In commit cd8be50e58f63413c0 we converted the A32 coprocessor
insns to decodetree. This accidentally broke XScale/iWMMXt insns,
because it moved the handling of "cp insns which are handled
by looking up the cp register in the hashtable" from after the
call to the legacy disas_xscale_insn() decode to before it,
with the result that all XScale/iWMMXt insns now UNDEF.
Update valid_cp() so that it knows that on XScale cp 0 and 1
are not standard coprocessor instructions; this will cause
the decodetree trans_ functions to ignore them, so that
execution will correctly get through to the legacy decode again.
Cc: qemu-sta...@nongnu.org
Reported-by: Guenter Roeck <li...@roeck-us.net>
Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
Reviewed-by: Richard Henderson <richard.hender...@linaro.org>
Tested-by: Guenter Roeck <li...@roeck-us.net>
Message-id: 20210108195157.32067-1-peter.mayd...@linaro.org
---
target/arm/translate.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/target/arm/translate.c b/target/arm/translate.c
index f5acd32e76a..528b93dffa2 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -5282,7 +5282,14 @@ static bool valid_cp(DisasContext *s, int cp)
* only cp14 and cp15 are valid, and other values aren't considered
* to be in the coprocessor-instruction space at all. v8M still
* permits coprocessors 0..7.
+ * For XScale, we must not decode the XScale cp0, cp1 space as
+ * a standard coprocessor insn, because we want to fall through to
+ * the legacy disas_xscale_insn() decoder after decodetree is done.
*/
+ if (arm_dc_feature(s, ARM_FEATURE_XSCALE) && (cp == 0 || cp == 1)) {
+ return false;
+ }
+
if (arm_dc_feature(s, ARM_FEATURE_V8) &&
!arm_dc_feature(s, ARM_FEATURE_M)) {
return cp >= 14;
--
2.20.1
