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SubjectRe: [PATCH] ARM: pxa: fix building with clang
On Sat, Dec 17, 2022, at 21:45, Robert Jarzmik wrote:
> Arnd Bergmann <> writes:
>> From: Arnd Bergmann <>
>> 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 ?

According to

"MRRC is available in ARMv6 and above, and E variants of ARMv5
excluding xP variants". I'm not entire sure what "xP variants"
means, but we do build for ARMv5E, so I think this is actually


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