From de66cb37ab6488d78d4b415504ad1fcd0910bae5 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 16 Oct 2023 11:24:27 +0100 Subject: [PATCH] arm64: Add cpucap_is_possible() Many cpucaps can only be set when certain CONFIG_* options are selected, and we need to check the CONFIG_* option before the cap in order to avoid generating redundant code. Due to this, we have a growing number of helpers in of the form: | static __always_inline bool system_supports_foo(void) | { | return IS_ENABLED(CONFIG_ARM64_FOO) && | cpus_have_const_cap(ARM64_HAS_FOO); | } This is unfortunate as it forces us to use cpus_have_const_cap() unnecessarily, resulting in redundant code being generated by the compiler. In the vast majority of cases, we only require that feature checks indicate the presence of a feature after cpucaps have been finalized, and so it would be sufficient to use alternative_has_cap_*(). However some code needs to handle a feature before alternatives have been patched, and must test the system_cpucaps bitmap via cpus_have_const_cap(). In other cases we'd like to check for unintentional usage of a cpucap before alternatives are patched, and so it would be preferable to use cpus_have_final_cap(). Placing the IS_ENABLED() checks in each callsite is tedious and error-prone, and the same applies for writing wrappers for each comination of cpucap and alternative_has_cap_*() / cpus_have_cap() / cpus_have_final_cap(). It would be nicer if we could centralize the knowledge of which cpucaps are possible, and have alternative_has_cap_*(), cpus_have_cap(), and cpus_have_final_cap() handle this automatically. This patch adds a new cpucap_is_possible() function which will be responsible for checking the CONFIG_* option, and updates the low-level cpucap checks to use this. The existing CONFIG_* checks in are moved over to cpucap_is_possible(), but the (now trival) wrapper functions are retained for now. There should be no functional change as a result of this patch alone. Signed-off-by: Mark Rutland Cc: Marc Zyngier Cc: Mark Brown Cc: Suzuki K Poulose Cc: Will Deacon Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/alternative-macros.h | 8 ++-- arch/arm64/include/asm/cpucaps.h | 41 +++++++++++++++++++++ arch/arm64/include/asm/cpufeature.h | 39 +++++++------------- 3 files changed, 59 insertions(+), 29 deletions(-) diff --git a/arch/arm64/include/asm/alternative-macros.h b/arch/arm64/include/asm/alternative-macros.h index 94b486192e1f1..210bb43cff2c7 100644 --- a/arch/arm64/include/asm/alternative-macros.h +++ b/arch/arm64/include/asm/alternative-macros.h @@ -226,8 +226,8 @@ alternative_endif static __always_inline bool alternative_has_cap_likely(const unsigned long cpucap) { - compiletime_assert(cpucap < ARM64_NCAPS, - "cpucap must be < ARM64_NCAPS"); + if (!cpucap_is_possible(cpucap)) + return false; asm_volatile_goto( ALTERNATIVE_CB("b %l[l_no]", %[cpucap], alt_cb_patch_nops) @@ -244,8 +244,8 @@ l_no: static __always_inline bool alternative_has_cap_unlikely(const unsigned long cpucap) { - compiletime_assert(cpucap < ARM64_NCAPS, - "cpucap must be < ARM64_NCAPS"); + if (!cpucap_is_possible(cpucap)) + return false; asm_volatile_goto( ALTERNATIVE("nop", "b %l[l_yes]", %[cpucap]) diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index 7333b5bbf4488..764ad4eef8591 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -5,4 +5,45 @@ #include +#ifndef __ASSEMBLY__ +#include +/* + * Check whether a cpucap is possible at compiletime. + */ +static __always_inline bool +cpucap_is_possible(const unsigned int cap) +{ + compiletime_assert(__builtin_constant_p(cap), + "cap must be a constant"); + compiletime_assert(cap < ARM64_NCAPS, + "cap must be < ARM64_NCAPS"); + + switch (cap) { + case ARM64_HAS_PAN: + return IS_ENABLED(CONFIG_ARM64_PAN); + case ARM64_SVE: + return IS_ENABLED(CONFIG_ARM64_SVE); + case ARM64_SME: + case ARM64_SME2: + case ARM64_SME_FA64: + return IS_ENABLED(CONFIG_ARM64_SME); + case ARM64_HAS_CNP: + return IS_ENABLED(CONFIG_ARM64_CNP); + case