362 lines
8.7 KiB
C
362 lines
8.7 KiB
C
/*
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* Copyright (C) 2004-2006 Atmel Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#undef DEBUG
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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/ptrace.h>
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#include <linux/errno.h>
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#include <linux/user.h>
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#include <linux/security.h>
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#include <linux/unistd.h>
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#include <linux/notifier.h>
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#include <asm/traps.h>
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#include <asm/uaccess.h>
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#include <asm/ocd.h>
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#include <asm/mmu_context.h>
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#include <linux/kdebug.h>
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static struct pt_regs *get_user_regs(struct task_struct *tsk)
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{
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return (struct pt_regs *)((unsigned long)task_stack_page(tsk) +
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THREAD_SIZE - sizeof(struct pt_regs));
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}
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static void ptrace_single_step(struct task_struct *tsk)
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{
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pr_debug("ptrace_single_step: pid=%u, SR=0x%08lx\n",
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tsk->pid, tsk->thread.cpu_context.sr);
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if (!(tsk->thread.cpu_context.sr & SR_D)) {
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/*
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* Set a breakpoint at the current pc to force the
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* process into debug mode. The syscall/exception
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* exit code will set a breakpoint at the return
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* address when this flag is set.
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*/
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pr_debug("ptrace_single_step: Setting TIF_BREAKPOINT\n");
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set_tsk_thread_flag(tsk, TIF_BREAKPOINT);
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}
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/* The monitor code will do the actual step for us */
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set_tsk_thread_flag(tsk, TIF_SINGLE_STEP);
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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 any single step bits, etc. are not set
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*/
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void ptrace_disable(struct task_struct *child)
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{
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clear_tsk_thread_flag(child, TIF_SINGLE_STEP);
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}
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/*
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* Handle hitting a breakpoint
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*/
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static void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
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{
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siginfo_t info;
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info.si_signo = SIGTRAP;
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info.si_errno = 0;
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info.si_code = TRAP_BRKPT;
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info.si_addr = (void __user *)instruction_pointer(regs);
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pr_debug("ptrace_break: Sending SIGTRAP to PID %u (pc = 0x%p)\n",
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tsk->pid, info.si_addr);
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force_sig_info(SIGTRAP, &info, tsk);
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}
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/*
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* Read the word at offset "offset" into the task's "struct user". We
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* actually access the pt_regs struct stored on the kernel stack.
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*/
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static int ptrace_read_user(struct task_struct *tsk, unsigned long offset,
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unsigned long __user *data)
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{
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unsigned long *regs;
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unsigned long value;
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pr_debug("ptrace_read_user(%p, %#lx, %p)\n",
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tsk, offset, data);
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if (offset & 3 || offset >= sizeof(struct user)) {
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printk("ptrace_read_user: invalid offset 0x%08lx\n", offset);
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return -EIO;
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}
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regs = (unsigned long *)get_user_regs(tsk);
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value = 0;
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if (offset < sizeof(struct pt_regs))
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value = regs[offset / sizeof(regs[0])];
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return put_user(value, data);
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}
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/*
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* Write the word "value" to offset "offset" into the task's "struct
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* user". We actually access the pt_regs struct stored on the kernel
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* stack.
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*/
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static int ptrace_write_user(struct task_struct *tsk, unsigned long offset,
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unsigned long value)
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{
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unsigned long *regs;
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if (offset & 3 || offset >= sizeof(struct user)) {
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printk("ptrace_write_user: invalid offset 0x%08lx\n", offset);
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return -EIO;
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}
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if (offset >= sizeof(struct pt_regs))
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return 0;
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regs = (unsigned long *)get_user_regs(tsk);
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regs[offset / sizeof(regs[0])] = value;
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return 0;
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}
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static int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
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{
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struct pt_regs *regs = get_user_regs(tsk);
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return copy_to_user(uregs, regs, sizeof(*regs)) ? -EFAULT : 0;
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}
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static int ptrace_setregs(struct task_struct *tsk, const void __user *uregs)
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{
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struct pt_regs newregs;
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int ret;
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ret = -EFAULT;
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if (copy_from_user(&newregs, uregs, sizeof(newregs)) == 0) {
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struct pt_regs *regs = get_user_regs(tsk);
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ret = -EINVAL;
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if (valid_user_regs(&newregs)) {
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*regs = newregs;
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ret = 0;
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}
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}
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return ret;
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}
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long arch_ptrace(struct task_struct *child, long request, long addr, long data)
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{
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int ret;
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pr_debug("arch_ptrace(%ld, %d, %#lx, %#lx)\n",
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request, child->pid, addr, data);
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pr_debug("ptrace: Enabling monitor mode...\n");
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__mtdr(DBGREG_DC, __mfdr(DBGREG_DC) | DC_MM | DC_DBE);
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switch (request) {
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/* Read the word at location addr in the child process */
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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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case PTRACE_PEEKUSR:
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ret = ptrace_read_user(child, addr,
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(unsigned long __user *)data);
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break;
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/* Write the word in data at location addr */
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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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case PTRACE_POKEUSR:
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ret = ptrace_write_user(child, addr, data);
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break;
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/* continue and stop at next (return from) syscall */
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case PTRACE_SYSCALL:
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/* restart after signal */
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case PTRACE_CONT:
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ret = -EIO;
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if (!valid_signal(data))
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break;
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if (request == PTRACE_SYSCALL)
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set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
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else
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clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
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child->exit_code = data;
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/* XXX: Are we sure no breakpoints are active here? */
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wake_up_process(child);
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ret = 0;
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break;
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/*
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* Make the child exit. Best I can do is send it a
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* SIGKILL. Perhaps it should be put in the status that it
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* wants to exit.
