[PATCH v2 1/7] target/arm: v8.3 PAC ID_AA64ISAR[12] feature-detection

[Aaron Lindsay <aaron@os.amperecomputing.com>]

Signed-off-by: Aaron Lindsay <aaron@os.amperecomputing.com>
---
 target/arm/cpu.h          | 61 +++++++++++++++++++++++++++++++++++++--
 target/arm/helper.c       |  4 +--
 target/arm/pauth_helper.c |  2 +-
 3 files changed, 61 insertions(+), 6 deletions(-)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 8cf70693be..9c3cbc9a29 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -1001,6 +1001,7 @@ struct ArchCPU {
         uint32_t dbgdevid1;
         uint64_t id_aa64isar0;
         uint64_t id_aa64isar1;
+        uint64_t id_aa64isar2;
         uint64_t id_aa64pfr0;
         uint64_t id_aa64pfr1;
         uint64_t id_aa64mmfr0;
@@ -3902,18 +3903,72 @@ static inline bool isar_feature_aa64_pauth(const ARMISARegisters *id)
             (FIELD_DP64(0, ID_AA64ISAR1, APA, 0xf) |
              FIELD_DP64(0, ID_AA64ISAR1, API, 0xf) |
              FIELD_DP64(0, ID_AA64ISAR1, GPA, 0xf) |
-             FIELD_DP64(0, ID_AA64ISAR1, GPI, 0xf))) != 0;
+             FIELD_DP64(0, ID_AA64ISAR1, GPI, 0xf))) != 0 ||
+           (id->id_aa64isar2 &
+            (FIELD_DP64(0, ID_AA64ISAR2, APA3, 0xf) |
+             FIELD_DP64(0, ID_AA64ISAR2, GPA3, 0xf))) != 0;
 }
 
-static inline bool isar_feature_aa64_pauth_arch(const ARMISARegisters *id)
+static inline bool isar_feature_aa64_pauth_arch_qarma5(const ARMISARegisters *id)
 {
     /*
-     * Return true if pauth is enabled with the architected QARMA algorithm.
+     * Return true if pauth is enabled with the architected QARMA5 algorithm.
      * QEMU will always set APA+GPA to the same value.
      */
     return FIELD_EX64(id->id_aa64isar1, ID_AA64ISAR1, APA) != 0;
 }
 
+static inline bool isar_feature_aa64_pauth_arch_qarma3(const ARMISARegisters *id)
+{
+    /*
+     * Return true if pauth is enabled with the architected QARMA3 algorithm.
+     * QEMU will always set APA3+GPA3 to the same value.
+     */
+    return FIELD_EX64(id->id_aa64isar2, ID_AA64ISAR2, APA3) != 0;
+}
+
+static inline bool isar_feature_aa64_pauth_arch(const ARMISARegisters *id)
+{
+    return isar_feature_aa64_pauth_arch_qarma5(id) ||
+        isar_feature_aa64_pauth_arch_qarma3(id);
+}
+
+static inline uint8_t isar_feature_pauth_get_features(const ARMISARegisters *id)
+{
+    if (isar_feature_aa64_pauth_arch_qarma5(id))
+        return FIELD_EX64(id->id_aa64isar1, ID_AA64ISAR1, APA);
+    else if (isar_feature_aa64_pauth_arch_qarma3(id))
+        return FIELD_EX64(id->id_aa64isar2, ID_AA64ISAR2, APA3);
+    else
+        return FIELD_EX64(id->id_aa64isar1, ID_AA64ISAR1, API);
+}
+
+static inline bool isar_feature_aa64_pauth_epac(const ARMISARegisters *id)
+{
+    /*
+     * Note that unlike most AArch64 features, EPAC is treated (in the ARM
+     * psedocode, at least) as not being implemented by larger values of this
+     * field. Our usage of '>=' rather than '==' here causes our implementation
+     * of PAC logic to diverge slightly from ARM pseudocode.
+     */
+    return isar_feature_pauth_get_features(id) >= 0b0010;
+}
+
+static inline bool isar_feature_aa64_pauth2(const ARMISARegisters *id)
+{
+    return isar_feature_pauth_get_features(id) >= 0b0011;
+}
+
+static inline bool isar_feature_aa64_fpac(const ARMISARegisters *id)
+{
+    return isar_feature_pauth_get_features(id) >= 0b0100;
+}
+
+static inline bool isar_feature_aa64_fpac_combine(const ARMISARegisters *id)
+{
+    return isar_feature_pauth_get_features(id) >= 0b0101;
+}
+
 static inline bool isar_feature_aa64_tlbirange(const ARMISARegisters *id)
 {
     return FIELD_EX64(id->id_aa64isar0, ID_AA64ISAR0, TLB) == 2;
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 72b37b7cf1..448ebf8301 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -8028,11 +8028,11 @@ void register_cp_regs_for_features(ARMCPU *cpu)
               .access = PL1_R, .type = ARM_CP_CONST,
               .accessfn = access_aa64_tid3,
               .resetvalue = cpu->isar.id_aa64isar1 },
-            { .name = "ID_AA64ISAR2_EL1_RESERVED", .state = ARM_CP_STATE_AA64,
+            { .name = "ID_AA64ISAR2_EL1", .state = ARM_CP_STATE_AA64,
               .opc0 = 3, .opc1 = 0, .crn = 0, .crm = 6, .opc2 = 2,
               .access = PL1_R, .type = ARM_CP_CONST,
               .accessfn = access_aa64_tid3,
-              .resetvalue = 0 },
+              .resetvalue = cpu->isar.id_aa64isar2 },
             { .name = "ID_AA64ISAR3_EL1_RESERVED", .state = ARM_CP_STATE_AA64,
               .opc0 = 3, .opc1 = 0, .crn = 0, .crm = 6, .opc2 = 3,
               .access = PL1_R, .type = ARM_CP_CONST,
diff --git a/target/arm/pauth_helper.c b/target/arm/pauth_helper.c
index d0483bf051..e5206453f6 100644
--- a/target/arm/pauth_helper.c
+++ b/target/arm/pauth_helper.c
@@ -282,7 +282,7 @@ static uint64_t pauth_computepac_impdef(uint64_t data, uint64_t modifier,
 static uint64_t pauth_computepac(CPUARMState *env, uint64_t data,
                                  uint64_t modifier, ARMPACKey key)
 {
-    if (cpu_isar_feature(aa64_pauth_arch, env_archcpu(env))) {
+    if (cpu_isar_feature(aa64_pauth_arch_qarma5, env_archcpu(env))) {
         return pauth_computepac_architected(data, modifier, key);
     } else {
         return pauth_computepac_impdef(data, modifier, key);
-- 
2.25.1