powerpc: Enable Prefixed Instructions

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Prefix instructions have their own FSCR bit which needs to enabled via
a CPU feature. The kernel will save the FSCR for problem state but it
needs to be enabled initially.

If prefixed instructions are made unavailable by the [H]FSCR, attempting
to use them will cause a facility unavailable exception. Add "PREFIX" to
the facility_strings[].

Currently there are no prefixed instructions that are actually emulated
by emulate_instruction() within facility_unavailable_exception().
However, when caused by a prefixed instructions the SRR1 PREFIXED bit is
set. Prepare for dealing with emulated prefixed instructions by checking
for this bit.

Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Link: https://lore.kernel.org/r/20200506034050.24806-22-jniethe5@gmail.com

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Alistair Popple 2020-05-06 13:40:41 +10:00 • committed by Michael Ellerman

parent 0b582db549

commit 2aa6195e43

2 changed files with 4 additions and 0 deletions

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arch/powerpc/include/asm/reg.h

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1

arch/powerpc/kernel/traps.c

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