/*
* arch/ppc/kernel/ptrace.c
*
* PowerPC version
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Derived from "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
*
* Modified by Cort Dougan (cort@hq.fsmlabs.com)
* and Paul Mackerras (paulus@linuxcare.com.au).
*
* This file is subject to the terms and conditions of the GNU General
* Public License. See the file README.legal in the main directory of
* this archive for more details.
*/
#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/security.h>
#include <linux/signal.h>
#include <linux/seccomp.h>
#include <linux/audit.h>
#include <linux/module.h>
#include <asm/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
/*
* Set of msr bits that gdb can change on behalf of a process.
*/
#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
#define MSR_DEBUGCHANGE 0
#else
#define MSR_DEBUGCHANGE (MSR_SE | MSR_BE)
#endif
/*
* does not yet catch signals sent when the child dies.
* in exit.c or in signal.c.
*/
/*
* Get contents of register REGNO in task TASK.
*/
static inline unsigned long get_reg(struct task_struct *task, int regno)
{
if (regno < sizeof(struct pt_regs) / sizeof(unsigned long)
&& task->thread.regs != NULL)
return ((unsigned long *)task->thread.regs)[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)
{
if (regno <= PT_MQ && task->thread.regs != NULL) {
if (regno == PT_MSR)
data = (data & MSR_DEBUGCHANGE)
| (task->thread.regs->msr & ~MSR_DEBUGCHANGE);
((unsigned long *)task->thread.regs)[regno] = data;
return 0;
}
return -EIO;
}
#ifdef CONFIG_ALTIVEC
/*
* Get contents of AltiVec register state in task TASK
*/
static inline int get_vrregs(unsigned long __user *data, struct task_struct *task)
{
int i, j;
if (!access_ok(VERIFY_WRITE, data, 133 * sizeof(unsigned long)))
return -EFAULT;
/* copy AltiVec registers VR[0] .. VR[31] */
for (i = 0; i < 32; i++)
for (j = 0; j < 4; j++, data++)
if (__put_user(task->thread.vr[i].u[j], data))
return -EFAULT;
/* copy VSCR */
for (i = 0; i < 4; i++, data++)
if (__put_user(task->thread.vscr.u[i], data))
return -EFAULT;
/* copy VRSAVE */
if (__put_user(task->thread.vrsave, data))
return -EFAULT;
return 0;
}
/*
* Write contents of AltiVec register state into task TASK.
*/
static inline int set_vrregs(struct task_struct *task, unsigned long __user *data)
{
int i, j;
if (!access_ok(VERIFY_READ, data, 133 * sizeof(unsigned long)))
return -EFAULT;
/* copy AltiVec registers VR[0] .. VR[31] */
for (i = 0; i < 32; i++)
for (j = 0; j < 4; j++, data++)
if (__get_user(task->thread.vr[i].u[j], data))
return -EFAULT;
/* copy VSCR */
for (i = 0; i < 4; i++, data++)
if (__get_user(task->thread.vscr.u[i], data))
return -EFAULT;
/* copy VRSAVE */
if (__get_user(task->thread.vrsave, data))
return -EFAULT;
return 0;
}
#endif
#ifdef CONFIG_SPE
/*
* For get_evrregs/set_evrregs functions 'data' has the following layout:
*
* struct {
* u32 evr[32];
* u64 acc;
* u32 spefscr;
* }
*/
/*
* Get contents of SPE register state in task TASK.
*/
static inline int get_evrregs(unsigned long *data, struct task_struct *task)
{
int i;
if (!access_ok(VERIFY_WRITE, data, 35 * sizeof(unsigned long)))
return -EFAULT;
/* copy SPEFSCR */
if (__put_user(task->thread.spefscr, &data[34]))
return -EFAULT;
/* copy SPE registers EVR[0] .. EVR[31] */
for (i = 0; i < 32; i++, data++)
if (__put_user(task->thread.evr[i], data))
return -EFAULT;
/* copy ACC */
if (__put_user64(task->thread.acc, (unsigned long long *)data))
return -EFAULT;
return 0;
}
/*
* Write contents of SPE register state into task TASK.
*/
static inline int set_evrregs(struct task_struct *task, unsigned long *data)
{
int i;
if (!access_ok(VERIFY_READ, data, 35 * sizeof(unsigned long)))
return -EFAULT;
/* copy SPEFSCR */
if (__get_user(task->thread.spefscr, &data[34]))
return -EFAULT;
/* copy SPE registers EVR[0] .. EVR[31] */
for (i = 0; i < 32; i++, data++)
if (__get_user(task->thread.evr[i], data))
return -EFAULT;
/* copy ACC */
if (__get_user64(task->thread.acc, (unsigned long long*)data))
return -EFAULT;
return 0;
}
#endif /* CONFIG_SPE */
static inline void
set_single_step(struct task_struct *task)
{
struct pt_regs *regs = task->thread.regs;
if (regs != NULL) {
#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
task->thread.dbcr0 = DBCR0_IDM | DBCR0_IC;
regs->msr |= MSR_DE;
#else
regs->msr |= MSR_SE;
#endif
}
}
static inline void
clear_single_step(struct task_struct *task)
{
struct pt_regs *regs = task->thread.regs;
if (regs != NULL) {
#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
task->thread.dbcr0 = 0;
regs->msr &= ~MSR_DE;
#else
regs->msr &= ~MSR_SE;
#endif
}
}
/*
* Called by kernel/ptrace.c when detaching..
