[PATCH v3 10/13] arm64: Add MIDR-based override infrastructure

[Marc Zyngier <maz@kernel.org>]

In order to be able to use the override infrastructure to "fix"
CPUs that have deviated from the architecture spec, add a new
pile of hacks on top of the existing one, allowing a feature
to be overriden based on matching a MIDR list.

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kernel/idreg-override.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c
index 7b5b9dc20e6b..57c145bf50b7 100644
--- a/arch/arm64/kernel/idreg-override.c
+++ b/arch/arm64/kernel/idreg-override.c
@@ -321,6 +321,23 @@ static __init void parse_cmdline(void)
 		__parse_cmdline(prop, true);
 }
 
+struct midr_override_data {
+	const char		feature[FTR_ALIAS_OPTION_LEN];
+	const struct midr_range	ranges[];
+};
+
+static const struct midr_override_data * const midr_ovr_data[] __initconst = {
+};
+
+static void __init apply_midr_overrides(void)
+{
+	const u64 midr = read_cpuid_id();
+
+	for (int i = 0; i < ARRAY_SIZE(midr_ovr_data); i++)
+		if (is_midr_in_range_list(midr, midr_ovr_data[i]->ranges))
+			__parse_cmdline(midr_ovr_data[i]->feature, false);
+}
+
 /* Keep checkers quiet */
 void init_feature_override(u64 boot_status);
 
@@ -337,6 +354,8 @@ asmlinkage void __init init_feature_override(u64 boot_status)
 
 	__boot_status = boot_status;
 
+	apply_midr_overrides();
+
 	parse_cmdline();
 
 	for (i = 0; i < ARRAY_SIZE(regs); i++) {
-- 
2.39.2


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