Commit 4fc92254 authored by Jean-Philippe Brucker's avatar Jean-Philippe Brucker Committed by Will Deacon
Browse files

arm64: mm: Add asid_gen_match() helper 



Add a macro to check if an ASID is from the current generation, since a
subsequent patch will introduce a third user for this test.

Signed-off-by: default avatarJean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/r/20200519175502.2504091-6-jean-philippe@linaro.org


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent bd4298c7

arch/arm64/mm/context.c

+5 −3
Original line number Diff line number Diff line
@@ -92,6 +92,9 @@ static void set_reserved_asid_bits(void) 
		bitmap_clear(asid_map, 0, NUM_USER_ASIDS);

}



#define asid_gen_match(asid) \

	(!(((asid) ^ atomic64_read(&asid_generation)) >> asid_bits))



static void flush_context(void)

{

	int i;
@@ -220,8 +223,7 @@ void check_and_switch_context(struct mm_struct *mm, unsigned int cpu) 
	 *   because atomic RmWs are totally ordered for a given location.

	 */

	old_active_asid = atomic64_read(&per_cpu(active_asids, cpu));

	if (old_active_asid &&

	    !((asid ^ atomic64_read(&asid_generation)) >> asid_bits) &&

	if (old_active_asid && asid_gen_match(asid) &&

	    atomic64_cmpxchg_relaxed(&per_cpu(active_asids, cpu),

				     old_active_asid, asid))

		goto switch_mm_fastpath;
@@ -229,7 +231,7 @@ void check_and_switch_context(struct mm_struct *mm, unsigned int cpu) 
	raw_spin_lock_irqsave(&cpu_asid_lock, flags);

	/* Check that our ASID belongs to the current generation. */

	asid = atomic64_read(&mm->context.id);

	if ((asid ^ atomic64_read(&asid_generation)) >> asid_bits) {

	if (!asid_gen_match(asid)) {

		asid = new_context(mm);

		atomic64_set(&mm->context.id, asid);

	}

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