From: Steven Rostedt <rost...@goodmis.org> Allow ftrace handlers to change RIP register (regs->ip) in handlers. This will allow handlers to call another function instead of original function.
Link: http://lkml.kernel.org/r/20120905143118.10329.5078.stgit@localhost.localdomain Cc: Peter Zijlstra <a.p.zijls...@chello.nl> Cc: Frederic Weisbecker <fweis...@gmail.com> Cc: Thomas Gleixner <t...@linutronix.de> Cc: "H. Peter Anvin" <h...@zytor.com> Signed-off-by: Masami Hiramatsu <masami.hiramatsu...@hitachi.com> Signed-off-by: Steven Rostedt <rost...@goodmis.org> --- arch/x86/kernel/entry_64.S | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index ed767b7..e9cc2b3 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -165,6 +165,10 @@ GLOBAL(ftrace_regs_call) movq EFLAGS(%rsp), %rax movq %rax, SS(%rsp) + /* Handlers can change the RIP */ + movq RIP(%rsp), %rax + movq %rax, SS+8(%rsp) + /* restore the rest of pt_regs */ movq R15(%rsp), %r15 movq R14(%rsp), %r14 -- 1.7.10.4
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