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android_kernel_motorola_sm6225/arch/s390/kernel/ptrace.c
Gerald Schaefer c1821c2e97 [S390] noexec protection 
This provides a noexec protection on s390 hardware. Our hardware does
not have any bits left in the pte for a hw noexec bit, so this is a
different approach using shadow page tables and a special addressing
mode that allows separate address spaces for code and data.

As a special feature of our "secondary-space" addressing mode, separate
page tables can be specified for the translation of data addresses
(storage operands) and instruction addresses. The shadow page table is
used for the instruction addresses and the standard page table for the
data addresses.
The shadow page table is linked to the standard page table by a pointer
in page->lru.next of the struct page corresponding to the page that
contains the standard page table (since page->private is not really
private with the pte_lock and the page table pages are not in the LRU
list).
Depending on the software bits of a pte, it is either inserted into
both page tables or just into the standard (data) page table. Pages of
a vma that does not have the VM_EXEC bit set get mapped only in the
data address space. Any try to execute code on such a page will cause a
page translation exception. The standard reaction to this is a SIGSEGV
with two exceptions: the two system call opcodes 0x0a77 (sys_sigreturn)
and 0x0aad (sys_rt_sigreturn) are allowed. They are stored by the
kernel to the signal stack frame. Unfortunately, the signal return
mechanism cannot be modified to use an SA_RESTORER because the
exception unwinding code depends on the system call opcode stored
behind the signal stack frame.

This feature requires that user space is executed in secondary-space
mode and the kernel in home-space mode, which means that the addressing
modes need to be switched and that the noexec protection only works
for user space.
After switching the addressing modes, we cannot use the mvcp/mvcs
instructions anymore to copy between kernel and user space. A new
mvcos instruction has been added to the z9 EC/BC hardware which allows
to copy between arbitrary address spaces, but on older hardware the
page tables need to be walked manually.

Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-02-05 21:18:17 +01:00

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/*
* arch/s390/kernel/ptrace.c
*
* S390 version
* Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
* Martin Schwidefsky (schwidefsky@de.ibm.com)
*
* Based on 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@cs.nmt.edu)
*
*
* 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/audit.h>
#include <linux/signal.h>
#include <asm/segment.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#ifdef CONFIG_COMPAT
#include "compat_ptrace.h"
#endif
static void
FixPerRegisters(struct task_struct *task)
{
struct pt_regs *regs;
per_struct *per_info;
regs = task_pt_regs(task);
per_info = (per_struct *) &task->thread.per_info;
per_info->control_regs.bits.em_instruction_fetch =
per_info->single_step | per_info->instruction_fetch;
if (per_info->single_step) {
per_info->control_regs.bits.starting_addr = 0;
#ifdef CONFIG_COMPAT
if (test_thread_flag(TIF_31BIT))
per_info->control_regs.bits.ending_addr = 0x7fffffffUL;
else
#endif
per_info->control_regs.bits.ending_addr = PSW_ADDR_INSN;
} else {
per_info->control_regs.bits.starting_addr =
per_info->starting_addr;
per_info->control_regs.bits.ending_addr =
per_info->ending_addr;
}
/*
* if any of the control reg tracing bits are on
* we switch on per in the psw
*/
if (per_info->control_regs.words.cr[0] & PER_EM_MASK)
regs->psw.mask |= PSW_MASK_PER;
else
regs->psw.mask &= ~PSW_MASK_PER;
if (per_info->control_regs.bits.em_storage_alteration)
per_info->control_regs.bits.storage_alt_space_ctl = 1;
else
per_info->control_regs.bits.storage_alt_space_ctl = 0;
}
static void set_single_step(struct task_struct *task)
{
task->thread.per_info.single_step = 1;
FixPerRegisters(task);
}
static void clear_single_step(struct task_struct *task)
{
task->thread.per_info.single_step = 0;
FixPerRegisters(task);
}
/*
* 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);
}
#ifndef CONFIG_64BIT
# define __ADDR_MASK 3
#else
# define __ADDR_MASK 7
#endif
/*
* Read the word at offset addr from the user area of a process. The
* trouble here is that the information is littered over different
* locations. The process registers are found on the kernel stack,
* the floating point stuff and the trace settings are stored in
* the task structure. In addition the different structures in
* struct user contain pad bytes that should be read as zeroes.
