Re: [PATCH 18/46] entry, lto: Mark raw_irqentry_exit_cond_resched() as __visible

Thomas Gleixner
2022-11-16T23:30:45Z

On Mon, Nov 14 2022 at 12:43, Jiri Slaby wrote:
> Symbols referenced from assembler (either directly or e.f. from

from assembler? I'm not aware that the assembler references anything.

Also what does e.f. mean? Did you want to write e.g.?

> DEFINE_STATIC_KEY()) need to be global and visible in gcc LTO because
> they could end up in a different object file than the assembler. This

than the assembler? Are we shipping the assembler in an object file?

> can lead to linker errors without this patch.

git grep -i 'this patch' Documentation/process/

> So mark raw_irqentry_exit_cond_resched() as __visible.

And all that tells me what? I know what you want to say, but it's not
there.

Symbols in different compilation units which are referenced from
assembly code either directly or indirectly, e.g. from
DEFINE_STATIC_KEY(), must be marked visible for GCC based LTO builds.

Add the missing __visible annotation to raw_irqentry_exit_cond_resched().

See?

There is no 'global' because it's obvious that a symbol in a different
compilation unit must be global to be resolvable. It's also obvious that
code in different compilation units ends up in different object files.

So stating that it's a 'must' to have such symbols marked visible is
good enough for an argument because that tells the reader that this is a
mandatory requirement for an GCC based LTO build.

No?

Thanks,

tglx