target/arm: Move do_coproc_insn() syndrome calculation earlier

Rearrange the code in do_coproc_insn() so that we calculate the
syndrome value for a potential trap early; we're about to add a
second check that wants this value earlier than where it is currently
determined.

(Specifically, a trap to EL2 because of HSTR_EL2 should take
priority over an UNDEF to EL1, even when the UNDEF is because
the register does not exist at all or because its ri->access
bits non-configurably fail the access. So the check we put in
for HSTR_EL2 trapping at EL1 (which needs the syndrome) is
going to have to be done before the check "is the ARMCPRegInfo
pointer NULL".)

This commit is just code motion; the change to HSTR_EL2
handling that will use the 'syndrome' variable is in a
subsequent commit.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Fuad Tabba <tabba@google.com>
Message-id: 20230130182459.3309057-5-peter.maydell@linaro.org
Message-id: 20230127175507.2895013-5-peter.maydell@linaro.org

1 files changed, 41 insertions, 42 deletions

diff --git a/target/arm/translate.c b/target/arm/translate.c
index 365e02fb0b..9252a464a1 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -4718,6 +4718,47 @@ static void do_coproc_insn(DisasContext *s, int cpnum, int is64,
     const ARMCPRegInfo *ri = get_arm_cp_reginfo(s->cp_regs, key);
     TCGv_ptr tcg_ri = NULL;
     bool need_exit_tb;
+    uint32_t syndrome;
+
+    /*
+     * Note that since we are an implementation which takes an
+     * exception on a trapped conditional instruction only if the
+     * instruction passes its condition code check, we can take
+     * advantage of the clause in the ARM ARM that allows us to set
+     * the COND field in the instruction to 0xE in all cases.
+     * We could fish the actual condition out of the insn (ARM)
+     * or the condexec bits (Thumb) but it isn't necessary.
+     */
+    switch (cpnum) {
+    case 14:
+        if (is64) {
+            syndrome = syn_cp14_rrt_trap(1, 0xe, opc1, crm, rt, rt2,
+                                         isread, false);
+        } else {
+            syndrome = syn_cp14_rt_trap(1, 0xe, opc1, opc2, crn, crm,
+                                        rt, isread, false);
+        }
+        break;
+    case 15:
+        if (is64) {
+            syndrome = syn_cp15_rrt_trap(1, 0xe, opc1, crm, rt, rt2,
+                                         isread, false);
+        } else {
+            syndrome = syn_cp15_rt_trap(1, 0xe, opc1, opc2, crn, crm,
+                                        rt, isread, false);
+        }
+        break;
+    default:
+        /*
+         * ARMv8 defines that only coprocessors 14 and 15 exist,
+         * so this can only happen if this is an ARMv7 or earlier CPU,
+         * in which case the syndrome information won't actually be
+         * guest visible.
+         */
+        assert(!arm_dc_feature(s, ARM_FEATURE_V8));
+        syndrome = syn_uncategorized();
+        break;
+    }
 
     if (!ri) {
         /*
@@ -4755,48 +4796,6 @@ static void do_coproc_insn(DisasContext *s, int cpnum, int is64,
          * Note that on XScale all cp0..c13 registers do an access check
          * call in order to handle c15_cpar.
          */
-        uint32_t syndrome;
-
-        /*
-         * Note that since we are an implementation which takes an
-         * exception on a trapped conditional instruction only if the
-         * instruction passes its condition code check, we can take
-         * advantage of the clause in the ARM ARM that allows us to set
-         * the COND field in the instruction to 0xE in all cases.
-         * We could fish the actual condition out of the insn (ARM)
-         * or the condexec bits (Thumb) but it isn't necessary.
-         */
-        switch (cpnum) {
-        case 14:
-            if (is64) {
-                syndrome = syn_cp14_rrt_trap(1, 0xe, opc1, crm, rt, rt2,
-                                             isread, false);
-            } else {
-                syndrome = syn_cp14_rt_trap(1, 0xe, opc1, opc2, crn, crm,
-                                            rt, isread, false);
-            }
-            break;
-        case 15:
-            if (is64) {
-                syndrome = syn_cp15_rrt_trap(1, 0xe, opc1, crm, rt, rt2,
-                                             isread, false);
-            } else {
-                syndrome = syn_cp15_rt_trap(1, 0xe, opc1, opc2, crn, crm,
-                                            rt, isread, false);
-            }
-            break;
-        default:
-            /*
-             * ARMv8 defines that only coprocessors 14 and 15 exist,
-             * so this can only happen if this is an ARMv7 or earlier CPU,
-             * in which case the syndrome information won't actually be
-             * guest visible.
-             */
-            assert(!arm_dc_feature(s, ARM_FEATURE_V8));
-            syndrome = syn_uncategorized();
-            break;
-        }
-
         gen_set_condexec(s);
         gen_update_pc(s, 0);
         tcg_ri = tcg_temp_new_ptr();