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1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  Copyright IBM Corp. 2008
4  *  Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
5  */
6 
7 #define KMSG_COMPONENT "cpu"
8 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
9 
10 #include <linux/stop_machine.h>
11 #include <linux/cpufeature.h>
12 #include <linux/bitops.h>
13 #include <linux/kernel.h>
14 #include <linux/sched/mm.h>
15 #include <linux/init.h>
16 #include <linux/seq_file.h>
17 #include <linux/mm_types.h>
18 #include <linux/delay.h>
19 #include <linux/cpu.h>
20 
21 #include <asm/diag.h>
22 #include <asm/facility.h>
23 #include <asm/elf.h>
24 #include <asm/lowcore.h>
25 #include <asm/param.h>
26 #include <asm/smp.h>
27 
28 struct cpu_info {
29 	unsigned int cpu_mhz_dynamic;
30 	unsigned int cpu_mhz_static;
31 	struct cpuid cpu_id;
32 };
33 
34 static DEFINE_PER_CPU(struct cpu_info, cpu_info);
35 static DEFINE_PER_CPU(int, cpu_relax_retry);
36 
37 static bool machine_has_cpu_mhz;
38 
cpu_detect_mhz_feature(void)39 void __init cpu_detect_mhz_feature(void)
40 {
41 	if (test_facility(34) && __ecag(ECAG_CPU_ATTRIBUTE, 0) != -1UL)
42 		machine_has_cpu_mhz = true;
43 }
44 
update_cpu_mhz(void * arg)45 static void update_cpu_mhz(void *arg)
46 {
47 	unsigned long mhz;
48 	struct cpu_info *c;
49 
50 	mhz = __ecag(ECAG_CPU_ATTRIBUTE, 0);
51 	c = this_cpu_ptr(&cpu_info);
52 	c->cpu_mhz_dynamic = mhz >> 32;
53 	c->cpu_mhz_static = mhz & 0xffffffff;
54 }
55 
s390_update_cpu_mhz(void)56 void s390_update_cpu_mhz(void)
57 {
58 	s390_adjust_jiffies();
59 	if (machine_has_cpu_mhz)
60 		on_each_cpu(update_cpu_mhz, NULL, 0);
61 }
62 
stop_machine_yield(const struct cpumask * cpumask)63 void notrace stop_machine_yield(const struct cpumask *cpumask)
64 {
65 	int cpu, this_cpu;
66 
67 	this_cpu = smp_processor_id();
68 	if (__this_cpu_inc_return(cpu_relax_retry) >= spin_retry) {
69 		__this_cpu_write(cpu_relax_retry, 0);
70 		cpu = cpumask_next_wrap(this_cpu, cpumask, this_cpu, false);
71 		if (cpu >= nr_cpu_ids)
72 			return;
73 		if (arch_vcpu_is_preempted(cpu))
74 			smp_yield_cpu(cpu);
75 	}
76 }
77 
78 /*
79  * cpu_init - initializes state that is per-CPU.
80  */
cpu_init(void)81 void cpu_init(void)
82 {
83 	struct cpuid *id = this_cpu_ptr(&cpu_info.cpu_id);
84 
85 	get_cpu_id(id);
86 	if (machine_has_cpu_mhz)
87 		update_cpu_mhz(NULL);
88 	mmgrab(&init_mm);
89 	current->active_mm = &init_mm;
90 	BUG_ON(current->mm);
91 	enter_lazy_tlb(&init_mm, current);
92 }
93 
94 /*
95  * cpu_have_feature - Test CPU features on module initialization
96  */
cpu_have_feature(unsigned int num)97 int cpu_have_feature(unsigned int num)
98 {
99 	return elf_hwcap & (1UL << num);
100 }
101 EXPORT_SYMBOL(cpu_have_feature);
102 
show_facilities(struct seq_file * m)103 static void show_facilities(struct seq_file *m)
104 {
105 	unsigned int bit;
106 	long *facilities;
107 
108 	facilities = (long *)&S390_lowcore.stfle_fac_list;
109 	seq_puts(m, "facilities      :");
110 	for_each_set_bit_inv(bit, facilities, MAX_FACILITY_BIT)
111 		seq_printf(m, " %d", bit);
112 	seq_putc(m, '\n');
113 }
114 
show_cpu_summary(struct seq_file * m,void * v)115 static void show_cpu_summary(struct seq_file *m, void *v)
116 {
117 	static const char *hwcap_str[] = {
118 		"esan3", "zarch", "stfle", "msa", "ldisp", "eimm", "dfp",
