target/arm: Implement FEAT_FPAC and FEAT_FPACCOMBINE

Signed-off-by: Aaron Lindsay <aaron@os.amperecomputing.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20230829232335.965414-10-richard.henderson@linaro.org
Message-Id: <20230609172324.982888-8-aaron@os.amperecomputing.com>
[rth: Simplify fpac comparison, reusing cmp_mask]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 17 insertions, 1 deletions

diff --git a/target/arm/tcg/pauth_helper.c b/target/arm/tcg/pauth_helper.c
index c05c5b30ff..4da2962ad5 100644
--- a/target/arm/tcg/pauth_helper.c
+++ b/target/arm/tcg/pauth_helper.c
@@ -396,6 +396,14 @@ static uint64_t pauth_original_ptr(uint64_t ptr, ARMVAParameters param)
     }
 }
 
+static G_NORETURN
+void pauth_fail_exception(CPUARMState *env, bool data,
+                          int keynumber, uintptr_t ra)
+{
+    raise_exception_ra(env, EXCP_UDEF, syn_pacfail(data, keynumber),
+                       exception_target_el(env), 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)
@@ -416,7 +424,15 @@ static uint64_t pauth_auth(CPUARMState *env, uint64_t ptr, uint64_t modifier,
     cmp_mask &= ~MAKE_64BIT_MASK(55, 1);
 
     if (pauth_feature >= PauthFeat_2) {
-        return ptr ^ (pac & cmp_mask);
+        ARMPauthFeature fault_feature =
+            is_combined ? PauthFeat_FPACCOMBINED : PauthFeat_FPAC;
+        uint64_t result = ptr ^ (pac & cmp_mask);
+
+        if (pauth_feature >= fault_feature
+            && ((result ^ sextract64(result, 55, 1)) & cmp_mask)) {
+            pauth_fail_exception(env, data, keynumber, ra);
+        }
+        return result;
     }
 
     if ((pac ^ ptr) & cmp_mask) {