target/arm: Implement FEAT_SCTLR2 and enable with -cpu max

Add FEAT_SCTLR2, which introduces the SCTLR2_EL1, SCTLR2_EL2, and
SCTLR2_EL3 registers. These registers are extensions of the SCTLR_ELx
ones.

Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250727074202.83141-4-richard.henderson@linaro.org
Message-ID: <20250711140828.1714666-4-gustavo.romero@linaro.org>
[rth: Remove FEAT_MEC code; handle SCR and HCRX enable bits.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 90 insertions, 7 deletions

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 0c1299ff84..11ddeabb13 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -741,6 +741,9 @@ static void scr_write(CPUARMState *env, const ARMCPRegInfo *ri, uint64_t value)
         if (cpu_isar_feature(aa64_ecv, cpu)) {
             valid_mask |= SCR_ECVEN;
         }
+        if (cpu_isar_feature(aa64_sctlr2, cpu)) {
+            valid_mask |= SCR_SCTLR2EN;
+        }
     } else {
         valid_mask &= ~(SCR_RW | SCR_ST);
         if (cpu_isar_feature(aa32_ras, cpu)) {
@@ -3907,23 +3910,21 @@ static void hcrx_write(CPUARMState *env, const ARMCPRegInfo *ri,
     ARMCPU *cpu = env_archcpu(env);
     uint64_t valid_mask = 0;
 
-    /* FEAT_MOPS adds MSCEn and MCE2 */
     if (cpu_isar_feature(aa64_mops, cpu)) {
         valid_mask |= HCRX_MSCEN | HCRX_MCE2;
     }
-
-    /* FEAT_NMI adds TALLINT, VINMI and VFNMI */
     if (cpu_isar_feature(aa64_nmi, cpu)) {
         valid_mask |= HCRX_TALLINT | HCRX_VINMI | HCRX_VFNMI;
     }
-    /* FEAT_CMOW adds CMOW */
     if (cpu_isar_feature(aa64_cmow, cpu)) {
         valid_mask |= HCRX_CMOW;
     }
-    /* FEAT_XS adds FGTnXS, FnXS */
     if (cpu_isar_feature(aa64_xs, cpu)) {
         valid_mask |= HCRX_FGTNXS | HCRX_FNXS;
     }
+    if (cpu_isar_feature(aa64_sctlr2, cpu)) {
+        valid_mask |= HCRX_SCTLR2EN;
+    }
 
     /* Clear RES0 bits.  */
     env->cp15.hcrx_el2 = value & valid_mask;
@@ -3981,11 +3982,16 @@ uint64_t arm_hcrx_el2_eff(CPUARMState *env)
      * This may need to be revisited for future bits.
      */
     if (!arm_is_el2_enabled(env)) {
+        ARMCPU *cpu = env_archcpu(env);
         uint64_t hcrx = 0;
-        if (cpu_isar_feature(aa64_mops, env_archcpu(env))) {
-            /* MSCEn behaves as 1 if EL2 is not enabled */
+
+        /* Bits which whose effective value is 1 if el2 not enabled. */
+        if (cpu_isar_feature(aa64_mops, cpu)) {
             hcrx |= HCRX_MSCEN;
         }
+        if (cpu_isar_feature(aa64_sctlr2, cpu)) {
+            hcrx |= HCRX_SCTLR2EN;
+        }
         return hcrx;
     }
     if (arm_feature(env, ARM_FEATURE_EL3) && !(env->cp15.scr_el3 & SCR_HXEN)) {
@@ -4513,6 +4519,8 @@ static void define_arm_vh_e2h_redirects_aliases(ARMCPU *cpu)
     static const struct E2HAlias aliases[] = {
         { K(3, 0,  1, 0, 0), K(3, 4,  1, 0, 0), K(3, 5, 1, 0, 0),
           "SCTLR", "SCTLR_EL2", "SCTLR_EL12" },
+        { K(3, 0,  1, 0, 3), K(3, 4,  1, 0, 3), K(3, 5, 1, 0, 3),
+          "SCTLR2_EL1", "SCTLR2_EL2", "SCTLR2_EL12", isar_feature_aa64_sctlr2 },
         { K(3, 0,  1, 0, 2), K(3, 4,  1, 1, 2), K(3, 5, 1, 0, 2),
           "CPACR", "CPTR_EL2", "CPACR_EL12" },
         { K(3, 0,  2, 0, 0), K(3, 4,  2, 0, 0), K(3, 5, 2, 0, 0),
@@ -5994,6 +6002,77 @@ static const ARMCPRegInfo actlr2_hactlr2_reginfo[] = {
       .resetvalue = 0 },
 };
 
