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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/tlb-fa.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/tlb-fa.S')
-rw-r--r--arch/arm/mm/tlb-fa.S7
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/arm/mm/tlb-fa.S b/arch/arm/mm/tlb-fa.S
index d3ddcf9a76ca..d2d9ecbe0aac 100644
--- a/arch/arm/mm/tlb-fa.S
+++ b/arch/arm/mm/tlb-fa.S
@@ -18,6 +18,7 @@
*/
#include <linux/linkage.h>
#include <linux/init.h>
+#include <asm/assembler.h>
#include <asm/asm-offsets.h>
#include <asm/tlbflush.h>
#include "proc-macros.S"
@@ -37,7 +38,7 @@ ENTRY(fa_flush_user_tlb_range)
vma_vm_mm ip, r2
act_mm r3 @ get current->active_mm
eors r3, ip, r3 @ == mm ?
- movne pc, lr @ no, we dont do anything
+ retne lr @ no, we dont do anything
mov r3, #0
mcr p15, 0, r3, c7, c10, 4 @ drain WB
bic r0, r0, #0x0ff
@@ -47,7 +48,7 @@ ENTRY(fa_flush_user_tlb_range)
cmp r0, r1
blo 1b
mcr p15, 0, r3, c7, c10, 4 @ data write barrier
- mov pc, lr
+ ret lr
ENTRY(fa_flush_kern_tlb_range)
@@ -61,7 +62,7 @@ ENTRY(fa_flush_kern_tlb_range)
blo 1b
mcr p15, 0, r3, c7, c10, 4 @ data write barrier
mcr p15, 0, r3, c7, c5, 4 @ prefetch flush (isb)
- mov pc, lr
+ ret lr
__INITDATA