linux/arch/riscv/kernel/cpu.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012 Regents of the University of California
 */

#include <linux/acpi.h>
#include <linux/cpu.h>
#include <linux/ctype.h>
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/of.h>
#include <asm/acpi.h>
#include <asm/cpufeature.h>
#include <asm/csr.h>
#include <asm/hwcap.h>
#include <asm/sbi.h>
#include <asm/smp.h>
#include <asm/pgtable.h>

/*
 * Returns the hart ID of the given device tree node, or -ENODEV if the node
 * isn't an enabled and valid RISC-V hart node.
 */
int riscv_of_processor_hartid(struct device_node *node, unsigned long *hart)
{
	int cpu;

	*hart = (unsigned long)of_get_cpu_hwid(node, 0);
	if (*hart == ~0UL) {
		pr_warn("Found CPU without hart ID\n");
		return -ENODEV;
	}

	cpu = riscv_hartid_to_cpuid(*hart);
	if (cpu < 0)
		return cpu;

	if (!cpu_possible(cpu))
		return -ENODEV;

	return 0;
}

int riscv_early_of_processor_hartid(struct device_node *node, unsigned long *hart)
{
	const char *isa;

	if (!of_device_is_compatible(node, "riscv")) {
		pr_warn("Found incompatible CPU\n");
		return -ENODEV;
	}

	*hart = (unsigned long)of_get_cpu_hwid(node, 0);
	if (*hart == ~0UL) {
		pr_warn("Found CPU without hart ID\n");
		return -ENODEV;
	}

	if (!of_device_is_available(node)) {
		pr_info("CPU with hartid=%lu is not available\n", *hart);
		return -ENODEV;
	}

	if (of_property_read_string(node, "riscv,isa", &isa)) {
		pr_warn("CPU with hartid=%lu has no \"riscv,isa\" property\n", *hart);
		return -ENODEV;
	}

	if (IS_ENABLED(CONFIG_32BIT) && strncasecmp(isa, "rv32ima", 7)) {
		pr_warn("CPU with hartid=%lu does not support rv32ima", *hart);
		return -ENODEV;
	}

	if (IS_ENABLED(CONFIG_64BIT) && strncasecmp(isa, "rv64ima", 7)) {
		pr_warn("CPU with hartid=%lu does not support rv64ima", *hart);
		return -ENODEV;
	}

	return 0;
}

/*
 * Find hart ID of the CPU DT node under which given DT node falls.
 *
 * To achieve this, we walk up the DT tree until we find an active
 * RISC-V core (HART) node and extract the cpuid from it.
 */
int riscv_of_parent_hartid(struct device_node *node, unsigned long *hartid)
{
	int rc;

	for (; node; node = node->parent) {
		if (of_device_is_compatible(node, "riscv")) {
			rc = riscv_of_processor_hartid(node, hartid);
			if (!rc)
				return 0;
		}
	}

	return -1;
}

DEFINE_PER_CPU(struct riscv_cpuinfo, riscv_cpuinfo);

unsigned long riscv_cached_mvendorid(unsigned int cpu_id)
{
	struct riscv_cpuinfo *ci = per_cpu_ptr(&riscv_cpuinfo, cpu_id);

	return ci->mvendorid;
}
EXPORT_SYMBOL(riscv_cached_mvendorid);

unsigned long riscv_cached_marchid(unsigned int cpu_id)
{
	struct riscv_cpuinfo *ci = per_cpu_ptr(&riscv_cpuinfo, cpu_id);

	return ci->marchid;
}
EXPORT_SYMBOL(riscv_cached_marchid);

unsigned long riscv_cached_mimpid(unsigned int cpu_id)
{
	struct riscv_cpuinfo *ci = per_cpu_ptr(&riscv_cpuinfo, cpu_id);

	return ci->mimpid;
}
EXPORT_SYMBOL(riscv_cached_mimpid);

static int riscv_cpuinfo_starting(unsigned int cpu)
{
	struct riscv_cpuinfo *ci = this_cpu_ptr(&riscv_cpuinfo);

#if IS_ENABLED(CONFIG_RISCV_SBI)
	ci->mvendorid = sbi_spec_is_0_1() ? 0 : sbi_get_mvendorid();
	ci->marchid = sbi_spec_is_0_1() ? 0 : sbi_get_marchid();
	ci->mimpid = sbi_spec_is_0_1() ? 0 : sbi_get_mimpid();
#elif IS_ENABLED(CONFIG_RISCV_M_MODE)
	ci->mvendorid = csr_read(CSR_MVENDORID);
	ci->marchid = csr_read(CSR_MARCHID);
	ci->mimpid = csr_read(CSR_MIMPID);
#else
	ci->mvendorid = 0;
	ci->marchid = 0;
	ci->mimpid = 0;
#endif

	return 0;
}

static int __init riscv_cpuinfo_init(void)
{
	int ret;

