Linux 2.6.31.6
[linux/fpc-iii.git] / arch / sparc / kernel / nmi.c
blobb75bf502cd424e7305959c2ca92bffd4cc88bcf4
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.
7 */
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>
24 #include <asm/pcr.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
28 * levels.
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;
37 int nmi_usable;
38 EXPORT_SYMBOL_GPL(nmi_usable);
40 static unsigned int nmi_hz = HZ;
42 static DEFINE_PER_CPU(unsigned int, last_irq_sum);
43 static DEFINE_PER_CPU(local_t, alert_counter);
44 static DEFINE_PER_CPU(int, nmi_touch);
46 void touch_nmi_watchdog(void)
48 if (nmi_watchdog_active) {
49 int cpu;
51 for_each_present_cpu(cpu) {
52 if (per_cpu(nmi_touch, cpu) != 1)
53 per_cpu(nmi_touch, cpu) = 1;
57 touch_softlockup_watchdog();
59 EXPORT_SYMBOL(touch_nmi_watchdog);
61 static void die_nmi(const char *str, struct pt_regs *regs, int do_panic)
63 if (notify_die(DIE_NMIWATCHDOG, str, regs, 0,
64 pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP)
65 return;
67 console_verbose();
68 bust_spinlocks(1);
70 printk(KERN_EMERG "%s", str);
71 printk(" on CPU%d, ip %08lx, registers:\n",
72 smp_processor_id(), regs->tpc);
73 show_regs(regs);
74 dump_stack();
76 bust_spinlocks(0);
78 if (do_panic || panic_on_oops)
79 panic("Non maskable interrupt");
81 local_irq_enable();
82 do_exit(SIGBUS);
85 notrace __kprobes void perfctr_irq(int irq, struct pt_regs *regs)
87 unsigned int sum, touched = 0;
88 int cpu = smp_processor_id();
90 clear_softint(1 << irq);
91 pcr_ops->write(PCR_PIC_PRIV);
93 local_cpu_data().__nmi_count++;
95 if (notify_die(DIE_NMI, "nmi", regs, 0,
96 pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP)
97 touched = 1;
99 sum = kstat_irqs_cpu(0, cpu);
100 if (__get_cpu_var(nmi_touch)) {
101 __get_cpu_var(nmi_touch) = 0;
102 touched = 1;
104 if (!touched && __get_cpu_var(last_irq_sum) == sum) {
105 local_inc(&__get_cpu_var(alert_counter));
106 if (local_read(&__get_cpu_var(alert_counter)) == 30 * nmi_hz)
107 die_nmi("BUG: NMI Watchdog detected LOCKUP",
108 regs, panic_on_timeout);
109 } else {
110 __get_cpu_var(last_irq_sum) = sum;
111 local_set(&__get_cpu_var(alert_counter), 0);
113 if (nmi_usable) {
114 write_pic(picl_value(nmi_hz));
115 pcr_ops->write(pcr_enable);
119 static inline unsigned int get_nmi_count(int cpu)
121 return cpu_data(cpu).__nmi_count;
124 static int endflag __initdata;
126 static __init void nmi_cpu_busy(void *data)
128 local_irq_enable_in_hardirq();
129 while (endflag == 0)
130 mb();
133 static void report_broken_nmi(int cpu, int *prev_nmi_count)
135 printk(KERN_CONT "\n");
137 printk(KERN_WARNING
138 "WARNING: CPU#%d: NMI appears to be stuck (%d->%d)!\n",
139 cpu, prev_nmi_count[cpu], get_nmi_count(cpu));
141 printk(KERN_WARNING
142 "Please report this to bugzilla.kernel.org,\n");
143 printk(KERN_WARNING
144 "and attach the output of the 'dmesg' command.\n");
146 nmi_usable = 0;
149 static void stop_watchdog(void *unused)
151 pcr_ops->write(PCR_PIC_PRIV);
154 static int __init check_nmi_watchdog(void)
156 unsigned int *prev_nmi_count;
157 int cpu, err;
159 prev_nmi_count = kmalloc(nr_cpu_ids * sizeof(unsigned int), GFP_KERNEL);
160 if (!prev_nmi_count) {
161 err = -ENOMEM;
162 goto error;
165 printk(KERN_INFO "Testing NMI watchdog ... ");
167 smp_call_function(nmi_cpu_busy, (void *)&endflag, 0);
169 for_each_possible_cpu(cpu)
170 prev_nmi_count[cpu] = get_nmi_count(cpu);
171 local_irq_enable();
172 mdelay((20 * 1000) / nmi_hz); /* wait 20 ticks */
174 for_each_online_cpu(cpu) {
175 if (get_nmi_count(cpu) - prev_nmi_count[cpu] <= 5)
176 report_broken_nmi(cpu, prev_nmi_count);
178 endflag = 1;
179 if (!nmi_usable) {
180 kfree(prev_nmi_count);
181 err = -ENODEV;
182 goto error;
184 printk("OK.\n");
186 nmi_hz = 1;
188 kfree(prev_nmi_count);
189 return 0;
190 error:
191 on_each_cpu(stop_watchdog, NULL, 1);
192 return err;
195 static void start_watchdog(void *unused)
197 pcr_ops->write(PCR_PIC_PRIV);
198 write_pic(picl_value(nmi_hz));
200 pcr_ops->write(pcr_enable);
203 void nmi_adjust_hz(unsigned int new_hz)
205 nmi_hz = new_hz;
206 on_each_cpu(start_watchdog, NULL, 1);
208 EXPORT_SYMBOL_GPL(nmi_adjust_hz);
210 static int nmi_shutdown(struct notifier_block *nb, unsigned long cmd, void *p)
212 on_each_cpu(stop_watchdog, NULL, 1);
213 return 0;
216 static struct notifier_block nmi_reboot_notifier = {
217 .notifier_call = nmi_shutdown,
220 int __init nmi_init(void)
222 int err;
224 nmi_usable = 1;
226 on_each_cpu(start_watchdog, NULL, 1);
228 err = check_nmi_watchdog();
229 if (!err) {
230 err = register_reboot_notifier(&nmi_reboot_notifier);
231 if (err) {
232 nmi_usable = 0;
233 on_each_cpu(stop_watchdog, NULL, 1);
236 return err;
239 static int __init setup_nmi_watchdog(char *str)
241 if (!strncmp(str, "panic", 5))
242 panic_on_timeout = 1;
244 return 0;
246 __setup("nmi_watchdog=", setup_nmi_watchdog);