LXR linux/arch/um/sys-x86

   1/*
   2 * Copyright 2003 PathScale, Inc.
   3 * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   4 *
   5 * Licensed under the GPL
   6 */
   7
   8#include <linux/mm.h>
   9#include <linux/sched.h>
  10#include <linux/errno.h>
  11#define __FRAME_OFFSETS
  12#include <asm/ptrace.h>
  13#include <asm/uaccess.h>
  14
  15/*
  16 * determines which flags the user has access to.
  17 * 1 = access 0 = no access
  18 */
  19#define FLAG_MASK 0x44dd5UL
  20
  21int putreg(struct task_struct *child, int regno, unsigned long value)
  22{
  23        unsigned long tmp;
  24
  25#ifdef TIF_IA32
  26        /*
  27         * Some code in the 64bit emulation may not be 64bit clean.
  28         * Don't take any chances.
  29         */
  30        if (test_tsk_thread_flag(child, TIF_IA32))
  31                value &= 0xffffffff;
  32#endif
  33        switch (regno) {
  34        case FS:
  35        case GS:
  36        case DS:
  37        case ES:
  38        case SS:
  39        case CS:
  40                if (value && (value & 3) != 3)
  41                        return -EIO;
  42                value &= 0xffff;
  43                break;
  44
  45        case FS_BASE:
  46        case GS_BASE:
  47                if (!((value >> 48) == 0 || (value >> 48) == 0xffff))
  48                        return -EIO;
  49                break;
  50
  51        case EFLAGS:
  52                value &= FLAG_MASK;
  53                tmp = PT_REGS_EFLAGS(&child->thread.regs) & ~FLAG_MASK;
  54                value |= tmp;
  55                break;
  56        }
  57
  58        PT_REGS_SET(&child->thread.regs, regno, value);
  59        return 0;
  60}
  61
  62int poke_user(struct task_struct *child, long addr, long data)
  63{
  64        if ((addr & 3) || addr < 0)
  65                return -EIO;
  66
  67        if (addr < MAX_REG_OFFSET)
  68                return putreg(child, addr, data);
  69        else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
  70                (addr <= offsetof(struct user, u_debugreg[7]))) {
  71                addr -= offsetof(struct user, u_debugreg[0]);
  72                addr = addr >> 2;
  73                if ((addr == 4) || (addr == 5))
  74                        return -EIO;
  75                child->thread.arch.debugregs[addr] = data;
  76                return 0;
  77        }
  78        return -EIO;
  79}
  80
  81unsigned long getreg(struct task_struct *child, int regno)
  82{
  83        unsigned long retval = ~0UL;
  84        switch (regno) {
  85        case FS:
  86        case GS:
  87        case DS:
  88        case ES:
  89        case SS:
  90        case CS:
  91                retval = 0xffff;
  92                /* fall through */
  93        default:
  94                retval &= PT_REG(&child->thread.regs, regno);
  95#ifdef TIF_IA32
  96                if (test_tsk_thread_flag(child, TIF_IA32))
  97                        retval &= 0xffffffff;
  98#endif
  99        }
 100        return retval;
 101}
 102
 103int peek_user(struct task_struct *child, long addr, long data)
 104{
 105        /* read the word at location addr in the USER area. */
 106        unsigned long tmp;
 107
 108        if ((addr & 3) || addr < 0)
 109                return -EIO;
 110
 111        tmp = 0;  /* Default return condition */
 112        if (addr < MAX_REG_OFFSET)
 113                tmp = getreg(child, addr);
 114        else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
 115                (addr <= offsetof(struct user, u_debugreg[7]))) {
 116                addr -= offsetof(struct user, u_debugreg[0]);
 117                addr = addr >> 2;
 118                tmp = child->thread.arch.debugregs[addr];
 119        }
 120        return put_user(tmp, (unsigned long *) data);
 121}
 122
 123/* XXX Mostly copied from sys-i386 */
 124int is_syscall(unsigned long addr)
 125{
 126        unsigned short instr;
 127        int n;
 128
 129        n = copy_from_user(&instr, (void __user *) addr, sizeof(instr));
 130        if (n) {
 131                /*
 132                 * access_process_vm() grants access to vsyscall and stub,
 133                 * while copy_from_user doesn't. Maybe access_process_vm is
 134                 * slow, but that doesn't matter, since it will be called only
 135                 * in case of singlestepping, if copy_from_user failed.
 136                 */
 137                n = access_process_vm(current, addr, &instr, sizeof(instr), 0);
 138                if (n != sizeof(instr)) {
 139                        printk("is_syscall : failed to read instruction from "
 140                               "0x%lx\n", addr);
 141                        return 1;
 142                }
 143        }
 144        /* sysenter */
 145        return instr == 0x050f;
 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        long fpregs[HOST_FP_SIZE];
 152
 153        BUG_ON(sizeof(*buf) != sizeof(fpregs));
 154        err = save_fp_registers(userspace_pid[cpu], fpregs);
 155        if (err)
 156                return err;
 157
 158        n = copy_to_user(buf, fpregs, sizeof(fpregs));
 159        if (n > 0)
 160                return -EFAULT;
 161
 162        return n;
 163}
 164
 165int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
 166{
 167        int n, cpu = ((struct thread_info *) child->stack)->cpu;
 168        long fpregs[HOST_FP_SIZE];
 169
 170        BUG_ON(sizeof(*buf) != sizeof(fpregs));
 171        n = copy_from_user(fpregs, buf, sizeof(fpregs));
 172        if (n > 0)
 173                return -EFAULT;
 174
 175        return restore_fp_registers(userspace_pid[cpu], fpregs);
 176}
 177
 178long subarch_ptrace(struct task_struct *child, long request, long addr,
 179                    long data)
 180{
 181        int ret = -EIO;
 182
 183        switch (request) {
 184        case PTRACE_GETFPXREGS: /* Get the child FPU state. */
 185                ret = get_fpregs((struct user_i387_struct __user *) data,
 186                                 child);
 187                break;
 188        case PTRACE_SETFPXREGS: /* Set the child FPU state. */
 189                ret = set_fpregs((struct user_i387_struct __user *) data,
 190                                 child);
 191                break;
 192        }
 193
 194        return ret;
 195}
 196