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DEC: Limit PMAX memory probing to R3k systems

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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>
This commit is contained in:
Maciej W. Rozycki 2022-03-04 20:16:23 +00:00 committed by Thomas Bogendoerfer
parent 97bf0395c2
commit 244eae91a9
2 changed files with 6 additions and 11 deletions
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2
arch/mips/dec/prom/Makefile
View File

@ -6,4 +6,4 @@
lib-y += init.o memory.o cmdline.o identify.o console.o
lib-$(CONFIG_32BIT) += locore.o
lib-$(CONFIG_CPU_R3000) += locore.o

15
arch/mips/include/asm/dec/prom.h
View File

@ -43,16 +43,11 @@
*/
#define REX_PROM_MAGIC 0x30464354
#ifdef CONFIG_64BIT
#define prom_is_rex(magic) 1 /* KN04 and KN05 are REX PROMs. */
#else /* !CONFIG_64BIT */
#define prom_is_rex(magic) ((magic) == REX_PROM_MAGIC)
#endif /* !CONFIG_64BIT */
/* KN04 and KN05 are REX PROMs, so only do the check for R3k systems. */
static inline bool prom_is_rex(u32 magic)
{
return !IS_ENABLED(CONFIG_CPU_R3000) || magic == REX_PROM_MAGIC;
}
/*
* 3MIN/MAXINE PROM entry points for DS5000/1xx's, DS5000/xx's and