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linux/arch/sh/lib/__clear_user.S

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sh: Fixup various PAGE_SIZE == 4096 assumptions. There were a number of places that made evil PAGE_SIZE == 4k assumptions that ended up breaking when trying to play with 8k and 64k page sizes, this fixes those up. The most significant change is the way we load THREAD_SIZE, previously this was done via: mov #(THREAD_SIZE >> 8), reg shll8 reg to avoid a memory access and allow the immediate load. With a 64k PAGE_SIZE, we're out of range for the immediate load size without resorting to special instructions available in later ISAs (movi20s and so on). The "workaround" for this is to bump up the shift to 10 and insert a shll2, which gives a bit more flexibility while still being much cheaper than a memory access. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2006-11-27 06:06:26 +03:00
/*
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
* __clear_user_page, __clear_user, clear_page implementation of SuperH
*
* Copyright (C) 2001 Kaz Kojima
* Copyright (C) 2001, 2002 Niibe Yutaka
sh: Fixup various PAGE_SIZE == 4096 assumptions. There were a number of places that made evil PAGE_SIZE == 4k assumptions that ended up breaking when trying to play with 8k and 64k page sizes, this fixes those up. The most significant change is the way we load THREAD_SIZE, previously this was done via: mov #(THREAD_SIZE >> 8), reg shll8 reg to avoid a memory access and allow the immediate load. With a 64k PAGE_SIZE, we're out of range for the immediate load size without resorting to special instructions available in later ISAs (movi20s and so on). The "workaround" for this is to bump up the shift to 10 and insert a shll2, which gives a bit more flexibility while still being much cheaper than a memory access. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2006-11-27 06:06:26 +03:00
* Copyright (C) 2006 Paul Mundt
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
*/
#include <linux/linkage.h>
sh: Fixup various PAGE_SIZE == 4096 assumptions. There were a number of places that made evil PAGE_SIZE == 4k assumptions that ended up breaking when trying to play with 8k and 64k page sizes, this fixes those up. The most significant change is the way we load THREAD_SIZE, previously this was done via: mov #(THREAD_SIZE >> 8), reg shll8 reg to avoid a memory access and allow the immediate load. With a 64k PAGE_SIZE, we're out of range for the immediate load size without resorting to special instructions available in later ISAs (movi20s and so on). The "workaround" for this is to bump up the shift to 10 and insert a shll2, which gives a bit more flexibility while still being much cheaper than a memory access. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2006-11-27 06:06:26 +03:00
#include <asm/page.h>
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
ENTRY(__clear_user)
!
mov #0, r0
sh: Remove implicit sign extension from assembler immediates The SH instruction set has several instructions which accept an 8 bit immediate operand. For logical instructions this operand is zero extended, for arithmetic instructions the operand is sign extended. After adding an option to the assembler to check this, it was found that several pieces of assembly code were assuming this behaviour, and in one case getting it wrong. So this patch explicitly sign extends any immediate operands, which makes it obvious what is happening, and fixes the one case which got it wrong. Signed-off-by: Stuart Menefy <stuart.menefy@st.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-24 12:09:53 +04:00
mov #0xffffffe0, r1
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-17 02:20:36 +04:00
!
! r4..(r4+31)&~32 -------- not aligned [ Area 0 ]
! (r4+31)&~32..(r4+r5)&~32 -------- aligned [ Area 1 ]
! (r4+r5)&~32..r4+r5 -------- not aligned [ Area 2 ]
!
! Clear area 0
mov r4, r2
!
tst r1, r5 ! length < 32
bt .Larea2 ! skip to remainder
!
add #31, r2
and r1, r2
cmp/eq r4, r2
bt .Larea1
mov r2, r3
sub r4, r3
mov r3, r7
mov r4, r2
!
.L0: dt r3
0: mov.b r0, @r2
bf/s .L0
add #1, r2
!
sub r7, r5
mov r2, r4
.Larea1:
mov r4, r3
add r5, r3
and r1, r3
cmp/hi r2, r3
bf .Larea2
!
! Clear area 1
#if defined(CONFIG_CPU_SH4)
1: movca.l r0, @r2
#else
1: mov.l r0, @r2
#endif
add #4, r2
2: mov.l r0, @r2
add #4, r2
3: mov.l r0, @r2
add #4, r2
4: mov.l r0, @r2
add #4, r2
5: mov.l r0, @r2
add #4, r2
6: mov.l r0, @r2
add #4, r2
7: mov.l r0, @r2
add #4, r2
8: mov.l r0, @r2
add #4, r2
cmp/hi r2, r3
bt/s 1b
nop
!
! Clear area 2
.Larea2:
mov r4, r3
add r5, r3
cmp/hs r3, r2
bt/s .Ldone
sub r2, r3
.L2: dt r3
9: mov.b r0, @r2
bf/s .L2
add #1, r2
!
.Ldone: rts
mov #0, r0 ! return 0 as normal return
! return the number of bytes remained
.Lbad_clear_user:
mov r4, r0
add r5, r0
rts
sub r2, r0
.section __ex_table,"a"
.align 2
.long 0b, .Lbad_clear_user
.long 1b, .Lbad_clear_user
.long 2b, .Lbad_clear_user
.long 3b, .Lbad_clear_user
.long 4b, .Lbad_clear_user
.long 5b, .Lbad_clear_user
.long 6b, .Lbad_clear_user
.long 7b, .Lbad_clear_user
.long 8b, .Lbad_clear_user
.long 9b, .Lbad_clear_user
.previous
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