arch/x86/um/ptrace_32.c

   1 /*
   2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <linux/mm.h>
   7 #include <linux/sched.h>
   8 #include <asm/uaccess.h>
   9 #include <asm/ptrace-abi.h>
  10 #include <skas.h>
  11
  12 extern int arch_switch_tls(struct task_struct *to);
  13
  14 void arch_switch_to(struct task_struct *to)
  15 {
  16         int err = arch_switch_tls(to);
  17         if (!err)
  18                 return;
  19
  20         if (err != -EINVAL)
  21                 printk(KERN_WARNING "arch_switch_tls failed, errno %d, "
  22                        "not EINVAL\n", -err);
  23         else
  24                 printk(KERN_WARNING "arch_switch_tls failed, errno = EINVAL\n");
  25 }
  26
  27 int is_syscall(unsigned long addr)
  28 {
  29         unsigned short instr;
  30         int n;
  31
  32         n = copy_from_user(&instr, (void __user *) addr, sizeof(instr));
  33         if (n) {
  34                 /* access_process_vm() grants access to vsyscall and stub,
  35                  * while copy_from_user doesn't. Maybe access_process_vm is
  36                  * slow, but that doesn't matter, since it will be called only
  37                  * in case of singlestepping, if copy_from_user failed.
  38                  */
  39                 n = access_process_vm(current, addr, &instr, sizeof(instr), 0);
  40                 if (n != sizeof(instr)) {
  41                         printk(KERN_ERR "is_syscall : failed to read "
  42                                "instruction from 0x%lx\n", addr);
  43                         return 1;
  44                 }
  45         }
  46         /* int 0x80 or sysenter */
  47         return (instr == 0x80cd) || (instr == 0x340f);
  48 }
  49
  50 /* determines which flags the user has access to. */
  51 /* 1 = access 0 = no access */
  52 #define FLAG_MASK 0x00044dd5
  53
  54 static const int reg_offsets[] = {
  55         [EBX] = HOST_BX,
  56         [ECX] = HOST_CX,
  57         [EDX] = HOST_DX,
  58         [ESI] = HOST_SI,
  59         [EDI] = HOST_DI,
  60         [EBP] = HOST_BP,
  61         [EAX] = HOST_AX,
  62         [DS] = HOST_DS,
  63         [ES] = HOST_ES,
  64         [FS] = HOST_FS,
  65         [GS] = HOST_GS,
  66         [EIP] = HOST_IP,
  67         [CS] = HOST_CS,
  68         [EFL] = HOST_EFLAGS,
  69         [UESP] = HOST_SP,
  70         [SS] = HOST_SS,
  71         [ORIG_EAX] = HOST_ORIG_AX,
  72 };
  73
  74 int putreg(struct task_struct *child, int regno, unsigned long value)
  75 {
  76         regno >>= 2;
  77         switch (regno) {
  78         case EBX:
  79         case ECX:
  80         case EDX:
  81         case ESI:
  82         case EDI:
  83         case EBP:
  84         case EAX:
  85         case EIP:
  86         case UESP:
  87                 break;
  88         case ORIG_EAX:
  89                 /* Update the syscall number. */
  90                 UPT_SYSCALL_NR(&child->thread.regs.regs) = value;
  91                 break;
  92         case FS:
  93                 if (value && (value & 3) != 3)
  94                         return -EIO;
  95                 break;
  96         case GS:
  97                 if (value && (value & 3) != 3)
  98                         return -EIO;
  99                 break;
 100         case DS:
 101         case ES:
 102                 if (value && (value & 3) != 3)
 103                         return -EIO;
 104                 value &= 0xffff;
 105                 break;
 106         case SS:
 107         case CS:
 108                 if ((value & 3) != 3)
 109                         return -EIO;
 110                 value &= 0xffff;
 111                 break;
 112         case EFL:
 113                 value &= FLAG_MASK;
 114                 child->thread.regs.regs.gp[HOST_EFLAGS] |= value;
 115                 return 0;
 116         default :
 117                 panic("Bad register in putreg() : %d\n", regno);
 118         }
 119         child->thread.regs.regs.gp[reg_offsets[regno]] = value;
 120         return 0;
 121 }
 122
 123 int poke_user(struct task_struct *child, long addr, long data)
 124 {
 125         if ((addr & 3) || addr < 0)
 126                 return -EIO;
 127
 128         if (addr < MAX_REG_OFFSET)
 129                 return putreg(child, addr, data);
 130         else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
 131                  (addr <= offsetof(struct user, u_debugreg[7]))) {
 132                 addr -= offsetof(struct user, u_debugreg[0]);
 133                 addr = addr >> 2;
 134                 if ((addr == 4) || (addr == 5))
 135                         return -EIO;
 136                 child->thread.arch.debugregs[addr] = data;
