target/arm: Implement v8M MSPLIM and PSPLIM registers

The v8M architecture includes hardware support for enforcing
stack pointer limits. We don't implement this behaviour yet,
but provide the MSPLIM and PSPLIM stack pointer limit registers
as reads-as-written, so that when we do implement the checks
in future this won't break guest migration.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20180209165810.6668-12-peter.maydell@linaro.org

1 files changed, 21 insertions, 0 deletions

diff --git a/target/arm/machine.c b/target/arm/machine.c
index 1a20d6c36c..2e28d086bd 100644
--- a/target/arm/machine.c
+++ b/target/arm/machine.c
@@ -246,6 +246,26 @@ static const VMStateDescription vmstate_m_other_sp = {
     }
 };
 
+static bool m_v8m_needed(void *opaque)
+{
+    ARMCPU *cpu = opaque;
+    CPUARMState *env = &cpu->env;
+
+    return arm_feature(env, ARM_FEATURE_M) && arm_feature(env, ARM_FEATURE_V8);
+}
+
+static const VMStateDescription vmstate_m_v8m = {
+    .name = "cpu/m/v8m",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = m_v8m_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32_ARRAY(env.v7m.msplim, ARMCPU, M_REG_NUM_BANKS),
+        VMSTATE_UINT32_ARRAY(env.v7m.psplim, ARMCPU, M_REG_NUM_BANKS),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static const VMStateDescription vmstate_m = {
     .name = "cpu/m",
     .version_id = 4,
@@ -270,6 +290,7 @@ static const VMStateDescription vmstate_m = {
         &vmstate_m_csselr,
         &vmstate_m_scr,
         &vmstate_m_other_sp,
+        &vmstate_m_v8m,
         NULL
     }
 };