1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * CPU-Measurement Counter Facility Support - Common Layer
4 *
5 * Copyright IBM Corp. 2019
6 * Author(s): Hendrik Brueckner <brueckner@linux.ibm.com>
7 */
8 #define KMSG_COMPONENT "cpum_cf_common"
9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
10
11 #include <linux/kernel.h>
12 #include <linux/kernel_stat.h>
13 #include <linux/percpu.h>
14 #include <linux/notifier.h>
15 #include <linux/init.h>
16 #include <linux/export.h>
17 #include <asm/ctl_reg.h>
18 #include <asm/irq.h>
19 #include <asm/cpu_mcf.h>
20
21 /* Per-CPU event structure for the counter facility */
22 DEFINE_PER_CPU(struct cpu_cf_events, cpu_cf_events) = {
23 .ctr_set = {
24 [CPUMF_CTR_SET_BASIC] = ATOMIC_INIT(0),
25 [CPUMF_CTR_SET_USER] = ATOMIC_INIT(0),
26 [CPUMF_CTR_SET_CRYPTO] = ATOMIC_INIT(0),
27 [CPUMF_CTR_SET_EXT] = ATOMIC_INIT(0),
28 [CPUMF_CTR_SET_MT_DIAG] = ATOMIC_INIT(0),
29 },
30 .alert = ATOMIC64_INIT(0),
31 .state = 0,
32 .flags = 0,
33 .txn_flags = 0,
34 };
35 /* Indicator whether the CPU-Measurement Counter Facility Support is ready */
36 static bool cpum_cf_initalized;
37
38 /* CPU-measurement alerts for the counter facility */
cpumf_measurement_alert(struct ext_code ext_code,unsigned int alert,unsigned long unused)39 static void cpumf_measurement_alert(struct ext_code ext_code,
40 unsigned int alert, unsigned long unused)
41 {
42 struct cpu_cf_events *cpuhw;
43
44 if (!(alert & CPU_MF_INT_CF_MASK))
45 return;
46
47 inc_irq_stat(IRQEXT_CMC);
48 cpuhw = this_cpu_ptr(&cpu_cf_events);
49
50 /* Measurement alerts are shared and might happen when the PMU
51 * is not reserved. Ignore these alerts in this case. */
52 if (!(cpuhw->flags & PMU_F_RESERVED))
53 return;
54
55 /* counter authorization change alert */
56 if (alert & CPU_MF_INT_CF_CACA)
57 qctri(&cpuhw->info);
58
59 /* loss of counter data alert */
60 if (alert & CPU_MF_INT_CF_LCDA)
61 pr_err("CPU[%i] Counter data was lost\n", smp_processor_id());
62
63 /* loss of MT counter data alert */
64 if (alert & CPU_MF_INT_CF_MTDA)
65 pr_warn("CPU[%i] MT counter data was lost\n",
66 smp_processor_id());
67
68 /* store alert for special handling by in-kernel users */
69 atomic64_or(alert, &cpuhw->alert);
70 }
71
72 #define PMC_INIT 0
73 #define PMC_RELEASE 1
cpum_cf_setup_cpu(void * flags)74 static void cpum_cf_setup_cpu(void *flags)
75 {
76 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
77
78 switch (*((int *) flags)) {
79 case PMC_INIT:
80 memset(&cpuhw->info, 0, sizeof(cpuhw->info));
81 qctri(&cpuhw->info);
82 cpuhw->flags |= PMU_F_RESERVED;
83 break;
84
85 case PMC_RELEASE:
86 cpuhw->flags &= ~PMU_F_RESERVED;
87 break;
88 }
89
90 /* Disable CPU counter sets */
91 lcctl(0);
92 }
93
kernel_cpumcf_avail(void)94 bool kernel_cpumcf_avail(void)
95 {
96 return cpum_cf_initalized;
97 }
