alistair23-linux/arch/s390/lib/uaccess.c
Martin Schwidefsky d66bf801e0 s390/uaccess: avoid mvcos jump label
If the kernel is compiled for z10 or later machines the uaccess
code inlines the mvcos instruction. The facility bit 27 which
indicates the availability of MVCOS has to be set. The have_mvcos
jump label will always be true.

Make the generation of the have_mvcos jump label conditional on
!CONFIG_HAVE_MARCH_Z10_FEATURES.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-08-29 16:29:10 +02:00

374 lines
9.4 KiB
C

/*
* Standard user space access functions based on mvcp/mvcs and doing
* interesting things in the secondary space mode.
*
* Copyright IBM Corp. 2006,2014
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
* Gerald Schaefer (gerald.schaefer@de.ibm.com)
*/
#include <linux/jump_label.h>
#include <linux/uaccess.h>
#include <linux/export.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <asm/mmu_context.h>
#include <asm/facility.h>
#ifndef CONFIG_HAVE_MARCH_Z10_FEATURES
static DEFINE_STATIC_KEY_FALSE(have_mvcos);
static int __init uaccess_init(void)
{
if (test_facility(27))
static_branch_enable(&have_mvcos);
return 0;
}
early_initcall(uaccess_init);
static inline int copy_with_mvcos(void)
{
if (static_branch_likely(&have_mvcos))
return 1;
return 0;
}
#else
static inline int copy_with_mvcos(void)
{
return 1;
}
#endif
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"
"6: jz 4f\n"
"1: algr %0,%3\n"
" slgr %1,%3\n"
" slgr %2,%3\n"
" j 0b\n"
"2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
" nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
" slgr %4,%1\n"
" clgr %0,%4\n" /* copy crosses next page boundary? */
" jnh 5f\n"
"3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
"7: slgr %0,%4\n"
" j 5f\n"
"4: slgr %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;
}
static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr,
unsigned long size)
{
unsigned long tmp1, tmp2;
load_kernel_asce();
tmp1 = -256UL;
asm volatile(
" sacf 0\n"
"0: mvcp 0(%0,%2),0(%1),%3\n"
"7: jz 5f\n"
"1: algr %0,%3\n"
" la %1,256(%1)\n"
" la %2,256(%2)\n"
"2: mvcp 0(%0,%2),0(%1),%3\n"
"8: jnz 1b\n"
" j 5f\n"
"3: la %4,255(%1)\n" /* %4 = ptr + 255 */
" lghi %3,-4096\n"
" nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
" slgr %4,%1\n"
" clgr %0,%4\n" /* copy crosses next page boundary? */
" jnh 6f\n"
"4: mvcp 0(%4,%2),0(%1),%3\n"
"9: slgr %0,%4\n"
" j 6f\n"
"5: slgr %0,%0\n"
"6: sacf 768\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;
}
unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
{
if (copy_with_mvcos())
return copy_from_user_mvcos(to, from, n);
return copy_from_user_mvcp(to, from, n);
}
EXPORT_SYMBOL(raw_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: algr %0,%3\n"
" slgr %1,%3\n"
" slgr %2,%3\n"
" j 0b\n"
"2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
" nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
" slgr %4,%1\n"
" clgr %0,%4\n" /* copy crosses next page boundary? */
" jnh 5f\n"
"3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
"7: slgr %0,%4\n"
" j 5f\n"
"4: slgr %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;
}
static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
unsigned long size)
{
unsigned long tmp1, tmp2;
load_kernel_asce();
tmp1 = -256UL;
asm volatile(
" sacf 0\n"
"0: mvcs 0(%0,%1),0(%2),%3\n"
"7: jz 5f\n"
"1: algr %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 */
" lghi %3,-4096\n"
" nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
" slgr %4,%1\n"
" clgr %0,%4\n" /* copy crosses next page boundary? */
" jnh 6f\n"