119 		"edat", "etf3eh", "highgprs", "te", "vx", "vxd", "vxe", "gs",
120 		"vxe2", "vxp", "sort", "dflt"
121 	};
122 	static const char * const int_hwcap_str[] = {
123 		"sie"
124 	};
125 	int i, cpu;
126 
127 	seq_printf(m, "vendor_id       : IBM/S390\n"
128 		   "# processors    : %i\n"
129 		   "bogomips per cpu: %lu.%02lu\n",
130 		   num_online_cpus(), loops_per_jiffy/(500000/HZ),
131 		   (loops_per_jiffy/(5000/HZ))%100);
132 	seq_printf(m, "max thread id   : %d\n", smp_cpu_mtid);
133 	seq_puts(m, "features\t: ");
134 	for (i = 0; i < ARRAY_SIZE(hwcap_str); i++)
135 		if (hwcap_str[i] && (elf_hwcap & (1UL << i)))
136 			seq_printf(m, "%s ", hwcap_str[i]);
137 	for (i = 0; i < ARRAY_SIZE(int_hwcap_str); i++)
138 		if (int_hwcap_str[i] && (int_hwcap & (1UL << i)))
139 			seq_printf(m, "%s ", int_hwcap_str[i]);
140 	seq_puts(m, "\n");
141 	show_facilities(m);
142 	show_cacheinfo(m);
143 	for_each_online_cpu(cpu) {
144 		struct cpuid *id = &per_cpu(cpu_info.cpu_id, cpu);
145 
146 		seq_printf(m, "processor %d: "
147 			   "version = %02X,  "
148 			   "identification = %06X,  "
149 			   "machine = %04X\n",
150 			   cpu, id->version, id->ident, id->machine);
151 	}
152 }
153 
show_cpu_mhz(struct seq_file * m,unsigned long n)154 static void show_cpu_mhz(struct seq_file *m, unsigned long n)
155 {
156 	struct cpu_info *c = per_cpu_ptr(&cpu_info, n);
157 
158 	seq_printf(m, "cpu MHz dynamic : %d\n", c->cpu_mhz_dynamic);
159 	seq_printf(m, "cpu MHz static  : %d\n", c->cpu_mhz_static);
160 }
161 
162 /*
163  * show_cpuinfo - Get information on one CPU for use by procfs.
164  */
show_cpuinfo(struct seq_file * m,void * v)165 static int show_cpuinfo(struct seq_file *m, void *v)
166 {
167 	unsigned long n = (unsigned long) v - 1;
168 	unsigned long first = cpumask_first(cpu_online_mask);
169 
170 	if (n == first)
171 		show_cpu_summary(m, v);
172 	if (!machine_has_cpu_mhz)
173 		return 0;
174 	seq_printf(m, "\ncpu number      : %ld\n", n);
175 	show_cpu_mhz(m, n);
176 	return 0;
177 }
178 
c_update(loff_t * pos)179 static inline void *c_update(loff_t *pos)
180 {
181 	if (*pos)
182 		*pos = cpumask_next(*pos - 1, cpu_online_mask);
183 	else
184 		*pos = cpumask_first(cpu_online_mask);
185 	return *pos < nr_cpu_ids ? (void *)*pos + 1 : NULL;
186 }
187 
c_start(struct seq_file * m,loff_t * pos)188 static void *c_start(struct seq_file *m, loff_t *pos)
189 {
190 	get_online_cpus();
191 	return c_update(pos);
192 }
193 
c_next(struct seq_file * m,void * v,loff_t * pos)194 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
195 {
196 	++*pos;
197 	return c_update(pos);
198 }
199 
c_stop(struct seq_file * m,void * v)200 static void c_stop(struct seq_file *m, void *v)
201 {
202 	put_online_cpus();
203 }
204 
205 const struct seq_operations cpuinfo_op = {
206 	.start	= c_start,
207 	.next	= c_next,
208 	.stop	= c_stop,
209 	.show	= show_cpuinfo,
210 };
211 
s390_isolate_bp(void)212 int s390_isolate_bp(void)
213 {
214 	if (!test_facility(82))
215 		return -EOPNOTSUPP;
216 	set_thread_flag(TIF_ISOLATE_BP);
217 	return 0;
218 }
219 EXPORT_SYMBOL(s390_isolate_bp);
220 
s390_isolate_bp_guest(void)221 int s390_isolate_bp_guest(void)
222 {
223 	if (!test_facility(82))
224 		return -EOPNOTSUPP;
225 	set_thread_flag(TIF_ISOLATE_BP_GUEST);
226 	return 0;
227 }
228 EXPORT_SYMBOL(s390_isolate_bp_guest);
229