1 /* 2 * This file is part of ltrace. 3 * Copyright (C) 2013 Petr Machata, Red Hat Inc. 4 * Copyright (C) 1998,2002,2004,2008,2009 Juan Cespedes 5 * Copyright (C) 2009 Juan Cespedes 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License as 9 * published by the Free Software Foundation; either version 2 of the 10 * License, or (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, but 13 * WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 20 * 02110-1301 USA 21 */ 22 23 #include "config.h" 24 25 #include <sys/types.h> 26 #include <sys/ptrace.h> 27 #include <asm/ptrace.h> 28 #include <errno.h> 29 30 #include "proc.h" 31 #include "common.h" 32 #include "regs.h" 33 34 #if (!defined(PTRACE_PEEKUSER) && defined(PTRACE_PEEKUSR)) 35 # define PTRACE_PEEKUSER PTRACE_PEEKUSR 36 #endif 37 38 #if (!defined(PTRACE_POKEUSER) && defined(PTRACE_POKEUSR)) 39 # define PTRACE_POKEUSER PTRACE_POKEUSR 40 #endif 41 42 int 43 arm_get_register(struct process *proc, enum arm_register reg, uint32_t *lp) 44 { 45 errno = 0; 46 long l = ptrace(PTRACE_PEEKUSER, proc->pid, (void *)(reg * 4L), 0); 47 if (l == -1 && errno != 0) 48 return -1; 49 *lp = (uint32_t)l; 50 return 0; 51 } 52 53 int 54 arm_set_register(struct process *proc, enum arm_register reg, uint32_t lp) 55 { 56 return ptrace(PTRACE_PEEKUSER, proc->pid, 57 (void *)(reg * 4L), (void *)lp); 58 } 59 60 int 61 arm_get_register_offpc(struct process *proc, enum arm_register reg, 62 uint32_t *lp) 63 { 64 if (arm_get_register(proc, reg, lp) < 0) 65 return -1; 66 if (reg == ARM_REG_PC) 67 *lp += 8; 68 return 0; 69 } 70 71 int 72 arm_get_shifted_register(struct process *proc, uint32_t inst, int carry, 73 arch_addr_t pc_val, uint32_t *lp) 74 { 75 enum arm_register rm = BITS(inst, 0, 3); 76 unsigned long shifttype = BITS(inst, 5, 6); 77 78 uint32_t shift; 79 if (BIT(inst, 4)) { 80 if (arm_get_register_offpc(proc, BITS(inst, 8, 11), &shift) < 0) 81 return -1; 82 shift &= 0xff; 83 } else { 84 shift = BITS(inst, 7, 11); 85 } 86 87 uint32_t res; 88 if (rm == ARM_REG_PC) 89 /* xxx double cast */ 90 res = (uintptr_t)pc_val + (BIT(inst, 4) ? 12 : 8); 91 else if (arm_get_register(proc, rm, &res) < 0) 92 return -1; 93 94 switch (shifttype) { 95 case 0: /* LSL */ 96 res = shift >= 32 ? 0 : res << shift; 97 break; 98 99 case 1: /* LSR */ 100 res = shift >= 32 ? 0 : res >> shift; 101 break; 102 103 case 2: /* ASR */ 104 if (shift >= 32) 105 shift = 31; 106 res = ((res & 0x80000000L) 107 ? ~((~res) >> shift) : res >> shift); 108 break; 109 110 case 3: /* ROR/RRX */ 111 shift &= 31; 112 if (shift == 0) 113 res = (res >> 1) | (carry ? 0x80000000L : 0); 114 else 115 res = (res >> shift) | (res << (32 - shift)); 116 break; 117 } 118 119 *lp = res & 0xffffffff; 120 return 0; 121 } 122 123 static arch_addr_t 124 get_register_nocheck(struct process *proc, enum arm_register r) 125 { 126 uint32_t reg; 127 if (arm_get_register(proc, r, ®) < 0) 128 /* XXX double cast. */ 129 return (arch_addr_t)-1; 130 /* XXX double cast. */ 131 return (arch_addr_t)(uintptr_t)reg; 132 } 133 134 arch_addr_t 135 get_instruction_pointer(struct process *proc) 136 { 137 return get_register_nocheck(proc, ARM_REG_PC); 138 } 139 140 void 141 set_instruction_pointer(struct process *proc, arch_addr_t addr) 142 { 143 /* XXX double cast. */ 144 arm_set_register(proc, ARM_REG_PC, (uint32_t)addr); 145 } 146 147 void * 148 get_stack_pointer(struct process *proc) 149 { 150 return get_register_nocheck(proc, ARM_REG_SP); 151 } 152 153 arch_addr_t 154 get_return_addr(struct process *proc, arch_addr_t stack_pointer) 155 { 156 return get_register_nocheck(proc, ARM_REG_LR); 157 } 158
