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| author | Jean-Philippe Brucker <jean-philippe@linaro.org> | 2020-05-19 20:54:43 +0300 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-05-21 16:46:14 +0300 |
| commit | 4fc92254bf86b19ac1ef81f61f4e690fccfcba4a (patch) | |
| tree | c6c5b8fdf827eda90471d6bc1a1eed4e35c78177 /arch/arm64/mm | |
| parent | bd4298c72b56d7faf0ee3671739f3a704a962d0f (diff) | |
| download | linux-4fc92254bf86b19ac1ef81f61f4e690fccfcba4a.tar.xz | |
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: Jean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/r/20200519175502.2504091-6-jean-philippe@linaro.org
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/mm')
| -rw-r--r-- | arch/arm64/mm/context.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c index 9b26f9a88724..d702d60e64da 100644 --- a/arch/arm64/mm/context.c +++ b/arch/arm64/mm/context.c @@ -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); } |