*
* Creates entries in /proc/sal for various system features.
*
- * Copyright (c) 2003 Silicon Graphics, Inc. All rights reserved.
+ * Copyright (c) 2003, 2006 Silicon Graphics, Inc. All rights reserved.
* Copyright (c) 2003 Hewlett-Packard Co
* Bjorn Helgaas <bjorn.helgaas@hp.com>
*
* mca.c may not pass a buffer, a NULL buffer just indicates that a new
* record is available in SAL.
* Replace some NR_CPUS by cpus_online, for hotplug cpu.
+ *
+ * Jan 5 2006 kaos@sgi.com
+ * Handle hotplug cpus coming online.
+ * Handle hotplug cpus going offline while they still have outstanding records.
+ * Use the cpu_* macros consistently.
+ * Replace the counting semaphore with a mutex and a test if the cpumask is non-empty.
+ * Modify the locking to make the test for "work to do" an atomic operation.
*/
#include <linux/capability.h>
+#include <linux/cpu.h>
#include <linux/types.h>
#include <linux/proc_fs.h>
#include <linux/module.h>
};
struct salinfo_data {
- volatile cpumask_t cpu_event; /* which cpus have outstanding events */
- struct semaphore sem; /* count of cpus with outstanding events (bits set in cpu_event) */
+ cpumask_t cpu_event; /* which cpus have outstanding events */
+ struct semaphore mutex;
u8 *log_buffer;
u64 log_size;
u8 *oemdata; /* decoded oem data */
int ret;
};
+/* Kick the mutex that tells user space that there is work to do. Instead of
+ * trying to track the state of the mutex across multiple cpus, in user
+ * context, interrupt context, non-maskable interrupt context and hotplug cpu,
+ * it is far easier just to grab the mutex if it is free then release it.
+ *
+ * This routine must be called with data_saved_lock held, to make the down/up
+ * operation atomic.
+ */
+static void
+salinfo_work_to_do(struct salinfo_data *data)
+{
+ down_trylock(&data->mutex);
+ up(&data->mutex);
+}
+
static void
salinfo_platform_oemdata_cpu(void *context)
{
BUG_ON(type >= ARRAY_SIZE(salinfo_log_name));
+ if (irqsafe)
+ spin_lock_irqsave(&data_saved_lock, flags);
if (buffer) {
- if (irqsafe)
- spin_lock_irqsave(&data_saved_lock, flags);
for (i = 0, data_saved = data->data_saved; i < saved_size; ++i, ++data_saved) {
if (!data_saved->buffer)
break;
data_saved->size = size;
data_saved->buffer = buffer;
}
- if (irqsafe)
- spin_unlock_irqrestore(&data_saved_lock, flags);
}
-
- if (!test_and_set_bit(smp_processor_id(), &data->cpu_event)) {
- if (irqsafe)
- up(&data->sem);
+ cpu_set(smp_processor_id(), data->cpu_event);
+ if (irqsafe) {
+ salinfo_work_to_do(data);
+ spin_unlock_irqrestore(&data_saved_lock, flags);
}
}
static void
salinfo_timeout_check(struct salinfo_data *data)
{
- int i;
+ unsigned long flags;
if (!data->open)
return;
- for_each_online_cpu(i) {
- if (test_bit(i, &data->cpu_event)) {
- /* double up() is not a problem, user space will see no
- * records for the additional "events".
- */
- up(&data->sem);
- }
+ if (!cpus_empty(data->cpu_event)) {
+ spin_lock_irqsave(&data_saved_lock, flags);
+ salinfo_work_to_do(data);
+ spin_unlock_irqrestore(&data_saved_lock, flags);
}
}
-static void
+static void
salinfo_timeout (unsigned long arg)
{
salinfo_timeout_check(salinfo_data + SAL_INFO_TYPE_MCA);
int i, n, cpu = -1;
retry:
- if (down_trylock(&data->sem)) {
+ if (cpus_empty(data->cpu_event) && down_trylock(&data->mutex)) {
if (file->f_flags & O_NONBLOCK)
return -EAGAIN;
- if (down_interruptible(&data->sem))
+ if (down_interruptible(&data->mutex))
return -EINTR;
}
n = data->cpu_check;
for (i = 0; i < NR_CPUS; i++) {
- if (test_bit(n, &data->cpu_event) && cpu_online(n)) {
+ if (cpu_isset(n, data->cpu_event)) {
+ if (!cpu_online(n)) {
+ cpu_clear(n, data->cpu_event);
+ continue;
+ }
cpu = n;
break;
}
if (cpu == -1)
goto retry;
- /* events are sticky until the user says "clear" */
- up(&data->sem);
-
/* for next read, start checking at next CPU */
data->cpu_check = cpu;
if (++data->cpu_check == NR_CPUS)
static void
call_on_cpu(int cpu, void (*fn)(void *), void *arg)
{
- cpumask_t save_cpus_allowed, new_cpus_allowed;
- memcpy(&save_cpus_allowed, ¤t->cpus_allowed, sizeof(save_cpus_allowed));
- memset(&new_cpus_allowed, 0, sizeof(new_cpus_allowed));
