diff options
Diffstat (limited to 'arch/arm/kernel/ftrace.c')
| -rw-r--r-- | arch/arm/kernel/ftrace.c | 103 |
1 files changed, 98 insertions, 5 deletions
diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c index 971ac8c36ea..c0062ad1e84 100644 --- a/arch/arm/kernel/ftrace.c +++ b/arch/arm/kernel/ftrace.c @@ -24,6 +24,7 @@ #define NOP 0xe8bd4000 /* pop {lr} */ #endif +#ifdef CONFIG_DYNAMIC_FTRACE #ifdef CONFIG_OLD_MCOUNT #define OLD_MCOUNT_ADDR ((unsigned long) mcount) #define OLD_FTRACE_ADDR ((unsigned long) ftrace_caller_old) @@ -59,9 +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; @@ -83,15 +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 @@ -103,10 +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) { @@ -193,3 +206,83 @@ int __init ftrace_dyn_arch_init(void *data) return 0; } +#endif /* CONFIG_DYNAMIC_FTRACE */ + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, + unsigned long frame_pointer) +{ + unsigned long return_hooker = (unsigned long) &return_to_handler; + struct ftrace_graph_ent trace; + unsigned long old; + int err; + + if (unlikely(atomic_read(¤t->tracing_graph_pause))) + return; + + old = *parent; + *parent = return_hooker; + + err = ftrace_push_return_trace(old, self_addr, &trace.depth, + frame_pointer); + if (err == -EBUSY) { + *parent = old; + return; + } + + trace.func = self_addr; + + /* Only trace if the calling function expects to */ + if (!ftrace_graph_entry(&trace)) { + current->curr_ret_stack--; + *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 */ |