linux-kernel - Re: [PATCH v2] objtool: fix objtool regression on x32 systems

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Date:   Wed, 18 May 2022 11:08:25 -0700
From:   Josh Poimboeuf <jpoimboe@...nel.org>
To:     Mikulas Patocka <mpatocka@...hat.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] objtool: fix objtool regression on x32 systems

On Wed, May 18, 2022 at 09:28:57AM -0400, Mikulas Patocka wrote:
> 
> 
> On Mon, 16 May 2022, Peter Zijlstra wrote:
> 
> > On Mon, May 16, 2022 at 11:56:21AM -0400, Mikulas Patocka wrote:
> > > 
> > > With this patch, the compiled kernel works. With kernels 5.17 or older, it 
> > > also works. I bisected it and the breakage is caused by the commit 
> > > 4abff6d48dbc.
> > 
> > Sure; but it works doesn't mean there aren't more latent issues. ILP32
> > hosted (cross) builds just aren't a thing I've ever considered. If we
> > really want to go support that then we should at least audit the whole
> > thing.
> > 
> > A quick look seems to suggest at least all the 'offset' fields should be
> > u64 or something. The only reason that works is because -mcmodel=kernel
> > keeps everything in the 2G range to make s32 immediates work. But it
> > isn't right.
> 
> There are many 'offset' variables and its hard to determine which should 
> be 64-bit. Would it be possible to commit this patch, so that kernel 5.18 
> can be compiled on x32 distributions? And you can do code refactoring in 
> the next merge window.

I believe Peter is going ahead with merging this for 5.18, and your v2
looks identical to what he already has here:

  https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/log/?h=objtool/urgent

-- 
Josh