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 <linux/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),
  40                                 FOLL_FORCE);
  41                 if (n != sizeof(instr)) {
  42                         printk(KERN_ERR "is_syscall : failed to read "
  43                                "instruction from 0x%lx\n", addr);
  44                         return 1;
  45                 }
  46         }
  47         /* int 0x80 or sysenter */
  48         return (instr == 0x80cd) || (instr == 0x340f);
  49 }
  50
  51 /* determines which flags the user has access to. */
  52 /* 1 = access 0 = no access */
  53 #define FLAG_MASK 0x00044dd5
  54
  55 static const int reg_offsets[] = {
  56         [EBX] = HOST_BX,
  57         [ECX] = HOST_CX,
  58         [EDX] = HOST_DX,
  59         [ESI] = HOST_SI,
  60         [EDI] = HOST_DI,
  61         [EBP] = HOST_BP,
  62         [EAX] = HOST_AX,
  63         [DS] = HOST_DS,
  64         [ES] = HOST_ES,
  65         [FS] = HOST_FS,
  66         [GS] = HOST_GS,
  67         [EIP] = HOST_IP,
  68         [CS] = HOST_CS,
  69         [EFL] = HOST_EFLAGS,
  70         [UESP] = HOST_SP,
  71         [SS] = HOST_SS,
  72         [ORIG_EAX] = HOST_ORIG_AX,
  73 };
  74
  75 int putreg(struct task_struct *child, int regno, unsigned long value)
  76 {
  77         regno >>= 2;
  78         switch (regno) {
  79         case EBX:
  80         case ECX:
  81         case EDX:
  82         case ESI:
  83         case EDI:
  84         case EBP:
  85         case EAX:
  86         case EIP:
  87         case UESP:
  88                 break;
  89         case ORIG_EAX:
  90                 /* Update the syscall number. */
  91                 UPT_SYSCALL_NR(&child->thread.regs.regs) = value;
  92                 break;
  93         case FS:
  94                 if (value && (value & 3) != 3)
  95                         return -EIO;
  96                 break;
  97         case GS:
  98                 if (value && (value & 3) != 3)
  99                         return -EIO;
 100                 break;
 101         case DS:
 102         case ES:
 103                 if (value && (value & 3) != 3)
 104                         return -EIO;
 105                 value &= 0xffff;
 106                 break;
 107         case SS:
 108         case CS:
 109                 if ((value & 3) != 3)
 110                         return -EIO;
 111                 value &= 0xffff;
 112                 break;
 113         case EFL:
 114                 value &= FLAG_MASK;
 115                 child->thread.regs.regs.gp[HOST_EFLAGS] |= value;
 116                 return 0;
 117         default :
 118                 panic("Bad register in putreg() : %d\n", regno);
 119         }
 120         child->thread.regs.regs.gp[reg_offsets[regno]] = value;
 121         return 0;
 122 }
 123
 124 int poke_user(struct task_struct *child, long addr, long data)
 125 {
 126         if ((addr & 3) || addr < 0)
 127                 return -EIO;
 128
 129         if (addr < MAX_REG_OFFSET)
 130                 return putreg(child, addr, data);
 131         else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
 132                  (addr <= offsetof(struct user, u_debugreg[7]))) {
 133                 addr -= offsetof(struct user, u_debugreg[0]);
 134                 addr = addr >> 2;
 135                 if ((addr == 4) || (addr == 5))
 136                         return -EIO;
 137                 child->thread.arch.debugregs[addr] = data;
 138                 return 0;
 139         }
 140         return -EIO;
 141 }
 142
 143 unsigned long getreg(struct task_struct *child, int regno)
 144 {
 145         unsigned long mask = ~0UL;
 146
 147         regno >>= 2;
 148         switch (regno) {
 149         case FS:
 150         case GS:
 151         case DS:
 152         case ES:
 153         case SS:
 154         case CS:
 155                 mask = 0xffff;
 156                 break;
 157         case EIP:
 158         case UESP:
 159         case EAX:
 160         case EBX:
 161         case ECX:
 162         case EDX:
 163         case ESI:
 164         case EDI:
 165         case EBP:
 166         case EFL:
 167         case ORIG_EAX:
 168                 break;
 169         default:
 170                 panic("Bad register in getreg() : %d\n", regno);
 171         }
 172         return mask & child->thread.regs.regs.gp[reg_offsets[regno]];
 173 }
 174
 175 /* read the word at location addr in the USER area. */
 176 int peek_user(struct task_struct *child, long addr, long data)
 177 {
 178         unsigned long tmp;
 179
 180         if ((addr & 3) || addr < 0)
 181                 return -EIO;
 182
 183         tmp = 0;  /* Default return condition */
 184         if (addr < MAX_REG_OFFSET) {
 185                 tmp = getreg(child, addr);
 186         }
 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 __user *) data);
 194 }
 195
 196 static int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 197 {
 198         int err, n, cpu = task_cpu(child);
 199         struct user_i387_struct fpregs;
 200
 201         err = save_i387_registers(userspace_pid[cpu],
 202                                   (unsigned long *) &fpregs);
 203         if (err)
 204                 return err;
 205
 206         n = copy_to_user(buf, &fpregs, sizeof(fpregs));
 207         if(n > 0)
 208                 return -EFAULT;
 209
 210         return n;
 211 }
 212
 213 static int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 214 {
 215         int n, cpu = task_cpu(child);
 216         struct user_i387_struct fpregs;
 217
 218         n = copy_from_user(&fpregs, buf, sizeof(fpregs));
 219         if (n > 0)
 220                 return -EFAULT;
 221
 222         return restore_i387_registers(userspace_pid[cpu],
 223                                     (unsigned long *) &fpregs);
 224 }
 225
 226 static int get_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
 227 {
 228         int err, n, cpu = task_cpu(child);
 229         struct user_fxsr_struct fpregs;
 230
 231         err = save_fpx_registers(userspace_pid[cpu], (unsigned long *) &fpregs);
 232         if (err)
 233                 return err;
 234
 235         n = copy_to_user(buf, &fpregs, sizeof(fpregs));
 236         if(n > 0)
 237                 return -EFAULT;
 238
 239         return n;
 240 }
 241
 242 static int set_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
 243 {
 244         int n, cpu = task_cpu(child);
 245         struct user_fxsr_struct fpregs;
 246
 247         n = copy_from_user(&fpregs, buf, sizeof(fpregs));
 248         if (n > 0)
 249                 return -EFAULT;
 250
 251         return restore_fpx_registers(userspace_pid[cpu],
 252                                      (unsigned long *) &fpregs);
 253 }
 254
 255 long subarch_ptrace(struct task_struct *child, long request,
 256                     unsigned long addr, unsigned long data)
 257 {
 258         int ret = -EIO;
 259         void __user *datap = (void __user *) data;
 260         switch (request) {
 261         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 262                 ret = get_fpregs(datap, child);
 263                 break;
 264         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 265                 ret = set_fpregs(datap, child);
 266                 break;
 267         case PTRACE_GETFPXREGS: /* Get the child FPU state. */
 268                 ret = get_fpxregs(datap, child);
 269                 break;
 270         case PTRACE_SETFPXREGS: /* Set the child FPU state. */
 271                 ret = set_fpxregs(datap, child);
 272                 break;
 273         default:
 274                 ret = -EIO;
 275         }
 276         return ret;
 277 }