98 EXPORT_SYMBOL(kernel_cpumcf_avail);
99
100
101 /* Reserve/release functions for sharing perf hardware */
102 static DEFINE_SPINLOCK(cpumcf_owner_lock);
103 static void *cpumcf_owner;
104
105 /* Initialize the CPU-measurement counter facility */
__kernel_cpumcf_begin(void)106 int __kernel_cpumcf_begin(void)
107 {
108 int flags = PMC_INIT;
109 int err = 0;
110
111 spin_lock(&cpumcf_owner_lock);
112 if (cpumcf_owner)
113 err = -EBUSY;
114 else
115 cpumcf_owner = __builtin_return_address(0);
116 spin_unlock(&cpumcf_owner_lock);
117 if (err)
118 return err;
119
120 on_each_cpu(cpum_cf_setup_cpu, &flags, 1);
121 irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT);
122
123 return 0;
124 }
125 EXPORT_SYMBOL(__kernel_cpumcf_begin);
126
127 /* Obtain the CPU-measurement alerts for the counter facility */
kernel_cpumcf_alert(int clear)128 unsigned long kernel_cpumcf_alert(int clear)
129 {
130 struct cpu_cf_events *cpuhw = this_cpu_ptr(&cpu_cf_events);
131 unsigned long alert;
132
133 alert = atomic64_read(&cpuhw->alert);
134 if (clear)
135 atomic64_set(&cpuhw->alert, 0);
136
137 return alert;
138 }
139 EXPORT_SYMBOL(kernel_cpumcf_alert);
140
141 /* Release the CPU-measurement counter facility */
__kernel_cpumcf_end(void)142 void __kernel_cpumcf_end(void)
143 {
144 int flags = PMC_RELEASE;
145
146 on_each_cpu(cpum_cf_setup_cpu, &flags, 1);
147 irq_subclass_unregister(IRQ_SUBCLASS_MEASUREMENT_ALERT);
148
149 spin_lock(&cpumcf_owner_lock);
150 cpumcf_owner = NULL;
151 spin_unlock(&cpumcf_owner_lock);
152 }
153 EXPORT_SYMBOL(__kernel_cpumcf_end);
154
cpum_cf_setup(unsigned int cpu,int flags)155 static int cpum_cf_setup(unsigned int cpu, int flags)
156 {
157 local_irq_disable();
158 cpum_cf_setup_cpu(&flags);
159 local_irq_enable();
160 return 0;
161 }
162
cpum_cf_online_cpu(unsigned int cpu)163 static int cpum_cf_online_cpu(unsigned int cpu)
164 {
165 return cpum_cf_setup(cpu, PMC_INIT);
166 }
167
cpum_cf_offline_cpu(unsigned int cpu)168 static int cpum_cf_offline_cpu(unsigned int cpu)
169 {
170 return cpum_cf_setup(cpu, PMC_RELEASE);
171 }
172
cpum_cf_init(void)173 static int __init cpum_cf_init(void)
174 {
175 int rc;
176
177 if (!cpum_cf_avail())
178 return -ENODEV;
179
180 /* clear bit 15 of cr0 to unauthorize problem-state to
181 * extract measurement counters */
182 ctl_clear_bit(0, 48);
183
184 /* register handler for measurement-alert interruptions */
185 rc = register_external_irq(EXT_IRQ_MEASURE_ALERT,
186 cpumf_measurement_alert);
187 if (rc) {
188 pr_err("Registering for CPU-measurement alerts "
189 "failed with rc=%i\n", rc);
190 return rc;
191 }
192
193 rc = cpuhp_setup_state(CPUHP_AP_PERF_S390_CF_ONLINE,
194 "perf/s390/cf:online",
195 cpum_cf_online_cpu, cpum_cf_offline_cpu);
196 if (!rc)
197 cpum_cf_initalized = true;
198
199 return rc;
200 }
201 early_initcall(cpum_cf_init);
202
