diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 71d23b5d10d4..fc78b77e6393 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1462,6 +1462,33 @@ config ARM64_PTR_AUTH endmenu +menu "ARMv8.4 architectural features" + +config ARM64_AMU_EXTN + bool "Enable support for the Activity Monitors Unit CPU extension" + default y + help + The activity monitors extension is an optional extension introduced + by the ARMv8.4 CPU architecture. This enables support for version 1 + of the activity monitors architecture, AMUv1. + + To enable the use of this extension on CPUs that implement it, say Y. + + Note that for architectural reasons, firmware _must_ implement AMU + support when running on CPUs that present the activity monitors + extension. The required support is present in: + * Version 1.5 and later of the ARM Trusted Firmware + + For kernels that have this configuration enabled but boot with broken + firmware, you may need to say N here until the firmware is fixed. + Otherwise you may experience firmware panics or lockups when + accessing the counter registers. Even if you are not observing these + symptoms, the values returned by the register reads might not + correctly reflect reality. Most commonly, the value read will be 0, + indicating that the counter is not enabled. + +endmenu + config ARM64_SVE bool "ARM Scalable Vector Extension support" default y diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index 2bbf17419a40..9f6894df8592 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -55,8 +55,9 @@ #define ARM64_WORKAROUND_CAVIUM_TX2_219_TVM 45 #define ARM64_WORKAROUND_CAVIUM_TX2_219_PRFM 46 #define ARM64_WORKAROUND_1542419 47 +#define ARM64_HAS_AMU_EXTN 48 -/* kabi: reserve 48 - 62 for future cpu capabilities */ +/* kabi: reserve 49 - 62 for future cpu capabilities */ #define ARM64_NCAPS 62 #endif /* __ASM_CPUCAPS_H */ diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 10d3048dec7c..119f2eea7f44 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -659,6 +659,12 @@ static inline u32 id_aa64mmfr0_parange_to_phys_shift(int parange) default: return CONFIG_ARM64_PA_BITS; } } + +#ifdef CONFIG_ARM64_AMU_EXTN +/* Check whether the cpu supports the Activity Monitors Unit (AMU) */ +extern bool cpu_has_amu_feat(int cpu); +#endif + #endif /* __ASSEMBLY__ */ #endif diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index 9b68f1b3915e..dd885ba6171b 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -384,6 +384,42 @@ #define SYS_TPIDR_EL0 sys_reg(3, 3, 13, 0, 2) #define SYS_TPIDRRO_EL0 sys_reg(3, 3, 13, 0, 3) +/* Definitions for system register interface to AMU for ARMv8.4 onwards */ +#define SYS_AM_EL0(crm, op2) sys_reg(3, 3, 13, (crm), (op2)) +#define SYS_AMCR_EL0 SYS_AM_EL0(2, 0) +#define SYS_AMCFGR_EL0 SYS_AM_EL0(2, 1) +#define SYS_AMCGCR_EL0 SYS_AM_EL0(2, 2) +#define SYS_AMUSERENR_EL0 SYS_AM_EL0(2, 3) +#define SYS_AMCNTENCLR0_EL0 SYS_AM_EL0(2, 4) +#define SYS_AMCNTENSET0_EL0 SYS_AM_EL0(2, 5) +#define SYS_AMCNTENCLR1_EL0 SYS_AM_EL0(3, 0) +#define SYS_AMCNTENSET1_EL0 SYS_AM_EL0(3, 1) + +/* + * Group 0 of activity monitors (architected): + * op0 op1 CRn CRm op2 + * Counter: 11 011 1101 010:n<3> n<2:0> + * Type: 11 011 1101 011:n<3> n<2:0> + * n: 0-15 + * + * Group 1 of activity monitors (auxiliary): + * op0 op1 CRn CRm op2 + * Counter: 11 011 1101 110:n<3> n<2:0> + * Type: 11 011 1101 111:n<3> n<2:0> + * n: 0-15 + */ + +#define SYS_AMEVCNTR0_EL0(n) SYS_AM_EL0(4 + ((n) >> 3), (n) & 7) +#define SYS_AMEVTYPE0_EL0(n) SYS_AM_EL0(6 + ((n) >> 3), (n) & 7) +#define SYS_AMEVCNTR1_EL0(n) SYS_AM_EL0(12 + ((n) >> 3), (n) & 7) +#define SYS_AMEVTYPE1_EL0(n) SYS_AM_EL0(14 + ((n) >> 3), (n) & 7) + +/* AMU v1: Fixed (architecturally defined) activity monitors */ +#define SYS_AMEVCNTR0_CORE_EL0 SYS_AMEVCNTR0_EL0(0) +#define SYS_AMEVCNTR0_CONST_EL0 SYS_AMEVCNTR0_EL0(1) +#define SYS_AMEVCNTR0_INST_RET_EL0 SYS_AMEVCNTR0_EL0(2) +#define