MIPS: math-emu: Correct delay-slot exception propagation

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Restore EPC at the branch whose delay slot is emulated if the delay-slot
instruction signals.  This is so that code in `fpu_emulator_cop1Handler'
does not see EPC having advanced and mistakenly successfully resume
userland execution from the location at the branch target in that case.
Restoring EPC guarantees an immediate exit from the emulation loop and
if EPC hasn't advanced at all since entering the loop, also issuing the
signal reported by the delay-slot instruction.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9701/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

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Maciej W. Rozycki 2015-04-03 23:26:56 +01:00 • committed by Ralf Baechle

parent 2d83fea786

commit 9ab4471c9f

2 changed files with 30 additions and 6 deletions

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34

arch/mips/math-emu/cp1emu.c

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2

arch/mips/math-emu/dsemul.c

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