Re: [PATCH] arm64: cpufeature: Enable Qualcomm erratas

Will Deacon
2019-10-29T11:40:06Z

On Mon, Oct 28, 2019 at 11:04:32PM -0700, Bjorn Andersson wrote:
> With the introduction of 'cce360b54ce6 ("arm64: capabilities: Filter the
> entries based on a given mask")' the Qualcomm erratas are no long
> applied.
>
> The result of not applying errata 1003 is that MSM8996 runs into various
> RCU stalls and fails to boot most of the times.
>
> Give both 1003 and 1009 a "type" to ensure they are not filtered out in
> update_cpu_capabilities().

Oh nasty. Thanks for debugging and fixing this.

> Fixes: cce360b54ce6 ("arm64: capabilities: Filter the entries based on a given mask")
> Cc: stable@vger.kernel.org
> Reported-by: Mark Brown <broonie@kernel.org>
> Suggested-by: Will Deacon <will@kernel.org>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
> arch/arm64/kernel/cpu_errata.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
> index df9465120e2f..cdd8df033536 100644
> --- a/arch/arm64/kernel/cpu_errata.c
> +++ b/arch/arm64/kernel/cpu_errata.c
> @@ -780,6 +780,7 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
> {
> .desc = "Qualcomm Technologies Falkor/Kryo erratum 1003",
> .capability = ARM64_WORKAROUND_QCOM_FALKOR_E1003,
> + .type = ARM64_CPUCAP_SCOPE_LOCAL_CPU,
> .matches = cpucap_multi_entry_cap_matches,

This should probably be ARM64_CPUCAP_LOCAL_CPU_ERRATUM instead, but I'll
want Suzuki's ack before I take the change.

> .match_list = qcom_erratum_1003_list,
> },
> @@ -788,6 +789,7 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
> {
> .desc = "Qualcomm erratum 1009, ARM erratum 1286807",
> .capability = ARM64_WORKAROUND_REPEAT_TLBI,
> + .type = ARM64_CPUCAP_SCOPE_LOCAL_CPU,
> ERRATA_MIDR_RANGE_LIST(arm64_repeat_tlbi_cpus),

ERRATA_MIDR_RANGE_LIST sets the type already, so I think this is redundant.

Will