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linux/arch/sh/lib/copy_page.S
Paul Mundt a2494b9b5f sh: Kill off dcache writeback from copy_page(). 
Now that the cache purging is handled manually by all copy_page()
callers, we can kill off copy_page()'s on writeback. This optimizes the
non-aliasing case.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-09-08 16:23:08 +09:00

390 lines
6.0 KiB
ArmAsm
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/*
* copy_page, __copy_user_page, __copy_user implementation of SuperH
*
* Copyright (C) 2001 Niibe Yutaka & Kaz Kojima
* Copyright (C) 2002 Toshinobu Sugioka
* Copyright (C) 2006 Paul Mundt
*/
#include <linux/linkage.h>
#include <asm/page.h>
/*
* copy_page
* @to: P1 address
* @from: P1 address
*
* void copy_page(void *to, void *from)
*/
/*
* r0, r1, r2, r3, r4, r5, r6, r7 --- scratch
* r8 --- from + PAGE_SIZE
* r9 --- not used
* r10 --- to
* r11 --- from
*/
ENTRY(copy_page)
mov.l r8,@-r15
mov.l r10,@-r15
mov.l r11,@-r15
mov r4,r10
mov r5,r11
mov r5,r8
mov #(PAGE_SIZE >> 10), r0
shll8 r0
shll2 r0
add r0,r8
!
1: mov.l @r11+,r0
mov.l @r11+,r1
mov.l @r11+,r2
mov.l @r11+,r3
mov.l @r11+,r4
mov.l @r11+,r5
mov.l @r11+,r6
mov.l @r11+,r7
#if defined(CONFIG_CPU_SH4)
movca.l r0,@r10
#else
mov.l r0,@r10
#endif
add #32,r10
mov.l r7,@-r10
mov.l r6,@-r10
mov.l r5,@-r10
mov.l r4,@-r10
mov.l r3,@-r10
mov.l r2,@-r10
mov.l r1,@-r10
cmp/eq r11,r8
bf/s 1b
add #28,r10
!
mov.l @r15+,r11
mov.l @r15+,r10
mov.l @r15+,r8
rts
nop
/*
* __kernel_size_t __copy_user(void *to, const void *from, __kernel_size_t n);
* Return the number of bytes NOT copied
*/
#define EX(...) \
9999: __VA_ARGS__ ; \
.section __ex_table, "a"; \
.long 9999b, 6000f ; \
.previous
#define EX_NO_POP(...) \
9999: __VA_ARGS__ ; \
.section __ex_table, "a"; \
.long 9999b, 6005f ; \
.previous
ENTRY(__copy_user)
! Check if small number of bytes
mov #11,r0
mov r4,r3
cmp/gt r0,r6 ! r6 (len) > r0 (11)
bf/s .L_cleanup_loop_no_pop
add r6,r3 ! last destination address
! Calculate bytes needed to align to src
mov.l r11,@-r15
neg r5,r0
mov.l r10,@-r15
add #4,r0
mov.l r9,@-r15
and #3,r0
mov.l r8,@-r15
tst r0,r0
bt 2f
1:
! Copy bytes to long word align src
EX( mov.b @r5+,r1 )
dt r0
add #-1,r6
EX( mov.b r1,@r4 )
bf/s 1b
add #1,r4
! Jump to appropriate routine depending on dest
2: mov #3,r1
mov r6, r2
and r4,r1
shlr2 r2
shll2 r1
mova .L_jump_tbl,r0
mov.l @(r0,r1),r1
jmp @r1
nop
.align 2
.L_jump_tbl:
.long .L_dest00
.long .L_dest01
.long .L_dest10
.long .L_dest11
/*
* Come here if there are less than 12 bytes to copy
*
* Keep the branch target close, so the bf/s callee doesn't overflow
* and result in a more expensive branch being inserted. This is the
* fast-path for small copies, the jump via the jump table will hit the
* default slow-path cleanup. -PFM.