SYS_AMEVCNTR0_MEM_STALL SYS_AMEVCNTR0_EL0(3) + #define SYS_CNTFRQ_EL0 sys_reg(3, 3, 14, 0, 0) #define SYS_CNTP_TVAL_EL0 sys_reg(3, 3, 14, 2, 0) @@ -579,6 +615,7 @@ #define ID_AA64PFR0_CSV3_SHIFT 60 #define ID_AA64PFR0_CSV2_SHIFT 56 #define ID_AA64PFR0_DIT_SHIFT 48 +#define ID_AA64PFR0_AMU_SHIFT 44 #define ID_AA64PFR0_SVE_SHIFT 32 #define ID_AA64PFR0_RAS_SHIFT 28 #define ID_AA64PFR0_GIC_SHIFT 24 @@ -589,6 +626,7 @@ #define ID_AA64PFR0_EL1_SHIFT 4 #define ID_AA64PFR0_EL0_SHIFT 0 +#define ID_AA64PFR0_AMU 0x1 #define ID_AA64PFR0_SVE 0x1 #define ID_AA64PFR0_RAS_V1 0x1 #define ID_AA64PFR0_FP_NI 0xf diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index da92693b202c..63efa52dea67 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -154,6 +154,7 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = { ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_CSV3_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_CSV2_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_DIT_SHIFT, 4, 0), + ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_AMU_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE), FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_SVE_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR0_RAS_SHIFT, 4, 0), @@ -1147,6 +1148,53 @@ static bool has_hw_dbm(const struct arm64_cpu_capabilities *cap, #endif +#ifdef CONFIG_ARM64_AMU_EXTN + +/* + * The "amu_cpus" cpumask only signals that the CPU implementation for the + * flagged CPUs supports the Activity Monitors Unit (AMU) but does not provide + * information regarding all the events that it supports. When a CPU bit is + * set in the cpumask, the user of this feature can only rely on the presence + * of the 4 fixed counters for that CPU. But this does not guarantee that the + * counters are enabled or access to these counters is enabled by code + * executed at higher exception levels (firmware). + */ +static struct cpumask amu_cpus __read_mostly; + +bool cpu_has_amu_feat(int cpu) +{ + return cpumask_test_cpu(cpu, &amu_cpus); +} + +static void cpu_amu_enable(struct arm64_cpu_capabilities const *cap) +{ + if (has_cpuid_feature(cap, SCOPE_LOCAL_CPU)) { + pr_info("detected CPU%d: Activity Monitors Unit (AMU)\n", + smp_processor_id()); + cpumask_set_cpu(smp_processor_id(), &amu_cpus); + } +} + +static bool has_amu(const struct arm64_cpu_capabilities *cap, + int __unused) +{ + /* + * The AMU extension is a non-conflicting feature: the kernel can + * safely run a mix of CPUs with and without support for the + * activity monitors extension. Therefore, unconditionally enable + * the capability to allow any late CPU to use the feature. + * + * With this feature unconditionally enabled, the cpu_enable + * function will be called for all CPUs that match the criteria, + * including secondary and hotplugged, marking this feature as + * present on that respective CPU. The enable function will also + * print a detection message. + */ + + return true; +} +#endif + #ifdef CONFIG_ARM64_VHE static bool runs_at_el2(const struct arm64_cpu_capabilities *entry, int __unused) { @@ -1416,6 +1464,24 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .cpu_enable = cpu_clear_disr, }, #endif /* CONFIG_ARM64_RAS_EXTN */ +#ifdef CONFIG_ARM64_AMU_EXTN + { + /* + * The feature is enabled by default if CONFIG_ARM64_AMU_EXTN=y. + * Therefore, don't provide .desc as we don't want the detection + * message to be shown until at least one CPU is detected to + * support the feature. + */ + .capability = ARM64_HAS_AMU_EXTN, + .type = ARM64_CPUCAP_WEAK_LOCAL_CPU_FEATURE, + .matches = has_amu, + .sys_reg = SYS_ID_AA64PFR0_EL1, + .sign = FTR_UNSIGNED, + .field_pos = ID_AA64PFR0_AMU_SHIFT, + .min_field_value = ID_AA64PFR0_AMU, + .cpu_enable = cpu_amu_enable, + }, +#endif /* CONFIG_ARM64_AMU_EXTN */ { .desc = "Data cache clean to the PoU not required for I/D coherence", .capability = ARM64_HAS_CACHE_IDC,