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Diffstat (limited to 'src/vppinfra/backtrace.c')
| -rw-r--r-- | src/vppinfra/backtrace.c | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/src/vppinfra/backtrace.c b/src/vppinfra/backtrace.c new file mode 100644 index 00000000..bbfb792c --- /dev/null +++ b/src/vppinfra/backtrace.c @@ -0,0 +1,267 @@ +/* + * Copyright (c) 2015 Cisco and/or its affiliates. + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at: + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +/* + Copyright (c) 2004 Eliot Dresselhaus + + Permission is hereby granted, free of charge, to any person obtaining + a copy of this software and associated documentation files (the + "Software"), to deal in the Software without restriction, including + without limitation the rights to use, copy, modify, merge, publish, + distribute, sublicense, and/or sell copies of the Software, and to + permit persons to whom the Software is furnished to do so, subject to + the following conditions: + + The above copyright notice and this permission notice shall be + included in all copies or substantial portions of the Software. + + THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE + LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION + OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION + WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. +*/ + +#include <vppinfra/clib.h> +#include <vppinfra/error.h> + +#ifdef __mips__ + +/* Let code below know we've defined _clib_backtrace */ +#define clib_backtrace_defined + +#include <vppinfra/asm_mips.h> + +uword +clib_backtrace (uword * callers, uword max_callers, uword n_frames_to_skip) +{ + u32 *pc; + void *sp; + uword i, saved_pc; + + /* Figure current PC, saved PC and stack pointer. */ + asm volatile (".set push\n" + ".set noat\n" "move %[saved_pc], $31\n" "move %[sp], $29\n" + /* Fetches current PC. */ + "la $at, 1f\n" + "jalr %[pc], $at\n" + "nop\n" + "1:\n" + ".set pop\n":[pc] "=r" (pc), + [saved_pc] "=r" (saved_pc),[sp] "=r" (sp)); + + /* Also skip current frame. */ + n_frames_to_skip += 1; + + for (i = 0; i < max_callers + n_frames_to_skip; i++) + { + mips_insn_opcode_t op; + mips_insn_special_funct_t funct; + i32 insn, rs, rt, rd, immediate, found_saved_pc; + u32 *start_pc; + + /* Parse instructions until we reach prologue for this + stack frame. We'll need to figure out where saved + PC is and where previous stack frame lives. */ + start_pc = pc; + found_saved_pc = 0; + while (1) + { + insn = *--pc; + op = mips_insn_get_op (insn); + funct = mips_insn_get_funct (insn); + rs = mips_insn_get_rs (insn); + rt = mips_insn_get_rt (insn); + rd = mips_insn_get_rd (insn); + immediate = mips_insn_get_immediate (insn); + + switch (op) + { + default: + break; + + case MIPS_OPCODE_sd: + case MIPS_OPCODE_sw: + /* Trace stores of return address. */ + if (rt == MIPS_REG_RA) + { + void *addr = sp + immediate; + + /* If RA is stored somewhere other than in the + stack frame, give up. */ + if (rs != MIPS_REG_SP) + goto backtrace_done; + + ASSERT (immediate % 4 == 0); + if (op == MIPS_OPCODE_sw) + saved_pc = ((u32 *) addr)[0]; + else + saved_pc = ((u64 *) addr)[0]; + found_saved_pc = 1; + } + break; + + case MIPS_OPCODE_addiu: + case MIPS_OPCODE_daddiu: + case MIPS_OPCODE_addi: + case MIPS_OPCODE_daddi: + if (rt == MIPS_REG_SP) + { + if (rs != MIPS_REG_SP) + goto backtrace_done; + + ASSERT (immediate % 4 == 0); + + /* Assume positive offset is part of the epilogue. + E.g. + jr ra + add sp,sp,100 + */ + if (immediate > 0) + continue; + + /* Negative offset means allocate stack space. + This could either be the prologue or could be due to + alloca. */ + sp -= immediate; + + /* This frame will not save RA. */ + if (i == 0) + goto found_prologue; + + /* Assume that addiu sp,sp,-N without store of ra means + that we have not found the prologue yet. */ + if (found_saved_pc) + goto found_prologue; + } + break; + + case MIPS_OPCODE_slti: + case MIPS_OPCODE_sltiu: + case MIPS_OPCODE_andi: + case MIPS_OPCODE_ori: + case MIPS_OPCODE_xori: + case MIPS_OPCODE_lui: + case MIPS_OPCODE_ldl: + case MIPS_OPCODE_ldr: + case MIPS_OPCODE_lb: + case MIPS_OPCODE_lh: + case MIPS_OPCODE_lwl: + case MIPS_OPCODE_lw: + case MIPS_OPCODE_lbu: + case MIPS_OPCODE_lhu: + case MIPS_OPCODE_lwr: + case MIPS_OPCODE_lwu: + case MIPS_OPCODE_ld: + /* Give up when we find anyone setting the stack pointer. */ + if (rt == MIPS_REG_SP) + goto backtrace_done; + break; + + case MIPS_OPCODE_SPECIAL: + if (rd == MIPS_REG_SP) + switch (funct) + { + default: + /* Give up when we find anyone setting the stack pointer. */ + goto backtrace_done; + + case MIPS_SPECIAL_FUNCT_break: + case MIPS_SPECIAL_FUNCT_jr: + case MIPS_SPECIAL_FUNCT_sync: + case MIPS_SPECIAL_FUNCT_syscall: + case MIPS_SPECIAL_FUNCT_tge: + case MIPS_SPECIAL_FUNCT_tgeu: + case MIPS_SPECIAL_FUNCT_tlt: + case MIPS_SPECIAL_FUNCT_tltu: + case MIPS_SPECIAL_FUNCT_teq: + case MIPS_SPECIAL_FUNCT_tne: + /* These instructions can validly have rd == MIPS_REG_SP */ + break; + } + break; + } + } + + found_prologue: + /* Check sanity of saved pc. */ + if (saved_pc & 3) + goto backtrace_done; + if (saved_pc == 0) + goto backtrace_done; + + if (i >= n_frames_to_skip) + callers[i - n_frames_to_skip] = saved_pc; + pc = uword_to_pointer (saved_pc, u32 *); + } + +backtrace_done: + if (i < n_frames_to_skip) + return 0; + else + return i - n_frames_to_skip; +} +#endif /* __mips__ */ + +#ifndef clib_backtrace_defined +#define clib_backtrace_defined + +typedef struct clib_generic_stack_frame_t +{ + struct clib_generic_stack_frame_t *prev; + void *return_address; +} clib_generic_stack_frame_t; + +/* This will only work if we have a frame pointer. + Without a frame pointer we have to parse the machine code to + parse the stack frames. */ +uword +clib_backtrace (uword * callers, uword max_callers, uword n_frames_to_skip) +{ + clib_generic_stack_frame_t *f; + uword i; + + f = __builtin_frame_address (0); + + /* Also skip current frame. */ + n_frames_to_skip += 1; + + for (i = 0; i < max_callers + n_frames_to_skip; i++) + { + f = f->prev; + if (!f) + goto backtrace_done; + if (clib_abs ((void *) f - (void *) f->prev) > (64 * 1024)) + goto backtrace_done; + if (i >= n_frames_to_skip) + callers[i - n_frames_to_skip] = pointer_to_uword (f->return_address); + } + +backtrace_done: + if (i < n_frames_to_skip) + return 0; + else + return i - n_frames_to_skip; +} +#endif /* clib_backtrace_defined */ + +/* + * fd.io coding-style-patch-verification: ON + * + * Local Variables: + * eval: (c-set-style "gnu") + * End: + */ |