/*
* File: arch/blackfin/kernel/ptrace.c
* Based on: Taken from linux/kernel/ptrace.c
* Author: linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
*
* Created: 1/23/92
* Description:
*
* Modified:
* Copyright 2004-2006 Analog Devices Inc.
*
* Bugs: Enter bugs at http://blackfin.uclinux.org/
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see the file COPYING, or write
* to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#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 <linux/signal.h>
#include <linux/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>
#include <asm/asm-offsets.h>
#include <asm/dma.h>
#include <asm/fixed_code.h>
#define MAX_SHARED_LIBS 3
#define TEXT_OFFSET 0
/*
* does not yet catch signals sent when the child dies.
* in exit.c or in signal.c.
*/
/* determines which bits in the SYSCFG reg the user has access to. */
/* 1 = access 0 = no access */
#define SYSCFG_MASK 0x0007 /* SYSCFG reg */
/* sets the trace bits. */
#define TRACE_BITS 0x0001
/* Find the stack offset for a register, relative to thread.esp0. */
#define PT_REG(reg) ((long)&((struct pt_regs *)0)->reg)
/*
* Get the address of the live pt_regs for the specified task.
* These are saved onto the top kernel stack when the process
* is not running.
*
* Note: if a user thread is execve'd from kernel space, the
* kernel stack will not be empty on entry to the kernel, so
* ptracing these tasks will fail.
*/
static inline struct pt_regs *get_user_regs(struct task_struct *task)
{
return (struct pt_regs *)
((unsigned long)task_stack_page(task) +
(THREAD_SIZE - sizeof(struct pt_regs)));
}
/*
* Get all user integer registers.
*/
static inline int ptrace_getregs(struct task_struct *tsk, void __user * uregs)
{
struct pt_regs *regs = get_user_regs(tsk);
return copy_to_user(uregs, regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
}
/* 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).
*/
/*
* Get contents of register REGNO in task TASK.
*/
static inline long get_reg(struct task_struct *task, int regno)
{
unsigned char *reg_ptr;
struct pt_regs *regs =
(struct pt_regs *)((unsigned long)task_stack_page(task) +
(THREAD_SIZE - sizeof(struct pt_regs)));
reg_ptr = (char *)regs;
switch (regno) {
case PT_USP:
return task->thread.usp;
default:
if (regno <= 216)
return *(long *)(reg_ptr + regno);
}
/* slight mystery ... never seems to come here but kernel misbehaves without this code! */
printk(KERN_WARNING "Request to get for unknown register %d\n", regno);
return 0;
}
/*
* Write contents of register REGNO in task TASK.
*/
static inline int
put_reg(struct task_struct *task, int regno, unsigned long data)
{
char *reg_ptr;
struct pt_regs *regs =
(struct pt_regs *)((unsigned long)task_stack_page(task) +
(THREAD_SIZE - sizeof(struct pt_regs)));
reg_ptr = (char *)regs;
switch (regno) {
case PT_PC:
/*********************************************************************/
/* At this point the kernel is most likely in exception. */
/* The RETX register will be used to populate the pc of the process. */
/*********************************************************************/
regs->retx = data;
regs->pc = data;
break;
case PT_RETX:
break; /* regs->retx = data; break; */
case PT_USP:
regs->usp = data;
task->thread.usp = data;
break;
default:
if (regno <= 216)
*(long *)(reg_ptr + regno) = data;
}
return 0;
}
/*
* check that an address falls within the bounds of the target process's memory mappings
*/
static inline int is_user_addr_valid(struct task_struct *child,
unsigned long start, unsigned long len)
{
struct vm_list_struct *vml;
struct sram_list_struct *sraml;
for (vml = child->mm->context.vmlist; vml; vml = vml->next)
if (start >= vml->vma->vm_start && start + len <= vml->vma->vm_end)
return 0;
for (sraml = child->mm->context.sram_list; sraml; sraml = sraml->next)
if (start >= (unsigned long)sraml->addr
&& start + len <= (unsigned long)sraml->addr + sraml->length)
return 0;
if (start >= FIXED_CODE_START && start + len <= FIXED_CODE_END)
return 0;
return -EIO;
}
/*
* Called by kernel/ptrace.c when detaching..
*
* Make sure the single step bit is not set.
