linux-kernel - Re: [PATCH v5 2/2] x86/jailhouse: Only enable platform UARTs if available

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Message-ID: <20191007165958.GE24289@zn.tnic>
Date:   Mon, 7 Oct 2019 18:59:58 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Ralf Ramsauer <ralf.ramsauer@...-regensburg.de>
Cc:     Jan Kiszka <jan.kiszka@...mens.com>, x86@...nel.org,
        jailhouse-dev@...glegroups.com, linux-kernel@...r.kernel.org,
        Ingo Molnar <mingo@...hat.com>,
        "H . Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH v5 2/2] x86/jailhouse: Only enable platform UARTs if
 available

On Mon, Oct 07, 2019 at 06:44:39PM +0200, Ralf Ramsauer wrote:
> Yep, jailhouse_serial_fixup can become __init, I didn't see that, but
> you're right, thanks. I'm curious, how did you find that?

CONFIG_SECTION_MISMATCH_WARN_ONLY=y

If that it off, it fails the build even:

WARNING: vmlinux.o(.text+0x4fdb0): Section mismatch in reference from the function jailhouse_serial_fixup() to the variable .init.data:can_use_brk_pgt
The function jailhouse_serial_fixup() references
the variable __initdata can_use_brk_pgt.
This is often because jailhouse_serial_fixup lacks a __initdata 
annotation or the annotation of can_use_brk_pgt is wrong.

FATAL: modpost: Section mismatches detected.
Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.
make[1]: *** [scripts/Makefile.modpost:66: __modpost] Error 1
make: *** [Makefile:1074: vmlinux] Error 2

Apparently we did that with:

47490ec141b9 ("modpost: Add flag -E for making section mismatches fatal")

> "We" didn't notice yet. :-)

LOL.

> BTW, we refers to the Jailhouse folks, but I will rewrite that.

Thanks.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette