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From: Marc Zyngier <maz@kernel.org>
To: <kvmarm@lists.cs.columbia.edu>, <kvmarm@lists.linux.dev>,
	kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc: James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Oliver Upton <oliver.upton@linux.dev>,
	Quentin Perret <qperret@google.com>,
	Will Deacon <will@kernel.org>, Fuad Tabba <tabba@google.com>
Subject: [PATCH 01/17] arm64: Turn kaslr_feature_override into a generic SW feature override
Date: Thu, 20 Oct 2022 10:07:11 +0100	[thread overview]
Message-ID: <20221020090727.3669908-2-maz@kernel.org> (raw)
In-Reply-To: <20221020090727.3669908-1-maz@kernel.org>

Disabling KASLR from the command line is implemented as a feature
override. Repaint it slightly so that it can further be used as
more generic infrastructure for SW override purposes.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/cpufeature.h |  4 ++++
 arch/arm64/kernel/cpufeature.c      |  2 ++
 arch/arm64/kernel/idreg-override.c  | 16 ++++++----------
 arch/arm64/kernel/kaslr.c           |  6 +++---
 4 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index f73f11b55042..f44a7860636f 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -15,6 +15,8 @@
 #define MAX_CPU_FEATURES	128
 #define cpu_feature(x)		KERNEL_HWCAP_ ## x
 
+#define ARM64_SW_FEATURE_OVERRIDE_NOKASLR	0
+
 #ifndef __ASSEMBLY__
 
 #include <linux/bug.h>
@@ -914,6 +916,8 @@ extern struct arm64_ftr_override id_aa64smfr0_override;
 extern struct arm64_ftr_override id_aa64isar1_override;
 extern struct arm64_ftr_override id_aa64isar2_override;
 
+extern struct arm64_ftr_override arm64_sw_feature_override;
+
 u32 get_kvm_ipa_limit(void);
 void dump_cpu_features(void);
 
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 6062454a9067..a3959e9f7d55 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -620,6 +620,8 @@ struct arm64_ftr_override __ro_after_init id_aa64smfr0_override;
 struct arm64_ftr_override __ro_after_init id_aa64isar1_override;
 struct arm64_ftr_override __ro_after_init id_aa64isar2_override;
 
+struct arm64_ftr_override arm64_sw_feature_override;
+
 static const struct __ftr_reg_entry {
 	u32			sys_id;
 	struct arm64_ftr_reg 	*reg;
diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c
index 95133765ed29..4e8ef5e05db7 100644
--- a/arch/arm64/kernel/idreg-override.c
+++ b/arch/arm64/kernel/idreg-override.c
@@ -137,15 +137,11 @@ static const struct ftr_set_desc smfr0 __initconst = {
 	},
 };
 
-extern struct arm64_ftr_override kaslr_feature_override;
-
-static const struct ftr_set_desc kaslr __initconst = {
-	.name		= "kaslr",
-#ifdef CONFIG_RANDOMIZE_BASE
-	.override	= &kaslr_feature_override,
-#endif
+static const struct ftr_set_desc sw_features __initconst = {
+	.name		= "arm64_sw",
+	.override	= &arm64_sw_feature_override,
 	.fields		= {
-		FIELD("disabled", 0, NULL),
+		FIELD("nokaslr", ARM64_SW_FEATURE_OVERRIDE_NOKASLR, NULL),
 		{}
 	},
 };
@@ -157,7 +153,7 @@ static const struct ftr_set_desc * const regs[] __initconst = {
 	&isar1,
 	&isar2,
 	&smfr0,
-	&kaslr,
+	&sw_features,
 };
 
 static const struct {
@@ -174,7 +170,7 @@ static const struct {
 	  "id_aa64isar1.api=0 id_aa64isar1.apa=0 "
 	  "id_aa64isar2.gpa3=0 id_aa64isar2.apa3=0"	   },
 	{ "arm64.nomte",		"id_aa64pfr1.mte=0" },
-	{ "nokaslr",			"kaslr.disabled=1" },
+	{ "nokaslr",			"arm64_sw.nokaslr=1" },
 };
 
 static int __init find_field(const char *cmdline,
diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c
index 325455d16dbc..7b39283278e5 100644
--- a/arch/arm64/kernel/kaslr.c
+++ b/arch/arm64/kernel/kaslr.c
@@ -23,8 +23,6 @@
 u64 __ro_after_init module_alloc_base;
 u16 __initdata memstart_offset_seed;
 
