/*
* linux/arch/m68k/kernel/ptrace.c
*
* Copyright (C) 1994 by Hamish Macdonald
* Taken from linux/kernel/ptrace.c and modified for M680x0.
* linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
*
* 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 <stddef.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <asm/segment.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
/*
* does not yet catch signals sent when the child dies.
* in exit.c or in signal.c.
*/
/* determines which bits in the SR the user has access to. */
/* 1 = access 0 = no access */
#define SR_MASK 0x001f
/* sets the trace bits. */
#define TRACE_BITS 0x8000
/* Find the stack offset for a register, relative to tss.esp0. */
#define PT_REG(reg) ((long)&((struct pt_regs *)0)->reg)
#define SW_REG(reg) ((long)&((struct switch_stack *)0)->reg \
- sizeof(struct switch_stack))
/* Mapping from PT_xxx to the stack offset at which the register is
saved. Notice that usp has no stack-slot and needs to be treated
specially (see get_reg/put_reg below). */
static int regoff[] = {
PT_REG(d1), PT_REG(d2), PT_REG(d3), PT_REG(d4),
PT_REG(d5), SW_REG(d6), SW_REG(d7), PT_REG(a0),
PT_REG(a1), SW_REG(a2), SW_REG(a3), SW_REG(a4),
SW_REG(a5), SW_REG(a6), PT_REG(d0), -1,
PT_REG(orig_d0), PT_REG(sr), PT_REG(pc),
};
/* change a pid into a task struct. */
static inline struct task_struct * get_task(int pid)
{
int i;
for (i = 1; i < NR_TASKS; i++) {
if (task[i] != NULL && (task[i]->pid == pid))
return task[i];
}
return NULL;
}
/*
* Get contents of register REGNO in task TASK.
*/
static inline long get_reg(struct task_struct *task, int regno)
{
unsigned long *addr;
if (regno == PT_USP)
addr = &task->tss.usp;
else if (regno < sizeof(regoff)/sizeof(regoff[0]))
addr = (unsigned long *)(task->tss.esp0 + regoff[regno]);
else
return 0;
return *addr;
}
/*
* Write contents of register REGNO in task TASK.
*/
static inline int put_reg(struct task_struct *task, int regno,
unsigned long data)
{
unsigned long *addr;
if (regno == PT_USP)
addr = &task->tss.usp;
else if (regno < sizeof(regoff)/sizeof(regoff[0]))
addr = (unsigned long *) (task->tss.esp0 + regoff[regno]);
else
return -1;
*addr = data;
return 0;
}
/*
* This routine gets a long from any process space by following the page
* tables. NOTE! You should check that the long isn't on a page boundary,
* and that it is in the task area before calling this: this routine does
* no checking.
*
*/
static unsigned long get_long(struct task_struct * tsk,
struct vm_area_struct * vma, unsigned long addr)
{
pgd_t * pgdir;
pmd_t * pgmiddle;
pte_t * pgtable;
unsigned long page;
repeat:
pgdir = pgd_offset(vma->vm_mm, addr);
if (pgd_none(*pgdir)) {
do_no_page(tsk, vma, addr, 0);
goto repeat;
}
if (pgd_bad(*pgdir)) {
printk("ptrace: bad page directory %08lx\n", pgd_val(*pgdir));
pgd_clear(pgdir);
return 0;
}
pgmiddle = pmd_offset(pgdir,addr);
if (pmd_none(*pgmiddle)) {
do_no_page(tsk, vma, addr, 0);
goto repeat;
}
if (pmd_bad(*pgmiddle)) {
printk("ptrace: bad page directory %08lx\n",
pmd_val(*pgmiddle));
pmd_clear(pgmiddle);
return 0;
}
pgtable = pte_offset(pgmiddle, addr);
if (!pte_present(*pgtable)) {
do_no_page(tsk, vma, addr, 0);
goto repeat;
}
page = pte_page(*pgtable);
/* this is a hack for non-kernel-mapped video buffers and similar */
if (page >= high_memory)
return 0;
page += addr & ~PAGE_MASK;
return *(unsigned long *) page;
}
/*
* This routine puts a long into any process space by following the page
* tables. NOTE! You should check that the long isn't on a page boundary,
* and that it is in the task area before calling this: this routine does
* no checking.
