Thread (11 messages) 11 messages, 4 authors, 2018-05-24

[PATCH v3 1/6] arm64: cpufeature: Allow early detect of specific features

From: Suzuki.Poulose@arm.com (Suzuki K Poulose)
Date: 2018-05-21 11:45:30
Also in: lkml

On 21/05/18 12:35, Julien Thierry wrote:
From: Daniel Thompson <redacted>

Currently it is not possible to detect features of the boot CPU
until the other CPUs have been brought up.

This prevents us from reacting to features of the boot CPU until
fairly late in the boot process. To solve this we allow a subset
of features (that are likely to be common to all clusters) to be
detected based on the boot CPU alone.

Signed-off-by: Daniel Thompson <redacted>
[julien.thierry at arm.com: check non-boot cpu missing early features, avoid
			 duplicates between early features and normal
			 features]
Signed-off-by: Julien Thierry <redacted>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <redacted>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
nit: Since this is completely different from what Daniel started with,
you could simply reset the author to yourself. The boot CPU feature was
added keeping this user in mind.

The patch as such looks good to me.

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
quoted hunk ↗ jump to hunk
---
  arch/arm64/kernel/cpufeature.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 9d1b06d..e03e897 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1030,7 +1030,7 @@ static void cpu_copy_el2regs(const struct arm64_cpu_capabilities *__unused)
  	{
  		.desc = "GIC system register CPU interface",
  		.capability = ARM64_HAS_SYSREG_GIC_CPUIF,
-		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
+		.type = ARM64_CPUCAP_STRICT_BOOT_CPU_FEATURE,
  		.matches = has_useable_gicv3_cpuif,
  		.sys_reg = SYS_ID_AA64PFR0_EL1,
  		.field_pos = ID_AA64PFR0_GIC_SHIFT,
--
1.9.1
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