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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 | ||
22 | #include <asm/ptrace.h> | |
23 | #include <asm/local.h> | |
24 | #include <asm/pcr.h> | |
25 | ||
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. | |
29 | * | |
30 | * The profile overflow interrupts at level 15, so we use | |
31 | * level 14 as our IRQ off level. | |
32 | */ | |
33 | ||
34 | static int nmi_watchdog_active; | |
35 | static int panic_on_timeout; | |
36 | ||
37 | int nmi_usable; | |
38 | EXPORT_SYMBOL_GPL(nmi_usable); | |
39 | ||
40 | static unsigned int nmi_hz = HZ; | |
41 | ||
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); | |
45 | ||
46 | void touch_nmi_watchdog(void) | |
47 | { | |
48 | if (nmi_watchdog_active) { | |
49 | int cpu; | |
50 | ||
51 | for_each_present_cpu(cpu) { | |
52 | if (per_cpu(nmi_touch, cpu) != 1) | |
53 | per_cpu(nmi_touch, cpu) = 1; | |
54 | } | |
55 | } | |
56 | ||
57 | touch_softlockup_watchdog(); | |
58 | } | |
59 | EXPORT_SYMBOL(touch_nmi_watchdog); | |
60 | ||
61 | static void die_nmi(const char *str, struct pt_regs *regs, int do_panic) | |
62 | { | |
63 | if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, | |
64 | pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP) | |
65 | return; | |
66 | ||
67 | console_verbose(); | |
68 | bust_spinlocks(1); | |
69 | ||
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); | |
dc4ff585 | 74 | dump_stack(); |
e5553a6d DM |
75 | |
76 | bust_spinlocks(0); | |
77 | ||
78 | if (do_panic || panic_on_oops) | |
79 | panic("Non maskable interrupt"); | |
80 | ||
81 | local_irq_enable(); | |
82 | do_exit(SIGBUS); | |
83 | } | |
84 | ||
85 | notrace __kprobes void perfctr_irq(int irq, struct pt_regs *regs) | |
86 | { | |
87 | unsigned int sum, touched = 0; | |
88 | int cpu = smp_processor_id(); | |
89 | ||
90 | clear_softint(1 << irq); | |
91 | pcr_ops->write(PCR_PIC_PRIV); | |
92 | ||
93 | local_cpu_data().__nmi_count++; | |
94 | ||
95 | if (notify_die(DIE_NMI, "nmi", regs, 0, | |
96 | pt_regs_trap_type(regs), SIGINT) == NOTIFY_STOP) | |
97 | touched = 1; | |
98 | ||
47a4a0e7 | 99 | sum = kstat_irqs_cpu(0, cpu); |
e5553a6d DM |
100 | if (__get_cpu_var(nmi_touch)) { |
101 | __get_cpu_var(nmi_touch) = 0; | |
102 | touched = 1; | |
103 | } | |
104 | if (!touched && __get_cpu_var(last_irq_sum) == sum) { | |
105 | local_inc(&__get_cpu_var(alert_counter)); | |
e6617c6e | 106 | if (local_read(&__get_cpu_var(alert_counter)) == 30 * nmi_hz) |
e5553a6d DM |
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); | |
112 | } | |
113 | if (nmi_usable) { | |
114 | write_pic(picl_value(nmi_hz)); | |
115 | pcr_ops->write(pcr_enable); | |
116 | } | |
117 | } | |
118 | ||
119 | static inline unsigned int get_nmi_count(int cpu) | |
120 | { | |
121 | return cpu_data(cpu).__nmi_count; | |
122 | } | |
123 | ||
124 | static int endflag __initdata; | |
125 | ||
126 | static __init void nmi_cpu_busy(void *data) | |
127 | { | |
128 | local_irq_enable_in_hardirq(); | |
129 | while (endflag == 0) | |
130 | mb(); | |
131 | } | |
132 | ||
133 | static void report_broken_nmi(int cpu, int *prev_nmi_count) | |
134 | { | |
135 | printk(KERN_CONT "\n"); | |
136 | ||
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)); | |
140 | ||
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"); | |
145 | ||
146 | nmi_usable = 0; | |
147 | } | |
148 | ||
149 | static void stop_watchdog(void *unused) | |
150 | { | |
151 | pcr_ops->write(PCR_PIC_PRIV); | |
152 | } | |
153 | ||
154 | static int __init check_nmi_watchdog(void) | |
155 | { | |
156 | unsigned int *prev_nmi_count; | |
157 | int cpu, err; | |
158 | ||
159 | prev_nmi_count = kmalloc(nr_cpu_ids * sizeof(unsigned int), GFP_KERNEL); | |
160 | if (!prev_nmi_count) { | |
161 | err = -ENOMEM; | |
162 | goto error; | |
163 | } | |
164 | ||
165 | printk(KERN_INFO "Testing NMI watchdog ... "); | |
166 | ||
167 | smp_call_function(nmi_cpu_busy, (void *)&endflag, 0); | |
168 | ||
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 */ | |
173 | ||
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); | |
177 | } | |
178 | endflag = 1; | |
179 | if (!nmi_usable) { | |
180 | kfree(prev_nmi_count); | |
181 | err = -ENODEV; | |
182 | goto error; | |
183 | } | |
184 | printk("OK.\n"); | |
185 | ||
186 | nmi_hz = 1; | |
187 | ||
188 | kfree(prev_nmi_count); | |
189 | return 0; | |
190 | error: | |
191 | on_each_cpu(stop_watchdog, NULL, 1); | |
192 | return err; | |
193 | } | |
194 | ||
195 | static void start_watchdog(void *unused) | |
196 | { | |
197 | pcr_ops->write(PCR_PIC_PRIV); | |
198 | write_pic(picl_value(nmi_hz)); | |
199 | ||
200 | pcr_ops->write(pcr_enable); | |
201 | } | |
202 | ||
203 | void nmi_adjust_hz(unsigned int new_hz) | |
204 | { | |
205 | nmi_hz = new_hz; | |
206 | on_each_cpu(start_watchdog, NULL, 1); | |
207 | } | |
208 | EXPORT_SYMBOL_GPL(nmi_adjust_hz); | |
209 | ||
ffaba674 DM |
210 | static int nmi_shutdown(struct notifier_block *nb, unsigned long cmd, void *p) |
211 | { | |
212 | on_each_cpu(stop_watchdog, NULL, 1); | |
213 | return 0; | |
214 | } | |
215 | ||
216 | static struct notifier_block nmi_reboot_notifier = { | |
217 | .notifier_call = nmi_shutdown, | |
218 | }; | |
219 | ||
e5553a6d DM |
220 | int __init nmi_init(void) |
221 | { | |
ffaba674 DM |
222 | int err; |
223 | ||
e5553a6d DM |
224 | nmi_usable = 1; |
225 | ||
226 | on_each_cpu(start_watchdog, NULL, 1); | |
227 | ||
ffaba674 DM |
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); | |
234 | } | |
235 | } | |
236 | return err; | |
e5553a6d DM |
237 | } |
238 | ||
239 | static int __init setup_nmi_watchdog(char *str) | |
240 | { | |
241 | if (!strncmp(str, "panic", 5)) | |
242 | panic_on_timeout = 1; | |
243 | ||
244 | return 0; | |
245 | } | |
246 | __setup("nmi_watchdog=", setup_nmi_watchdog); |