diff options
28 files changed, 712 insertions, 14 deletions
diff --git a/Documentation/riscv/hwprobe.rst b/Documentation/riscv/hwprobe.rst new file mode 100644 index 000000000000..9f0dd62dcb5d --- /dev/null +++ b/Documentation/riscv/hwprobe.rst @@ -0,0 +1,86 @@ +.. SPDX-License-Identifier: GPL-2.0 + +RISC-V Hardware Probing Interface +--------------------------------- + +The RISC-V hardware probing interface is based around a single syscall, which +is defined in <asm/hwprobe.h>:: + + struct riscv_hwprobe { + __s64 key; + __u64 value; + }; + + long sys_riscv_hwprobe(struct riscv_hwprobe *pairs, size_t pair_count, + size_t cpu_count, cpu_set_t *cpus, + unsigned int flags); + +The arguments are split into three groups: an array of key-value pairs, a CPU +set, and some flags. The key-value pairs are supplied with a count. Userspace +must prepopulate the key field for each element, and the kernel will fill in the +value if the key is recognized. If a key is unknown to the kernel, its key field +will be cleared to -1, and its value set to 0. The CPU set is defined by +CPU_SET(3). For value-like keys (eg. vendor/arch/impl), the returned value will +be only be valid if all CPUs in the given set have the same value. Otherwise -1 +will be returned. For boolean-like keys, the value returned will be a logical +AND of the values for the specified CPUs. Usermode can supply NULL for cpus and +0 for cpu_count as a shortcut for all online CPUs. There are currently no flags, +this value must be zero for future compatibility. + +On success 0 is returned, on failure a negative error code is returned. + +The following keys are defined: + +* :c:macro:`RISCV_HWPROBE_KEY_MVENDORID`: Contains the value of ``mvendorid``, + as defined by the RISC-V privileged architecture specification. + +* :c:macro:`RISCV_HWPROBE_KEY_MARCHID`: Contains the value of ``marchid``, as + defined by the RISC-V privileged architecture specification. + +* :c:macro:`RISCV_HWPROBE_KEY_MIMPLID`: Contains the value of ``mimplid``, as + defined by the RISC-V privileged architecture specification. + +* :c:macro:`RISCV_HWPROBE_KEY_BASE_BEHAVIOR`: A bitmask containing the base + user-visible behavior that this kernel supports. The following base user ABIs + are defined: + + * :c:macro:`RISCV_HWPROBE_BASE_BEHAVIOR_IMA`: Support for rv32ima or + rv64ima, as defined by version 2.2 of the user ISA and version 1.10 of the + privileged ISA, with the following known exceptions (more exceptions may be + added, but only if it can be demonstrated that the user ABI is not broken): + + * The :fence.i: instruction cannot be directly executed by userspace + programs (it may still be executed in userspace via a + kernel-controlled mechanism such as the vDSO). + +* :c:macro:`RISCV_HWPROBE_KEY_IMA_EXT_0`: A bitmask containing the extensions + that are compatible with the :c:macro:`RISCV_HWPROBE_BASE_BEHAVIOR_IMA`: + base system behavior. + + * :c:macro:`RISCV_HWPROBE_IMA_FD`: The F and D extensions are supported, as + defined by commit cd20cee ("FMIN/FMAX now implement + minimumNumber/maximumNumber, not minNum/maxNum") of the RISC-V ISA manual. + + * :c:macro:`RISCV_HWPROBE_IMA_C`: The C extension is supported, as defined + by version 2.2 of the RISC-V ISA manual. + +* :c:macro:`RISCV_HWPROBE_KEY_CPUPERF_0`: A bitmask that contains performance + information about the selected set of processors. + + * :c:macro:`RISCV_HWPROBE_MISALIGNED_UNKNOWN`: The performance of misaligned + accesses is unknown. + + * :c:macro:`RISCV_HWPROBE_MISALIGNED_EMULATED`: Misaligned accesses are + emulated via software, either in or below the kernel. These accesses are + always extremely slow. + + * :c:macro:`RISCV_HWPROBE_MISALIGNED_SLOW`: Misaligned accesses are supported + in hardware, but are slower than the cooresponding aligned accesses + sequences. + + * :c:macro:`RISCV_HWPROBE_MISALIGNED_FAST`: