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
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next prev parent reply other threads:[~2020-12-28 10:50 UTC|newest]
Thread overview: 21+ 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 ` [PATCH 01/17] arm64: Fix labels in el2_setup macros Marc Zyngier
2020-12-28 10:49 ` [PATCH 02/17] arm64: Fix outdated TCR setup comment 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 ` [PATCH 04/17] arm64: Provide an 'upgrade to VHE' stub hypercall Marc Zyngier
2021-01-04 23:39 ` Jing Zhang
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 ` [PATCH 06/17] arm64: Move VHE-specific SPE setup to mutate_to_vhe() 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 ` [PATCH 08/17] arm64: Move SCTLR_EL1 initialisation to EL-agnostic code Marc Zyngier
2020-12-28 10:49 ` Marc Zyngier [this message]
2020-12-28 10:49 ` [PATCH 10/17] arm64: Extract early FDT mapping from kaslr_early_init() 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 ` [PATCH 12/17] arm64: Allow ID_AA64MMFR1_EL1.VH to be overridden from the command line 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 ` [PATCH 14/17] arm64: Add an aliasing facility for the idreg override 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 ` [PATCH 16/17] KVM: arm64: Document HVC_VHE_RESTART stub hypercall Marc Zyngier
2020-12-28 10:49 ` [PATCH 17/17] arm64: Move "nokaslr" over to the early cpufeature infrastructure Marc Zyngier
2020-12-29 19:27 ` [PATCH 00/17] arm64: Early CPU feature override, and an application to VHE Marc Zyngier
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