linux-kernel - Re: [PATCH v5 07/20] x86/kexec: Invoke copy of relocate

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Message-ID: <ca9a3dfaf9859319c350b06314ebdd276e1a0e08.camel@infradead.org>
Date: Mon, 16 Dec 2024 08:13:35 +0000
From: David Woodhouse <dwmw2@...radead.org>
To: Nathan Chancellor <nathan@...nel.org>
Cc: kexec@...ts.infradead.org, Thomas Gleixner <tglx@...utronix.de>, Ingo
 Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, Dave Hansen
 <dave.hansen@...ux.intel.com>, x86@...nel.org, "H. Peter Anvin"
 <hpa@...or.com>,  "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
 Kai Huang <kai.huang@...el.com>, Nikolay Borisov <nik.borisov@...e.com>,
 linux-kernel@...r.kernel.org, Simon Horman <horms@...nel.org>, Dave Young
 <dyoung@...hat.com>, Peter Zijlstra <peterz@...radead.org>,
 jpoimboe@...nel.org, bsz@...zon.de
Subject: Re: [PATCH v5 07/20] x86/kexec: Invoke copy of relocate_kernel()
 instead of the original

On Sun, 2024-12-15 at 22:49 -0700, Nathan Chancellor wrote:
> On Sun, Dec 15, 2024 at 10:09:57AM +0000, David Woodhouse wrote:
> > On Sat, 2024-12-14 at 16:08 -0700, Nathan Chancellor wrote:
> > > 
> > > I guess this seems somewhat unavoidable because control_page is just a
> > > 'void *', perhaps machine_kexec() should just be marked as __nocfi? This
> > > diff resolves that issue for me.
> > 
> > The patch below seems to work too. I already wanted to deal with the
> 
> Can confirm, thanks for the quick fix. With your fix for the first issue
> I reported, the fix I sent for LTO, and this patch below, I can kexec on
> a CFI and LTO enabled kernel without any issues.
> 

Thank you for testing.  Which is the LTO one? Is it in my tree yet or
have I missed it?
https://git.infradead.org/?p=users/dwmw2/linux.git;a=shortlog;h=refs/heads/kexec-debug

(The fix we're discussing here isn't there yet; it still needs
polishing)

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