diff options
| author |   Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2014-08-08 12:51:40 +0100 |
|---|---|---|
| committer |   Will Deacon <will.deacon@arm.com> | 2014-09-08 14:39:18 +0100 |
| commit | 169c018de7b6d376f821f9fae0ab23dc5c7bb549 (patch) | |
| tree | 8c008b183e64a8512268405fb8fd85a74a26b932 /arch/arm64/kernel/cpuinfo.c | |
| parent | arm64: add helper functions to read I-cache attributes (diff) | |
| download | linux-dev-169c018de7b6d376f821f9fae0ab23dc5c7bb549.tar.xz linux-dev-169c018de7b6d376f821f9fae0ab23dc5c7bb549.zip | |
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: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to '')
| -rw-r--r-- | arch/arm64/kernel/cpuinfo.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c index d8c5a59a5687..504fdaa8367e 100644 --- a/arch/arm64/kernel/cpuinfo.c +++ b/arch/arm64/kernel/cpuinfo.c @@ -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); - if (l1ip != ICACHE_POLICY_PIPT) - 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); + } if (l1ip == ICACHE_POLICY_AIVIVT) set_bit(ICACHEF_AIVIVT, &__icache_flags); |