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/mm/proc-arm920.S | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-) (limited to 'arch/arm/mm/proc-arm920.S') diff --git a/arch/arm/mm/proc-arm920.S b/arch/arm/mm/proc-arm920.S index 549557df6d57..22bf8dde4f84 100644 --- a/arch/arm/mm/proc-arm920.S +++ b/arch/arm/mm/proc-arm920.S @@ -63,7 +63,7 @@ * cpu_arm920_proc_init() */ ENTRY(cpu_arm920_proc_init) - mov pc, lr + ret lr /* * cpu_arm920_proc_fin() @@ -73,7 +73,7 @@ ENTRY(cpu_arm920_proc_fin) bic r0, r0, #0x1000 @ ...i............ bic r0, r0, #0x000e @ ............wca. mcr p15, 0, r0, c1, c0, 0 @ disable caches - mov pc, lr + ret lr /* * cpu_arm920_reset(loc) @@ -97,7 +97,7 @@ ENTRY(cpu_arm920_reset) bic ip, ip, #0x000f @ ............wcam bic ip, ip, #0x1100 @ ...i...s........ mcr p15, 0, ip, c1, c0, 0 @ ctrl register - mov pc, r0 + ret r0 ENDPROC(cpu_arm920_reset) .popsection @@ -107,7 +107,7 @@ ENDPROC(cpu_arm920_reset) .align 5 ENTRY(cpu_arm920_do_idle) mcr p15, 0, r0, c7, c0, 4 @ Wait for interrupt - mov pc, lr + ret lr #ifndef CONFIG_CPU_DCACHE_WRITETHROUGH @@ -120,7 +120,7 @@ ENTRY(cpu_arm920_do_idle) ENTRY(arm920_flush_icache_all) mov r0, #0 mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache - mov pc, lr + ret lr ENDPROC(arm920_flush_icache_all) /* @@ -151,7 +151,7 @@ __flush_whole_cache: tst r2, #VM_EXEC mcrne p15, 0, ip, c7, c5, 0 @ invalidate I cache mcrne p15, 0, ip, c7, c10, 4 @ drain WB - mov pc, lr + ret lr /* * flush_user_cache_range(start, end, flags) @@ -177,7 +177,7 @@ ENTRY(arm920_flush_user_cache_range) blo 1b tst r2, #VM_EXEC mcrne p15, 0, ip, c7, c10, 4 @ drain WB - mov pc, lr + ret lr /* * coherent_kern_range(start, end) @@ -211,7 +211,7 @@ ENTRY(arm920_coherent_user_range) blo 1b mcr p15, 0, r0, c7, c10, 4 @ drain WB mov r0, #0 - mov pc, lr + ret lr /* * flush_kern_dcache_area(void *addr, size_t size) @@ -231,7 +231,7 @@ ENTRY(arm920_flush_kern_dcache_area) mov r0, #0 mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache mcr p15, 0, r0, c7, c10, 4 @ drain WB - mov pc, lr + ret lr /* * dma_inv_range(start, end) @@ -257,7 +257,7 @@ arm920_dma_inv_range: cmp r0, r1 blo 1b mcr p15, 0, r0, c7, c10, 4 @ drain WB - mov pc, lr + ret lr /* * dma_clean_range(start, end) @@ -276,7 +276,7 @@ arm920_dma_clean_range: cmp r0, r1 blo 1b mcr p15, 0, r0, c7, c10, 4 @ drain WB - mov pc, lr + ret lr /* * dma_flush_range(start, end) @@ -293,7 +293,7 @@ ENTRY(arm920_dma_flush_range) cmp r0, r1 blo 1b mcr p15, 0, r0, c7, c10, 4 @ drain WB - mov pc, lr + ret lr /* * dma_map_area(start, size, dir) @@ -316,7 +316,7 @@ ENDPROC(arm920_dma_map_area) * - dir - DMA direction */ ENTRY(arm920_dma_unmap_area) - mov pc, lr + ret lr ENDPROC(arm920_dma_unmap_area) .globl arm920_flush_kern_cache_louis @@ -332,7 +332,7 @@ ENTRY(cpu_arm920_dcache_clean_area) add r0, r0, #CACHE_DLINESIZE subs r1, r1, #CACHE_DLINESIZE bhi 1b - mov pc, lr + ret lr /* =============================== PageTable ============================== */ @@ -367,7 +367,7 @@ ENTRY(cpu_arm920_switch_mm) mcr p15, 0, r0, c2, c0, 0 @ load page table pointer mcr p15, 0, ip, c8, c7, 0 @ invalidate I & D TLBs #endif - mov pc, lr + ret lr /* * cpu_arm920_set_pte(ptep, pte, ext) @@ -382,7 +382,7 @@ ENTRY(cpu_arm920_set_pte_ext) mcr p15, 0, r0, c7, c10, 1 @ clean D entry mcr p15, 0, r0, c7, c10, 4 @ drain WB #endif - mov pc, lr + ret lr /* Suspend/resume support: taken from arch/arm/plat-s3c24xx/sleep.S */ .globl cpu_arm920_suspend_size @@ -423,7 +423,7 @@ __arm920_setup: mrc p15, 0, r0, c1, c0 @ get control register v4 bic r0, r0, r5 orr r0, r0, r6 - mov pc, lr + ret lr .size __arm920_setup, . - __arm920_setup /* -- cgit v1.2.3