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
|
/* Pseudo NMI support on sparc64 systems.
*
* Copyright (C) 2009 David S. Miller <davem@davemloft.net>
*
* The NMI watchdog support and infrastructure is based almost
* entirely upon the x86 NMI support code.
*/
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/init.h>
#include <linux/percpu.h>
#include <linux/nmi.h>
#include <linux/module.h>
#include <linux/kprobes.h>
#include <linux/kernel_stat.h>
#include <linux/slab.h>
#include <linux/kdebug.h>
#include <linux/delay.h>
#include <linux/smp.h>
#include <asm/ptrace.h>
#include <asm/local.h>
#include <asm/pcr.h>
/* We don't have a real NMI on sparc64, but we can fake one
* up using profiling counter overflow interrupts and interrupt
* levels.
*
* The profile overflow interrupts at level 15, so we use
* level 14 as our IRQ off level.
*/
static int nmi_watchdog_active;
static int panic_on_timeout;
int nmi_usable;
EXPORT_SYMBOL_GPL(nmi_usable);
static unsigned int nmi_hz = HZ;
static DEFINE_PER_CPU(unsigned int, last_irq_sum);
static DEFINE_PER_CPU(local_t, alert_counter);
static DEFINE_PER_CPU(int, nmi_touch);
void touch_nmi_watchdog(void)
{
if (nmi_watchdog_active) {
int cpu;
for_each_present_cpu(cpu) {
if (per_cpu(nmi_touch, cpu) != 1)
per_cpu(nmi_touch, cpu) = 1;
}
}
touch_softlockup_watchdog();
}
EXPORT_SYMBOL(touch_nmi_watchdog);
static void die_nmi(const char *str, struct pt_regs *regs, int do_panic)
{
if (notify_die(DIE_NMIWATCHDOG, str, regs, 0,
pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP)
return;
console_verbose();
bust_spinlocks(1);
printk(KERN_EMERG "%s", str);
printk(" on CPU%d, ip %08lx, registers:\n",
smp_processor_id(), regs->tpc);
show_regs(regs);
bust_spinlocks(0);
if (do_panic || panic_on_oops)
panic("Non maskable interrupt");
local_irq_enable();
do_exit(SIGBUS);
}
notrace __kprobes void perfctr_irq(int irq, struct pt_regs *regs)
{
unsigned int sum, touched = 0;
int cpu = smp_processor_id();
clear_softint(1 << irq);
pcr_ops->write(PCR_PIC_PRIV);
local_cpu_data().__nmi_count++;
if (notify_die(DIE_NMI, "nmi", regs, 0,
pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP)
touched = 1;
sum = kstat_cpu(cpu).irqs[0];
if (__get_cpu_var(nmi_touch)) {
__get_cpu_var(nmi_touch) = 0;
touched = 1;
}
if (!touched && __get_cpu_var(last_irq_sum) == sum) {
local_inc(&__get_cpu_var(alert_counter));
if (local_read(&__get_cpu_var(alert_counter)) == 5 * nmi_hz)
die_nmi("BUG: NMI Watchdog detected LOCKUP",
regs, panic_on_timeout);
} else {
__get_cpu_var(last_irq_sum) = sum;
local_set(&__get_cpu_var(alert_counter), 0);
}
if (nmi_usable) {
write_pic(picl_value(nmi_hz));
pcr_ops->write(pcr_enable);
}
}
static inline unsigned int get_nmi_count(int cpu)
{
return cpu_data(cpu).__nmi_count;
}
static int endflag __initdata;
static __init void nmi_cpu_busy(void *data)
{
local_irq_enable_in_hardirq();
while (endflag == 0)
mb();
}
static void report_broken_nmi(int cpu, int *prev_nmi_count)
{
printk(KERN_CONT "\n");
printk(KERN_WARNING
"WARNING: CPU#%d: NMI appears to be stuck (%d->%d)!\n",
cpu, prev_nmi_count[cpu], get_nmi_count(cpu));
printk(KERN_WARNING
"Please report this to bugzilla.kernel.org,\n");
printk(KERN_WARNING
"and attach the output of the 'dmesg' command.\n");
nmi_usable = 0;
}
static void stop_watchdog(void *unused)
{
pcr_ops->write(PCR_PIC_PRIV);
}
static int __init check_nmi_watchdog(void)
{
unsigned int *prev_nmi_count;
int cpu, err;
prev_nmi_count = kmalloc(nr_cpu_ids * sizeof(unsigned int), GFP_KERNEL);
if (!prev_nmi_count) {
err = -ENOMEM;
goto error;
}
printk(KERN_INFO "Testing NMI watchdog ... ");
smp_call_function(nmi_cpu_busy, (void *)&endflag, 0);
for_each_possible_cpu(cpu)
prev_nmi_count[cpu] = get_nmi_count(cpu);
local_irq_enable();
mdelay((20 * 1000) / nmi_hz); /* wait 20 ticks */
for_each_online_cpu(cpu) {
if (get_nmi_count(cpu) - prev_nmi_count[cpu] <= 5)
report_broken_nmi(cpu, prev_nmi_count);
}
endflag = 1;
if (!nmi_usable) {
kfree(prev_nmi_count);
err = -ENODEV;
goto error;
}
printk("OK.\n");
nmi_hz = 1;
kfree(prev_nmi_count);
return 0;
error:
on_each_cpu(stop_watchdog, NULL, 1);
return err;
}
static void start_watchdog(void *unused)
{
pcr_ops->write(PCR_PIC_PRIV);
write_pic(picl_value(nmi_hz));
pcr_ops->write(pcr_enable);
}
void nmi_adjust_hz(unsigned int new_hz)
{
nmi_hz = new_hz;
on_each_cpu(start_watchdog, NULL, 1);
}
EXPORT_SYMBOL_GPL(nmi_adjust_hz);
int __init nmi_init(void)
{
nmi_usable = 1;
on_each_cpu(start_watchdog, NULL, 1);
return check_nmi_watchdog();
}
static int __init setup_nmi_watchdog(char *str)
{
if (!strncmp(str, "panic", 5))
panic_on_timeout = 1;
return 0;
}
__setup("nmi_watchdog=", setup_nmi_watchdog);
|
