On 18.03.2019 19:09, Nick Desaulniers wrote: > On Sun, Mar 17, 2019 at 4:05 PM Stefan Agner <[email protected]> wrote: >> >> Currently LLVM's integrated assembler does not recognize .w form >> of the pld instructions (LLVM Bug 40972 [0]): >> >> ./arch/arm/include/asm/processor.h:133:5: error: invalid instruction >> "pldw.w\t%a0 \n" >> ^ >> <inline asm>:2:1: note: instantiated into assembly here >> pldw.w [r0] >> ^ >> 1 error generated. >> >> The W macro for generating wide instructions when targeting Thumb-2 >> is not strictly required for the preload data instructions (pld, pldw) >> since they are only available as wide instructions. The GNU assembler >> works with or without the .w appended when compiling an Thumb-2 kernel. >> >> Drop the macro to work around LLVM Bug 40972 issue. >> >> [0] https://bugs.llvm.org/show_bug.cgi?id=40972 >> >> Signed-off-by: Stefan Agner <[email protected]> > > Thanks for the bug report and patch. > Reviewed-by: Nick Desaulniers <[email protected]> > > Just curious, there are only 3 other expansion sites of this macro. > Are any of those problematic? Looks like nop.w, sev.w and b.w? >
All three sites are in inline assembly, and I did a bunch of successful Thumb2 builds using the integrated assembler, so I think all those sites have been assembled by LLVM successfully. Also confirmed those three instructions with the reproducer example from the LLVM bug above. -- Stefan >> --- >> Changes in v2: >> - Reword commit message to reflect the fact that this is a work around >> for LLVM. >> >> arch/arm/include/asm/processor.h | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/arch/arm/include/asm/processor.h >> b/arch/arm/include/asm/processor.h >> index 57fe73ea0f72..5d06f75ffad4 100644 >> --- a/arch/arm/include/asm/processor.h >> +++ b/arch/arm/include/asm/processor.h >> @@ -135,8 +135,8 @@ static inline void prefetchw(const void *ptr) >> __asm__ __volatile__( >> ".arch_extension mp\n" >> __ALT_SMP_ASM( >> - WASM(pldw) "\t%a0", >> - WASM(pld) "\t%a0" >> + "pldw\t%a0", >> + "pld\t%a0" >> ) >> :: "p" (ptr)); >> } >> -- >> 2.21.0 >>
