hw/intc/armv7m_nvic: Implement cache ID registers

M profile cores have a similar setup for cache ID registers
to A profile:
 * Cache Level ID Register (CLIDR) is a fixed value
 * Cache Type Register (CTR) is a fixed value
 * Cache Size ID Registers (CCSIDR) are a bank of registers;
   which one you see is selected by the Cache Size Selection
   Register (CSSELR)

The only difference is that they're in the NVIC memory mapped
register space rather than being coprocessor registers.
Implement the M profile view of them.

Since neither Cortex-M3 nor Cortex-M4 implement caches,
we don't need to update their init functions and can leave
the ctr/clidr/ccsidr[] fields in their ARMCPU structs at zero.
Newer cores (like the Cortex-M33) will want to be able to
set these ID registers to non-zero values, though.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20180209165810.6668-6-peter.maydell@linaro.org

1 files changed, 36 insertions, 0 deletions

diff --git a/target/arm/machine.c b/target/arm/machine.c
index 2c8b43062f..cae63c2f98 100644
--- a/target/arm/machine.c
+++ b/target/arm/machine.c
@@ -191,6 +191,41 @@ static const VMStateDescription vmstate_m_faultmask_primask = {
     }
 };
 
+/* CSSELR is in a subsection because we didn't implement it previously.
+ * Migration from an old implementation will leave it at zero, which
+ * is OK since the only CPUs in the old implementation make the
+ * register RAZ/WI.
+ * Since there was no version of QEMU which implemented the CSSELR for
+ * just non-secure, we transfer both banks here rather than putting
+ * the secure banked version in the m-security subsection.
+ */
+static bool csselr_vmstate_validate(void *opaque, int version_id)
+{
+    ARMCPU *cpu = opaque;
+
+    return cpu->env.v7m.csselr[M_REG_NS] <= R_V7M_CSSELR_INDEX_MASK
+        && cpu->env.v7m.csselr[M_REG_S] <= R_V7M_CSSELR_INDEX_MASK;
+}
+
+static bool m_csselr_needed(void *opaque)
+{
+    ARMCPU *cpu = opaque;
+
+    return !arm_v7m_csselr_razwi(cpu);
+}
+
+static const VMStateDescription vmstate_m_csselr = {
+    .name = "cpu/m/csselr",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .needed = m_csselr_needed,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32_ARRAY(env.v7m.csselr, ARMCPU, M_REG_NUM_BANKS),
+        VMSTATE_VALIDATE("CSSELR is valid", csselr_vmstate_validate),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static const VMStateDescription vmstate_m = {
     .name = "cpu/m",
     .version_id = 4,
@@ -212,6 +247,7 @@ static const VMStateDescription vmstate_m = {
     },
     .subsections = (const VMStateDescription*[]) {
         &vmstate_m_faultmask_primask,
+        &vmstate_m_csselr,
         NULL
     }
 };