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linux_dsm_epyc7002/arch/s390/kernel/ptrace.c
Linus Torvalds ab074ade9c Merge git://git.infradead.org/users/eparis/audit 
Pull audit updates from Eric Paris:
 "So this change across a whole bunch of arches really solves one basic
  problem.  We want to audit when seccomp is killing a process.  seccomp
  hooks in before the audit syscall entry code.  audit_syscall_entry
  took as an argument the arch of the given syscall.  Since the arch is
  part of what makes a syscall number meaningful it's an important part
  of the record, but it isn't available when seccomp shoots the
  syscall...

  For most arch's we have a better way to get the arch (syscall_get_arch)
  So the solution was two fold: Implement syscall_get_arch() everywhere
  there is audit which didn't have it.  Use syscall_get_arch() in the
  seccomp audit code.  Having syscall_get_arch() everywhere meant it was
  a useless flag on the stack and we could get rid of it for the typical
  syscall entry.

  The other changes inside the audit system aren't grand, fixed some
  records that had invalid spaces.  Better locking around the task comm
  field.  Removing some dead functions and structs.  Make some things
  static.  Really minor stuff"

* git://git.infradead.org/users/eparis/audit: (31 commits)
  audit: rename audit_log_remove_rule to disambiguate for trees
  audit: cull redundancy in audit_rule_change
  audit: WARN if audit_rule_change called illegally
  audit: put rule existence check in canonical order
  next: openrisc: Fix build
  audit: get comm using lock to avoid race in string printing
  audit: remove open_arg() function that is never used
  audit: correct AUDIT_GET_FEATURE return message type
  audit: set nlmsg_len for multicast messages.
  audit: use union for audit_field values since they are mutually exclusive
  audit: invalid op= values for rules
  audit: use atomic_t to simplify audit_serial()
  kernel/audit.c: use ARRAY_SIZE instead of sizeof/sizeof[0]
  audit: reduce scope of audit_log_fcaps
  audit: reduce scope of audit_net_id
  audit: arm64: Remove the audit arch argument to audit_syscall_entry
  arm64: audit: Add audit hook in syscall_trace_enter/exit()
  audit: x86: drop arch from __audit_syscall_entry() interface
  sparc: implement is_32bit_task
  sparc: properly conditionalize use of TIF_32BIT
  ...
2014-10-19 16:25:56 -07:00

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/*
* Ptrace user space interface.
*
* Copyright IBM Corp. 1999, 2010
* Author(s): Denis Joseph Barrow
* Martin Schwidefsky (schwidefsky@de.ibm.com)
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.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 <linux/elf.h>
#include <linux/regset.h>
#include <linux/tracehook.h>
#include <linux/seccomp.h>
#include <linux/compat.h>
#include <trace/syscall.h>
#include <asm/segment.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include <asm/switch_to.h>
#include "entry.h"
#ifdef CONFIG_COMPAT
#include "compat_ptrace.h"
#endif
#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>
void update_cr_regs(struct task_struct *task)
{
struct pt_regs *regs = task_pt_regs(task);
struct thread_struct *thread = &task->thread;
struct per_regs old, new;
#ifdef CONFIG_64BIT
/* Take care of the enable/disable of transactional execution. */
if (MACHINE_HAS_TE || MACHINE_HAS_VX) {
unsigned long cr, cr_new;
__ctl_store(cr, 0, 0);
cr_new = cr;
if (MACHINE_HAS_TE) {
/* Set or clear transaction execution TXC bit 8. */
cr_new |= (1UL << 55);
if (task->thread.per_flags & PER_FLAG_NO_TE)
cr_new &= ~(1UL << 55);
}
if (MACHINE_HAS_VX) {
/* Enable/disable of vector extension */
cr_new &= ~(1UL << 17);
if (task->thread.vxrs)
cr_new |= (1UL << 17);
}
if (cr_new != cr)
__ctl_load(cr_new, 0, 0);
if (MACHINE_HAS_TE) {
/* Set/clear transaction execution TDC bits 62/63. */
__ctl_store(cr, 2, 2);
cr_new = cr & ~3UL;
if (task->thread.per_flags & PER_FLAG_TE_ABORT_RAND) {
if (task->thread.per_flags &
PER_FLAG_TE_ABORT_RAND_TEND)
cr_new |= 1UL;
else
cr_new |= 2UL;
}
if (cr_new != cr)
