Commit 9c9d0805 authored by James Morse's avatar James Morse Committed by Rafael J. Wysocki
Browse files

ACPI / APEI: Move NOTIFY_SEA between the estatus-queue and NOTIFY_NMI 



The estatus-queue code is currently hidden by the NOTIFY_NMI #ifdefs.
Once NOTIFY_SEA starts using the estatus-queue we can stop hiding
it as each architecture has a user that can't be turned off.

Split the existing CONFIG_HAVE_ACPI_APEI_NMI block in two, and move
the SEA code into the gap.

Move the code around ... and changes the stale comment describing
why the status queue is necessary: printk() is no longer the issue,
its the helpers like memory_failure_queue() that aren't nmi safe.

Signed-off-by: default avatarJames Morse <james.morse@arm.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 06ddeadc

drivers/acpi/apei/ghes.c

+59 −54
Original line number Diff line number Diff line
@@ -767,66 +767,21 @@ static struct notifier_block ghes_notifier_hed = { 
	.notifier_call = ghes_notify_hed,

};



#ifdef CONFIG_ACPI_APEI_SEA

static LIST_HEAD(ghes_sea);



/*

 * Return 0 only if one of the SEA error sources successfully reported an error

 * record sent from the firmware.

 */

int ghes_notify_sea(void)

{

	struct ghes *ghes;

	int ret = -ENOENT;



	rcu_read_lock();

	list_for_each_entry_rcu(ghes, &ghes_sea, list) {

		if (!ghes_proc(ghes))

			ret = 0;

	}

	rcu_read_unlock();

	return ret;

}



static void ghes_sea_add(struct ghes *ghes)

{

	mutex_lock(&ghes_list_mutex);

	list_add_rcu(&ghes->list, &ghes_sea);

	mutex_unlock(&ghes_list_mutex);

}



static void ghes_sea_remove(struct ghes *ghes)

{

	mutex_lock(&ghes_list_mutex);

	list_del_rcu(&ghes->list);

	mutex_unlock(&ghes_list_mutex);

	synchronize_rcu();

}

#else /* CONFIG_ACPI_APEI_SEA */

static inline void ghes_sea_add(struct ghes *ghes) { }

static inline void ghes_sea_remove(struct ghes *ghes) { }

#endif /* CONFIG_ACPI_APEI_SEA */



#ifdef CONFIG_HAVE_ACPI_APEI_NMI

/*

 * printk is not safe in NMI context.  So in NMI handler, we allocate

 * required memory from lock-less memory allocator

 * (ghes_estatus_pool), save estatus into it, put them into lock-less

 * list (ghes_estatus_llist), then delay printk into IRQ context via

 * irq_work (ghes_proc_irq_work).  ghes_estatus_size_request record

 * required pool size by all NMI error source.

 * Handlers for CPER records may not be NMI safe. For example,

 * memory_failure_queue() takes spinlocks and calls schedule_work_on().

 * In any NMI-like handler, memory from ghes_estatus_pool is used to save

 * estatus, and added to the ghes_estatus_llist. irq_work_queue() causes

 * ghes_proc_in_irq() to run in IRQ context where each estatus in

 * ghes_estatus_llist is processed.

 *

 * Memory from the ghes_estatus_pool is also used with the ghes_estatus_cache

 * to suppress frequent messages.

 */

static struct llist_head ghes_estatus_llist;

static struct irq_work ghes_proc_irq_work;



/*

 * NMI may be triggered on any CPU, so ghes_in_nmi is used for

 * having only one concurrent reader.

 */

static atomic_t ghes_in_nmi = ATOMIC_INIT(0);



static LIST_HEAD(ghes_nmi);



static void ghes_proc_in_irq(struct irq_work *irq_work)

{

	struct llist_node *llnode, *next;
@@ -948,6 +903,56 @@ static int ghes_in_nmi_spool_from_list(struct list_head *rcu_list) 


	return ret;

}

#endif /* CONFIG_HAVE_ACPI_APEI_NMI */



#ifdef CONFIG_ACPI_APEI_SEA

static LIST_HEAD(ghes_sea);



/*

 * Return 0 only if one of the SEA error sources successfully reported an error

 * record sent from the firmware.

 */

int ghes_notify_sea(void)

{

	struct ghes *ghes;

	int ret = -ENOENT;



	rcu_read_lock();

	list_for_each_entry_rcu(ghes, &ghes_sea, list) {

		if (!ghes_proc(ghes))

			ret = 0;

	}

	rcu_read_unlock();

	return ret;

}



static void ghes_sea_add(struct ghes *ghes)

{

	mutex_lock(&ghes_list_mutex);

	list_add_rcu(&ghes->list, &ghes_sea);

	mutex_unlock(&ghes_list_mutex);

}



static void ghes_sea_remove(struct ghes *ghes)

{

	mutex_lock(&ghes_list_mutex);

	list_del_rcu(&ghes->list);

	mutex_unlock(&ghes_list_mutex);

	synchronize_rcu();

}

#else /* CONFIG_ACPI_APEI_SEA */

static inline void ghes_sea_add(struct ghes *ghes) { }

static inline void ghes_sea_remove(struct ghes *ghes) { }

#endif /* CONFIG_ACPI_APEI_SEA */



#ifdef CONFIG_HAVE_ACPI_APEI_NMI

/*

 * NMI may be triggered on any CPU, so ghes_in_nmi is used for

 * having only one concurrent reader.

 */

static atomic_t ghes_in_nmi = ATOMIC_INIT(0);



static LIST_HEAD(ghes_nmi);



static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)

{

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