*
* Now keeps R/W state of page so that a text page stays readonly
* even if a debugger scribbles breakpoints into it. -M.U-
*/
static void put_long(struct task_struct * tsk, struct vm_area_struct * vma, unsigned long addr,
unsigned long data)
{
pgd_t *pgdir;
pmd_t *pgmiddle;
pte_t *pgtable;
unsigned long page;
repeat:
pgdir = pgd_offset(vma->vm_mm, addr);
if (!pgd_present(*pgdir)) {
do_no_page(tsk, vma, addr, 1);
goto repeat;
}
if (pgd_bad(*pgdir)) {
printk("ptrace: bad page directory %08lx\n", pgd_val(*pgdir));
pgd_clear(pgdir);
return;
}
pgmiddle = pmd_offset(pgdir,addr);
if (pmd_none(*pgmiddle)) {
do_no_page(tsk, vma, addr, 1);
goto repeat;
}
if (pmd_bad(*pgmiddle)) {
printk("ptrace: bad page directory %08lx\n",
pmd_val(*pgmiddle));
pmd_clear(pgmiddle);
return;
}
pgtable = pte_offset(pgmiddle, addr);
if (!pte_present(*pgtable)) {
do_no_page(tsk, vma, addr, 1);
goto repeat;
}
page = pte_page(*pgtable);
if (!pte_write(*pgtable)) {
do_wp_page(tsk, vma, addr, 2);
goto repeat;
}
/* this is a hack for non-kernel-mapped video buffers and similar */
if (page < high_memory) {
*(unsigned long *) (page + (addr & ~PAGE_MASK)) = data;
}
/* we're bypassing pagetables, so we have to set the dirty bit ourselves */
/* this should also re-instate whatever read-only mode there was before */
*pgtable = pte_mkdirty(mk_pte(page, vma->vm_page_prot));
flush_tlb_all();
}
static struct vm_area_struct * find_extend_vma(struct task_struct * tsk, unsigned long addr)
{
struct vm_area_struct * vma;
addr &= PAGE_MASK;
vma = find_vma(tsk,addr);
if (!vma)
return NULL;
if (vma->vm_start <= addr)
return vma;
if (!(vma->vm_flags & VM_GROWSDOWN))
return NULL;
if (vma->vm_end - addr > tsk->rlim[RLIMIT_STACK].rlim_cur)
return NULL;
vma->vm_offset -= vma->vm_start - addr;
vma->vm_start = addr;
return vma;
}
/*
* This routine checks the page boundaries, and that the offset is
* within the task area. It then calls get_long() to read a long.
*/
static int read_long(struct task_struct * tsk, unsigned long addr,
unsigned long * result)
{
struct vm_area_struct * vma = find_extend_vma(tsk, addr);
if (!vma)
return -EIO;
if ((addr & ~PAGE_MASK) > PAGE_SIZE-sizeof(long)) {
unsigned long low,high;
struct vm_area_struct * vma_low = vma;
if (addr + sizeof(long) >= vma->vm_end) {
vma_low = vma->vm_next;
if (!vma_low || vma_low->vm_start != vma->vm_end)
return -EIO;
}
high = get_long(tsk, vma,addr & ~(sizeof(long)-1));
low = get_long(tsk, vma_low,(addr+sizeof(long)) & ~(sizeof(long)-1));
switch (addr & (sizeof(long)-1)) {
case 3:
low >>= 8;
low |= high << 24;
break;
case 2:
low >>= 16;
low |= high << 16;
break;
case 1:
low >>= 24;
low |= high << 8;
break;
}
*result = low;
} else
*result = get_long(tsk, vma,addr);
return 0;
}
/*
* This routine checks the page boundaries, and that the offset is
* within the task area. It then calls put_long() to write a long.
*/
static int write_long(struct task_struct * tsk, unsigned long addr,
unsigned long data)
{
struct vm_area_struct * vma = find_extend_vma(tsk, addr);
if (!vma)
return -EIO;
if ((addr & ~PAGE_MASK) > PAGE_SIZE-sizeof(long)) {
unsigned long low,high;
struct vm_area_struct * vma_low = vma;
if (addr + sizeof(long) >= vma->vm_end) {
vma_low = vma->vm_next;
if (!vma_low || vma_low->vm_start != vma->vm_end)
return -EIO;
}
high = get_long(tsk, vma,addr & ~(sizeof(long)-1));
low = get_long(tsk, vma_low,(addr+sizeof(long)) & ~(sizeof(long)-1));
switch (addr & (sizeof(long)-1)) {
case 0: /* shouldn't happen, but safety first */
high = data;
break;
case 3:
low &= 0x000000ff;
low |= data << 8;
high &= ~0xff;
high |= data >> 24;
break;
case 2:
low &= 0x0000ffff;
low |= data << 16;
high &= ~0xffff;
high |= data >> 16;
break;
case 1:
low &= 0x00ffffff;
low |= data << 24;
high &= ~0xffffff;
high |= data >> 8;
break;
}
put_long(tsk, vma,addr & ~(sizeof(long)-1),high);
put_long(tsk, vma_low,(addr+sizeof(long)) & ~(sizeof(long)-1),low);
} else
put_long(tsk, vma,addr,data);
return 0;
}
asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
{
struct task_struct *child;
struct user * dummy;
dummy = NULL;
if (request == PTRACE_TRACEME) {
/* are we already being traced? */
if (current->flags & PF_PTRACED)
return -EPERM;
