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From: Zhenyu Ye <yezhenyu2@huawei.com>
To: <will@kernel.org>, <mark.rutland@arm.com>,
	<catalin.marinas@arm.com>, <aneesh.kumar@linux.ibm.com>,
	<akpm@linux-foundation.org>, <npiggin@gmail.com>,
	<peterz@infradead.org>, <arnd@arndb.de>, <rostedt@goodmis.org>,
	<maz@kernel.org>, <suzuki.poulose@arm.com>, <tglx@linutronix.de>,
	<yuzhao@google.com>, <Dave.Martin@arm.com>,
	<steven.price@arm.com>, <broonie@kernel.org>,
	<guohanjun@huawei.com>
Cc: <yezhenyu2@huawei.com>, <linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, <linux-arch@vger.kernel.org>,
	<linux-mm@kvack.org>, <arm@kernel.org>, <xiexiangyou@huawei.com>,
	<prime.zeng@hisilicon.com>, <zhangshaokun@hisilicon.com>
Subject: [RFC PATCH v4 1/6] arm64: Detect the ARMv8.4 TTL feature
Date: Tue, 24 Mar 2020 21:45:29 +0800	[thread overview]
Message-ID: <20200324134534.1570-2-yezhenyu2@huawei.com> (raw)
In-Reply-To: <20200324134534.1570-1-yezhenyu2@huawei.com>

From: Marc Zyngier <maz@kernel.org>

In order to reduce the cost of TLB invalidation, the ARMv8.4 TTL
feature allows TLBs to be issued with a level allowing for quicker
invalidation.

Let's detect the feature for now. Further patches will implement
its actual usage.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Zhenyu Ye <yezhenyu2@huawei.com>
---
 arch/arm64/include/asm/cpucaps.h |  3 ++-
 arch/arm64/include/asm/sysreg.h  |  1 +
 arch/arm64/kernel/cpufeature.c   | 11 +++++++++++
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index 865e0253fc1e..8b3b4dd612b3 100644
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -58,7 +58,8 @@
 #define ARM64_WORKAROUND_SPECULATIVE_AT_NVHE	48
 #define ARM64_HAS_E0PD				49
 #define ARM64_HAS_RNG				50
+#define ARM64_HAS_ARMv8_4_TTL			51
 
-#define ARM64_NCAPS				51
+#define ARM64_NCAPS				52
 
 #endif /* __ASM_CPUCAPS_H */
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index b91570ff9db1..a28b76f32ba7 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -685,6 +685,7 @@
 
 /* id_aa64mmfr2 */
 #define ID_AA64MMFR2_E0PD_SHIFT		60
+#define ID_AA64MMFR2_TTL_SHIFT		48
 #define ID_AA64MMFR2_FWB_SHIFT		40
 #define ID_AA64MMFR2_AT_SHIFT		32
 #define ID_AA64MMFR2_LVA_SHIFT		16
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 0b6715625cf6..cbe46ad2900a 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -241,6 +241,7 @@ static const struct arm64_ftr_bits ftr_id_aa64mmfr1[] = {
 
 static const struct arm64_ftr_bits ftr_id_aa64mmfr2[] = {
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_E0PD_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_TTL_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_FWB_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_AT_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_LVA_SHIFT, 4, 0),
@@ -1523,6 +1524,16 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 		.matches = has_cpuid_feature,
 		.cpu_enable = cpu_has_fwb,
 	},
+	{
+		.desc = "ARMv8.4 Translation Table Level",
+		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
+		.capability = ARM64_HAS_ARMv8_4_TTL,
+		.sys_reg = SYS_ID_AA64MMFR2_EL1,
+		.sign = FTR_UNSIGNED,
+		.field_pos = ID_AA64MMFR2_TTL_SHIFT,
+		.min_field_value = 1,
+		.matches = has_cpuid_feature,
+	},
 #ifdef CONFIG_ARM64_HW_AFDBM
 	{
 		/*
-- 
2.19.1




  reply	other threads:[~2020-03-24 13:46 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-24 13:45 [RFC PATCH v4 0/6] arm64: tlb: add support for TTL feature Zhenyu Ye
2020-03-24 13:45 ` Zhenyu Ye [this message]
2020-03-24 13:45 ` [RFC PATCH v4 2/6] arm64: Add level-hinted TLB invalidation helper Zhenyu Ye
2020-03-24 13:45 ` [RFC PATCH v4 3/6] arm64: Add level-hinted TLB invalidation helper to tlbi_user Zhenyu Ye
2020-03-24 14:19   ` Marc Zyngier
2020-03-25  2:47     ` Zhenyu Ye
2020-03-24 13:45 ` [RFC PATCH v4 4/6] mm: Add page table level flags to vm_flags Zhenyu Ye
2020-03-24 18:44   ` Steven Rostedt
2020-03-25  2:10     ` yezhenyu (A)
2020-03-24 13:45 ` [RFC PATCH v4 5/6] arm64: tlb: Use translation level hint in vm_flags Zhenyu Ye
2020-03-24 14:45   ` Marc Zyngier
2020-03-25  8:00     ` Zhenyu Ye
2020-03-25 14:13       ` Marc Zyngier
2020-03-26  7:11         ` Zhenyu Ye
2020-03-24 13:45 ` [RFC PATCH v4 6/6] mm: Set VM_LEVEL flags in some tlb_flush functions Zhenyu Ye
2020-03-24 15:01 ` [RFC PATCH v4 0/6] arm64: tlb: add support for TTL feature Peter Zijlstra
2020-03-25  4:49   ` Zhenyu Ye
2020-03-25 13:32     ` Peter Zijlstra
2020-03-26  7:15       ` Zhenyu Ye
2020-03-25 16:15 ` James Morse
2020-03-25 16:41   ` Peter Zijlstra
2020-03-26  6:45   ` Zhenyu Ye

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