[PATCH v3 7/8] target/arm: Implement v8.3 FPAC and FPACCOMBINE

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

Signed-off-by: Aaron Lindsay <aaron@os.amperecomputing.com>
---
 target/arm/syndrome.h         |  7 +++++++
 target/arm/tcg/pauth_helper.c | 16 ++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/target/arm/syndrome.h b/target/arm/syndrome.h
index d27d1bc31f..bf79c539d9 100644
--- a/target/arm/syndrome.h
+++ b/target/arm/syndrome.h
@@ -49,6 +49,7 @@ enum arm_exception_class {
     EC_SYSTEMREGISTERTRAP     = 0x18,
     EC_SVEACCESSTRAP          = 0x19,
     EC_ERETTRAP               = 0x1a,
+    EC_PACFAIL                = 0x1c,
     EC_SMETRAP                = 0x1d,
     EC_INSNABORT              = 0x20,
     EC_INSNABORT_SAME_EL      = 0x21,
@@ -231,6 +232,12 @@ static inline uint32_t syn_smetrap(SMEExceptionType etype, bool is_16bit)
         | (is_16bit ? 0 : ARM_EL_IL) | etype;
 }
 
+static inline uint32_t syn_pacfail(bool data, int keynumber)
+{
+    int error_code = (data << 1) | keynumber;
+    return (EC_PACFAIL << ARM_EL_EC_SHIFT) | ARM_EL_IL | error_code;
+}
+
 static inline uint32_t syn_pactrap(void)
 {
     return EC_PACTRAP << ARM_EL_EC_SHIFT;
diff --git a/target/arm/tcg/pauth_helper.c b/target/arm/tcg/pauth_helper.c
index 90ad6453e5..bb3dc7ff54 100644
--- a/target/arm/tcg/pauth_helper.c
+++ b/target/arm/tcg/pauth_helper.c
@@ -411,6 +411,13 @@ uint64_t pauth_ptr_mask(CPUARMState *env, uint64_t ptr, bool data)
     return pauth_ptr_mask_internal(param);
 }
 
+static G_NORETURN
+void pauth_fail_exception(CPUARMState *env, bool data, int keynumber, uintptr_t ra)
+{
+    int target_el = exception_target_el(env);
+    raise_exception_ra(env, EXCP_UDEF, syn_pacfail(data, keynumber), target_el, ra);
+}
+
 static uint64_t pauth_auth(CPUARMState *env, uint64_t ptr, uint64_t modifier,
                            ARMPACKey *key, bool data, int keynumber,
                            uintptr_t ra, bool is_combined)
@@ -430,6 +437,15 @@ static uint64_t pauth_auth(CPUARMState *env, uint64_t ptr, uint64_t modifier,
         uint64_t xor_mask = MAKE_64BIT_MASK(bot_bit, top_bit - bot_bit + 1) &
             ~MAKE_64BIT_MASK(55, 1);
         result = ptr ^ (pac & xor_mask);
+        if (cpu_isar_feature(aa64_fpac_combine, cpu)
+                || (cpu_isar_feature(aa64_fpac, cpu) && !is_combined)) {
+            int fpac_top = param.tbi ? 55 : 64;
+            uint64_t fpac_mask = MAKE_64BIT_MASK(bot_bit, fpac_top - bot_bit);
+            test = (result ^ sextract64(result, 55, 1)) & fpac_mask;
+            if (unlikely(test)) {
+                pauth_fail_exception(env, data, keynumber, ra);
+            }
+        }
     } else {
         test = (pac ^ ptr) & ~MAKE_64BIT_MASK(55, 1);
         if (unlikely(extract64(test, bot_bit, top_bit - bot_bit))) {
-- 
2.25.1