| /** |
| * @file backtrace.c |
| * |
| * @remark Copyright 2002 OProfile authors |
| * @remark Read the file COPYING |
| * |
| * @author John Levon |
| * @author David Smith |
| */ |
| |
| #include <linux/oprofile.h> |
| #include <linux/sched.h> |
| #include <linux/mm.h> |
| #include <asm/ptrace.h> |
| #include <asm/uaccess.h> |
| #include <asm/stacktrace.h> |
| |
| static void backtrace_warning_symbol(void *data, char *msg, |
| unsigned long symbol) |
| { |
| /* Ignore warnings */ |
| } |
| |
| static void backtrace_warning(void *data, char *msg) |
| { |
| /* Ignore warnings */ |
| } |
| |
| static int backtrace_stack(void *data, char *name) |
| { |
| /* Yes, we want all stacks */ |
| return 0; |
| } |
| |
| static void backtrace_address(void *data, unsigned long addr) |
| { |
| unsigned int *depth = data; |
| |
| if ((*depth)--) |
| oprofile_add_trace(addr); |
| } |
| |
| static struct stacktrace_ops backtrace_ops = { |
| .warning = backtrace_warning, |
| .warning_symbol = backtrace_warning_symbol, |
| .stack = backtrace_stack, |
| .address = backtrace_address, |
| }; |
| |
| struct frame_head { |
| struct frame_head *bp; |
| unsigned long ret; |
| } __attribute__((packed)); |
| |
| static struct frame_head * |
| dump_user_backtrace(struct frame_head * head) |
| { |
| struct frame_head bufhead[2]; |
| |
| /* Also check accessibility of one struct frame_head beyond */ |
| if (!access_ok(VERIFY_READ, head, sizeof(bufhead))) |
| return NULL; |
| if (__copy_from_user_inatomic(bufhead, head, sizeof(bufhead))) |
| return NULL; |
| |
| oprofile_add_trace(bufhead[0].ret); |
| |
| /* frame pointers should strictly progress back up the stack |
| * (towards higher addresses) */ |
| if (head >= bufhead[0].bp) |
| return NULL; |
| |
| return bufhead[0].bp; |
| } |
| |
| void |
| x86_backtrace(struct pt_regs * const regs, unsigned int depth) |
| { |
| struct frame_head *head = (struct frame_head *)frame_pointer(regs); |
| unsigned long stack = stack_pointer(regs); |
| |
| if (!user_mode_vm(regs)) { |
| if (depth) |
| dump_trace(NULL, regs, (unsigned long *)stack, |
| &backtrace_ops, &depth); |
| return; |
| } |
| |
| while (depth-- && head) |
| head = dump_user_backtrace(head); |
| } |