08-16 09:57:10 -0400 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2012-04-27 21:10:44 -0400 |
| commit | 08d636b6d4fb80647fe8869ea1cd97b2c26a4751 (patch) | |
| tree | eb85c37e3a67e1c21df9b82e2d302d5d1899343a /arch/x86/include/asm/ftrace.h | |
| parent | 438ced1720b584000a9e8a4349d1f6bb7ee3ad6d (diff) | |
| download | linux-0-day-08d636b6d4fb80647fe8869ea1cd97b2c26a4751.tar.gz linux-0-day-08d636b6d4fb80647fe8869ea1cd97b2c26a4751.tar.xz | |
ftrace/x86: Have arch x86_64 use breakpoints instead of stop machine
This method changes x86 to add a breakpoint to the mcount locations
instead of calling stop machine.
Now that iret can be handled by NMIs, we perform the following to
update code:
1) Add a breakpoint to all locations that will be modified
2) Sync all cores
3) Update all locations to be either a nop or call (except breakpoint
op)
4) Sync all cores
5) Remove the breakpoint with the new code.
6) Sync all cores
[
Added updates that Masami suggested:
Use unlikely(modifying_ftrace_code) in int3 trap to keep kprobes efficient.
Don't use NOTIFY_* in ftrace handler in int3 as it is not a notifier.
]
Cc: H. Peter Anvin <hpa@zytor.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'arch/x86/include/asm/ftrace.h')
| -rw-r--r-- | arch/x86/include/asm/ftrace.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h index 268c783ab1c0e..18d9005d9e4f0 100644 --- a/arch/x86/include/asm/ftrace.h +++ b/arch/x86/include/asm/ftrace.h @@ -34,6 +34,7 @@ #ifndef __ASSEMBLY__ extern void mcount(void); +extern int modifying_ftrace_code; static inline unsigned long ftrace_call_adjust(unsigned long addr) { @@ -50,6 +51,8 @@ struct dyn_arch_ftrace { /* No extra data needed for x86 */ }; +int ftrace_int3_handler(struct pt_regs *regs); + #endif /* CONFIG_DYNAMIC_FTRACE */ #endif /* __ASSEMBLY__ */ #endif /* CONFIG_FUNCTION_TRACER */ |