* Lovely...
*/
static int
peek_user(struct task_struct *child, addr_t addr, addr_t data)
{
struct user *dummy = NULL;
addr_t offset, tmp, mask;
/*
* Stupid gdb peeks/pokes the access registers in 64 bit with
* an alignment of 4. Programmers from hell...
*/
mask = __ADDR_MASK;
#ifdef CONFIG_64BIT
if (addr >= (addr_t) &dummy->regs.acrs &&
addr < (addr_t) &dummy->regs.orig_gpr2)
mask = 3;
#endif
if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
return -EIO;
if (addr < (addr_t) &dummy->regs.acrs) {
/*
* psw and gprs are stored on the stack
*/
tmp = *(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr);
if (addr == (addr_t) &dummy->regs.psw.mask)
/* Remove per bit from user psw. */
tmp &= ~PSW_MASK_PER;
} else if (addr < (addr_t) &dummy->regs.orig_gpr2) {
/*
* access registers are stored in the thread structure
*/
offset = addr - (addr_t) &dummy->regs.acrs;
#ifdef CONFIG_64BIT
/*
* Very special case: old & broken 64 bit gdb reading
* from acrs[15]. Result is a 64 bit value. Read the
* 32 bit acrs[15] value and shift it by 32. Sick...
*/
if (addr == (addr_t) &dummy->regs.acrs[15])
tmp = ((unsigned long) child->thread.acrs[15]) << 32;
else
#endif
tmp = *(addr_t *)((addr_t) &child->thread.acrs + offset);
} else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
/*
* orig_gpr2 is stored on the kernel stack
*/
tmp = (addr_t) task_pt_regs(child)->orig_gpr2;
} else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
/*
* floating point regs. are stored in the thread structure
*/
offset = addr - (addr_t) &dummy->regs.fp_regs;
tmp = *(addr_t *)((addr_t) &child->thread.fp_regs + offset);
if (addr == (addr_t) &dummy->regs.fp_regs.fpc)
tmp &= (unsigned long) FPC_VALID_MASK
<< (BITS_PER_LONG - 32);
} else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
/*
* per_info is found in the thread structure
*/
offset = addr - (addr_t) &dummy->regs.per_info;
tmp = *(addr_t *)((addr_t) &child->thread.per_info + offset);
} else
tmp = 0;
return put_user(tmp, (addr_t __user *) data);
}
/*
* Write a word to the user area of a process at location addr. This
* operation does have an additional problem compared to peek_user.
* Stores to the program status word and on the floating point
* control register needs to get checked for validity.
*/
static int
poke_user(struct task_struct *child, addr_t addr, addr_t data)
{
struct user *dummy = NULL;
addr_t offset, mask;
/*
* Stupid gdb peeks/pokes the access registers in 64 bit with
* an alignment of 4. Programmers from hell indeed...
*/
mask = __ADDR_MASK;
#ifdef CONFIG_64BIT
if (addr >= (addr_t) &dummy->regs.acrs &&
addr < (addr_t) &dummy->regs.orig_gpr2)
mask = 3;
#endif
if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
return -EIO;
if (addr < (addr_t) &dummy->regs.acrs) {
/*
* psw and gprs are stored on the stack
*/
if (addr == (addr_t) &dummy->regs.psw.mask &&
#ifdef CONFIG_COMPAT
data != PSW_MASK_MERGE(psw_user32_bits, data) &&
#endif
data != PSW_MASK_MERGE(psw_user_bits, data))
/* Invalid psw mask. */
return -EINVAL;
#ifndef CONFIG_64BIT
if (addr == (addr_t) &dummy->regs.psw.addr)
/* I'd like to reject addresses without the
high order bit but older gdb's rely on it */
data |= PSW_ADDR_AMODE;
#endif
*(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr) = data;
} else if (addr < (addr_t) (&dummy->regs.orig_gpr2)) {
/*
* access registers are stored in the thread structure
*/
offset = addr - (addr_t) &dummy->regs.acrs;
#ifdef CONFIG_64BIT
/*
* Very special case: old & broken 64 bit gdb writing
* to acrs[15] with a 64 bit value. Ignore the lower
* half of the value and write the upper 32 bit to
* acrs[15]. Sick...
