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SubjectRe: [PATCH] compiler.h: avoid escaped section names
On Tue, Sep 29, 2020 at 12:43:18PM -0700, Nick Desaulniers wrote:
> The stringification operator, `#`, in the preprocessor escapes strings.
> For example, `# "foo"` becomes `"\"foo\""`. GCC and Clang differ in how
> they treat section names that contain \".
>
> The portable solution is to not use a string literal with the
> preprocessor stringification operator.
>
> In this case, since __section unconditionally uses the stringification
> operator, we actually want the more verbose
> __attribute__((__section__())).
>
> Link: https://bugs.llvm.org/show_bug.cgi?id=42950
> Fixes: commit e04462fb82f8 ("Compiler Attributes: remove uses of __attribute__ from compiler.h")
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
> include/linux/compiler.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/compiler.h b/include/linux/compiler.h
> index 92ef163a7479..ac45f6d40d39 100644
> --- a/include/linux/compiler.h
> +++ b/include/linux/compiler.h
> @@ -155,7 +155,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
> extern typeof(sym) sym; \
> static const unsigned long __kentry_##sym \
> __used \
> - __section("___kentry" "+" #sym ) \
> + __attribute__((__section__("___kentry+" #sym))) \
> = (unsigned long)&sym;
> #endif
>
> --
> 2.28.0.709.gb0816b6eb0-goog
>

There was this previous mini-thread:
https://lore.kernel.org/lkml/20200629205448.GA1474367@rani.riverdale.lan/
and this older one:
https://lore.kernel.org/lkml/20190904181740.GA19688@gmail.com/

Just for my own curiosity: how does KENTRY actually get used? grep
doesn't show any hits, and the thread from 2019 was actually going to
drop it if I read it right, and also just remove stringification from
the __section macro.

There are still other instances that need to be fixed, right?

Thanks.

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