linux/arch/sparc/lib/copy_in_user.S
David S. Miller 83a17d2661 sparc64: Prepare to move to more saner user copy exception handling.
The fixup helper function mechanism for handling user copy fault
handling is not %100 accurrate, and can never be made so.

We are going to transition the code to return the running return
return length, which is always kept track in one or more registers
of each of these routines.

In order to convert them one by one, we have to allow the existing
behavior to continue functioning.

Therefore make all the copy code that wants the fixup helper to be
used return negative one.

After all of the user copy routines have been converted, this logic
and the fixup helpers themselves can be removed completely.

Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-24 11:31:58 -07:00

95 lines
1.7 KiB
ArmAsm

/* copy_in_user.S: Copy from userspace to userspace.
*
* Copyright (C) 1999, 2000, 2004 David S. Miller (davem@redhat.com)
*/
#include <linux/linkage.h>
#include <asm/asi.h>
#include <asm/export.h>
#define XCC xcc
#define EX(x,y) \
98: x,y; \
.section __ex_table,"a";\
.align 4; \
.word 98b, __retl_mone; \
.text; \
.align 4;
.register %g2,#scratch
.register %g3,#scratch
.text
.align 32
/* Don't try to get too fancy here, just nice and
* simple. This is predominantly used for well aligned
* small copies in the compat layer. It is also used
* to copy register windows around during thread cloning.
*/
ENTRY(___copy_in_user) /* %o0=dst, %o1=src, %o2=len */
cmp %o2, 0
be,pn %XCC, 85f
or %o0, %o1, %o3
cmp %o2, 16
bleu,a,pn %XCC, 80f
or %o3, %o2, %o3
/* 16 < len <= 64 */
andcc %o3, 0x7, %g0
bne,pn %XCC, 90f
nop
andn %o2, 0x7, %o4
and %o2, 0x7, %o2
1: subcc %o4, 0x8, %o4
EX(ldxa [%o1] %asi, %o5)
EX(stxa %o5, [%o0] %asi)
add %o1, 0x8, %o1
bgu,pt %XCC, 1b
add %o0, 0x8, %o0
andcc %o2, 0x4, %g0
be,pt %XCC, 1f
nop
sub %o2, 0x4, %o2
EX(lduwa [%o1] %asi, %o5)
EX(stwa %o5, [%o0] %asi)
add %o1, 0x4, %o1
add %o0, 0x4, %o0
1: cmp %o2, 0
be,pt %XCC, 85f
nop
ba,pt %xcc, 90f
nop
80: /* 0 < len <= 16 */
andcc %o3, 0x3, %g0
bne,pn %XCC, 90f
nop
82:
subcc %o2, 4, %o2
EX(lduwa [%o1] %asi, %g1)
EX(stwa %g1, [%o0] %asi)
add %o1, 4, %o1
bgu,pt %XCC, 82b
add %o0, 4, %o0
85: retl
clr %o0
.align 32
90:
subcc %o2, 1, %o2
EX(lduba [%o1] %asi, %g1)
EX(stba %g1, [%o0] %asi)
add %o1, 1, %o1
bgu,pt %XCC, 90b
add %o0, 1, %o0
retl
clr %o0
ENDPROC(___copy_in_user)
EXPORT_SYMBOL(___copy_in_user)