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kernel-fxtec-pro1x/arch/s390/lib/uaccess_std.c
Martin Schwidefsky e4d82692f4 [S390] missing sacf in uaccess 
The uaccess functions copy_in_user_std and clear_user_std fail to
switch back from secondary space mode to primary space mode with sacf
in case of an unresolvable page fault. We need to make sure that the
switch back to primary mode is done in all cases, otherwise the code
following the uaccess inline assembly will crash.

Reported-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-01-31 11:30:20 +01:00

317 lines
7.9 KiB
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/*
* arch/s390/lib/uaccess_std.c
*
* Standard user space access functions based on mvcp/mvcs and doing
* interesting things in the secondary space mode.
*
* Copyright (C) IBM Corp. 2006
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
* Gerald Schaefer (gerald.schaefer@de.ibm.com)
*/
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/uaccess.h>
#include <asm/futex.h>
#include "uaccess.h"
#ifndef __s390x__
#define AHI "ahi"
#define ALR "alr"
#define CLR "clr"
#define LHI "lhi"
#define SLR "slr"
#else
#define AHI "aghi"
#define ALR "algr"
#define CLR "clgr"
#define LHI "lghi"
#define SLR "slgr"
#endif
size_t copy_from_user_std(size_t size, const void __user *ptr, void *x)
{
unsigned long tmp1, tmp2;
tmp1 = -256UL;
asm volatile(
"0: mvcp 0(%0,%2),0(%1),%3\n"
"10:jz 8f\n"
"1:"ALR" %0,%3\n"
" la %1,256(%1)\n"
" la %2,256(%2)\n"
"2: mvcp 0(%0,%2),0(%1),%3\n"
"11:jnz 1b\n"
" j 8f\n"
"3: la %4,255(%1)\n" /* %4 = ptr + 255 */
" "LHI" %3,-4096\n"
" nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
" "SLR" %4,%1\n"
" "CLR" %0,%4\n" /* copy crosses next page boundary? */
" jnh 5f\n"
"4: mvcp 0(%4,%2),0(%1),%3\n"
"12:"SLR" %0,%4\n"
" "ALR" %2,%4\n"
"5:"LHI" %4,-1\n"
" "ALR" %4,%0\n" /* copy remaining size, subtract 1 */
" bras %3,7f\n" /* memset loop */
" xc 0(1,%2),0(%2)\n"
"6: xc 0(256,%2),0(%2)\n"
" la %2,256(%2)\n"
"7:"AHI" %4,-256\n"
" jnm 6b\n"
" ex %4,0(%3)\n"
" j 9f\n"
"8:"SLR" %0,%0\n"
"9: \n"
EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,5b)
EX_TABLE(10b,3b) EX_TABLE(11b,3b) EX_TABLE(12b,5b)
: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
: : "cc", "memory");
return size;
}
static size_t copy_from_user_std_check(size_t size, const void __user *ptr,
void *x)
{
if (size <= 1024)
return copy_from_user_std(size, ptr, x);
return copy_from_user_pt(size, ptr, x);
}
size_t copy_to_user_std(size_t size, void __user *ptr, const void *x)
{
unsigned long tmp1, tmp2;
tmp1 = -256UL;
asm volatile(
"0: mvcs 0(%0,%1),0(%2),%3\n"
"7: jz 5f\n"
"1:"ALR" %0,%3\n"
" la %1,256(%1)\n"
" la %2,256(%2)\n"
"2: mvcs 0(%0,%1),0(%2),%3\n"
"8: jnz 1b\n"
" j 5f\n"
"3: la %4,255(%1)\n" /* %4 = ptr + 255 */
" "LHI" %3,-4096\n"
" nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
" "SLR" %4,%1\n"
" "CLR" %0,%4\n" /* copy crosses next page boundary? */
" jnh 6f\n"
"4: mvcs 0(%4,%1),0(%2),%3\n"
"9:"SLR" %0,%4\n"
" j 6f\n"
"5:"SLR" %0,%0\n"
"6: \n"
EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
: : "cc", "memory");
return size;
}
static size_t copy_to_user_std_check(size_t size, void __user *ptr,
const void *x)
{
if (size <= 1024)
return copy_to_user_std(size, ptr, x);
return copy_to_user_pt(size, ptr, x);
}
static size_t copy_in_user_std(size_t size, void __user *to,
const void __user *from)
{
unsigned long tmp1;
asm volatile(
" sacf 256\n"
" "AHI" %0,-1\n"
" jo 5f\n"
" bras %3,3f\n"
"0:"AHI" %0,257\n"
"1: mvc 0(1,%1),0(%2)\n"
" la %1,1(%1)\n"
" la %2,1(%2)\n"
" "AHI" %0,-1\n"
" jnz 1b\n"
" j 5f\n"
"2: mvc 0(256,%1),0(%2)\n"
" la %1,256(%1)\n"
" la %2,256(%2)\n"
"3:"AHI" %0,-256\n"
" jnm 2b\n"
"4: ex %0,1b-0b(%3)\n"
"5: "SLR" %0,%0\n"
"6: sacf 0\n"
EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
: "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
: : "cc", "memory");
return size;
}
