linux/arch/x86/um/ptrace_64.c
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   1/*
   2 * Copyright 2003 PathScale, Inc.
   3 * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   4 *
   5 * Licensed under the GPL
   6 */
   7
   8#include <linux/mm.h>
   9#include <linux/sched.h>
  10#include <linux/errno.h>
  11#define __FRAME_OFFSETS
  12#include <asm/ptrace.h>
  13#include <linux/uaccess.h>
  14#include <asm/ptrace-abi.h>
  15
  16/*
  17 * determines which flags the user has access to.
  18 * 1 = access 0 = no access
  19 */
  20#define FLAG_MASK 0x44dd5UL
  21
  22static const int reg_offsets[] =
  23{
  24        [R8 >> 3] = HOST_R8,
  25        [R9 >> 3] = HOST_R9,
  26        [R10 >> 3] = HOST_R10,
  27        [R11 >> 3] = HOST_R11,
  28        [R12 >> 3] = HOST_R12,
  29        [R13 >> 3] = HOST_R13,
  30        [R14 >> 3] = HOST_R14,
  31        [R15 >> 3] = HOST_R15,
  32        [RIP >> 3] = HOST_IP,
  33        [RSP >> 3] = HOST_SP,
  34        [RAX >> 3] = HOST_AX,
  35        [RBX >> 3] = HOST_BX,
  36        [RCX >> 3] = HOST_CX,
  37        [RDX >> 3] = HOST_DX,
  38        [RSI >> 3] = HOST_SI,
  39        [RDI >> 3] = HOST_DI,
  40        [RBP >> 3] = HOST_BP,
  41        [CS >> 3] = HOST_CS,
  42        [SS >> 3] = HOST_SS,
  43        [FS_BASE >> 3] = HOST_FS_BASE,
  44        [GS_BASE >> 3] = HOST_GS_BASE,
  45        [DS >> 3] = HOST_DS,
  46        [ES >> 3] = HOST_ES,
  47        [FS >> 3] = HOST_FS,
  48        [GS >> 3] = HOST_GS,
  49        [EFLAGS >> 3] = HOST_EFLAGS,
  50        [ORIG_RAX >> 3] = HOST_ORIG_AX,
  51};
  52
  53int putreg(struct task_struct *child, int regno, unsigned long value)
  54{
  55#ifdef TIF_IA32
  56        /*
  57         * Some code in the 64bit emulation may not be 64bit clean.
  58         * Don't take any chances.
  59         */
  60        if (test_tsk_thread_flag(child, TIF_IA32))
  61                value &= 0xffffffff;
  62#endif
  63        switch (regno) {
  64        case R8:
  65        case R9:
  66        case R10:
  67        case R11:
  68        case R12:
  69        case R13:
  70        case R14:
  71        case R15:
  72        case RIP:
  73        case RSP:
  74        case RAX:
  75        case RBX:
  76        case RCX:
  77        case RDX:
  78        case RSI:
  79        case RDI:
  80        case RBP:
  81                break;
  82
  83        case ORIG_RAX:
  84                /* Update the syscall number. */
  85                UPT_SYSCALL_NR(&child->thread.regs.regs) = value;
  86                break;
  87
  88        case FS:
  89        case GS:
  90        case DS:
  91        case ES:
  92        case SS:
  93        case CS:
  94                if (value && (value & 3) != 3)
  95                        return -EIO;
  96                value &= 0xffff;
  97                break;
  98
  99        case FS_BASE:
 100        case GS_BASE:
 101                if (!((value >> 48) == 0 || (value >> 48) == 0xffff))
 102                        return -EIO;
 103                break;
 104
 105        case EFLAGS:
 106                value &= FLAG_MASK;
 107                child->thread.regs.regs.gp[HOST_EFLAGS] |= value;
 108                return 0;
 109
 110        default:
 111                panic("Bad register in putreg(): %d\n", regno);
 112        }
 113
 114        child->thread.regs.regs.gp[reg_offsets[regno >> 3]] = value;
 115        return 0;
 116}
 117
 118int poke_user(struct task_struct *child, long addr, long data)
 119{
 120        if ((addr & 3) || addr < 0)
 121                return -EIO;
 122
 123        if (addr < MAX_REG_OFFSET)
 124                return putreg(child, addr, data);
 125        else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
 126                (addr <= offsetof(struct user, u_debugreg[7]))) {
 127                addr -= offsetof(struct user, u_debugreg[0]);
 128                addr = addr >> 3;
 129                if ((addr == 4) || (addr == 5))
 130                        return -EIO;
 131                child->thread.arch.debugregs[addr] = data;
 132                return 0;
 133        }
 134        return -EIO;
 135}
 136
 137unsigned long getreg(struct task_struct *child, int regno)
 138{
 139        unsigned long mask = ~0UL;
 140#ifdef TIF_IA32
 141        if (test_tsk_thread_flag(child, TIF_IA32))
 142                mask = 0xffffffff;
 143#endif
 144        switch (regno) {
 145        case R8:
 146        case R9:
 147        case R10:
