xref: /openbmc/linux/arch/riscv/kernel/cpu.c (revision 9853f130)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2012 Regents of the University of California
4  */
5 
6 #include <linux/acpi.h>
7 #include <linux/cpu.h>
8 #include <linux/ctype.h>
9 #include <linux/init.h>
10 #include <linux/seq_file.h>
11 #include <linux/of.h>
12 #include <asm/acpi.h>
13 #include <asm/cpufeature.h>
14 #include <asm/csr.h>
15 #include <asm/hwcap.h>
16 #include <asm/sbi.h>
17 #include <asm/smp.h>
18 #include <asm/pgtable.h>
19 
20 bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
21 {
22 	return phys_id == cpuid_to_hartid_map(cpu);
23 }
24 
25 /*
26  * Returns the hart ID of the given device tree node, or -ENODEV if the node
27  * isn't an enabled and valid RISC-V hart node.
28  */
29 int riscv_of_processor_hartid(struct device_node *node, unsigned long *hart)
30 {
31 	int cpu;
32 
33 	*hart = (unsigned long)of_get_cpu_hwid(node, 0);
34 	if (*hart == ~0UL) {
35 		pr_warn("Found CPU without hart ID\n");
36 		return -ENODEV;
37 	}
38 
39 	cpu = riscv_hartid_to_cpuid(*hart);
40 	if (cpu < 0)
41 		return cpu;
42 
43 	if (!cpu_possible(cpu))
44 		return -ENODEV;
45 
46 	return 0;
47 }
48 
49 int __init riscv_early_of_processor_hartid(struct device_node *node, unsigned long *hart)
50 {
51 	const char *isa;
52 
53 	if (!of_device_is_compatible(node, "riscv")) {
54 		pr_warn("Found incompatible CPU\n");
55 		return -ENODEV;
56 	}
57 
58 	*hart = (unsigned long)of_get_cpu_hwid(node, 0);
59 	if (*hart == ~0UL) {
60 		pr_warn("Found CPU without hart ID\n");
61 		return -ENODEV;
62 	}
63 
64 	if (!of_device_is_available(node)) {
65 		pr_info("CPU with hartid=%lu is not available\n", *hart);
66 		return -ENODEV;
67 	}
68 
69 	if (of_property_read_string(node, "riscv,isa-base", &isa))
70 		goto old_interface;
71 
72 	if (IS_ENABLED(CONFIG_32BIT) && strncasecmp(isa, "rv32i", 5)) {
73 		pr_warn("CPU with hartid=%lu does not support rv32i", *hart);
74 		return -ENODEV;
75 	}
76 
77 	if (IS_ENABLED(CONFIG_64BIT) && strncasecmp(isa, "rv64i", 5)) {
78 		pr_warn("CPU with hartid=%lu does not support rv64i", *hart);
79 		return -ENODEV;
80 	}
81 
82 	if (!of_property_present(node, "riscv,isa-extensions"))
83 		return -ENODEV;
84 
85 	if (of_property_match_string(node, "riscv,isa-extensions", "i") < 0 ||
86 	    of_property_match_string(node, "riscv,isa-extensions", "m") < 0 ||
87 	    of_property_match_string(node, "riscv,isa-extensions", "a") < 0) {
88 		pr_warn("CPU with hartid=%lu does not support ima", *hart);
89 		return -ENODEV;
90 	}
91 
92 	return 0;
93 
94 old_interface:
95 	if (!riscv_isa_fallback) {
96 		pr_warn("CPU with hartid=%lu is invalid: this kernel does not parse \"riscv,isa\"",
97 			*hart);
98 		return -ENODEV;
99 	}
100 
101 	if (of_property_read_string(node, "riscv,isa", &isa)) {
102 		pr_warn("CPU with hartid=%lu has no \"riscv,isa-base\" or \"riscv,isa\" property\n",
103 			*hart);
104 		return -ENODEV;
105 	}
106 
107 	if (IS_ENABLED(CONFIG_32BIT) && strncasecmp(isa, "rv32ima", 7)) {
108 		pr_warn("CPU with hartid=%lu does not support rv32ima", *hart);
109 		return -ENODEV;
110 	}
111 
112 	if (IS_ENABLED(CONFIG_64BIT) && strncasecmp(isa, "rv64ima", 7)) {
113 		pr_warn("CPU with hartid=%lu does not support rv64ima", *hart);
114 		return -ENODEV;
115 	}
116 
117 	return 0;
118 }
119 
120 /*
121  * Find hart ID of the CPU DT node under which given DT node falls.
122  *
123  * To achieve this, we walk up the DT tree until we find an active
124  * RISC-V core (HART) node and extract the cpuid from it.
