Re: [PATCH 10/10] Add sample notification program [ver #3]

From: David Howells
Date: Thu Jun 06 2019 - 18:57:05 EST


Eugeniu Rosca <erosca@xxxxxxxxxxxxxx> wrote:

> How about arm64? Do you intend to enable cross-compilation?

There's no guarantee that a cross-compiler can actually build userspace apps,
though I haven't intended to encode anything against that in the Makefile.

> > + asm ("lfence" : : : "memory" );
> [..]
> > + asm("mfence" ::: "memory");
>
> FWIW, trying to cross-compile it returned:
>
> aarch64-linux-gnu-gcc -I../../usr/include -I../../include watch_test.c -o watch_test
> /tmp/ccDXYynm.s: Assembler messages:
> /tmp/ccDXYynm.s:471: Error: unknown mnemonic `lfence' -- `lfence'
> /tmp/ccDXYynm.s:568: Error: unknown mnemonic `mfence' -- `mfence'

Yeah. I need to use C-standard __atomic_* stuff.

David