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Commit 52998578 authored by Chris Dearman's avatar Chris Dearman
Browse files

Dwarf backtrace for MIPS 

The Dwarf parsing code was copied from backtrace-x86.c
and modified for MIPS

Change-Id: I62c698fbbea28be39320a921dd778269dc478528
parent bcf1454c

libcorkscrew/arch-mips/backtrace-mips.c

+822 −83

File changed.

Preview size limit exceeded, changes collapsed.

libcorkscrew/arch-mips/dwarf.h

0 → 100644
+187 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2013 The Android Open Source Project

 *

 * 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.

 */



/*

 * Dwarf2 data encoding flags.

 */



#define DW_EH_PE_absptr         0x00

#define DW_EH_PE_omit           0xff

#define DW_EH_PE_uleb128        0x01

#define DW_EH_PE_udata2         0x02

#define DW_EH_PE_udata4         0x03

#define DW_EH_PE_udata8         0x04

#define DW_EH_PE_sleb128        0x09

#define DW_EH_PE_sdata2         0x0A

#define DW_EH_PE_sdata4         0x0B

#define DW_EH_PE_sdata8         0x0C

#define DW_EH_PE_signed         0x08

#define DW_EH_PE_pcrel          0x10

#define DW_EH_PE_textrel        0x20

#define DW_EH_PE_datarel        0x30

#define DW_EH_PE_funcrel        0x40

#define DW_EH_PE_aligned        0x50

#define DW_EH_PE_indirect       0x80



/*

 * Dwarf2 call frame instructions.

 */



typedef enum {

    DW_CFA_advance_loc = 0x40,

    DW_CFA_offset = 0x80,

    DW_CFA_restore = 0xc0,

    DW_CFA_nop = 0x00,

    DW_CFA_set_loc = 0x01,

    DW_CFA_advance_loc1 = 0x02,

    DW_CFA_advance_loc2 = 0x03,

    DW_CFA_advance_loc4 = 0x04,

    DW_CFA_offset_extended = 0x05,

    DW_CFA_restore_extended = 0x06,

    DW_CFA_undefined = 0x07,

    DW_CFA_same_value = 0x08,

    DW_CFA_register = 0x09,

    DW_CFA_remember_state = 0x0a,

    DW_CFA_restore_state = 0x0b,

    DW_CFA_def_cfa = 0x0c,

    DW_CFA_def_cfa_register = 0x0d,

    DW_CFA_def_cfa_offset = 0x0e

} dwarf_CFA;



/*

 * eh_frame_hdr information.

*/



typedef struct {

      uint8_t version;

      uint8_t eh_frame_ptr_enc;

      uint8_t fde_count_enc;

      uint8_t fde_table_enc;

      uintptr_t eh_frame_ptr;

      uint32_t fde_count;

} eh_frame_hdr_info_t;



/*

 * CIE information.

*/



typedef struct {

      uint8_t version;

      uint32_t code_align;

      uint32_t data_align;

      uint32_t reg;

      uint32_t aug_z;

      uint8_t aug_L;

      uint8_t aug_R;

      uint8_t aug_S;

      uint32_t aug_P;

} cie_info_t;



/*

 * FDE information.

*/



typedef struct {

      uint32_t start;

      uint32_t length; // number of instructions covered by FDE

      uint32_t aug_z;

      uint32_t aug_L;

} fde_info_t;



/*

 * Dwarf state.

*/



/* Stack of states: required for DW_CFA_remember_state/DW_CFA_restore_state

   30 should be enough */

#define DWARF_STATES_STACK 30



typedef struct {

    char rule;         // rule: o - offset(value); r - register(value)

    uint32_t value;    // value

} reg_rule_t;



/* Dwarf preserved number of registers for mips */

typedef enum

  {

    UNW_MIPS_R0,

    UNW_MIPS_R1,

    UNW_MIPS_R2,

    UNW_MIPS_R3,

    UNW_MIPS_R4,

    UNW_MIPS_R5,

    UNW_MIPS_R6,

    UNW_MIPS_R7,

    UNW_MIPS_R8,

    UNW_MIPS_R9,

    UNW_MIPS_R10,

    UNW_MIPS_R11,

    UNW_MIPS_R12,

    UNW_MIPS_R13,

    UNW_MIPS_R14,

    UNW_MIPS_R15,

    UNW_MIPS_R16,

    UNW_MIPS_R17,

    UNW_MIPS_R18,

    UNW_MIPS_R19,

    UNW_MIPS_R20,

    UNW_MIPS_R21,

    UNW_MIPS_R22,

    UNW_MIPS_R23,

    UNW_MIPS_R24,

    UNW_MIPS_R25,

    UNW_MIPS_R26,

    UNW_MIPS_R27,

    UNW_MIPS_R28,

    UNW_MIPS_R29,

    UNW_MIPS_R30,

    UNW_MIPS_R31,



    UNW_MIPS_PC = 34,



    /* FIXME: Other registers!  */



    /* For MIPS, the CFA is the value of SP (r29) at the call site in the

       previous frame.  */

    UNW_MIPS_CFA,



    UNW_TDEP_LASTREG,



    UNW_TDEP_LAST_REG = UNW_MIPS_R31,



    UNW_TDEP_IP = UNW_MIPS_R31,

    UNW_TDEP_SP = UNW_MIPS_R29,

    UNW_TDEP_EH = UNW_MIPS_R0   /* FIXME.  */



  }

mips_regnum_t;



