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