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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 | /* * arch/sh/kernel/cpu/sh5/unwind.c * * Copyright (C) 2004 Paul Mundt * Copyright (C) 2004 Richard Curnow * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. */ #include <linux/kallsyms.h> #include <linux/kernel.h> #include <linux/types.h> #include <linux/errno.h> #include <asm/page.h> #include <asm/ptrace.h> #include <asm/processor.h> #include <asm/io.h> #include <asm/unwinder.h> #include <asm/stacktrace.h> static u8 regcache[63]; /* * Finding the previous stack frame isn't horribly straightforward as it is * on some other platforms. In the sh64 case, we don't have "linked" stack * frames, so we need to do a bit of work to determine the previous frame, * and in turn, the previous r14/r18 pair. * * There are generally a few cases which determine where we can find out * the r14/r18 values. In the general case, this can be determined by poking * around the prologue of the symbol PC is in (note that we absolutely must * have frame pointer support as well as the kernel symbol table mapped, * otherwise we can't even get this far). * * In other cases, such as the interrupt/exception path, we can poke around * the sp/fp. * * Notably, this entire approach is somewhat error prone, and in the event * that the previous frame cannot be determined, that's all we can do. * Either way, this still leaves us with a more correct backtrace then what * we would be able to come up with by walking the stack (which is garbage * for anything beyond the first frame). * -- PFM. */ static int lookup_prev_stack_frame(unsigned long fp, unsigned long pc, unsigned long *pprev_fp, unsigned long *pprev_pc, struct pt_regs *regs) { const char *sym; char namebuf[128]; unsigned long offset; unsigned long prologue = 0; unsigned long fp_displacement = 0; unsigned long fp_prev = 0; unsigned long offset_r14 = 0, offset_r18 = 0; int i, found_prologue_end = 0; sym = kallsyms_lookup(pc, NULL, &offset, NULL, namebuf); if (!sym) return -EINVAL; prologue = pc - offset; if (!prologue) return -EINVAL; /* Validate fp, to avoid risk of dereferencing a bad pointer later. Assume 128Mb since that's the amount of RAM on a Cayman. Modify when there is an SH-5 board with more. */ if ((fp < (unsigned long) phys_to_virt(__MEMORY_START)) || (fp >= (unsigned long)(phys_to_virt(__MEMORY_START)) + 128*1024*1024) || ((fp & 7) != 0)) { return -EINVAL; } /* * Depth to walk, depth is completely arbitrary. */ for (i = 0; i < 100; i++, prologue += sizeof(unsigned long)) { unsigned long op; u8 major, minor; u8 src, dest, disp; op = *(unsigned long *)prologue; major = (op >> 26) & 0x3f; src = (op >> 20) & 0x3f; minor = (op >> 16) & 0xf; disp = (op >> 10) & 0x3f; dest = (op >> 4) & 0x3f; /* * Stack frame creation happens in a number of ways.. in the * general case when the stack frame is less than 511 bytes, * it's generally created by an addi or addi.l: * * addi/addi.l r15, -FRAME_SIZE, r15 * * in the event that the frame size is bigger than this, it's * typically created using a movi/sub pair as follows: * * movi FRAME_SIZE, rX * sub r15, rX, r15 */ switch (major) { case (0x00 >> 2): switch (minor) { case 0x8: /* add.l */ case 0x9: /* add */ /* Look for r15, r63, r14 */ if (src == 15 && disp == 63 && dest == 14) found_prologue_end = 1; break; case 0xa: /* sub.l */ case 0xb: /* sub */ if (src != 15 || dest != 15) continue; fp_displacement -= regcache[disp]; fp_prev = fp - fp_displacement; break; } break; case (0xa8 >> 2): /* st.l */ if (src != 15) continue; switch (dest) { case 14: if (offset_r14 || fp_displacement == 0) continue; offset_r14 = (u64)(((((s64)op >> 10) & 0x3ff) << 54) >> 54); offset_r14 *= sizeof(unsigned long); offset_r14 += fp_displacement; break; case 18: if (offset_r18 || fp_displacement == 0) continue; offset_r18 = (u64)(((((s64)op >> 10) & 0x3ff) << 54) >> 54); offset_r18 *= sizeof(unsigned long); offset_r18 += fp_displacement; break; } break; case (0xcc >> 2): /* movi */ if (dest >= 63) { printk(KERN_NOTICE "%s: Invalid dest reg %d " "specified in movi handler. Failed " "opcode was 0x%lx: ", __func__, dest, op); continue; } /* Sign extend */ regcache[dest] = ((((s64)(u64)op >> 10) & 0xffff) << 54) >> 54; break; case (0xd0 >> 2): /* addi */ case (0xd4 >> 2): /* addi.l */ /* Look for r15, -FRAME_SIZE, r15 */ if (src != 15 || dest != 15) continue; /* Sign extended frame size.. */ fp_displacement += (u64)(((((s64)op >> 10) & 0x3ff) << 54) >> 54); fp_prev = fp - fp_displacement; break; } if (found_prologue_end && offset_r14 && (offset_r18 || *pprev_pc) && fp_prev) break; } if (offset_r14 == 0 || fp_prev == 0) { if (!offset_r14) pr_debug("Unable to find r14 offset\n"); if (!fp_prev) pr_debug("Unable to find previous fp\n"); return -EINVAL; } /* For innermost leaf function, there might not be a offset_r18 */ if (!*pprev_pc && (offset_r18 == 0)) return -EINVAL; *pprev_fp = *(unsigned long *)(fp_prev + offset_r14); if (offset_r18) *pprev_pc = *(unsigned long *)(fp_prev + offset_r18); *pprev_pc &= ~1; return 0; } /* * Don't put this on the stack since we'll want to call in to * sh64_unwinder_dump() when we're close to underflowing the stack * anyway. */ static struct pt_regs here_regs; extern const char syscall_ret; extern const char ret_from_syscall; extern const char ret_from_exception; extern const char ret_from_irq; static void sh64_unwind_inner(const struct stacktrace_ops *ops, void *data, struct pt_regs *regs); static inline void unwind_nested(const struct stacktrace_ops *ops, void *data, unsigned long pc, unsigned long fp) { if ((fp >= __MEMORY_START) && ((fp & 7) == 0)) sh64_unwind_inner(ops, data, (struct pt_regs *)fp); } static void sh64_unwind_inner(const struct stacktrace_ops *ops, void *data, struct pt_regs *regs) { unsigned long pc, fp; int ofs = 0; int first_pass; pc = regs->pc & ~1; fp = regs->regs[14]; first_pass = 1; for (;;) { int cond; unsigned long next_fp, next_pc; if (pc == ((unsigned long)&syscall_ret & ~1)) { printk("SYSCALL\n"); unwind_nested(ops, data, pc, fp); return; } if (pc == ((unsigned long)&ret_from_syscall & ~1)) { printk("SYSCALL (PREEMPTED)\n"); unwind_nested(ops, data, pc, fp); return; } /* In this case, the PC is discovered by lookup_prev_stack_frame but it has 4 taken off it to look like the 'caller' */ if (pc == ((unsigned long)&ret_from_exception & ~1)) { printk("EXCEPTION\n"); unwind_nested(ops, data, pc, fp); return; } if (pc == ((unsigned long)&ret_from_irq & ~1)) { printk("IRQ\n"); unwind_nested(ops, data, pc, fp); return; } cond = ((pc >= __MEMORY_START) && (fp >= __MEMORY_START) && ((pc & 3) == 0) && ((fp & 7) == 0)); pc -= ofs; ops->address(data, pc, 1); if (first_pass) { /* If the innermost frame is a leaf function, it's * possible that r18 is never saved out to the stack. */ next_pc = regs->regs[18]; } else { next_pc = 0; } if (lookup_prev_stack_frame(fp, pc, &next_fp, &next_pc, regs) == 0) { ofs = sizeof(unsigned long); pc = next_pc & ~1; fp = next_fp; } else { printk("Unable to lookup previous stack frame\n"); break; } first_pass = 0; } printk("\n"); } static void sh64_unwinder_dump(struct task_struct *task, struct pt_regs *regs, unsigned long *sp, const struct stacktrace_ops *ops, void *data) { if (!regs) { /* * Fetch current regs if we have no other saved state to back * trace from. */ regs = &here_regs; __asm__ __volatile__ ("ori r14, 0, %0" : "=r" (regs->regs[14])); __asm__ __volatile__ ("ori r15, 0, %0" : "=r" (regs->regs[15])); __asm__ __volatile__ ("ori r18, 0, %0" : "=r" (regs->regs[18])); __asm__ __volatile__ ("gettr tr0, %0" : "=r" (regs->tregs[0])); __asm__ __volatile__ ("gettr tr1, %0" : "=r" (regs->tregs[1])); __asm__ __volatile__ ("gettr tr2, %0" : "=r" (regs->tregs[2])); __asm__ __volatile__ ("gettr tr3, %0" : "=r" (regs->tregs[3])); __asm__ __volatile__ ("gettr tr4, %0" : "=r" (regs->tregs[4])); __asm__ __volatile__ ("gettr tr5, %0" : "=r" (regs->tregs[5])); __asm__ __volatile__ ("gettr tr6, %0" : "=r" (regs->tregs[6])); __asm__ __volatile__ ("gettr tr7, %0" : "=r" (regs->tregs[7])); __asm__ __volatile__ ( "pta 0f, tr0\n\t" "blink tr0, %0\n\t" "0: nop" : "=r" (regs->pc) ); } sh64_unwind_inner(ops, data, regs); } static struct unwinder sh64_unwinder = { .name = "sh64-unwinder", .dump = sh64_unwinder_dump, .rating = 150, }; static int __init sh64_unwinder_init(void) { return unwinder_register(&sh64_unwinder); } early_initcall(sh64_unwinder_init); |