powerpc: Fix emulation of illegal instructions on PowerNV platform
authorPaul Mackerras <paulus@samba.org>
Fri, 14 Jun 2013 10:07:41 +0000 (20:07 +1000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 20 Jun 2013 19:01:33 +0000 (12:01 -0700)
commit5cf1b34ca312b3626201ab7bafe5dc884e028616
tree0c75cbea4f9a35552174392ca23a0e2c8418fc76
parenta1fb10e6d2ee287036139b4f4a75763ffbf9b70b
powerpc: Fix emulation of illegal instructions on PowerNV platform

commit bf593907f7236e95698a76b7c7a2bbf8b1165327 upstream.

Normally, the kernel emulates a few instructions that are unimplemented
on some processors (e.g. the old dcba instruction), or privileged (e.g.
mfpvr).  The emulation of unimplemented instructions is currently not
working on the PowerNV platform.  The reason is that on these machines,
unimplemented and illegal instructions cause a hypervisor emulation
assist interrupt, rather than a program interrupt as on older CPUs.
Our vector for the emulation assist interrupt just calls
program_check_exception() directly, without setting the bit in SRR1
that indicates an illegal instruction interrupt.  This fixes it by
making the emulation assist interrupt set that bit before calling
program_check_interrupt().  With this, old programs that use no-longer
implemented instructions such as dcba now work again.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/powerpc/kernel/exceptions-64s.S
arch/powerpc/kernel/traps.c