Messages in this thread | | | Date | Fri, 3 Apr 2020 15:24:58 -0700 | From | Nathan Chancellor <> | Subject | Re: [PATCH] elfnote: mark all .note sections SHF_ALLOC |
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On Fri, Apr 03, 2020 at 03:13:34PM -0700, 'Nick Desaulniers' via Clang Built Linux wrote: > dropping Jeremy; I got bounceback from the email address. Ping for review? > > On Wed, Mar 25, 2020 at 4:13 PM Nick Desaulniers > <ndesaulniers@google.com> wrote: > > > > ELFNOTE_START allows callers to specify flags for .pushsection assembler > > directives. All callsites but ELF_NOTE use "a" for SHF_ALLOC. For > > vdso's that explicitly use ELF_NOTE_START and BUILD_SALT, the same > > section is specified twice after preprocessing, once with "a" flag, once > > without. Example: > > > > .pushsection .note.Linux, "a", @note ; > > .pushsection .note.Linux, "", @note ; > > > > While GNU as allows this ordering, it warns for the opposite ordering, > > making these directives position dependent. We'd prefer not to precisely > > match this behavior in Clang's integrated assembler. Instead, the non > > __ASSEMBLY__ definition of ELF_NOTE uses > > __attribute__((section(".note.Linux"))) which is created with SHF_ALLOC, > > so let's make the __ASSEMBLY__ definition of ELF_NOTE consistent with C > > and just always use "a" flag. > > > > This allows Clang to assemble a working mainline (5.6) kernel via: > > $ make CC=clang AS=clang > > > > Link: https://github.com/ClangBuiltLinux/linux/issues/913 > > Cc: Jeremy Fitzhardinge <jeremy@xensource.com> > > Debugged-by: Ilie Halip <ilie.halip@gmail.com> > > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> > --- > > Ilie has further treewide cleanups: > > https://github.com/ihalip/linux/commits/elfnote > > This patch is the simplest to move us forwards. > > > > include/linux/elfnote.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/include/linux/elfnote.h b/include/linux/elfnote.h > > index 594d4e78654f..69b136e4dd2b 100644 > > --- a/include/linux/elfnote.h > > +++ b/include/linux/elfnote.h > > @@ -54,7 +54,7 @@ > > .popsection ; > > > > #define ELFNOTE(name, type, desc) \ > > - ELFNOTE_START(name, type, "") \ > > + ELFNOTE_START(name, type, "a") \ > > desc ; \ > > ELFNOTE_END > > > > -- > > 2.26.0.rc2.310.g2932bb562d-goog > > > > > -- > Thanks, > ~Nick Desaulniers
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