*/
.L_cleanup_loop_no_pop:
tst r6,r6 ! Check explicitly for zero
bt 1f
2:
EX_NO_POP( mov.b @r5+,r0 )
dt r6
EX_NO_POP( mov.b r0,@r4 )
bf/s 2b
add #1,r4
1: mov #0,r0 ! normal return
5000:
# Exception handler:
.section .fixup, "ax"
6005:
mov.l 8000f,r1
mov r3,r0
jmp @r1
sub r4,r0
.align 2
8000: .long 5000b
.previous
rts
nop
! Destination = 00
.L_dest00:
! Skip the large copy for small transfers
mov #(32+32-4), r0
cmp/gt r6, r0 ! r0 (60) > r6 (len)
bt 1f
! Align dest to a 32 byte boundary
neg r4,r0
add #0x20, r0
and #0x1f, r0
tst r0, r0
bt 2f
sub r0, r6
shlr2 r0
3:
EX( mov.l @r5+,r1 )
dt r0
EX( mov.l r1,@r4 )
bf/s 3b
add #4,r4
2:
EX( mov.l @r5+,r0 )
EX( mov.l @r5+,r1 )
EX( mov.l @r5+,r2 )
EX( mov.l @r5+,r7 )
EX( mov.l @r5+,r8 )
EX( mov.l @r5+,r9 )
EX( mov.l @r5+,r10 )
EX( mov.l @r5+,r11 )
#ifdef CONFIG_CPU_SH4
EX( movca.l r0,@r4 )
#else
EX( mov.l r0,@r4 )
#endif
add #-32, r6
EX( mov.l r1,@(4,r4) )
mov #32, r0
EX( mov.l r2,@(8,r4) )
cmp/gt r6, r0 ! r0 (32) > r6 (len)
EX( mov.l r7,@(12,r4) )
EX( mov.l r8,@(16,r4) )
EX( mov.l r9,@(20,r4) )
EX( mov.l r10,@(24,r4) )
EX( mov.l r11,@(28,r4) )
bf/s 2b
add #32,r4
1: mov r6, r0
shlr2 r0
tst r0, r0
bt .L_cleanup
1:
EX( mov.l @r5+,r1 )
dt r0
EX( mov.l r1,@r4 )
bf/s 1b
add #4,r4
bra .L_cleanup
nop
! Destination = 10
.L_dest10:
mov r2,r7
shlr2 r7
shlr r7
tst r7,r7
mov #7,r0
bt/s 1f
and r0,r2
2:
dt r7
#ifdef CONFIG_CPU_LITTLE_ENDIAN
EX( mov.l @r5+,r0 )
EX( mov.l @r5+,r1 )
EX( mov.l @r5+,r8 )
EX( mov.l @r5+,r9 )
EX( mov.l @r5+,r10 )
EX( mov.w r0,@r4 )
add #2,r4
xtrct r1,r0
xtrct r8,r1
xtrct r9,r8
xtrct r10,r9
EX( mov.l r0,@r4 )
EX( mov.l r1,@(4,r4) )
EX( mov.l r8,@(8,r4) )
EX( mov.l r9,@(12,r4) )
EX( mov.l @r5+,r1 )
EX( mov.l @r5+,r8 )
EX( mov.l @r5+,r0 )
xtrct r1,r10
xtrct r8,r1
xtrct r0,r8
shlr16 r0
EX( mov.l r10,@(16,r4) )
EX( mov.l r1,@(20,r4) )
EX( mov.l r8,@(24,r4) )
EX( mov.w r0,@(28,r4) )
bf/s 2b
add #30,r4
#else
EX( mov.l @(28,r5),r0 )
EX( mov.l @(24,r5),r8 )
EX( mov.l @(20,r5),r9 )
EX( mov.l @(16,r5),r10 )
EX( mov.w r0,@(30,r4) )
add #-2,r4
xtrct r8,r0
xtrct r9,r8
xtrct r10,r9
EX( mov.l r0,@(28,r4) )
EX( mov.l r8,@(24,r4) )
EX( mov.l r9,@(20,r4) )
EX( mov.l @(12,r5),r0 )
EX( mov.l @(8,r5),r8 )
xtrct r0,r10
EX( mov.l @(4,r5),r9 )
mov.l r10,@(16,r4)
EX( mov.l @r5,r10 )
xtrct r8,r0
xtrct r9,r8
xtrct r10,r9
EX( mov.l r0,@(12,r4) )
EX( mov.l r8,@(8,r4) )
swap.w r10,r0
EX( mov.l r9,@(4,r4) )
EX( mov.w r0,@(2,r4) )
add #32,r5
bf/s 2b
add #34,r4
#endif
tst r2,r2
bt .L_cleanup
1: ! Read longword, write two words per iteration
EX( mov.l @r5+,r0 )
dt r2
#ifdef CONFIG_CPU_LITTLE_ENDIAN
EX( mov.w r0,@r4 )
shlr16 r0
EX( mov.w r0,@(2,r4) )
#else
EX( mov.w r0,@(2,r4) )
shlr16 r0
EX( mov.w r0,@r4 )
#endif
bf/s 1b
add #4,r4
bra .L_cleanup
nop
! Destination = 01 or 11
.L_dest01:
.L_dest11:
! Read longword, write byte, word, byte per iteration
EX( mov.l @r5+,r0 )
dt r2
#ifdef CONFIG_CPU_LITTLE_ENDIAN
EX( mov.b r0,@r4 )
shlr8 r0
add #1,r4
EX( mov.w r0,@r4 )
shlr16 r0
EX( mov.b r0,@(2,r4) )
bf/s .L_dest01
add #3,r4
#else
EX( mov.b r0,@(3,r4) )
shlr8 r0
swap.w r0,r7
EX( mov.b r7,@r4 )
add #1,r4
EX( mov.w r0,@r4 )
bf/s .L_dest01
add #3,r4
#endif
! Cleanup last few bytes
.L_cleanup:
mov r6,r0
and #3,r0
tst r0,r0
bt .L_exit
mov r0,r6
.L_cleanup_loop:
EX( mov.b @r5+,r0 )
dt r6
EX( mov.b r0,@r4 )
bf/s .L_cleanup_loop
add #1,r4
.L_exit:
mov #0,r0 ! normal return
5000:
# Exception handler:
.section .fixup, "ax"
6000:
mov.l 8000f,r1
mov r3,r0
jmp @r1
sub r4,r0
.align 2
8000: .long 5000b
.previous
mov.l @r15+,r8
mov.l @r15+,r9
mov.l @r15+,r10
rts
mov.l @r15+,r11
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