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e5553a6d DM |
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> | |
ffaba674 | 16 | #include <linux/reboot.h> |
e5553a6d DM |
17 | #include <linux/slab.h> |
18 | #include <linux/kdebug.h> | |
19 | #include <linux/delay.h> | |
20 | #include <linux/smp.h> | |
21 | ||
cdd6c482 | 22 | #include <asm/perf_event.h> |
e5553a6d DM |
23 | #include <asm/ptrace.h> |
24 | #include <asm/local.h> | |
25 | #include <asm/pcr.h> | |
26 | ||
27 | /* We don't have a real NMI on sparc64, but we can fake one | |
28 | * up using profiling counter overflow interrupts and interrupt | |
29 | * levels. | |
30 | * | |
31 | * The profile overflow interrupts at level 15, so we use | |
32 | * level 14 as our IRQ off level. | |
33 | */ | |
34 | ||
e5553a6d DM |
35 | static int panic_on_timeout; |
36 | ||
a8f22264 DM |
37 | /* nmi_active: |
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 | |
41 | */ | |
42 | atomic_t nmi_active = ATOMIC_INIT(0); /* oprofile uses this */ | |
43 | EXPORT_SYMBOL(nmi_active); | |
e5553a6d DM |
44 | |
45 | static unsigned int nmi_hz = HZ; | |
a8f22264 DM |
46 | static DEFINE_PER_CPU(short, wd_enabled); |
47 | static int endflag __initdata; | |
e5553a6d DM |
48 | |
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); | |
52 | ||
53 | void touch_nmi_watchdog(void) | |
54 | { | |
d89be56b | 55 | if (atomic_read(&nmi_active)) { |
e5553a6d DM |
56 | int cpu; |
57 | ||
58 | for_each_present_cpu(cpu) { | |
59 | if (per_cpu(nmi_touch, cpu) != 1) | |
60 | per_cpu(nmi_touch, cpu) = 1; | |
61 | } | |
62 | } | |
63 | ||
64 | touch_softlockup_watchdog(); | |
65 | } | |
66 | EXPORT_SYMBOL(touch_nmi_watchdog); | |
67 | ||
68 | static void die_nmi(const char *str, struct pt_regs *regs, int do_panic) | |
69 | { | |
70 | if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, | |
71 | pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP) | |
72 | return; | |
73 | ||
74 | console_verbose(); | |
75 | bust_spinlocks(1); | |
76 | ||
77 | printk(KERN_EMERG "%s", str); | |
78 | printk(" on CPU%d, ip %08lx, registers:\n", | |
79 | smp_processor_id(), regs->tpc); | |
80 | show_regs(regs); | |
dc4ff585 | 81 | dump_stack(); |
e5553a6d DM |
82 | |
83 | bust_spinlocks(0); | |
84 | ||
85 | if (do_panic || panic_on_oops) | |
86 | panic("Non maskable interrupt"); | |
87 | ||
2d0740c4 | 88 | nmi_exit(); |
e5553a6d DM |
89 | local_irq_enable(); |
90 | do_exit(SIGBUS); | |
91 | } | |
92 | ||
93 | notrace __kprobes void perfctr_irq(int irq, struct pt_regs *regs) | |
94 | { | |
95 | unsigned int sum, touched = 0; | |
96 | int cpu = smp_processor_id(); | |
97 | ||
98 | clear_softint(1 << irq); | |
99 | pcr_ops->write(PCR_PIC_PRIV); | |
100 | ||
101 | local_cpu_data().__nmi_count++; | |
102 | ||
2d0740c4 DM |
103 | nmi_enter(); |
104 | ||
e5553a6d DM |
