Messages in this thread Patch in this message | | | From | Ard Biesheuvel <> | Subject | [PATCH v3 12/60] arm64: Turn kaslr_feature_override into a generic SW feature override | Date | Tue, 7 Mar 2023 15:04:34 +0100 |
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From: Marc Zyngier <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> [ardb: don't apply the override mask to val] Signed-off-by: Ard Biesheuvel <ardb@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 | 5 ++--- 4 files changed, 14 insertions(+), 13 deletions(-)
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 6bf013fb110d7923..bc10098901808c00 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> @@ -925,6 +927,8 @@ 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 e9a138b7e3b22cc7..88cec6c14743c4c5 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -657,6 +657,8 @@ 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 d833d78a7f313563..434703e4e55cb785 100644 --- a/arch/arm64/kernel/idreg-override.c +++ b/arch/arm64/kernel/idreg-override.c @@ -138,15 +138,11 @@ 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), {} }, }; @@ -158,7 +154,7 @@ static const struct ftr_set_desc * const regs[] __initconst = { &isar1, &isar2, &smfr0, - &kaslr, + &sw_features, }; static const struct { @@ -175,7 +171,7 @@ 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 e7477f21a4c9d062..abcd996c747b8c97 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 +34,8 @@ 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_NOKASLR)) { pr_info("KASLR disabled on command line\n"); return 0; } -- 2.39.2
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