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authorSteven Rostedt <srostedt@redhat.com>2011-08-16 17:57:10 +0400
committerSteven Rostedt <rostedt@goodmis.org>2012-04-28 05:10:44 +0400
commit08d636b6d4fb80647fe8869ea1cd97b2c26a4751 (patch)
treeeb85c37e3a67e1c21df9b82e2d302d5d1899343a /arch/x86/include/asm/ftrace.h
parent438ced1720b584000a9e8a4349d1f6bb7ee3ad6d (diff)
downloadlinux-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.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index 268c783ab1c0..18d9005d9e4f 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 */