* Re: [PATCH] ARM: pxa: fix building with clang [not found] <20221215160747.2173998-1-arnd@kernel.org> @ 2022-12-17 20:45 ` Robert Jarzmik 2022-12-18 11:00 ` Arnd Bergmann 0 siblings, 1 reply; 3+ messages in thread From: Robert Jarzmik @ 2022-12-17 20:45 UTC (permalink / raw) To: Arnd Bergmann Cc: Daniel Mack, Haojian Zhuang, Robert Jarzmik, soc, Arnd Bergmann, Russell King, Nathan Chancellor, Nick Desaulniers, Tom Rix, linux-arm-kernel, linux-kernel, llvm Arnd Bergmann <arnd@kernel.org> writes: > From: Arnd Bergmann <arnd@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 ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] ARM: pxa: fix building with clang 2022-12-17 20:45 ` [PATCH] ARM: pxa: fix building with clang Robert Jarzmik @ 2022-12-18 11:00 ` Arnd Bergmann 2022-12-18 11:11 ` Robert Jarzmik 0 siblings, 1 reply; 3+ messages in thread From: Arnd Bergmann @ 2022-12-18 11:00 UTC (permalink / raw) To: Robert Jarzmik, Arnd Bergmann Cc: Daniel Mack, Haojian Zhuang, soc, Russell King, Nathan Chancellor, Nick Desaulniers, Tom Rix, linux-arm-kernel, linux-kernel, llvm On Sat, Dec 17, 2022, at 21:45, Robert Jarzmik wrote: > Arnd Bergmann <arnd@kernel.org> writes: > >> From: Arnd Bergmann <arnd@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 ? According to https://developer.arm.com/documentation/dui0231/b/arm-instruction-reference/coprocessor-instructions/mrrc-and-mrrc2?lang=en "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 correct. Arnd ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] ARM: pxa: fix building with clang 2022-12-18 11:00 ` Arnd Bergmann @ 2022-12-18 11:11 ` Robert Jarzmik 0 siblings, 0 replies; 3+ messages in thread From: Robert Jarzmik @ 2022-12-18 11:11 UTC (permalink / raw) To: Arnd Bergmann Cc: Robert Jarzmik, Arnd Bergmann, Daniel Mack, Haojian Zhuang, soc, Russell King, Nathan Chancellor, Nick Desaulniers, Tom Rix, linux-arm-kernel, linux-kernel, llvm "Arnd Bergmann" <arnd@arndb.de> writes: > "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 > correct. Ah yes, and XScale is ARMv5TE. Acked-by: Robert Jarzmik <robert.jarzmik@free.fr> Cheers. -- Robert ^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-12-17 20:45 ` [PATCH] ARM: pxa: fix building with clang Robert Jarzmik
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2022-12-18 11:11 ` Robert Jarzmik
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