Commit ee2eb3d4 authored by James Morse's avatar James Morse Committed by Rafael J. Wysocki
Browse files

ACPI / APEI: Generalise the estatus queue's notify code 



Refactor the estatus queue's pool notification routine from
NOTIFY_NMI's handlers. This will allow another notification
method to use the estatus queue without duplicating this code.

Add rcu_read_lock()/rcu_read_unlock() around the list
list_for_each_entry_rcu() walker. These aren't strictly necessary as
the whole nmi_enter/nmi_exit() window is a spooky RCU read-side
critical section.

in_nmi_queue_one_entry() is separate from the rcu-list walker for a
later caller that doesn't need to walk a list.

Signed-off-by: default avatarJames Morse <james.morse@arm.com>
Reviewed-by: default avatarPunit Agrawal <punit.agrawal@arm.com>
Tested-by: default avatarTyler Baicar <tbaicar@codeaurora.org>
[ rjw: Drop unnecessary err variable in two places ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 5cc6c682

drivers/acpi/apei/ghes.c

+41 −22
Original line number Diff line number Diff line
@@ -912,21 +912,14 @@ static void __process_error(struct ghes *ghes) 
#endif

}



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

static int ghes_in_nmi_queue_one_entry(struct ghes *ghes)

{

	u64 buf_paddr;

	struct ghes *ghes;

	int sev, ret = NMI_DONE;



	if (!atomic_add_unless(&ghes_in_nmi, 1, 1))

		return ret;

	int sev;



	list_for_each_entry_rcu(ghes, &ghes_nmi, list) {

	if (ghes_read_estatus(ghes, &buf_paddr)) {

		ghes_clear_estatus(ghes, buf_paddr);

			continue;

		} else {

			ret = NMI_HANDLED;

		return -ENOENT;

	}



	sev = ghes_severity(ghes->estatus->error_severity);
@@ -937,12 +930,38 @@ static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs) 


	__process_error(ghes);

	ghes_clear_estatus(ghes, buf_paddr);



	return 0;

}



#ifdef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG

	if (ret == NMI_HANDLED)

static int ghes_in_nmi_spool_from_list(struct list_head *rcu_list)

{

	int ret = -ENOENT;

	struct ghes *ghes;



	rcu_read_lock();

	list_for_each_entry_rcu(ghes, rcu_list, list) {

		if (!ghes_in_nmi_queue_one_entry(ghes))

			ret = 0;

	}

	rcu_read_unlock();



	if (IS_ENABLED(CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG) && !ret)

		irq_work_queue(&ghes_proc_irq_work);

#endif



	return ret;

}



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

{

	int ret = NMI_DONE;



	if (!atomic_add_unless(&ghes_in_nmi, 1, 1))

		return ret;



	if (!ghes_in_nmi_spool_from_list(&ghes_nmi))

		ret = NMI_HANDLED;



	atomic_dec(&ghes_in_nmi);

	return ret;

}

CRA Git | Maintained and supported by SUSTech CRA and CCSE