diff options
Diffstat (limited to 'arch/mips')
| -rw-r--r-- | arch/mips/Makefile | 7 | ||||
| -rw-r--r-- | arch/mips/kernel/ftrace.c | 24 | ||||
| -rw-r--r-- | arch/mips/kernel/mcount.S | 14 |
3 files changed, 38 insertions, 7 deletions
diff --git a/arch/mips/Makefile b/arch/mips/Makefile index 3725ee9..d2c39fd 100644 --- a/arch/mips/Makefile +++ b/arch/mips/Makefile @@ -51,6 +51,13 @@ endif ifndef CONFIG_FUNCTION_TRACER cflags-y := -ffunction-sections endif +ifdef CONFIG_FUNCTION_GRAPH_TRACER + ifndef KBUILD_MCOUNT_RA_ADDRESS + ifeq ($(call cc-option-yn,-mmcount-ra-address), y) + cflags-y += -mmcount-ra-address -DKBUILD_MCOUNT_RA_ADDRESS + endif + endif +endif cflags-y += $(call cc-option, -mno-check-zero-division) ifdef CONFIG_32BIT diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c index e363fc6..68b0670 100644 --- a/arch/mips/kernel/ftrace.c +++ b/arch/mips/kernel/ftrace.c @@ -148,6 +148,7 @@ int ftrace_disable_ftrace_graph_caller(void) #endif /* !CONFIG_DYNAMIC_FTRACE */ +#ifndef KBUILD_MCOUNT_RA_ADDRESS #define S_RA_SP (0xafbf << 16) /* s{d,w} ra, offset(sp) */ #define S_R_SP (0xafb0 << 16) /* s{d,w} R, offset(sp) */ #define OFFSET_MASK 0xffff /* stack offset range: 0 ~ PT_SIZE */ @@ -201,6 +202,8 @@ unsigned long ftrace_get_parent_addr(unsigned long self_addr, return 0; } +#endif + /* * Hook the return address and push it in the stack of return addrs * in current thread info. @@ -218,19 +221,26 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, return; /* "parent" is the stack address saved the return address of the caller - * of _mcount, for a leaf function not save the return address in the - * stack address, so, we "emulate" one in _mcount's stack space, and - * hijack it directly, but for a non-leaf function, it will save the - * return address to the its stack space, so, we can not hijack the - * "parent" directly, but need to find the real stack address, + * of _mcount. + * + * if the gcc < 4.5, a leaf function does not save the return address + * in the stack address, so, we "emulate" one in _mcount's stack space, + * and hijack it directly, but for a non-leaf function, it save the + * return address to the its own stack space, we can not hijack it + * directly, but need to find the real stack address, * ftrace_get_parent_addr() does it! + * + * if gcc>= 4.5, with the new -mmcount-ra-address option, for a + * non-leaf function, the location of the return address will be saved + * to $12 for us, and for a leaf function, only put a zero into $12. we + * do it in ftrace_graph_caller of mcount.S. */ /* old = *parent; */ safe_load_stack(old, parent, faulted); if (unlikely(faulted)) goto out; - +#ifndef KBUILD_MCOUNT_RA_ADDRESS parent = (unsigned long *)ftrace_get_parent_addr(self_addr, old, (unsigned long)parent, fp); @@ -238,7 +248,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, * ra, stop function graph tracer and return */ if (parent == 0) goto out; - +#endif /* *parent = return_hooker; */ safe_store_stack(return_hooker, parent, faulted); if (unlikely(faulted)) diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S index 522e91c..0a9cfdb 100644 --- a/arch/mips/kernel/mcount.S +++ b/arch/mips/kernel/mcount.S @@ -70,6 +70,9 @@ _mcount: nop MCOUNT_SAVE_REGS +#ifdef KBUILD_MCOUNT_RA_ADDRESS + PTR_S t0, PT_R12(sp) /* t0 saved the location of the return address(at) by -mmcount-ra-address */ +#endif move a0, ra /* arg1: next ip, selfaddr */ .globl ftrace_call @@ -133,11 +136,22 @@ ftrace_stub: NESTED(ftrace_graph_caller, PT_SIZE, ra) #ifdef CONFIG_DYNAMIC_FTRACE PTR_L a1, PT_R31(sp) /* load the original ra from the stack */ +#ifdef KBUILD_MCOUNT_RA_ADDRESS + PTR_L t0, PT_R12(sp) /* load the original t0 from the stack */ +#endif #else MCOUNT_SAVE_REGS move a1, ra /* arg2: next ip, selfaddr */ #endif + +#ifdef KBUILD_MCOUNT_RA_ADDRESS + bnez t0, 1f /* non-leaf func: t0 saved the location of the return address */ + nop + PTR_LA t0, PT_R1(sp) /* leaf func: get the location of at(old ra) from our own stack */ +1: move a0, t0 /* arg1: the location of the return address */ +#else PTR_LA a0, PT_R1(sp) /* arg1: &AT -> a0 */ +#endif jal prepare_ftrace_return #ifdef CONFIG_FRAME_POINTER move a2, fp /* arg3: frame pointer */ |