| 1 | /* |
| 2 | * arch/ubicom32/kernel/stacktrace.c |
| 3 | * Ubicom32 architecture stack back trace implementation. |
| 4 | * |
| 5 | * (C) Copyright 2009, Ubicom, Inc. |
| 6 | * |
| 7 | * This file is part of the Ubicom32 Linux Kernel Port. |
| 8 | * |
| 9 | * The Ubicom32 Linux Kernel Port is free software: you can redistribute |
| 10 | * it and/or modify it under the terms of the GNU General Public License |
| 11 | * as published by the Free Software Foundation, either version 2 of the |
| 12 | * License, or (at your option) any later version. |
| 13 | * |
| 14 | * The Ubicom32 Linux Kernel Port is distributed in the hope that it |
| 15 | * will be useful, but WITHOUT ANY WARRANTY; without even the implied |
| 16 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See |
| 17 | * the GNU General Public License for more details. |
| 18 | * |
| 19 | * You should have received a copy of the GNU General Public License |
| 20 | * along with the Ubicom32 Linux Kernel Port. If not, |
| 21 | * see <http://www.gnu.org/licenses/>. |
| 22 | * |
| 23 | * Ubicom32 implementation derived from (with many thanks): |
| 24 | * arch/m68knommu |
| 25 | * arch/blackfin |
| 26 | * arch/parisc |
| 27 | */ |
| 28 | #include <linux/sched.h> |
| 29 | #include <linux/stacktrace.h> |
| 30 | #include <linux/module.h> |
| 31 | #include <asm/stacktrace.h> |
| 32 | #include <asm/thread.h> |
| 33 | #include <asm/ip5000.h> |
| 34 | |
| 35 | /* |
| 36 | * These symbols are filled in by the linker. |
| 37 | */ |
| 38 | extern unsigned long _stext; |
| 39 | extern unsigned long _etext; |
| 40 | |
| 41 | extern unsigned long __ocm_text_run_begin; |
| 42 | extern unsigned long __data_begin; |
| 43 | |
| 44 | /* |
| 45 | * stacktrace_iterate() |
| 46 | * Walk the stack looking for call and calli instructions on an aligned |
| 47 | * boundary. |
| 48 | * |
| 49 | * Trace must point to the top of the current stack frame. |
| 50 | */ |
| 51 | unsigned long stacktrace_iterate(unsigned long **trace, |
| 52 | unsigned long stext, |
| 53 | unsigned long etext, |
| 54 | unsigned long ocm_stext, |
| 55 | unsigned long ocm_etext, |
| 56 | unsigned long sstack, |
| 57 | unsigned long estack) |
| 58 | { |
| 59 | unsigned int thread_trap_en, instruction; |
| 60 | unsigned long address; |
| 61 | unsigned int limit = 0; |
| 62 | unsigned long result = 0; |
| 63 | unsigned long *sp = *trace; |
| 64 | |
| 65 | /* |
| 66 | * Exclude the current thread from being monitored for traps. |
| 67 | */ |
| 68 | asm volatile( |
| 69 | " thread_get_self_mask d15 \n\t" |
| 70 | /* save current trap status */ |
| 71 | " and.4 %0, MT_TRAP_EN, d15 \n\t" |
| 72 | " not.4 d15, d15 \n\t" |
| 73 | /* disable trap */ |
| 74 | " and.4 MT_TRAP_EN, MT_TRAP_EN, d15 \n\t" |
| 75 | " pipe_flush 0 \n\t" |
| 76 | : "=r" (thread_trap_en) |
| 77 | : |
| 78 | : "d15", "cc" |
| 79 | ); |
| 80 | |
| 81 | while (limit++ < 256) { |
| 82 | /* |
| 83 | * See if we have a valid stack. |
| 84 | */ |
| 85 | if (!between((unsigned long)sp, sstack, estack)) { |
| 86 | #ifdef TRAP_DEBUG_STACK_TRACE |
| 87 | printk(KERN_EMERG "stack address is out of range - " |
| 88 | "sp: %x, sstack: %x, estack: %x\n", |
| 89 | (unsigned int)sp, (unsigned int)sstack, |
| 90 | (unsigned int)estack); |
| 91 | #endif |
| 92 | result = 0; |
| 93 | *trace = 0; |
| 94 | break; |
| 95 | } |
| 96 | |
| 97 | /* |
| 98 | * Get the value off the stack and back up 4 bytes to what |
| 99 | * should be the address of a call or calli. |
| 100 | */ |
| 101 | address = (*sp++) - 4; |
| 102 | |
| 103 | /* |
| 104 | * If the address is not within the text segment, skip this |
| 105 | * value. |
| 106 | */ |
| 107 | if (!between(address, stext, etext) && |
| 108 | !between(address, ocm_stext, ocm_etext)) { |
| 109 | #ifdef TRAP_DEBUG_STACK_TRACE |
| 110 | printk(KERN_EMERG "not a text address - " |
| 111 | "address: %08x, stext: %08x, etext: %08x\n" |
| 112 | "ocm_stext: %08x, ocm_etext: %08x\n", |
| 113 | (unsigned int)address, |
| 114 | (unsigned int)stext, |
