From mboxrd@z Thu Jan 1 00:00:00 1970 From: robherring2@gmail.com (Rob Herring) Date: Wed, 14 Aug 2013 18:07:18 -0500 Subject: [PATCH v3] ARM: Add check for Cortex-A15 errata 798181 ECO Message-ID: <1376521638-24369-1-git-send-email-robherring2@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Rob Herring The work-around for A15 errata 798181 is not needed if appropriate ECO fixes have been applied to r3p2 and earlier core revisions. This can be checked by reading REVIDR register bits 4 and 9. If only bit 4 is set, then the IPI broadcast can be skipped. Signed-off-by: Rob Herring --- v3: - Rebase to v3.11-rc5 due to commit 1f49856 (ARM: 7789/1: Do not run dummy_flush_tlb_a15_erratum() on non-Cortex-A15) - Move the revision checking out of line and use function ptrs. I'm open to suggestions if there is a better place than setup.c for the init. arch/arm/include/asm/cputype.h | 1 + arch/arm/include/asm/tlbflush.h | 30 +++++++----------------------- arch/arm/kernel/setup.c | 38 ++++++++++++++++++++++++++++++++++++++ arch/arm/kernel/smp_tlb.c | 2 -- arch/arm/mm/context.c | 3 +-- 5 files changed, 47 insertions(+), 27 deletions(-) diff --git a/arch/arm/include/asm/cputype.h b/arch/arm/include/asm/cputype.h index 9672e97..acdde76 100644 --- a/arch/arm/include/asm/cputype.h +++ b/arch/arm/include/asm/cputype.h @@ -10,6 +10,7 @@ #define CPUID_TLBTYPE 3 #define CPUID_MPUIR 4 #define CPUID_MPIDR 5 +#define CPUID_REVIDR 6 #ifdef CONFIG_CPU_V7M #define CPUID_EXT_PFR0 0x40 diff --git a/arch/arm/include/asm/tlbflush.h b/arch/arm/include/asm/tlbflush.h index f467e9b..5c12ae8 100644 --- a/arch/arm/include/asm/tlbflush.h +++ b/arch/arm/include/asm/tlbflush.h @@ -443,34 +443,18 @@ static inline void local_flush_bp_all(void) isb(); } -#include #ifdef CONFIG_ARM_ERRATA_798181 -static inline int erratum_a15_798181(void) +extern bool (*erratum_a15_798181_handler)(void); +static inline bool erratum_a15_798181(void) { - unsigned int midr = read_cpuid_id(); - - /* Cortex-A15 r0p0..r3p2 affected */ - if ((midr & 0xff0ffff0) != 0x410fc0f0 || midr > 0x413fc0f2) - return 0; - return 1; -} - -static inline void dummy_flush_tlb_a15_erratum(void) -{ - /* - * Dummy TLBIMVAIS. Using the unmapped address 0 and ASID 0. - */ - asm("mcr p15, 0, %0, c8, c3, 1" : : "r" (0)); - dsb(); + if (unlikely(erratum_a15_798181_handler)) + return erratum_a15_798181_handler(); + return false; } #else -static inline int erratum_a15_798181(void) -{ - return 0; -} - -static inline void dummy_flush_tlb_a15_erratum(void) +static inline bool erratum_a15_798181(void) { + return false; } #endif diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index afc2489..052aa90 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -551,6 +551,42 @@ static void __init smp_build_mpidr_hash(void) } #endif +#ifdef CONFIG_ARM_ERRATA_798181 +bool (*erratum_a15_798181_handler)(void); + +static bool erratum_a15_798181_partial(void) +{ + asm("mcr p15, 0, %0, c8, c3, 1" : : "r" (0)); + dsb(); + return false; +} + +static bool erratum_a15_798181_broadcast(void) +{ + asm("mcr p15, 0, %0, c8, c3, 1" : : "r" (0)); + dsb(); + return true; +} + +static void erratum_a15_798181_init(void) +{ + unsigned int midr = read_cpuid_id(); + unsigned int revidr = read_cpuid(CPUID_REVIDR); + + /* Cortex-A15 r0p0..r3p2 w/o ECO fix affected */ + if ((midr & 0xff0ffff0) != 0x410fc0f0 || midr > 0x413fc0f2 || + (revidr & 0x210) == 0x210) { + return; + } + if (revidr & 0x10) + erratum_a15_798181_handler = erratum_a15_798181_partial; + else + erratum_a15_798181_handler = erratum_a15_798181_broadcast; +} +#else +static void erratum_a15_798181_init(void) {} +#endif + static void __init setup_processor(void) { struct proc_info_list *list; @@ -599,6 +635,8 @@ static void __init setup_processor(void) elf_hwcap &= ~(HWCAP_THUMB | HWCAP_IDIVT); #endif + erratum_a15_798181_init(); + feat_v6_fixup(); cacheid_init(); diff --git a/arch/arm/kernel/smp_tlb.c b/arch/arm/kernel/smp_tlb.c index c2edfff..94f917d 100644 --- a/arch/arm/kernel/smp_tlb.c +++ b/arch/arm/kernel/smp_tlb.c @@ -80,7 +80,6 @@ static void broadcast_tlb_a15_erratum(void) if (!erratum_a15_798181()) return; - dummy_flush_tlb_a15_erratum(); smp_call_function(ipi_flush_tlb_a15_erratum, NULL, 1); } @@ -92,7 +91,6 @@ static void broadcast_tlb_mm_a15_erratum(struct mm_struct *mm) if (!erratum_a15_798181()) return; - dummy_flush_tlb_a15_erratum(); this_cpu = get_cpu(); a15_erratum_get_cpumask(this_cpu, mm, &mask); smp_call_function_many(&mask, ipi_flush_tlb_a15_erratum, NULL, 1); diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c index 4a05444..28daa1c 100644 --- a/arch/arm/mm/context.c +++ b/arch/arm/mm/context.c @@ -245,8 +245,7 @@ void check_and_switch_context(struct mm_struct *mm, struct task_struct *tsk) if (cpumask_test_and_clear_cpu(cpu, &tlb_flush_pending)) { local_flush_bp_all(); local_flush_tlb_all(); - if (erratum_a15_798181()) - dummy_flush_tlb_a15_erratum(); + erratum_a15_798181(); } atomic64_set(&per_cpu(active_asids, cpu), asid); -- 1.8.1.2