From a6d746789825e4d7229523eebee233b03ad48c54 Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 7 Apr 2015 15:35:24 +0100 Subject: ARM: proc-v7: avoid errata 430973 workaround for non-Cortex A8 CPUs Avoid the errata 430973 workaround for non-Cortex A8 CPUs. Having this workaround enabled introduces an additional branch target buffer flush into the context switching path, something we wish to avoid. To allow this errata to be enabled in multiplatform kernels while reducing its impact, rearrange the Cortex-A8 CPU support to avoid impacting on other Version 7 CPUs. Tested-by: Tony Lindgren Signed-off-by: Russell King --- arch/arm/mm/proc-v7-2level.S | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'arch/arm/mm/proc-v7-2level.S') diff --git a/arch/arm/mm/proc-v7-2level.S b/arch/arm/mm/proc-v7-2level.S index ed448d8a596b..10405b8d31af 100644 --- a/arch/arm/mm/proc-v7-2level.S +++ b/arch/arm/mm/proc-v7-2level.S @@ -37,15 +37,18 @@ * It is assumed that: * - we are not using split page tables */ -ENTRY(cpu_v7_switch_mm) +ENTRY(cpu_ca8_switch_mm) #ifdef CONFIG_MMU mov r2, #0 - mmid r1, r1 @ get mm->context.id - ALT_SMP(orr r0, r0, #TTB_FLAGS_SMP) - ALT_UP(orr r0, r0, #TTB_FLAGS_UP) #ifdef CONFIG_ARM_ERRATA_430973 mcr p15, 0, r2, c7, c5, 6 @ flush BTAC/BTB #endif +#endif +ENTRY(cpu_v7_switch_mm) +#ifdef CONFIG_MMU + mmid r1, r1 @ get mm->context.id + ALT_SMP(orr r0, r0, #TTB_FLAGS_SMP) + ALT_UP(orr r0, r0, #TTB_FLAGS_UP) #ifdef CONFIG_PID_IN_CONTEXTIDR mrc p15, 0, r2, c13, c0, 1 @ read current context ID lsr r2, r2, #8 @ extract the PID @@ -61,6 +64,7 @@ ENTRY(cpu_v7_switch_mm) #endif bx lr ENDPROC(cpu_v7_switch_mm) +ENDPROC(cpu_ca8_switch_mm) /* * cpu_v7_set_pte_ext(ptep, pte) -- cgit