From mboxrd@z Thu Jan 1 00:00:00 1970 From: suzuki.poulose@arm.com (Suzuki K Poulose) Date: Mon, 25 Jan 2016 18:07:04 +0000 Subject: [PATCH v4 6/7] arm64: Add helper for extracting ASIDBits In-Reply-To: <1453745225-27736-1-git-send-email-suzuki.poulose@arm.com> References: <1453745225-27736-1-git-send-email-suzuki.poulose@arm.com> Message-ID: <1453745225-27736-7-git-send-email-suzuki.poulose@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Suzuki K. Poulose Add a helper to extract ASIDBits on the current cpu Cc: Will Deacon Cc: Mark Rutland Cc: Catalin Marinas Signed-off-by: Suzuki K. Poulose --- arch/arm64/mm/context.c | 36 +++++++++++++++++++++++------------- 1 file changed, 23 insertions(+), 13 deletions(-) diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c index e87f53f..643bf4b 100644 --- a/arch/arm64/mm/context.c +++ b/arch/arm64/mm/context.c @@ -40,6 +40,28 @@ static cpumask_t tlb_flush_pending; #define ASID_FIRST_VERSION (1UL << asid_bits) #define NUM_USER_ASIDS ASID_FIRST_VERSION +/* Get the ASIDBits supported by the current CPU */ +static u32 get_cpu_asid_bits(void) +{ + u32 asid; + int fld = cpuid_feature_extract_field(read_cpuid(ID_AA64MMFR0_EL1), + ID_AA64MMFR0_ASID_SHIFT); + + switch (fld) { + default: + pr_warn("CPU%d: Unknown ASID size (%d); assuming 8-bit\n", + smp_processor_id(), fld); + /* Fallthrough */ + case 0: + asid = 8; + break; + case 2: + asid = 16; + } + + return asid; +} + static void flush_context(unsigned int cpu) { int i; @@ -187,19 +209,7 @@ switch_mm_fastpath: static int asids_init(void) { - int fld = cpuid_feature_extract_field(read_cpuid(ID_AA64MMFR0_EL1), 4); - - switch (fld) { - default: - pr_warn("Unknown ASID size (%d); assuming 8-bit\n", fld); - /* Fallthrough */ - case 0: - asid_bits = 8; - break; - case 2: - asid_bits = 16; - } - + asid_bits = get_cpu_asid_bits(); /* If we end up with more CPUs than ASIDs, expect things to crash */ WARN_ON(NUM_USER_ASIDS < num_possible_cpus()); atomic64_set(&asid_generation, ASID_FIRST_VERSION); -- 1.7.9.5