arch/um/sys-i386/ptrace.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 "skas.h"
  10
  11 extern int arch_switch_tls(struct task_struct *to);
  12
  13 void arch_switch_to(struct task_struct *to)
  14 {
  15         int err = arch_switch_tls(to);
  16         if (!err)
  17                 return;
  18
  19         if (err != -EINVAL)
  20                 printk(KERN_WARNING "arch_switch_tls failed, errno %d, "
  21                        "not EINVAL\n", -err);
  22         else
  23                 printk(KERN_WARNING "arch_switch_tls failed, errno = EINVAL\n");
  24 }
  25
  26 int is_syscall(unsigned long addr)
  27 {
  28         unsigned short instr;
  29         int n;
  30
  31         n = copy_from_user(&instr, (void __user *) addr, sizeof(instr));
  32         if (n) {
  33                 /* access_process_vm() grants access to vsyscall and stub,
  34                  * while copy_from_user doesn't. Maybe access_process_vm is
  35                  * slow, but that doesn't matter, since it will be called only
  36                  * in case of singlestepping, if copy_from_user failed.
  37                  */
  38                 n = access_process_vm(current, addr, &instr, sizeof(instr), 0);
  39                 if (n != sizeof(instr)) {
  40                         printk(KERN_ERR "is_syscall : failed to read "
  41                                "instruction from 0x%lx\n", addr);
  42                         return 1;
  43                 }
  44         }
  45         /* int 0x80 or sysenter */
  46         return (instr == 0x80cd) || (instr == 0x340f);
  47 }
  48
  49 /* determines which flags the user has access to. */
  50 /* 1 = access 0 = no access */
  51 #define FLAG_MASK 0x00044dd5
  52
  53 static const int reg_offsets[] = {
  54         [EBX] = HOST_EBX,
  55         [ECX] = HOST_ECX,
  56         [EDX] = HOST_EDX,
  57         [ESI] = HOST_ESI,
  58         [EDI] = HOST_EDI,
  59         [EBP] = HOST_EBP,
  60         [EAX] = HOST_EAX,
  61         [DS] = HOST_DS,
  62         [ES] = HOST_ES,
  63         [FS] = HOST_FS,
  64         [GS] = HOST_GS,
  65         [EIP] = HOST_IP,
  66         [CS] = HOST_CS,
  67         [EFL] = HOST_EFLAGS,
  68         [UESP] = HOST_SP,
  69         [SS] = HOST_SS,
  70 };
  71
  72 int putreg(struct task_struct *child, int regno, unsigned long value)
  73 {
  74         regno >>= 2;
  75         switch (regno) {
  76         case EBX:
  77         case ECX:
  78         case EDX:
  79         case ESI:
  80         case EDI:
  81         case EBP:
  82         case EAX:
  83         case EIP:
  84         case UESP:
  85                 break;
  86         case FS:
  87                 if (value && (value & 3) != 3)
  88                         return -EIO;
  89                 break;
  90         case GS:
  91                 if (value && (value & 3) != 3)
  92                         return -EIO;
  93                 break;
  94         case DS:
  95         case ES:
  96                 if (value && (value & 3) != 3)
  97                         return -EIO;
  98                 value &= 0xffff;
  99                 break;
 100         case SS:
 101         case CS:
 102                 if ((value & 3) != 3)
 103                         return -EIO;
 104                 value &= 0xffff;
 105                 break;
 106         case EFL:
 107                 value &= FLAG_MASK;
 108                 child->thread.regs.regs.gp[HOST_EFLAGS] |= value;
 109                 return 0;
 110         case ORIG_EAX:
 111                 child->thread.regs.regs.syscall = value;
 112                 return 0;
 113         default :
 114                 panic("Bad register in putreg() : %d\n", regno);
 115         }
 116         child->thread.regs.regs.gp[reg_offsets[regno]] = value;
 117         return 0;
 118 }
 119
 120 int poke_user(struct task_struct *child, long addr, long data)
 121 {
 122         if ((addr & 3) || addr < 0)
 123                 return -EIO;
 124
 125         if (addr < MAX_REG_OFFSET)
 126                 return putreg(child, addr, data);
 127         else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
 128                  (addr <= offsetof(struct user, u_debugreg[7]))) {
 129                 addr -= offsetof(struct user, u_debugreg[0]);
 130                 addr = addr >> 2;
 131                 if ((addr == 4) || (addr == 5))
