/*
* 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.
*
* arch/sh64/kernel/ptrace.c
*
* Copyright (C) 2000, 2001 Paolo Alberelli
* Copyright (C) 2003 Paul Mundt
*
* Started from SH3/4 version:
* SuperH version: Copyright (C) 1999, 2000 Kaz Kojima & Niibe Yutaka
*
* Original x86 implementation:
* By Ross Biro 1/23/92
* edited by Linus Torvalds
*
*/
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/rwsem.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/signal.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>
#include <asm/mmu_context.h>
/* This mask defines the bits of the SR which the user is not allowed to
change, which are everything except S, Q, M, PR, SZ, FR. */
#define SR_MASK (0xffff8cfd)
/*
* does not yet catch signals sent when the child dies.
* in exit.c or in signal.c.
*/
/*
* This routine will get a word from the user area in the process kernel stack.
*/
static inline int get_stack_long(struct task_struct *task, int offset)
{
unsigned char *stack;
stack = (unsigned char *)(task->thread.uregs);
stack += offset;
return (*((int *)stack));
}
static inline unsigned long
get_fpu_long(struct task_struct *task, unsigned long addr)
{
unsigned long tmp;
struct pt_regs *regs;
regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
if (!tsk_used_math(task)) {
if (addr == offsetof(struct user_fpu_struct, fpscr)) {
tmp = FPSCR_INIT;
} else {
tmp = 0xffffffffUL; /* matches initial value in fpu.c */
}
return tmp;
}
if (last_task_used_math == task) {
grab_fpu();
fpsave(&task->thread.fpu.hard);
release_fpu();
last_task_used_math = 0;
regs->sr |= SR_FD;
}
tmp = ((long *)&task->thread.fpu)[addr / sizeof(unsigned long)];
return tmp;
}
/*
* This routine will put a word into the user area in the process kernel stack.
*/
static inline int put_stack_long(struct task_struct *task, int offset,
unsigned long data)
{
unsigned char *stack;
stack = (unsigned char *)(task->thread.uregs);
stack += offset;
*(unsigned long *) stack = data;
return 0;
}
static inline int
put_fpu_long(struct task_struct *task, unsigned long addr, unsigned long data)
{
struct pt_regs *regs;
regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
if (!tsk_used_math(task)) {
fpinit(&task->thread.fpu.hard);
set_stopped_child_used_math(task);
} else if (last_task_used_math == task) {
grab_fpu();
fpsave(&task->thread.fpu.hard);
release_fpu();
last_task_used_math = 0;
regs->sr |= SR_FD;
}
((long *)&task->thread.fpu)[addr / sizeof(unsigned long)] = data;
return 0;
}
asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
{
struct task_struct *child;
extern void poke_real_address_q(unsigned long long addr, unsigned long long data);
#define WPC_DBRMODE 0x0d104008
static int first_call = 1;
int ret;
lock_kernel();
if (first_call) {
/* Set WPC.DBRMODE to 0. This makes all debug events get
* delivered through RESVEC, i.e. into the handlers in entry.S.
* (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
* would normally be left set to 1, which makes debug events get
* delivered through DBRVEC, i.e. into the remote gdb's
* handlers. This prevents ptrace getting them, and confuses
* the remote gdb.) */
printk("DBRMODE set to 0 to permit native debugging\n");
poke_real_address_q(WPC_DBRMODE, 0);
first_call = 0;
}
ret = -EPERM;
if (request == PTRACE_TRACEME) {
/* are we already being traced? */
if (current->ptrace & PT_PTRACED)
goto out;
/* set the ptrace bit in the process flags. */
current->ptrace |= PT_PTRACED;
ret = 0;
goto out;
}
ret = -ESRCH;
read_lock(&tasklist_lock);
child = find_task_by_pid(pid);
if (child)
get_task_struct(child);
read_unlock(&tasklist_lock);
if (!child)
goto out;
ret = -EPERM;
if (pid == 1) /* you may not mess with init */
goto out_tsk;
if (request == PTRACE_ATTACH) {
ret = ptrace_attach(child);
goto out_tsk;
}
ret = ptrace_check_attach(child, request == PTRACE_KILL);
if (ret < 0)
goto out_tsk;
switch (request) {
/* when I and D space are separate, these will need to be fixed. */
case PTRACE_PEEKTEXT: /* read word at location addr. */
case PTRACE_PEEKDATA: {
unsigned long tmp;
int copied;
copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
ret = -EIO;
if (copied != sizeof(tmp))
break;
ret = put_user(tmp,(unsigned long *) data);
break;
}
/* read the word at location addr in the USER area. */
