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author | Rabin Vincent <rabin@rab.in> | 2010-11-06 23:03:21 +0530 |
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committer | Rabin Vincent <rabin@rab.in> | 2010-11-19 21:43:27 +0530 |
commit | dd686eb13959e49a1112fd608c124ab711050582 (patch) | |
tree | 58dfcbac57ace3dcb449593ca333b98c147a2410 /arch/arm/kernel | |
parent | 376cfa8730c08c0394d0aa1d4a80fd8c9971f323 (diff) | |
download | op-kernel-dev-dd686eb13959e49a1112fd608c124ab711050582.zip op-kernel-dev-dd686eb13959e49a1112fd608c124ab711050582.tar.gz |
ARM: ftrace: graph tracer + dynamic ftrace
Support the graph tracer + dynamic ftrace combination on ARM.
Signed-off-by: Rabin Vincent <rabin@rab.in>
Diffstat (limited to 'arch/arm/kernel')
-rw-r--r-- | arch/arm/kernel/entry-common.S | 12 | ||||
-rw-r--r-- | arch/arm/kernel/ftrace.c | 69 |
2 files changed, 76 insertions, 5 deletions
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index 9f17662..aae802e 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -183,12 +183,24 @@ ENDPROC(ret_from_fork) ftrace_call\suffix: bl ftrace_stub +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + .globl ftrace_graph_call\suffix +ftrace_graph_call\suffix: + mov r0, r0 +#endif + mcount_exit .endm .macro __ftrace_graph_caller sub r0, fp, #4 @ &lr of instrumented routine (&parent) +#ifdef CONFIG_DYNAMIC_FTRACE + @ called from __ftrace_caller, saved in mcount_enter + ldr r1, [sp, #16] @ instrumented routine (func) +#else + @ called from __mcount, untouched in lr mov r1, lr @ instrumented routine (func) +#endif sub r1, r1, #MCOUNT_INSN_SIZE mov r2, fp @ frame pointer bl prepare_ftrace_return diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c index 7a702a5..c0062ad 100644 --- a/arch/arm/kernel/ftrace.c +++ b/arch/arm/kernel/ftrace.c @@ -60,9 +60,9 @@ static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr) } #endif -/* construct a branch (BL) instruction to addr */ #ifdef CONFIG_THUMB2_KERNEL -static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr) +static unsigned long ftrace_gen_branch(unsigned long pc, unsigned long addr, + bool link) { unsigned long s, j1, j2, i1, i2, imm10, imm11; unsigned long first, second; @@ -84,15 +84,22 @@ static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr) j2 = (!i2) ^ s; first = 0xf000 | (s << 10) | imm10; - second = 0xd000 | (j1 << 13) | (j2 << 11) | imm11; + second = 0x9000 | (j1 << 13) | (j2 << 11) | imm11; + if (link) + second |= 1 << 14; return (second << 16) | first; } #else -static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr) +static unsigned long ftrace_gen_branch(unsigned long pc, unsigned long addr, + bool link) { + unsigned long opcode = 0xea000000; long offset; + if (link) + opcode |= 1 << 24; + offset = (long)addr - (long)(pc + 8); if (unlikely(offset < -33554432 || offset > 33554428)) { /* Can't generate branches that far (from ARM ARM). Ftrace @@ -104,10 +111,15 @@ static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr) offset = (offset >> 2) & 0x00ffffff; - return 0xeb000000 | offset; + return opcode | offset; } #endif +static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr) +{ + return ftrace_gen_branch(pc, addr, true); +} + static int ftrace_modify_code(unsigned long pc, unsigned long old, unsigned long new) { @@ -226,4 +238,51 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, *parent = old; } } + +#ifdef CONFIG_DYNAMIC_FTRACE +extern unsigned long ftrace_graph_call; +extern unsigned long ftrace_graph_call_old; +extern void ftrace_graph_caller_old(void); + +static int __ftrace_modify_caller(unsigned long *callsite, + void (*func) (void), bool enable) +{ + unsigned long caller_fn = (unsigned long) func; + unsigned long pc = (unsigned long) callsite; + unsigned long branch = ftrace_gen_branch(pc, caller_fn, false); + unsigned long nop = 0xe1a00000; /* mov r0, r0 */ + unsigned long old = enable ? nop : branch; + unsigned long new = enable ? branch : nop; + + return ftrace_modify_code(pc, old, new); +} + +static int ftrace_modify_graph_caller(bool enable) +{ + int ret; + + ret = __ftrace_modify_caller(&ftrace_graph_call, + ftrace_graph_caller, + enable); + +#ifdef CONFIG_OLD_MCOUNT + if (!ret) + ret = __ftrace_modify_caller(&ftrace_graph_call_old, + ftrace_graph_caller_old, + enable); +#endif + + return ret; +} + +int ftrace_enable_ftrace_graph_caller(void) +{ + return ftrace_modify_graph_caller(true); +} + +int ftrace_disable_ftrace_graph_caller(void) +{ + return ftrace_modify_graph_caller(false); +} +#endif /* CONFIG_DYNAMIC_FTRACE */ #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |