/*
* `ptrace' system call
*
* Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
* Copyright (C) 2007-2009 PetaLogix
* Copyright (C) 2004-2007 John Williams <john.williams@petalogix.com>
*
* derived from arch/v850/kernel/ptrace.c
*
* Copyright (C) 2002,03 NEC Electronics Corporation
* Copyright (C) 2002,03 Miles Bader <miles@gnu.org>
*
* Derived from arch/mips/kernel/ptrace.c:
*
* Copyright (C) 1992 Ross Biro
* Copyright (C) Linus Torvalds
* Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle
* Copyright (C) 1996 David S. Miller
* Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
* Copyright (C) 1999 MIPS Technologies, Inc.
*
* This file is subject to the terms and conditions of the GNU General
* Public License. See the file COPYING in the main directory of this
* archive for more details.
*/
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/signal.h>
#include <linux/elf.h>
#include <linux/audit.h>
#include <linux/seccomp.h>
#include <linux/tracehook.h>
#include <linux/errno.h>
#include <asm/processor.h>
#include <linux/uaccess.h>
#include <asm/asm-offsets.h>
#include <asm/cacheflush.h>
#include <asm/syscall.h>
#include <linux/io.h>
/* Returns the address where the register at REG_OFFS in P is stashed away. */
static microblaze_reg_t *reg_save_addr(unsigned reg_offs,
struct task_struct *t)
{
struct pt_regs *regs;
/*
* Three basic cases:
*
* (1) A register normally saved before calling the scheduler, is
* available in the kernel entry pt_regs structure at the top
* of the kernel stack. The kernel trap/irq exit path takes
* care to save/restore almost all registers for ptrace'd
* processes.
*
* (2) A call-clobbered register, where the process P entered the
* kernel via [syscall] trap, is not stored anywhere; that's
* OK, because such registers are not expected to be preserved
* when the trap returns anyway (so we don't actually bother to
* test for this case).
*
* (3) A few registers not used at all by the kernel, and so
* normally never saved except by context-switches, are in the
* context switch state.
*/
/* Register saved during kernel entry (or not available). */
regs = task_pt_regs(t);
return (microblaze_reg_t *)((char *)regs + reg_offs);
}
long arch_ptrace(struct task_struct *child, long request,
unsigned long addr, unsigned long data)
{
int rval;
unsigned long val = 0;
switch (request) {
/* Read/write the word at location ADDR in the registers. */
case PTRACE_PEEKUSR:
case PTRACE_POKEUSR:
pr_debug("PEEKUSR/POKEUSR : 0x%08lx\n", addr);
rval = 0;
if (addr >= PT_SIZE && request == PTRACE_PEEKUSR) {
/*
* Special requests that don't actually correspond
* to offsets in struct pt_regs.
*/
if (addr == PT_TEXT_ADDR) {
val = child->mm->start_code;
} else if (addr == PT_DATA_ADDR) {
val = child->mm->start_data;
} else if (addr == PT_TEXT_LEN) {
val = child->mm->end_code
- child->mm->start_code;
} else {
rval = -EIO;
}
} else if (addr < PT_SIZE && (addr & 0x3) == 0) {
microblaze_reg_t *reg_addr = reg_save_addr(addr, child);
if (request == PTRACE_PEEKUSR)
val = *reg_addr;
else {
#if 1
*reg_addr = data;
#else
/* MS potential problem on WB system
* Be aware that reg_addr is virtual address
* virt_to_phys conversion is necessary.
* This could be sensible solution.
*/
u32 paddr = virt_to_phys((u32)reg_addr);
invalidate_icache_range(paddr, paddr + 4);
*reg_addr = data;
flush_dcache_range(paddr, paddr + 4);
#endif
}
} else
rval = -EIO;
if (rval == 0 && request == PTRACE_PEEKUSR)
rval = put_user(val, (unsigned long __user *)data);
break;
default:
rval = ptrace_request(child, request, addr, data);
}
return rval;
}
asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
{
long ret = 0;
secure_computing_strict(regs->r12);
if (test_thread_flag(TIF_SYSCALL_TRACE) &&
tracehook_report_syscall_entry(regs))
/*
* Tracing decided this syscall should not happen.
* We'll return a bogus call number to get an ENOSYS
* error, but leave the original number in regs->regs[0].
*/
ret = -1L;
audit_syscall_entry(EM_MICROBLAZE, regs->r12, regs->r5, regs->r6,
regs->r7, regs->r8);
return ret ?: regs->r12;
}
asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
{
int step;
audit_syscall_exit(regs);
step = test_thread_flag(TIF_SINGLESTEP);
if (step || test_thread_flag(TIF_SYSCALL_TRACE))
tracehook_report_syscall_exit(regs, step);
}
void ptrace_disable(struct task_struct *child)
{
/* nothing to do */
}
