| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2000 Anton Blanchard (anton@linuxcare.com) |
| 3 | * |
| 4 | * This file implements mcount(), which is used to collect profiling data. |
| 5 | * This can also be tweaked for kernel stack overflow detection. |
| 6 | */ |
| 7 | |
| 8 | #include <linux/config.h> |
| 9 | #include <linux/linkage.h> |
| 10 | |
| 11 | #include <asm/ptrace.h> |
| 12 | #include <asm/thread_info.h> |
| 13 | |
| 14 | /* |
| 15 | * This is the main variant and is called by C code. GCC's -pg option |
| 16 | * automatically instruments every C function with a call to this. |
| 17 | */ |
| 18 | |
| 19 | #ifdef CONFIG_STACK_DEBUG |
| 20 | |
| 21 | #define OVSTACKSIZE 4096 /* lets hope this is enough */ |
| 22 | |
| 23 | .data |
| 24 | .align 8 |
| 25 | panicstring: |
| 26 | .asciz "Stack overflow\n" |
| 27 | .align 8 |
| 28 | ovstack: |
| 29 | .skip OVSTACKSIZE |
| 30 | #endif |
| 31 | .text |
| 32 | .align 32 |
| 33 | .globl mcount, _mcount |
| 34 | mcount: |
| 35 | _mcount: |
| 36 | #ifdef CONFIG_STACK_DEBUG |
| 37 | /* |
| 38 | * Check whether %sp is dangerously low. |
| 39 | */ |
| 40 | ldub [%g6 + TI_FPDEPTH], %g1 |
| 41 | srl %g1, 1, %g3 |
| 42 | add %g3, 1, %g3 |
| 43 | sllx %g3, 8, %g3 ! each fpregs frame is 256b |
| 44 | add %g3, 192, %g3 |
| 45 | add %g6, %g3, %g3 ! where does task_struct+frame end? |
| 46 | sub %g3, STACK_BIAS, %g3 |
| 47 | cmp %sp, %g3 |
| 48 | bg,pt %xcc, 1f |
| 49 | sethi %hi(panicstring), %g3 |
| 50 | sethi %hi(ovstack), %g7 ! cant move to panic stack fast enough |
| 51 | or %g7, %lo(ovstack), %g7 |
| 52 | add %g7, OVSTACKSIZE, %g7 |
| 53 | sub %g7, STACK_BIAS, %g7 |
| 54 | mov %g7, %sp |
| 55 | call prom_printf |
| 56 | or %g3, %lo(panicstring), %o0 |
| 57 | call prom_halt |
| 58 | nop |
| 59 | #endif |
| 60 | 1: retl |
| 61 | nop |