__ctl_load(cr_new, 2, 2);
}
}
#endif
/* Copy user specified PER registers */
new.control = thread->per_user.control;
new.start = thread->per_user.start;
new.end = thread->per_user.end;
/* merge TIF_SINGLE_STEP into user specified PER registers. */
if (test_tsk_thread_flag(task, TIF_SINGLE_STEP) ||
test_tsk_thread_flag(task, TIF_UPROBE_SINGLESTEP)) {
if (test_tsk_thread_flag(task, TIF_BLOCK_STEP))
new.control |= PER_EVENT_BRANCH;
else
new.control |= PER_EVENT_IFETCH;
#ifdef CONFIG_64BIT
new.control |= PER_CONTROL_SUSPENSION;
new.control |= PER_EVENT_TRANSACTION_END;
#endif
if (test_tsk_thread_flag(task, TIF_UPROBE_SINGLESTEP))
new.control |= PER_EVENT_IFETCH;
new.start = 0;
new.end = PSW_ADDR_INSN;
}
/* Take care of the PER enablement bit in the PSW. */
if (!(new.control & PER_EVENT_MASK)) {
regs->psw.mask &= ~PSW_MASK_PER;
return;
}
regs->psw.mask |= PSW_MASK_PER;
__ctl_store(old, 9, 11);
if (memcmp(&new, &old, sizeof(struct per_regs)) != 0)
__ctl_load(new, 9, 11);
}
void user_enable_single_step(struct task_struct *task)
{
clear_tsk_thread_flag(task, TIF_BLOCK_STEP);
set_tsk_thread_flag(task, TIF_SINGLE_STEP);
}
void user_disable_single_step(struct task_struct *task)
{
clear_tsk_thread_flag(task, TIF_BLOCK_STEP);
clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
}
void user_enable_block_step(struct task_struct *task)
{
set_tsk_thread_flag(task, TIF_SINGLE_STEP);
set_tsk_thread_flag(task, TIF_BLOCK_STEP);
}
/*
* Called by kernel/ptrace.c when detaching..
*
* Clear all debugging related fields.
*/
void ptrace_disable(struct task_struct *task)
{
memset(&task->thread.per_user, 0, sizeof(task->thread.per_user));
memset(&task->thread.per_event, 0, sizeof(task->thread.per_event));
clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
clear_pt_regs_flag(task_pt_regs(task), PIF_PER_TRAP);
task->thread.per_flags = 0;
}
#ifndef CONFIG_64BIT
# define __ADDR_MASK 3
#else
# define __ADDR_MASK 7
#endif
static inline unsigned long __peek_user_per(struct task_struct *child,
addr_t addr)
{
struct per_struct_kernel *dummy = NULL;
if (addr == (addr_t) &dummy->cr9)
/* Control bits of the active per set. */
return test_thread_flag(TIF_SINGLE_STEP) ?
PER_EVENT_IFETCH : child->thread.per_user.control;
else if (addr == (addr_t) &dummy->cr10)
/* Start address of the active per set. */
return test_thread_flag(TIF_SINGLE_STEP) ?
0 : child->thread.per_user.start;
else if (addr == (addr_t) &dummy->cr11)
/* End address of the active per set. */
return test_thread_flag(TIF_SINGLE_STEP) ?
PSW_ADDR_INSN : child->thread.per_user.end;
else if (addr == (addr_t) &dummy->bits)
/* Single-step bit. */
return test_thread_flag(TIF_SINGLE_STEP) ?
(1UL << (BITS_PER_LONG - 1)) : 0;
else if (addr == (addr_t) &dummy->starting_addr)
/* Start address of the user specified per set. */
return child->thread.per_user.start;
else if (addr == (addr_t) &dummy->ending_addr)
/* End address of the user specified per set. */
return child->thread.per_user.end;
else if (addr == (addr_t) &dummy->perc_atmid)
/* PER code, ATMID and AI of the last PER trap */
return (unsigned long)
child->thread.per_event.cause << (BITS_PER_LONG - 16);
else if (addr == (addr_t) &dummy->address)
/* Address of the last PER trap */
return child->thread.per_event.address;
else if (addr == (addr_t) &dummy->access_id)
/* Access id of the last PER trap */
return (unsigned long)
child->thread.per_event.paid << (BITS_PER_LONG - 8);
return 0;
}
/*
* 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 unsigned long __peek_user(struct task_struct *child, addr_t addr)
{
struct user *dummy = NULL;
addr_t offset, tmp;
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) {
/* Return a clean psw mask. */
tmp &= PSW_MASK_USER | PSW_MASK_RI;
tmp |= PSW_USER_BITS;
}
} 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) {
/*
* prevent reads of padding hole between
* orig_gpr2 and fp_regs on s390.
*/
tmp = 0;
} 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 <<= BITS_PER_LONG - 32;
} else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
/*
* Handle access to the per_info structure.