| 115 | (unsigned int)etext, |
| 116 | (unsigned int)ocm_stext, |
| 117 | (unsigned int)ocm_etext); |
| 118 | #endif |
| 119 | continue; |
| 120 | |
| 121 | } |
| 122 | |
| 123 | /* |
| 124 | * If the address is not on an aligned boundary it can not be a |
| 125 | * return address. |
| 126 | */ |
| 127 | if (address & 0x3) { |
| 128 | continue; |
| 129 | } |
| 130 | |
| 131 | /* |
| 132 | * Read the probable instruction. |
| 133 | */ |
| 134 | instruction = *(unsigned int *)address; |
| 135 | |
| 136 | /* |
| 137 | * Is this a call instruction? |
| 138 | */ |
| 139 | if ((instruction & 0xF8000000) == (u32_t)(0x1B << 27)) { |
| 140 | #ifdef TRAP_DEBUG_STACK_TRACE |
| 141 | printk(KERN_EMERG "call inst. result: %x, " |
| 142 | "test: %x\n", (unsigned int)address, |
| 143 | (unsigned int)instruction); |
| 144 | #endif |
| 145 | *trace = sp; |
| 146 | result = address; |
| 147 | break; |
| 148 | } |
| 149 | |
| 150 | /* |
| 151 | * Is this a calli instruction? |
| 152 | */ |
| 153 | if ((instruction & 0xF8000000) == (u32_t)(0x1E << 27)) { |
| 154 | #ifdef TRAP_DEBUG_STACK_TRACE |
| 155 | printk(KERN_EMERG "calli inst. result: %x, " |
| 156 | "test: %x\n", (unsigned int)address, |
| 157 | (unsigned int)instruction); |
| 158 | #endif |
| 159 | *trace = sp; |
| 160 | result = address; |
| 161 | break; |
| 162 | } |
| 163 | } |
| 164 | |
| 165 | /* |
| 166 | * Restore the current thread to be monitored for traps. |
| 167 | */ |
| 168 | if (thread_trap_en) { |
| 169 | asm volatile( |
| 170 | " thread_get_self_mask d15 \n\t" |
| 171 | " or.4 MT_TRAP_EN, MT_TRAP_EN, d15 \n\t" |
| 172 | : |
| 173 | : |
| 174 | : "d15", "cc" |
| 175 | ); |
| 176 | } |
| 177 | return result; |
| 178 | } |
| 179 | |
| 180 | #ifdef CONFIG_STACKTRACE |
| 181 | /* |
| 182 | * stacktrace_save_entries() |
| 183 | * Save stack back trace information into the provided trace structure. |
| 184 | */ |
| 185 | void stacktrace_save_entries(struct task_struct *tsk, |
| 186 | struct stack_trace *trace, |
| 187 | unsigned long sp) |
| 188 | { |
| 189 | unsigned long code_start = (unsigned long)&_stext; |
| 190 | unsigned long code_end = (unsigned long)&_etext; |
| 191 | unsigned long ocm_code_start = (unsigned long)&__ocm_text_run_begin; |
| 192 | unsigned long ocm_code_end = (unsigned long)&__data_begin; |
| 193 | unsigned long stack_end = (unsigned long)(tsk->stack + THREAD_SIZE - 8); |
| 194 | unsigned long stack = (unsigned long)sp; |
| 195 | unsigned int idx = 0; |
| 196 | unsigned long *handle; |
| 197 | int skip = trace->skip; |
| 198 | |
| 199 | handle = (unsigned long *)stack; |
| 200 | while (idx < trace->max_entries) { |
| 201 | if (skip) { |
| 202 | skip--; |
| 203 | continue; |
| 204 | } |
| 205 | trace->entries[idx] = stacktrace_iterate(&handle, |
| 206 | code_start, code_end, |
| 207 | ocm_code_start, ocm_code_end, |
| 208 | (unsigned long)stack, stack_end); |
| 209 | if (trace->entries[idx] == 0) { |
| 210 | break; |
| 211 | } |
| 212 | idx++; |
| 213 | } |
| 214 | } |
| 215 | |
| 216 | /* |
| 217 | * save_stack_trace() |
| 218 | * Save the specified amount of the kernel stack trace information |
| 219 | * for the current task. |
| 220 | */ |
| 221 | void save_stack_trace(struct stack_trace *trace) |
| 222 | { |
| 223 | unsigned long sp = 0; |
| 224 | asm volatile ( |
| 225 | " move.4 %0, SP \n\t" |
| 226 | : "=r" (sp) |
| 227 | ); |
| 228 | stacktrace_save_entries(current, trace, sp); |
| 229 | } |
| 230 | EXPORT_SYMBOL_GPL(save_stack_trace); |
| 231 | |
| 232 | /* |
| 233 | * save_stack_trace_tsk() |
| 234 | * Save the specified amount of the kernel stack trace information |
| 235 | * for the specified task. |
| 236 | * |
| 237 | * Note: We assume the specified task is not currently running. |
| 238 | */ |
| 239 | void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) |
| 240 | { |
| 241 | stacktrace_save_entries(tsk, trace, tsk->thread.sp); |
| 242 | } |
| 243 | EXPORT_SYMBOL_GPL(save_stack_trace_tsk); |
| 244 | #endif /* CONFIG_STACKTRACE */ |
| 245 | |
