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authorDavid S. Miller <davem@davemloft.net>2009-09-09 08:16:06 +0200
committerDavid S. Miller <davem@davemloft.net>2009-09-09 08:16:06 +0200
commita8f22264550e64c0cd11fb6647284b0bd6407f9c (patch)
treee42ef7f04063bef6114c6488c70eff7089b5ea26
parentsparc: add basic support for 'perf' (diff)
downloadlinux-a8f22264550e64c0cd11fb6647284b0bd6407f9c.tar.xz
linux-a8f22264550e64c0cd11fb6647284b0bd6407f9c.zip
sparc64: Manage NMI watchdog enabling like x86.
Use a per-cpu 'wd_enabled' boolean and a global atomic_t count of watchdog NMI enabled cpus which is set to '-1' if something is wrong with the watchdog and it can't be used. Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--arch/sparc/include/asm/nmi.h2
-rw-r--r--arch/sparc/kernel/nmi.c60
-rw-r--r--arch/sparc/oprofile/init.c2
3 files changed, 45 insertions, 19 deletions
diff --git a/arch/sparc/include/asm/nmi.h b/arch/sparc/include/asm/nmi.h
index fbd546dd4feb..c7d11e435df9 100644
--- a/arch/sparc/include/asm/nmi.h
+++ b/arch/sparc/include/asm/nmi.h
@@ -5,6 +5,6 @@ extern int __init nmi_init(void);
extern void perfctr_irq(int irq, struct pt_regs *regs);
extern void nmi_adjust_hz(unsigned int new_hz);
-extern int nmi_usable;
+extern atomic_t nmi_active;
#endif /* __NMI_H */
diff --git a/arch/sparc/kernel/nmi.c b/arch/sparc/kernel/nmi.c
index 2c0cc72d295b..d1614e8384ae 100644
--- a/arch/sparc/kernel/nmi.c
+++ b/arch/sparc/kernel/nmi.c
@@ -34,10 +34,17 @@
static int nmi_watchdog_active;
static int panic_on_timeout;
-int nmi_usable;
-EXPORT_SYMBOL_GPL(nmi_usable);
+/* nmi_active:
+ * >0: the NMI watchdog is active, but can be disabled
+ * <0: the NMI watchdog has not been set up, and cannot be enabled
+ * 0: the NMI watchdog is disabled, but can be enabled
+ */
+atomic_t nmi_active = ATOMIC_INIT(0); /* oprofile uses this */
+EXPORT_SYMBOL(nmi_active);
static unsigned int nmi_hz = HZ;
+static DEFINE_PER_CPU(short, wd_enabled);
+static int endflag __initdata;
static DEFINE_PER_CPU(unsigned int, last_irq_sum);
static DEFINE_PER_CPU(local_t, alert_counter);
@@ -110,7 +117,7 @@ notrace __kprobes void perfctr_irq(int irq, struct pt_regs *regs)
__get_cpu_var(last_irq_sum) = sum;
local_set(&__get_cpu_var(alert_counter), 0);
}
- if (nmi_usable) {
+ if (__get_cpu_var(wd_enabled)) {
write_pic(picl_value(nmi_hz));
pcr_ops->write(pcr_enable);
}
@@ -121,8 +128,6 @@ static inline unsigned int get_nmi_count(int cpu)
return cpu_data(cpu).__nmi_count;
}
-static int endflag __initdata;
-
static __init void nmi_cpu_busy(void *data)
{
local_irq_enable_in_hardirq();
@@ -143,12 +148,15 @@ static void report_broken_nmi(int cpu, int *prev_nmi_count)
printk(KERN_WARNING
"and attach the output of the 'dmesg' command.\n");
- nmi_usable = 0;
+ per_cpu(wd_enabled, cpu) = 0;
