--- /dev/null
+/*
+ * 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 */
Code Review / vpp.git / blobdiff