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 };
  72
  73 int putreg(struct task_struct *child, int regno, unsigned long value)
  74 {
  75         regno >>= 2;
  76         switch (regno) {
  77         case EBX:
  78         case ECX:
  79         case EDX:
  80         case ESI:
  81         case EDI:
  82         case EBP:
  83         case EAX:
  84         case EIP:
  85         case UESP:
  86                 break;
  87         case FS:
  88                 if (value && (value & 3) != 3)
  89                         return -EIO;
  90                 break;
  91         case GS:
  92                 if (value && (value & 3) != 3)
  93                         return -EIO;
  94                 break;
  95         case DS:
  96         case ES:
  97                 if (value && (value & 3) != 3)
  98                         return -EIO;
  99                 value &= 0xffff;
 100                 break;
 101         case SS:
 102         case CS:
 103                 if ((value & 3) != 3)
 104                         return -EIO;
 105                 value &= 0xffff;
 106                 break;
 107         case EFL:
 108                 value &= FLAG_MASK;
 109                 child->thread.regs.regs.gp[HOST_EFLAGS] |= value;
 110                 return 0;
 111         case ORIG_EAX:
 112                 child->thread.regs.regs.syscall = value;
 113                 return 0;
 114         default :
 115                 panic("Bad register in putreg() : %d\n", regno);
 116         }
 117         child->thread.regs.regs.gp[reg_offsets[regno]] = value;
 118         return 0;
 119 }
 120
 121 int poke_user(struct task_struct *child, long addr, long data)
 122 {
 123         if ((addr & 3) || addr < 0)
 124                 return -EIO;
 125
 126         if (addr < MAX_REG_OFFSET)
 127                 return putreg(child, addr, data);
 128         else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
 129                  (addr <= offsetof(struct user, u_debugreg[7]))) {
 130                 addr -= offsetof(struct user, u_debugreg[0]);
 131                 addr = addr >> 2;
 132                 if ((addr == 4) || (addr == 5))
 133                         return -EIO;
 134                 child->thread.arch.debugregs[addr] = data;
 135                 return 0;
 136         }
 137         return -EIO;
 138 }
 139
 140 unsigned long getreg(struct task_struct *child, int regno)
 141 {
 142         unsigned long mask = ~0UL;
 143
 144         regno >>= 2;
 145         switch (regno) {
 146         case ORIG_EAX:
 147                 return child->thread.regs.regs.syscall;
 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                 break;
 167         default:
 168                 panic("Bad register in getreg() : %d\n", regno);
 169         }
 170         return mask & child->thread.regs.regs.gp[reg_offsets[regno]];
 171 }
 172
 173 /* read the word at location addr in the USER area. */
 174 int peek_user(struct task_struct *child, long addr, long data)
 175 {
 176         unsigned long tmp;
 177
 178         if ((addr & 3) || addr < 0)
 179                 return -EIO;
 180
 181         tmp = 0;  /* Default return condition */
 182         if (addr < MAX_REG_OFFSET) {
 183                 tmp = getreg(child, addr);
 184         }
 185         else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
 186                  (addr <= offsetof(struct user, u_debugreg[7]))) {
 187                 addr -= offsetof(struct user, u_debugreg[0]);
 188                 addr = addr >> 2;
 189                 tmp = child->thread.arch.debugregs[addr];
 190         }
 191         return put_user(tmp, (unsigned long __user *) data);
 192 }
 193
 194 static int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 195 {
 196         int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
 197         struct user_i387_struct fpregs;
 198
 199         err = save_fp_registers(userspace_pid[cpu], (unsigned long *) &fpregs);
 200         if (err)
 201                 return err;
 202
 203         n = copy_to_user(buf, &fpregs, sizeof(fpregs));
 204         if(n > 0)
 205                 return -EFAULT;
 206
 207         return n;
 208 }
 209
 210 static int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 211 {
 212         int n, cpu = ((struct thread_info *) child->stack)->cpu;
 213         struct user_i387_struct fpregs;
 214
 215         n = copy_from_user(&fpregs, buf, sizeof(fpregs));
 216         if (n > 0)
 217                 return -EFAULT;
 218
 219         return restore_fp_registers(userspace_pid[cpu],
 220                                     (unsigned long *) &fpregs);
 221 }
 222
 223 static int get_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
 224 {
 225         int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
 226         struct user_fxsr_struct fpregs;
 227
 228         err = save_fpx_registers(userspace_pid[cpu], (unsigned long *) &fpregs);
 229         if (err)
 230                 return err;
 231
 232         n = copy_to_user(buf, &fpregs, sizeof(fpregs));
 233         if(n > 0)
 234                 return -EFAULT;
 235
 236         return n;
 237 }
 238
 239 static int set_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
 240 {
 241         int n, cpu = ((struct thread_info *) child->stack)->cpu;
 242         struct user_fxsr_struct fpregs;
 243
 244         n = copy_from_user(&fpregs, buf, sizeof(fpregs));
 245         if (n > 0)
 246                 return -EFAULT;
 247
 248         return restore_fpx_registers(userspace_pid[cpu],
 249                                      (unsigned long *) &fpregs);
 250 }
 251
 252 long subarch_ptrace(struct task_struct *child, long request,
 253                     unsigned long addr, unsigned long data)
 254 {
 255         int ret = -EIO;
 256         void __user *datap = (void __user *) data;
 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_GETFPXREGS: /* Get the child FPU state. */
 265                 ret = get_fpxregs(datap, child);
 266                 break;
 267         case PTRACE_SETFPXREGS: /* Set the child FPU state. */
 268                 ret = set_fpxregs(datap, child);
 269                 break;
 270         default:
 271                 ret = -EIO;
 272         }
 273         return ret;
 274 }