ptrace.c

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/* ptrace.c: FRV specific parts of process tracing
 *
 * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 * - Derived from arch/m68k/kernel/ptrace.c
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/security.h>
#include <linux/signal.h>
#include <linux/regset.h>
#include <linux/elf.h>
#include <linux/tracehook.h>

#include <asm/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/unistd.h>

/*
 * does not yet catch signals sent when the child dies.
 * in exit.c or in signal.c.
 */

/*
 * retrieve the contents of FRV userspace general registers
 */
static int genregs_get(struct task_struct *target,
               const struct user_regset *regset,
               unsigned int pos, unsigned int count,
               void *kbuf, void __user *ubuf)
{
    const struct user_int_regs *iregs = &target->thread.user->i;
    int ret;

    ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
                  iregs, 0, sizeof(*iregs));
    if (ret < 0)
        return ret;

    return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
                    sizeof(*iregs), -1);
}

/*
 * update the contents of the FRV userspace general registers
 */
static int genregs_set(struct task_struct *target,
               const struct user_regset *regset,
               unsigned int pos, unsigned int count,
               const void *kbuf, const void __user *ubuf)
{
    struct user_int_regs *iregs = &target->thread.user->i;
    unsigned int offs_gr0, offs_gr1;
    int ret;

    /* not allowed to set PSR or __status */
    if (pos < offsetof(struct user_int_regs, psr) + sizeof(long) &&
        pos + count > offsetof(struct user_int_regs, psr))
        return -EIO;

    if (pos < offsetof(struct user_int_regs, __status) + sizeof(long) &&
        pos + count > offsetof(struct user_int_regs, __status))
        return -EIO;

    /* set the control regs */
    offs_gr0 = offsetof(struct user_int_regs, gr[0]);
    offs_gr1 = offsetof(struct user_int_regs, gr[1]);
    ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                 iregs, 0, offs_gr0);
    if (ret < 0)
        return ret;

    /* skip GR0/TBR */
    ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
                    offs_gr0, offs_gr1);
    if (ret < 0)
        return ret;

    /* set the general regs */
    ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                 &iregs->gr[1], offs_gr1, sizeof(*iregs));
    if (ret < 0)
        return ret;

    return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
                    sizeof(*iregs), -1);
}

/*
 * retrieve the contents of FRV userspace FP/Media registers
 */
static int fpmregs_get(struct task_struct *target,
               const struct user_regset *regset,
               unsigned int pos, unsigned int count,
               void *kbuf, void __user *ubuf)
{
    const struct user_fpmedia_regs *fpregs = &target->thread.user->f;
    int ret;

    ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
                  fpregs, 0, sizeof(*fpregs));
    if (ret < 0)
        return ret;

    return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
                    sizeof(*fpregs), -1);
}

/*
 * update the contents of the FRV userspace FP/Media registers
 */
static int fpmregs_set(struct task_struct *target,
               const struct user_regset *regset,
               unsigned int pos, unsigned int count,
               const void *kbuf, const void __user *ubuf)
{
    struct user_fpmedia_regs *fpregs = &target->thread.user->f;
    int ret;

    ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                 fpregs, 0, sizeof(*fpregs));
    if (ret < 0)
        return ret;

    return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
                    sizeof(*fpregs), -1);
}

/*
 * determine if the FP/Media registers have actually been used
 */
static int fpmregs_active(struct task_struct *target,
              const struct user_regset *regset)
{
    return tsk_used_math(target) ? regset->n : 0;
}

/*
 * Define the register sets available on the FRV under Linux
 */
enum frv_regset {
    REGSET_GENERAL,
    REGSET_FPMEDIA,
};

static const struct user_regset frv_regsets[] = {
    /*
     * General register format is:
     *  PSR, ISR, CCR, CCCR, LR, LCR, PC, (STATUS), SYSCALLNO, ORIG_G8
     *  GNER0-1, IACC0, TBR, GR1-63
     */
    [REGSET_GENERAL] = {
        .core_note_type = NT_PRSTATUS,
        .n      = ELF_NGREG,
        .size       = sizeof(long),
        .align      = sizeof(long),
        .get        = genregs_get,
        .set        = genregs_set,
    },
    /*
     * FPU/Media register format is:
     *  FR0-63, FNER0-1, MSR0-1, ACC0-7, ACCG0-8, FSR
     */
    [REGSET_FPMEDIA] = {
        .core_note_type = NT_PRFPREG,
        .n      = sizeof(struct user_fpmedia_regs) / sizeof(long),
        .size       = sizeof(long),
        .align      = sizeof(long),
        .get        = fpmregs_get,
        .set        = fpmregs_set,
        .active     = fpmregs_active,
    },
};

static const struct user_regset_view user_frv_native_view = {
    .name       = "frv",
    .e_machine  = EM_FRV,
    .regsets    = frv_regsets,
    .n      = ARRAY_SIZE(frv_regsets),
};

const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
    return &user_frv_native_view;
}