- set_bit(cpu, &new_cpus_allowed);
+ cpumask_t save_cpus_allowed = current->cpus_allowed;
+ cpumask_t new_cpus_allowed = cpumask_of_cpu(cpu);
set_cpus_allowed(current, new_cpus_allowed);
(*fn)(arg);
set_cpus_allowed(current, save_cpus_allowed);
if (!data->saved_num)
call_on_cpu(cpu, salinfo_log_read_cpu, data);
if (!data->log_size) {
- data->state = STATE_NO_DATA;
- clear_bit(cpu, &data->cpu_event);
+ data->state = STATE_NO_DATA;
+ cpu_clear(cpu, data->cpu_event);
} else {
- data->state = STATE_LOG_RECORD;
+ data->state = STATE_LOG_RECORD;
}
}
salinfo_log_clear(struct salinfo_data *data, int cpu)
{
sal_log_record_header_t *rh;
+ unsigned long flags;
+ spin_lock_irqsave(&data_saved_lock, flags);
data->state = STATE_NO_DATA;
- if (!test_bit(cpu, &data->cpu_event))
+ if (!cpu_isset(cpu, data->cpu_event)) {
+ spin_unlock_irqrestore(&data_saved_lock, flags);
return 0;
- down(&data->sem);
- clear_bit(cpu, &data->cpu_event);
+ }
+ cpu_clear(cpu, data->cpu_event);
if (data->saved_num) {
- unsigned long flags;
- spin_lock_irqsave(&data_saved_lock, flags);
- shift1_data_saved(data, data->saved_num - 1 );
+ shift1_data_saved(data, data->saved_num - 1);
data->saved_num = 0;
- spin_unlock_irqrestore(&data_saved_lock, flags);
}
+ spin_unlock_irqrestore(&data_saved_lock, flags);
rh = (sal_log_record_header_t *)(data->log_buffer);
/* Corrected errors have already been cleared from SAL */
if (rh->severity != sal_log_severity_corrected)
call_on_cpu(cpu, salinfo_log_clear_cpu, data);
/* clearing a record may make a new record visible */
salinfo_log_new_read(cpu, data);
- if (data->state == STATE_LOG_RECORD &&
- !test_and_set_bit(cpu, &data->cpu_event))
- up(&data->sem);
+ if (data->state == STATE_LOG_RECORD) {
+ spin_lock_irqsave(&data_saved_lock, flags);
+ cpu_set(cpu, data->cpu_event);
+ salinfo_work_to_do(data);
+ spin_unlock_irqrestore(&data_saved_lock, flags);
+ }
return 0;
}
.write = salinfo_log_write,
};
+#ifdef CONFIG_HOTPLUG_CPU
+static int __devinit
+salinfo_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu)
+{
+ unsigned int i, cpu = (unsigned long)hcpu;
+ unsigned long flags;
+ struct salinfo_data *data;
+ switch (action) {
+ case CPU_ONLINE:
+ spin_lock_irqsave(&data_saved_lock, flags);
+ for (i = 0, data = salinfo_data;
+ i < ARRAY_SIZE(salinfo_data);
+ ++i, ++data) {
+ cpu_set(cpu, data->cpu_event);
+ salinfo_work_to_do(data);
+ }
+ spin_unlock_irqrestore(&data_saved_lock, flags);
+ break;
+ case CPU_DEAD:
+ spin_lock_irqsave(&data_saved_lock, flags);
+ for (i = 0, data = salinfo_data;
+ i < ARRAY_SIZE(salinfo_data);
+ ++i, ++data) {
+ struct salinfo_data_saved *data_saved;
+ int j;
+ for (j = ARRAY_SIZE(data->data_saved) - 1, data_saved = data->data_saved + j;
+ j >= 0;
+ --j, --data_saved) {
+ if (data_saved->buffer && data_saved->cpu == cpu) {
+ shift1_data_saved(data, j);
+ }
+ }
+ cpu_clear(cpu, data->cpu_event);
+ }
+ spin_unlock_irqrestore(&data_saved_lock, flags);
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block salinfo_cpu_notifier =
+{
+ .notifier_call = salinfo_cpu_callback,
+ .priority = 0,
+};
+#endif /* CONFIG_HOTPLUG_CPU */
+
static int __init
salinfo_init(void)
{
struct proc_dir_entry **sdir = salinfo_proc_entries; /* keeps track of every entry */
struct proc_dir_entry *dir, *entry;
struct salinfo_data *data;
- int i, j, online;
+ int i, j;
salinfo_dir = proc_mkdir("sal", NULL);
if (!salinfo_dir)
for (i = 0; i < ARRAY_SIZE(salinfo_log_name); i++) {
data = salinfo_data + i;
data->type = i;
- sema_init(&data->sem, 0);
+ init_MUTEX(&data->mutex);
dir = proc_mkdir(salinfo_log_name[i], salinfo_dir);
if (!dir)
continue;
*sdir++ = entry;
/* we missed any events before now */
- online = 0;
- for_each_online_cpu(j) {
- set_bit(j, &data->cpu_event);
- ++online;
- }
- sema_init(&data->sem, online);
+ for_each_online_cpu(j)
+ cpu_set(j, data->cpu_event);
*sdir++ = dir;
}
salinfo_timer.function = &salinfo_timeout;
add_timer(&salinfo_timer);
+#ifdef CONFIG_HOTPLUG_CPU
+ register_cpu_notifier(&salinfo_cpu_notifier);
+#endif
+
return 0;
}
projects / linux-2.6 / commitdiff