#define DWARF_REGISTERS UNW_TDEP_LASTREG



typedef struct {

    uintptr_t loc;     // location (ip)

    uint8_t cfa_reg;   // index of register where CFA location stored

    intptr_t cfa_off;  // offset

    reg_rule_t regs[DWARF_REGISTERS]; // dwarf preserved registers for mips

} dwarf_state_t;



/* DWARF registers we are caring about. */





#define DWARF_SP      UNW_MIPS_R29

#define DWARF_RA      UNW_MIPS_R31

#define DWARF_PC      UNW_MIPS_PC

#define DWARF_FP      UNW_MIPS_CFA /* FIXME is this correct? */

libcorkscrew/arch-mips/ptrace-mips.c

+50 −1
Original line number Diff line number Diff line
@@ -19,10 +19,59 @@ 


#include "../ptrace-arch.h"



#include <stddef.h>

#include <elf.h>

#include <cutils/log.h>



static void load_eh_frame_hdr(pid_t pid, map_info_t* mi, uintptr_t *eh_frame_hdr) {

    uint32_t elf_phoff;

    uint32_t elf_phentsize_ehsize;

    uint32_t elf_shentsize_phnum;





    try_get_word_ptrace(pid, mi->start + offsetof(Elf32_Ehdr, e_phoff), &elf_phoff);

    ALOGV("reading 0x%08x elf_phoff:%x",  mi->start + offsetof(Elf32_Ehdr, e_phoff), elf_phoff);

    try_get_word_ptrace(pid, mi->start + offsetof(Elf32_Ehdr, e_ehsize), &elf_phentsize_ehsize);

    ALOGV("reading 0x%08x elf_phentsize_ehsize:%x", mi->start + offsetof(Elf32_Ehdr, e_ehsize), elf_phentsize_ehsize);

    try_get_word_ptrace(pid, mi->start + offsetof(Elf32_Ehdr, e_phnum), &elf_shentsize_phnum);

    ALOGV("reading 0x%08x elf_shentsize_phnum:%x", mi->start + offsetof(Elf32_Ehdr, e_phnum), elf_shentsize_phnum);







    if (try_get_word_ptrace(pid, mi->start + offsetof(Elf32_Ehdr, e_phoff), &elf_phoff)

            && try_get_word_ptrace(pid, mi->start + offsetof(Elf32_Ehdr, e_ehsize),

                    &elf_phentsize_ehsize)

            && try_get_word_ptrace(pid, mi->start + offsetof(Elf32_Ehdr, e_phnum),

                    &elf_shentsize_phnum)) {

        uint32_t elf_phentsize = elf_phentsize_ehsize >> 16;

        uint32_t elf_phnum = elf_shentsize_phnum & 0xffff;

        for (uint32_t i = 0; i < elf_phnum; i++) {

            uintptr_t elf_phdr = mi->start + elf_phoff + i * elf_phentsize;

            uint32_t elf_phdr_type;

            if (!try_get_word_ptrace(pid, elf_phdr + offsetof(Elf32_Phdr, p_type), &elf_phdr_type)) {

                break;

            }

            if (elf_phdr_type == PT_GNU_EH_FRAME) {

                uint32_t elf_phdr_offset;

                if (!try_get_word_ptrace(pid, elf_phdr + offsetof(Elf32_Phdr, p_offset),

                        &elf_phdr_offset)) {

                    break;

                }

                *eh_frame_hdr = mi->start + elf_phdr_offset;

                ALOGV("Parsed .eh_frame_hdr info for %s: start=0x%08x", mi->name, *eh_frame_hdr);

                return;

            }

        }

    }

    *eh_frame_hdr = 0;

}



void load_ptrace_map_info_data_arch(pid_t pid, map_info_t* mi, map_info_data_t* data) {

    ALOGV("load_ptrace_map_info_data_arch");

    load_eh_frame_hdr(pid, mi, &data->eh_frame_hdr);

}



void free_ptrace_map_info_data_arch(map_info_t* mi, map_info_data_t* data) {

void free_ptrace_map_info_data_arch(map_info_t* mi __attribute__((unused)),

                                    map_info_data_t* data __attribute__((unused))) {

    ALOGV("free_ptrace_map_info_data_arch");

}

libcorkscrew/ptrace-arch.h

+2 −0
Original line number Diff line number Diff line
@@ -33,6 +33,8 @@ typedef struct { 
#ifdef __arm__

    uintptr_t exidx_start;

    size_t exidx_size;

#elif __mips__

    uintptr_t eh_frame_hdr;

#elif __i386__

    uintptr_t eh_frame_hdr;

#endif