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SubjectRe: [PATCH 4/5] ARM: use unified assembler in c files
Thanks for the reviews so far.

During some more testing I stumbled upon another issue:

On 07.02.2019 10:48, Stefan Agner wrote:
> Use unified assembler syntax (UAL) in inline assembler. Divided
> syntax is considered depricated. This will also allow to build
> the kernel using LLVM's integrated assembler.
>
> Signed-off-by: Stefan Agner <stefan@agner.ch>
> ---
> arch/arm/mm/copypage-v4mc.c | 2 +-
> arch/arm/mm/copypage-v4wb.c | 2 +-
> arch/arm/mm/copypage-v4wt.c | 2 +-
> 3 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/mm/copypage-v4mc.c b/arch/arm/mm/copypage-v4mc.c
> index b03202cddddb..b19c7ad1a6de 100644
> --- a/arch/arm/mm/copypage-v4mc.c
> +++ b/arch/arm/mm/copypage-v4mc.c
> @@ -56,7 +56,7 @@ static void mc_copy_user_page(void *from, void *to)
> ldmia %0!, {r2, r3, ip, lr} @ 4\n\
> subs %2, %2, #1 @ 1\n\
> stmia %1!, {r2, r3, ip, lr} @ 4\n\
> - ldmneia %0!, {r2, r3, ip, lr} @ 4\n\
> + ldmiane %0!, {r2, r3, ip, lr} @ 4\n\
> bne 1b @ "
> : "+&r" (from), "+&r" (to), "=&r" (tmp)
> : "2" (PAGE_SIZE / 64)
> diff --git a/arch/arm/mm/copypage-v4wb.c b/arch/arm/mm/copypage-v4wb.c
> index cd3e165afeed..6e3c9b69dd25 100644
> --- a/arch/arm/mm/copypage-v4wb.c
> +++ b/arch/arm/mm/copypage-v4wb.c
> @@ -38,7 +38,7 @@ static void v4wb_copy_user_page(void *kto, const void *kfrom)
> ldmia %1!, {r3, r4, ip, lr} @ 4\n\
> subs %2, %2, #1 @ 1\n\
> stmia %0!, {r3, r4, ip, lr} @ 4\n\
> - ldmneia %1!, {r3, r4, ip, lr} @ 4\n\
> + ldmiane %1!, {r3, r4, ip, lr} @ 4\n\
> bne 1b @ 1\n\
> mcr p15, 0, %1, c7, c10, 4 @ 1 drain WB"
> : "+&r" (kto), "+&r" (kfrom), "=&r" (tmp)
> diff --git a/arch/arm/mm/copypage-v4wt.c b/arch/arm/mm/copypage-v4wt.c
> index 8614572e1296..4a40fa1cbc2a 100644
> --- a/arch/arm/mm/copypage-v4wt.c
> +++ b/arch/arm/mm/copypage-v4wt.c
> @@ -34,7 +34,7 @@ static void v4wt_copy_user_page(void *kto, const void *kfrom)
> ldmia %1!, {r3, r4, ip, lr} @ 4\n\
> subs %2, %2, #1 @ 1\n\
> stmia %0!, {r3, r4, ip, lr} @ 4\n\
> - ldmneia %1!, {r3, r4, ip, lr} @ 4\n\
> + ldmiane %1!, {r3, r4, ip, lr} @ 4\n\
> bne 1b @ 1\n\
> mcr p15, 0, %2, c7, c7, 0 @ flush ID cache"
> : "+&r" (kto), "+&r" (kfrom), "=&r" (tmp)

When compiling with gcc, this leads to:

/tmp/ccrvA1wy.s: Assembler messages:
/tmp/ccrvA1wy.s:180: Error: bad instruction `ldmiane r0!,{r3,r4,ip,lr}'
make[1]: *** [scripts/Makefile.build:277: arch/arm/mm/copypage-v4wb.o]
Error 1
make: *** [Makefile:1042: arch/arm/mm] Error 2

Unfortunately, the gcc option -masm-syntax-unified which allows unified
syntax in inline assembly is broken (see also
https://lkml.org/lkml/2019/1/7/1320).

So this requires to sprinkle those inline assembly with ".syntax
unified" strings, similar to how I've done it in uaccess.h.

--
Stefan

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