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 <asm/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 #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         case ORIG_RAX:
  82                 break;
  83
  84         case FS:
  85         case GS:
  86         case DS:
  87         case ES:
  88         case SS:
  89         case CS:
  90                 if (value && (value & 3) != 3)
  91                         return -EIO;
  92                 value &= 0xffff;
  93                 break;
  94
  95         case FS_BASE:
  96         case GS_BASE:
  97                 if (!((value >> 48) == 0 || (value >> 48) == 0xffff))
  98                         return -EIO;
  99                 break;
 100
 101         case EFLAGS:
 102                 value &= FLAG_MASK;
 103                 child->thread.regs.regs.gp[HOST_EFLAGS] |= value;
 104                 return 0;
 105
 106         default:
 107                 panic("Bad register in putreg(): %d\n", regno);
 108         }
 109
 110         child->thread.regs.regs.gp[reg_offsets[regno >> 3]] = value;
 111         return 0;
 112 }
 113
 114 int poke_user(struct task_struct *child, long addr, long data)
 115 {
 116         if ((addr & 3) || addr < 0)
 117                 return -EIO;
 118
 119         if (addr < MAX_REG_OFFSET)
 120                 return putreg(child, addr, data);
 121         else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
 122                 (addr <= offsetof(struct user, u_debugreg[7]))) {
 123                 addr -= offsetof(struct user, u_debugreg[0]);
 124                 addr = addr >> 2;
 125                 if ((addr == 4) || (addr == 5))
 126                         return -EIO;
 127                 child->thread.arch.debugregs[addr] = data;
 128                 return 0;
 129         }
 130         return -EIO;
 131 }
 132
 133 unsigned long getreg(struct task_struct *child, int regno)
 134 {
 135         unsigned long mask = ~0UL;
 136 #ifdef TIF_IA32
 137         if (test_tsk_thread_flag(child, TIF_IA32))
 138                 mask = 0xffffffff;
 139 #endif
 140         switch (regno) {
 141         case R8:
 142         case R9:
 143         case R10:
 144         case R11:
 145         case R12:
 146         case R13:
 147         case R14:
 148         case R15:
 149         case RIP:
 150         case RSP:
 151         case RAX:
 152         case RBX:
 153         case RCX:
 154         case RDX:
 155         case RSI:
 156         case RDI:
 157         case RBP:
 158         case ORIG_RAX:
 159         case EFLAGS:
 160         case FS_BASE:
 161         case GS_BASE:
 162                 break;
 163         case FS:
 164         case GS:
 165         case DS:
 166         case ES:
 167         case SS:
 168         case CS:
 169                 mask = 0xffff;
 170                 break;
 171         default:
 172                 panic("Bad register in getreg: %d\n", regno);
 173         }
 174         return mask & child->thread.regs.regs.gp[reg_offsets[regno >> 3]];
 175 }
 176
 177 int peek_user(struct task_struct *child, long addr, long data)
 178 {
 179         /* read the word at location addr in the USER area. */
 180         unsigned long tmp;
 181
 182         if ((addr & 3) || addr < 0)
 183                 return -EIO;
 184
 185         tmp = 0;  /* Default return condition */
 186         if (addr < MAX_REG_OFFSET)
 187                 tmp = getreg(child, addr);
 188         else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
 189                 (addr <= offsetof(struct user, u_debugreg[7]))) {
 190                 addr -= offsetof(struct user, u_debugreg[0]);
 191                 addr = addr >> 2;
 192                 tmp = child->thread.arch.debugregs[addr];
 193         }
 194         return put_user(tmp, (unsigned long *) data);
 195 }
 196
 197 /* XXX Mostly copied from sys-i386 */
 198 int is_syscall(unsigned long addr)
 199 {
 200         unsigned short instr;
 201         int n;
 202
 203         n = copy_from_user(&instr, (void __user *) addr, sizeof(instr));
 204         if (n) {
 205                 /*
 206                  * access_process_vm() grants access to vsyscall and stub,
 207                  * while copy_from_user doesn't. Maybe access_process_vm is
 208                  * slow, but that doesn't matter, since it will be called only
 209                  * in case of singlestepping, if copy_from_user failed.
 210                  */
 211                 n = access_process_vm(current, addr, &instr, sizeof(instr), 0);
 212                 if (n != sizeof(instr)) {
 213                         printk("is_syscall : failed to read instruction from "
 214                                "0x%lx\n", addr);
 215                         return 1;
 216                 }
 217         }
 218         /* sysenter */
 219         return instr == 0x050f;
 220 }
 221
 222 static int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 223 {
 224         int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
 225         struct user_i387_struct fpregs;
 226
 227         err = save_i387_registers(userspace_pid[cpu],
 228                                   (unsigned long *) &fpregs);
 229         if (err)
 230                 return err;
 231
 232         n = copy_to_user(buf, &fpregs, sizeof(fpregs));
 233         if (n > 0)
 234                 return -EFAULT;
 235
 236         return n;
 237 }
 238
 239 static int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 240 {
 241         int n, cpu = ((struct thread_info *) child->stack)->cpu;
 242         struct user_i387_struct fpregs;
 243
 244         n = copy_from_user(&fpregs, buf, sizeof(fpregs));
 245         if (n > 0)
 246                 return -EFAULT;
 247
 248         return restore_i387_registers(userspace_pid[cpu],
 249                                       (unsigned long *) &fpregs);
 250 }
 251
 252 long subarch_ptrace(struct task_struct *child, long request,
 253                     unsigned long addr, unsigned long data)
 254 {
 255         int ret = -EIO;
 256         void __user *datap = (void __user *) data;
 257
 258         switch (request) {
 259         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 260                 ret = get_fpregs(datap, child);
 261                 break;
 262         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 263                 ret = set_fpregs(datap, child);
 264                 break;
 265         case PTRACE_ARCH_PRCTL:
 266                 /* XXX Calls ptrace on the host - needs some SMP thinking */
 267                 ret = arch_prctl(child, data, (void __user *) addr);
 268                 break;
 269         }
 270
 271         return ret;
 272 }