Commit 8b08e840 authored by Dave Martin's avatar Dave Martin Committed by Marc Zyngier
Browse files

arm64/sve: Clarify role of the VQ map maintenance functions 



The roles of sve_init_vq_map(), sve_update_vq_map() and
sve_verify_vq_map() are highly non-obvious to anyone who has not dug
through cpufeatures.c in detail.

Since the way these functions interact with each other is more
important here than a full understanding of the cpufeatures code, this
patch adds comments to make the functions' roles clearer.

No functional change.

Signed-off-by: default avatarDave Martin <Dave.Martin@arm.com>
Reviewed-by: default avatarJulien Thierry <julien.thierry@arm.com>
Reviewed-by: default avatarJulien Grall <julien.grall@arm.com>
Tested-by: default avatarzhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 3f61f409

arch/arm64/kernel/fpsimd.c

+9 −1
Original line number Diff line number Diff line
@@ -647,6 +647,10 @@ static void sve_probe_vqs(DECLARE_BITMAP(map, SVE_VQ_MAX)) 
	}

}



/*

 * Initialise the set of known supported VQs for the boot CPU.

 * This is called during kernel boot, before secondary CPUs are brought up.

 */

void __init sve_init_vq_map(void)

{

	sve_probe_vqs(sve_vq_map);
@@ -655,6 +659,7 @@ void __init sve_init_vq_map(void) 
/*

 * If we haven't committed to the set of supported VQs yet, filter out

 * those not supported by the current CPU.

 * This function is called during the bring-up of early secondary CPUs only.

 */

void sve_update_vq_map(void)

{
@@ -662,7 +667,10 @@ void sve_update_vq_map(void) 
	bitmap_and(sve_vq_map, sve_vq_map, sve_secondary_vq_map, SVE_VQ_MAX);

}



/* Check whether the current CPU supports all VQs in the committed set */

/*

 * Check whether the current CPU supports all VQs in the committed set.

 * This function is called during the bring-up of late secondary CPUs only.

 */

int sve_verify_vq_map(void)

{

	int ret = 0;