[v7,02/11] target-arm: Add SCR_EL3

diff --git a/target-arm/cpu.h b/target-arm/cpu.h
index 36507f9..c69d471 100644
--- a/target-arm/cpu.h
+++ b/target-arm/cpu.h
@@ -172,7 +172,6 @@  typedef struct CPUARMState {
         uint64_t c1_sys; /* System control register.  */
         uint64_t c1_coproc; /* Coprocessor access register.  */
         uint32_t c1_xscaleauxcr; /* XScale auxiliary control register.  */
-        uint32_t c1_scr; /* secure config register.  */
         uint64_t ttbr0_el1; /* MMU translation table base 0. */
         uint64_t ttbr1_el1; /* MMU translation table base 1. */
         uint64_t c2_control; /* MMU translation table base control.  */
@@ -185,6 +184,7 @@  typedef struct CPUARMState {
         uint32_t pmsav5_data_ap; /* PMSAv5 MPU data access permissions */
         uint32_t pmsav5_insn_ap; /* PMSAv5 MPU insn access permissions */
         uint64_t hcr_el2; /* Hypervisor configuration register */
+        uint64_t scr_el3; /* Secure configuration register.  */
         uint32_t ifsr_el2; /* Fault status registers.  */
         uint64_t esr_el[4];
         uint32_t c6_region[8]; /* MPU base/size registers.  */
@@ -601,6 +601,23 @@  static inline void xpsr_write(CPUARMState *env, uint32_t val, uint32_t mask)
 #define HCR_ID        (1ULL << 33)
 #define HCR_MASK      ((1ULL << 34) - 1)
 
+#define SCR_NS                (1U << 0)
+#define SCR_IRQ               (1U << 1)
+#define SCR_FIQ               (1U << 2)
+#define SCR_EA                (1U << 3)
+#define SCR_FW                (1U << 4)
+#define SCR_AW                (1U << 5)
+#define SCR_NET               (1U << 6)
+#define SCR_SMD               (1U << 7)
+#define SCR_HCE               (1U << 8)
+#define SCR_SIF               (1U << 9)
+#define SCR_RW                (1U << 10)
+#define SCR_ST                (1U << 11)
+#define SCR_TWI               (1U << 12)
+#define SCR_TWE               (1U << 13)
+#define SCR_AARCH32_MASK      (0x3fff & ~(SCR_RW | SCR_ST))
+#define SCR_AARCH64_MASK      (0x3fff & ~SCR_NET)
+
 /* Return the current FPSCR value.  */
 uint32_t vfp_get_fpscr(CPUARMState *env);
 void vfp_set_fpscr(CPUARMState *env, uint32_t val);
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 40b0c5f..11e8fa6 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -747,6 +747,32 @@  static void vbar_write(CPUARMState *env, const ARMCPRegInfo *ri,
     raw_write(env, ri, value & ~0x1FULL);
 }
 
+static void scr_write(CPUARMState *env, const ARMCPRegInfo *ri, uint64_t value)
+{
+    /* We only mask off bits that are RES0 both for AArch64 and AArch32.
+     * For bits that vary between AArch32/64, code needs to check the
+     * current execution mode before directly using the feature bit.
+     */
+    uint32_t valid_mask = SCR_AARCH64_MASK | SCR_AARCH32_MASK;
+
+    if (!arm_feature(env, ARM_FEATURE_EL2)) {
+        valid_mask &= ~SCR_HCE;
+
+        /* On ARMv7, SMD (or SCD as it is called in v7) is only
+         * supported if EL2 exists. The bit is UNK/SBZP when
+         * EL2 is unavailable. In QEMU ARMv7, we force it to always zero
+         * when EL2 is unavailable.
+         */
+        if (arm_feature(env, ARM_FEATURE_V7)) {
+            valid_mask &= ~SCR_SMD;
+        }
+    }
+
+    /* Clear all-context RES0 bits.  */
+    value &= valid_mask;
+    raw_write(env, ri, value);
+}
+
 static uint64_t ccsidr_read(CPUARMState *env, const ARMCPRegInfo *ri)
 {
     ARMCPU *cpu = arm_env_get_cpu(env);
@@ -873,8 +899,8 @@  static const ARMCPRegInfo v7_cp_reginfo[] = {
       .fieldoffset = offsetof(CPUARMState, cp15.vbar_el[1]),
       .resetvalue = 0 },
     { .name = "SCR", .cp = 15, .crn = 1, .crm = 1, .opc1 = 0, .opc2 = 0,
-      .access = PL1_RW, .fieldoffset = offsetof(CPUARMState, cp15.c1_scr),
-      .resetvalue = 0, },
+      .access = PL1_RW, .fieldoffset = offsetof(CPUARMState, cp15.scr_el3),
+      .resetvalue = 0, .writefn = scr_write },
     { .name = "CCSIDR", .state = ARM_CP_STATE_BOTH,
       .opc0 = 3, .crn = 0, .crm = 0, .opc1 = 1, .opc2 = 0,
       .access = PL1_R, .readfn = ccsidr_read, .type = ARM_CP_NO_MIGRATE },
@@ -2314,6 +2340,11 @@  static const ARMCPRegInfo v8_el3_cp_reginfo[] = {
       .access = PL3_RW, .writefn = vbar_write,
       .fieldoffset = offsetof(CPUARMState, cp15.vbar_el[3]),
       .resetvalue = 0 },
+    { .name = "SCR_EL3", .state = ARM_CP_STATE_AA64,
+      .type = ARM_CP_NO_MIGRATE,
+      .opc0 = 3, .opc1 = 6, .crn = 1, .crm = 1, .opc2 = 0,
+      .access = PL3_RW, .fieldoffset = offsetoflow32(CPUARMState, cp15.scr_el3),
+      .writefn = scr_write },
     REGINFO_SENTINEL
 };