204 lines
4.3 KiB
C
204 lines
4.3 KiB
C
/*
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* Copyright (C) 2000-2003, Axis Communications AB.
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*/
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/errno.h>
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#include <linux/ptrace.h>
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#include <linux/user.h>
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#include <linux/signal.h>
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#include <linux/security.h>
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#include <asm/uaccess.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include <asm/system.h>
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#include <asm/processor.h>
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/*
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* Determines which bits in DCCR the user has access to.
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* 1 = access, 0 = no access.
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*/
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#define DCCR_MASK 0x0000001f /* XNZVC */
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/*
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* Get contents of register REGNO in task TASK.
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*/
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inline long get_reg(struct task_struct *task, unsigned int regno)
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{
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/* USP is a special case, it's not in the pt_regs struct but
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* in the tasks thread struct
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*/
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if (regno == PT_USP)
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return task->thread.usp;
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else if (regno < PT_MAX)
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return ((unsigned long *)task_pt_regs(task))[regno];
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else
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return 0;
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}
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/*
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* Write contents of register REGNO in task TASK.
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*/
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inline int put_reg(struct task_struct *task, unsigned int regno,
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unsigned long data)
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{
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if (regno == PT_USP)
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task->thread.usp = data;
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else if (regno < PT_MAX)
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((unsigned long *)task_pt_regs(task))[regno] = data;
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else
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return -1;
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return 0;
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}
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/*
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* Called by kernel/ptrace.c when detaching.
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*
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* Make sure the single step bit is not set.
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*/
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void
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ptrace_disable(struct task_struct *child)
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{
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/* Todo - pending singlesteps? */
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clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
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}
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/*
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* Note that this implementation of ptrace behaves differently from vanilla
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* ptrace. Contrary to what the man page says, in the PTRACE_PEEKTEXT,
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* PTRACE_PEEKDATA, and PTRACE_PEEKUSER requests the data variable is not
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* ignored. Instead, the data variable is expected to point at a location
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* (in user space) where the result of the ptrace call is written (instead of
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* being returned).
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*/
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long arch_ptrace(struct task_struct *child, long request,
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unsigned long addr, unsigned long data)
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{
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int ret;
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unsigned int regno = addr >> 2;
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unsigned long __user *datap = (unsigned long __user *)data;
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switch (request) {
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/* Read word at location address. */
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case PTRACE_PEEKTEXT:
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case PTRACE_PEEKDATA:
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ret = generic_ptrace_peekdata(child, addr, data);
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break;
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/* Read the word at location address in the USER area. */
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case PTRACE_PEEKUSR: {
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unsigned long tmp;
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ret = -EIO;
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if ((addr & 3) || regno > PT_MAX)
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break;
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tmp = get_reg(child, regno);
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ret = put_user(tmp, datap);
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break;
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}
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/* Write the word at location address. */
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case PTRACE_POKETEXT:
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case PTRACE_POKEDATA:
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ret = generic_ptrace_pokedata(child, addr, data);
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break;
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/* Write the word at location address in the USER area. */
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case PTRACE_POKEUSR:
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ret = -EIO;
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if ((addr & 3) || regno > PT_MAX)
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break;
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if (regno == PT_DCCR) {
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/* don't allow the tracing process to change stuff like
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* interrupt enable, kernel/user bit, dma enables etc.
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*/
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data &= DCCR_MASK;
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data |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
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}
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if (put_reg(child, regno, data))
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break;
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ret = 0;
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break;
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/* Get all GP registers from the child. */
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case PTRACE_GETREGS: {
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int i;
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unsigned long tmp;
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ret = 0;
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for (i = 0; i <= PT_MAX; i++) {
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tmp = get_reg(child, i);
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if (put_user(tmp, datap)) {
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ret = -EFAULT;
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break;
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}
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datap++;
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}
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break;
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}
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/* Set all GP registers in the child. */
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case PTRACE_SETREGS: {
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int i;
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unsigned long tmp;
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ret = 0;
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for (i = 0; i <= PT_MAX; i++) {
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if (get_user(tmp, datap)) {
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ret = -EFAULT;
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break;
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}
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if (i == PT_DCCR) {
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tmp &= DCCR_MASK;
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tmp |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
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}
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put_reg(child, i, tmp);
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datap++;
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}
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break;
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}
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default:
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ret = ptrace_request(child, request, addr, data);
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break;
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}
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return ret;
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}
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void do_syscall_trace(void)
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{
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if (!test_thread_flag(TIF_SYSCALL_TRACE))
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return;
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if (!(current->ptrace & PT_PTRACED))
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return;
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/* the 0x80 provides a way for the tracing parent to distinguish
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between a syscall stop and SIGTRAP delivery */
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ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
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? 0x80 : 0));
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/*
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* This isn't the same as continuing with a signal, but it will do for
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* normal use.
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*/
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if (current->exit_code) {
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send_sig(current->exit_code, current, 1);
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current->exit_code = 0;
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}
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}
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