linux-kernel - Re: 4.17.x won't boot due to "x86/boot/compressed/64: Handle 5-level paging boot if kernel is above 4G"

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Date:   Wed, 4 Jul 2018 16:21:53 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Benjamin Gilbert <bgilbert@...hat.com>
Cc:     Gabriel C <nix.or.die@...il.com>, linux-x86_64@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        "H. Peter Anvin" <hpa@...or.com>, X86 ML <x86@...nel.org>,
        bero@...dev.ch, Andi Kleen <ak@...ux.intel.com>
Subject: Re: 4.17.x won't boot due to "x86/boot/compressed/64: Handle 5-level
 paging boot if kernel is above 4G"

On Tue, Jul 03, 2018 at 11:10:27PM -0400, Benjamin Gilbert wrote:
> On Tue, Jul 03, 2018 at 05:21:50PM +0300, Kirill A. Shutemov wrote:
> > I don't know how to solve it. As far as I know we don't support compiling
> > kernel with LTO in mainline.
> > 
> > Any suggestions?
> > 
> > Benjamin, do you change LDFLAGS or CFLAGS when compiling the kernel?
> 
> We're using the standard build flags as far as I can tell.  In particular,
> we don't enable LTO, and I've verified that -flto isn't in the build logs.
> 
> Here's a sample image:
> 
> https://users.developer.core-os.net/bgilbert/4.17/vmlinuz-4.17.3-coreos
> https://users.developer.core-os.net/bgilbert/4.17/vmlinux-4.17.3-coreos
> https://users.developer.core-os.net/bgilbert/4.17/System.map

It's basically the same issue. We have immidiate load instead of
RIP-relative address load.

You can make the vmlinuz bootable with this binary patch:

echo -en "\x8d\x05\xa9\xa9\xff\xff" | dd of=vmlinuz-4.17.3-coreos seek=$((0x005d1fc1)) bs=1 conv=notrunc

Now we need to find out how linker gets it wrong.

Please, *after* complete build of the kernel with your toolchain do this:

touch arch/x86/boot/compressed/pgtable_64.c
make V=1

And share your build log.

-- 
 Kirill A. Shutemov