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/export.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/perf_event.h>
23 #include <asm/ptrace.h>
28 /* We don't have a real NMI on sparc64, but we can fake one
29 * up using profiling counter overflow interrupts and interrupt
32 * The profile overflow interrupts at level 15, so we use
33 * level 14 as our IRQ off level.
36 static int panic_on_timeout
;
39 * >0: the NMI watchdog is active, but can be disabled
40 * <0: the NMI watchdog has not been set up, and cannot be enabled
41 * 0: the NMI watchdog is disabled, but can be enabled
43 atomic_t nmi_active
= ATOMIC_INIT(0); /* oprofile uses this */
44 EXPORT_SYMBOL(nmi_active
);
45 static int nmi_init_done
;
46 static unsigned int nmi_hz
= HZ
;
47 static DEFINE_PER_CPU(short, wd_enabled
);
48 static int endflag __initdata
;
50 static DEFINE_PER_CPU(unsigned int, last_irq_sum
);
51 static DEFINE_PER_CPU(long, alert_counter
);
52 static DEFINE_PER_CPU(int, nmi_touch
);
54 void arch_touch_nmi_watchdog(void)
56 if (atomic_read(&nmi_active
)) {
59 for_each_present_cpu(cpu
) {
60 if (per_cpu(nmi_touch
, cpu
) != 1)
61 per_cpu(nmi_touch
, cpu
) = 1;
65 EXPORT_SYMBOL(arch_touch_nmi_watchdog
);
67 static void die_nmi(const char *str
, struct pt_regs
*regs
, int do_panic
)
69 int this_cpu
= smp_processor_id();
71 if (notify_die(DIE_NMIWATCHDOG
, str
, regs
, 0,
72 pt_regs_trap_type(regs
), SIGINT
) == NOTIFY_STOP
)
75 if (do_panic
|| panic_on_oops
)
76 panic("Watchdog detected hard LOCKUP on cpu %d", this_cpu
);
78 WARN(1, "Watchdog detected hard LOCKUP on cpu %d", this_cpu
);
81 notrace __kprobes
void perfctr_irq(int irq
, struct pt_regs
*regs
)
83 unsigned int sum
, touched
= 0;
86 clear_softint(1 << irq
);
88 local_cpu_data().__nmi_count
++;
92 orig_sp
= set_hardirq_stack();
94 if (notify_die(DIE_NMI
, "nmi", regs
, 0,
95 pt_regs_trap_type(regs
), SIGINT
) == NOTIFY_STOP
)
98 pcr_ops
->write_pcr(0, pcr_ops
->pcr_nmi_disable
);
100 sum
= local_cpu_data().irq0_irqs
;
101 if (__this_cpu_read(nmi_touch
)) {
102 __this_cpu_write(nmi_touch
, 0);
105 if (!touched
&& __this_cpu_read(last_irq_sum
) == sum
) {
106 __this_cpu_inc(alert_counter
);
107 if (__this_cpu_read(alert_counter
) == 30 * nmi_hz
)
108 die_nmi("BUG: NMI Watchdog detected LOCKUP",
109 regs
, panic_on_timeout
);
111 __this_cpu_write(last_irq_sum
, sum
);
112 __this_cpu_write(alert_counter
, 0);
114 if (__this_cpu_read(wd_enabled
)) {
115 pcr_ops
->write_pic(0, pcr_ops
->nmi_picl_value(nmi_hz
));
116 pcr_ops
->write_pcr(0, pcr_ops
->pcr_nmi_enable
);
119 restore_hardirq_stack(orig_sp
);
124 static inline unsigned int get_nmi_count(int cpu
)
126 return cpu_data(cpu
).__nmi_count
;
129 static __init
void nmi_cpu_busy(void *data
)
135 static void report_broken_nmi(int cpu
, int *prev_nmi_count
)
137 printk(KERN_CONT
"\n");
140 "WARNING: CPU#%d: NMI appears to be stuck (%d->%d)!\n",
141 cpu
, prev_nmi_count
[cpu
], get_nmi_count(cpu
));
144 "Please report this to bugzilla.kernel.org,\n");
146 "and attach the output of the 'dmesg' command.\n");
148 per_cpu(wd_enabled
, cpu
) = 0;
149 atomic_dec(&nmi_active
);
152 void stop_nmi_watchdog(void *unused