*/
addr -= (addr_t) &dummy->regs.per_info;
tmp = __peek_user_per(child, addr);
} else
tmp = 0;
return tmp;
}
static int
peek_user(struct task_struct *child, addr_t addr, addr_t data)
{
addr_t 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) &((struct user *) NULL)->regs.acrs &&
addr < (addr_t) &((struct user *) NULL)->regs.orig_gpr2)
mask = 3;
#endif
if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
return -EIO;
tmp = __peek_user(child, addr);
return put_user(tmp, (addr_t __user *) data);
}
static inline void __poke_user_per(struct task_struct *child,
addr_t addr, addr_t data)
{
struct per_struct_kernel *dummy = NULL;
/*
* There are only three fields in the per_info struct that the
* debugger user can write to.
* 1) cr9: the debugger wants to set a new PER event mask
* 2) starting_addr: the debugger wants to set a new starting
* address to use with the PER event mask.
* 3) ending_addr: the debugger wants to set a new ending
* address to use with the PER event mask.
* The user specified PER event mask and the start and end
* addresses are used only if single stepping is not in effect.
* Writes to any other field in per_info are ignored.
*/
if (addr == (addr_t) &dummy->cr9)
/* PER event mask of the user specified per set. */
child->thread.per_user.control =
data & (PER_EVENT_MASK | PER_CONTROL_MASK);
else if (addr == (addr_t) &dummy->starting_addr)
/* Starting address of the user specified per set. */
child->thread.per_user.start = data;
else if (addr == (addr_t) &dummy->ending_addr)
/* Ending address of the user specified per set. */
child->thread.per_user.end = 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;
if (addr < (addr_t) &dummy->regs.acrs) {
/*
* psw and gprs are stored on the stack
*/
if (addr == (addr_t) &dummy->regs.psw.mask) {
unsigned long mask = PSW_MASK_USER;
mask |= is_ri_task(child) ? PSW_MASK_RI : 0;
if ((data ^ PSW_USER_BITS) & ~mask)
/* Invalid psw mask. */
return -EINVAL;
if ((data & PSW_MASK_ASC) == PSW_ASC_HOME)
/* Invalid address-space-control bits */
return -EINVAL;
if ((data & PSW_MASK_EA) && !(data & PSW_MASK_BA))
/* Invalid addressing mode bits */
return -EINVAL;
}
*(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) {
/*
* prevent writes of padding hole between
* orig_gpr2 and fp_regs on s390.
*/
return 0;
} 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)
if ((unsigned int) data != 0 ||
test_fp_ctl(data >> (BITS_PER_LONG - 32)))
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)) {
/*
* Handle access to the per_info structure.
*/
addr -= (addr_t) &dummy->regs.per_info;
__poke_user_per(child, addr, data);
}
return 0;
}
static int poke_user(struct task_struct *child, addr_t addr, addr_t data)
{
addr_t 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) &((struct user *) NULL)->regs.acrs &&
addr < (addr_t) &((struct user *) NULL)->regs.orig_gpr2)
mask = 3;
#endif
if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
return -EIO;
return __poke_user(child, addr, data);
}
long arch_ptrace(struct task_struct *child, long request,
unsigned long addr, unsigned long data)
{
ptrace_area parea;
int copied, ret;
switch (request) {
case PTRACE_PEEKUSR:
/* read the word at location addr in the USER area. */
return peek_user(child, addr, data);
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;
case PTRACE_GET_LAST_BREAK:
put_user(task_thread_info(child)->last_break,
(unsigned long __user *) data);
return 0;
case PTRACE_ENABLE_TE:
if (!MACHINE_HAS_TE)
return -EIO;
child->thread.per_flags &= ~PER_FLAG_NO_TE;
return 0;
case PTRACE_DISABLE_TE:
if (!MACHINE_HAS_TE)
return -EIO;
child->thread.per_flags |= PER_FLAG_NO_TE;
child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND;
return 0;
case PTRACE_TE_ABORT_RAND:
if (!MACHINE_HAS_TE || (child->thread.per_flags & PER_FLAG_NO_TE))
return -EIO;
switch (data) {
case 0UL:
child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND;
break;
case 1UL:
child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND;
child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND_TEND;
break;
case 2UL:
child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND;
child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND_TEND;
break;
default:
return -EINVAL;
}
return 0;
default:
/* Removing high order bit from addr (only for 31 bit). */
addr &= PSW_ADDR_INSN;
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_per but for a 31 bit program.
*/
static inline __u32 __peek_user_per_compat(struct task_struct *child,
addr_t addr)
{
struct compat_per_struct_kernel *dummy32 = NULL;
if (addr == (addr_t) &dummy32->cr9)
/* Control bits of the active per set. */
return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
PER_EVENT_IFETCH : child->thread.per_user.control;
else if (addr == (addr_t) &dummy32->cr10)
/* Start address of the active per set. */
return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
0 : child->thread.per_user.start;
else if (addr == (addr_t) &dummy32->cr11)
/* End address of the active per set. */
return test_thread_flag(TIF_SINGLE_STEP) ?
