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/*
* linux/arch/cris/kernel/ptrace.c
*
* Parts taken from the m68k port.
*
* Copyright (c) 2000, 2001 Axis Communications AB
*
* Authors: Bjorn Wesen
*
* $Log: ptrace.c,v $
* Revision 1.8 2001/11/12 18:26:21 pkj
* Fixed compiler warnings.
*
* Revision 1.7 2001/09/26 11:53:49 bjornw
* PTRACE_DETACH works more simple in 2.4.10
*
* Revision 1.6 2001/07/25 16:08:47 bjornw
* PTRACE_ATTACH bulk moved into arch-independant code in 2.4.7
*
* Revision 1.5 2001/03/26 14:24:28 orjanf
* * Changed loop condition.
* * Added comment documenting non-standard ptrace behaviour.
*
* Revision 1.4 2001/03/20 19:44:41 bjornw
* Use the user_regs macro instead of thread.esp0
*
* Revision 1.3 2000/12/18 23:45:25 bjornw
* Linux/CRIS first version
*
*
*/
#include <linux/kernel.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 <asm/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>
/*
* does not yet catch signals sent when the child dies.
* in exit.c or in signal.c.
*/
/* determines which bits in DCCR the user has access to. */
/* 1 = access 0 = no access */
#define DCCR_MASK 0x0000001f /* XNZVC */
/*
* Get contents of register REGNO in task TASK.
*/
static inline long get_reg(struct task_struct *task, unsigned int regno)
{
/* USP is a special case, it's not in the pt_regs struct but
* in the tasks thread struct
*/
if (regno == PT_USP)
return task->thread.usp;
else if (regno < PT_MAX)
return ((unsigned long *)user_regs(task))[regno];
else
return 0;
}
/*
* Write contents of register REGNO in task TASK.
*/
static inline int put_reg(struct task_struct *task, unsigned int regno,
unsigned long data)
{
if (regno == PT_USP)
task->thread.usp = data;
else if (regno < PT_MAX)
((unsigned long *)user_regs(task))[regno] = data;
else
return -1;
return 0;
}
/*
* Called by kernel/ptrace.c when detaching..
*
* Make sure the single step bit is not set.
*/
void ptrace_disable(struct task_struct *child)
{
/* Todo - pending singlesteps? */
}
/* Note that this implementation of ptrace behaves differently from vanilla
* ptrace. Contrary to what the man page says, in the PTRACE_PEEKTEXT,
* PTRACE_PEEKDATA, and PTRACE_PEEKUSER requests the data variable is not
* ignored. Instead, the data variable is expected to point at a location
* (in user space) where the result of the ptrace call is written (instead of
* being returned).
*/
asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
{
struct task_struct *child;
int ret;
lock_kernel();
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 = -ESRCH;
if (!(child->ptrace & PT_PTRACED))
goto out_tsk;
if (child->state != TASK_STOPPED) {
if (request != PTRACE_KILL)
goto out_tsk;
}
if (child->p_pptr != current)
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 || addr >= sizeof(struct user))
break;
tmp = 0; /* Default return condition */
ret = -EIO;
if (addr < sizeof(struct pt_regs)) {
tmp = get_reg(child, addr >> 2);
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 */
ret = -EIO;
if ((addr & 3) || addr < 0 || addr >= sizeof(struct user))
break;
if (addr < sizeof(struct pt_regs)) {
addr >>= 2;
if (addr == PT_DCCR) {
/* don't allow the tracing process to change stuff like
* interrupt enable, kernel/user bit, dma enables etc.
*/
data &= DCCR_MASK;
data |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
}
if (put_reg(child, addr, data))
break;
ret = 0;
}
break;
case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
case PTRACE_CONT: /* restart after signal. */
ret = -EIO;
if ((unsigned long) data > _NSIG)
break;
if (request == PTRACE_SYSCALL)
child->ptrace |= PT_TRACESYS;
else
child->ptrace &= ~PT_TRACESYS;
child->exit_code = data;
/* TODO: make sure any pending breakpoint is killed */
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->state == TASK_ZOMBIE) /* already dead */
break;
child->exit_code = SIGKILL;
/* TODO: make sure any pending breakpoint is killed */
wake_up_process(child);
break;
case PTRACE_SINGLESTEP: /* set the trap flag. */
ret = -EIO;
if ((unsigned long) data > _NSIG)
break;
child->ptrace &= ~PT_TRACESYS;
/* TODO: set some clever breakpoint mechanism... */
child->exit_code = data;
/* give it a chance to run. */
wake_up_process(child);
ret = 0;
break;
case PTRACE_DETACH:
ret = ptrace_detach(child, data);
break;
case PTRACE_GETREGS: { /* Get all gp regs from the child. */
int i;
unsigned long tmp;
for (i = 0; i <= PT_MAX; i++) {
tmp = get_reg(child, i);
if (put_user(tmp, (unsigned long *) data)) {
ret = -EFAULT;
break;
}
data += sizeof(long);
}
ret = 0;
break;
}
case PTRACE_SETREGS: { /* Set all gp regs in the child. */
int i;
unsigned long tmp;
for (i = 0; i <= PT_MAX; i++) {
if (get_user(tmp, (unsigned long *) data)) {
ret = -EFAULT;
break;
}
if (i == PT_DCCR) {
tmp &= DCCR_MASK;
tmp |= get_reg(child, PT_DCCR) & ~DCCR_MASK;
}
put_reg(child, i, tmp);
data += sizeof(long);
}
ret = 0;
break;
}
default:
ret = -EIO;
break;
}
out_tsk:
free_task_struct(child);
out:
unlock_kernel();
return ret;
}
asmlinkage void syscall_trace(void)
{
if ((current->ptrace & (PT_PTRACED | PT_TRACESYS)) !=
(PT_PTRACED | PT_TRACESYS))
return;
/* TODO: make a way to distinguish between a syscall stop and SIGTRAP
* delivery like in the i386 port ?
*/
current->exit_code = SIGTRAP;
current->state = TASK_STOPPED;
notify_parent(current, SIGCHLD);
schedule();
/*
* 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 (current->exit_code) {
send_sig(current->exit_code, current, 1);
current->exit_code = 0;
}
}
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