target/arm: Add ID register values for Cortex-M0

Give the Cortex-M0 ID register values corresponding to its
implemented behaviour.  These will not be guest-visible but will be
used to govern the behaviour of QEMU's emulation.  We use the same
values that the Cortex-M3 does.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200910173855.4068-5-peter.maydell@linaro.org

diff --git a/target/arm/cpu_tcg.c b/target/arm/cpu_tcg.c
index a9b7cf52550b7cf78b731b8a6d7dd7d44f1219ce..0013e25412f8943c4d9f052dcf1b53cd60297eb6 100644 (file)
--- a/target/arm/cpu_tcg.c
+++ b/target/arm/cpu_tcg.c
@@ -256,6 +256,30 @@ static void cortex_m0_initfn(Object *obj)
     set_feature(&cpu->env, ARM_FEATURE_M);
 
     cpu->midr = 0x410cc200;
+
+    /*
+     * These ID register values are not guest visible, because
+     * we do not implement the Main Extension. They must be set
+     * to values corresponding to the Cortex-M0's implemented
+     * features, because QEMU generally controls its emulation
+     * by looking at ID register fields. We use the same values as
+     * for the M3.
+     */
+    cpu->isar.id_pfr0 = 0x00000030;
+    cpu->isar.id_pfr1 = 0x00000200;
+    cpu->isar.id_dfr0 = 0x00100000;
+    cpu->id_afr0 = 0x00000000;
+    cpu->isar.id_mmfr0 = 0x00000030;
+    cpu->isar.id_mmfr1 = 0x00000000;
+    cpu->isar.id_mmfr2 = 0x00000000;
+    cpu->isar.id_mmfr3 = 0x00000000;
+    cpu->isar.id_isar0 = 0x01141110;
+    cpu->isar.id_isar1 = 0x02111000;
+    cpu->isar.id_isar2 = 0x21112231;
+    cpu->isar.id_isar3 = 0x01111110;
+    cpu->isar.id_isar4 = 0x01310102;
+    cpu->isar.id_isar5 = 0x00000000;
+    cpu->isar.id_isar6 = 0x00000000;
 }
 
 static void cortex_m3_initfn(Object *obj)