From: Will Deacon Date: Mon, 15 Jul 2013 13:26:19 +0000 (+0100) Subject: ARM: 7784/1: mm: ensure SMP alternates assemble to exactly 4 bytes with Thumb-2 X-Git-Tag: firefly_0821_release~176^2~5508^2~20 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=bf3f0f332f76a85ff3a0b393aaded5a8533769c0;p=firefly-linux-kernel-4.4.55.git ARM: 7784/1: mm: ensure SMP alternates assemble to exactly 4 bytes with Thumb-2 Commit ae8a8b9553bd ("ARM: 7691/1: mm: kill unused TLB_CAN_READ_FROM_L1_CACHE and use ALT_SMP instead") added early function returns for page table cache flushing operations on ARMv7 SMP CPUs. Unfortunately, when targetting Thumb-2, these `mov pc, lr' sequences assemble to 2 bytes which can lead to corruption of the instruction stream after code patching. This patch fixes the alternates to use wide (32-bit) instructions for Thumb-2, therefore ensuring that the patching code works correctly. Cc: Signed-off-by: Will Deacon Signed-off-by: Russell King --- diff --git a/arch/arm/mm/proc-v7-2level.S b/arch/arm/mm/proc-v7-2level.S index f64afb9f1bd5..bdd3be4be77a 100644 --- a/arch/arm/mm/proc-v7-2level.S +++ b/arch/arm/mm/proc-v7-2level.S @@ -110,7 +110,7 @@ ENTRY(cpu_v7_set_pte_ext) ARM( str r3, [r0, #2048]! ) THUMB( add r0, r0, #2048 ) THUMB( str r3, [r0] ) - ALT_SMP(mov pc,lr) + ALT_SMP(W(nop)) ALT_UP (mcr p15, 0, r0, c7, c10, 1) @ flush_pte #endif mov pc, lr diff --git a/arch/arm/mm/proc-v7-3level.S b/arch/arm/mm/proc-v7-3level.S index c36ac69488c8..01a719e18bb0 100644 --- a/arch/arm/mm/proc-v7-3level.S +++ b/arch/arm/mm/proc-v7-3level.S @@ -81,7 +81,7 @@ ENTRY(cpu_v7_set_pte_ext) tst r3, #1 << (55 - 32) @ L_PTE_DIRTY orreq r2, #L_PTE_RDONLY 1: strd r2, r3, [r0] - ALT_SMP(mov pc, lr) + ALT_SMP(W(nop)) ALT_UP (mcr p15, 0, r0, c7, c10, 1) @ flush_pte #endif mov pc, lr diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index 5c6d5a3050ea..73398bcf9bd8 100644 --- a/arch/arm/mm/proc-v7.S +++ b/arch/arm/mm/proc-v7.S @@ -75,13 +75,14 @@ ENTRY(cpu_v7_do_idle) ENDPROC(cpu_v7_do_idle) ENTRY(cpu_v7_dcache_clean_area) - ALT_SMP(mov pc, lr) @ MP extensions imply L1 PTW - ALT_UP(W(nop)) - dcache_line_size r2, r3 -1: mcr p15, 0, r0, c7, c10, 1 @ clean D entry + ALT_SMP(W(nop)) @ MP extensions imply L1 PTW + ALT_UP_B(1f) + mov pc, lr +1: dcache_line_size r2, r3 +2: mcr p15, 0, r0, c7, c10, 1 @ clean D entry add r0, r0, r2 subs r1, r1, r2 - bhi 1b + bhi 2b dsb mov pc, lr ENDPROC(cpu_v7_dcache_clean_area)