diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/mips/kernel/ftrace.c | 48 |
1 files changed, 26 insertions, 22 deletions
diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c index c4042cad836e..628e90b992d1 100644 --- a/arch/mips/kernel/ftrace.c +++ b/arch/mips/kernel/ftrace.c @@ -146,7 +146,7 @@ int __init ftrace_dyn_arch_init(void *data) return 0; } -#endif /* CONFIG_DYNAMIC_FTRACE */ +#endif /* CONFIG_DYNAMIC_FTRACE */ #ifdef CONFIG_FUNCTION_GRAPH_TRACER @@ -166,9 +166,10 @@ int ftrace_disable_ftrace_graph_caller(void) return ftrace_modify_code(FTRACE_GRAPH_CALL_IP, INSN_NOP); } -#endif /* !CONFIG_DYNAMIC_FTRACE */ +#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 */ @@ -182,17 +183,17 @@ unsigned long ftrace_get_parent_addr(unsigned long self_addr, unsigned int code; int faulted; - /* in module or kernel? */ - if (self_addr & 0x40000000) { - /* module: move to the instruction "lui v1, HI_16BIT_OF_MCOUNT" */ - ip = self_addr - 20; - } else { - /* kernel: move to the instruction "move ra, at" */ - ip = self_addr - 12; - } + /* + * For module, move the ip from calling site of mcount to the + * instruction "lui v1, hi_16bit_of_mcount"(offset is 20), but for + * kernel, move to the instruction "move ra, at"(offset is 12) + */ + ip = self_addr - ((self_addr & 0x40000000) ? 20 : 12); - /* search the text until finding the non-store instruction or "s{d,w} - * ra, offset(sp)" instruction */ + /* + * search the text until finding the non-store instruction or "s{d,w} + * ra, offset(sp)" instruction + */ do { ip -= 4; @@ -201,10 +202,11 @@ unsigned long ftrace_get_parent_addr(unsigned long self_addr, if (unlikely(faulted)) return 0; - - /* If we hit the non-store instruction before finding where the + /* + * If we hit the non-store instruction before finding where the * ra is stored, then this is a leaf function and it does not - * store the ra on the stack. */ + * store the ra on the stack + */ if ((code & S_R_SP) != S_R_SP) return parent_addr; @@ -222,7 +224,7 @@ unsigned long ftrace_get_parent_addr(unsigned long self_addr, return 0; } -#endif +#endif /* !KBUILD_MCOUNT_RA_ADDRESS */ /* * Hook the return address and push it in the stack of return addrs @@ -240,7 +242,8 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, if (unlikely(atomic_read(¤t->tracing_graph_pause))) return; - /* "parent" is the stack address saved the return address of the caller + /* + * "parent" is the stack address saved the return address of the caller * of _mcount. * * if the gcc < 4.5, a leaf function does not save the return address @@ -262,10 +265,11 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, goto out; #ifndef KBUILD_MCOUNT_RA_ADDRESS parent = (unsigned long *)ftrace_get_parent_addr(self_addr, old, - (unsigned long)parent, - fp); - /* If fails when getting the stack address of the non-leaf function's - * ra, stop function graph tracer and return */ + (unsigned long)parent, fp); + /* + * If fails when getting the stack address of the non-leaf function's + * ra, stop function graph tracer and return + */ if (parent == 0) goto out; #endif @@ -292,4 +296,4 @@ out: ftrace_graph_stop(); WARN_ON(1); } -#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |