target-arm: Implement AArch64 memory attribute registers

Implement the AArch64 memory attribute registers. Since QEMU doesn't
model caches it does not need to care about memory attributes at all,
and we can simply make these read-as-written.

We did not previously implement the AArch32 versions of the MAIR
registers, which went unnoticed because of the overbroad TLB_LOCKDOWN
reginfo definition; provide them now to keep the 64<->32 register
relationship clear.

We already provided AMAIR registers for 32 bit as simple RAZ/WI;
extend that to provide a 64 bit RAZ/WI AMAIR_EL1.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>

target-arm/cpu.h

@@ -74,8 +74,10 @@
  */
 #ifdef HOST_WORDS_BIGENDIAN
 #define offsetoflow32(S, M) (offsetof(S, M) + sizeof(uint32_t))
+#define offsetofhigh32(S, M) offsetof(S, M)
 #else
 #define offsetoflow32(S, M) offsetof(S, M)
+#define offsetofhigh32(S, M) (offsetof(S, M) + sizeof(uint32_t))
 #endif
 
 /* Meanings of the ARMCPU object's two inbound GPIO lines */
@@ -197,6 +199,7 @@ typedef struct CPUARMState {
         uint32_t c9_pmxevtyper; /* perf monitor event type */
         uint32_t c9_pmuserenr; /* perf monitor user enable */
         uint32_t c9_pminten; /* perf monitor interrupt enables */
+        uint64_t mair_el1;
         uint32_t c12_vbar; /* vector base address register */
         uint32_t c13_fcse; /* FCSE PID.  */
         uint32_t c13_context; /* Context ID.  */

target-arm/helper.c

@@ -641,6 +641,26 @@ static const ARMCPRegInfo v7_cp_reginfo[] = {
      */
     { .name = "AIDR", .cp = 15, .crn = 0, .crm = 0, .opc1 = 1, .opc2 = 7,
       .access = PL1_R, .type = ARM_CP_CONST, .resetvalue = 0 },
+    /* MAIR can just read-as-written because we don't implement caches
+     * and so don't need to care about memory attributes.
+     */
+    { .name = "MAIR_EL1", .state = ARM_CP_STATE_AA64,
+      .opc0 = 3, .opc1 = 0, .crn = 10, .crm = 2, .opc2 = 0,
+      .access = PL1_RW, .fieldoffset = offsetof(CPUARMState, cp15.mair_el1),
+      .resetvalue = 0 },
+    /* For non-long-descriptor page tables these are PRRR and NMRR;
+     * regardless they still act as reads-as-written for QEMU.
+     * The override is necessary because of the overly-broad TLB_LOCKDOWN
+     * definition.
+     */
+    { .name = "MAIR0", .state = ARM_CP_STATE_AA32, .type = ARM_CP_OVERRIDE,
+      .cp = 15, .opc1 = 0, .crn = 10, .crm = 2, .opc2 = 0, .access = PL1_RW,
+      .fieldoffset = offsetoflow32(CPUARMState, cp15.mair_el1),
+      .resetfn = arm_cp_reset_ignore },
+    { .name = "MAIR1", .state = ARM_CP_STATE_AA32, .type = ARM_CP_OVERRIDE,
+      .cp = 15, .opc1 = 0, .crn = 10, .crm = 2, .opc2 = 1, .access = PL1_RW,
+      .fieldoffset = offsetofhigh32(CPUARMState, cp15.mair_el1),
+      .resetfn = arm_cp_reset_ignore },
     REGINFO_SENTINEL
 };
 
@@ -1467,9 +1487,11 @@ static const ARMCPRegInfo lpae_cp_reginfo[] = {
     /* NOP AMAIR0/1: the override is because these clash with the rather
      * broadly specified TLB_LOCKDOWN entry in the generic cp_reginfo.
      */
-    { .name = "AMAIR0", .cp = 15, .crn = 10, .crm = 3, .opc1 = 0, .opc2 = 0,
+    { .name = "AMAIR0", .state = ARM_CP_STATE_BOTH,
+      .opc0 = 3, .crn = 10, .crm = 3, .opc1 = 0, .opc2 = 0,
       .access = PL1_RW, .type = ARM_CP_CONST | ARM_CP_OVERRIDE,
       .resetvalue = 0 },
+    /* AMAIR1 is mapped to AMAIR_EL1[63:32] */
     { .name = "AMAIR1", .cp = 15, .crn = 10, .crm = 3, .opc1 = 0, .opc2 = 1,
       .access = PL1_RW, .type = ARM_CP_CONST | ARM_CP_OVERRIDE,
       .resetvalue = 0 },