diff options
| -rw-r--r-- | arch/x86/kernel/unwind_orc.c | 48 | ||||
| -rw-r--r-- | include/linux/ftrace.h | 2 | ||||
| -rw-r--r-- | kernel/trace/ftrace.c | 29 |
3 files changed, 66 insertions, 13 deletions
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index be86a865087a..1f9188f5357c 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -74,8 +74,50 @@ static struct orc_entry *orc_module_find(unsigned long ip) } #endif +#ifdef CONFIG_DYNAMIC_FTRACE +static struct orc_entry *orc_find(unsigned long ip); + +/* + * Ftrace dynamic trampolines do not have orc entries of their own. + * But they are copies of the ftrace entries that are static and + * defined in ftrace_*.S, which do have orc entries. + * + * If the undwinder comes across a ftrace trampoline, then find the + * ftrace function that was used to create it, and use that ftrace + * function's orc entrie, as the placement of the return code in + * the stack will be identical. + */ +static struct orc_entry *orc_ftrace_find(unsigned long ip) +{ + struct ftrace_ops *ops; + unsigned long caller; + + ops = ftrace_ops_trampoline(ip); + if (!ops) + return NULL; + + if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) + caller = (unsigned long)ftrace_regs_call; + else + caller = (unsigned long)ftrace_call; + + /* Prevent unlikely recursion */ + if (ip == caller) + return NULL; + + return orc_find(caller); +} +#else +static struct orc_entry *orc_ftrace_find(unsigned long ip) +{ + return NULL; +} +#endif + static struct orc_entry *orc_find(unsigned long ip) { + static struct orc_entry *orc; + if (!orc_init) return NULL; @@ -111,7 +153,11 @@ static struct orc_entry *orc_find(unsigned long ip) __stop_orc_unwind_ip - __start_orc_unwind_ip, ip); /* Module lookup: */ - return orc_module_find(ip); + orc = orc_module_find(ip); + if (orc) + return orc; + + return orc_ftrace_find(ip); } static void orc_sort_swap(void *_a, void *_b, int size) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 2bab81951ced..3319df9727aa 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -332,6 +332,8 @@ extern int ftrace_text_reserved(const void *start, const void *end); extern int ftrace_nr_registered_ops(void); +struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr); + bool is_ftrace_trampoline(unsigned long addr); /* diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index ccdf3664e4a9..554b517c61a0 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1119,15 +1119,11 @@ static struct ftrace_ops global_ops = { }; /* - * This is used by __kernel_text_address() to return true if the - * address is on a dynamically allocated trampoline that would - * not return true for either core_kernel_text() or - * is_module_text_address(). + * Used by the stack undwinder to know about dynamic ftrace trampolines. */ -bool is_ftrace_trampoline(unsigned long addr) +struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr) { - struct ftrace_ops *op; - bool ret = false; + struct ftrace_ops *op = NULL; /* * Some of the ops may be dynamically allocated, @@ -1144,15 +1140,24 @@ bool is_ftrace_trampoline(unsigned long addr) if (op->trampoline && op->trampoline_size) if (addr >= op->trampoline && addr < op->trampoline + op->trampoline_size) { - ret = true; - goto out; + preempt_enable_notrace(); + return op; } } while_for_each_ftrace_op(op); - - out: preempt_enable_notrace(); - return ret; + return NULL; +} + +/* + * This is used by __kernel_text_address() to return true if the + * address is on a dynamically allocated trampoline that would + * not return true for either core_kernel_text() or + * is_module_text_address(). + */ +bool is_ftrace_trampoline(unsigned long addr) +{ + return ftrace_ops_trampoline(addr) != NULL; } struct ftrace_page { |