PSW32_ADDR_INSN : child->thread.per_user.end;
else if (addr == (addr_t) &dummy32->bits)
/* Single-step bit. */
return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
0x80000000 : 0;
else if (addr == (addr_t) &dummy32->starting_addr)
/* Start address of the user specified per set. */
return (__u32) child->thread.per_user.start;
else if (addr == (addr_t) &dummy32->ending_addr)
/* End address of the user specified per set. */
return (__u32) child->thread.per_user.end;
else if (addr == (addr_t) &dummy32->perc_atmid)
/* PER code, ATMID and AI of the last PER trap */
return (__u32) child->thread.per_event.cause << 16;
else if (addr == (addr_t) &dummy32->address)
/* Address of the last PER trap */
return (__u32) child->thread.per_event.address;
else if (addr == (addr_t) &dummy32->access_id)
/* Access id of the last PER trap */
return (__u32) child->thread.per_event.paid << 24;
return 0;
}
/*
* Same as peek_user but for a 31 bit program.
*/
static u32 __peek_user_compat(struct task_struct *child, addr_t addr)
{
struct compat_user *dummy32 = NULL;
addr_t offset;
__u32 tmp;
if (addr < (addr_t) &dummy32->regs.acrs) {
struct pt_regs *regs = task_pt_regs(child);
/*
* psw and gprs are stored on the stack
*/
if (addr == (addr_t) &dummy32->regs.psw.mask) {
/* Fake a 31 bit psw mask. */
tmp = (__u32)(regs->psw.mask >> 32);
tmp &= PSW32_MASK_USER | PSW32_MASK_RI;
tmp |= PSW32_USER_BITS;
} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
/* Fake a 31 bit psw address. */
tmp = (__u32) regs->psw.addr |
(__u32)(regs->psw.mask & PSW_MASK_BA);
} else {
/* gpr 0-15 */
tmp = *(__u32 *)((addr_t) &regs->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) {
/*
* prevent reads of padding hole between
* orig_gpr2 and fp_regs on s390.
*/
tmp = 0;
} 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)) {
/*
* Handle access to the per_info structure.
*/
addr -= (addr_t) &dummy32->regs.per_info;
tmp = __peek_user_per_compat(child, addr);
} else
tmp = 0;
return tmp;
}
static int peek_user_compat(struct task_struct *child,
addr_t addr, addr_t data)
{
__u32 tmp;
if (!is_compat_task() || (addr & 3) || addr > sizeof(struct user) - 3)
return -EIO;
tmp = __peek_user_compat(child, addr);
return put_user(tmp, (__u32 __user *) data);
}
/*
* Same as poke_user_per but for a 31 bit program.
*/
static inline void __poke_user_per_compat(struct task_struct *child,
addr_t addr, __u32 data)
{
struct compat_per_struct_kernel *dummy32 = NULL;
if (addr == (addr_t) &dummy32->cr9)
/* PER event mask of the user specified per set. */
child->thread.per_user.control =
data & (PER_EVENT_MASK | PER_CONTROL_MASK);
else if (addr == (addr_t) &dummy32->starting_addr)
/* Starting address of the user specified per set. */
child->thread.per_user.start = data;
else if (addr == (addr_t) &dummy32->ending_addr)
/* Ending address of the user specified per set. */
child->thread.per_user.end = data;
}
/*
* Same as poke_user but for a 31 bit program.
*/
static int __poke_user_compat(struct task_struct *child,
addr_t addr, addr_t data)
{
struct compat_user *dummy32 = NULL;
__u32 tmp = (__u32) data;
addr_t offset;
if (addr < (addr_t) &dummy32->regs.acrs) {
struct pt_regs *regs = task_pt_regs(child);
/*
* psw, gprs, acrs and orig_gpr2 are stored on the stack
*/
if (addr == (addr_t) &dummy32->regs.psw.mask) {
__u32 mask = PSW32_MASK_USER;
mask |= is_ri_task(child) ? PSW32_MASK_RI : 0;
/* Build a 64 bit psw mask from 31 bit mask. */
if ((tmp ^ PSW32_USER_BITS) & ~mask)
/* Invalid psw mask. */
return -EINVAL;
if ((data & PSW32_MASK_ASC) == PSW32_ASC_HOME)
/* Invalid address-space-control bits */
return -EINVAL;
regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
(regs->psw.mask & PSW_MASK_BA) |
(__u64)(tmp & mask) << 32;
} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
/* Build a 64 bit psw address from 31 bit address. */
regs->psw.addr = (__u64) tmp & PSW32_ADDR_INSN;
/* Transfer 31 bit amode bit to psw mask. */
regs->psw.mask = (regs->psw.mask & ~PSW_MASK_BA) |
(__u64)(tmp & PSW32_ADDR_AMODE);
} else {
/* gpr 0-15 */
*(__u32*)((addr_t) &regs->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) {
/*
* prevent writess of padding hole between
* orig_gpr2 and fp_regs on s390.
