diff options
| -rw-r--r-- | arch/x86/kernel/ftrace.c | 98 | ||||
| -rw-r--r-- | kernel/trace/ftrace.c | 22 |
2 files changed, 106 insertions, 14 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index e4d48f6cad86..ca17c20a1010 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -48,7 +48,7 @@ int ftrace_arch_code_modify_post_process(void) union ftrace_code_union { char code[MCOUNT_INSN_SIZE]; struct { - char e8; + unsigned char e8; int offset; } __attribute__((packed)); }; @@ -797,12 +797,26 @@ static unsigned long create_trampoline(struct ftrace_ops *ops) return (unsigned long)trampoline; } +static unsigned long calc_trampoline_call_offset(bool save_regs) +{ + unsigned long start_offset; + unsigned long call_offset; + + if (save_regs) { + start_offset = (unsigned long)ftrace_regs_caller; + call_offset = (unsigned long)ftrace_regs_call; + } else { + start_offset = (unsigned long)ftrace_caller; + call_offset = (unsigned long)ftrace_call; + } + + return call_offset - start_offset; +} + void arch_ftrace_update_trampoline(struct ftrace_ops *ops) { ftrace_func_t func; unsigned char *new; - unsigned long start_offset; - unsigned long call_offset; unsigned long offset; unsigned long ip; int ret; @@ -820,15 +834,7 @@ void arch_ftrace_update_trampoline(struct ftrace_ops *ops) return; } - if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) { - start_offset = (unsigned long)ftrace_regs_caller; - call_offset = (unsigned long)ftrace_regs_call; - } else { - start_offset = (unsigned long)ftrace_caller; - call_offset = (unsigned long)ftrace_call; - } - - offset = call_offset - start_offset; + offset = calc_trampoline_call_offset(ops->flags & FTRACE_OPS_FL_SAVE_REGS); ip = ops->trampoline + offset; func = ftrace_ops_get_func(ops); @@ -840,6 +846,74 @@ void arch_ftrace_update_trampoline(struct ftrace_ops *ops) /* The update should never fail */ WARN_ON(ret); } + +/* Return the address of the function the trampoline calls */ +static void *addr_from_call(void *ptr) +{ + union ftrace_code_union calc; + int ret; + + ret = probe_kernel_read(&calc, ptr, MCOUNT_INSN_SIZE); + if (WARN_ON_ONCE(ret < 0)) + return NULL; + + /* Make sure this is a call */ + if (WARN_ON_ONCE(calc.e8 != 0xe8)) { + pr_warn("Expected e8, got %x\n", calc.e8); + return NULL; + } + + return ptr + MCOUNT_INSN_SIZE + calc.offset; +} + +void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, + unsigned long frame_pointer); + +/* + * If the ops->trampoline was not allocated, then it probably + * has a static trampoline func, or is the ftrace caller itself. + */ +static void *static_tramp_func(struct ftrace_ops *ops, struct dyn_ftrace *rec) +{ + unsigned long offset; + bool save_regs = rec->flags & FTRACE_FL_REGS_EN; + void *ptr; + + if (ops && ops->trampoline) { +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + /* + * We only know about function graph tracer setting as static + * trampoline. + */ + if (ops->trampoline == FTRACE_GRAPH_ADDR) + return (void *)prepare_ftrace_return; +#endif + return NULL; + } + + offset = calc_trampoline_call_offset(save_regs); + + if (save_regs) + ptr = (void *)FTRACE_REGS_ADDR + offset; + else + ptr = (void *)FTRACE_ADDR + offset; + + return addr_from_call(ptr); +} + +void *arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec) +{ + unsigned long offset; + + /* If we didn't allocate this trampoline, consider it static */ + if (!ops || !(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) + return static_tramp_func(ops, rec); + + offset = calc_trampoline_call_offset(ops->flags & FTRACE_OPS_FL_SAVE_REGS); + return addr_from_call((void *)ops->trampoline + offset); +} + + #endif /* CONFIG_X86_64 */ #endif /* CONFIG_DYNAMIC_FTRACE */ diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 15f85eac7e95..422e1f8300b1 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2952,6 +2952,22 @@ static void t_stop(struct seq_file *m, void *p) mutex_unlock(&ftrace_lock); } +void * __weak +arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec) +{ + return NULL; +} + +static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops, + struct dyn_ftrace *rec) +{ + void *ptr; + + ptr = arch_ftrace_trampoline_func(ops, rec); + if (ptr) + seq_printf(m, " ->%pS", ptr); +} + static int t_show(struct seq_file *m, void *v) { struct ftrace_iterator *iter = m->private; @@ -2975,19 +2991,21 @@ static int t_show(struct seq_file *m, void *v) seq_printf(m, "%ps", (void *)rec->ip); if (iter->flags & FTRACE_ITER_ENABLED) { + struct ftrace_ops *ops = NULL; + seq_printf(m, " (%ld)%s", ftrace_rec_count(rec), rec->flags & FTRACE_FL_REGS ? " R" : " "); if (rec->flags & FTRACE_FL_TRAMP_EN) { - struct ftrace_ops *ops; - ops = ftrace_find_tramp_ops_any(rec); if (ops) seq_printf(m, "\ttramp: %pS", (void *)ops->trampoline); else seq_printf(m, "\ttramp: ERROR!"); + } + add_trampoline_func(m, ops, rec); } seq_printf(m, "\n"); |