| Message ID | 20210728094302.9949-2-yee.lee@mediatek.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64/cpufeature: Add an option for mte support | expand |
On 28/07/2021 10:42, yee.lee@mediatek.com wrote: > From: Yee Lee <yee.lee@mediatek.com> > > Add a static key to exapnd the logic of system_supports_mte(). > This function controls mte enablement in both EL1 and EL0. > > The static key, "arm64_mte_support" is default true and can > be disabled via the early_param. Please could we use the id-reg override mechanism and give it an alias ? See : arch/arm64/kernel/idreg-override.c And could add something along the lines of : arm64.nomte Cheers Suzuki
On Wed, 28 Jul 2021 10:42:58 +0100, <yee.lee@mediatek.com> wrote: > > From: Yee Lee <yee.lee@mediatek.com> > > Add a static key to exapnd the logic of system_supports_mte(). > This function controls mte enablement in both EL1 and EL0. > > The static key, "arm64_mte_support" is default true and can > be disabled via the early_param. > > Signed-off-by: Yee Lee <yee.lee@mediatek.com> > --- > arch/arm64/include/asm/cpufeature.h | 4 +++- > arch/arm64/kernel/cpufeature.c | 13 +++++++++++++ > arch/arm64/kernel/image-vars.h | 3 +++ > 3 files changed, 19 insertions(+), 1 deletion(-) This seems terribly complicated. How about this instead ("arm64.nomte" on the command line)? Thanks, M. diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c index 53a381a7f65d..eaf17beb2420 100644 --- a/arch/arm64/kernel/idreg-override.c +++ b/arch/arm64/kernel/idreg-override.c @@ -54,6 +54,7 @@ static const struct ftr_set_desc pfr1 __initconst = { .override = &id_aa64pfr1_override, .fields = { { "bt", ID_AA64PFR1_BT_SHIFT }, + { "mte", ID_AA64PFR1_MTE_SHIFT }, {} }, }; @@ -100,6 +101,7 @@ static const struct { { "arm64.nopauth", "id_aa64isar1.gpi=0 id_aa64isar1.gpa=0 " "id_aa64isar1.api=0 id_aa64isar1.apa=0" }, + { "arm64.nomte", "id_aa64pfr1.mte=0" }, { "nokaslr", "kaslr.disabled=1" }, };
On Wed, 28 Jul 2021 10:59:24 +0100, Suzuki K Poulose <suzuki.poulose@arm.com> wrote: > > On 28/07/2021 10:42, yee.lee@mediatek.com wrote: > > From: Yee Lee <yee.lee@mediatek.com> > > > > Add a static key to exapnd the logic of system_supports_mte(). > > This function controls mte enablement in both EL1 and EL0. > > > > The static key, "arm64_mte_support" is default true and can > > be disabled via the early_param. > > Please could we use the id-reg override mechanism and give it > an alias ? > > See : > > arch/arm64/kernel/idreg-override.c > > And could add something along the lines of : > > arm64.nomte Damn, you beat me to it! :D M.
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 9bb9d11750d7..0e5c82f2e012 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -420,6 +420,7 @@ static __always_inline bool is_hyp_code(void) extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS); extern struct static_key_false cpu_hwcap_keys[ARM64_NCAPS]; extern struct static_key_false arm64_const_caps_ready; +extern struct static_key_true arm64_mte_support; /* ARM64 CAPS + alternative_cb */ #define ARM64_NPATCHABLE (ARM64_NCAPS + 1) @@ -756,7 +757,8 @@ static __always_inline bool system_uses_irq_prio_masking(void) static inline bool system_supports_mte(void) { return IS_ENABLED(CONFIG_ARM64_MTE) && - cpus_have_const_cap(ARM64_MTE); + cpus_have_const_cap(ARM64_MTE) && + static_branch_likely(&arm64_mte_support); } static inline bool system_has_prio_mask_debugging(void) diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 0ead8bfedf20..b1602ad3d7c0 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1840,9 +1840,22 @@ static void bti_enable(const struct arm64_cpu_capabilities *__unused) } #endif /* CONFIG_ARM64_BTI */ +DEFINE_STATIC_KEY_TRUE(arm64_mte_support); +EXPORT_SYMBOL(arm64_mte_support); #ifdef CONFIG_ARM64_MTE +static int __init disable_arm64_mte_support(char *str) +{ + static_branch_disable(&arm64_mte_support); + return 0; +} +early_param("arm64_mte_not_support", disable_arm64_mte_support); + static void cpu_enable_mte(struct arm64_cpu_capabilities const *cap) { + if(!system_supports_mte()){ + pr_info("MTE is disabled since system does not support.\n"); + return ; + } /* * Clear the tags in the zero page. This needs to be done via the * linear map which has the Tagged attribute. diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h index c96a9a0043bf..04cf30ec84e7 100644 --- a/arch/arm64/kernel/image-vars.h +++ b/arch/arm64/kernel/image-vars.h @@ -83,6 +83,9 @@ KVM_NVHE_ALIAS(__icache_flags); KVM_NVHE_ALIAS(arm64_const_caps_ready); KVM_NVHE_ALIAS(cpu_hwcap_keys); +/* Static key which indicates if system supports mte */ +KVM_NVHE_ALIAS(arm64_mte_support); + /* Static keys which are set if a vGIC trap should be handled in hyp. */ KVM_NVHE_ALIAS(vgic_v2_cpuif_trap); KVM_NVHE_ALIAS(vgic_v3_cpuif_trap);