target-mips: Don't stop on [d]mtc0 DESAVE/KScratch

Writing to the MIPS DESAVE register (and now the KScratch registers)
will stop translation, supposedly due to risk of execution mode
switches. However these registers are basically RW scratch registers
with no side effects so there is no risk of them triggering execution
mode changes.

Drop the bstate = BS_STOP for these registers for both mtc0 and dmtc0.

Backports commit cb539fd241900f51de7d21244f7a55422ad0d40a from qemu
This commit is contained in:
James Hogan 2018-03-04 01:25:18 -05:00 committed by Lioncash
parent 567bc68803
commit 987401c4d4
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GPG Key ID: 4E3C3CC1031BA9C7

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@ -6472,8 +6472,6 @@ static void gen_mtc0(DisasContext *ctx, TCGv arg, int reg, int sel)
default: default:
goto cp0_unimplemented; goto cp0_unimplemented;
} }
/* Stop translation as we may have switched the execution mode */
ctx->bstate = BS_STOP;
break; break;
default: default:
goto cp0_unimplemented; goto cp0_unimplemented;
@ -7798,8 +7796,6 @@ static void gen_dmtc0(DisasContext *ctx, TCGv arg, int reg, int sel)
default: default:
goto cp0_unimplemented; goto cp0_unimplemented;
} }
/* Stop translation as we may have switched the execution mode */
ctx->bstate = BS_STOP;
break; break;
default: default:
goto cp0_unimplemented; goto cp0_unimplemented;