*/
void ptrace_disable(struct task_struct *child)
{
unsigned long tmp;
/* make sure the single step bit is not set. */
tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
put_reg(child, PT_SR, tmp);
}
long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
int ret;
int add = 0;
unsigned long __user *datap = (unsigned long __user *)data;
switch (request) {
/* when I and D space are separate, these will need to be fixed. */
case PTRACE_PEEKDATA:
pr_debug("ptrace: PEEKDATA\n");
add = MAX_SHARED_LIBS * 4; /* space between text and data */
/* fall through */
case PTRACE_PEEKTEXT: /* read word at location addr. */
{
unsigned long tmp = 0;
int copied;
ret = -EIO;
pr_debug("ptrace: PEEKTEXT at addr 0x%08lx + add %d %ld\n", addr, add,
sizeof(data));
if (is_user_addr_valid(child, addr + add, sizeof(tmp)) < 0)
break;
pr_debug("ptrace: user address is valid\n");
#if L1_CODE_LENGTH != 0
if (addr + add >= L1_CODE_START
&& addr + add + sizeof(tmp) <= L1_CODE_START + L1_CODE_LENGTH) {
safe_dma_memcpy (&tmp, (const void *)(addr + add), sizeof(tmp));
copied = sizeof(tmp);
} else
#endif
if (addr + add >= FIXED_CODE_START
&& addr + add + sizeof(tmp) <= FIXED_CODE_END) {
memcpy(&tmp, (const void *)(addr + add), sizeof(tmp));
copied = sizeof(tmp);
} else
copied = access_process_vm(child, addr + add, &tmp,
sizeof(tmp), 0);
pr_debug("ptrace: copied size %d [0x%08lx]\n", copied, tmp);
if (copied != sizeof(tmp))
break;
ret = put_user(tmp, datap);
break;
}
/* read the word at location addr in the USER area. */
case PTRACE_PEEKUSR:
{
unsigned long tmp;
ret = -EIO;
tmp = 0;
if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
printk(KERN_WARNING "ptrace error : PEEKUSR : temporarily returning "
"0 - %x sizeof(pt_regs) is %lx\n",
(int)addr, sizeof(struct pt_regs));
break;
}
if (addr == sizeof(struct pt_regs)) {
/* PT_TEXT_ADDR */
tmp = child->mm->start_code + TEXT_OFFSET;
} else if (addr == (sizeof(struct pt_regs) + 4)) {
/* PT_TEXT_END_ADDR */
tmp = child->mm->end_code;
} else if (addr == (sizeof(struct pt_regs) + 8)) {
/* PT_DATA_ADDR */
tmp = child->mm->start_data;
#ifdef CONFIG_BINFMT_ELF_FDPIC
} else if (addr == (sizeof(struct pt_regs) + 12)) {
tmp = child->mm->context.exec_fdpic_loadmap;
} else if (addr == (sizeof(struct pt_regs) + 16)) {
tmp = child->mm->context.interp_fdpic_loadmap;
#endif
} else {
tmp = get_reg(child, addr);
}
ret = put_user(tmp, datap);
break;
}
/* when I and D space are separate, this will have to be fixed. */
case PTRACE_POKEDATA:
printk(KERN_NOTICE "ptrace: PTRACE_PEEKDATA\n");
/* fall through */
case PTRACE_POKETEXT: /* write the word at location addr. */
{
int copied;
ret = -EIO;
pr_debug("ptrace: POKETEXT at addr 0x%08lx + add %d %ld bytes %lx\n",
addr, add, sizeof(data), data);
if (is_user_addr_valid(child, addr + add, sizeof(data)) < 0)
break;
pr_debug("ptrace: user address is valid\n");
#if L1_CODE_LENGTH != 0
if (addr + add >= L1_CODE_START
&& addr + add + sizeof(data) <= L1_CODE_START + L1_CODE_LENGTH) {
safe_dma_memcpy ((void *)(addr + add), &data, sizeof(data));
copied = sizeof(data);
} else
#endif
if (addr + add >= FIXED_CODE_START
&& addr + add + sizeof(data) <= FIXED_CODE_END) {
memcpy((void *)(addr + add), &data, sizeof(data));
copied = sizeof(data);
} else
copied = access_process_vm(child, addr + add, &data,
sizeof(data), 1);
pr_debug("ptrace: copied size %d\n", copied);
if (copied != sizeof(data))
break;
ret = 0;
break;
}
case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
ret = -EIO;
if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
printk(KERN_WARNING "ptrace error : POKEUSR: temporarily returning 0\n");
break;
}
if (addr >= (sizeof(struct pt_regs))) {
ret = 0;
break;
}
if (addr == PT_SYSCFG) {
data &= SYSCFG_MASK;
data |= get_reg(child, PT_SYSCFG);
}
ret = put_reg(child, addr, data);
break;
case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
case PTRACE_CONT:
{ /* restart after signal. */
long tmp;
pr_debug("ptrace_cont\n");
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;
/* make sure the single step bit is not set. */
tmp = get_reg(child, PT_SYSCFG) & ~(TRACE_BITS);
put_reg(child, PT_SYSCFG, tmp);
pr_debug("before wake_up_process\n");
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:
{
long tmp;
ret = 0;
if (child->exit_state == EXIT_ZOMBIE) /* already dead */
break;
child->exit_code = SIGKILL;
/* make sure the single step bit is not set. */
tmp = get_reg(child, PT_SYSCFG) & ~(TRACE_BITS);
put_reg(child, PT_SYSCFG, tmp);
wake_up_process(child);
break;
}
case PTRACE_SINGLESTEP:
{ /* set the trap flag. */
long tmp;
pr_debug("single step\n");
ret = -EIO;
if (!valid_signal(data))
break;
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
tmp = get_reg(child, PT_SYSCFG) | (TRACE_BITS);
put_reg(child, PT_SYSCFG, tmp);
child->exit_code = data;
/* give it a chance to run. */
wake_up_process(child);
ret = 0;
break;
}
case PTRACE_GETREGS:
{
/* Get all gp regs from the child. */
ret = ptrace_getregs(child, datap);
break;
}
case PTRACE_SETREGS:
{
printk(KERN_NOTICE
"ptrace: SETREGS: **** NOT IMPLEMENTED ***\n");
/* Set all gp regs in the child. */
ret = 0;
break;
}
default:
ret = ptrace_request(child, request, addr, data);
break;
}
return ret;
}
asmlinkage void syscall_trace(void)
{
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return;
if (!(current->ptrace & PT_PTRACED))
return;
/* the 0x80 provides a way for the tracing parent to distinguish
* between a syscall stop and SIGTRAP delivery
*/
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 (current->exit_code) {
send_sig(current->exit_code, current, 1);
current->exit_code = 0;
}
}