 132                         return -EIO;
 133                 child->thread.arch.debugregs[addr] = data;
 134                 return 0;
 135         }
 136         return -EIO;
 137 }
 138
 139 unsigned long getreg(struct task_struct *child, int regno)
 140 {
 141         unsigned long mask = ~0UL;
 142
 143         regno >>= 2;
 144         switch (regno) {
 145         case ORIG_EAX:
 146                 return child->thread.regs.regs.syscall;
 147         case FS:
 148         case GS:
 149         case DS:
 150         case ES:
 151         case SS:
 152         case CS:
 153                 mask = 0xffff;
 154                 break;
 155         case EIP:
 156         case UESP:
 157         case EAX:
 158         case EBX:
 159         case ECX:
 160         case EDX:
 161         case ESI:
 162         case EDI:
 163         case EBP:
 164         case EFL:
 165                 break;
 166         default:
 167                 panic("Bad register in getreg() : %d\n", regno);
 168         }
 169         return mask & child->thread.regs.regs.gp[reg_offsets[regno]];
 170 }
 171
 172 /* read the word at location addr in the USER area. */
 173 int peek_user(struct task_struct *child, long addr, long data)
 174 {
 175         unsigned long tmp;
 176
 177         if ((addr & 3) || addr < 0)
 178                 return -EIO;
 179
 180         tmp = 0;  /* Default return condition */
 181         if (addr < MAX_REG_OFFSET) {
 182                 tmp = getreg(child, addr);
 183         }
 184         else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
 185                  (addr <= offsetof(struct user, u_debugreg[7]))) {
 186                 addr -= offsetof(struct user, u_debugreg[0]);
 187                 addr = addr >> 2;
 188                 tmp = child->thread.arch.debugregs[addr];
 189         }
 190         return put_user(tmp, (unsigned long __user *) data);
 191 }
 192
 193 static int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 194 {
 195         int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
 196         struct user_i387_struct fpregs;
 197
 198         err = save_fp_registers(userspace_pid[cpu], (unsigned long *) &fpregs);
 199         if (err)
 200                 return err;
 201
 202         n = copy_to_user(buf, &fpregs, sizeof(fpregs));
 203         if(n > 0)
 204                 return -EFAULT;
 205
 206         return n;
 207 }
 208
 209 static int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 210 {
 211         int n, cpu = ((struct thread_info *) child->stack)->cpu;
 212         struct user_i387_struct fpregs;
 213
 214         n = copy_from_user(&fpregs, buf, sizeof(fpregs));
 215         if (n > 0)
 216                 return -EFAULT;
 217
 218         return restore_fp_registers(userspace_pid[cpu],
 219                                     (unsigned long *) &fpregs);
 220 }
 221
 222 static int get_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
 223 {
 224         int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
 225         struct user_fxsr_struct fpregs;
 226
 227         err = save_fpx_registers(userspace_pid[cpu], (unsigned long *) &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_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
 239 {
 240         int n, cpu = ((struct thread_info *) child->stack)->cpu;
 241         struct user_fxsr_struct fpregs;
 242
 243         n = copy_from_user(&fpregs, buf, sizeof(fpregs));
 244         if (n > 0)
 245                 return -EFAULT;
 246
 247         return restore_fpx_registers(userspace_pid[cpu],
 248                                      (unsigned long *) &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         switch (request) {
 257         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 258                 ret = get_fpregs(datap, child);
 259                 break;
 260         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 261                 ret = set_fpregs(datap, child);
 262                 break;
 263         case PTRACE_GETFPXREGS: /* Get the child FPU state. */
 264                 ret = get_fpxregs(datap, child);
 265                 break;
 266         case PTRACE_SETFPXREGS: /* Set the child FPU state. */
 267                 ret = set_fpxregs(datap, child);
 268                 break;
 269         default:
 270                 ret = -EIO;
 271         }
 272         return ret;
 273 }