"4: mvcs 0(%4,%1),0(%2),%3\n"
"9: slgr %0,%4\n"
" j 6f\n"
"5: slgr %0,%0\n"
"6: sacf 768\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;
}
unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
{
if (copy_with_mvcos())
return copy_to_user_mvcos(to, from, n);
return copy_to_user_mvcs(to, from, n);
}
EXPORT_SYMBOL(raw_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: algr %0,%3\n"
" slgr %1,%3\n"
" slgr %2,%3\n"
" j 0b\n"
"2:slgr %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 inline unsigned long copy_in_user_mvc(void __user *to, const void __user *from,
unsigned long size)
{
unsigned long tmp1;
load_kernel_asce();
asm volatile(
" sacf 256\n"
" aghi %0,-1\n"
" jo 5f\n"
" bras %3,3f\n"
"0: aghi %0,257\n"
"1: mvc 0(1,%1),0(%2)\n"
" la %1,1(%1)\n"
" la %2,1(%2)\n"
" aghi %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: aghi %0,-256\n"
" jnm 2b\n"
"4: ex %0,1b-0b(%3)\n"
"5: slgr %0,%0\n"
"6: sacf 768\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;
}
unsigned long raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
if (copy_with_mvcos())
return copy_in_user_mvcos(to, from, n);
return copy_in_user_mvc(to, from, n);
}
EXPORT_SYMBOL(raw_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: algr %0,%2\n"
" slgr %1,%2\n"
" j 0b\n"
"2: la %3,4095(%1)\n"/* %4 = to + 4095 */
" nr %3,%2\n" /* %4 = (to + 4095) & -4096 */
" slgr %3,%1\n"
" clgr %0,%3\n" /* copy crosses next page boundary? */
" jnh 5f\n"
"3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
" slgr %0,%3\n"
" j 5f\n"
"4: slgr %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 inline unsigned long clear_user_xc(void __user *to, unsigned long size)
{
unsigned long tmp1, tmp2;
load_kernel_asce();
asm volatile(
" sacf 256\n"
" aghi %0,-1\n"
" jo 5f\n"
" bras %3,3f\n"
" xc 0(1,%1),0(%1)\n"
"0: aghi %0,257\n"
" la %2,255(%1)\n" /* %2 = ptr + 255 */
" srl %2,12\n"
" sll %2,12\n" /* %2 = (ptr + 255) & -4096 */
" slgr %2,%1\n"
" clgr %0,%2\n" /* clear crosses next page boundary? */
" jnh 5f\n"
" aghi %2,-1\n"
"1: ex %2,0(%3)\n"
" aghi %2,1\n"
" slgr %0,%2\n"
" j 5f\n"
"2: xc 0(256,%1),0(%1)\n"
" la %1,256(%1)\n"
"3: aghi %0,-256\n"
" jnm 2b\n"
"4: ex %0,0(%3)\n"
"5: slgr %0,%0\n"
"6: sacf 768\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;
}
unsigned long __clear_user(void __user *to, unsigned long size)
{
if (copy_with_mvcos())
return clear_user_mvcos(to, size);
return clear_user_xc(to, size);
}
EXPORT_SYMBOL(__clear_user);
static inline unsigned long strnlen_user_srst(const char __user *src,
unsigned long size)
{
register unsigned long reg0 asm("0") = 0;
unsigned long tmp1, tmp2;
asm volatile(
" la %2,0(%1)\n"
" la %3,0(%0,%1)\n"
" slgr %0,%0\n"
" sacf 256\n"
"0: srst %3,%2\n"
" jo 0b\n"
" la %0,1(%3)\n" /* strnlen_user results includes \0 */
" slgr %0,%1\n"
"1: sacf 768\n"
EX_TABLE(0b,1b)
: "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
: "d" (reg0) : "cc", "memory");
return size;
}
unsigned long __strnlen_user(const char __user *src, unsigned long size)
{
if (unlikely(!size))
return 0;
load_kernel_asce();
return strnlen_user_srst(src, size);
}
EXPORT_SYMBOL(__strnlen_user);
long __strncpy_from_user(char *dst, const char __user *src, long size)
{
size_t done, len, offset, len_str;
if (unlikely(size <= 0))
return 0;
done = 0;
do {
offset = (size_t)src & (L1_CACHE_BYTES - 1);
len = min(size - done, L1_CACHE_BYTES - offset);
if (copy_from_user(dst, src, len))
return -EFAULT;
len_str = strnlen(dst, len);
done += len_str;
src += len_str;
dst += len_str;
} while ((len_str == len) && (done < size));
return done;
}
EXPORT_SYMBOL(__strncpy_from_user);