LXR linux/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
  11extern int arch_switch_tls(struct task_struct *to);
  12
  13void 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
  26int 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
  53int 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
  88int 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
 107unsigned 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. */
 128int 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
 148int 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
 164int 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
 177int 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
 193int 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
 206long subarch_ptrace(struct task_struct *child, long request, long addr,
 207                    long data)
 208{
 209        return -EIO;
 210}
 211