Misaligned accesses are supported + in hardware and are faster than the cooresponding aligned accesses + sequences. + + * :c:macro:`RISCV_HWPROBE_MISALIGNED_UNSUPPORTED`: Misaligned accesses are + not supported at all and will generate a misaligned address fault. diff --git a/Documentation/riscv/index.rst b/Documentation/riscv/index.rst index 2e5b18fbb145..175a91db0200 100644 --- a/Documentation/riscv/index.rst +++ b/Documentation/riscv/index.rst @@ -7,6 +7,7 @@ RISC-V architecture boot-image-header vm-layout + hwprobe patch-acceptance uabi diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index cc02eb9eee1f..aaa11fb48b86 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -33,6 +33,7 @@ config RISCV select ARCH_HAS_STRICT_MODULE_RWX if MMU && !XIP_KERNEL select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST select ARCH_HAS_UBSAN_SANITIZE_ALL + select ARCH_HAS_VDSO_DATA select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT select ARCH_STACKWALK diff --git a/arch/riscv/errata/thead/errata.c b/arch/riscv/errata/thead/errata.c index 7e8d50ebb71a..1036b8f933ec 100644 --- a/arch/riscv/errata/thead/errata.c +++ b/arch/riscv/errata/thead/errata.c @@ -11,7 +11,9 @@ #include <linux/uaccess.h> #include <asm/alternative.h> #include <asm/cacheflush.h> +#include <asm/cpufeature.h> #include <asm/errata_list.h> +#include <asm/hwprobe.h> #include <asm/patch.h> #include <asm/vendorid_list.h> @@ -115,3 +117,11 @@ void __init_or_module thead_errata_patch_func(struct alt_entry *begin, struct al if (stage == RISCV_ALTERNATIVES_EARLY_BOOT) local_flush_icache_all(); } + +void __init_or_module thead_feature_probe_func(unsigned int cpu, + unsigned long archid, + unsigned long impid) +{ + if ((archid == 0) && (impid == 0)) + per_cpu(misaligned_access_speed, cpu) = RISCV_HWPROBE_MISALIGNED_FAST; +} diff --git a/arch/riscv/include/asm/alternative.h b/arch/riscv/include/asm/alternative.h index 58ccd2f8cab7..a8f5cf6694a1 100644 --- a/arch/riscv/include/asm/alternative.h +++ b/arch/riscv/include/asm/alternative.h @@ -30,6 +30,7 @@ #define ALT_OLD_PTR(a) __ALT_PTR(a, old_offset) #define ALT_ALT_PTR(a) __ALT_PTR(a, alt_offset) +void __init probe_vendor_features(unsigned int cpu); void __init apply_boot_alternatives(void); void __init apply_early_boot_alternatives(void); void apply_module_alternatives(void *start, size_t length); @@ -52,11 +53,15 @@ void thead_errata_patch_func(struct alt_entry *begin, struct alt_entry *end, unsigned long archid, unsigned long impid, unsigned int stage); +void thead_feature_probe_func(unsigned int cpu, unsigned long archid, + unsigned long impid); + void riscv_cpufeature_patch_func(struct alt_entry *begin, struct alt_entry *end, unsigned int stage); #else /* CONFIG_RISCV_ALTERNATIVE */ +static inline void probe_vendor_features(unsigned int cpu) { } static inline void apply_boot_alternatives(void) { } static inline void apply_early_boot_alternatives(void) { } static inline void apply_module_alternatives(void *start, size_t length) { } diff --git a/arch/riscv/include/asm/cpufeature.h b/arch/riscv/include/asm/cpufeature.h new file mode 100644 index 000000000000..808d5403f2ac --- /dev/null +++ b/arch/riscv/include/asm/cpufeature.h @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright 2022-2023 Rivos, Inc + */ + +#ifndef _ASM_CPUFEATURE_H +#define _ASM_CPUFEATURE_H + +/* + * These are probed via a device_initcall(), via either the SBI or directly + * from the corresponding CSRs. + */ +struct riscv_cpuinfo { + unsigned long mvendorid; + unsigned long marchid; + unsigned long mimpid; +}; + +DECLARE_PER_CPU(struct riscv_cpuinfo, riscv_cpuinfo); + +DECLARE_PER_CPU(long, misaligned_access_speed); + +#endif diff --git a/arch/riscv/include/asm/hwprobe.h b/arch/riscv/include/asm/hwprobe.h new file mode 100644 index 000000000000..78936f4ff513 --- /dev/null +++ b/arch/riscv/include/asm/hwprobe.