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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-18 18:50:36 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-18 18:50:36 +0000 |
commit | 50ba0232fd5312410f1b65247e774244f89a628e (patch) | |
tree | fd8f2fc78e9e548af0ff9590276602ee6125be00 /arch/riscv/kernel/sys_hwprobe.c | |
parent | Releasing progress-linux version 6.7.12-1~progress7.99u1. (diff) | |
download | linux-50ba0232fd5312410f1b65247e774244f89a628e.tar.xz linux-50ba0232fd5312410f1b65247e774244f89a628e.zip |
Merging upstream version 6.8.9.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/riscv/kernel/sys_hwprobe.c')
-rw-r--r-- | arch/riscv/kernel/sys_hwprobe.c | 411 |
1 files changed, 411 insertions, 0 deletions
diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c new file mode 100644 index 0000000000..a7c56b41ef --- /dev/null +++ b/arch/riscv/kernel/sys_hwprobe.c @@ -0,0 +1,411 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * The hwprobe interface, for allowing userspace to probe to see which features + * are supported by the hardware. See Documentation/arch/riscv/hwprobe.rst for + * more details. + */ +#include <linux/syscalls.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/vector.h> +#include <vdso/vsyscall.h> + + +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; + first = false; + } + + /* + * 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 void hwprobe_isa_ext0(struct riscv_hwprobe *pair, + const struct cpumask *cpus) +{ + int cpu; + u64 missing = 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; + + if (has_vector()) + pair->value |= RISCV_HWPROBE_IMA_V; + + /* + * Loop through and record extensions that 1) anyone has, and 2) anyone + * doesn't have. + */ + for_each_cpu(cpu, cpus) { + struct riscv_isainfo *isainfo = &hart_isa[cpu]; + +#define EXT_KEY(ext) \ + do { \ + if (__riscv_isa_extension_available(isainfo->isa, RISCV_ISA_EXT_##ext)) \ + pair->value |= RISCV_HWPROBE_EXT_##ext; \ + else \ + missing |= RISCV_HWPROBE_EXT_##ext; \ + } while (false) + + /* + * Only use EXT_KEY() for extensions which can be exposed to userspace, + * regardless of the kernel's configuration, as no other checks, besides + * presence in the hart_isa bitmap, are made. + */ + EXT_KEY(ZBA); + EXT_KEY(ZBB); + EXT_KEY(ZBS); + EXT_KEY(ZICBOZ); + EXT_KEY(ZBC); + + EXT_KEY(ZBKB); + EXT_KEY(ZBKC); + EXT_KEY(ZBKX); + EXT_KEY(ZKND); + EXT_KEY(ZKNE); + EXT_KEY(ZKNH); + EXT_KEY(ZKSED); + EXT_KEY(ZKSH); + EXT_KEY(ZKT); + EXT_KEY(ZIHINTNTL); + EXT_KEY(ZTSO); + EXT_KEY(ZACAS); + EXT_KEY(ZICOND); + + if (has_vector()) { + EXT_KEY(ZVBB); + EXT_KEY(ZVBC); + EXT_KEY(ZVKB); + EXT_KEY(ZVKG); + EXT_KEY(ZVKNED); + EXT_KEY(ZVKNHA); + EXT_KEY(ZVKNHB); + EXT_KEY(ZVKSED); + EXT_KEY(ZVKSH); + EXT_KEY(ZVKT); + EXT_KEY(ZVFH); + EXT_KEY(ZVFHMIN); + } + + if (has_fpu()) { + EXT_KEY(ZFH); + EXT_KEY(ZFHMIN); + EXT_KEY(ZFA); + } +#undef EXT_KEY + } + + /* Now turn off reporting features if any CPU is missing it. */ + pair->value &= ~missing; +} + +static bool hwprobe_ext0_has(const struct cpumask *cpus, unsigned long ext) +{ + struct riscv_hwprobe pair; + + hwprobe_isa_ext0(&pair, cpus); + return (pair.value & ext); +} + +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: + hwprobe_isa_ext0(pair, cpus); + break; + + case RISCV_HWPROBE_KEY_CPUPERF_0: + pair->value = hwprobe_misaligned(cpus); + break; + + case RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE: + pair->value = 0; + if (hwprobe_ext0_has(cpus, RISCV_HWPROBE_EXT_ZICBOZ)) + pair->value = riscv_cboz_block_size; + 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 hwprobe_get_values(struct riscv_hwprobe __user *pairs, + size_t pair_count, size_t cpusetsize, + 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 (!cpusetsize && !cpus_user) { + cpumask_copy(&cpus, cpu_online_mask); + } else { + if (cpusetsize > cpumask_size()) + cpusetsize = cpumask_size(); + + ret = copy_from_user(&cpus, cpus_user, cpusetsize); + 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; +} + +static int hwprobe_get_cpus(struct riscv_hwprobe __user *pairs, + size_t pair_count, size_t cpusetsize, + unsigned long __user *cpus_user, + unsigned int flags) +{ + cpumask_t cpus, one_cpu; + bool clear_all = false; + size_t i; + int ret; + + if (flags != RISCV_HWPROBE_WHICH_CPUS) + return -EINVAL; + + if (!cpusetsize || !cpus_user) + return -EINVAL; + + if (cpusetsize > cpumask_size()) + cpusetsize = cpumask_size(); + + ret = copy_from_user(&cpus, cpus_user, cpusetsize); + if (ret) + return -EFAULT; + + if (cpumask_empty(&cpus)) + cpumask_copy(&cpus, cpu_online_mask); + + cpumask_and(&cpus, &cpus, cpu_online_mask); + + cpumask_clear(&one_cpu); + + for (i = 0; i < pair_count; i++) { + struct riscv_hwprobe pair, tmp; + int cpu; + + ret = copy_from_user(&pair, &pairs[i], sizeof(pair)); + if (ret) + return -EFAULT; + + if (!riscv_hwprobe_key_is_valid(pair.key)) { + clear_all = true; + pair = (struct riscv_hwprobe){ .key = -1, }; + ret = copy_to_user(&pairs[i], &pair, sizeof(pair)); + if (ret) + return -EFAULT; + } + + if (clear_all) + continue; + + tmp = (struct riscv_hwprobe){ .key = pair.key, }; + + for_each_cpu(cpu, &cpus) { + cpumask_set_cpu(cpu, &one_cpu); + + hwprobe_one_pair(&tmp, &one_cpu); + + if (!riscv_hwprobe_pair_cmp(&tmp, &pair)) + cpumask_clear_cpu(cpu, &cpus); + + cpumask_clear_cpu(cpu, &one_cpu); + } + } + + if (clear_all) + cpumask_clear(&cpus); + + ret = copy_to_user(cpus_user, &cpus, cpusetsize); + if (ret) + return -EFAULT; + + return 0; +} + +static int do_riscv_hwprobe(struct riscv_hwprobe __user *pairs, + size_t pair_count, size_t cpusetsize, + unsigned long __user *cpus_user, + unsigned int flags) +{ + if (flags & RISCV_HWPROBE_WHICH_CPUS) + return hwprobe_get_cpus(pairs, pair_count, cpusetsize, + cpus_user, flags); + + return hwprobe_get_values(pairs, pair_count, cpusetsize, + cpus_user, flags); +} + +#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 && id_bitsmash != -1; + 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, cpusetsize, unsigned long __user *, + cpus, unsigned int, flags) +{ + return do_riscv_hwprobe(pairs, pair_count, cpusetsize, + cpus, flags); +} |