Re: [PATCH v2 2/2] m68k: Fix interrupt stack frames for 68000

From: Daniel Palmer <daniel@0x0f.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: gerg@linux-m68k.org, fthain@linux-m68k.org,
	 linux-m68k@lists.linux-m68k.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] m68k: Fix interrupt stack frames for 68000
Date: Tue, 9 Jan 2024 23:09:53 +0900	[thread overview]
Message-ID: <CAFr9PXn9wqbxToGDkSenW3XTCMPinUg1a9fHrUDQVhRKC6s5TA@mail.gmail.com> (raw)
In-Reply-To: <CAMuHMdX44A6+BNByuvbCC2gcM5vAipbaGAK7L8Vh8q3tMynBbQ@mail.gmail.com>

Hi All,

Sorry for the spam..

On Mon, 8 Jan 2024 at 18:56, Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> I think it would be better to use the classic m68k stack frame.
> That would pave the way for building a single nommu kernel for
> MC680[012346]0 that runs on e.g. any Amiga.
> MC68000 and Coldfire are incompatible anyway.

While looking at how to do this I realised that the addql #2,%sp in
RESTORE_ALL in entry.h will now break the stack frames for those fancy
68010+ users.
So that needs to be #ifdef'd to make it only compile for 68000. I saw
an error email from the next build stuff so I guess the change has
been queued somewhere? If so I should send a fix..
I'm not sure how to actually make that generic without patching the
code at runtime (remove the 68000 specific bit, reserve enough extra
space to rewrite the code..) but it's a macro so not so simple.

Anyhow, and more importantly, it seems like there is another issue in
68000/entry.S that breaks syscalls (especially vfork). After fixing
that I now have a working nommu 68000 system. I'll send a fix for that
too.

Cheers,

Daniel