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linux/arch/s390/kernel/ptrace.c

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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>
#ifdef CONFIG_S390_SUPPORT
#include "compat_ptrace.h"
#endif
static void
FixPerRegisters(struct task_struct *task)
{
struct pt_regs *regs;
per_struct *per_info;
regs = __KSTK_PTREGS(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_S390_SUPPORT
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;
}
void
set_single_step(struct task_struct *task)
{
task->thread.per_info.single_step = 1;
FixPerRegisters(task);
}
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_ARCH_S390X
# 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;
/*
* Stupid gdb peeks/pokes the access registers in 64 bit with
* an alignment of 4. Programmers from hell...
*/
if ((addr & 3) || 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) &__KSTK_PTREGS(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;
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) __KSTK_PTREGS(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);
} 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;
/*
* Stupid gdb peeks/pokes the access registers in 64 bit with
* an alignment of 4. Programmers from hell indeed...
*/
if ((addr & 3) || 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_S390_SUPPORT
data != PSW_MASK_MERGE(PSW_USER32_BITS, data) &&
#endif
data != PSW_MASK_MERGE(PSW_USER_BITS, data))
/* Invalid psw mask. */
return -EINVAL;
#ifndef CONFIG_ARCH_S390X
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) &__KSTK_PTREGS(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;
*(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
*/
__KSTK_PTREGS(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 & ~FPC_VALID_MASK) != 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 __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 __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 tmp;
if (get_user (tmp, (addr_t __user *) data))
return -EFAULT;
ret = poke_user(child, addr, tmp);
}
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_S390_SUPPORT
/*
* 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)(__KSTK_PTREGS(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) __KSTK_PTREGS(child)->psw.addr |
PSW32_ADDR_AMODE31;
} else {
/* gpr 0-15 */
tmp = *(__u32 *)((addr_t) &__KSTK_PTREGS(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) &__KSTK_PTREGS(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;
__KSTK_PTREGS(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. */
__KSTK_PTREGS(child)->psw.addr =
(__u64) tmp & PSW32_ADDR_INSN;
} else {
/* gpr 0-15 */
*(__u32*)((addr_t) &__KSTK_PTREGS(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) &__KSTK_PTREGS(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 __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 __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 tmp;
if (get_user (tmp, (__u32 __user *) data))
return -EFAULT;
ret = poke_user_emu31(child, addr, tmp);
}
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 __user *) data);
case PTRACE_GETSIGINFO:
if (child->last_siginfo == NULL)
return -EINVAL;
return copy_siginfo_to_user32((compat_siginfo_t __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 __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_S390_SUPPORT
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_S390_SUPPORT
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) {
/* are we already being traced? */
ret = -EPERM;
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;
goto out;
}
ret = -EPERM;
if (pid == 1) /* you may not mess with init */
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 = 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(current, 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));
/*
* 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(current,
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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