105 | if (notify_die(DIE_NMI, "nmi", regs, 0, |
106 | pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP) | |
107 | touched = 1; | |
108 | ||
47a4a0e7 | 109 | sum = kstat_irqs_cpu(0, cpu); |
e5553a6d DM |
110 | if (__get_cpu_var(nmi_touch)) { |
111 | __get_cpu_var(nmi_touch) = 0; | |
112 | touched = 1; | |
113 | } | |
114 | if (!touched && __get_cpu_var(last_irq_sum) == sum) { | |
115 | local_inc(&__get_cpu_var(alert_counter)); | |
e6617c6e | 116 | if (local_read(&__get_cpu_var(alert_counter)) == 30 * nmi_hz) |
e5553a6d DM |
117 | die_nmi("BUG: NMI Watchdog detected LOCKUP", |
118 | regs, panic_on_timeout); | |
119 | } else { | |
120 | __get_cpu_var(last_irq_sum) = sum; | |
121 | local_set(&__get_cpu_var(alert_counter), 0); | |
122 | } | |
a8f22264 | 123 | if (__get_cpu_var(wd_enabled)) { |
e5553a6d DM |
124 | write_pic(picl_value(nmi_hz)); |
125 | pcr_ops->write(pcr_enable); | |
126 | } | |
2d0740c4 DM |
127 | |
128 | nmi_exit(); | |
e5553a6d DM |
129 | } |
130 | ||
131 | static inline unsigned int get_nmi_count(int cpu) | |
132 | { | |
133 | return cpu_data(cpu).__nmi_count; | |
134 | } | |
135 | ||
e5553a6d DM |
136 | static __init void nmi_cpu_busy(void *data) |
137 | { | |
138 | local_irq_enable_in_hardirq(); | |
139 | while (endflag == 0) | |
140 | mb(); | |
141 | } | |
142 | ||
143 | static void report_broken_nmi(int cpu, int *prev_nmi_count) | |
144 | { | |
145 | printk(KERN_CONT "\n"); | |
146 | ||
147 | printk(KERN_WARNING | |
148 | "WARNING: CPU#%d: NMI appears to be stuck (%d->%d)!\n", | |
149 | cpu, prev_nmi_count[cpu], get_nmi_count(cpu)); | |
150 | ||
151 | printk(KERN_WARNING | |
152 | "Please report this to bugzilla.kernel.org,\n"); | |
153 | printk(KERN_WARNING | |
154 | "and attach the output of the 'dmesg' command.\n"); | |
155 | ||
a8f22264 DM |
156 | per_cpu(wd_enabled, cpu) = 0; |
157 | atomic_dec(&nmi_active); | |
e5553a6d DM |
158 | } |
159 | ||
59abbd1e | 160 | void stop_nmi_watchdog(void *unused) |
e5553a6d DM |
161 | { |
162 | pcr_ops->write(PCR_PIC_PRIV); | |
a8f22264 DM |
163 | __get_cpu_var(wd_enabled) = 0; |
164 | atomic_dec(&nmi_active); | |
e5553a6d DM |
165 | } |
166 | ||
167 | static int __init check_nmi_watchdog(void) | |
168 | { | |
169 | unsigned int *prev_nmi_count; | |
170 | int cpu, err; | |
171 | ||
a8f22264 DM |
172 | if (!atomic_read(&nmi_active)) |
173 | return 0; | |
174 | ||
e5553a6d DM |
175 | prev_nmi_count = kmalloc(nr_cpu_ids * sizeof(unsigned int), GFP_KERNEL); |
176 | if (!prev_nmi_count) { | |
177 | err = -ENOMEM; | |
178 | goto error; | |
179 | } | |
180 | ||
181 | printk(KERN_INFO "Testing NMI watchdog ... "); | |
182 | ||
183 | smp_call_function(nmi_cpu_busy, (void *)&endflag, 0); | |
184 | ||
185 | for_each_possible_cpu(cpu) | |
186 | prev_nmi_count[cpu] = get_nmi_count(cpu); | |
187 | local_irq_enable(); | |
188 | mdelay((20 * 1000) / nmi_hz); /* wait 20 ticks */ | |
