ptrace.c

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/*
 *  Port on Texas Instruments TMS320C6x architecture
 *
 *  Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
 *  Author: Aurelien Jacquiot ([email protected])
 *
 *  Updated for 2.6.34: Mark Salter <[email protected]>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 */
#include <linux/ptrace.h>
#include <linux/tracehook.h>
#include <linux/regset.h>
#include <linux/elf.h>

#include <asm/cacheflush.h>

#define PT_REG_SIZE   (sizeof(struct pt_regs))

/*
 * Called by kernel/ptrace.c when detaching.
 */
void ptrace_disable(struct task_struct *child)
{
    /* nothing to do */
}

/*
 * Get a register number from live pt_regs for the specified task.
 */
static inline long get_reg(struct task_struct *task, int regno)
{
    long *addr = (long *)task_pt_regs(task);

    if (regno == PT_TSR || regno == PT_CSR)
        return 0;

    return addr[regno];
}

/*
 * Write contents of register REGNO in task TASK.
 */
static inline int put_reg(struct task_struct *task,
              int regno,
              unsigned long data)
{
    unsigned long *addr = (unsigned long *)task_pt_regs(task);

    if (regno != PT_TSR && regno != PT_CSR)
        addr[regno] = data;

    return 0;
}

/* regset get/set implementations */

static int gpr_get(struct task_struct *target,
           const struct user_regset *regset,
           unsigned int pos, unsigned int count,
           void *kbuf, void __user *ubuf)
{
    struct pt_regs *regs = task_pt_regs(target);

    return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
                   regs,
                   0, sizeof(*regs));
}

static int gpr_set(struct task_struct *target,
           const struct user_regset *regset,
           unsigned int pos, unsigned int count,
           const void *kbuf, const void __user *ubuf)
{
    int ret;
    struct pt_regs *regs = task_pt_regs(target);

    /* Don't copyin TSR or CSR */
    ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                 &regs,
                 0, PT_TSR * sizeof(long));
    if (ret)
        return ret;

    ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
                    PT_TSR * sizeof(long),
                    (PT_TSR + 1) * sizeof(long));
    if (ret)
        return ret;

    ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                 &regs,
                 (PT_TSR + 1) * sizeof(long),
                 PT_CSR * sizeof(long));
    if (ret)
        return ret;

    ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
                    PT_CSR * sizeof(long),
                    (PT_CSR + 1) * sizeof(long));
    if (ret)
        return ret;

    ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                 &regs,
                 (PT_CSR + 1) * sizeof(long), -1);
    return ret;
}

enum c6x_regset {
    REGSET_GPR,
};

static const struct user_regset c6x_regsets[] = {
    [REGSET_GPR] = {
        .core_note_type = NT_PRSTATUS,
        .n = ELF_NGREG,
        .size = sizeof(u32),
        .align = sizeof(u32),
        .get = gpr_get,
        .set = gpr_set
    },
};

static const struct user_regset_view user_c6x_native_view = {
    .name       = "tic6x",
    .e_machine  = EM_TI_C6000,
    .regsets    = c6x_regsets,
    .n      = ARRAY_SIZE(c6x_regsets),
};

const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
    return &user_c6x_native_view;
}

/*
 * Perform ptrace request
 */
long arch_ptrace(struct task_struct *child, long request,
         unsigned long addr, unsigned long data)
{
    int ret = 0;

    switch (request) {
        /*
         * write the word at location addr.
         */
    case PTRACE_POKETEXT:
        ret = generic_ptrace_pokedata(child, addr, data);
        if (ret == 0 && request == PTRACE_POKETEXT)
            flush_icache_range(addr, addr + 4);
        break;
    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(struct pt_regs *regs)
{
    if (tracehook_report_syscall_entry(regs))
        /* 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
         * regs->orig_a4
         */
        return ULONG_MAX;

    return regs->b0;
}

/*
 * handle tracing of system call exit
 */
asmlinkage void syscall_trace_exit(struct pt_regs *regs)
{
    tracehook_report_syscall_exit(regs, 0);
}