+ atomic_dec(&nmi_active);
}
-static void stop_watchdog(void *unused)
+static void stop_nmi_watchdog(void *unused)
{
pcr_ops->write(PCR_PIC_PRIV);
+ __get_cpu_var(wd_enabled) = 0;
+ atomic_dec(&nmi_active);
}
static int __init check_nmi_watchdog(void)
@@ -156,6 +164,9 @@ static int __init check_nmi_watchdog(void)
unsigned int *prev_nmi_count;
int cpu, err;
+ if (!atomic_read(&nmi_active))
+ return 0;
+
prev_nmi_count = kmalloc(nr_cpu_ids * sizeof(unsigned int), GFP_KERNEL);
if (!prev_nmi_count) {
err = -ENOMEM;
@@ -172,12 +183,15 @@ static int __init check_nmi_watchdog(void)
mdelay((20 * 1000) / nmi_hz); /* wait 20 ticks */
for_each_online_cpu(cpu) {
+ if (!per_cpu(wd_enabled, cpu))
+ continue;
if (get_nmi_count(cpu) - prev_nmi_count[cpu] <= 5)
report_broken_nmi(cpu, prev_nmi_count);
}
endflag = 1;
- if (!nmi_usable) {
+ if (!atomic_read(&nmi_active)) {
kfree(prev_nmi_count);
+ atomic_set(&nmi_active, -1);
err = -ENODEV;
goto error;
}
@@ -188,12 +202,26 @@ static int __init check_nmi_watchdog(void)
kfree(prev_nmi_count);
return 0;
error:
- on_each_cpu(stop_watchdog, NULL, 1);
+ on_each_cpu(stop_nmi_watchdog, NULL, 1);
return err;
}
-static void start_watchdog(void *unused)
+static void start_nmi_watchdog(void *unused)
+{
+ __get_cpu_var(wd_enabled) = 1;
+ atomic_inc(&nmi_active);
+
+ pcr_ops->write(PCR_PIC_PRIV);
+ write_pic(picl_value(nmi_hz));
+
+ pcr_ops->write(pcr_enable);
+}
+
+static void nmi_adjust_hz_one(void *unused)
{
+ if (!__get_cpu_var(wd_enabled))
+ return;
+
pcr_ops->write(PCR_PIC_PRIV);
write_pic(picl_value(nmi_hz));
@@ -203,13 +231,13 @@ static void start_watchdog(void *unused)
void nmi_adjust_hz(unsigned int new_hz)
{
nmi_hz = new_hz;
- on_each_cpu(start_watchdog, NULL, 1);
+ on_each_cpu(nmi_adjust_hz_one, NULL, 1);
}
EXPORT_SYMBOL_GPL(nmi_adjust_hz);
static int nmi_shutdown(struct notifier_block *nb, unsigned long cmd, void *p)
{
- on_each_cpu(stop_watchdog, NULL, 1);
+ on_each_cpu(stop_nmi_watchdog, NULL, 1);
return 0;
}
@@ -221,16 +249,14 @@ int __init nmi_init(void)
{
int err;
- nmi_usable = 1;
-
- on_each_cpu(start_watchdog, NULL, 1);
+ on_each_cpu(start_nmi_watchdog, NULL, 1);
err = check_nmi_watchdog();
if (!err) {
err = register_reboot_notifier(&nmi_reboot_notifier);
if (err) {
- nmi_usable = 0;
- on_each_cpu(stop_watchdog, NULL, 1);
+ on_each_cpu(stop_nmi_watchdog, NULL, 1);
+ atomic_set(&nmi_active, -1);
}
}
return err;
diff --git a/arch/sparc/oprofile/init.c b/arch/sparc/oprofile/init.c
index d172f86439b1..9ce34fd294c9 100644
--- a/arch/sparc/oprofile/init.c
+++ b/arch/sparc/oprofile/init.c
@@ -57,7 +57,7 @@ static void timer_stop(void)
static int op_nmi_timer_init(struct oprofile_operations *ops)
{
- if (!nmi_usable)
+ if (atomic_read(&nmi_active) <= 0)
return -ENODEV;
ops->start = timer_start;