Commit 169c018d authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Will Deacon

arm64: don't flag non-aliasing VIPT I-caches as aliasing

VIPT caches are non-aliasing if the index is derived from address bits that
are always equal between VA and PA. Classifying these as aliasing results in
unnecessary flushing which may hurt performance.
Signed-off-by: default avatarArd Biesheuvel <>
Acked-by: default avatarWill Deacon <>
Signed-off-by: default avatarWill Deacon <>
parent 80c517b0
......@@ -49,8 +49,18 @@ static void cpuinfo_detect_icache_policy(struct cpuinfo_arm64 *info)
unsigned int cpu = smp_processor_id();
u32 l1ip = CTR_L1IP(info->reg_ctr);
set_bit(ICACHEF_ALIASING, &__icache_flags);
if (l1ip != ICACHE_POLICY_PIPT) {
* VIPT caches are non-aliasing if the VA always equals the PA
* in all bit positions that are covered by the index. This is
* the case if the size of a way (# of sets * line size) does
* not exceed PAGE_SIZE.
u32 waysize = icache_get_numsets() * icache_get_linesize();
if (l1ip != ICACHE_POLICY_VIPT || waysize > PAGE_SIZE)
set_bit(ICACHEF_ALIASING, &__icache_flags);
set_bit(ICACHEF_AIVIVT, &__icache_flags);
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