x86: Set cpu masks before calling CPU_STARTING notifiers
[linux-2.6.git] / arch / sparc / kernel / nmi.c
1 /* Pseudo NMI support on sparc64 systems.
2  *
3  * Copyright (C) 2009 David S. Miller <davem@davemloft.net>
4  *
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>
21
22 #include <asm/perf_event.h>
23 #include <asm/ptrace.h>
24 #include <asm/pcr.h>
25
26 #include "kstack.h"
27
28 /* We don't have a real NMI on sparc64, but we can fake one
29  * up using profiling counter overflow interrupts and interrupt
30  * levels.
31  *
32  * The profile overflow interrupts at level 15, so we use
33  * level 14 as our IRQ off level.
34  */
35
36 static int panic_on_timeout;
37
38 /* nmi_active:
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
42  */
43 atomic_t nmi_active = ATOMIC_INIT(0);           /* oprofile uses this */
44 EXPORT_SYMBOL(nmi_active);
45
46 static unsigned int nmi_hz = HZ;
47 static DEFINE_PER_CPU(short, wd_enabled);
48 static int endflag __initdata;
49
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);
53
54 void touch_nmi_watchdog(void)
55 {
56         if (atomic_read(&nmi_active)) {
57                 int cpu;
58
59                 for_each_present_cpu(cpu) {
60                         if (per_cpu(nmi_touch, cpu) != 1)
61                                 per_cpu(nmi_touch, cpu) = 1;
62                 }
63         }
64
65         touch_softlockup_watchdog();
66 }
67 EXPORT_SYMBOL(touch_nmi_watchdog);
68
69 static void die_nmi(const char *str, struct pt_regs *regs, int do_panic)
70 {
71         if (notify_die(DIE_NMIWATCHDOG, str, regs, 0,
72                        pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP)
73                 return;
74
75         console_verbose();
76         bust_spinlocks(1);
77
78         printk(KERN_EMERG "%s", str);
79         printk(" on CPU%d, ip %08lx, registers:\n",
80                smp_processor_id(), regs->tpc);
81         show_regs(regs);
82         dump_stack();
83
84         bust_spinlocks(0);
85
86         if (do_panic || panic_on_oops)
87                 panic("Non maskable interrupt");
88
89         nmi_exit();
90         local_irq_enable();
91         do_exit(SIGBUS);
92 }
93
94 notrace __kprobes void perfctr_irq(int irq, struct pt_regs *regs)
95 {
96         unsigned int sum, touched = 0;
97         void *orig_sp;
98
99         clear_softint(1 << irq);
100
101         local_cpu_data().__nmi_count++;
102
103         nmi_enter();
104
105         orig_sp = set_hardirq_stack();
106
107         if (notify_die(DIE_NMI, "nmi", regs, 0,
108                        pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP)
109                 touched = 1;
110         else
111                 pcr_ops->write(PCR_PIC_PRIV);
112
113         sum = local_cpu_data().irq0_irqs;
114         if (__get_cpu_var(nmi_touch)) {
115                 __get_cpu_var(nmi_touch) = 0;
116                 touched = 1;
117         }
118         if (!touched && __get_cpu_var(last_irq_sum) == sum) {
119                 __this_cpu_inc(alert_counter);
120                 if (__this_cpu_read(alert_counter) == 30 * nmi_hz)
121                         die_nmi("BUG: NMI Watchdog detected LOCKUP",
122                                 regs, panic_on_timeout);
123         } else {
124                 __get_cpu_var(last_irq_sum) = sum;
125                 __this_cpu_write(alert_counter, 0);
126         }
127         if (__get_cpu_var(wd_enabled)) {
128                 write_pic(picl_value(nmi_hz));
129                 pcr_ops->write(pcr_enable);
130         }
131
132         restore_hardirq_stack(orig_sp);
133
134         nmi_exit();
135 }
136
137 static inline unsigned int get_nmi_count(int cpu)
138 {
139         return cpu_data(cpu).__nmi_count;
140 }
141
142 static __init void nmi_cpu_busy(void *data)
143 {
144         local_irq_enable_in_hardirq();
145         while (endflag == 0)
146                 mb();
147 }
148
149 static void report_broken_nmi(int cpu, int *prev_nmi_count)