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Copyright 2023 Rivos, Inc + */ + +#ifndef _ASM_HWPROBE_H +#define _ASM_HWPROBE_H + +#include <uapi/asm/hwprobe.h> + +#define RISCV_HWPROBE_MAX_KEY 5 + +#endif diff --git a/arch/riscv/include/asm/syscall.h b/arch/riscv/include/asm/syscall.h index 736110e1fd78..0148c6bd9675 100644 --- a/arch/riscv/include/asm/syscall.h +++ b/arch/riscv/include/asm/syscall.h @@ -10,6 +10,7 @@ #ifndef _ASM_RISCV_SYSCALL_H #define _ASM_RISCV_SYSCALL_H +#include <asm/hwprobe.h> #include <uapi/linux/audit.h> #include <linux/sched.h> #include <linux/err.h> @@ -96,4 +97,7 @@ static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs) } asmlinkage long sys_riscv_flush_icache(uintptr_t, uintptr_t, uintptr_t); + +asmlinkage long sys_riscv_hwprobe(struct riscv_hwprobe *, size_t, size_t, + unsigned long *, unsigned int); #endif /* _ASM_RISCV_SYSCALL_H */ diff --git a/arch/riscv/include/asm/vdso/data.h b/arch/riscv/include/asm/vdso/data.h new file mode 100644 index 000000000000..dc2f76f58b76 --- /dev/null +++ b/arch/riscv/include/asm/vdso/data.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __RISCV_ASM_VDSO_DATA_H +#define __RISCV_ASM_VDSO_DATA_H + +#include <linux/types.h> +#include <vdso/datapage.h> +#include <asm/hwprobe.h> + +struct arch_vdso_data { + /* Stash static answers to the hwprobe queries when all CPUs are selected. */ + __u64 all_cpu_hwprobe_values[RISCV_HWPROBE_MAX_KEY + 1]; + + /* Boolean indicating all CPUs have the same static hwprobe values. */ + __u8 homogeneous_cpus; +}; + +#endif /* __RISCV_ASM_VDSO_DATA_H */ diff --git a/arch/riscv/include/asm/vdso/gettimeofday.h b/arch/riscv/include/asm/vdso/gettimeofday.h index 77d9c2f721c4..ba3283cf7acc 100644 --- a/arch/riscv/include/asm/vdso/gettimeofday.h +++ b/arch/riscv/include/asm/vdso/gettimeofday.h @@ -9,6 +9,12 @@ #include <asm/csr.h> #include <uapi/linux/time.h> +/* + * 32-bit land is lacking generic time vsyscalls as well as the legacy 32-bit + * time syscalls like gettimeofday. Skip these definitions since on 32-bit. + */ +#ifdef CONFIG_GENERIC_TIME_VSYSCALL + #define VDSO_HAS_CLOCK_GETRES 1 static __always_inline @@ -60,6 +66,8 @@ int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts) return ret; } +#endif /* CONFIG_GENERIC_TIME_VSYSCALL */ + static __always_inline u64 __arch_get_hw_counter(s32 clock_mode, const struct vdso_data *vd) { diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h new file mode 100644 index 000000000000..8d745a4ad8a2 --- /dev/null +++ b/arch/riscv/include/uapi/asm/hwprobe.h @@ -0,0 +1,37 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Copyright 2023 Rivos, Inc + */ + +#ifndef _UAPI_ASM_HWPROBE_H +#define _UAPI_ASM_HWPROBE_H + +#include <linux/types.h> + +/* + * Interface for probing hardware capabilities from userspace, see + * Documentation/riscv/hwprobe.rst for more information. + */ +struct riscv_hwprobe { + __s64 key; + __u64 value; +}; + +#define RISCV_HWPROBE_KEY_MVENDORID 0 +#define RISCV_HWPROBE_KEY_MARCHID 1 +#define RISCV_HWPROBE_KEY_MIMPID 2 +#define RISCV_HWPROBE_KEY_BASE_BEHAVIOR 3 +#define RISCV_HWPROBE_BASE_BEHAVIOR_IMA (1 << 0) +#define RISCV_HWPROBE_KEY_IMA_EXT_0 4 +#define RISCV_HWPROBE_IMA_FD (1 << 0) +#define RISCV_HWPROBE_IMA_C (1 << 1) +#define RISCV_HWPROBE_KEY_CPUPERF_0 5 +#define RISCV_HWPROBE_MISALIGNED_UNKNOWN (0 << 0) +#define RISCV_HWPROBE_MISALIGNED_EMULATED (1 << 0) +#define RISCV_HWPROBE_MISALIGNED_SLOW (2 << 0) +#define RISCV_HWPROBE_MISALIGNED_FAST (3 << 0) +#define RISCV_HWPROBE_MISALIGNED_UNSUPPORTED (4 << 0) +#define RISCV_HWPROBE_MISALIGNED_MASK (7 << 0) +/* Increase RISCV_HWPROBE_MAX_KEY when adding items. */ + +#endif diff --git a/arch/riscv/include/uapi/asm/unistd.h b/arch/riscv/include/uapi/asm/unistd.h index 73d7cdd2ec49..950ab3fd4409 100644 --- a/arch/riscv/include/uapi/asm/unistd.h +++ b/arch/riscv/include/uapi/asm/unistd.h @@ -43,3 +43,12 @@ #define __NR_riscv_flush_icache (__NR_arch_specific_syscall + 15) #endif __SYSCALL(__NR_riscv_flush_icache, sys_riscv_flush_icache) + +/* + * Allows userspace to query the kernel for CPU architecture and + * microarchitecture details across a given set of CPUs. + */ +#ifndef __NR_riscv_hwprobe +#define __NR_riscv_hwprobe (__NR_arch_specific_syscall + 14) +#endif +__SYSCALL(__NR_riscv_hwprobe, sys_riscv_hwprobe) diff --git a/arch/riscv/kernel/alternative.c b/arch/riscv/kernel/alternative.c index 2354c69dc7d1..fc65c9293ac5 100644 --- a/arch/riscv/kernel/alternative.c +++ b/arch/riscv/kernel/alternative.c @@ -27,6 +27,8 @@ struct cpu_manufacturer_info_t { void (*patch_func)(struct alt_entry *begin, struct alt_entry *end, unsigned long archid, unsigned long impid, unsigned int stage); + void (*feature_probe_func)(unsigned int cpu, unsigned long archid, + unsigned long impid); }; static void __init_or_module riscv_fill_cpu_mfr_info(struct cpu_manufacturer_info_t *cpu_mfr_info) @@ -41,6 +43,7 @@ static void __init_or_module riscv_fill_cpu_mfr_info(struct cpu_manufacturer_inf cpu_mfr_info->imp_id = sbi_get_mimpid(); #endif + cpu_mfr_info->feature_probe_func = NULL; switch (cpu_mfr_info->vendor_id) { #ifdef CONFIG_ERRATA_SIFIVE case SIFIVE_VENDOR_ID: @@ -50,6 +53,7 @@ static void __init_or_module riscv_fill_cpu_mfr_info(struct cpu_manufacturer_inf #ifdef CONFIG_ERRATA_THEAD case THEAD_VENDOR_ID: cpu_mfr_info->patch_func = thead_errata_patch_func; + cpu_mfr_info->feature_probe_func = thead_feature_probe_func; break; #endif default: @@ -139,6 +143,20 @@ void riscv_alternative_fix_offsets(void *alt_ptr, unsigned int len, } } +/* Called on each CPU as it starts */ +void __init_or_module probe_vendor_features(unsigned int cpu) +{ + struct cpu_manufacturer_info_t cpu_mfr_info; + + riscv_fill_cpu_mfr_info(&cpu_mfr_info); + if (!cpu_mfr_info.feature_probe_func) + return; + + cpu_mfr_info.feature_probe_func(cpu, + cpu_mfr_info.arch_id, + cpu_mfr_info.imp_id); +} + /* * This is called very early in the boot process (directly after we run * a feature detect on the boot CPU). No need to worry about other CPUs @@ -193,6 +211,7 @@ void __init apply_boot_alternatives(void) /* If called on non-boot cpu things could go wrong */ WARN_ON(smp_processor_id() != 0); + probe_vendor_features(0); _apply_alternatives((struct alt_entry *)__alt_start, (struct alt_entry *)__alt_end, RISCV_ALTERNATIVES_BOOT); diff --git a/arch/riscv/kernel/compat_vdso/Makefile b/arch/riscv/kernel/compat_vdso/Makefile index 260daf3236d3..91a3431ae1fe 100644 --- a/arch/riscv/kernel/compat_vdso/Makefile +++ b/arch/riscv/kernel/compat_vdso/Makefile @@ -22,7 +22,7 @@ targets := $(obj-compat_vdso) compat_vdso.so compat_vdso.so.dbg compat_vdso.lds obj-compat_vdso := $(addprefix $(obj)/, $(obj-compat_vdso)) obj-y += compat_vdso.o -CPPFLAGS_compat_vdso.lds += -P -C -U$(ARCH) +CPPFLAGS_compat_vdso.lds += -P -C -DCOMPAT_VDSO -U$(ARCH) # Disable profiling and instrumentation for VDSO code GCOV_PROFILE := n diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c index 9203e18320f9..3df38052dcbd 100644 --- a/arch/riscv/kernel/cpu.c +++ b/arch/riscv/kernel/cpu.c @@ -7,6 +7,7 @@ #include <linux/init.h> #include <linux/seq_file.h> #include <linux/of.h> +#include <asm/cpufeature.h> #include <asm/csr.h> #include <asm/hwcap.h> #include <asm/sbi.h> @@ -70,12 +71,7 @@ int riscv_of_parent_hartid(struct device_node *node, unsigned long *hartid) return -1; } -struct riscv_cpuinfo { - unsigned long mvendorid; - unsigned long marchid; - unsigned long mimpid; -}; -static DEFINE_PER_CPU(struct riscv_cpuinfo, riscv_cpuinfo); +DEFINE_PER_CPU(struct riscv_cpuinfo, riscv_cpuinfo); unsigned long riscv_cached_mvendorid(unsigned int cpu_id) { diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index 00d7cd2c9043..52585e088873 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -25,6 +25,9 @@ unsigned long elf_hwcap __read_mostly; /* Host ISA bitmap */ static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly; +/* Performance information */ +DEFINE_PER_CPU(long, misaligned_access_speed); + /** * riscv_isa_extension_base() - Get base extension word * diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c index ddb2afba6d25..2867c12c3d16 100644 --- a/arch/riscv/kernel/smpboot.c +++ b/arch/riscv/kernel/smpboot.c @@ -168,6 +168,7 @@ asmlinkage __visible void smp_callin(void) notify_cpu_starting(curr_cpuid); numa_add_cpu(curr_cpuid); set_cpu_online(curr_cpuid, 1); + probe_vendor_features(curr_cpuid); /* * Remote TLB flushes are ignored while the CPU is offline, so emit diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c index 5d3f2fbeb33c..849b4170629d 100644 --- a/arch/riscv/kernel/sys_riscv.c +++ b/arch/riscv/kernel/sys_riscv.c @@ -6,9 +6,15 @@ */ #include <linux/syscalls.h> -#include <asm/unistd.h> #include <asm/cacheflush.h> +#include <asm/cpufeature.h> +#include <asm/hwprobe.h> +#include <asm/sbi.h> +#include <asm/switch_to.h> +#include <asm/uaccess.h> +#include <asm/unistd.h> #include <asm-generic/mman-common.h> +#include <vdso/vsyscall.h> static long riscv_sys_mmap(unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags, @@ -69,3 +75,223 @@ SYSCALL_DEFINE3(riscv_flush_icache, uintptr_t, start, uintptr_t, end, return 0; } + +/* + * The hwprobe interface, for allowing userspace to probe to see which features + * are supported by the hardware. See Documentation/riscv/hwprobe.rst for more + * details. + */ +static void hwprobe_arch_id(struct riscv_hwprobe *pair, + const struct cpumask *cpus) +{ + u64 id = -1ULL; + bool first = true; + int cpu; + + for_each_cpu(cpu, cpus) { + u64 cpu_id; + + switch (pair->key) { + case RISCV_HWPROBE_KEY_MVENDORID: + cpu_id = riscv_cached_mvendorid(cpu); + break; + case RISCV_HWPROBE_KEY_MIMPID: + cpu_id = riscv_cached_mimpid(cpu); + break; + case RISCV_HWPROBE_KEY_MARCHID: + cpu_id = riscv_cached_marchid(cpu); + break; + } + + if (first) + id = cpu_id; + + /* + * If there's a mismatch for the given set, return -1 in the + * value. + */ + if (id != cpu_id) { + id = -1ULL; + break; + } + } + + pair->value = id; +} + +static u64 hwprobe_misaligned(const struct cpumask *cpus) +{ + int cpu; + u64 perf = -1ULL; + + for_each_cpu(cpu, cpus) { + int this_perf = per_cpu(misaligned_access_speed, cpu); + + if (perf == -1ULL) + perf = this_perf; + + if (perf != this_perf) { + perf = RISCV_HWPROBE_MISALIGNED_UNKNOWN; + break; + } + } + + if (perf == -1ULL) + return RISCV_HWPROBE_MISALIGNED_UNKNOWN; + + return perf; +} + +static void hwprobe_one_pair(struct riscv_hwprobe *pair, + const struct cpumask *cpus) +{ + switch (pair->key) { + case RISCV_HWPROBE_KEY_MVENDORID: + case RISCV_HWPROBE_KEY_MARCHID: + case RISCV_HWPROBE_KEY_MIMPID: + hwprobe_arch_id(pair, cpus); + break; + /* + * The kernel already assumes that the base single-letter ISA + * extensions are supported on all harts, and only supports the + * IMA base, so just cheat a bit here and tell that to + * userspace. + */ + case RISCV_HWPROBE_KEY_BASE_BEHAVIOR: + pair->value = RISCV_HWPROBE_BASE_BEHAVIOR_IMA; + break; + + case RISCV_HWPROBE_KEY_IMA_EXT_0: + pair->value = 0; + if (has_fpu()) + pair->value |= RISCV_HWPROBE_IMA_FD; + + if (riscv_isa_extension_available(NULL, c)) + pair->value |= RISCV_HWPROBE_IMA_C; + + break; + + case RISCV_HWPROBE_KEY_CPUPERF_0: + pair->value = hwprobe_misaligned(cpus); + break; + + /* + * For forward compatibility, unknown keys don't fail the whole + * call, but get their element key set to -1 and value set to 0 + * indicating they're unrecognized. + */ + default: + pair->key = -1; + pair->value = 0; + break; + } +} + +static int do_riscv_hwprobe(struct riscv_hwprobe __user *pairs, + size_t pair_count, size_t cpu_count, + unsigned long __user *cpus_user, + unsigned int