From: Catalin Marinas <catalin.marinas@arm.com> mainline inclusion from mainline-v6.17-rc1 commit 3eb06f6ce3af65df4e9b3d8fc1d711fbfe7673b3 category: feature bugzilla: https://atomgit.com/openeuler/kernel/issues/9850 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ------------------------------------------- For system-wide capabilities, the kernel has the SCOPE_SYSTEM type. Such capabilities are checked once the SMP boot has completed using the sanitised ID registers. However, there is a need for a new capability type similar in scope to the system one but with checking performed locally on each CPU during boot (e.g. based on MIDR_EL1 which is not a sanitised register). Introduce ARM64_CPUCAP_MATCH_ALL_EARLY_CPUS which, together with ARM64_CPUCAP_SCOPE_LOCAL_CPU, ensures that such capability is enabled only if all early CPUs have it. For ease of use, define ARM64_CPUCAP_EARLY_LOCAL_CPU_FEATURE which combines SCOPE_LOCAL_CPU, PERMITTED_FOR_LATE_CPUS and MATCH_ALL_EARLY_CPUS. Signed-off-by: Mikołaj Lenczewski <miko.lenczewski@arm.com> Reviewed-by: Suzuki K Poulose <Suzuki.Poulose@arm.com> Link: https://lore.kernel.org/r/20250625113435.26849-2-miko.lenczewski@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Conflicts: arch/arm64/kernel/cpufeature.c [Context conflicts.] Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com> --- arch/arm64/include/asm/cpufeature.h | 23 ++++++++++++ arch/arm64/kernel/cpufeature.c | 56 +++++++++++++++++++++++++---- 2 files changed, 72 insertions(+), 7 deletions(-) diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 4640017419d1..c68cf7569d15 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -274,6 +274,14 @@ extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0; #define ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU ((u16)BIT(5)) /* Panic when a conflict is detected */ #define ARM64_CPUCAP_PANIC_ON_CONFLICT ((u16)BIT(6)) +/* + * When paired with SCOPE_LOCAL_CPU, all early CPUs must satisfy the + * condition. This is different from SCOPE_SYSTEM where the check is performed + * only once at the end of the SMP boot on the sanitised ID registers. + * SCOPE_SYSTEM is not suitable for cases where the capability depends on + * properties local to a CPU like MIDR_EL1. + */ +#define ARM64_CPUCAP_MATCH_ALL_EARLY_CPUS ((u16)BIT(7)) /* * CPU errata workarounds that need to be enabled at boot time if one or @@ -303,6 +311,16 @@ extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0; (ARM64_CPUCAP_SCOPE_LOCAL_CPU | \ ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU | \ ARM64_CPUCAP_PERMITTED_FOR_LATE_CPU) +/* + * CPU feature detected at boot time and present on all early CPUs. Late CPUs + * are permitted to have the feature even if it hasn't been enabled, although + * the feature will not be used by Linux in this case. If all early CPUs have + * the feature, then every late CPU must have it. + */ +#define ARM64_CPUCAP_EARLY_LOCAL_CPU_FEATURE \ + (ARM64_CPUCAP_SCOPE_LOCAL_CPU | \ + ARM64_CPUCAP_PERMITTED_FOR_LATE_CPU | \ + ARM64_CPUCAP_MATCH_ALL_EARLY_CPUS) /* * CPU feature detected at boot time, on one or more CPUs. A late CPU @@ -389,6 +407,11 @@ static inline int cpucap_default_scope(const struct arm64_cpu_capabilities *cap) return cap->type & ARM64_CPUCAP_SCOPE_MASK; } +static inline bool cpucap_match_all_early_cpus(const struct arm64_cpu_capabilities *cap) +{ + return cap->type & ARM64_CPUCAP_MATCH_ALL_EARLY_CPUS; +} + /* * Generic helper for handling capabilities with multiple (match,enable) pairs * of call backs, sharing the same capability bit. diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 4a814db14cbd..a2297259a82d 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -3586,18 +3586,49 @@ static void update_cpu_capabilities(u16 scope_mask) scope_mask &= ARM64_CPUCAP_SCOPE_MASK; for (i = 0; i < ARM64_NCAPS; i++) { + bool match_all = false; + bool caps_set = false; + bool boot_cpu = false; + caps = cpucap_ptrs[i]; - if (!caps || !(caps->type & scope_mask) || - cpus_have_cap(caps->capability) || - !caps->matches(caps, cpucap_default_scope(caps))) + if (!caps || !(caps->type & scope_mask)) + continue; + + match_all = cpucap_match_all_early_cpus(caps); + caps_set = cpus_have_cap(caps->capability); + boot_cpu = scope_mask & SCOPE_BOOT_CPU; + + /* + * Unless it's a match-all CPUs feature, avoid probing if + * already detected. + */ + if (!match_all && caps_set) + continue; + + /* + * A match-all CPUs capability is only set when probing the + * boot CPU. It may be cleared subsequently if not detected on + * secondary ones. + */ + if (match_all && !caps_set && !boot_cpu) continue; - if (caps->desc && !caps->cpus) + if (!caps->matches(caps, cpucap_default_scope(caps))) { + if (match_all) + __clear_bit(caps->capability, system_cpucaps); + continue; + } + + /* + * Match-all CPUs capabilities are logged later when the + * system capabilities are finalised. + */ + if (!match_all && caps->desc && !caps->cpus) pr_info("detected: %s\n", caps->desc); __set_bit(caps->capability, system_cpucaps); - if ((scope_mask & SCOPE_BOOT_CPU) && (caps->type & SCOPE_BOOT_CPU)) + if (boot_cpu && (caps->type & SCOPE_BOOT_CPU)) set_bit(caps->capability, boot_cpucaps); } } @@ -3961,10 +3992,21 @@ static void __init setup_system_capabilities(void) for (i = 0; i < ARM64_NCAPS; i++) { const struct arm64_cpu_capabilities *caps = cpucap_ptrs[i]; - if (caps && caps->cpus && caps->desc && - cpumask_any(caps->cpus) < nr_cpu_ids) + if (!caps || !caps->desc) + continue; + + /* + * Log any cpucaps with a cpumask as these aren't logged by + * update_cpu_capabilities(). + */ + if (caps->cpus && cpumask_any(caps->cpus) < nr_cpu_ids) pr_info("detected: %s on CPU%*pbl\n", caps->desc, cpumask_pr_args(caps->cpus)); + + /* Log match-all CPUs capabilities */ + if (cpucap_match_all_early_cpus(caps) && + cpus_have_cap(caps->capability)) + pr_info("detected: %s\n", caps->desc); } } -- 2.43.0