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linux/arch/arm/lib/io-writesw-armv3.S

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ArmAsm
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ARM: Bring back ARMv3 IO and user access code This partially reverts 357c9c1f07d4546bc3fbc0fd1044d96b114d14ed (ARM: Remove support for ARMv3 ARM610 and ARM710 CPUs). Although we only support StrongARM on the RiscPC, we need to keep the ARMv3 user access code for this platform because the bus does not understand half-word load/stores. Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-08-13 10:44:13 +00:00
/*
* linux/arch/arm/lib/io-writesw-armv3.S
*
* Copyright (C) 1995-2000 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
.Loutsw_bad_alignment:
adr r0, .Loutsw_bad_align_msg
mov r2, lr
b panic
.Loutsw_bad_align_msg:
.asciz "outsw: bad buffer alignment (0x%p, lr=0x%08lX)\n"
.align
.Loutsw_align: tst r1, #1
bne .Loutsw_bad_alignment
add r1, r1, #2
ldr r3, [r1, #-4]
mov r3, r3, lsr #16
orr r3, r3, r3, lsl #16
str r3, [r0]
subs r2, r2, #1
ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ ARMv6 and greater introduced a new instruction ("bx") which can be used to return from function calls. Recent CPUs perform better when the "bx lr" instruction is used rather than the "mov pc, lr" instruction, and this sequence is strongly recommended to be used by the ARM architecture manual (section A.4.1.1). We provide a new macro "ret" with all its variants for the condition code which will resolve to the appropriate instruction. Rather than doing this piecemeal, and miss some instances, change all the "mov pc" instances to use the new macro, with the exception of the "movs" instruction and the kprobes code. This allows us to detect the "mov pc, lr" case and fix it up - and also gives us the possibility of deploying this for other registers depending on the CPU selection. Reported-by: Will Deacon <will.deacon@arm.com> Tested-by: Stephen Warren <swarren@nvidia.com> # Tegra Jetson TK1 Tested-by: Robert Jarzmik <robert.jarzmik@free.fr> # mioa701_bootresume.S Tested-by: Andrew Lunn <andrew@lunn.ch> # Kirkwood Tested-by: Shawn Guo <shawn.guo@freescale.com> Tested-by: Tony Lindgren <tony@atomide.com> # OMAPs Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com> # Armada XP, 375, 385 Acked-by: Sekhar Nori <nsekhar@ti.com> # DaVinci Acked-by: Christoffer Dall <christoffer.dall@linaro.org> # kvm/hyp Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com> # PXA3xx Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> # Xen Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # ARMv7M Tested-by: Simon Horman <horms+renesas@verge.net.au> # Shmobile Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-06-30 15:29:12 +00:00
reteq lr
ARM: Bring back ARMv3 IO and user access code This partially reverts 357c9c1f07d4546bc3fbc0fd1044d96b114d14ed (ARM: Remove support for ARMv3 ARM610 and ARM710 CPUs). Although we only support StrongARM on the RiscPC, we need to keep the ARMv3 user access code for this platform because the bus does not understand half-word load/stores. Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-08-13 10:44:13 +00:00
ENTRY(__raw_writesw)
teq r2, #0 @ do we have to check for the zero len?
ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ ARMv6 and greater introduced a new instruction ("bx") which can be used to return from function calls. Recent CPUs perform better when the "bx lr" instruction is used rather than the "mov pc, lr" instruction, and this sequence is strongly recommended to be used by the ARM architecture manual (section A.4.1.1). We provide a new macro "ret" with all its variants for the condition code which will resolve to the appropriate instruction. Rather than doing this piecemeal, and miss some instances, change all the "mov pc" instances to use the new macro, with the exception of the "movs" instruction and the kprobes code. This allows us to detect the "mov pc, lr" case and fix it up - and also gives us the possibility of deploying this for other registers depending on the CPU selection. Reported-by: Will Deacon <will.deacon@arm.com> Tested-by: Stephen Warren <swarren@nvidia.com> # Tegra Jetson TK1 Tested-by: Robert Jarzmik <robert.jarzmik@free.fr> # mioa701_bootresume.S Tested-by: Andrew Lunn <andrew@lunn.ch> # Kirkwood Tested-by: Shawn Guo <shawn.guo@freescale.com> Tested-by: Tony Lindgren <tony@atomide.com> # OMAPs Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com> # Armada XP, 375, 385 Acked-by: Sekhar Nori <nsekhar@ti.com> # DaVinci Acked-by: Christoffer Dall <christoffer.dall@linaro.org> # kvm/hyp Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com> # PXA3xx Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> # Xen Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # ARMv7M Tested-by: Simon Horman <horms+renesas@verge.net.au> # Shmobile Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-06-30 15:29:12 +00:00
reteq lr
ARM: Bring back ARMv3 IO and user access code This partially reverts 357c9c1f07d4546bc3fbc0fd1044d96b114d14ed (ARM: Remove support for ARMv3 ARM610 and ARM710 CPUs). Although we only support StrongARM on the RiscPC, we need to keep the ARMv3 user access code for this platform because the bus does not understand half-word load/stores. Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-08-13 10:44:13 +00:00
tst r1, #3
bne .Loutsw_align
stmfd sp!, {r4, r5, r6, lr}
subs r2, r2, #8
bmi .Lno_outsw_8
.Loutsw_8_lp: ldmia r1!, {r3, r4, r5, r6}
mov ip, r3, lsl #16
orr ip, ip, ip, lsr #16
str ip, [r0]
mov ip, r3, lsr #16
orr ip, ip, ip, lsl #16
str ip, [r0]
mov ip, r4, lsl #16
orr ip, ip, ip, lsr #16
str ip, [r0]
mov ip, r4, lsr #16
orr ip, ip, ip, lsl #16
str ip, [r0]
mov ip, r5, lsl #16
orr ip, ip, ip, lsr #16
str ip, [r0]
mov ip, r5, lsr #16
orr ip, ip, ip, lsl #16
str ip, [r0]
mov ip, r6, lsl #16
orr ip, ip, ip, lsr #16
str ip, [r0]
mov ip, r6, lsr #16
orr ip, ip, ip, lsl #16
str ip, [r0]
subs r2, r2, #8
bpl .Loutsw_8_lp
tst r2, #7
ldmeqfd sp!, {r4, r5, r6, pc}
.Lno_outsw_8: tst r2, #4
beq .Lno_outsw_4
ldmia r1!, {r3, r4}
mov ip, r3, lsl #16
orr ip, ip, ip, lsr #16
str ip, [r0]
mov ip, r3, lsr #16
orr ip, ip, ip, lsl #16
str ip, [r0]
mov ip, r4, lsl #16
orr ip, ip, ip, lsr #16
str ip, [r0]
mov ip, r4, lsr #16
orr ip, ip, ip, lsl #16
str ip, [r0]
.Lno_outsw_4: tst r2, #2
beq .Lno_outsw_2
ldr r3, [r1], #4
mov ip, r3, lsl #16
orr ip, ip, ip, lsr #16
str ip, [r0]
mov ip, r3, lsr #16
orr ip, ip, ip, lsl #16
str ip, [r0]
.Lno_outsw_2: tst r2, #1
ldrne r3, [r1]
movne ip, r3, lsl #16
orrne ip, ip, ip, lsr #16
strne ip, [r0]
ldmfd sp!, {r4, r5, r6, pc}
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