+static CPAccessResult sctlr2_el2_access(CPUARMState *env,
+                                        const ARMCPRegInfo *ri,
+                                        bool isread)
+{
+    if (arm_current_el(env) < 3
+        && arm_feature(env, ARM_FEATURE_EL3)
+        && !(env->cp15.scr_el3 & SCR_SCTLR2EN)) {
+        return CP_ACCESS_TRAP_EL3;
+    }
+    return CP_ACCESS_OK;
+}
+
+static CPAccessResult sctlr2_el1_access(CPUARMState *env,
+                                        const ARMCPRegInfo *ri,
+                                        bool isread)
+{
+    CPAccessResult ret = access_tvm_trvm(env, ri, isread);
+    if (ret != CP_ACCESS_OK) {
+        return ret;
+    }
+    if (arm_current_el(env) < 2 && !(arm_hcrx_el2_eff(env) & HCRX_SCTLR2EN)) {
+        return CP_ACCESS_TRAP_EL2;
+    }
+    return sctlr2_el2_access(env, ri, isread);
+}
+
+static void sctlr2_el1_write(CPUARMState *env, const ARMCPRegInfo *ri,
+                             uint64_t value)
+{
+    uint64_t valid_mask = 0;
+
+    value &= valid_mask;
+    raw_write(env, ri, value);
+}
+
+static void sctlr2_el2_write(CPUARMState *env, const ARMCPRegInfo *ri,
+                             uint64_t value)
+{
+    uint64_t valid_mask = 0;
+
+    value &= valid_mask;
+    raw_write(env, ri, value);
+}
+
+static void sctlr2_el3_write(CPUARMState *env, const ARMCPRegInfo *ri,
+                             uint64_t value)
+{
+    uint64_t valid_mask = 0;
+
+    value &= valid_mask;
+    raw_write(env, ri, value);
+}
+
+static const ARMCPRegInfo sctlr2_reginfo[] = {
+    { .name = "SCTLR2_EL1", .state = ARM_CP_STATE_AA64,
+      .opc0 = 3, .opc1 = 0, .opc2 = 3, .crn = 1, .crm = 0,
+      .access = PL1_RW, .accessfn = sctlr2_el1_access,
+      .writefn = sctlr2_el1_write, .fgt = FGT_SCTLR_EL1,
+      .nv2_redirect_offset = 0x278 | NV2_REDIR_NV1,
+      .fieldoffset = offsetof(CPUARMState, cp15.sctlr2_el[1]) },
+    { .name = "SCTLR2_EL2", .state = ARM_CP_STATE_AA64,
+      .opc0 = 3, .opc1 = 4, .opc2 = 3, .crn = 1, .crm = 0,
+      .access = PL2_RW, .accessfn = sctlr2_el2_access,
+      .writefn = sctlr2_el2_write,
+      .fieldoffset = offsetof(CPUARMState, cp15.sctlr2_el[2]) },
+    { .name = "SCTLR2_EL3", .state = ARM_CP_STATE_AA64,
+      .opc0 = 3, .opc1 = 6, .opc2 = 3, .crn = 1, .crm = 0,
+      .access = PL3_RW, .writefn = sctlr2_el3_write,
+      .fieldoffset = offsetof(CPUARMState, cp15.sctlr2_el[3]) },
+};
+
 void register_cp_regs_for_features(ARMCPU *cpu)
 {
     /* Register all the coprocessor registers based on feature bits */
@@ -7223,6 +7302,10 @@ void register_cp_regs_for_features(ARMCPU *cpu)
         define_arm_cp_regs(cpu, nmi_reginfo);
     }
 
+    if (cpu_isar_feature(aa64_sctlr2, cpu)) {
+        define_arm_cp_regs(cpu, sctlr2_reginfo);
+    }
+
     if (cpu_isar_feature(any_predinv, cpu)) {
         define_arm_cp_regs(cpu, predinv_reginfo);
     }