*/
if (addr == (addr_t) &dummy->regs.acrs[15])
child->thread.acrs[15] = (unsigned int) (data >> 32);
else
#endif
*(addr_t *)((addr_t) &child->thread.acrs + offset) = data;
} else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
/*
* orig_gpr2 is stored on the kernel stack
*/
task_pt_regs(child)->orig_gpr2 = data;
} else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
/*
* floating point regs. are stored in the thread structure
*/
if (addr == (addr_t) &dummy->regs.fp_regs.fpc &&
(data & ~((unsigned long) FPC_VALID_MASK
<< (BITS_PER_LONG - 32))) != 0)
return -EINVAL;
offset = addr - (addr_t) &dummy->regs.fp_regs;
*(addr_t *)((addr_t) &child->thread.fp_regs + offset) = data;
} else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
/*
* per_info is found in the thread structure
*/
offset = addr - (addr_t) &dummy->regs.per_info;
*(addr_t *)((addr_t) &child->thread.per_info + offset) = data;
}
FixPerRegisters(child);
return 0;
}
static int
do_ptrace_normal(struct task_struct *child, long request, long addr, long data)
{
unsigned long tmp;
ptrace_area parea;
int copied, ret;
switch (request) {
case PTRACE_PEEKTEXT:
case PTRACE_PEEKDATA:
/* Remove high order bit from address (only for 31 bit). */
addr &= PSW_ADDR_INSN;
/* read word at location addr. */
copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
if (copied != sizeof(tmp))
return -EIO;
return put_user(tmp, (unsigned long __force __user *) data);
case PTRACE_PEEKUSR:
/* read the word at location addr in the USER area. */
return peek_user(child, addr, data);
case PTRACE_POKETEXT:
case PTRACE_POKEDATA:
/* Remove high order bit from address (only for 31 bit). */
addr &= PSW_ADDR_INSN;
/* write the word at location addr. */
copied = access_process_vm(child, addr, &data, sizeof(data),1);
if (copied != sizeof(data))
return -EIO;
return 0;
case PTRACE_POKEUSR:
/* write the word at location addr in the USER area */
return poke_user(child, addr, data);
case PTRACE_PEEKUSR_AREA:
case PTRACE_POKEUSR_AREA:
if (copy_from_user(&parea, (void __force __user *) addr,
sizeof(parea)))
return -EFAULT;
addr = parea.kernel_addr;
data = parea.process_addr;
copied = 0;
while (copied < parea.len) {
if (request == PTRACE_PEEKUSR_AREA)
ret = peek_user(child, addr, data);
else {
addr_t utmp;
if (get_user(utmp,
(addr_t __force __user *) data))
return -EFAULT;
ret = poke_user(child, addr, utmp);
}
if (ret)
return ret;
addr += sizeof(unsigned long);
data += sizeof(unsigned long);
copied += sizeof(unsigned long);
}
return 0;
}
return ptrace_request(child, request, addr, data);
}
#ifdef CONFIG_COMPAT
/*
* Now the fun part starts... a 31 bit program running in the
* 31 bit emulation tracing another program. PTRACE_PEEKTEXT,
* PTRACE_PEEKDATA, PTRACE_POKETEXT and PTRACE_POKEDATA are easy
* to handle, the difference to the 64 bit versions of the requests
* is that the access is done in multiples of 4 byte instead of
* 8 bytes (sizeof(unsigned long) on 31/64 bit).
