1 /* Pseudo NMI support on sparc64 systems.
3 * Copyright (C) 2009 David S. Miller <davem@davemloft.net>
5 * The NMI watchdog support and infrastructure is based almost
6 * entirely upon the x86 NMI support code.
8 #include <linux/kernel.h>
9 #include <linux/param.h>
10 #include <linux/init.h>
11 #include <linux/percpu.h>
12 #include <linux/nmi.h>
13 #include <linux/module.h>
14 #include <linux/kprobes.h>
15 #include <linux/kernel_stat.h>
16 #include <linux/reboot.h>
17 #include <linux/slab.h>
18 #include <linux/kdebug.h>
19 #include <linux/delay.h>
20 #include <linux/smp.h>
22 #include <asm/ptrace.h>
23 #include <asm/local.h>
26 /* We don't have a real NMI on sparc64, but we can fake one
27 * up using profiling counter overflow interrupts and interrupt
30 * The profile overflow interrupts at level 15, so we use
31 * level 14 as our IRQ off level.
34 static int nmi_watchdog_active
;
35 static int panic_on_timeout
;
38 * >0: the NMI watchdog is active, but can be disabled
39 * <0: the NMI watchdog has not been set up, and cannot be enabled
40 * 0: the NMI watchdog is disabled, but can be enabled
42 atomic_t nmi_active
= ATOMIC_INIT(0); /* oprofile uses this */
43 EXPORT_SYMBOL(nmi_active
);
45 static unsigned int nmi_hz
= HZ
;
46 static DEFINE_PER_CPU(short, wd_enabled
);
47 static int endflag __initdata
;
49 static DEFINE_PER_CPU(unsigned int, last_irq_sum
);
50 static DEFINE_PER_CPU(local_t
, alert_counter
);
51 static DEFINE_PER_CPU(int, nmi_touch
);
53 void touch_nmi_watchdog(void)
55 if (nmi_watchdog_active
) {
58 for_each_present_cpu(cpu
) {
59 if (per_cpu(nmi_touch
, cpu
) != 1)
60 per_cpu(nmi_touch
, cpu
) = 1;
64 touch_softlockup_watchdog();
66 EXPORT_SYMBOL(touch_nmi_watchdog
);
68 static void die_nmi(const char *str
, struct pt_regs
*regs
, int do_panic
)
70 if (notify_die(DIE_NMIWATCHDOG
, str
, regs
, 0,
71 pt_regs_trap_type(regs
), SIGINT
) == NOTIFY_STOP
)
77 printk(KERN_EMERG
"%s", str
);
78 printk(" on CPU%d, ip %08lx, registers:\n",
79 smp_processor_id(), regs
->tpc
);
85 if (do_panic
|| panic_on_oops
)
86 panic("Non maskable interrupt");
92 notrace __kprobes
void perfctr_irq(int irq
, struct pt_regs
*regs
)
94 unsigned int sum
, touched
= 0;
95 int cpu
= smp_processor_id();
97 clear_softint(1 << irq
);
98 pcr_ops
->write(PCR_PIC_PRIV
);
100 local_cpu_data().__nmi_count
++;
102 if (notify_die(DIE_NMI
, "nmi", regs
, 0,
103 pt_regs_trap_type(regs
), SIGINT
) == NOTIFY_STOP
)
106 sum
= kstat_irqs_cpu(0, cpu
);
107 if (__get_cpu_var(nmi_touch
)) {
108 __get_cpu_var(nmi_touch
) = 0;
111 if (!touched
&& __get_cpu_var(last_irq_sum
) == sum
) {
112 local_inc(&__get_cpu_var(alert_counter
));
113 if (local_read(&__get_cpu_var(alert_counter
)) == 5 * nmi_hz
)
114 die_nmi("BUG: NMI Watchdog detected LOCKUP",
115 regs
, panic_on_timeout
);
117 __get_cpu_var(last_irq_sum
) = sum
;