125  */
126 int riscv_of_parent_hartid(struct device_node *node, unsigned long *hartid)
127 {
128 	for (; node; node = node->parent) {
129 		if (of_device_is_compatible(node, "riscv")) {
130 			*hartid = (unsigned long)of_get_cpu_hwid(node, 0);
131 			if (*hartid == ~0UL) {
132 				pr_warn("Found CPU without hart ID\n");
133 				return -ENODEV;
134 			}
135 			return 0;
136 		}
137 	}
138 
139 	return -1;
140 }
141 
142 DEFINE_PER_CPU(struct riscv_cpuinfo, riscv_cpuinfo);
143 
144 unsigned long riscv_cached_mvendorid(unsigned int cpu_id)
145 {
146 	struct riscv_cpuinfo *ci = per_cpu_ptr(&riscv_cpuinfo, cpu_id);
147 
148 	return ci->mvendorid;
149 }
150 EXPORT_SYMBOL(riscv_cached_mvendorid);
151 
152 unsigned long riscv_cached_marchid(unsigned int cpu_id)
153 {
154 	struct riscv_cpuinfo *ci = per_cpu_ptr(&riscv_cpuinfo, cpu_id);
155 
156 	return ci->marchid;
157 }
158 EXPORT_SYMBOL(riscv_cached_marchid);
159 
160 unsigned long riscv_cached_mimpid(unsigned int cpu_id)
161 {
162 	struct riscv_cpuinfo *ci = per_cpu_ptr(&riscv_cpuinfo, cpu_id);
163 
164 	return ci->mimpid;
165 }
166 EXPORT_SYMBOL(riscv_cached_mimpid);
167 
168 static int riscv_cpuinfo_starting(unsigned int cpu)
169 {
170 	struct riscv_cpuinfo *ci = this_cpu_ptr(&riscv_cpuinfo);
171 
172 #if IS_ENABLED(CONFIG_RISCV_SBI)
173 	ci->mvendorid = sbi_spec_is_0_1() ? 0 : sbi_get_mvendorid();
174 	ci->marchid = sbi_spec_is_0_1() ? 0 : sbi_get_marchid();
175 	ci->mimpid = sbi_spec_is_0_1() ? 0 : sbi_get_mimpid();
176 #elif IS_ENABLED(CONFIG_RISCV_M_MODE)
177 	ci->mvendorid = csr_read(CSR_MVENDORID);
178 	ci->marchid = csr_read(CSR_MARCHID);
179 	ci->mimpid = csr_read(CSR_MIMPID);
180 #else
181 	ci->mvendorid = 0;
182 	ci->marchid = 0;
183 	ci->mimpid = 0;
184 #endif
185 
186 	return 0;
187 }
188 
189 static int __init riscv_cpuinfo_init(void)
190 {
191 	int ret;
192 
193 	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "riscv/cpuinfo:starting",
194 				riscv_cpuinfo_starting, NULL);
195 	if (ret < 0) {
196 		pr_err("cpuinfo: failed to register hotplug callbacks.\n");
197 		return ret;
198 	}
199 
200 	return 0;
201 }
202 arch_initcall(riscv_cpuinfo_init);
203 
204 #ifdef CONFIG_PROC_FS
205 
206 static void print_isa(struct seq_file *f)
207 {
208 	seq_puts(f, "isa\t\t: ");
209 
210 	if (IS_ENABLED(CONFIG_32BIT))
211 		seq_write(f, "rv32", 4);
212 	else
213 		seq_write(f, "rv64", 4);
214 
215 	for (int i = 0; i < riscv_isa_ext_count; i++) {
216 		if (!__riscv_isa_extension_available(NULL, riscv_isa_ext[i].id))
217 			continue;
218 
219 		/* Only multi-letter extensions are split by underscores */
220 		if (strnlen(riscv_isa_ext[i].name, 2) != 1)
221 			seq_puts(f, "_");
222 
223 		seq_printf(f, "%s", riscv_isa_ext[i].name);
224 	}
225 
226 	seq_puts(f, "\n");
227 }
228 
229 static void print_mmu(struct seq_file *f)
230 {
231 	const char *sv_type;
232 
233 #ifdef CONFIG_MMU
234 #if defined(CONFIG_32BIT)
235 	sv_type = "sv32";
236 #elif defined(CONFIG_64BIT)
237 	if (pgtable_l5_enabled)
238 		sv_type = "sv57";
239 	else if (pgtable_l4_enabled)
240 		sv_type = "sv48";
241 	else
242 		sv_type = "sv39";
243 #endif
244 #else
245 	sv_type = "none";
246 #endif /* CONFIG_MMU */
247 	seq_printf(f, "mmu\t\t: %s\n", sv_type);
248 }
249 
250 static void *c_start(struct seq_file *m, loff_t *pos)
251 {
252 	if (*pos == nr_cpu_ids)
253 		return NULL;
254 
255 	*pos = cpumask_next(*pos - 1, cpu_online_mask);
256 	if ((*pos) < nr_cpu_ids)
257 		return (void *)(uintptr_t)(1 + *pos);
258 	return NULL;
259 }
260 
261 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
262 {
263 	(*pos)++;
264 	return c_start(m, pos);
265 }
266 
267 static void c_stop(struct seq_file *m, void *v)
268 {
269 }
270 
271 static int c_show(struct seq_file *m, void *v)
272 {
273 	unsigned long cpu_id = (unsigned long)v - 1;
274 	struct riscv_cpuinfo *ci = per_cpu_ptr(&riscv_cpuinfo, cpu_id);
275 	struct device_node *node;
276 	const char *compat;
277 
278 	seq_printf(m, "processor\t: %lu\n", cpu_id);
279 	seq_printf(m, "hart\t\t: %lu\n", cpuid_to_hartid_map(cpu_id));
280 	print_isa(m);
281 	print_mmu(m);
282 
283 	if (acpi_disabled) {
284 		node = of_get_cpu_node(cpu_id, NULL);
285 
286 		if (!of_property_read_string(node, "compatible", &compat) &&
287 		    strcmp(compat, "riscv"))
288 			seq_printf(m, "uarch\t\t: %s\n", compat);
289 
290 		of_node_put(node);
291 	}
292 
293 	seq_printf(m, "mvendorid\t: 0x%lx\n", ci->mvendorid);
294 	seq_printf(m, "marchid\t\t: 0x%lx\n", ci->marchid);
295 	seq_printf(m, "mimpid\t\t: 0x%lx\n", ci->mimpid);
296 	seq_puts(m, "\n");
297 
298 	return 0;
299 }
300 
301 const struct seq_operations cpuinfo_op = {
302 	.start	= c_start,
303 	.next	= c_next,
304 	.stop	= c_stop,
305 	.show	= c_show
306 };
307 
308 #endif /* CONFIG_PROC_FS */
309