* The ugly part are PTRACE_PEEKUSR, PTRACE_PEEKUSR_AREA,
* PTRACE_POKEUSR and PTRACE_POKEUSR_AREA. If the traced program
* is a 31 bit program too, the content of struct user can be
* emulated. A 31 bit program peeking into the struct user of
* a 64 bit program is a no-no.
*/
/*
* Same as peek_user but for a 31 bit program.
*/
static int
peek_user_emu31(struct task_struct *child, addr_t addr, addr_t data)
{
struct user32 *dummy32 = NULL;
per_struct32 *dummy_per32 = NULL;
addr_t offset;
__u32 tmp;
if (!test_thread_flag(TIF_31BIT) ||
(addr & 3) || addr > sizeof(struct user) - 3)
return -EIO;
if (addr < (addr_t) &dummy32->regs.acrs) {
/*
* psw and gprs are stored on the stack
*/
if (addr == (addr_t) &dummy32->regs.psw.mask) {
/* Fake a 31 bit psw mask. */
tmp = (__u32)(task_pt_regs(child)->psw.mask >> 32);
tmp = PSW32_MASK_MERGE(psw32_user_bits, tmp);
} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
/* Fake a 31 bit psw address. */
tmp = (__u32) task_pt_regs(child)->psw.addr |
PSW32_ADDR_AMODE31;
} else {
/* gpr 0-15 */
tmp = *(__u32 *)((addr_t) &task_pt_regs(child)->psw +
addr*2 + 4);
}
} else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
/*
* access registers are stored in the thread structure
*/
offset = addr - (addr_t) &dummy32->regs.acrs;
tmp = *(__u32*)((addr_t) &child->thread.acrs + offset);
} else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
/*
* orig_gpr2 is stored on the kernel stack
*/
tmp = *(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4);
} else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
/*
* floating point regs. are stored in the thread structure
*/
offset = addr - (addr_t) &dummy32->regs.fp_regs;
tmp = *(__u32 *)((addr_t) &child->thread.fp_regs + offset);
} else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
/*
* per_info is found in the thread structure
*/
offset = addr - (addr_t) &dummy32->regs.per_info;
/* This is magic. See per_struct and per_struct32. */
if ((offset >= (addr_t) &dummy_per32->control_regs &&
offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
(offset >= (addr_t) &dummy_per32->starting_addr &&
offset <= (addr_t) &dummy_per32->ending_addr) ||
offset == (addr_t) &dummy_per32->lowcore.words.address)
offset = offset*2 + 4;
else
offset = offset*2;
tmp = *(__u32 *)((addr_t) &child->thread.per_info + offset);
} else
tmp = 0;
return put_user(tmp, (__u32 __user *) data);
}
/*
* Same as poke_user but for a 31 bit program.
*/
static int
poke_user_emu31(struct task_struct *child, addr_t addr, addr_t data)
{
struct user32 *dummy32 = NULL;
per_struct32 *dummy_per32 = NULL;
addr_t offset;
__u32 tmp;
if (!test_thread_flag(TIF_31BIT) ||
(addr & 3) || addr > sizeof(struct user32) - 3)
return -EIO;
tmp = (__u32) data;
if (addr < (addr_t) &dummy32->regs.acrs) {
/*
* psw, gprs, acrs and orig_gpr2 are stored on the stack
*/
if (addr == (addr_t) &dummy32->regs.psw.mask) {
/* Build a 64 bit psw mask from 31 bit mask. */
if (tmp != PSW32_MASK_MERGE(psw32_user_bits, tmp))
/* Invalid psw mask. */
return -EINVAL;
task_pt_regs(child)->psw.mask =
PSW_MASK_MERGE(psw_user32_bits, (__u64) tmp << 32);
} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
/* Build a 64 bit psw address from 31 bit address. */
task_pt_regs(child)->psw.addr =
(__u64) tmp & PSW32_ADDR_INSN;
} else {
/* gpr 0-15 */
*(__u32*)((addr_t) &task_pt_regs(child)->psw
+ addr*2 + 4) = tmp;
}
} else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
/*
* access registers are stored in the thread structure
*/
offset = addr - (addr_t) &dummy32->regs.acrs;
*(__u32*)((addr_t) &child->thread.acrs + offset) = tmp;
} else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
/*
* orig_gpr2 is stored on the kernel stack
*/
*(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4) = tmp;
} else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
/*
* floating point regs. are stored in the thread structure
*/
if (addr == (addr_t) &dummy32->regs.fp_regs.fpc &&
(tmp & ~FPC_VALID_MASK) != 0)
/* Invalid floating point control. */
return -EINVAL;
offset = addr - (addr_t) &dummy32->regs.fp_regs;
*(__u32 *)((addr_t) &child->thread.fp_regs + offset) = tmp;
} else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
/*
* per_info is found in the thread structure.
