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authorPeter Maydell <peter.maydell@linaro.org>2025-08-19 15:56:58 +0100
committerPeter Maydell <peter.maydell@linaro.org>2025-08-30 16:37:23 +0100
commitc2fae597099ef6ff81ca63d69ee28eddb982d894 (patch)
tree888a0048d2b790704db53f924cbe6a04607634ba
parente0ca100425853aa362acefeb027800d952fb222d (diff)
downloadfocaccia-qemu-c2fae597099ef6ff81ca63d69ee28eddb982d894.tar.gz
focaccia-qemu-c2fae597099ef6ff81ca63d69ee28eddb982d894.zip
target/arm: Correct condition of aa64_atomics feature function
The ARMv8.1-Atomics feature (renamed FEAT_LSE in more modern versions
of the Arm ARM) has always ben indicated by ID_AA64ISAR0.ATOMIC being
0b0010 or greater; 0b0001 is a reserved unused value.

We were incorrectly checking for != 0; this had no harmful effects
because all the CPUs set their value for this field to either 0
(for not having the feature) or 2 (if they do have it), but it's
better to match what the architecture specifies here.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250819145659.2165160-1-peter.maydell@linaro.org
-rw-r--r--target/arm/cpu-features.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/target/arm/cpu-features.h b/target/arm/cpu-features.h
index 41511d0835..d48754bcf2 100644
--- a/target/arm/cpu-features.h
+++ b/target/arm/cpu-features.h
@@ -408,7 +408,7 @@ static inline bool isar_feature_aa64_crc32(const ARMISARegisters *id)
 
 static inline bool isar_feature_aa64_atomics(const ARMISARegisters *id)
 {
-    return FIELD_EX64_IDREG(id, ID_AA64ISAR0, ATOMIC) != 0;
+    return FIELD_EX64_IDREG(id, ID_AA64ISAR0, ATOMIC) >= 2;
 }
 
 static inline bool isar_feature_aa64_rdm(const ARMISARegisters *id)