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authorRussell King <rmk+kernel@arm.linux.org.uk>2014-06-30 17:29:12 +0200
committerRussell King <rmk+kernel@arm.linux.org.uk>2014-07-18 13:29:04 +0200
commit6ebbf2ce437b33022d30badd49dc94d33ecfa498 (patch)
treebc015e35b456a28bb0e501803a454dc0c0d3291a /arch/arm/mm/cache-v7.S
parentARM: make it easier to check the CPU part number correctly (diff)
downloadlinux-6ebbf2ce437b33022d30badd49dc94d33ecfa498.tar.xz
linux-6ebbf2ce437b33022d30badd49dc94d33ecfa498.zip
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>
Diffstat (limited to 'arch/arm/mm/cache-v7.S')
-rw-r--r--arch/arm/mm/cache-v7.S30
1 files changed, 15 insertions, 15 deletions
diff --git a/arch/arm/mm/cache-v7.S b/arch/arm/mm/cache-v7.S
index 615c99e38ba1..b966656d2c2d 100644
--- a/arch/arm/mm/cache-v7.S
+++ b/arch/arm/mm/cache-v7.S
@@ -61,7 +61,7 @@ ENTRY(v7_invalidate_l1)
bgt 1b
dsb st
isb
- mov pc, lr
+ ret lr
ENDPROC(v7_invalidate_l1)
/*
@@ -76,7 +76,7 @@ ENTRY(v7_flush_icache_all)
mov r0, #0
ALT_SMP(mcr p15, 0, r0, c7, c1, 0) @ invalidate I-cache inner shareable
ALT_UP(mcr p15, 0, r0, c7, c5, 0) @ I+BTB cache invalidate
- mov pc, lr
+ ret lr
ENDPROC(v7_flush_icache_all)
/*
@@ -94,7 +94,7 @@ ENTRY(v7_flush_dcache_louis)
ALT_UP(ands r3, r0, #(7 << 27)) @ extract LoUU from clidr
#ifdef CONFIG_ARM_ERRATA_643719
ALT_SMP(mrceq p15, 0, r2, c0, c0, 0) @ read main ID register
- ALT_UP(moveq pc, lr) @ LoUU is zero, so nothing to do
+ ALT_UP(reteq lr) @ LoUU is zero, so nothing to do
ldreq r1, =0x410fc090 @ ID of ARM Cortex A9 r0p?
biceq r2, r2, #0x0000000f @ clear minor revision number
teqeq r2, r1 @ test for errata affected core and if so...
@@ -102,7 +102,7 @@ ENTRY(v7_flush_dcache_louis)
#endif
ALT_SMP(mov r3, r3, lsr #20) @ r3 = LoUIS * 2
ALT_UP(mov r3, r3, lsr #26) @ r3 = LoUU * 2
- moveq pc, lr @ return if level == 0
+ reteq lr @ return if level == 0
mov r10, #0 @ r10 (starting level) = 0
b flush_levels @ start flushing cache levels
ENDPROC(v7_flush_dcache_louis)
@@ -168,7 +168,7 @@ finished:
mcr p15, 2, r10, c0, c0, 0 @ select current cache level in cssr
dsb st
isb
- mov pc, lr
+ ret lr
ENDPROC(v7_flush_dcache_all)
/*
@@ -191,7 +191,7 @@ ENTRY(v7_flush_kern_cache_all)
ALT_UP(mcr p15, 0, r0, c7, c5, 0) @ I+BTB cache invalidate
ARM( ldmfd sp!, {r4-r5, r7, r9-r11, lr} )
THUMB( ldmfd sp!, {r4-r7, r9-r11, lr} )
- mov pc, lr
+ ret lr
ENDPROC(v7_flush_kern_cache_all)
/*
@@ -209,7 +209,7 @@ ENTRY(v7_flush_kern_cache_louis)
ALT_UP(mcr p15, 0, r0, c7, c5, 0) @ I+BTB cache invalidate
ARM( ldmfd sp!, {r4-r5, r7, r9-r11, lr} )
THUMB( ldmfd sp!, {r4-r7, r9-r11, lr} )
- mov pc, lr
+ ret lr
ENDPROC(v7_flush_kern_cache_louis)
/*
@@ -235,7 +235,7 @@ ENTRY(v7_flush_user_cache_all)
* - we have a VIPT cache.
*/
ENTRY(v7_flush_user_cache_range)
- mov pc, lr
+ ret lr
ENDPROC(v7_flush_user_cache_all)
ENDPROC(v7_flush_user_cache_range)
@@ -296,7 +296,7 @@ ENTRY(v7_coherent_user_range)
ALT_UP(mcr p15, 0, r0, c7, c5, 6) @ invalidate BTB
dsb ishst
isb
- mov pc, lr
+ ret lr
/*
* Fault handling for the cache operation above. If the virtual address in r0
@@ -307,7 +307,7 @@ ENTRY(v7_coherent_user_range)
dsb
#endif
mov r0, #-EFAULT
- mov pc, lr
+ ret lr
UNWIND(.fnend )
ENDPROC(v7_coherent_kern_range)
ENDPROC(v7_coherent_user_range)
@@ -336,7 +336,7 @@ ENTRY(v7_flush_kern_dcache_area)
cmp r0, r1
blo 1b
dsb st
- mov pc, lr
+ ret lr
ENDPROC(v7_flush_kern_dcache_area)
/*
@@ -369,7 +369,7 @@ v7_dma_inv_range:
cmp r0, r1
blo 1b
dsb st
- mov pc, lr
+ ret lr
ENDPROC(v7_dma_inv_range)
/*
@@ -391,7 +391,7 @@ v7_dma_clean_range:
cmp r0, r1
blo 1b
dsb st
- mov pc, lr
+ ret lr
ENDPROC(v7_dma_clean_range)
/*
@@ -413,7 +413,7 @@ ENTRY(v7_dma_flush_range)
cmp r0, r1
blo 1b
dsb st
- mov pc, lr
+ ret lr
ENDPROC(v7_dma_flush_range)
/*
@@ -439,7 +439,7 @@ ENTRY(v7_dma_unmap_area)
add r1, r1, r0
teq r2, #DMA_TO_DEVICE
bne v7_dma_inv_range
- mov pc, lr
+ ret lr
ENDPROC(v7_dma_unmap_area)
__INITDATA