*/
offset = addr - (addr_t) &dummy32->regs.per_info;
/*
* This is magic. See per_struct and per_struct32.
* By incident the offsets in per_struct are exactly
* twice the offsets in per_struct32 for all fields.
* The 8 byte fields need special handling though,
* because the second half (bytes 4-7) is needed and
* not the first half.
*/
if ((offset >= (addr_t) &dummy_per32->control_regs &&
offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
(offset >= (addr_t) &dummy_per32->starting_addr &&
offset <= (addr_t) &dummy_per32->ending_addr) ||
offset == (addr_t) &dummy_per32->lowcore.words.address)
offset = offset*2 + 4;
else
offset = offset*2;
*(__u32 *)((addr_t) &child->thread.per_info + offset) = tmp;
}
FixPerRegisters(child);
return 0;
}
static int
do_ptrace_emu31(struct task_struct *child, long request, long addr, long data)
{
unsigned int tmp; /* 4 bytes !! */
ptrace_area_emu31 parea;
int copied, ret;
switch (request) {
case PTRACE_PEEKTEXT:
case PTRACE_PEEKDATA:
/* read word at location addr. */
copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
if (copied != sizeof(tmp))
return -EIO;
return put_user(tmp, (unsigned int __force __user *) data);
case PTRACE_PEEKUSR:
/* read the word at location addr in the USER area. */
return peek_user_emu31(child, addr, data);
case PTRACE_POKETEXT:
case PTRACE_POKEDATA:
/* write the word at location addr. */
tmp = data;
copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 1);
if (copied != sizeof(tmp))
return -EIO;
return 0;
case PTRACE_POKEUSR:
/* write the word at location addr in the USER area */
return poke_user_emu31(child, addr, data);
case PTRACE_PEEKUSR_AREA:
case PTRACE_POKEUSR_AREA:
if (copy_from_user(&parea, (void __force __user *) addr,
sizeof(parea)))
return -EFAULT;
addr = parea.kernel_addr;
data = parea.process_addr;
copied = 0;
while (copied < parea.len) {
if (request == PTRACE_PEEKUSR_AREA)
ret = peek_user_emu31(child, addr, data);
else {
__u32 utmp;
if (get_user(utmp,
(__u32 __force __user *) data))
return -EFAULT;
ret = poke_user_emu31(child, addr, utmp);
}
if (ret)
return ret;
addr += sizeof(unsigned int);
data += sizeof(unsigned int);
copied += sizeof(unsigned int);
}
return 0;
case PTRACE_GETEVENTMSG:
return put_user((__u32) child->ptrace_message,
(unsigned int __force __user *) data);
case PTRACE_GETSIGINFO:
if (child->last_siginfo == NULL)
return -EINVAL;
return copy_siginfo_to_user32((compat_siginfo_t
__force __user *) data,
child->last_siginfo);
case PTRACE_SETSIGINFO:
if (child->last_siginfo == NULL)
return -EINVAL;
return copy_siginfo_from_user32(child->last_siginfo,
(compat_siginfo_t
__force __user *) data);
}
return ptrace_request(child, request, addr, data);
}
#endif
#define PT32_IEEE_IP 0x13c
static int
do_ptrace(struct task_struct *child, long request, long addr, long data)
{
int ret;
if (request == PTRACE_ATTACH)
return ptrace_attach(child);
/*
* Special cases to get/store the ieee instructions pointer.