118 local_set(&__get_cpu_var(alert_counter
), 0);
120 if (__get_cpu_var(wd_enabled
)) {
121 write_pic(picl_value(nmi_hz
));
122 pcr_ops
->write(pcr_enable
);
126 static inline unsigned int get_nmi_count(int cpu
)
128 return cpu_data(cpu
).__nmi_count
;
131 static __init
void nmi_cpu_busy(void *data
)
133 local_irq_enable_in_hardirq();
138 static void report_broken_nmi(int cpu
, int *prev_nmi_count
)
140 printk(KERN_CONT
"\n");
143 "WARNING: CPU#%d: NMI appears to be stuck (%d->%d)!\n",
144 cpu
, prev_nmi_count
[cpu
], get_nmi_count(cpu
));
147 "Please report this to bugzilla.kernel.org,\n");
149 "and attach the output of the 'dmesg' command.\n");
151 per_cpu(wd_enabled
, cpu
) = 0;
152 atomic_dec(&nmi_active
);
155 static void stop_nmi_watchdog(void *unused
)
157 pcr_ops
->write(PCR_PIC_PRIV
);
158 __get_cpu_var(wd_enabled
) = 0;
159 atomic_dec(&nmi_active
);
162 static int __init
check_nmi_watchdog(void)
164 unsigned int *prev_nmi_count
;
167 if (!atomic_read(&nmi_active
))
170 prev_nmi_count
= kmalloc(nr_cpu_ids
* sizeof(unsigned int), GFP_KERNEL
);
171 if (!prev_nmi_count
) {
176 printk(KERN_INFO
"Testing NMI watchdog ... ");
178 smp_call_function(nmi_cpu_busy
, (void *)&endflag
, 0);
180 for_each_possible_cpu(cpu
)
181 prev_nmi_count
[cpu
] = get_nmi_count(cpu
);
183 mdelay((20 * 1000) / nmi_hz
); /* wait 20 ticks */
185 for_each_online_cpu(cpu
) {
186 if (!per_cpu(wd_enabled
, cpu
))
188 if (get_nmi_count(cpu
) - prev_nmi_count
[cpu
] <= 5)
189 report_broken_nmi(cpu
, prev_nmi_count
);
192 if (!atomic_read(&nmi_active
)) {
193 kfree(prev_nmi_count
);
194 atomic_set(&nmi_active
, -1);
202 kfree(prev_nmi_count
);
205 on_each_cpu(stop_nmi_watchdog
, NULL
, 1);
209 static void start_nmi_watchdog(void *unused
)
211 __get_cpu_var(wd_enabled
) = 1;
212 atomic_inc(&nmi_active
);
214 pcr_ops
->write(PCR_PIC_PRIV
);
215 write_pic(picl_value(nmi_hz
));
217 pcr_ops
->write(pcr_enable
);
220 static void nmi_adjust_hz_one(void *unused
)
222 if (!__get_cpu_var(wd_enabled
))
225 pcr_ops
->write(PCR_PIC_PRIV
);
226 write_pic(picl_value(nmi_hz
));
228 pcr_ops
->write(pcr_enable
);
231 void nmi_adjust_hz(unsigned int new_hz
)
234 on_each_cpu(nmi_adjust_hz_one
, NULL
, 1);
236 EXPORT_SYMBOL_GPL(nmi_adjust_hz
);
238 static int nmi_shutdown(struct notifier_block
*nb
, unsigned long cmd
, void *p
)
240 on_each_cpu(stop_nmi_watchdog
, NULL
, 1);
244 static struct notifier_block nmi_reboot_notifier
= {
245 .notifier_call
= nmi_shutdown
,
248 int __init
nmi_init(void)
252 on_each_cpu(start_nmi_watchdog
, NULL
, 1);
254 err
= check_nmi_watchdog();
256 err
= register_reboot_notifier(&nmi_reboot_notifier
);
258 on_each_cpu(stop_nmi_watchdog
, NULL
, 1);
259 atomic_set(&nmi_active
, -1);
265 static int __init
setup_nmi_watchdog(char *str
)
267 if (!strncmp(str
, "panic", 5))
268 panic_on_timeout
= 1;
272 __setup("nmi_watchdog=", setup_nmi_watchdog
);