	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "riscv/cpuinfo:starting",
				riscv_cpuinfo_starting, NULL);
	if (ret < 0) {
		pr_err("cpuinfo: failed to register hotplug callbacks.\n");
		return ret;
	}

	return 0;
}
arch_initcall(riscv_cpuinfo_init);

#ifdef CONFIG_PROC_FS

static void print_isa_ext(struct seq_file *f)
{
	for (int i = 0; i < riscv_isa_ext_count; i++) {
		const struct riscv_isa_ext_data *edata = &riscv_isa_ext[i];
		if (!__riscv_isa_extension_available(NULL, edata->isa_ext_id))
			continue;
		seq_printf(f, "_%s", edata->uprop);
	}
}

/*
 * These are the only valid base (single letter) ISA extensions as per the spec.
 * It also specifies the canonical order in which it appears in the spec.
 * Some of the extension may just be a place holder for now (B, K, P, J).
 * This should be updated once corresponding extensions are ratified.
 */
static const char base_riscv_exts[13] = "imafdqcbkjpvh";

static void print_isa(struct seq_file *f)
{
	int i;

	seq_puts(f, "isa\t\t: ");
	if (IS_ENABLED(CONFIG_32BIT))
		seq_write(f, "rv32", 4);
	else
		seq_write(f, "rv64", 4);

	for (i = 0; i < sizeof(base_riscv_exts); i++) {
		if (__riscv_isa_extension_available(NULL, base_riscv_exts[i] - 'a'))
			/* Print only enabled the base ISA extensions */
			seq_write(f, &base_riscv_exts[i], 1);
	}
	print_isa_ext(f);
	seq_puts(f, "\n");
}

static void print_mmu(struct seq_file *f)
{
	char sv_type[16];

#ifdef CONFIG_MMU
#if defined(CONFIG_32BIT)
	strncpy(sv_type, "sv32", 5);
#elif defined(CONFIG_64BIT)
	if (pgtable_l5_enabled)
		strncpy(sv_type, "sv57", 5);
	else if (pgtable_l4_enabled)
		strncpy(sv_type, "sv48", 5);
	else
		strncpy(sv_type, "sv39", 5);
#endif
#else
	strncpy(sv_type, "none", 5);
#endif /* CONFIG_MMU */
	seq_printf(f, "mmu\t\t: %s\n", sv_type);
}

static void *c_start(struct seq_file *m, loff_t *pos)
{
	if (*pos == nr_cpu_ids)
		return NULL;

	*pos = cpumask_next(*pos - 1, cpu_online_mask);
	if ((*pos) < nr_cpu_ids)
		return (void *)(uintptr_t)(1 + *pos);
	return NULL;
}

static void *c_next(struct seq_file *m, void *v, loff_t *pos)
{
	(*pos)++;
	return c_start(m, pos);
}

static void c_stop(struct seq_file *m, void *v)
{
}

static int c_show(struct seq_file *m, void *v)
{
	unsigned long cpu_id = (unsigned long)v - 1;
	struct riscv_cpuinfo *ci = per_cpu_ptr(&riscv_cpuinfo, cpu_id);
	struct device_node *node;
	const char *compat;

	seq_printf(m, "processor\t: %lu\n", cpu_id);
	seq_printf(m, "hart\t\t: %lu\n", cpuid_to_hartid_map(cpu_id));
	print_isa(m);
	print_mmu(m);

	if (acpi_disabled) {
		node = of_get_cpu_node(cpu_id, NULL);

		if (!of_property_read_string(node, "compatible", &compat) &&
		    strcmp(compat, "riscv"))
			seq_printf(m, "uarch\t\t: %s\n", compat);

		of_node_put(node);
	}

	seq_printf(m, "mvendorid\t: 0x%lx\n", ci->mvendorid);
	seq_printf(m, "marchid\t\t: 0x%lx\n", ci->marchid);
	seq_printf(m, "mimpid\t\t: 0x%lx\n", ci->mimpid);
	seq_puts(m, "\n");

	return 0;
}

const struct seq_operations cpuinfo_op = {
	.start	= c_start,
	.next	= c_next,
	.stop	= c_stop,
	.show	= c_show
};

#endif /* CONFIG_PROC_FS */