*
* Make sure single step bits etc are not set.
*/
void ptrace_disable(struct task_struct *child)
{
/* make sure the single step bit is not set. */
clear_single_step(child);
}
int sys_ptrace(long request, long pid, long addr, long data)
{
struct task_struct *child;
int ret = -EPERM;
lock_kernel();
if (request == PTRACE_TRACEME) {
/* are we already being traced? */
if (current->ptrace & PT_PTRACED)
goto out;
ret = security_ptrace(current->parent, current);
if (ret)
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 __user *) data);
break;
}
/* read the word at location addr in the USER area. */
/* XXX this will need fixing for 64-bit */
case PTRACE_PEEKUSR: {
unsigned long index, tmp;
ret = -EIO;
/* convert to index and check */
index = (unsigned long) addr >> 2;
if ((addr & 3) || index > PT_FPSCR
|| child->thread.regs == NULL)
break;
CHECK_FULL_REGS(child->thread.regs);
if (index < PT_FPR0) {
tmp = get_reg(child, (int) index);
} else {
preempt_disable();
if (child->thread.regs->msr & MSR_FP)
giveup_fpu(child);
preempt_enable();
tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
}
ret = put_user(tmp,(unsigned long __user *) data);
break;
}
/* If 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;
/* write the word at location addr in the USER area */
case PTRACE_POKEUSR: {
unsigned long index;
ret = -EIO;
/* convert to index and check */
index = (unsigned long) addr >> 2;
if ((addr & 3) || index > PT_FPSCR
|| child->thread.regs == NULL)
break;
CHECK_FULL_REGS(child->thread.regs);
if (index == PT_ORIG_R3)
break;
if (index < PT_FPR0) {
ret = put_reg(child, index, data);
} else {
preempt_disable();
if (child->thread.regs->msr & MSR_FP)
giveup_fpu(child);
preempt_enable();
((unsigned long *)child->thread.fpr)[index - PT_FPR0] = data;
ret = 0;
}
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;
/* make sure the single step bit is not set. */
clear_single_step(child);
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;
/* make sure the single step bit is not set. */
clear_single_step(child);
wake_up_process(child);
break;
}
case PTRACE_SINGLESTEP: { /* set the trap flag. */
ret = -EIO;
if (!valid_signal(data))
break;
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
set_single_step(child);
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;
#ifdef CONFIG_ALTIVEC
case PTRACE_GETVRREGS:
/* Get the child altivec register state. */
preempt_disable();
if (child->thread.regs->msr & MSR_VEC)
giveup_altivec(child);
preempt_enable();
ret = get_vrregs((unsigned long __user *)data, child);
break;
case PTRACE_SETVRREGS:
/* Set the child altivec register state. */
/* this is to clear the MSR_VEC bit to force a reload
* of register state from memory */
preempt_disable();
if (child->thread.regs->msr & MSR_VEC)
giveup_altivec(child);
preempt_enable();
ret = set_vrregs(child, (unsigned long __user *)data);
break;
#endif
#ifdef CONFIG_SPE
case PTRACE_GETEVRREGS:
/* Get the child spe register state. */
if (child->thread.regs->msr & MSR_SPE)
giveup_spe(child);
ret = get_evrregs((unsigned long __user *)data, child);
break;
case PTRACE_SETEVRREGS:
/* Set the child spe register state. */
/* this is to clear the MSR_SPE bit to force a reload
* of register state from memory */
if (child->thread.regs->msr & MSR_SPE)
giveup_spe(child);
ret = set_evrregs(child, (unsigned long __user *)data);
break;
#endif
default:
ret = ptrace_request(child, request, addr, data);
break;
}
out_tsk:
put_task_struct(child);
out:
unlock_kernel();
return ret;
}
static void do_syscall_trace(void)
{
/* 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;
}
}
void do_syscall_trace_enter(struct pt_regs *regs)
{
if (test_thread_flag(TIF_SYSCALL_TRACE)
&& (current->ptrace & PT_PTRACED))
do_syscall_trace();
if (unlikely(current->audit_context))
audit_syscall_entry(current, AUDIT_ARCH_PPC,
regs->gpr[0],
regs->gpr[3], regs->gpr[4],
regs->gpr[5], regs->gpr[6]);
}
void do_syscall_trace_leave(struct pt_regs *regs)
{
secure_computing(regs->gpr[0]);
if (unlikely(current->audit_context))
audit_syscall_exit(current,
(regs->ccr&0x1000)?AUDITSC_FAILURE:AUDITSC_SUCCESS,
regs->result);
if ((test_thread_flag(TIF_SYSCALL_TRACE))
&& (current->ptrace & PT_PTRACED))
do_syscall_trace();
}
EXPORT_SYMBOL(do_syscall_trace_enter);
EXPORT_SYMBOL(do_syscall_trace_leave);
