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From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu
Cc: kernel-team@android.com,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>
Subject: [PATCH 09/17] arm64: cpufeature: Add global feature override facility
Date: Mon, 28 Dec 2020 10:49:50 +0000	[thread overview]
Message-ID: <20201228104958.1848833-10-maz@kernel.org> (raw)
In-Reply-To: <20201228104958.1848833-1-maz@kernel.org>

Add a facility to globally override a feature, no matter what
the HW says. Yes, this is dangerous.

Nothing uses this yet, so we are pretty safe. For now.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/cpufeature.h |  2 ++
 arch/arm64/kernel/cpufeature.c      | 26 +++++++++++++++++++++-----
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 9a555809b89c..465d2cb63bfc 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -75,6 +75,8 @@ struct arm64_ftr_reg {
 	u64				sys_val;
 	u64				user_val;
 	const struct arm64_ftr_bits	*ftr_bits;
+	u64				*override_val;
+	u64				*override_mask;
 };
 
 extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0;
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 7ffb5f1d8b68..2dbfc0096b0d 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -544,13 +544,17 @@ static const struct arm64_ftr_bits ftr_raz[] = {
 	ARM64_FTR_END,
 };
 
-#define ARM64_FTR_REG(id, table) {		\
-	.sys_id = id,				\
-	.reg = 	&(struct arm64_ftr_reg){	\
-		.name = #id,			\
-		.ftr_bits = &((table)[0]),	\
+#define ARM64_FTR_REG_OVERRIDE(id, table, v, m) {		\
+		.sys_id = id,					\
+		.reg = 	&(struct arm64_ftr_reg){		\
+			.name = #id,				\
+			.ftr_bits = &((table)[0]),		\
+			.override_val = v,			\
+			.override_mask = m,			\
 	}}
 
+#define ARM64_FTR_REG(id, table) ARM64_FTR_REG_OVERRIDE(id, table, NULL, NULL)
+
 static const struct __ftr_reg_entry {
 	u32			sys_id;
 	struct arm64_ftr_reg 	*reg;
@@ -786,6 +790,18 @@ static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new)
 
 	val &= valid_mask;
 
+	if (reg->override_mask && reg->override_val) {
+		u64 override = val;
+		override &= ~*reg->override_mask;
+		override |= (*reg->override_val & *reg->override_mask);
+
+		if (val != override)
+			pr_warn("%s: forced from %016llx to %016llx\n",
+				reg->name, val, override);
+
+		val = override;
+	}
+
 	reg->sys_val = val;
 	reg->strict_mask = strict_mask;
 	reg->user_mask = user_mask;
-- 
2.29.2

_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu
Cc: Mark Rutland <mark.rutland@arm.com>,
	kernel-team@android.com,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	James Morse <james.morse@arm.com>,
	David Brazdil <dbrazdil@google.com>,
	Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>,
	Julien Thierry <julien.thierry.kdev@gmail.com>
Subject: [PATCH 09/17] arm64: cpufeature: Add global feature override facility
Date: Mon, 28 Dec 2020 10:49:50 +0000	[thread overview]
Message-ID: <20201228104958.1848833-10-maz@kernel.org> (raw)
In-Reply-To: <20201228104958.1848833-1-maz@kernel.org>

Add a facility to globally override a feature, no matter what
the HW says. Yes, this is dangerous.

Nothing uses this yet, so we are pretty safe. For now.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/cpufeature.h |  2 ++
 arch/arm64/kernel/cpufeature.c      | 26 +++++++++++++++++++++-----
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 9a555809b89c..465d2cb63bfc 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -75,6 +75,8 @@ struct arm64_ftr_reg {
 	u64				sys_val;
 	u64				user_val;
 	const struct arm64_ftr_bits	*ftr_bits;
+	u64				*override_val;
+	u64				*override_mask;
 };
 
 extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0;
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 7ffb5f1d8b68..2dbfc0096b0d 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -544,13 +544,17 @@ static const struct arm64_ftr_bits ftr_raz[] = {
 	ARM64_FTR_END,
 };
 
-#define ARM64_FTR_REG(id, table) {		\
-	.sys_id = id,				\
-	.reg = 	&(struct arm64_ftr_reg){	\
-		.name = #id,			\
-		.ftr_bits = &((table)[0]),	\
+#define ARM64_FTR_REG_OVERRIDE(id, table, v, m) {		\
+		.sys_id = id,					\
+		.reg = 	&(struct arm64_ftr_reg){		\
+			.name = #id,				\
+			.ftr_bits = &((table)[0]),		\
+			.override_val = v,			\
+			.override_mask = m,			\
 	}}
 