189 | ||
190 | for_each_online_cpu(cpu) { | |
a8f22264 DM |
191 | if (!per_cpu(wd_enabled, cpu)) |
192 | continue; | |
e5553a6d DM |
193 | if (get_nmi_count(cpu) - prev_nmi_count[cpu] <= 5) |
194 | report_broken_nmi(cpu, prev_nmi_count); | |
195 | } | |
196 | endflag = 1; | |
a8f22264 | 197 | if (!atomic_read(&nmi_active)) { |
e5553a6d | 198 | kfree(prev_nmi_count); |
a8f22264 | 199 | atomic_set(&nmi_active, -1); |
e5553a6d DM |
200 | err = -ENODEV; |
201 | goto error; | |
202 | } | |
203 | printk("OK.\n"); | |
204 | ||
205 | nmi_hz = 1; | |
206 | ||
207 | kfree(prev_nmi_count); | |
208 | return 0; | |
209 | error: | |
a8f22264 | 210 | on_each_cpu(stop_nmi_watchdog, NULL, 1); |
e5553a6d DM |
211 | return err; |
212 | } | |
213 | ||
59abbd1e | 214 | void start_nmi_watchdog(void *unused) |
a8f22264 DM |
215 | { |
216 | __get_cpu_var(wd_enabled) = 1; | |
217 | atomic_inc(&nmi_active); | |
218 | ||
219 | pcr_ops->write(PCR_PIC_PRIV); | |
220 | write_pic(picl_value(nmi_hz)); | |
221 | ||
222 | pcr_ops->write(pcr_enable); | |
223 | } | |
224 | ||
225 | static void nmi_adjust_hz_one(void *unused) | |
e5553a6d | 226 | { |
a8f22264 DM |
227 | if (!__get_cpu_var(wd_enabled)) |
228 | return; | |
229 | ||
e5553a6d DM |
230 | pcr_ops->write(PCR_PIC_PRIV); |
231 | write_pic(picl_value(nmi_hz)); | |
232 | ||
233 | pcr_ops->write(pcr_enable); | |
234 | } | |
235 | ||
236 | void nmi_adjust_hz(unsigned int new_hz) | |
237 | { | |
238 | nmi_hz = new_hz; | |
a8f22264 | 239 | on_each_cpu(nmi_adjust_hz_one, NULL, 1); |
e5553a6d DM |
240 | } |
241 | EXPORT_SYMBOL_GPL(nmi_adjust_hz); | |
242 | ||
ffaba674 DM |
243 | static int nmi_shutdown(struct notifier_block *nb, unsigned long cmd, void *p) |
244 | { | |
a8f22264 | 245 | on_each_cpu(stop_nmi_watchdog, NULL, 1); |
ffaba674 DM |
246 | return 0; |
247 | } | |
248 | ||
249 | static struct notifier_block nmi_reboot_notifier = { | |
250 | .notifier_call = nmi_shutdown, | |
251 | }; | |
252 | ||
e5553a6d DM |
253 | int __init nmi_init(void) |
254 | { | |
ffaba674 DM |
255 | int err; |
256 | ||
a8f22264 | 257 | on_each_cpu(start_nmi_watchdog, NULL, 1); |
e5553a6d | 258 | |
ffaba674 DM |
259 | err = check_nmi_watchdog(); |
260 | if (!err) { | |
261 | err = register_reboot_notifier(&nmi_reboot_notifier); | |
262 | if (err) { | |
a8f22264 DM |
263 | on_each_cpu(stop_nmi_watchdog, NULL, 1); |
264 | atomic_set(&nmi_active, -1); | |
ffaba674 DM |
265 | } |
266 | } | |
59abbd1e | 267 | if (!err) |
cdd6c482 | 268 | init_hw_perf_events(); |
59abbd1e | 269 | |
ffaba674 | 270 | return err; |
e5553a6d DM |
271 | } |
272 | ||
273 | static int __init setup_nmi_watchdog(char *str) | |
274 | { | |
275 | if (!strncmp(str, "panic", 5)) | |
276 | panic_on_timeout = 1; | |
277 | ||
278 | return 0; | |
279 | } | |
280 | __setup("nmi_watchdog=", setup_nmi_watchdog); |