case PTRACE_PEEKUSR: {
unsigned long tmp;
ret = -EIO;
if ((addr & 3) || addr < 0)
break;
if (addr < sizeof(struct pt_regs))
tmp = get_stack_long(child, addr);
else if ((addr >= offsetof(struct user, fpu)) &&
(addr < offsetof(struct user, u_fpvalid))) {
tmp = get_fpu_long(child, addr - offsetof(struct user, fpu));
} else if (addr == offsetof(struct user, u_fpvalid)) {
tmp = !!tsk_used_math(child);
} else {
break;
}
ret = put_user(tmp, (unsigned long *)data);
break;
}
/* when I and D space are separate, this will have to be fixed. */
case PTRACE_POKETEXT: /* write the word at location addr. */
case PTRACE_POKEDATA:
ret = 0;
if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
break;
ret = -EIO;
break;
case PTRACE_POKEUSR:
/* write the word at location addr in the USER area. We must
disallow any changes to certain SR bits or u_fpvalid, since
this could crash the kernel or result in a security
loophole. */
ret = -EIO;
if ((addr & 3) || addr < 0)
break;
if (addr < sizeof(struct pt_regs)) {
/* Ignore change of top 32 bits of SR */
if (addr == offsetof (struct pt_regs, sr)+4)
{
ret = 0;
break;
}
/* If lower 32 bits of SR, ignore non-user bits */
if (addr == offsetof (struct pt_regs, sr))
{
long cursr = get_stack_long(child, addr);
data &= ~(SR_MASK);
data |= (cursr & SR_MASK);
}
ret = put_stack_long(child, addr, data);
}
else if ((addr >= offsetof(struct user, fpu)) &&
(addr < offsetof(struct user, u_fpvalid))) {
ret = put_fpu_long(child, addr - offsetof(struct user, fpu), data);
}
break;
case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
case PTRACE_CONT: { /* restart after signal. */
ret = -EIO;
if (!valid_signal(data))
break;
if (request == PTRACE_SYSCALL)
set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
else
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
child->exit_code = data;
wake_up_process(child);
ret = 0;
break;
}
/*
* make the child exit. Best I can do is send it a sigkill.
* perhaps it should be put in the status that it wants to
* exit.
*/
case PTRACE_KILL: {
ret = 0;
if (child->exit_state == EXIT_ZOMBIE) /* already dead */
break;
child->exit_code = SIGKILL;
wake_up_process(child);
break;
}
case PTRACE_SINGLESTEP: { /* set the trap flag. */
struct pt_regs *regs;
ret = -EIO;
if (!valid_signal(data))
break;
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
if ((child->ptrace & PT_DTRACE) == 0) {
/* Spurious delayed TF traps may occur */
child->ptrace |= PT_DTRACE;
}
regs = child->thread.uregs;
regs->sr |= SR_SSTEP; /* auto-resetting upon exception */
child->exit_code = data;
/* give it a chance to run. */
wake_up_process(child);
ret = 0;
break;
}
case PTRACE_DETACH: /* detach a process that was attached. */
ret = ptrace_detach(child, data);
break;
default:
ret = ptrace_request(child, request, addr, data);
break;
}
out_tsk:
put_task_struct(child);
out:
unlock_kernel();
return ret;
}
asmlinkage void syscall_trace(void)
{
struct task_struct *tsk = current;
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return;
if (!(tsk->ptrace & PT_PTRACED))
return;
ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
? 0x80 : 0));
/*
* this isn't the same as continuing with a signal, but it will do
* for normal use. strace only continues with a signal if the
* stopping signal is not SIGTRAP. -brl
*/
if (tsk->exit_code) {
send_sig(tsk->exit_code, tsk, 1);
tsk->exit_code = 0;
}
}
/* Called with interrupts disabled */
asmlinkage void do_single_step(unsigned long long vec, struct pt_regs *regs)
{
/* This is called after a single step exception (DEBUGSS).
There is no need to change the PC, as it is a post-execution
exception, as entry.S does not do anything to the PC for DEBUGSS.
We need to clear the Single Step setting in SR to avoid
continually stepping. */
local_irq_enable();
regs->sr &= ~SR_SSTEP;
force_sig(SIGTRAP, current);
}
/* Called with interrupts disabled */
asmlinkage void do_software_break_point(unsigned long long vec,
struct pt_regs *regs)
{
/* We need to forward step the PC, to counteract the backstep done
in signal.c. */
local_irq_enable();
force_sig(SIGTRAP, current);
regs->pc += 4;
}
/*
* Called by kernel/ptrace.c when detaching..
*
* Make sure single step bits etc are not set.
*/
void ptrace_disable(struct task_struct *child)
{
/* nothing to do.. */
}