+#define ARM64_FTR_REG(id, table) ARM64_FTR_REG_OVERRIDE(id, table, NULL, NULL)
+
 static const struct __ftr_reg_entry {
 	u32			sys_id;
 	struct arm64_ftr_reg 	*reg;
@@ -786,6 +790,18 @@ static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new)
 
 	val &= valid_mask;
 
+	if (reg->override_mask && reg->override_val) {
+		u64 override = val;
+		override &= ~*reg->override_mask;
+		override |= (*reg->override_val & *reg->override_mask);
+
+		if (val != override)
+			pr_warn("%s: forced from %016llx to %016llx\n",
+				reg->name, val, override);
+
+		val = override;
+	}
+
 	reg->sys_val = val;
 	reg->strict_mask = strict_mask;
 	reg->user_mask = user_mask;
-- 
2.29.2


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2020-12-28 10:50 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-28 10:49 [PATCH 00/17] arm64: Early CPU feature override, and an application to VHE Marc Zyngier
2020-12-28 10:49 ` Marc Zyngier
2020-12-28 10:49 ` [PATCH 01/17] arm64: Fix labels in el2_setup macros Marc Zyngier
2020-12-28 10:49   ` Marc Zyngier
2020-12-28 10:49 ` [PATCH 02/17] arm64: Fix outdated TCR setup comment Marc Zyngier
2020-12-28 10:49   ` Marc Zyngier
2020-12-28 10:49 ` [PATCH 03/17] arm64: Turn the MMU-on sequence into a macro Marc Zyngier
2020-12-28 10:49   ` Marc Zyngier
2020-12-28 10:49 ` [PATCH 04/17] arm64: Provide an 'upgrade to VHE' stub hypercall Marc Zyngier
2020-12-28 10:49   ` Marc Zyngier
2021-01-04 23:39   ` Jing Zhang
2021-01-04 23:39     ` Jing Zhang
2021-01-05  8:24     ` Marc Zyngier
2021-01-05  8:24       ` Marc Zyngier
2020-12-28 10:49 ` [PATCH 05/17] arm64: Initialise as nVHE before switching to VHE Marc Zyngier
2020-12-28 10:49   ` Marc Zyngier
2020-12-28 10:49 ` [PATCH 06/17] arm64: Move VHE-specific SPE setup to mutate_to_vhe() Marc Zyngier
2020-12-28 10:49   ` Marc Zyngier
2020-12-28 10:49 ` [PATCH 07/17] arm64: Simplify init_el2_state to be non-VHE only Marc Zyngier
2020-12-28 10:49   ` Marc Zyngier
2020-12-28 10:49 ` [PATCH 08/17] arm64: Move SCTLR_EL1 initialisation to EL-agnostic code Marc Zyngier
2020-12-28 10:49   ` Marc Zyngier
2020-12-28 10:49 ` Marc Zyngier [this message]
2020-12-28 10:49   ` [PATCH 09/17] arm64: cpufeature: Add global feature override facility Marc Zyngier
2020-12-28 10:49 ` [PATCH 10/17] arm64: Extract early FDT mapping from kaslr_early_init() Marc Zyngier
2020-12-28 10:49   ` Marc Zyngier
2020-12-28 10:49 ` [PATCH 11/17] arm64: cpufeature: Add an early command-line cpufeature override facility Marc Zyngier
2020-12-28 10:49   ` Marc Zyngier
2020-12-28 10:49 ` [PATCH 12/17] arm64: Allow ID_AA64MMFR1_EL1.VH to be overridden from the command line Marc Zyngier
2020-12-28 10:49   ` Marc Zyngier
2020-12-28 10:49 ` [PATCH 13/17] arm64: Honor VHE being disabled from the command-line Marc Zyngier
2020-12-28 10:49   ` Marc Zyngier
2020-12-28 10:49 ` [PATCH 14/17] arm64: Add an aliasing facility for the idreg override Marc Zyngier
2020-12-28 10:49   ` Marc Zyngier
2020-12-28 10:49 ` [PATCH 15/17] arm64: Make kvm-arm.mode={nvhe, protected} an alias of id_aa64mmfr1.vh=0 Marc Zyngier
2020-12-28 10:49   ` Marc Zyngier
2020-12-28 10:49 ` [PATCH 16/17] KVM: arm64: Document HVC_VHE_RESTART stub hypercall Marc Zyngier
2020-12-28 10:49   ` Marc Zyngier
2020-12-28 10:49 ` [PATCH 17/17] arm64: Move "nokaslr" over to the early cpufeature infrastructure Marc Zyngier
2020-12-28 10:49   ` Marc Zyngier
2020-12-29 19:27 ` [PATCH 00/17] arm64: Early CPU feature override, and an application to VHE Marc Zyngier
2020-12-29 19:27   ` Marc Zyngier

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