flags) +{ + size_t out; + int ret; + cpumask_t cpus; + + /* Check the reserved flags. */ + if (flags != 0) + return -EINVAL; + + /* + * The interface supports taking in a CPU mask, and returns values that + * are consistent across that mask. Allow userspace to specify NULL and + * 0 as a shortcut to all online CPUs. + */ + cpumask_clear(&cpus); + if (!cpu_count && !cpus_user) { + cpumask_copy(&cpus, cpu_online_mask); + } else { + if (cpu_count > cpumask_size()) + cpu_count = cpumask_size(); + + ret = copy_from_user(&cpus, cpus_user, cpu_count); + if (ret) + return -EFAULT; + + /* + * Userspace must provide at least one online CPU, without that + * there's no way to define what is supported. + */ + cpumask_and(&cpus, &cpus, cpu_online_mask); + if (cpumask_empty(&cpus)) + return -EINVAL; + } + + for (out = 0; out < pair_count; out++, pairs++) { + struct riscv_hwprobe pair; + + if (get_user(pair.key, &pairs->key)) + return -EFAULT; + + pair.value = 0; + hwprobe_one_pair(&pair, &cpus); + ret = put_user(pair.key, &pairs->key); + if (ret == 0) + ret = put_user(pair.value, &pairs->value); + + if (ret) + return -EFAULT; + } + + return 0; +} + +#ifdef CONFIG_MMU + +static int __init init_hwprobe_vdso_data(void) +{ + struct vdso_data *vd = __arch_get_k_vdso_data(); + struct arch_vdso_data *avd = &vd->arch_data; + u64 id_bitsmash = 0; + struct riscv_hwprobe pair; + int key; + + /* + * Initialize vDSO data with the answers for the "all CPUs" case, to + * save a syscall in the common case. + */ + for (key = 0; key <= RISCV_HWPROBE_MAX_KEY; key++) { + pair.key = key; + hwprobe_one_pair(&pair, cpu_online_mask); + + WARN_ON_ONCE(pair.key < 0); + + avd->all_cpu_hwprobe_values[key] = pair.value; + /* + * Smash together the vendor, arch, and impl IDs to see if + * they're all 0 or any negative. + */ + if (key <= RISCV_HWPROBE_KEY_MIMPID) + id_bitsmash |= pair.value; + } + + /* + * If the arch, vendor, and implementation ID are all the same across + * all harts, then assume all CPUs are the same, and allow the vDSO to + * answer queries for arbitrary masks. However if all values are 0 (not + * populated) or any value returns -1 (varies across CPUs), then the + * vDSO should defer to the kernel for exotic cpu masks. + */ + avd->homogeneous_cpus = (id_bitsmash > 0); + return 0; +} + +arch_initcall_sync(init_hwprobe_vdso_data); + +#endif /* CONFIG_MMU */ + +SYSCALL_DEFINE5(riscv_hwprobe, struct riscv_hwprobe __user *, pairs, + size_t, pair_count, size_t, cpu_count, unsigned long __user *, + cpus, unsigned int, flags) +{ + return do_riscv_hwprobe(pairs, pair_count, cpu_count, + cpus, flags); +} diff --git a/arch/riscv/kernel/vdso.c b/arch/riscv/kernel/vdso.c index cc2d1e8c8736..9a68e7eaae4d 100644 --- a/arch/riscv/kernel/vdso.c +++ b/arch/riscv/kernel/vdso.c @@ -14,13 +14,7 @@ #include <asm/page.h> #include <asm/vdso.h> #include <linux/time_namespace.h> - -#ifdef CONFIG_GENERIC_TIME_VSYSCALL #include <vdso/datapage.h> -#else -struct vdso_data { -}; -#endif enum vvar_pages { VVAR_DATA_PAGE_OFFSET, diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile index 06e6b27f3bcc..022258426050 100644 --- a/arch/riscv/kernel/vdso/Makefile +++ b/arch/riscv/kernel/vdso/Makefile @@ -12,6 +12,8 @@ vdso-syms += vgettimeofday endif vdso-syms += getcpu vdso-syms += flush_icache +vdso-syms += hwprobe +vdso-syms += sys_hwprobe # Files to link into the vdso obj-vdso = $(patsubst %, %.o, $(vdso-syms)) note.o @@ -23,6 +25,8 @@ ifneq ($(c-gettimeofday-y),) CFLAGS_vgettimeofday.o += -fPIC -include $(c-gettimeofday-y) endif +CFLAGS_hwprobe.o += -fPIC + # Build rules targets := $(obj-vdso) vdso.so vdso.so.dbg vdso.lds obj-vdso := $(addprefix $(obj)/, $(obj-vdso)) diff --git a/arch/riscv/kernel/vdso/hwprobe.c b/arch/riscv/kernel/vdso/hwprobe.c new file mode 100644 index 000000000000..d40bec6ac078 --- /dev/null +++ b/arch/riscv/kernel/vdso/hwprobe.c @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2023 Rivos, Inc + */ + +#include <linux/types.h> +#include <vdso/datapage.h> +#include <vdso/helpers.h> + +extern int riscv_hwprobe(struct riscv_hwprobe *pairs, size_t pair_count, + size_t cpu_count, unsigned long *cpus, + unsigned int flags); + +/* Add a prototype to avoid -Wmissing-prototypes warning. */ +int __vdso_riscv_hwprobe(struct riscv_hwprobe *pairs, size_t pair_count, + size_t cpu_count, unsigned long *cpus, + unsigned int flags); + +int __vdso_riscv_hwprobe(struct riscv_hwprobe *pairs, size_t pair_count, + size_t cpu_count, unsigned long *cpus, + unsigned int flags) +{ + const struct vdso_data *vd = __arch_get_vdso_data(); + const struct arch_vdso_data *avd = &vd->arch_data; + bool all_cpus = !cpu_count && !cpus; + struct riscv_hwprobe *p = pairs; + struct riscv_hwprobe *end = pairs + pair_count; + + /* + * Defer to the syscall for exotic requests. The vdso has answers + * stashed away only for the "all cpus" case. If all CPUs are + * homogeneous, then this function can handle requests for arbitrary + * masks. + */ + if ((flags != 0) || (!all_cpus && !avd->homogeneous_cpus)) + return riscv_hwprobe(pairs, pair_count, cpu_count, cpus, flags); + + /* This is something we can handle, fill out the pairs. */ + while (p < end) { + if (p->key <= RISCV_HWPROBE_MAX_KEY) { + p->value = avd->all_cpu_hwprobe_values[p->key]; + + } else { + p->key = -1; + p->value = 0; + } + + p++; + } + + return 0; +} diff --git a/arch/riscv/kernel/vdso/sys_hwprobe.S b/arch/riscv/kernel/vdso/sys_hwprobe.S new file mode 100644 index 000000000000..4e704146c77a --- /dev/null +++ b/arch/riscv/kernel/vdso/sys_hwprobe.S @@ -0,0 +1,15 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2023 Rivos, Inc */ + +#include <linux/linkage.h> +#include <asm/unistd.h> + +.text +ENTRY(riscv_hwprobe) + .cfi_startproc + li a7, __NR_riscv_hwprobe + ecall + ret + + .cfi_endproc +ENDPROC(riscv_hwprobe) diff --git a/arch/riscv/kernel/vdso/vdso.lds.S b/arch/riscv/kernel/vdso/vdso.lds.S index 4a0606633290..82ce64900f3d 100644 --- a/arch/riscv/kernel/vdso/vdso.lds.S +++ b/arch/riscv/kernel/vdso/vdso.lds.S @@ -82,6 +82,9 @@ VERSION #endif __vdso_getcpu; __vdso_flush_icache; +#ifndef COMPAT_VDSO + __vdso_riscv_hwprobe; +#endif local: *; }; } diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index 13a6837a0c6b..4bea26109450 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -63,6 +63,7 @@ TARGETS += pstore TARGETS += ptrace TARGETS += openat2 TARGETS += resctrl +TARGETS += riscv TARGETS += rlimits TARGETS += rseq TARGETS += rtc diff --git a/tools/testing/selftests/riscv/Makefile b/tools/testing/selftests/riscv/Makefile new file mode 100644 index 000000000000..32a72902d045 --- /dev/null +++ b/tools/testing/selftests/riscv/Makefile @@ -0,0 +1,58 @@ +# SPDX-License-Identifier: GPL-2.0 +# Originally tools/testing/arm64/Makefile + +# When ARCH not overridden for crosscompiling, lookup machine +ARCH ?= $(shell uname -m 2>/dev/null || echo not) + +ifneq (,$(filter $(ARCH),riscv)) +RISCV_SUBTARGETS ?= hwprobe +else +RISCV_SUBTARGETS := +endif + +CFLAGS := -Wall -O2 -g + +# A proper top_srcdir is needed by KSFT(lib.mk) +top_srcdir = $(realpath ../../../../) + +# Additional include paths needed by kselftest.h and local headers +CFLAGS += -I$(top_srcdir)/tools/testing/selftests/ + +CFLAGS += $(KHDR_INCLUDES) + +export CFLAGS +export top_srcdir + +all: + @for DIR in $(RISCV_SUBTARGETS); do \ + BUILD_TARGET=$(OUTPUT)/$$DIR; \ + mkdir -p $$BUILD_TARGET; \ + $(MAKE) OUTPUT=$$BUILD_TARGET -C $$DIR $@; \ + done + +install: all + @for DIR in $(RISCV_SUBTARGETS); do \ + BUILD_TARGET=$(OUTPUT)/$$DIR; \ + $(MAKE) OUTPUT=$$BUILD_TARGET -C $$DIR $@; \ + done + +run_tests: all + @for DIR in $(RISCV_SUBTARGETS); do \ + BUILD_TARGET=$(OUTPUT)/$$DIR; \ + $(MAKE) OUTPUT=$$BUILD_TARGET -C $$DIR $@; \ + done + +# Avoid any output