DEC: Limit PMAX memory probing to R3k systems
authorMaciej W. Rozycki <macro@orcam.me.uk>
Fri, 4 Mar 2022 20:16:23 +0000 (20:16 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 20 Apr 2022 07:08:12 +0000 (09:08 +0200)
commitba12400ed8b90bbdc1579efceba8cb67361ace60
treec9f5547c331bf487e31294f18b32d70edf8357cf
parent1c01f607228829b12481e62ad7ce61d249b466b1
DEC: Limit PMAX memory probing to R3k systems

commit 244eae91a94c6dab82b3232967d10eeb9dfa21c6 upstream.

Recent tightening of the opcode table in binutils so as to consistently
disallow the assembly or disassembly of CP0 instructions not supported
by the processor architecture chosen has caused a regression like below:

arch/mips/dec/prom/locore.S: Assembler messages:
arch/mips/dec/prom/locore.S:29: Error: opcode not supported on this processor: r4600 (mips3) `rfe'

in a piece of code used to probe for memory with PMAX DECstation models,
which have non-REX firmware.  Those computers always have an R2000 CPU
and consequently the exception handler used in memory probing uses the
RFE instruction, which those processors use.

While adding 64-bit support this code was correctly excluded for 64-bit
configurations, however it should have also been excluded for irrelevant
32-bit configurations.  Do this now then, and only enable PMAX memory
probing for R3k systems.

Reported-by: Jan-Benedict Glaw <jbglaw@lug-owl.de>
Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org # v2.6.12+
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/mips/dec/prom/Makefile
arch/mips/include/asm/dec/prom.h