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 int putreg(struct task_struct *child, int regno, unsigned long value)
  54 {
  55         regno >>= 2;
  56         switch (regno) {
  57         case FS:
  58                 if (value && (value & 3) != 3)
  59                         return -EIO;
  60                 PT_REGS_FS(&child->thread.regs) = value;
  61                 return 0;
  62         case GS:
  63                 if (value && (value & 3) != 3)
  64                         return -EIO;
  65                 PT_REGS_GS(&child->thread.regs) = value;
  66                 return 0;
  67         case DS:
  68         case ES:
  69                 if (value && (value & 3) != 3)
  70                         return -EIO;
  71                 value &= 0xffff;
  72                 break;
  73         case SS:
  74         case CS:
  75                 if ((value & 3) != 3)
  76                         return -EIO;
  77                 value &= 0xffff;
  78                 break;
  79         case EFL:
  80                 value &= FLAG_MASK;
  81                 value |= PT_REGS_EFLAGS(&child->thread.regs);
  82                 break;
  83         }
  84         PT_REGS_SET(&child->thread.regs, regno, value);
  85         return 0;
  86 }
  87
  88 int poke_user(struct task_struct *child, long addr, long data)
  89 {
  90         if ((addr & 3) || addr < 0)
  91                 return -EIO;
  92
  93         if (addr < MAX_REG_OFFSET)
  94                 return putreg(child, addr, data);
  95         else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
  96                  (addr <= offsetof(struct user, u_debugreg[7]))) {
  97                 addr -= offsetof(struct user, u_debugreg[0]);
  98                 addr = addr >> 2;
  99                 if ((addr == 4) || (addr == 5))
 100                         return -EIO;
 101                 child->thread.arch.debugregs[addr] = data;
 102                 return 0;
 103         }
 104         return -EIO;
 105 }
 106
 107 unsigned long getreg(struct task_struct *child, int regno)
 108 {
 109         unsigned long retval = ~0UL;
 110
 111         regno >>= 2;
 112         switch (regno) {
 113         case FS:
 114         case GS:
 115         case DS:
 116         case ES:
 117         case SS:
 118         case CS:
 119                 retval = 0xffff;
 120                 /* fall through */
 121         default:
 122                 retval &= PT_REG(&child->thread.regs, regno);
 123         }
 124         return retval;
 125 }
 126
 127 /* read the word at location addr in the USER area. */
 128 int peek_user(struct task_struct *child, long addr, long data)
 129 {
 130         unsigned long tmp;
 131
 132         if ((addr & 3) || addr < 0)
 133                 return -EIO;
 134
 135         tmp = 0;  /* Default return condition */
 136         if (addr < MAX_REG_OFFSET) {
 137                 tmp = getreg(child, addr);
 138         }
 139         else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
 140                  (addr <= offsetof(struct user, u_debugreg[7]))) {
 141                 addr -= offsetof(struct user, u_debugreg[0]);
 142                 addr = addr >> 2;
 143                 tmp = child->thread.arch.debugregs[addr];
 144         }
 145         return put_user(tmp, (unsigned long __user *) data);
 146 }
 147
 148 int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 149 {
 150         int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
 151         struct user_i387_struct fpregs;
 152
 153         err = save_fp_registers(userspace_pid[cpu], (unsigned long *) &fpregs);
 154         if (err)
 155                 return err;
 156
 157         n = copy_to_user(buf, &fpregs, sizeof(fpregs));
 158         if(n > 0)
 159                 return -EFAULT;
 160
 161         return n;
 162 }
 163
 164 int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 165 {
 166         int n, cpu = ((struct thread_info *) child->stack)->cpu;
 167         struct user_i387_struct fpregs;
 168
 169         n = copy_from_user(&fpregs, buf, sizeof(fpregs));
 170         if (n > 0)
 171                 return -EFAULT;
 172
 173         return restore_fp_registers(userspace_pid[cpu],
 174                                     (unsigned long *) &fpregs);
 175 }
 176
 177 int get_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
 178 {
 179         int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
 180         struct user_fxsr_struct fpregs;
 181
 182         err = save_fpx_registers(userspace_pid[cpu], (unsigned long *) &fpregs);
 183         if (err)
 184                 return err;
 185
 186         n = copy_to_user(buf, &fpregs, sizeof(fpregs));
 187         if(n > 0)
 188                 return -EFAULT;
 189
 190         return n;
 191 }
 192
 193 int set_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
 194 {
 195         int n, cpu = ((struct thread_info *) child->stack)->cpu;
 196         struct user_fxsr_struct fpregs;
 197
 198         n = copy_from_user(&fpregs, buf, sizeof(fpregs));
 199         if (n > 0)
 200                 return -EFAULT;
 201
 202         return restore_fpx_registers(userspace_pid[cpu],
 203                                      (unsigned long *) &fpregs);
 204 }
 205
 206 long subarch_ptrace(struct task_struct *child, long request, long addr,
 207                     long data)
 208 {
 209         return -EIO;
 210 }