[PATCH] ARM: pxa: fix building with clang

Robert Jarzmik robert.jarzmik at free.fr
Sat Dec 17 12:45:41 PST 2022


Arnd Bergmann <arnd at kernel.org> writes:

> From: Arnd Bergmann <arnd at arndb.de>
>
> 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



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