target/arm: Advertise Cortex-A53 erratum #843419 fix via REVIDR

The Cortex-A53 r0p4 revision that QEMU emulates is affected by a CatA
erratum #843419 (i.e., the most severe), which requires workarounds in
the toolchain as well as the OS.

Since the emulation is obviously not affected in the same way, we can
indicate this via REVIDR bit #8, which on r0p4 has the meaning that no
workarounds for erratum #843419 are needed.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240215160202.2803452-1-ardb+git@google.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

target/arm/cpu64.c

@@ -663,7 +663,7 @@ static void aarch64_a53_initfn(Object *obj)
     set_feature(&cpu->env, ARM_FEATURE_PMU);
     cpu->kvm_target = QEMU_KVM_ARM_TARGET_CORTEX_A53;
     cpu->midr = 0x410fd034;
-    cpu->revidr = 0x00000000;
+    cpu->revidr = 0x00000100;
     cpu->reset_fpsid = 0x41034070;
     cpu->isar.mvfr0 = 0x10110222;
     cpu->isar.mvfr1 = 0x12111111;