1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
|
/*
* Intel specific MCE features.
* Copyright 2004 Zwane Mwaikambo <zwane@linuxpower.ca>
* Copyright (C) 2008, 2009 Intel Corporation
* Author: Andi Kleen
*/
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/percpu.h>
#include <linux/sched.h>
#include <asm/apic.h>
#include <asm/processor.h>
#include <asm/msr.h>
#include <asm/mce.h>
/*
* Support for Intel Correct Machine Check Interrupts. This allows
* the CPU to raise an interrupt when a corrected machine check happened.
* Normally we pick those up using a regular polling timer.
* Also supports reliable discovery of shared banks.
*/
static DEFINE_PER_CPU(mce_banks_t, mce_banks_owned);
/*
* cmci_discover_lock protects against parallel discovery attempts
* which could race against each other.
*/
static DEFINE_SPINLOCK(cmci_discover_lock);
#define CMCI_THRESHOLD 1
static int cmci_supported(int *banks)
{
u64 cap;
if (mce_cmci_disabled || mce_ignore_ce)
return 0;
/*
* Vendor check is not strictly needed, but the initial
* initialization is vendor keyed and this
* makes sure none of the backdoors are entered otherwise.
*/
if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
return 0;
if (!cpu_has_apic || lapic_get_maxlvt() < 6)
return 0;
rdmsrl(MSR_IA32_MCG_CAP, cap);
*banks = min_t(unsigned, MAX_NR_BANKS, cap & 0xff);
return !!(cap & MCG_CMCI_P);
}
/*
* The interrupt handler. This is called on every event.
* Just call the poller directly to log any events.
* This could in theory increase the threshold under high load,
* but doesn't for now.
*/
static void intel_threshold_interrupt(void)
{
machine_check_poll(MCP_TIMESTAMP, &__get_cpu_var(mce_banks_owned));
mce_notify_irq();
}
static void print_update(char *type, int *hdr, int num)
{
if (*hdr == 0)
printk(KERN_INFO "CPU %d MCA banks", smp_processor_id());
*hdr = 1;
printk(KERN_CONT " %s:%d", type, num);
}
/*
* Enable CMCI (Corrected Machine Check Interrupt) for available MCE banks
* on this CPU. Use the algorithm recommended in the SDM to discover shared
* banks.
*/
static void cmci_discover(int banks, int boot)
{
unsigned long *owned = (void *)&__get_cpu_var(mce_banks_owned);
unsigned long flags;
int hdr = 0;
int i;
spin_lock_irqsave(&cmci_discover_lock, flags);
for (i = 0; i < banks; i++) {
u64 val;
if (test_bit(i, owned))
continue;
rdmsrl(MSR_IA32_MCx_CTL2(i), val);
/* Already owned by someone else? */
if (val & CMCI_EN) {
if (test_and_clear_bit(i, owned) && !boot)
print_update("SHD", &hdr, i);
__clear_bit(i, __get_cpu_var(mce_poll_banks));
continue;
}
val |= CMCI_EN | CMCI_THRESHOLD;
wrmsrl(MSR_IA32_MCx_CTL2(i), val);
rdmsrl(MSR_IA32_MCx_CTL2(i), val);
/* Did the enable bit stick? -- the bank supports CMCI */
if (val & CMCI_EN) {
if (!test_and_set_bit(i, owned) && !boot)
print_update("CMCI", &hdr, i);
__clear_bit(i, __get_cpu_var(mce_poll_banks));
} else {
WARN_ON(!test_bit(i, __get_cpu_var(mce_poll_banks)));
}
}
spin_unlock_irqrestore(&cmci_discover_lock, flags);
if (hdr)
printk(KERN_CONT "\n");
}
/*
* Just in case we missed an event during initialization check
* all the CMCI owned banks.
*/
void cmci_recheck(void)
{
unsigned long flags;
int banks;
if (!mce_available(¤t_cpu_data) || !cmci_supported(&banks))
return;
local_irq_save(flags);
machine_check_poll(MCP_TIMESTAMP, &__get_cpu_var(mce_banks_owned));
local_irq_restore(flags);
}
/*
* Disable CMCI on this CPU for all banks it owns when it goes down.
* This allows other CPUs to claim the banks on rediscovery.
*/
void cmci_clear(void)
{
unsigned long flags;
int i;
int banks;
u64 val;
if (!cmci_supported(&banks))
return;
spin_lock_irqsave(&cmci_discover_lock, flags);
for (i = 0; i < banks; i++) {
if (!test_bit(i, __get_cpu_var(mce_banks_owned)))
continue;
/* Disable CMCI */
rdmsrl(MSR_IA32_MCx_CTL2(i), val);
val &= ~(CMCI_EN|CMCI_THRESHOLD_MASK);
wrmsrl(MSR_IA32_MCx_CTL2(i), val);
__clear_bit(i, __get_cpu_var(mce_banks_owned));
}
spin_unlock_irqrestore(&cmci_discover_lock, flags);
}
/*
* After a CPU went down cycle through all the others and rediscover
* Must run in process context.
*/
void cmci_rediscover(int dying)
{
int banks;
int cpu;
cpumask_var_t old;
if (!cmci_supported(&banks))
return;
if (!alloc_cpumask_var(&old, GFP_KERNEL))
return;
cpumask_copy(old, ¤t->cpus_allowed);
for_each_online_cpu(cpu) {
if (cpu == dying)
continue;
if (set_cpus_allowed_ptr(current, cpumask_of(cpu)))
continue;
/* Recheck banks in case CPUs don't all have the same */
if (cmci_supported(&banks))
cmci_discover(banks, 0);
}
set_cpus_allowed_ptr(current, old);
free_cpumask_var(old);
}
/*
* Reenable CMCI on this CPU in case a CPU down failed.
*/
void cmci_reenable(void)
{
int banks;
if (cmci_supported(&banks))
cmci_discover(banks, 0);
}
static void intel_init_cmci(void)
{
int banks;
if (!cmci_supported(&banks))
return;
mce_threshold_vector = intel_threshold_interrupt;
cmci_discover(banks, 1);
/*
* For CPU #0 this runs with still disabled APIC, but that's
* ok because only the vector is set up. We still do another
* check for the banks later for CPU #0 just to make sure
* to not miss any events.
*/
apic_write(APIC_LVTCMCI, THRESHOLD_APIC_VECTOR|APIC_DM_FIXED);
cmci_recheck();
}
void mce_intel_feature_init(struct cpuinfo_x86 *c)
{
intel_init_thermal(c);
intel_init_cmci();
}
|