static size_t clear_user_std(size_t size, void __user *to)
{
unsigned long tmp1, tmp2;
asm volatile(
" sacf 256\n"
" "AHI" %0,-1\n"
" jo 5f\n"
" bras %3,3f\n"
" xc 0(1,%1),0(%1)\n"
"0:"AHI" %0,257\n"
" la %2,255(%1)\n" /* %2 = ptr + 255 */
" srl %2,12\n"
" sll %2,12\n" /* %2 = (ptr + 255) & -4096 */
" "SLR" %2,%1\n"
" "CLR" %0,%2\n" /* clear crosses next page boundary? */
" jnh 5f\n"
" "AHI" %2,-1\n"
"1: ex %2,0(%3)\n"
" "AHI" %2,1\n"
" "SLR" %0,%2\n"
" j 5f\n"
"2: xc 0(256,%1),0(%1)\n"
" la %1,256(%1)\n"
"3:"AHI" %0,-256\n"
" jnm 2b\n"
"4: ex %0,0(%3)\n"
"5: "SLR" %0,%0\n"
"6: sacf 0\n"
EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
: "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
: : "cc", "memory");
return size;
}
size_t strnlen_user_std(size_t size, const char __user *src)
{
register unsigned long reg0 asm("0") = 0UL;
unsigned long tmp1, tmp2;
asm volatile(
" la %2,0(%1)\n"
" la %3,0(%0,%1)\n"
" "SLR" %0,%0\n"
" sacf 256\n"
"0: srst %3,%2\n"
" jo 0b\n"
" la %0,1(%3)\n" /* strnlen_user results includes \0 */
" "SLR" %0,%1\n"
"1: sacf 0\n"
EX_TABLE(0b,1b)
: "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
: "d" (reg0) : "cc", "memory");
return size;
}
size_t strncpy_from_user_std(size_t size, const char __user *src, char *dst)
{
register unsigned long reg0 asm("0") = 0UL;
unsigned long tmp1, tmp2;
asm volatile(
" la %3,0(%1)\n"
" la %4,0(%0,%1)\n"
" sacf 256\n"
"0: srst %4,%3\n"
" jo 0b\n"
" sacf 0\n"
" la %0,0(%4)\n"
" jh 1f\n" /* found \0 in string ? */
" "AHI" %4,1\n" /* include \0 in copy */
"1:"SLR" %0,%1\n" /* %0 = return length (without \0) */
" "SLR" %4,%1\n" /* %4 = copy length (including \0) */
"2: mvcp 0(%4,%2),0(%1),%5\n"
" jz 9f\n"
"3:"AHI" %4,-256\n"
" la %1,256(%1)\n"
" la %2,256(%2)\n"
"4: mvcp 0(%4,%2),0(%1),%5\n"
" jnz 3b\n"
" j 9f\n"
"7: sacf 0\n"
"8:"LHI" %0,%6\n"
"9:\n"
EX_TABLE(0b,7b) EX_TABLE(2b,8b) EX_TABLE(4b,8b)
: "+a" (size), "+a" (src), "+d" (dst), "=a" (tmp1), "=a" (tmp2)
: "d" (reg0), "K" (-EFAULT) : "cc", "memory");
return size;
}
#define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg) \
asm volatile( \
" sacf 256\n" \
"0: l %1,0(%6)\n" \
"1:"insn \
"2: cs %1,%2,0(%6)\n" \
"3: jl 1b\n" \
" lhi %0,0\n" \
"4: sacf 0\n" \
EX_TABLE(0b,4b) EX_TABLE(2b,4b) EX_TABLE(3b,4b) \
: "=d" (ret), "=&d" (oldval), "=&d" (newval), \
"=m" (*uaddr) \
: "0" (-EFAULT), "d" (oparg), "a" (uaddr), \
"m" (*uaddr) : "cc");
int futex_atomic_op_std(int op, int __user *uaddr, int oparg, int *old)
{
int oldval = 0, newval, ret;
switch (op) {
case FUTEX_OP_SET:
__futex_atomic_op("lr %2,%5\n",
ret, oldval, newval, uaddr, oparg);
break;
case FUTEX_OP_ADD:
__futex_atomic_op("lr %2,%1\nar %2,%5\n",
ret, oldval, newval, uaddr, oparg);
break;
case FUTEX_OP_OR:
__futex_atomic_op("lr %2,%1\nor %2,%5\n",
ret, oldval, newval, uaddr, oparg);
break;
case FUTEX_OP_ANDN:
__futex_atomic_op("lr %2,%1\nnr %2,%5\n",
ret, oldval, newval, uaddr, oparg);
break;
case FUTEX_OP_XOR:
__futex_atomic_op("lr %2,%1\nxr %2,%5\n",
ret, oldval, newval, uaddr, oparg);
break;
default:
ret = -ENOSYS;
}
*old = oldval;
return ret;
}
int futex_atomic_cmpxchg_std(int __user *uaddr, int oldval, int newval)
{
int ret;
asm volatile(
" sacf 256\n"
"0: cs %1,%4,0(%5)\n"
"1: lr %0,%1\n"
"2: sacf 0\n"
EX_TABLE(0b,2b) EX_TABLE(1b,2b)
: "=d" (ret), "+d" (oldval), "=m" (*uaddr)
: "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
: "cc", "memory" );
return ret;
}
struct uaccess_ops uaccess_std = {
.copy_from_user = copy_from_user_std_check,
.copy_from_user_small = copy_from_user_std,
.copy_to_user = copy_to_user_std_check,
.copy_to_user_small = copy_to_user_std,
.copy_in_user = copy_in_user_std,
.clear_user = clear_user_std,
.strnlen_user = strnlen_user_std,
.strncpy_from_user = strncpy_from_user_std,
.futex_atomic_op = futex_atomic_op_std,
.futex_atomic_cmpxchg = futex_atomic_cmpxchg_std,
};
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