diff options
| author |   Russell King <rmk+kernel@arm.linux.org.uk> | 2014-06-30 16:29:12 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2014-07-18 12:29:04 +0100 |
| commit | 6ebbf2ce437b33022d30badd49dc94d33ecfa498 (patch) | |
| tree | bc015e35b456a28bb0e501803a454dc0c0d3291a /arch/arm/mach-omap2 | |
| parent | ARM: make it easier to check the CPU part number correctly (diff) | |
| download | linux-dev-6ebbf2ce437b33022d30badd49dc94d33ecfa498.tar.xz linux-dev-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/mach-omap2')
| -rw-r--r-- | arch/arm/mach-omap2/sleep44xx.S | 3 | ||||
| -rw-r--r-- | arch/arm/mach-omap2/sram242x.S | 6 | ||||
| -rw-r--r-- | arch/arm/mach-omap2/sram243x.S | 6 |
3 files changed, 8 insertions, 7 deletions
diff --git a/arch/arm/mach-omap2/sleep44xx.S b/arch/arm/mach-omap2/sleep44xx.S index 9086ce03ae12..b84a0122d823 100644 --- a/arch/arm/mach-omap2/sleep44xx.S +++ b/arch/arm/mach-omap2/sleep44xx.S @@ -10,6 +10,7 @@ */ #include <linux/linkage.h> +#include <asm/assembler.h> #include <asm/smp_scu.h> #include <asm/memory.h> #include <asm/hardware/cache-l2x0.h> @@ -334,7 +335,7 @@ ENDPROC(omap4_cpu_resume) #ifndef CONFIG_OMAP4_ERRATA_I688 ENTRY(omap_bus_sync) - mov pc, lr + ret lr ENDPROC(omap_bus_sync) #endif diff --git a/arch/arm/mach-omap2/sram242x.S b/arch/arm/mach-omap2/sram242x.S index 680a7c56cc3e..2c88ff2d0236 100644 --- a/arch/arm/mach-omap2/sram242x.S +++ b/arch/arm/mach-omap2/sram242x.S @@ -101,7 +101,7 @@ i_dll_wait: i_dll_delay: subs r4, r4, #0x1 bne i_dll_delay - mov pc, lr + ret lr /* * shift up or down voltage, use R9 as input to tell level. @@ -125,7 +125,7 @@ volt_delay: ldr r7, [r3] @ get timer value cmp r5, r7 @ time up? bhi volt_delay @ not yet->branch - mov pc, lr @ back to caller. + ret lr @ back to caller. omap242x_sdi_cm_clksel2_pll: .word OMAP2420_CM_REGADDR(PLL_MOD, CM_CLKSEL2) @@ -220,7 +220,7 @@ volt_delay_c: ldr r7, [r10] @ get timer value cmp r8, r7 @ time up? bhi volt_delay_c @ not yet->branch - mov pc, lr @ back to caller + ret lr @ back to caller omap242x_srs_cm_clksel2_pll: .word OMAP2420_CM_REGADDR(PLL_MOD, CM_CLKSEL2) diff --git a/arch/arm/mach-omap2/sram243x.S b/arch/arm/mach-omap2/sram243x.S index a1e9edd673f4..d5deb9761fc7 100644 --- a/arch/arm/mach-omap2/sram243x.S +++ b/arch/arm/mach-omap2/sram243x.S @@ -101,7 +101,7 @@ i_dll_wait: i_dll_delay: subs r4, r4, #0x1 bne i_dll_delay - mov pc, lr + ret lr /* * shift up or down voltage, use R9 as input to tell level. @@ -125,7 +125,7 @@ volt_delay: ldr r7, [r3] @ get timer value cmp r5, r7 @ time up? bhi volt_delay @ not yet->branch - mov pc, lr @ back to caller. + ret lr @ back to caller. omap243x_sdi_cm_clksel2_pll: .word OMAP2430_CM_REGADDR(PLL_MOD, CM_CLKSEL2) @@ -220,7 +220,7 @@ volt_delay_c: ldr r7, [r10] @ get timer value cmp r8, r7 @ time up? bhi volt_delay_c @ not yet->branch - mov pc, lr @ back to caller + ret lr @ back to caller omap243x_srs_cm_clksel2_pll: .word OMAP2430_CM_REGADDR(PLL_MOD, CM_CLKSEL2) |