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Commit e8002e02 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Will Deacon
Browse files

arm64/errata: add REVIDR handling to framework 



In some cases, core variants that are affected by a certain erratum
also exist in versions that have the erratum fixed, and this fact is
recorded in a dedicated bit in system register REVIDR_EL1.

Since the architecture does not require that a certain bit retains
its meaning across different variants of the same model, each such
REVIDR bit is tightly coupled to a certain revision/variant value,
and so we need a list of revidr_mask/midr pairs to carry this
information.

So add the struct member and the associated macros and handling to
allow REVIDR fixes to be taken into account.

Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent a257e025

arch/arm64/include/asm/cpufeature.h

+4 −0
Original line number Diff line number Diff line
@@ -105,6 +105,10 @@ struct arm64_cpu_capabilities { 
		struct {	/* To be used for erratum handling only */

			u32 midr_model;

			u32 midr_range_min, midr_range_max;

			const struct arm64_midr_revidr {

				u32 midr_rv;		/* revision/variant */

				u32 revidr_mask;

			} * const fixed_revs;

		};



		struct {	/* Feature register checking */

arch/arm64/kernel/cpu_errata.c

+18 −3
Original line number Diff line number Diff line
@@ -24,10 +24,22 @@ 
static bool __maybe_unused

is_affected_midr_range(const struct arm64_cpu_capabilities *entry, int scope)

{

	const struct arm64_midr_revidr *fix;

	u32 midr = read_cpuid_id(), revidr;



	WARN_ON(scope != SCOPE_LOCAL_CPU || preemptible());

	return MIDR_IS_CPU_MODEL_RANGE(read_cpuid_id(), entry->midr_model,

	if (!MIDR_IS_CPU_MODEL_RANGE(midr, entry->midr_model,

				     entry->midr_range_min,

				       entry->midr_range_max);

				     entry->midr_range_max))

		return false;



	midr &= MIDR_REVISION_MASK | MIDR_VARIANT_MASK;

	revidr = read_cpuid(REVIDR_EL1);

	for (fix = entry->fixed_revs; fix && fix->revidr_mask; fix++)

		if (midr == fix->midr_rv && (revidr & fix->revidr_mask))

			return false;



	return true;

}



static bool __maybe_unused
@@ -242,6 +254,9 @@ static int qcom_enable_link_stack_sanitization(void *data) 
	.midr_range_min = 0, \

	.midr_range_max = (MIDR_VARIANT_MASK | MIDR_REVISION_MASK)



#define MIDR_FIXED(rev, revidr_mask) \

	.fixed_revs = (struct arm64_midr_revidr[]){{ (rev), (revidr_mask) }, {}}



const struct arm64_cpu_capabilities arm64_errata[] = {

#if	defined(CONFIG_ARM64_ERRATUM_826319) || \

	defined(CONFIG_ARM64_ERRATUM_827319) || \