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authorRussell King <rmk+kernel@arm.linux.org.uk>2014-06-30 19:29:12 +0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2014-07-18 15:29:04 +0400
commit6ebbf2ce437b33022d30badd49dc94d33ecfa498 (patch)
treebc015e35b456a28bb0e501803a454dc0c0d3291a /arch/arm/mm/l2c-l2x0-resume.S
parentaf040ffc9ba1e079ee4c0748aff64fa3d4716fa5 (diff)
downloadlinux-6ebbf2ce437b33022d30badd49dc94d33ecfa498.tar.xz
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/l2c-l2x0-resume.S')
-rw-r--r--arch/arm/mm/l2c-l2x0-resume.S7
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/arm/mm/l2c-l2x0-resume.S b/arch/arm/mm/l2c-l2x0-resume.S
index 99b05f21a59a..fda415e4ca8f 100644
--- a/arch/arm/mm/l2c-l2x0-resume.S
+++ b/arch/arm/mm/l2c-l2x0-resume.S
@@ -6,6 +6,7 @@
* This code can only be used to if you are running in the secure world.
*/
#include <linux/linkage.h>
+#include <asm/assembler.h>
#include <asm/hardware/cache-l2x0.h>
.text
@@ -27,7 +28,7 @@ ENTRY(l2c310_early_resume)
@ Check that the address has been initialised
teq r1, #0
- moveq pc, lr
+ reteq lr
@ The prefetch and power control registers are revision dependent
@ and can be written whether or not the L2 cache is enabled
@@ -41,7 +42,7 @@ ENTRY(l2c310_early_resume)
@ Don't setup the L2 cache if it is already enabled
ldr r0, [r1, #L2X0_CTRL]
tst r0, #L2X0_CTRL_EN
- movne pc, lr
+ retne lr
str r3, [r1, #L310_TAG_LATENCY_CTRL]
str r4, [r1, #L310_DATA_LATENCY_CTRL]
@@ -51,7 +52,7 @@ ENTRY(l2c310_early_resume)
str r2, [r1, #L2X0_AUX_CTRL]
mov r9, #L2X0_CTRL_EN
str r9, [r1, #L2X0_CTRL]
- mov pc, lr
+ ret lr
ENDPROC(l2c310_early_resume)
.align