| Brian Rogan | 6c6bd75 | 2006-03-27 11:57:01 +1100 | [diff] [blame^] | 1 | /** |
| 2 | * Copyright (C) 2005 Brian Rogan <bcr6@cornell.edu>, IBM |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU General Public License |
| 6 | * as published by the Free Software Foundation; either version |
| 7 | * 2 of the License, or (at your option) any later version. |
| 8 | **/ |
| 9 | |
| 10 | #include <linux/oprofile.h> |
| 11 | #include <linux/sched.h> |
| 12 | #include <asm/processor.h> |
| 13 | #include <asm/uaccess.h> |
| 14 | |
| 15 | #define STACK_SP(STACK) *(STACK) |
| 16 | |
| 17 | #define STACK_LR64(STACK) *((unsigned long *)(STACK) + 2) |
| 18 | #define STACK_LR32(STACK) *((unsigned int *)(STACK) + 1) |
| 19 | |
| 20 | #ifdef CONFIG_PPC64 |
| 21 | #define STACK_LR(STACK) STACK_LR64(STACK) |
| 22 | #else |
| 23 | #define STACK_LR(STACK) STACK_LR32(STACK) |
| 24 | #endif |
| 25 | |
| 26 | static unsigned int user_getsp32(unsigned int sp, int is_first) |
| 27 | { |
| 28 | unsigned int stack_frame[2]; |
| 29 | |
| 30 | if (!access_ok(VERIFY_READ, sp, sizeof(stack_frame))) |
| 31 | return 0; |
| 32 | |
| 33 | /* |
| 34 | * The most likely reason for this is that we returned -EFAULT, |
| 35 | * which means that we've done all that we can do from |
| 36 | * interrupt context. |
| 37 | */ |
| 38 | if (__copy_from_user_inatomic(stack_frame, (void *)(long)sp, |
| 39 | sizeof(stack_frame))) |
| 40 | return 0; |
| 41 | |
| 42 | if (!is_first) |
| 43 | oprofile_add_trace(STACK_LR32(stack_frame)); |
| 44 | |
| 45 | /* |
| 46 | * We do not enforce increasing stack addresses here because |
| 47 | * we may transition to a different stack, eg a signal handler. |
| 48 | */ |
| 49 | return STACK_SP(stack_frame); |
| 50 | } |
| 51 | |
| 52 | #ifdef CONFIG_PPC64 |
| 53 | static unsigned long user_getsp64(unsigned long sp, int is_first) |
| 54 | { |
| 55 | unsigned long stack_frame[3]; |
| 56 | |
| 57 | if (!access_ok(VERIFY_READ, sp, sizeof(stack_frame))) |
| 58 | return 0; |
| 59 | |
| 60 | if (__copy_from_user_inatomic(stack_frame, (void *)sp, |
| 61 | sizeof(stack_frame))) |
| 62 | return 0; |
| 63 | |
| 64 | if (!is_first) |
| 65 | oprofile_add_trace(STACK_LR64(stack_frame)); |
| 66 | |
| 67 | return STACK_SP(stack_frame); |
| 68 | } |
| 69 | #endif |
| 70 | |
| 71 | static unsigned long kernel_getsp(unsigned long sp, int is_first) |
| 72 | { |
| 73 | unsigned long *stack_frame = (unsigned long *)sp; |
| 74 | |
| 75 | if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD)) |
| 76 | return 0; |
| 77 | |
| 78 | if (!is_first) |
| 79 | oprofile_add_trace(STACK_LR(stack_frame)); |
| 80 | |
| 81 | /* |
| 82 | * We do not enforce increasing stack addresses here because |
| 83 | * we might be transitioning from an interrupt stack to a kernel |
| 84 | * stack. validate_sp() is designed to understand this, so just |
| 85 | * use it. |
| 86 | */ |
| 87 | return STACK_SP(stack_frame); |
| 88 | } |
| 89 | |
| 90 | void op_powerpc_backtrace(struct pt_regs * const regs, unsigned int depth) |
| 91 | { |
| 92 | unsigned long sp = regs->gpr[1]; |
| 93 | int first_frame = 1; |
| 94 | |
| 95 | /* We ditch the top stackframe so need to loop through an extra time */ |
| 96 | depth += 1; |
| 97 | |
| 98 | if (!user_mode(regs)) { |
| 99 | while (depth--) { |
| 100 | sp = kernel_getsp(sp, first_frame); |
| 101 | if (!sp) |
| 102 | break; |
| 103 | first_frame = 0; |
| 104 | } |
| 105 | } else { |
| 106 | #ifdef CONFIG_PPC64 |
| 107 | if (!test_thread_flag(TIF_32BIT)) { |
| 108 | while (depth--) { |
| 109 | sp = user_getsp64(sp, first_frame); |
| 110 | if (!sp) |
| 111 | break; |
| 112 | first_frame = 0; |
| 113 | } |
| 114 | |
| 115 | return; |
| 116 | } |
| 117 | #endif |
| 118 | |
| 119 | while (depth--) { |
| 120 | sp = user_getsp32(sp, first_frame); |
| 121 | if (!sp) |
| 122 | break; |
| 123 | first_frame = 0; |
| 124 | } |
| 125 | } |
| 126 | } |