 137                 return 0;
 138         }
 139         return -EIO;
 140 }
 141
 142 unsigned long getreg(struct task_struct *child, int regno)
 143 {
 144         unsigned long mask = ~0UL;
 145
 146         regno >>= 2;
 147         switch (regno) {
 148         case FS:
 149         case GS:
 150         case DS:
 151         case ES:
 152         case SS:
 153         case CS:
 154                 mask = 0xffff;
 155                 break;
 156         case EIP:
 157         case UESP:
 158         case EAX:
 159         case EBX:
 160         case ECX:
 161         case EDX:
 162         case ESI:
 163         case EDI:
 164         case EBP:
 165         case EFL:
 166         case ORIG_EAX:
 167                 break;
 168         default:
 169                 panic("Bad register in getreg() : %d\n", regno);
 170         }
 171         return mask & child->thread.regs.regs.gp[reg_offsets[regno]];
 172 }
 173
 174 /* read the word at location addr in the USER area. */
 175 int peek_user(struct task_struct *child, long addr, long data)
 176 {
 177         unsigned long tmp;
 178
 179         if ((addr & 3) || addr < 0)
 180                 return -EIO;
 181
 182         tmp = 0;  /* Default return condition */
 183         if (addr < MAX_REG_OFFSET) {
 184                 tmp = getreg(child, addr);
 185         }
 186         else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
 187                  (addr <= offsetof(struct user, u_debugreg[7]))) {
 188                 addr -= offsetof(struct user, u_debugreg[0]);
 189                 addr = addr >> 2;
 190                 tmp = child->thread.arch.debugregs[addr];
 191         }
 192         return put_user(tmp, (unsigned long __user *) data);
 193 }
 194
 195 static int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 196 {
 197         int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
 198         struct user_i387_struct fpregs;
 199
 200         err = save_i387_registers(userspace_pid[cpu],
 201                                   (unsigned long *) &fpregs);
 202         if (err)
 203                 return err;
 204
 205         n = copy_to_user(buf, &fpregs, sizeof(fpregs));
 206         if(n > 0)
 207                 return -EFAULT;
 208
 209         return n;
 210 }
 211
 212 static int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 213 {
 214         int n, cpu = ((struct thread_info *) child->stack)->cpu;
 215         struct user_i387_struct fpregs;
 216
 217         n = copy_from_user(&fpregs, buf, sizeof(fpregs));
 218         if (n > 0)
 219                 return -EFAULT;
 220
 221         return restore_i387_registers(userspace_pid[cpu],
 222                                     (unsigned long *) &fpregs);
 223 }
 224
 225 static int get_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
 226 {
 227         int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
 228         struct user_fxsr_struct fpregs;
 229
 230         err = save_fpx_registers(userspace_pid[cpu], (unsigned long *) &fpregs);
 231         if (err)
 232                 return err;
 233
 234         n = copy_to_user(buf, &fpregs, sizeof(fpregs));
 235         if(n > 0)
 236                 return -EFAULT;
 237
 238         return n;
 239 }
 240
 241 static int set_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
 242 {
 243         int n, cpu = ((struct thread_info *) child->stack)->cpu;
 244         struct user_fxsr_struct fpregs;
 245
 246         n = copy_from_user(&fpregs, buf, sizeof(fpregs));
 247         if (n > 0)
 248                 return -EFAULT;
 249
 250         return restore_fpx_registers(userspace_pid[cpu],
 251                                      (unsigned long *) &fpregs);
 252 }
 253
 254 long subarch_ptrace(struct task_struct *child, long request,
 255                     unsigned long addr, unsigned long data)
 256 {
 257         int ret = -EIO;
 258         void __user *datap = (void __user *) data;
 259         switch (request) {
 260         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 261                 ret = get_fpregs(datap, child);
 262                 break;
 263         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 264                 ret = set_fpregs(datap, child);
 265                 break;
 266         case PTRACE_GETFPXREGS: /* Get the child FPU state. */
 267                 ret = get_fpxregs(datap, child);
 268                 break;
 269         case PTRACE_SETFPXREGS: /* Set the child FPU state. */
 270                 ret = set_fpxregs(datap, child);
 271                 break;
 272         default:
 273                 ret = -EIO;
 274         }
 275         return ret;
 276 }