arch/x86/um/ptrace_64.c

   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
  22 static 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
  53 int putreg(struct task_struct *child, int regno, unsigned long value)
  54 {
  55         switch (regno) {
  56         case R8:
  57         case R9:
  58         case R10:
  59         case R11:
  60         case R12:
  61         case R13:
  62         case R14:
  63         case R15:
  64         case RIP:
  65         case RSP:
  66         case RAX:
  67         case RBX:
  68         case RCX:
  69         case RDX:
  70         case RSI:
  71         case RDI:
  72         case RBP:
  73                 break;
  74
  75         case ORIG_RAX:
  76                 /* Update the syscall number. */
  77                 UPT_SYSCALL_NR(&child->thread.regs.regs) = value;
  78                 break;
  79
  80         case FS:
  81         case GS:
  82         case DS:
  83         case ES:
  84         case SS:
  85         case CS:
  86                 if (value && (value & 3) != 3)
  87                         return -EIO;
  88                 value &= 0xffff;
  89                 break;
  90
  91         case FS_BASE:
  92         case GS_BASE:
  93                 if (!((value >> 48) == 0 || (value >> 48) == 0xffff))
  94                         return -EIO;
  95                 break;
  96
  97         case EFLAGS:
  98                 value &= FLAG_MASK;
  99                 child->thread.regs.regs.gp[HOST_EFLAGS] |= value;
 100                 return 0;
 101
 102         default:
 103                 panic("Bad register in putreg(): %d\n", regno);
 104         }
 105
 106         child->thread.regs.regs.gp[reg_offsets[regno >> 3]] = value;
 107         return 0;
 108 }
 109
 110 int poke_user(struct task_struct *child, long addr, long data)
 111 {
 112         if ((addr & 3) || addr < 0)
 113                 return -EIO;
 114
 115         if (addr < MAX_REG_OFFSET)
 116                 return putreg(child, addr, data);
 117         else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
 118                 (addr <= offsetof(struct user, u_debugreg[7]))) {
 119                 addr -= offsetof(struct user, u_debugreg[0]);
 120                 addr = addr >> 3;
 121                 if ((addr == 4) || (addr == 5))
 122                         return -EIO;
 123                 child->thread.arch.debugregs[addr] = data;
 124                 return 0;
 125         }
 126         return -EIO;
 127 }
 128
 129 unsigned long getreg(struct task_struct *child, int regno)
 130 {
 131         unsigned long mask = ~0UL;
 132
 133         switch (regno) {
 134         case R8:
 135         case R9:
 136         case R10:
 137         case R11:
 138         case R12:
 139         case R13:
 140         case R14:
 141         case R15:
 142         case RIP:
 143         case RSP:
 144         case RAX:
 145         case RBX:
 146         case RCX:
 147         case RDX:
 148         case RSI:
 149         case RDI:
 150         case RBP:
 151         case ORIG_RAX:
 152         case EFLAGS:
 153         case FS_BASE:
 154         case GS_BASE:
 155                 break;
 156         case FS:
 157         case GS:
 158         case DS:
 159         case ES:
 160         case SS:
 161         case CS:
 162                 mask = 0xffff;
 163                 break;
 164         default:
 165                 panic("Bad register in getreg: %d\n", regno);
 166         }
 167         return mask & child->thread.regs.regs.gp[reg_offsets[regno >> 3]];
 168 }
 169
 170 int peek_user(struct task_struct *child, long addr, long data)
 171 {
 172         /* read the word at location addr in the USER area. */
 173         unsigned long tmp;
 174
 175         if ((addr & 3) || addr < 0)
 176                 return -EIO;
 177
 178         tmp = 0;  /* Default return condition */
 179         if (addr < MAX_REG_OFFSET)
 180                 tmp = getreg(child, addr);
 181         else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
 182                 (addr <= offsetof(struct user, u_debugreg[7]))) {
 183                 addr -= offsetof(struct user, u_debugreg[0]);
 184                 addr = addr >> 2;
 185                 tmp = child->thread.arch.debugregs[addr];
 186         }
 187         return put_user(tmp, (unsigned long *) data);
 188 }
 189
 190 /* XXX Mostly copied from sys-i386 */
 191 int is_syscall(unsigned long addr)
 192 {
 193         unsigned short instr;
 194         int n;
 195
 196         n = copy_from_user(&instr, (void __user *) addr, sizeof(instr));
 197         if (n) {
 198                 /*
 199                  * access_process_vm() grants access to vsyscall and stub,
 200                  * while copy_from_user doesn't. Maybe access_process_vm is
 201                  * slow, but that doesn't matter, since it will be called only
 202                  * in case of singlestepping, if copy_from_user failed.
 203                  */
 204                 n = access_process_vm(current, addr, &instr, sizeof(instr),
 205                                 FOLL_FORCE);
 206                 if (n != sizeof(instr)) {
 207                         printk("is_syscall : failed to read instruction from "
 208                                "0x%lx\n", addr);
 209                         return 1;
 210                 }
 211         }
 212         /* sysenter */
 213         return instr == 0x050f;
 214 }
 215
 216 static int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 217 {
 218         int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
 219         struct user_i387_struct fpregs;
 220
 221         err = save_i387_registers(userspace_pid[cpu],
 222                                   (unsigned long *) &fpregs);
 223         if (err)
 224                 return err;
 225
 226         n = copy_to_user(buf, &fpregs, sizeof(fpregs));
 227         if (n > 0)
 228                 return -EFAULT;
 229
 230         return n;
 231 }
 232
 233 static int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 234 {
 235         int n, cpu = ((struct thread_info *) child->stack)->cpu;
 236         struct user_i387_struct fpregs;
 237
 238         n = copy_from_user(&fpregs, buf, sizeof(fpregs));
 239         if (n > 0)
 240                 return -EFAULT;
 241
 242         return restore_i387_registers(userspace_pid[cpu],
 243                                       (unsigned long *) &fpregs);
 244 }
 245
 246 long subarch_ptrace(struct task_struct *child, long request,
 247                     unsigned long addr, unsigned long data)
 248 {
 249         int ret = -EIO;
 250         void __user *datap = (void __user *) data;
 251
 252         switch (request) {
 253         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 254                 ret = get_fpregs(datap, child);
 255                 break;
 256         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 257                 ret = set_fpregs(datap, child);
 258                 break;
 259         case PTRACE_ARCH_PRCTL:
 260                 /* XXX Calls ptrace on the host - needs some SMP thinking */
 261                 ret = arch_prctl(child, data, (void __user *) addr);
 262                 break;
 263         }
 264
 265         return ret;
 266 }