-struct arm64_ftr_override kaslr_feature_override __initdata;
-
 static int __init kaslr_init(void)
 {
 	u64 module_range;
@@ -36,7 +34,9 @@ static int __init kaslr_init(void)
 	 */
 	module_alloc_base = (u64)_etext - MODULES_VSIZE;
 
-	if (kaslr_feature_override.val & kaslr_feature_override.mask & 0xf) {
+	if (cpuid_feature_extract_unsigned_field(arm64_sw_feature_override.val &
+						 arm64_sw_feature_override.mask,
+						 ARM64_SW_FEATURE_OVERRIDE_NOKASLR)) {
 		pr_info("KASLR disabled on command line\n");
 		return 0;
 	}
-- 
2.34.1


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  reply	other threads:[~2022-10-20  9:10 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-20  9:07 [PATCH 00/17] KVM: arm64: Allow using VHE in the nVHE hypervisor Marc Zyngier
2022-10-20  9:07 ` Marc Zyngier [this message]
2022-10-20  9:07 ` [PATCH 02/17] arm64: Add KVM_HVHE capability and has_hvhe() predicate Marc Zyngier
2023-06-01  7:01   ` Oliver Upton
2022-10-20  9:07 ` [PATCH 03/17] arm64: Don't enable VHE for the kernel if OVERRIDE_HVHE is set Marc Zyngier
2022-10-20  9:07 ` [PATCH 04/17] arm64: Prevent the use of is_kernel_in_hyp_mode() in hypervisor code Marc Zyngier
2022-10-20  9:07 ` [PATCH 05/17] arm64: Allow EL1 physical timer access when running VHE Marc Zyngier
2022-10-20  9:07 ` [PATCH 06/17] arm64: Use CPACR_EL1 format to set CPTR_EL2 when E2H is set Marc Zyngier
2022-10-20  9:07 ` [PATCH 07/17] KVM: arm64: Elide kern_hyp_va() in VHE-specific parts of the hypervisor Marc Zyngier
2022-10-20  9:07 ` [PATCH 08/17] KVM: arm64: Remove alternatives from sysreg accessors in VHE hypervisor context Marc Zyngier
2022-10-20  9:07 ` [PATCH 09/17] KVM: arm64: Key use of VHE instructions in nVHE code off ARM64_KVM_HVHE Marc Zyngier
2022-10-20  9:07 ` [PATCH 10/17] KVM: arm64: Force HCR_EL2.E2H when ARM64_KVM_HVHE is set Marc Zyngier
2022-10-20  9:07 ` [PATCH 11/17] KVM: arm64: Disable TTBR1_EL2 when using ARM64_KVM_HVHE Marc Zyngier
2022-10-20  9:07 ` [PATCH 12/17] KVM: arm64: Adjust EL2 stage-1 leaf AP bits when ARM64_KVM_HVHE is set Marc Zyngier
2022-10-20  9:07 ` [PATCH 13/17] KVM: arm64: Rework CPTR_EL2 programming for HVHE configuration Marc Zyngier
2022-10-20  9:07 ` [PATCH 14/17] KVM: arm64: Program the timer traps with VHE layout in hVHE mode Marc Zyngier
2022-10-20  9:07 ` [PATCH 15/17] KVM: arm64: Force HCR_E2H in guest context when ARM64_KVM_HVHE is set Marc Zyngier
2022-10-20  9:07 ` [PATCH 16/17] arm64: Allow arm64_sw.hvhe on command line Marc Zyngier
2022-10-20  9:07 ` [PATCH 17/17] KVM: arm64: Terrible timer hack for M1 with hVHE Marc Zyngier

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