Re: [PATCH] ARM: pxa: fix building with clang

From: Robert Jarzmik
Date: Sat Dec 17 2022 - 15:59:32 EST



Arnd Bergmann <arnd@xxxxxxxxxx> writes:

From: Arnd Bergmann <arnd@xxxxxxxx>

The integrated assembler in clang does not understand the xscale
specific mra/mar instructions:

arch/arm/mach-pxa/pxa27x.c:136:15: error: unsupported architectural extension: xscale
asm volatile(".arch_extension xscale\n\t"
arch/arm/mach-pxa/pxa27x.c:136:40: error: invalid instruction, did you mean: mcr, mla, mrc, mrs, msr?
mra r2, r3, acc0

Since these are coprocessor features, the same can be expressed using
mrrc/mcrr, so use that for builds with IAS.
Ok Arnd, but "mrrc" is an ARMv6 instruction if I'm not mistaken.
Yet PXA27X is an ARMv5 XScale instruction set IP.

Is that patch correct therefore, or is it just to make clang happy even if it's
not correct ?

Cheers.

--
Robert