linux-kernel - Re: [PATCH] x86/vdso: drop implicit common-page-size linker flag

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Message-ID: <20181207101814.GA9385@zn.tnic>
Date:   Fri, 7 Dec 2018 11:18:14 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     ndesaulniers@...gle.com
Cc:     luto@...nel.org, Fangrui Song <maskray@...gle.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Andi Kleen <andi@...stfloor.org>,
        Dmitry Golovin <dima@...ovin.in>,
        Bill Wendling <morbo@...gle.com>, Rui Ueyama <ruiu@...gle.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86/vdso: drop implicit common-page-size linker flag

On Thu, Dec 06, 2018 at 11:12:31AM -0800, ndesaulniers@...gle.com wrote:
> These are implied by the target architecture and for x86_64 match the
> max-page-size. The default for non-NaCl x86_64 is 0x1000 (4096).
> 
> In bfd the common page size is defined as 0x1000 (4096) for non-NaCl

Sodium Chloride?

> x86_64 targets:
> 
> bfd/elf64-x86-64.c:
> 4998:#define ELF_COMMONPAGESIZE             0x1000
> 
> For gold, the common page size is defined as 0x1000 (4096) for non-NaCl
> x86_64 targets:
> 
> gold/x86_64.cc:
> 1413:  0x1000, // common_pagesize (overridable by -z common-page-size)
> 1442:  0x1000, // common_pagesize (overridable by -z common-page-size)
> 
> (ELF_COMMONPAGESIZE also defaults to ELF_MAXPAGESIZE when not set
> explicitly for a target architecture in bfd/elfxx-target.h, but that's
> not relevant for x86_64).
> 
> Because it's implied by the target architecture, it's of questionable
> use to implement in LLD.  This patch resolves one of the issues towards
> using LLD to link an x86_64 kernel.

LLD?

I can only guess what this commit message is about and have to look at
the patch itself and then look at the LD(1) man page and rhyme up what
it is aiming to do.

How about rewriting it for mere mortals?

Thx.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.