/*
* arch/s390/lib/uaccess_mvcos.c
*
* Optimized user space space access functions based on mvcos.
*
* 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 <asm/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
static size_t copy_from_user_mvcos(size_t size, const void __user *ptr, void *x)
{
register unsigned long reg0 asm("0") = 0x81UL;
unsigned long tmp1, tmp2;
tmp1 = -4096UL;
asm volatile(
"0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
" jz 7f\n"
"1:"ALR" %0,%3\n"
" "SLR" %1,%3\n"
" "SLR" %2,%3\n"
" j 0b\n"
"2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
" nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
" "SLR" %4,%1\n"
" "CLR" %0,%4\n" /* copy crosses next page boundary? */
" jnh 4f\n"
"3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
" "SLR" %0,%4\n"
" "ALR" %2,%4\n"
"4:"LHI" %4,-1\n"
" "ALR" %4,%0\n" /* copy remaining size, subtract 1 */
" bras %3,6f\n" /* memset loop */
" xc 0(1,%2),0(%2)\n"
"5: xc 0(256,%2),0(%2)\n"
" la %2,256(%2)\n"
"6:"AHI" %4,-256\n"
" jnm 5b\n"
" ex %4,0(%3)\n"
" j 8f\n"
"7:"SLR" %0,%0\n"
"8: \n"
EX_TABLE(0b,2b) EX_TABLE(3b,4b)
: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
: "d" (reg0) : "cc", "memory");
return size;
}
static size_t copy_from_user_mvcos_check(size_t size, const void __user *ptr, void *x)
{
if (size <= 256)
return copy_from_user_std(size, ptr, x);
return copy_from_user_mvcos(size, ptr, x);
}
static size_t copy_to_user_mvcos(size_t size, void __user *ptr, const void *x)
{
register unsigned long reg0 asm("0") = 0x810000UL;
unsigned long tmp1, tmp2;
tmp1 = -4096UL;
asm volatile(
"0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
" jz 4f\n"
"1:"ALR" %0,%3\n"
" "SLR" %1,%3\n"
" "SLR" %2,%3\n"
" j 0b\n"
"2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
" nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
" "SLR" %4,%1\n"
" "CLR" %0,%4\n" /* copy crosses next page boundary? */
" jnh 5f\n"
"3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
" "SLR" %0,%4\n"
" j 5f\n"
"4:"SLR" %0,%0\n"
"5: \n"
EX_TABLE(0b,2b) EX_TABLE(3b,5b)
: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
: "d" (reg0) : "cc", "memory");
return size;
}
static size_t copy_to_user_mvcos_check(size_t size, void __user *ptr,
const void *x)
{
if (size <= 256)
return copy_to_user_std(size, ptr, x);
return copy_to_user_mvcos(size, ptr, x);
}
static size_t copy_in_user_mvcos(size_t size, void __user *to,
const void __user *from)
{
register unsigned long reg0 asm("0") = 0x810081UL;
unsigned long tmp1, tmp2;
tmp1 = -4096UL;
/* FIXME: copy with reduced length. */
asm volatile(
"0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
" jz 2f\n"
"1:"ALR" %0,%3\n"
" "SLR" %1,%3\n"
" "SLR" %2,%3\n"
" j 0b\n"
"2:"SLR" %0,%0\n"
"3: \n"
EX_TABLE(0b,3b)
: "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
: "d" (reg0) : "cc", "memory");
return size;
}
static size_t clear_user_mvcos(size_t size, void __user *to)
{
register unsigned long reg0 asm("0") = 0x810000UL;
unsigned long tmp1, tmp2;
tmp1 = -4096UL;
asm volatile(
"0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
" jz 4f\n"
"1:"ALR" %0,%2\n"
" "SLR" %1,%2\n"
" j 0b\n"
"2: la %3,4095(%1)\n"/* %4 = to + 4095 */
" nr %3,%2\n" /* %4 = (to + 4095) & -4096 */
" "SLR" %3,%1\n"
" "CLR" %0,%3\n" /* copy crosses next page boundary? */
" jnh 5f\n"
"3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
" "SLR" %0,%3\n"
" j 5f\n"
"4:"SLR" %0,%0\n"
"5: \n"
EX_TABLE(0b,2b) EX_TABLE(3b,5b)
: "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
: "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
return size;
}
static size_t strnlen_user_mvcos(size_t count, const char __user *src)
{
char buf[256];
int rc;
size_t done, len, len_str;
done = 0;
do {
len = min(count - done, (size_t) 256);
rc = uaccess.copy_from_user(len, src + done, buf);
if (unlikely(rc == len))
return 0;
len -= rc;
len_str = strnlen(buf, len);
done += len_str;
} while ((len_str == len) && (done < count));
return done + 1;
}
static size_t strncpy_from_user_mvcos(size_t count, const char __user *src,
char *dst)
{
int rc;
size_t done, len, len_str;
done = 0;
do {
len = min(count - done, (size_t) 4096);
rc = uaccess.copy_from_user(len, src + done, dst);
if (unlikely(rc == len))
return -EFAULT;
len -= rc;
len_str = strnlen(dst, len);
done += len_str;
} while ((len_str == len) && (done < count));
return done;
}
struct uaccess_ops uaccess_mvcos = {
.copy_from_user = copy_from_user_mvcos_check,
.copy_from_user_small = copy_from_user_std,
.copy_to_user = copy_to_user_mvcos_check,
.copy_to_user_small = copy_to_user_std,
.copy_in_user = copy_in_user_mvcos,
.clear_user = clear_user_mvcos,
.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,
};
#ifdef CONFIG_S390_SWITCH_AMODE
struct uaccess_ops uaccess_mvcos_switch = {
.copy_from_user = copy_from_user_mvcos,
.copy_from_user_small = copy_from_user_mvcos,
.copy_to_user = copy_to_user_mvcos,
.copy_to_user_small = copy_to_user_mvcos,
.copy_in_user = copy_in_user_mvcos,
.clear_user = clear_user_mvcos,
.strnlen_user = strnlen_user_mvcos,
.strncpy_from_user = strncpy_from_user_mvcos,
.futex_atomic_op = futex_atomic_op_pt,
.futex_atomic_cmpxchg = futex_atomic_cmpxchg_pt,
};
#endif
