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/*
* Optimized user space space access functions based on mvcos.
*
* Copyright IBM Corp. 2006
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
* Gerald Schaefer (gerald.schaefer@de.ibm.com)
*/
#include <linux/jump_label.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <asm/facility.h>
#include <asm/uaccess.h>
#include <asm/futex.h>
#include "uaccess.h"
#ifndef CONFIG_64BIT
#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 struct static_key have_mvcos = STATIC_KEY_INIT_TRUE;
static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr,
unsigned long size)
{
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"
"9: 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"
"10:"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) EX_TABLE(9b,2b) EX_TABLE(10b,4b)
: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
: "d" (reg0) : "cc", "memory");
return size;
}
unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
{
if (static_key_true(&have_mvcos))
return copy_from_user_mvcos(to, from, n);
return copy_from_user_pt(to, from, n);
}
EXPORT_SYMBOL(__copy_from_user);
static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x,
unsigned long size)
{
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"
"6: 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"
"7:"SLR" %0,%4\n"
" j 5f\n"
"4:"SLR" %0,%0\n"
"5: \n"
EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
: "d" (reg0) : "cc", "memory");
return size;
}
unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
{
if (static_key_true(&have_mvcos))
return copy_to_user_mvcos(to, from, n);
return copy_to_user_pt(to, from, n);
}
EXPORT_SYMBOL(__copy_to_user);
static inline unsigned long copy_in_user_mvcos(void __user *to, const void __user *from,
unsigned long size)
{
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;
}
unsigned long __copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
if (static_key_true(&have_mvcos))
return copy_in_user_mvcos(to, from, n);
return copy_in_user_pt(to, from, n);
}
EXPORT_SYMBOL(__copy_in_user);
static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size)
{
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;
}
unsigned long __clear_user(void __user *to, unsigned long size)
{
if (static_key_true(&have_mvcos))
return clear_user_mvcos(to, size);
return clear_user_pt(to, size);
}
EXPORT_SYMBOL(__clear_user);
static inline unsigned long strnlen_user_mvcos(const char __user *src,
unsigned long count)
{
unsigned long done, len, offset, len_str;
char buf[256];
done = 0;
do {
offset = (unsigned long)src & ~PAGE_MASK;
len = min(256UL, PAGE_SIZE - offset);
len = min(count - done, len);
if (copy_from_user_mvcos(buf, src, len))
return 0;
len_str = strnlen(buf, len);
done += len_str;
src += len_str;
} while ((len_str == len) && (done < count));
return done + 1;
}
unsigned long __strnlen_user(const char __user *src, unsigned long count)
{
if (static_key_true(&have_mvcos))
return strnlen_user_mvcos(src, count);
return strnlen_user_pt(src, count);
}
EXPORT_SYMBOL(__strnlen_user);
static inline long strncpy_from_user_mvcos(char *dst, const char __user *src,
long count)
{
unsigned long done, len, offset, len_str;
if (unlikely(count <= 0))
return 0;
done = 0;
do {
offset = (unsigned long)src & ~PAGE_MASK;
len = min(count - done, PAGE_SIZE - offset);
if (copy_from_user_mvcos(dst, src, len))
return -EFAULT;
len_str = strnlen(dst, len);
done += len_str;
src += len_str;
dst += len_str;
} while ((len_str == len) && (done < count));
return done;
}
long __strncpy_from_user(char *dst, const char __user *src, long count)
{
if (static_key_true(&have_mvcos))
return strncpy_from_user_mvcos(dst, src, count);
return strncpy_from_user_pt(dst, src, count);
}
EXPORT_SYMBOL(__strncpy_from_user);
/*
* The uaccess page tabe walk variant can be enforced with the "uaccesspt"
* kernel parameter. This is mainly for debugging purposes.
*/
static int force_uaccess_pt __initdata;
static int __init parse_uaccess_pt(char *__unused)
{
force_uaccess_pt = 1;
return 0;
}
early_param("uaccesspt", parse_uaccess_pt);
static int __init uaccess_init(void)
{
if (IS_ENABLED(CONFIG_32BIT) || force_uaccess_pt || !test_facility(27))
static_key_slow_dec(&have_mvcos);
return 0;
}
early_initcall(uaccess_init);
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