[SRU][Bionic][PATCH 1/2] arm64: Check for errata before evaluating cpu features

[Juerg Haefliger]

From: Dirk Mueller <dmueller at suse.com>

BugLink: https://bugs.launchpad.net/bugs/1857074
BugLink: https://bugs.launchpad.net/bugs/1853485
BugLink: https://bugs.launchpad.net/bugs/1853326

Since commit d3aec8a28be3b8 ("arm64: capabilities: Restrict KPTI
detection to boot-time CPUs") we rely on errata flags being already
populated during feature enumeration. The order of errata and
features was flipped as part of commit ed478b3f9e4a ("arm64:
capabilities: Group handling of features and errata workarounds").

Return to the orginal order of errata and feature evaluation to
ensure errata flags are present during feature evaluation.

Fixes: ed478b3f9e4a ("arm64: capabilities: Group handling of
    features and errata workarounds")
CC: Suzuki K Poulose <suzuki.poulose at arm.com>
CC: Marc Zyngier <marc.zyngier at arm.com>
Signed-off-by: Dirk Mueller <dmueller at suse.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose at arm.com>
Signed-off-by: Will Deacon <will.deacon at arm.com>

(cherry picked from commit dc0e36581eb2da1aa3c63ceeff0f10ef1e899b2a)
Signed-off-by: Juerg Haefliger <juergh at canonical.com>
---
 arch/arm64/kernel/cpufeature.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index b96d1a635a16..3d332823ba93 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1360,9 +1360,9 @@ static void __update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
 
 static void update_cpu_capabilities(u16 scope_mask)
 {
-	__update_cpu_capabilities(arm64_features, scope_mask, "detected:");
 	__update_cpu_capabilities(arm64_errata, scope_mask,
 				  "enabling workaround for");
+	__update_cpu_capabilities(arm64_features, scope_mask, "detected:");
 }
 
 static int __enable_cpu_capability(void *arg)
@@ -1417,8 +1417,8 @@ __enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
 
 static void __init enable_cpu_capabilities(u16 scope_mask)
 {
-	__enable_cpu_capabilities(arm64_features, scope_mask);
 	__enable_cpu_capabilities(arm64_errata, scope_mask);
+	__enable_cpu_capabilities(arm64_features, scope_mask);
 }
 
 /*
-- 
2.20.1