linux-kernel - Re: [PATCH 3/9] efi/x86: Move efi stub globals from .bss to .data

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Message-ID: <CAMj1kXFhtK=FRDKBE5OtenNEtpK=kVwyo+0nqJZ_K80RmtYxEg@mail.gmail.com>
Date:   Fri, 10 Apr 2020 10:20:42 +0200
From:   Ard Biesheuvel <ardb@...nel.org>
To:     Arvind Sankar <nivedita@...m.mit.edu>
Cc:     Brian Gerst <brgerst@...il.com>,
        linux-efi <linux-efi@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Arnd Bergmann <arnd@...db.de>, Borislav Petkov <bp@...e.de>,
        Colin Ian King <colin.king@...onical.com>,
        Gary Lin <glin@...e.com>, Jiri Slaby <jslaby@...e.cz>,
        Sergey Shatunov <me@...k.pw>, Takashi Iwai <tiwai@...e.de>
Subject: Re: [PATCH 3/9] efi/x86: Move efi stub globals from .bss to .data

On Thu, 9 Apr 2020 at 23:08, Arvind Sankar <nivedita@...m.mit.edu> wrote:
>
> On Thu, Apr 09, 2020 at 04:53:07PM -0400, Brian Gerst wrote:
> > > Can we use the -fno-zero-initialized-in-bss compiler flag instead of
> > > explicitly marking global variables?
> >
> > Scratch that.  Apparently it only works when a variable is explicitly
> > initialized to zero.
> >
> > --
> > Brian Gerst
>
> Right, there doesn't seem to be a compiler option to turn off the use of
> .bss altogether.

Yeah. I'll try to come up with a way to consolidate this a bit across
architectures (which is a bit easier now that all of the EFI stub C
code lives in the same place). It is probably easiest to use a section
renaming trick similar to the one I added for ARM (as Arvind suggested
as well, IIRC), and get rid of the per-symbol annotations altogether.