*/
return 0;
} 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 &&
test_fp_ctl(tmp))
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)) {
/*
* Handle access to the per_info structure.
*/
addr -= (addr_t) &dummy32->regs.per_info;
__poke_user_per_compat(child, addr, data);
}
return 0;
}
static int poke_user_compat(struct task_struct *child,
addr_t addr, addr_t data)
{
if (!is_compat_task() || (addr & 3) ||
addr > sizeof(struct compat_user) - 3)
return -EIO;
return __poke_user_compat(child, addr, data);
}
long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
compat_ulong_t caddr, compat_ulong_t cdata)
{
unsigned long addr = caddr;
unsigned long data = cdata;
compat_ptrace_area parea;
int copied, ret;
switch (request) {
case PTRACE_PEEKUSR:
/* read the word at location addr in the USER area. */
return peek_user_compat(child, addr, data);
case PTRACE_POKEUSR:
/* write the word at location addr in the USER area */
return poke_user_compat(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_compat(child, addr, data);
else {
__u32 utmp;
if (get_user(utmp,
(__u32 __force __user *) data))
return -EFAULT;
ret = poke_user_compat(child, addr, utmp);
}
if (ret)
return ret;
addr += sizeof(unsigned int);
data += sizeof(unsigned int);
copied += sizeof(unsigned int);
}
return 0;
case PTRACE_GET_LAST_BREAK:
put_user(task_thread_info(child)->last_break,
(unsigned int __user *) data);
return 0;
}
return compat_ptrace_request(child, request, addr, data);
}
#endif
asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
{
long ret = 0;
/* Do the secure computing check first. */
if (secure_computing()) {
/* seccomp failures shouldn't expose any additional code. */
ret = -1;
goto out;
}
/*
* The sysc_tracesys code in entry.S stored the system
* call number to gprs[2].
*/
if (test_thread_flag(TIF_SYSCALL_TRACE) &&
(tracehook_report_syscall_entry(regs) ||
regs->gprs[2] >= NR_syscalls)) {
/*
* Tracing decided this syscall should not happen or the
* debugger stored an invalid system call number. Skip
* the system call and the system call restart handling.
*/
clear_pt_regs_flag(regs, PIF_SYSCALL);
ret = -1;
}
if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
trace_sys_enter(regs, regs->gprs[2]);
audit_syscall_entry(regs->gprs[2], regs->orig_gpr2,
regs->gprs[3], regs->gprs[4],
regs->gprs[5]);
out:
return ret ?: regs->gprs[2];
}
asmlinkage void do_syscall_trace_exit(struct pt_regs *regs)
{
audit_syscall_exit(regs);
if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
trace_sys_exit(regs, regs->gprs[2]);
if (test_thread_flag(TIF_SYSCALL_TRACE))
tracehook_report_syscall_exit(regs, 0);
}
/*
* user_regset definitions.