on non riscv on emit_tests +emit_tests: all + @for DIR in $(RISCV_SUBTARGETS); do \ + BUILD_TARGET=$(OUTPUT)/$$DIR; \ + $(MAKE) OUTPUT=$$BUILD_TARGET -C $$DIR $@; \ + done + +clean: + @for DIR in $(RISCV_SUBTARGETS); do \ + BUILD_TARGET=$(OUTPUT)/$$DIR; \ + $(MAKE) OUTPUT=$$BUILD_TARGET -C $$DIR $@; \ + done + +.PHONY: all clean install run_tests emit_tests diff --git a/tools/testing/selftests/riscv/hwprobe/Makefile b/tools/testing/selftests/riscv/hwprobe/Makefile new file mode 100644 index 000000000000..ebdbb3c22e54 --- /dev/null +++ b/tools/testing/selftests/riscv/hwprobe/Makefile @@ -0,0 +1,10 @@ +# SPDX-License-Identifier: GPL-2.0 +# Copyright (C) 2021 ARM Limited +# Originally tools/testing/arm64/abi/Makefile + +TEST_GEN_PROGS := hwprobe + +include ../../lib.mk + +$(OUTPUT)/hwprobe: hwprobe.c sys_hwprobe.S + $(CC) -o$@ $(CFLAGS) $(LDFLAGS) $^ diff --git a/tools/testing/selftests/riscv/hwprobe/hwprobe.c b/tools/testing/selftests/riscv/hwprobe/hwprobe.c new file mode 100644 index 000000000000..09f290a67420 --- /dev/null +++ b/tools/testing/selftests/riscv/hwprobe/hwprobe.c @@ -0,0 +1,90 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <stddef.h> +#include <asm/hwprobe.h> + +/* + * Rather than relying on having a new enough libc to define this, just do it + * ourselves. This way we don't need to be coupled to a new-enough libc to + * contain the call. + */ +long riscv_hwprobe(struct riscv_hwprobe *pairs, size_t pair_count, + size_t cpu_count, unsigned long *cpus, unsigned int flags); + +int main(int argc, char **argv) +{ + struct riscv_hwprobe pairs[8]; + unsigned long cpus; + long out; + + /* Fake the CPU_SET ops. */ + cpus = -1; + + /* + * Just run a basic test: pass enough pairs to get up to the base + * behavior, and then check to make sure it's sane. + */ + for (long i = 0; i < 8; i++) + pairs[i].key = i; + out = riscv_hwprobe(pairs, 8, 1, &cpus, 0); + if (out != 0) + return -1; + for (long i = 0; i < 4; ++i) { + /* Fail if the kernel claims not to recognize a base key. */ + if ((i < 4) && (pairs[i].key != i)) + return -2; + + if (pairs[i].key != RISCV_HWPROBE_KEY_BASE_BEHAVIOR) + continue; + + if (pairs[i].value & RISCV_HWPROBE_BASE_BEHAVIOR_IMA) + continue; + + return -3; + } + + /* + * This should also work with a NULL CPU set, but should not work + * with an improperly supplied CPU set. + */ + out = riscv_hwprobe(pairs, 8, 0, 0, 0); + if (out != 0) + return -4; + + out = riscv_hwprobe(pairs, 8, 0, &cpus, 0); + if (out == 0) + return -5; + + out = riscv_hwprobe(pairs, 8, 1, 0, 0); + if (out == 0) + return -6; + + /* + * Check that keys work by providing one that we know exists, and + * checking to make sure the resultig pair is what we asked for. + */ + pairs[0].key = RISCV_HWPROBE_KEY_BASE_BEHAVIOR; + out = riscv_hwprobe(pairs, 1, 1, &cpus, 0); + if (out != 0) + return -7; + if (pairs[0].key != RISCV_HWPROBE_KEY_BASE_BEHAVIOR) + return -8; + + /* + * Check that an unknown key gets overwritten with -1, + * but doesn't block elements after it. + */ + pairs[0].key = 0x5555; + pairs[1].key = 1; + pairs[1].value = 0xAAAA; + out = riscv_hwprobe(pairs, 2, 0, 0, 0); + if (out != 0) + return -9; + + if (pairs[0].key != -1) + return -10; + + if ((pairs[1].key != 1) || (pairs[1].value == 0xAAAA)) + return -11; + + return 0; +} diff --git a/tools/testing/selftests/riscv/hwprobe/sys_hwprobe.S b/tools/testing/selftests/riscv/hwprobe/sys_hwprobe.S new file mode 100644 index 000000000000..a4773c88d267 --- /dev/null +++ b/tools/testing/selftests/riscv/hwprobe/sys_hwprobe.S @@ -0,0 +1,12 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2023 Rivos, Inc */ + +.text +.global riscv_hwprobe +riscv_hwprobe: + # Put __NR_riscv_hwprobe in the syscall number register, then just shim + # back the kernel's return. This doesn't do any sort of errno + # handling, the caller can deal with it. + li a7, 258 + ecall + ret |