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 #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
 118 int 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 >> 2;
 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
 137 unsigned 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
 181 int 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 */
 202 int 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
 227 static 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
 244 static 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
 257 long 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 }