*/
static int s390_regs_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
if (target == current)
save_access_regs(target->thread.acrs);
if (kbuf) {
unsigned long *k = kbuf;
while (count > 0) {
*k++ = __peek_user(target, pos);
count -= sizeof(*k);
pos += sizeof(*k);
}
} else {
unsigned long __user *u = ubuf;
while (count > 0) {
if (__put_user(__peek_user(target, pos), u++))
return -EFAULT;
count -= sizeof(*u);
pos += sizeof(*u);
}
}
return 0;
}
static int s390_regs_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
int rc = 0;
if (target == current)
save_access_regs(target->thread.acrs);
if (kbuf) {
const unsigned long *k = kbuf;
while (count > 0 && !rc) {
rc = __poke_user(target, pos, *k++);
count -= sizeof(*k);
pos += sizeof(*k);
}
} else {
const unsigned long __user *u = ubuf;
while (count > 0 && !rc) {
unsigned long word;
rc = __get_user(word, u++);
if (rc)
break;
rc = __poke_user(target, pos, word);
count -= sizeof(*u);
pos += sizeof(*u);
}
}
if (rc == 0 && target == current)
restore_access_regs(target->thread.acrs);
return rc;
}
static int s390_fpregs_get(struct task_struct *target,
const struct user_regset *regset, unsigned int pos,
unsigned int count, void *kbuf, void __user *ubuf)
{
if (target == current) {
save_fp_ctl(&target->thread.fp_regs.fpc);
save_fp_regs(target->thread.fp_regs.fprs);
}
#ifdef CONFIG_64BIT
else if (target->thread.vxrs) {
int i;
for (i = 0; i < __NUM_VXRS_LOW; i++)
target->thread.fp_regs.fprs[i] =
*(freg_t *)(target->thread.vxrs + i);
}
#endif
return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
&target->thread.fp_regs, 0, -1);
}
static int s390_fpregs_set(struct task_struct *target,
const struct user_regset *regset, unsigned int pos,
unsigned int count, const void *kbuf,
const void __user *ubuf)
{
int rc = 0;
if (target == current) {
save_fp_ctl(&target->thread.fp_regs.fpc);
save_fp_regs(target->thread.fp_regs.fprs);
}
/* If setting FPC, must validate it first. */
if (count > 0 && pos < offsetof(s390_fp_regs, fprs)) {
u32 ufpc[2] = { target->thread.fp_regs.fpc, 0 };
rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ufpc,
0, offsetof(s390_fp_regs, fprs));
if (rc)
return rc;
if (ufpc[1] != 0 || test_fp_ctl(ufpc[0]))
return -EINVAL;
target->thread.fp_regs.fpc = ufpc[0];
}
if (rc == 0 && count > 0)
rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
target->thread.fp_regs.fprs,
offsetof(s390_fp_regs, fprs), -1);
if (rc == 0) {
if (target == current) {
restore_fp_ctl(&target->thread.fp_regs.fpc);
restore_fp_regs(target->thread.fp_regs.fprs);
}
#ifdef CONFIG_64BIT
else if (target->thread.vxrs) {
int i;
for (i = 0; i < __NUM_VXRS_LOW; i++)
*(freg_t *)(target->thread.vxrs + i) =
target->thread.fp_regs.fprs[i];
}
#endif
}
return rc;
}
#ifdef CONFIG_64BIT
static int s390_last_break_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
if (count > 0) {
if (kbuf) {
unsigned long *k = kbuf;
*k = task_thread_info(target)->last_break;
} else {
unsigned long __user *u = ubuf;
if (__put_user(task_thread_info(target)->last_break, u))
return -EFAULT;
}
}
return 0;
}
static int s390_last_break_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
return 0;
}
static int s390_tdb_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
struct pt_regs *regs = task_pt_regs(target);
unsigned char *data;
if (!(regs->int_code & 0x200))
return -ENODATA;
data = target->thread.trap_tdb;
return user_regset_copyout(&pos, &count, &kbuf, &ubuf, data, 0, 256);
}
static int s390_tdb_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
return 0;
}
static int s390_vxrs_active(struct task_struct *target,
const struct user_regset *regset)
{
return !!target->thread.vxrs;
}
static int s390_vxrs_low_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
__u64 vxrs[__NUM_VXRS_LOW];
int i;
if (target->thread.vxrs) {
if (target == current)
save_vx_regs(target->thread.vxrs);
for (i = 0; i < __NUM_VXRS_LOW; i++)
vxrs[i] = *((__u64 *)(target->thread.vxrs + i) + 1);
} else
memset(vxrs, 0, sizeof(vxrs));
return user_regset_copyout(&pos, &count, &kbuf, &ubuf, vxrs, 0, -1);
}
static int s390_vxrs_low_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
__u64 vxrs[__NUM_VXRS_LOW];
int i, rc;
if (!target->thread.vxrs) {
rc = alloc_vector_registers(target);
if (rc)
return rc;
} else if (target == current)
save_vx_regs(target->thread.vxrs);
rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, vxrs, 0, -1);
