[PATCH v3 09/12] arm64: cpufeature: Ensure atomic updates to system_cpucaps bitmap

[Jinjie Ruan]

Parallel CPU bringup allows multiple secondary CPUs to concurrently
execute update_cpu_capabilities() during early boot.

The current non-atomic __set_bit() and __clear_bit() helpers perform
unserialized updates on the shared global bitmap, risking data races
and feature flag erasure.

Upgrade these operations to set_bit() and clear_bit() to ensure all
concurrent modifications are properly serialized via arm64 atomics.

Signed-off-by: Jinjie Ruan <ruanjinjie at huawei.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 be75e60d56ca..a1a13f3e01ed 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -3548,7 +3548,7 @@ static void update_cpu_capabilities(u16 scope_mask)
 
 		if (!caps->matches(caps, cpucap_default_scope(caps))) {
 			if (match_all)
-				__clear_bit(caps->capability, system_cpucaps);
+				clear_bit(caps->capability, system_cpucaps);
 			continue;
 		}
 
@@ -3559,7 +3559,7 @@ static void update_cpu_capabilities(u16 scope_mask)
 		if (!match_all && caps->desc && !caps->cpus)
 			pr_info("detected: %s\n", caps->desc);
 
-		__set_bit(caps->capability, system_cpucaps);
+		set_bit(caps->capability, system_cpucaps);
 
 		if (boot_cpu && (caps->type & SCOPE_BOOT_CPU))
 			set_bit(caps->capability, boot_cpucaps);
-- 
2.34.1