ARM64_HAS_ADDRESS_AUTH: + case ARM64_HAS_GENERIC_AUTH: + return IS_ENABLED(CONFIG_ARM64_PTR_AUTH); + case ARM64_HAS_GIC_PRIO_MASKING: + return IS_ENABLED(CONFIG_ARM64_PSEUDO_NMI); + case ARM64_MTE: + return IS_ENABLED(CONFIG_ARM64_MTE); + case ARM64_BTI: + return IS_ENABLED(CONFIG_ARM64_BTI); + case ARM64_HAS_TLB_RANGE: + return IS_ENABLED(CONFIG_ARM64_TLB_RANGE); + } + + return true; +} +#endif /* __ASSEMBLY__ */ + #endif /* __ASM_CPUCAPS_H */ diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 5bba393760557..577d9766e5abc 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -450,6 +450,8 @@ static __always_inline bool system_capabilities_finalized(void) */ static __always_inline bool cpus_have_cap(unsigned int num) { + if (__builtin_constant_p(num) && !cpucap_is_possible(num)) + return false; if (num >= ARM64_NCAPS) return false; return arch_test_bit(num, system_cpucaps); @@ -465,8 +467,6 @@ static __always_inline bool cpus_have_cap(unsigned int num) */ static __always_inline bool __cpus_have_const_cap(int num) { - if (num >= ARM64_NCAPS) - return false; return alternative_has_cap_unlikely(num); } @@ -740,8 +740,7 @@ static __always_inline bool system_supports_fpsimd(void) static inline bool system_uses_hw_pan(void) { - return IS_ENABLED(CONFIG_ARM64_PAN) && - cpus_have_const_cap(ARM64_HAS_PAN); + return cpus_have_const_cap(ARM64_HAS_PAN); } static inline bool system_uses_ttbr0_pan(void) @@ -752,26 +751,22 @@ static inline bool system_uses_ttbr0_pan(void) static __always_inline bool system_supports_sve(void) { - return IS_ENABLED(CONFIG_ARM64_SVE) && - cpus_have_const_cap(ARM64_SVE); + return cpus_have_const_cap(ARM64_SVE); } static __always_inline bool system_supports_sme(void) { - return IS_ENABLED(CONFIG_ARM64_SME) && - cpus_have_const_cap(ARM64_SME); + return cpus_have_const_cap(ARM64_SME); } static __always_inline bool system_supports_sme2(void) { - return IS_ENABLED(CONFIG_ARM64_SME) && - cpus_have_const_cap(ARM64_SME2); + return cpus_have_const_cap(ARM64_SME2); } static __always_inline bool system_supports_fa64(void) { - return IS_ENABLED(CONFIG_ARM64_SME) && - cpus_have_const_cap(ARM64_SME_FA64); + return cpus_have_const_cap(ARM64_SME_FA64); } static __always_inline bool system_supports_tpidr2(void) @@ -781,20 +776,17 @@ static __always_inline bool system_supports_tpidr2(void) static __always_inline bool system_supports_cnp(void) { - return IS_ENABLED(CONFIG_ARM64_CNP) && - cpus_have_const_cap(ARM64_HAS_CNP); + return cpus_have_const_cap(ARM64_HAS_CNP); } static inline bool system_supports_address_auth(void) { - return IS_ENABLED(CONFIG_ARM64_PTR_AUTH) && - cpus_have_const_cap(ARM64_HAS_ADDRESS_AUTH); + return cpus_have_const_cap(ARM64_HAS_ADDRESS_AUTH); } static inline bool system_supports_generic_auth(void) { - return IS_ENABLED(CONFIG_ARM64_PTR_AUTH) && - cpus_have_const_cap(ARM64_HAS_GENERIC_AUTH); + return cpus_have_const_cap(ARM64_HAS_GENERIC_AUTH); } static inline bool system_has_full_ptr_auth(void) @@ -804,14 +796,12 @@ static inline bool system_has_full_ptr_auth(void) static __always_inline bool system_uses_irq_prio_masking(void) { - return IS_ENABLED(CONFIG_ARM64_PSEUDO_NMI) && - cpus_have_const_cap(ARM64_HAS_GIC_PRIO_MASKING); + return cpus_have_const_cap(ARM64_HAS_GIC_PRIO_MASKING); } static inline bool system_supports_mte(void) { - return IS_ENABLED(CONFIG_ARM64_MTE) && - cpus_have_const_cap(ARM64_MTE); + return cpus_have_const_cap(ARM64_MTE); } static inline bool system_has_prio_mask_debugging(void) @@ -822,13 +812,12 @@ static inline bool system_has_prio_mask_debugging(void) static inline bool system_supports_bti(void) { - return IS_ENABLED(CONFIG_ARM64_BTI) && cpus_have_const_cap(ARM64_BTI); + return cpus_have_const_cap(ARM64_BTI); } static inline bool system_supports_tlb_range(void) { - return IS_ENABLED(CONFIG_ARM64_TLB_RANGE) && - cpus_have_const_cap(ARM64_HAS_TLB_RANGE); + return cpus_have_const_cap(ARM64_HAS_TLB_RANGE); } int do_emulate_mrs(struct pt_regs *regs, u32 sys_reg, u32 rt); -- 2.30.2