From 6ebbf2ce437b33022d30badd49dc94d33ecfa498 Mon Sep 17 00:00:00 2001 From: Russell King Date: Mon, 30 Jun 2014 16:29:12 +0100 Subject: ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Tested-by: Stephen Warren # Tegra Jetson TK1 Tested-by: Robert Jarzmik # mioa701_bootresume.S Tested-by: Andrew Lunn # Kirkwood Tested-by: Shawn Guo Tested-by: Tony Lindgren # OMAPs Tested-by: Gregory CLEMENT # Armada XP, 375, 385 Acked-by: Sekhar Nori # DaVinci Acked-by: Christoffer Dall # kvm/hyp Acked-by: Haojian Zhuang # PXA3xx Acked-by: Stefano Stabellini # Xen Tested-by: Uwe Kleine-König # ARMv7M Tested-by: Simon Horman # Shmobile Signed-off-by: Russell King --- arch/arm/mach-tegra/sleep-tegra30.S | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'arch/arm/mach-tegra/sleep-tegra30.S') diff --git a/arch/arm/mach-tegra/sleep-tegra30.S b/arch/arm/mach-tegra/sleep-tegra30.S index b16d4a57fa59..09cad9b071de 100644 --- a/arch/arm/mach-tegra/sleep-tegra30.S +++ b/arch/arm/mach-tegra/sleep-tegra30.S @@ -142,7 +142,7 @@ ENTRY(tegra30_hotplug_shutdown) /* Powergate this CPU */ mov r0, #TEGRA30_POWER_HOTPLUG_SHUTDOWN bl tegra30_cpu_shutdown - mov pc, lr @ should never get here + ret lr @ should never get here ENDPROC(tegra30_hotplug_shutdown) /* @@ -161,7 +161,7 @@ ENTRY(tegra30_cpu_shutdown) bne _no_cpu0_chk @ It's not Tegra30 cmp r3, #0 - moveq pc, lr @ Must never be called for CPU 0 + reteq lr @ Must never be called for CPU 0 _no_cpu0_chk: ldr r12, =TEGRA_FLOW_CTRL_VIRT @@ -266,7 +266,7 @@ ENTRY(tegra30_sleep_core_finish) mov32 r1, TEGRA_IRAM_LPx_RESUME_AREA add r0, r0, r1 - mov pc, r3 + ret r3 ENDPROC(tegra30_sleep_core_finish) /* @@ -285,7 +285,7 @@ ENTRY(tegra30_sleep_cpu_secondary_finish) mov r0, #0 @ power mode flags (!hotplug) bl tegra30_cpu_shutdown mov r0, #1 @ never return here - mov pc, r7 + ret r7 ENDPROC(tegra30_sleep_cpu_secondary_finish) /* @@ -529,7 +529,7 @@ __no_dual_emc_chanl: mov32 r0, TEGRA_PMC_BASE ldr r0, [r0, #PMC_SCRATCH41] - mov pc, r0 @ jump to tegra_resume + ret r0 @ jump to tegra_resume ENDPROC(tegra30_lp1_reset) .align L1_CACHE_SHIFT @@ -659,7 +659,7 @@ _no_pll_in_iddq: mov r0, #0 /* brust policy = 32KHz */ str r0, [r5, #CLK_RESET_SCLK_BURST] - mov pc, lr + ret lr /* * tegra30_enter_sleep @@ -819,7 +819,7 @@ pmc_io_dpd_skip: dsb - mov pc, lr + ret lr .ltorg /* dummy symbol for end of IRAM */ -- cgit