/*
 * Get contents of register REGNO in task TASK.
 */
static inline long get_reg(struct task_struct *task, int regno)
{
    struct user_context *user = task->thread.user;

    if (regno < 0 || regno >= PT__END)
        return 0;

    return ((unsigned long *) user)[regno];
}

/*
 * Write contents of register REGNO in task TASK.
 */
static inline int put_reg(struct task_struct *task, int regno,
              unsigned long data)
{
    struct user_context *user = task->thread.user;

    if (regno < 0 || regno >= PT__END)
        return -EIO;

    switch (regno) {
    case PT_GR(0):
        return 0;
    case PT_PSR:
    case PT__STATUS:
        return -EIO;
    default:
        ((unsigned long *) user)[regno] = data;
        return 0;
    }
}

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Control h/w single stepping
 */
void user_enable_single_step(struct task_struct *child)
{
    child->thread.frame0->__status |= REG__STATUS_STEP;
}

void user_disable_single_step(struct task_struct *child)
{
    child->thread.frame0->__status &= ~REG__STATUS_STEP;
}

void ptrace_disable(struct task_struct *child)
{
    user_disable_single_step(child);
}

long arch_ptrace(struct task_struct *child, long request,
         unsigned long addr, unsigned long data)
{
    unsigned long tmp;
    int ret;
    int regno = addr >> 2;
    unsigned long __user *datap = (unsigned long __user *) data;

    switch (request) {
        /* read the word at location addr in the USER area. */
    case PTRACE_PEEKUSR: {
        tmp = 0;
        ret = -EIO;
        if (addr & 3)
            break;

        ret = 0;
        switch (regno) {
        case 0 ... PT__END - 1:
            tmp = get_reg(child, regno);
            break;

        case PT__END + 0:
            tmp = child->mm->end_code - child->mm->start_code;
            break;

        case PT__END + 1:
            tmp = child->mm->end_data - child->mm->start_data;
            break;

        case PT__END + 2:
            tmp = child->mm->start_stack - child->mm->start_brk;
            break;

        case PT__END + 3:
            tmp = child->mm->start_code;
            break;

        case PT__END + 4:
            tmp = child->mm->start_stack;
            break;

        default:
            ret = -EIO;
            break;
        }

        if (ret == 0)
            ret = put_user(tmp, datap);
        break;
    }

    case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
        ret = -EIO;
        if (addr & 3)
            break;

        switch (regno) {
        case 0 ... PT__END - 1:
            ret = put_reg(child, regno, data);
            break;
        }
        break;

    case PTRACE_GETREGS:    /* Get all integer regs from the child. */
        return copy_regset_to_user(child, &user_frv_native_view,
                       REGSET_GENERAL,
                       0, sizeof(child->thread.user->i),
                       datap);

    case PTRACE_SETREGS:    /* Set all integer regs in the child. */
        return copy_regset_from_user(child, &user_frv_native_view,
                         REGSET_GENERAL,
                         0, sizeof(child->thread.user->i),
                         datap);

    case PTRACE_GETFPREGS:  /* Get the child FP/Media state. */
        return copy_regset_to_user(child, &user_frv_native_view,
                       REGSET_FPMEDIA,
                       0, sizeof(child->thread.user->f),
                       datap);

    case PTRACE_SETFPREGS:  /* Set the child FP/Media state. */
        return copy_regset_from_user(child, &user_frv_native_view,
                         REGSET_FPMEDIA,
                         0, sizeof(child->thread.user->f),
                         datap);

    default:
        ret = ptrace_request(child, request, addr, data);
        break;
    }
    return ret;
}

/*
 * handle tracing of system call entry
 * - return the revised system call number or ULONG_MAX to cause ENOSYS
 */
asmlinkage unsigned long syscall_trace_entry(void)
{
    __frame->__status |= REG__STATUS_SYSC_ENTRY;
    if (tracehook_report_syscall_entry(__frame)) {
        /* tracing decided this syscall should not happen, so
         * We'll return a bogus call number to get an ENOSYS
         * error, but leave the original number in
         * __frame->syscallno
         */
        return ULONG_MAX;
    }

    return __frame->syscallno;
}

/*
 * handle tracing of system call exit
 */
asmlinkage void syscall_trace_exit(void)
{
    __frame->__status |= REG__STATUS_SYSC_EXIT;
    tracehook_report_syscall_exit(__frame, 0);
}