From 620176f335017fbfcbc79d26a8c9beb6e64f4868 Mon Sep 17 00:00:00 2001 From: Abel Vesa Date: Fri, 26 May 2017 21:49:47 +0100 Subject: ARM: 8678/1: ftrace: Adds support for CONFIG_DYNAMIC_FTRACE_WITH_REGS The DYNAMIC_FTRACE_WITH_REGS configuration makes it possible for a ftrace operation to specify if registers need to saved/restored by the ftrace handler. This is needed by kgraft and possibly other ftrace-based tools, and the ARM architecture is currently lacking this feature. It would also be the first step to support the "Kprobes-on-ftrace" optimization on ARM. This patch introduces a new ftrace handler that stores the registers on the stack before calling the next stage. The registers are restored from the stack before going back to the instrumented function. A side-effect of this patch is to activate the support for ftrace_modify_call() as it defines ARCH_SUPPORTS_FTRACE_OPS for the ARM architecture. Signed-off-by: Abel Vesa Signed-off-by: Russell King --- arch/arm/include/asm/ftrace.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/arm/include/asm/ftrace.h') diff --git a/arch/arm/include/asm/ftrace.h b/arch/arm/include/asm/ftrace.h index 22b73112b75f..f379881d5cc3 100644 --- a/arch/arm/include/asm/ftrace.h +++ b/arch/arm/include/asm/ftrace.h @@ -1,6 +1,10 @@ #ifndef _ASM_ARM_FTRACE #define _ASM_ARM_FTRACE +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS +#define ARCH_SUPPORTS_FTRACE_OPS 1 +#endif + #ifdef CONFIG_FUNCTION_TRACER #define MCOUNT_ADDR ((unsigned long)(__gnu_mcount_nc)) #define MCOUNT_INSN_SIZE 4 /* sizeof mcount call */ -- cgit