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-rw-r--r--target/arm/translate-a64.c28
1 files changed, 26 insertions, 2 deletions
diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index 6a27234a5c..176a3c83ba 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -1795,6 +1795,30 @@ static void gen_set_nzcv(TCGv_i64 tcg_rt)
tcg_temp_free_i32(nzcv);
}
+static void gen_sysreg_undef(DisasContext *s, bool isread,
+ uint8_t op0, uint8_t op1, uint8_t op2,
+ uint8_t crn, uint8_t crm, uint8_t rt)
+{
+ /*
+ * Generate code to emit an UNDEF with correct syndrome
+ * information for a failed system register access.
+ * This is EC_UNCATEGORIZED (ie a standard UNDEF) in most cases,
+ * but if FEAT_IDST is implemented then read accesses to registers
+ * in the feature ID space are reported with the EC_SYSTEMREGISTERTRAP
+ * syndrome.
+ */
+ uint32_t syndrome;
+
+ if (isread && dc_isar_feature(aa64_ids, s) &&
+ arm_cpreg_encoding_in_idspace(op0, op1, op2, crn, crm)) {
+ syndrome = syn_aa64_sysregtrap(op0, op1, op2, crn, crm, rt, isread);
+ } else {
+ syndrome = syn_uncategorized();
+ }
+ gen_exception_insn(s, s->pc_curr, EXCP_UDEF, syndrome,
+ default_exception_el(s));
+}
+
/* MRS - move from system register
* MSR (register) - move to system register
* SYS
@@ -1820,13 +1844,13 @@ static void handle_sys(DisasContext *s, uint32_t insn, bool isread,
qemu_log_mask(LOG_UNIMP, "%s access to unsupported AArch64 "
"system register op0:%d op1:%d crn:%d crm:%d op2:%d\n",
isread ? "read" : "write", op0, op1, crn, crm, op2);
- unallocated_encoding(s);
+ gen_sysreg_undef(s, isread, op0, op1, op2, crn, crm, rt);
return;
}
/* Check access permissions */
if (!cp_access_ok(s->current_el, ri, isread)) {
- unallocated_encoding(s);
+ gen_sysreg_undef(s, isread, op0, op1, op2, crn, crm, rt);
return;
}