if (rc == 0) {
for (i = 0; i < __NUM_VXRS_LOW; i++)
*((__u64 *)(target->thread.vxrs + i) + 1) = vxrs[i];
if (target == current)
restore_vx_regs(target->thread.vxrs);
}
return rc;
}
static int s390_vxrs_high_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
__vector128 vxrs[__NUM_VXRS_HIGH];
if (target->thread.vxrs) {
if (target == current)
save_vx_regs(target->thread.vxrs);
memcpy(vxrs, target->thread.vxrs + __NUM_VXRS_LOW,
sizeof(vxrs));
} else
memset(vxrs, 0, sizeof(vxrs));
return user_regset_copyout(&pos, &count, &kbuf, &ubuf, vxrs, 0, -1);
}
static int s390_vxrs_high_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
int rc;
if (!target->thread.vxrs) {
rc = alloc_vector_registers(target);
if (rc)
return rc;
} else if (target == current)
save_vx_regs(target->thread.vxrs);
rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
target->thread.vxrs + __NUM_VXRS_LOW, 0, -1);
if (rc == 0 && target == current)
restore_vx_regs(target->thread.vxrs);
return rc;
}
#endif
static int s390_system_call_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
unsigned int *data = &task_thread_info(target)->system_call;
return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
data, 0, sizeof(unsigned int));
}
static int s390_system_call_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
unsigned int *data = &task_thread_info(target)->system_call;
return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
data, 0, sizeof(unsigned int));
}
static const struct user_regset s390_regsets[] = {
{
.core_note_type = NT_PRSTATUS,
.n = sizeof(s390_regs) / sizeof(long),
.size = sizeof(long),
.align = sizeof(long),
.get = s390_regs_get,
.set = s390_regs_set,
},
{
.core_note_type = NT_PRFPREG,
.n = sizeof(s390_fp_regs) / sizeof(long),
.size = sizeof(long),
.align = sizeof(long),
.get = s390_fpregs_get,
.set = s390_fpregs_set,
},
{
.core_note_type = NT_S390_SYSTEM_CALL,
.n = 1,
.size = sizeof(unsigned int),
.align = sizeof(unsigned int),
.get = s390_system_call_get,
.set = s390_system_call_set,
},
#ifdef CONFIG_64BIT
{
.core_note_type = NT_S390_LAST_BREAK,
.n = 1,
.size = sizeof(long),
.align = sizeof(long),
.get = s390_last_break_get,
.set = s390_last_break_set,
},
{
.core_note_type = NT_S390_TDB,
.n = 1,
.size = 256,
.align = 1,
.get = s390_tdb_get,
.set = s390_tdb_set,
},
{
.core_note_type = NT_S390_VXRS_LOW,
.n = __NUM_VXRS_LOW,
.size = sizeof(__u64),
.align = sizeof(__u64),
.active = s390_vxrs_active,
.get = s390_vxrs_low_get,
.set = s390_vxrs_low_set,
},
{
.core_note_type = NT_S390_VXRS_HIGH,
.n = __NUM_VXRS_HIGH,
.size = sizeof(__vector128),
.align = sizeof(__vector128),
.active = s390_vxrs_active,
.get = s390_vxrs_high_get,
.set = s390_vxrs_high_set,
},
#endif
};
static const struct user_regset_view user_s390_view = {
.name = UTS_MACHINE,
.e_machine = EM_S390,
.regsets = s390_regsets,
.n = ARRAY_SIZE(s390_regsets)
};
#ifdef CONFIG_COMPAT
static int s390_compat_regs_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
if (target == current)
save_access_regs(target->thread.acrs);
if (kbuf) {
compat_ulong_t *k = kbuf;
while (count > 0) {
*k++ = __peek_user_compat(target, pos);
count -= sizeof(*k);
pos += sizeof(*k);
}
} else {
compat_ulong_t __user *u = ubuf;
while (count > 0) {
if (__put_user(__peek_user_compat(target, pos), u++))
return -EFAULT;
count -= sizeof(*u);
pos += sizeof(*u);
}
}
return 0;
}
static int s390_compat_regs_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
int rc = 0;
if (target == current)
save_access_regs(target->thread.acrs);
if (kbuf) {
const compat_ulong_t *k = kbuf;
while (count > 0 && !rc) {
rc = __poke_user_compat(target, pos, *k++);
count -= sizeof(*k);
pos += sizeof(*k);
}
} else {
const compat_ulong_t __user *u = ubuf;
while (count > 0 && !rc) {
compat_ulong_t word;
rc = __get_user(word, u++);
if (rc)
break;
rc = __poke_user_compat(target, pos, word);
count -= sizeof(*u);
pos += sizeof(*u);
}
}
if (rc == 0 && target == current)
restore_access_regs(target->thread.acrs);
return rc;
}
static int s390_compat_regs_high_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
compat_ulong_t *gprs_high;
gprs_high = (compat_ulong_t *)
&task_pt_regs(target)->gprs[pos / sizeof(compat_ulong_t)];
if (kbuf) {
compat_ulong_t *k = kbuf;
while (count > 0) {
*k++ = *gprs_high;
gprs_high += 2;
count -= sizeof(*k);
}
} else {
compat_ulong_t __user *u = ubuf;
while (count > 0) {
if (__put_user(*gprs_high, u++))
