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From: Finn Thain <fthain@linux-m68k.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-m68k@lists.linux-m68k.org,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Greg Ungerer <gerg@linux-m68k.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC][CFT] signal handling fixes
Date: Thu, 16 Sep 2021 19:03:15 +1000 (AEST)	[thread overview]
Message-ID: <89b7f0e5-21a5-5828-1eb8-5119fb8e2d58@linux-m68k.org> (raw)
In-Reply-To: <YP2c1xk9LJ0zE3KW@zeniv-ca.linux.org.uk>

On Sun, 25 Jul 2021, Al Viro wrote:

> ...
> 
> PS:  FWIW, ifdefs in arch/m68k/kernel/signal.c are wrong - it's not !MMU 
> vs. coldfire/MMU vs. classic/MMU.  It's actually 68000 vs. coldfire vs. 
> everything else.  These days it's nearly correct, but only because on 
> MMU variants of coldfire we never see exception stack frames with type 
> other than 4 - it's controlled by alignment of kernel stack pointer on 
> those, and it's under the kernel control, so it's always 32bit-aligned.  
> It used to be more serious back when we had 68360 support - that's !MMU 
> and exception stack frames are like those on 68020, unless I'm 
> misreading their manual...
> 

I don't claim to understand this code but CPU32 cores appear to be 
unsupported on either #ifdef branch: the MMU branch due to CACR and CAAR 
used in push_cache(), and the !MMU branch due to frame format $4 used in 
adjust_format().

The CPU32 Reference Manual appendix says these chips only supports control 
registers SFC, DFC, VBR and stack frame formats $0, $2, $C. 
https://www.nxp.com/files-static/microcontrollers/doc/ref_manual/CPU32RM.pdf

  parent reply	other threads:[~2021-09-16  9:03 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-25 17:18 Al Viro
2021-07-25 17:19 ` [PATCH 1/3] m68k: handle arrivals of multiple signals correctly Al Viro
2021-09-15 22:08   ` Michael Schmitz
2021-07-25 17:19 ` [PATCH 2/3] m68k: update ->thread.esp0 before calling syscall_trace() in ret_from_signal Al Viro
2021-09-15 22:19   ` Michael Schmitz
2021-07-25 17:20 ` [PATCH 3/3] m68k: leave stack mangling to asm wrapper of sigreturn() Al Viro
2021-09-15 23:35   ` Michael Schmitz
2021-09-16  0:19     ` Al Viro
2021-09-16  0:53       ` Michael Schmitz
2021-09-16  3:21         ` Al Viro
2021-09-16  5:02           ` Michael Schmitz
2021-09-16 16:14             ` Al Viro
2021-07-27 10:21 ` [RFC][CFT] signal handling fixes Finn Thain
2021-07-27 14:42   ` Al Viro
2021-07-28  1:23     ` Finn Thain
2021-08-11  1:42     ` Finn Thain
2021-09-16  9:03 ` Finn Thain [this message]
2021-09-23 14:43   ` Geert Uytterhoeven
2021-09-23 14:45 ` Geert Uytterhoeven

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