target/arm: When tag memory is not present, set MTE=1
When the cpu support MTE, but the system does not, reduce cpu
support to user instructions at EL0 instead of completely
disabling MTE. If we encounter a cpu implementation which does
something else, we can revisit this setting.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20230811214031.171020-5-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index fe73fd8..2390112 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -2067,12 +2067,13 @@
#ifndef CONFIG_USER_ONLY
/*
- * Disable the MTE feature bits if we do not have tag-memory
- * provided by the machine.
+ * If we do not have tag-memory provided by the machine,
+ * reduce MTE support to instructions enabled at EL0.
+ * This matches Cortex-A710 BROADCASTMTE input being LOW.
*/
if (cpu->tag_memory == NULL) {
cpu->isar.id_aa64pfr1 =
- FIELD_DP64(cpu->isar.id_aa64pfr1, ID_AA64PFR1, MTE, 0);
+ FIELD_DP64(cpu->isar.id_aa64pfr1, ID_AA64PFR1, MTE, 1);
}
#endif
}