*/
if (child == current) {
if (request == PTRACE_PEEKUSR && addr == PT_IEEE_IP)
return peek_user(child, addr, data);
if (request == PTRACE_POKEUSR && addr == PT_IEEE_IP)
return poke_user(child, addr, data);
#ifdef CONFIG_COMPAT
if (request == PTRACE_PEEKUSR &&
addr == PT32_IEEE_IP && test_thread_flag(TIF_31BIT))
return peek_user_emu31(child, addr, data);
if (request == PTRACE_POKEUSR &&
addr == PT32_IEEE_IP && test_thread_flag(TIF_31BIT))
return poke_user_emu31(child, addr, data);
#endif
}
ret = ptrace_check_attach(child, request == PTRACE_KILL);
if (ret < 0)
return ret;
switch (request) {
case PTRACE_SYSCALL:
/* continue and stop at next (return from) syscall */
case PTRACE_CONT:
/* restart after signal. */
if (!valid_signal(data))
return -EIO;
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);
return 0;
case PTRACE_KILL:
/*
* 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.
*/
if (child->exit_state == EXIT_ZOMBIE) /* already dead */
return 0;
child->exit_code = SIGKILL;
/* make sure the single step bit is not set. */
clear_single_step(child);
wake_up_process(child);
return 0;
case PTRACE_SINGLESTEP:
/* set the trap flag. */
if (!valid_signal(data))
return -EIO;
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
child->exit_code = data;
if (data)
set_tsk_thread_flag(child, TIF_SINGLE_STEP);
else
set_single_step(child);
/* give it a chance to run. */
wake_up_process(child);
return 0;
case PTRACE_DETACH:
/* detach a process that was attached. */
return ptrace_detach(child, data);
/* Do requests that differ for 31/64 bit */
default:
#ifdef CONFIG_COMPAT
if (test_thread_flag(TIF_31BIT))
return do_ptrace_emu31(child, request, addr, data);
#endif
return do_ptrace_normal(child, request, addr, data);
}
/* Not reached. */
return -EIO;
}
asmlinkage long
sys_ptrace(long request, long pid, long addr, long data)
{
struct task_struct *child;
int ret;
lock_kernel();
if (request == PTRACE_TRACEME) {
ret = ptrace_traceme();
goto out;
}
child = ptrace_get_task_struct(pid);
if (IS_ERR(child)) {
ret = PTR_ERR(child);
goto out;
}
ret = do_ptrace(child, request, addr, data);
put_task_struct(child);
out:
unlock_kernel();
return ret;
}
asmlinkage void
syscall_trace(struct pt_regs *regs, int entryexit)
{
if (unlikely(current->audit_context) && entryexit)
audit_syscall_exit(AUDITSC_RESULT(regs->gprs[2]), regs->gprs[2]);
if (!test_thread_flag(TIF_SYSCALL_TRACE))
goto out;
if (!(current->ptrace & PT_PTRACED))
goto out;
ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
? 0x80 : 0));
/*
* If the debuffer has set an invalid system call number,
* we prepare to skip the system call restart handling.
*/
if (!entryexit && regs->gprs[2] >= NR_syscalls)
regs->trap = -1;
/*
* 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;
}
out:
if (unlikely(current->audit_context) && !entryexit)
audit_syscall_entry(test_thread_flag(TIF_31BIT)?AUDIT_ARCH_S390:AUDIT_ARCH_S390X,
regs->gprs[2], regs->orig_gpr2, regs->gprs[3],
regs->gprs[4], regs->gprs[5]);
}
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