)
154 if (!__this_cpu_read(wd_enabled
))
156 pcr_ops
->write_pcr(0, pcr_ops
->pcr_nmi_disable
);
157 __this_cpu_write(wd_enabled
, 0);
158 atomic_dec(&nmi_active
);
161 static int __init
check_nmi_watchdog(void)
163 unsigned int *prev_nmi_count
;
166 if (!atomic_read(&nmi_active
))
169 prev_nmi_count
= kmalloc(nr_cpu_ids
* sizeof(unsigned int), GFP_KERNEL
);
170 if (!prev_nmi_count
) {
175 printk(KERN_INFO
"Testing NMI watchdog ... ");
177 smp_call_function(nmi_cpu_busy
, (void *)&endflag
, 0);
179 for_each_possible_cpu(cpu
)
180 prev_nmi_count
[cpu
] = get_nmi_count(cpu
);
182 mdelay((20 * 1000) / nmi_hz
); /* wait 20 ticks */
184 for_each_online_cpu(cpu
) {
185 if (!per_cpu(wd_enabled
, cpu
))
187 if (get_nmi_count(cpu
) - prev_nmi_count
[cpu
] <= 5)
188 report_broken_nmi(cpu
, prev_nmi_count
);
191 if (!atomic_read(&nmi_active
)) {
192 kfree(prev_nmi_count
);
193 atomic_set(&nmi_active
, -1);
201 kfree(prev_nmi_count
);
204 on_each_cpu(stop_nmi_watchdog
, NULL
, 1);
208 void start_nmi_watchdog(void *unused
)
210 if (__this_cpu_read(wd_enabled
))
213 __this_cpu_write(wd_enabled
, 1);
214 atomic_inc(&nmi_active
);
216 pcr_ops
->write_pcr(0, pcr_ops
->pcr_nmi_disable
);
217 pcr_ops
->write_pic(0, pcr_ops
->nmi_picl_value(nmi_hz
));
219 pcr_ops
->write_pcr(0, pcr_ops
->pcr_nmi_enable
);
222 static void nmi_adjust_hz_one(void *unused
)
224 if (!__this_cpu_read(wd_enabled
))
227 pcr_ops
->write_pcr(0, pcr_ops
->pcr_nmi_disable
);
228 pcr_ops
->write_pic(0, pcr_ops
->nmi_picl_value(nmi_hz
));
230 pcr_ops
->write_pcr(0, pcr_ops
->pcr_nmi_enable
);
233 void nmi_adjust_hz(unsigned int new_hz
)
236 on_each_cpu(nmi_adjust_hz_one
, NULL
, 1);
238 EXPORT_SYMBOL_GPL(nmi_adjust_hz
);
240 static int nmi_shutdown(struct notifier_block
*nb
, unsigned long cmd
, void *p
)
242 on_each_cpu(stop_nmi_watchdog
, NULL
, 1);
246 static struct notifier_block nmi_reboot_notifier
= {
247 .notifier_call
= nmi_shutdown
,
250 int __init
nmi_init(void)
254 on_each_cpu(start_nmi_watchdog
, NULL
, 1);
256 err
= check_nmi_watchdog();
258 err
= register_reboot_notifier(&nmi_reboot_notifier
);
260 on_each_cpu(stop_nmi_watchdog
, NULL
, 1);
261 atomic_set(&nmi_active
, -1);
270 static int __init
setup_nmi_watchdog(char *str
)
272 if (!strncmp(str
, "panic", 5))
273 panic_on_timeout
= 1;
277 __setup("nmi_watchdog=", setup_nmi_watchdog
);
280 * sparc specific NMI watchdog enable function.
281 * Enables watchdog if it is not enabled already.
283 int watchdog_nmi_enable(unsigned int cpu
)
285 if (atomic_read(&nmi_active
) == -1) {
286 pr_warn("NMI watchdog cannot be enabled or disabled\n");
291 * watchdog thread could start even before nmi_init is called.
292 * Just Return in that case. Let nmi_init finish the init
298 smp_call_function_single(cpu
, start_nmi_watchdog
, NULL
, 1);
303 * sparc specific NMI watchdog disable function.
304 * Disables watchdog if it is not disabled already.
306 void watchdog_nmi_disable(unsigned int cpu
)
308 if (atomic_read(&nmi_active
) == -1)
309 pr_warn_once("NMI watchdog cannot be enabled or disabled\n");
311 smp_call_function_single(cpu
, stop_nmi_watchdog
, NULL
, 1);