return -EFAULT;
gprs_high += 2;
count -= sizeof(*u);
}
}
return 0;
}
static int s390_compat_regs_high_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
compat_ulong_t *gprs_high;
int rc = 0;
gprs_high = (compat_ulong_t *)
&task_pt_regs(target)->gprs[pos / sizeof(compat_ulong_t)];
if (kbuf) {
const compat_ulong_t *k = kbuf;
while (count > 0) {
*gprs_high = *k++;
*gprs_high += 2;
count -= sizeof(*k);
}
} else {
const compat_ulong_t __user *u = ubuf;
while (count > 0 && !rc) {
unsigned long word;
rc = __get_user(word, u++);
if (rc)
break;
*gprs_high = word;
*gprs_high += 2;
count -= sizeof(*u);
}
}
return rc;
}
static int s390_compat_last_break_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
compat_ulong_t last_break;
if (count > 0) {
last_break = task_thread_info(target)->last_break;
if (kbuf) {
unsigned long *k = kbuf;
*k = last_break;
} else {
unsigned long __user *u = ubuf;
if (__put_user(last_break, u))
return -EFAULT;
}
}
return 0;
}
static int s390_compat_last_break_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
return 0;
}
static const struct user_regset s390_compat_regsets[] = {
{
.core_note_type = NT_PRSTATUS,
.n = sizeof(s390_compat_regs) / sizeof(compat_long_t),
.size = sizeof(compat_long_t),
.align = sizeof(compat_long_t),
.get = s390_compat_regs_get,
.set = s390_compat_regs_set,
},
{
.core_note_type = NT_PRFPREG,
.n = sizeof(s390_fp_regs) / sizeof(compat_long_t),
.size = sizeof(compat_long_t),
.align = sizeof(compat_long_t),
.get = s390_fpregs_get,
.set = s390_fpregs_set,
},
{
.core_note_type = NT_S390_SYSTEM_CALL,
.n = 1,
.size = sizeof(compat_uint_t),
.align = sizeof(compat_uint_t),
.get = s390_system_call_get,
.set = s390_system_call_set,
},
{
.core_note_type = NT_S390_LAST_BREAK,
.n = 1,
.size = sizeof(long),
.align = sizeof(long),
.get = s390_compat_last_break_get,
.set = s390_compat_last_break_set,
},
{
.core_note_type = NT_S390_TDB,
.n = 1,
.size = 256,
.align = 1,
.get = s390_tdb_get,
.set = s390_tdb_set,
},
{
.core_note_type = NT_S390_VXRS_LOW,
.n = __NUM_VXRS_LOW,
.size = sizeof(__u64),
.align = sizeof(__u64),
.active = s390_vxrs_active,
.get = s390_vxrs_low_get,
.set = s390_vxrs_low_set,
},
{
.core_note_type = NT_S390_VXRS_HIGH,
.n = __NUM_VXRS_HIGH,
.size = sizeof(__vector128),
.align = sizeof(__vector128),
.active = s390_vxrs_active,
.get = s390_vxrs_high_get,
.set = s390_vxrs_high_set,
},
{
.core_note_type = NT_S390_HIGH_GPRS,
.n = sizeof(s390_compat_regs_high) / sizeof(compat_long_t),
.size = sizeof(compat_long_t),
.align = sizeof(compat_long_t),
.get = s390_compat_regs_high_get,
.set = s390_compat_regs_high_set,
},
};
static const struct user_regset_view user_s390_compat_view = {
.name = "s390",
.e_machine = EM_S390,
.regsets = s390_compat_regsets,
.n = ARRAY_SIZE(s390_compat_regsets)
};
#endif
const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
#ifdef CONFIG_COMPAT
if (test_tsk_thread_flag(task, TIF_31BIT))
return &user_s390_compat_view;
#endif
return &user_s390_view;
}
static const char *gpr_names[NUM_GPRS] = {
"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
"r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
};
unsigned long regs_get_register(struct pt_regs *regs, unsigned int offset)
{
if (offset >= NUM_GPRS)
return 0;
return regs->gprs[offset];
}
int regs_query_register_offset(const char *name)
{
unsigned long offset;
if (!name || *name != 'r')
return -EINVAL;
if (kstrtoul(name + 1, 10, &offset))
return -EINVAL;
if (offset >= NUM_GPRS)
return -EINVAL;
return offset;
}
const char *regs_query_register_name(unsigned int offset)
{
if (offset >= NUM_GPRS)
return NULL;
return gpr_names[offset];
}
static int regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
{
unsigned long ksp = kernel_stack_pointer(regs);
return (addr & ~(THREAD_SIZE - 1)) == (ksp & ~(THREAD_SIZE - 1));
}
/**
* regs_get_kernel_stack_nth() - get Nth entry of the stack
* @regs:pt_regs which contains kernel stack pointer.
* @n:stack entry number.
*
* regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
* is specifined by @regs. If the @n th entry is NOT in the kernel stack,
* this returns 0.
*/
unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
{
unsigned long addr;
addr = kernel_stack_pointer(regs) + n * sizeof(long);
if (!regs_within_kernel_stack(regs, addr))
return 0;
return *(unsigned long *)addr;
}
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