Re: [PATCH] arm64: lse: fix LSE atomics with LLVM's integrated assembler

From: Sami Tolvanen
Date: Mon Oct 07 2019 - 17:24:33 EST


On Mon, Oct 7, 2019 at 1:28 PM 'Nick Desaulniers' via Clang Built
Linux <clang-built-linux@xxxxxxxxxxxxxxxx> wrote:
> I tried adding `.arch armv8-a+lse` directives to all of the inline asm:
> https://github.com/ClangBuiltLinux/linux/issues/573#issuecomment-535098996

Yes, I had a similar patch earlier. I feel like using a command line
parameter here is cleaner, but I'm fine with either solution.

> One thing to be careful about is that blankets the entire kernel in
> `+lse`, allowing LSE atomics to be selected at any point.

Is that a problem? The current code allows LSE instructions with gcc
in any file that includes <asm/lse.h>, which turns out to be quite a
few places.

Sami