From: "Steven Rostedt (Red Hat)" Linus pointed out that there were locations that did the hard coded update of the parent and rip parameters. One of them was the static tracer which could also use the ftrace_caller_setup to do that work. In fact, because it did not use it, it is prone to bugs, and since the static tracer is hardly ever used (who wants function tracing code always being called?) it doesn't get tested very often. I only run a few "does it still work" tests on it. But I do not run stress tests on that code. Although, since it is never turned off, just having it on should be stressful enough. (especially for the performance folks) There's no reason that the static tracer can't also use ftrace_caller_setup. Have it do so. Link: http://lkml.kernel.org/r/CA+55aFwF+qCGSKdGaEgW4p6N65GZ5_XTV=1NbtWDvxnd5yYLiw@mail.gmail.com Signed-off-by: Steven Rostedt --- arch/x86/kernel/mcount_64.S | 22 +++++++--------------- 1 file changed, 7 insertions(+), 15 deletions(-) diff --git a/arch/x86/kernel/mcount_64.S b/arch/x86/kernel/mcount_64.S index 6dc134b8dc70..24842c701660 100644 --- a/arch/x86/kernel/mcount_64.S +++ b/arch/x86/kernel/mcount_64.S @@ -21,12 +21,6 @@ # define function_hook mcount #endif -#ifdef CONFIG_DYNAMIC_FTRACE - -ENTRY(function_hook) - retq -END(function_hook) - /* skip is set if stack has been adjusted */ .macro ftrace_caller_setup trace_label skip=0 MCOUNT_SAVE_FRAME \skip @@ -47,6 +41,12 @@ GLOBAL(\trace_label) #endif .endm +#ifdef CONFIG_DYNAMIC_FTRACE + +ENTRY(function_hook) + retq +END(function_hook) + #ifdef CONFIG_FRAME_POINTER /* * Stack traces will stop at the ftrace trampoline if the frame pointer @@ -207,15 +207,7 @@ GLOBAL(ftrace_stub) retq trace: - MCOUNT_SAVE_FRAME - - movq RIP(%rsp), %rdi -#ifdef CC_USING_FENTRY - movq SS+16(%rsp), %rsi -#else - movq 8(%rbp), %rsi -#endif - subq $MCOUNT_INSN_SIZE, %rdi + ftrace_caller_setup ftrace_caller_op_ptr call *ftrace_trace_function -- 2.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/