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*/
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case PTRACE_KILL:
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ret = 0;
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if (child->exit_state == EXIT_ZOMBIE)
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break;
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child->exit_code = SIGKILL;
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wake_up_process(child);
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break;
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/*
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* execute single instruction.
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*/
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case PTRACE_SINGLESTEP:
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ret = -EIO;
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if (!valid_signal(data))
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break;
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clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
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ptrace_single_step(child);
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child->exit_code = data;
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wake_up_process(child);
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ret = 0;
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break;
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/* Detach a process that was attached */
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case PTRACE_DETACH:
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ret = ptrace_detach(child, data);
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break;
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case PTRACE_GETREGS:
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ret = ptrace_getregs(child, (void __user *)data);
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break;
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case PTRACE_SETREGS:
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ret = ptrace_setregs(child, (const void __user *)data);
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break;
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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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pr_debug("sys_ptrace returning %d (DC = 0x%08lx)\n", ret, __mfdr(DBGREG_DC));
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return ret;
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}
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asmlinkage void syscall_trace(void)
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{
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pr_debug("syscall_trace called\n");
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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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pr_debug("syscall_trace: notifying parent\n");
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/* The 0x80 provides a way for the tracing parent to
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* distinguish 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
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* will do for normal use. strace only continues with a
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* signal if the stopping signal is not SIGTRAP. -brl
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*/
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if (current->exit_code) {
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pr_debug("syscall_trace: sending signal %d to PID %u\n",
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current->exit_code, current->pid);
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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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asmlinkage void do_debug_priv(struct pt_regs *regs)
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{
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unsigned long dc, ds;
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unsigned long die_val;
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ds = __mfdr(DBGREG_DS);
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pr_debug("do_debug_priv: pc = %08lx, ds = %08lx\n", regs->pc, ds);
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if (ds & DS_SSS)
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die_val = DIE_SSTEP;
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else
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die_val = DIE_BREAKPOINT;
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if (notify_die(die_val, "ptrace", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
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return;
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if (likely(ds & DS_SSS)) {
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extern void itlb_miss(void);
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extern void tlb_miss_common(void);
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struct thread_info *ti;
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dc = __mfdr(DBGREG_DC);
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dc &= ~DC_SS;
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__mtdr(DBGREG_DC, dc);
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ti = current_thread_info();
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set_ti_thread_flag(ti, TIF_BREAKPOINT);
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/* The TLB miss handlers don't check thread flags */
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if ((regs->pc >= (unsigned long)&itlb_miss)
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&& (regs->pc <= (unsigned long)&tlb_miss_common)) {
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__mtdr(DBGREG_BWA2A, sysreg_read(RAR_EX));
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__mtdr(DBGREG_BWC2A, 0x40000001 | (get_asid() << 1));
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}
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/*
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* If we're running in supervisor mode, the breakpoint
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* will take us where we want directly, no need to
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* single step.
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*/
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if ((regs->sr & MODE_MASK) != MODE_SUPERVISOR)
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set_ti_thread_flag(ti, TIF_SINGLE_STEP);
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} else {
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panic("Unable to handle debug trap at pc = %08lx\n",
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regs->pc);
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}
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}
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/*
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* Handle breakpoints, single steps and other debuggy things. To keep
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* things simple initially, we run with interrupts and exceptions
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* disabled all the time.
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*/
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asmlinkage void do_debug(struct pt_regs *regs)
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{
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unsigned long dc, ds;
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ds = __mfdr(DBGREG_DS);
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pr_debug("do_debug: pc = %08lx, ds = %08lx\n", regs->pc, ds);
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if (test_thread_flag(TIF_BREAKPOINT)) {
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pr_debug("TIF_BREAKPOINT set\n");
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/* We're taking care of it */
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clear_thread_flag(TIF_BREAKPOINT);
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__mtdr(DBGREG_BWC2A, 0);
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}
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if (test_thread_flag(TIF_SINGLE_STEP)) {
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pr_debug("TIF_SINGLE_STEP set, ds = 0x%08lx\n", ds);
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if (ds & DS_SSS) {
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dc = __mfdr(DBGREG_DC);
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dc &= ~DC_SS;
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__mtdr(DBGREG_DC, dc);
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clear_thread_flag(TIF_SINGLE_STEP);
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ptrace_break(current, regs);
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}
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} else {
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/* regular breakpoint */
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ptrace_break(current, regs);
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}
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}
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