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target/arm: Don't decode insns in the XScale/iWMMXt space as cp insns

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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.

Backports e4d51ac6921dc861bfb3d20e4c7dcf345840a9da
This commit is contained in:
Peter Maydell 2021-03-03 20:17:09 -05:00 committed by Lioncash
parent 09fd12e5f2
commit 68f645dd4f
1 changed files with 7 additions and 0 deletions
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7
qemu/target/arm/translate.c
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@ -5362,7 +5362,14 @@ 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;