150 {
151         printk(KERN_CONT "\n");
152
153         printk(KERN_WARNING
154                 "WARNING: CPU#%d: NMI appears to be stuck (%d->%d)!\n",
155                         cpu, prev_nmi_count[cpu], get_nmi_count(cpu));
156
157         printk(KERN_WARNING
158                 "Please report this to bugzilla.kernel.org,\n");
159         printk(KERN_WARNING
160                 "and attach the output of the 'dmesg' command.\n");
161
162         per_cpu(wd_enabled, cpu) = 0;
163         atomic_dec(&nmi_active);
164 }
165
166 void stop_nmi_watchdog(void *unused)
167 {
168         pcr_ops->write(PCR_PIC_PRIV);
169         __get_cpu_var(wd_enabled) = 0;
170         atomic_dec(&nmi_active);
171 }
172
173 static int __init check_nmi_watchdog(void)
174 {
175         unsigned int *prev_nmi_count;
176         int cpu, err;
177
178         if (!atomic_read(&nmi_active))
179                 return 0;
180
181         prev_nmi_count = kmalloc(nr_cpu_ids * sizeof(unsigned int), GFP_KERNEL);
182         if (!prev_nmi_count) {
183                 err = -ENOMEM;
184                 goto error;
185         }
186
187         printk(KERN_INFO "Testing NMI watchdog ... ");
188
189         smp_call_function(nmi_cpu_busy, (void *)&endflag, 0);
190
191         for_each_possible_cpu(cpu)
192                 prev_nmi_count[cpu] = get_nmi_count(cpu);
193         local_irq_enable();
194         mdelay((20 * 1000) / nmi_hz); /* wait 20 ticks */
195
196         for_each_online_cpu(cpu) {
197                 if (!per_cpu(wd_enabled, cpu))
198                         continue;
199                 if (get_nmi_count(cpu) - prev_nmi_count[cpu] <= 5)
200                         report_broken_nmi(cpu, prev_nmi_count);
201         }
202         endflag = 1;
203         if (!atomic_read(&nmi_active)) {
204                 kfree(prev_nmi_count);
205                 atomic_set(&nmi_active, -1);
206                 err = -ENODEV;
207                 goto error;
208         }
209         printk("OK.\n");
210
211         nmi_hz = 1;
212
213         kfree(prev_nmi_count);
214         return 0;
215 error:
216         on_each_cpu(stop_nmi_watchdog, NULL, 1);
217         return err;
218 }
219
220 void start_nmi_watchdog(void *unused)
221 {
222         __get_cpu_var(wd_enabled) = 1;
223         atomic_inc(&nmi_active);
224
225         pcr_ops->write(PCR_PIC_PRIV);
226         write_pic(picl_value(nmi_hz));
227
228         pcr_ops->write(pcr_enable);
229 }
230
231 static void nmi_adjust_hz_one(void *unused)
232 {
233         if (!__get_cpu_var(wd_enabled))
234                 return;
235
236         pcr_ops->write(PCR_PIC_PRIV);
237         write_pic(picl_value(nmi_hz));
238
239         pcr_ops->write(pcr_enable);
240 }
241
242 void nmi_adjust_hz(unsigned int new_hz)
243 {
244         nmi_hz = new_hz;
245         on_each_cpu(nmi_adjust_hz_one, NULL, 1);
246 }
247 EXPORT_SYMBOL_GPL(nmi_adjust_hz);
248
249 static int nmi_shutdown(struct notifier_block *nb, unsigned long cmd, void *p)
250 {
251         on_each_cpu(stop_nmi_watchdog, NULL, 1);
252         return 0;
253 }
254
255 static struct notifier_block nmi_reboot_notifier = {
256         .notifier_call = nmi_shutdown,
257 };
258
259 int __init nmi_init(void)
260 {
261         int err;
262
263         on_each_cpu(start_nmi_watchdog, NULL, 1);
264
265         err = check_nmi_watchdog();
266         if (!err) {
267                 err = register_reboot_notifier(&nmi_reboot_notifier);
268                 if (err) {
269                         on_each_cpu(stop_nmi_watchdog, NULL, 1);
270                         atomic_set(&nmi_active, -1);
271                 }
272         }
273         if (!err)
274                 init_hw_perf_events();
275
276         return err;
277 }
278
279 static int __init setup_nmi_watchdog(char *str)
280 {
281         if (!strncmp(str, "panic", 5))
282                 panic_on_timeout = 1;
283
284         return 0;
285 }
286 __setup("nmi_watchdog=", setup_nmi_watchdog);