 148        case R11:
 149        case R12:
 150        case R13:
 151        case R14:
 152        case R15:
 153        case RIP:
 154        case RSP:
 155        case RAX:
 156        case RBX:
 157        case RCX:
 158        case RDX:
 159        case RSI:
 160        case RDI:
 161        case RBP:
 162        case ORIG_RAX:
 163        case EFLAGS:
 164        case FS_BASE:
 165        case GS_BASE:
 166                break;
 167        case FS:
 168        case GS:
 169        case DS:
 170        case ES:
 171        case SS:
 172        case CS:
 173                mask = 0xffff;
 174                break;
 175        default:
 176                panic("Bad register in getreg: %d\n", regno);
 177        }
 178        return mask & child->thread.regs.regs.gp[reg_offsets[regno >> 3]];
 179}
 180
 181int peek_user(struct task_struct *child, long addr, long data)
 182{
 183        /* read the word at location addr in the USER area. */
 184        unsigned long tmp;
 185
 186        if ((addr & 3) || addr < 0)
 187                return -EIO;
 188
 189        tmp = 0;  /* Default return condition */
 190        if (addr < MAX_REG_OFFSET)
 191                tmp = getreg(child, addr);
 192        else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
 193                (addr <= offsetof(struct user, u_debugreg[7]))) {
 194                addr -= offsetof(struct user, u_debugreg[0]);
 195                addr = addr >> 2;
 196                tmp = child->thread.arch.debugregs[addr];
 197        }
 198        return put_user(tmp, (unsigned long *) data);
 199}
 200
 201/* XXX Mostly copied from sys-i386 */
 202int is_syscall(unsigned long addr)
 203{
 204        unsigned short instr;
 205        int n;
 206
 207        n = copy_from_user(&instr, (void __user *) addr, sizeof(instr));
 208        if (n) {
 209                /*
 210                 * access_process_vm() grants access to vsyscall and stub,
 211                 * while copy_from_user doesn't. Maybe access_process_vm is
 212                 * slow, but that doesn't matter, since it will be called only
 213                 * in case of singlestepping, if copy_from_user failed.
 214                 */
 215                n = access_process_vm(current, addr, &instr, sizeof(instr),
 216                                FOLL_FORCE);
 217                if (n != sizeof(instr)) {
 218                        printk("is_syscall : failed to read instruction from "
 219                               "0x%lx\n", addr);
 220                        return 1;
 221                }
 222        }
 223        /* sysenter */
 224        return instr == 0x050f;
 225}
 226
 227static int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 228{
 229        int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
 230        struct user_i387_struct fpregs;
 231
 232        err = save_i387_registers(userspace_pid[cpu],
 233                                  (unsigned long *) &fpregs);
 234        if (err)
 235                return err;
 236
 237        n = copy_to_user(buf, &fpregs, sizeof(fpregs));
 238        if (n > 0)
 239                return -EFAULT;
 240
 241        return n;
 242}
 243
 244static int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 245{
 246        int n, cpu = ((struct thread_info *) child->stack)->cpu;
 247        struct user_i387_struct fpregs;
 248
 249        n = copy_from_user(&fpregs, buf, sizeof(fpregs));
 250        if (n > 0)
 251                return -EFAULT;
 252
 253        return restore_i387_registers(userspace_pid[cpu],
 254                                      (unsigned long *) &fpregs);
 255}
 256
 257long subarch_ptrace(struct task_struct *child, long request,
 258                    unsigned long addr, unsigned long data)
 259{
 260        int ret = -EIO;
 261        void __user *datap = (void __user *) data;
 262
 263        switch (request) {
 264        case PTRACE_GETFPREGS: /* Get the child FPU state. */
 265                ret = get_fpregs(datap, child);
 266                break;
 267        case PTRACE_SETFPREGS: /* Set the child FPU state. */
 268                ret = set_fpregs(datap, child);
 269                break;
 270        case PTRACE_ARCH_PRCTL:
 271                /* XXX Calls ptrace on the host - needs some SMP thinking */
 272                ret = arch_prctl(child, data, (void __user *) addr);
 273                break;
 274        }
 275
 276        return ret;
 277}
 278