/* set the ptrace bit in the process flags. */
current->flags |= PF_PTRACED;
return 0;
}
if (pid == 1) /* you may not mess with init */
return -EPERM;
if (!(child = get_task(pid)))
return -ESRCH;
if (request == PTRACE_ATTACH) {
if (child == current)
return -EPERM;
if ((!child->dumpable ||
(current->uid != child->euid) ||
(current->uid != child->suid) ||
(current->uid != child->uid) ||
(current->gid != child->egid) ||
(current->gid != child->sgid) ||
(current->gid != child->gid)) && !suser())
return -EPERM;
/* the same process cannot be attached many times */
if (child->flags & PF_PTRACED)
return -EPERM;
child->flags |= PF_PTRACED;
if (child->p_pptr != current) {
REMOVE_LINKS(child);
child->p_pptr = current;
SET_LINKS(child);
}
send_sig(SIGSTOP, child, 1);
return 0;
}
if (!(child->flags & PF_PTRACED))
return -ESRCH;
if (child->state != TASK_STOPPED) {
if (request != PTRACE_KILL)
return -ESRCH;
}
if (child->p_pptr != current)
return -ESRCH;
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 res;
res = read_long(child, addr, &tmp);
if (res < 0)
return res;
res = verify_area(VERIFY_WRITE, (void *) data, sizeof(long));
if (!res)
put_user(tmp, (unsigned long *) data);
return res;
}
/* read the word at location addr in the USER area. */
case PTRACE_PEEKUSR: {
unsigned long tmp;
int res;
if ((addr & 3) || addr < 0 || addr >= sizeof(struct user))
return -EIO;
res = verify_area(VERIFY_WRITE, (void *) data,
sizeof(long));
if (res)
return res;
tmp = 0; /* Default return condition */
addr = addr >> 2; /* temporary hack. */
if (addr < 19) {
tmp = get_reg(child, addr);
if (addr == PT_SR)
tmp >>= 16;
}
else if (addr >= 21 && addr < 49)
tmp = child->tss.fp[addr - 21];
else
return -EIO;
put_user(tmp,(unsigned long *) data);
return 0;
}
/* 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:
return write_long(child,addr,data);
case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
if ((addr & 3) || addr < 0 || addr >= sizeof(struct user))
return -EIO;
addr = addr >> 2; /* temporary hack. */
if (addr == PT_ORIG_D0)
return -EIO;
if (addr == PT_SR) {
data &= SR_MASK;
data <<= 16;
data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
}
if (addr < 19) {
if (put_reg(child, addr, data))
return -EIO;
return 0;
}
if (addr >= 21 && addr < 48)
{
child->tss.fp[addr - 21] = data;
return 0;
}
return -EIO;
case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
case PTRACE_CONT: { /* restart after signal. */
long tmp;
if ((unsigned long) data >= NSIG)
return -EIO;
if (request == PTRACE_SYSCALL)
child->flags |= PF_TRACESYS;
else
child->flags &= ~PF_TRACESYS;
child->exit_code = data;
wake_up_process(child);
/* make sure the single step bit is not set. */
tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
put_reg(child, PT_SR, tmp);
return 0;
}
/*
* 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: {
long tmp;
if (child->state == TASK_ZOMBIE) /* already dead */
return 0;
wake_up_process(child);
child->exit_code = SIGKILL;
/* make sure the single step bit is not set. */
tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
put_reg(child, PT_SR, tmp);
return 0;
}
case PTRACE_SINGLESTEP: { /* set the trap flag. */
long tmp;
if ((unsigned long) data >= NSIG)
return -EIO;
child->flags &= ~PF_TRACESYS;
tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
put_reg(child, PT_SR, tmp);
wake_up_process(child);
child->exit_code = data;
/* give it a chance to run. */
return 0;
}
case PTRACE_DETACH: { /* detach a process that was attached. */
long tmp;
if ((unsigned long) data >= NSIG)
return -EIO;
child->flags &= ~(PF_PTRACED|PF_TRACESYS);
wake_up_process(child);
child->exit_code = data;
REMOVE_LINKS(child);
child->p_pptr = child->p_opptr;
SET_LINKS(child);
/* make sure the single step bit is not set. */
tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
put_reg(child, PT_SR, tmp);
return 0;
}
default:
return -EIO;
}
}
asmlinkage void syscall_trace(void)
{
if ((current->flags & (PF_PTRACED|PF_TRACESYS))
!= (PF_PTRACED|PF_TRACESYS))
return;
current->exit_code = SIGTRAP;
current->state = TASK_STOPPED;
notify_parent(current);
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)
current->signal |= (1 << (current->exit_code - 1));
current->exit_code = 0;
return;
}
