From: Brad Boyer <flar@allandria.com>
To: Michael Schmitz <schmitzmic@gmail.com>
Cc: Andreas Schwab <schwab@linux-m68k.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
geert@linux-m68k.org, linux-arch@vger.kernel.org,
linux-m68k@lists.linux-m68k.org, torvalds@linux-foundation.org
Subject: Re: [PATCH v4 0/3] m68k: Improved switch stack handling
Date: Sun, 25 Jul 2021 03:12:53 -0700 [thread overview]
Message-ID: <20210725101253.GA6096@allandria.com> (raw)
In-Reply-To: <db43bef1-7938-4fc1-853d-c20d66521329@gmail.com>
On Sun, Jul 25, 2021 at 07:44:11PM +1200, Michael Schmitz wrote:
> Am 25.07.2021 um 00:05 schrieb Andreas Schwab:
> >On Jul 24 2021, Michael Schmitz wrote:
> >
> >>According to my understanding, you can't get a F-line exception on
> >>68040.
> >
> >The F-line exception vector is used for all FPU illegal and
> >unimplemented insns.
>
> Thanks - now from my reading of the fpsp040 code (which has mislead me in
> the past), it would seem that operations like sin() and exp() ought to raise
> that exception then. I don't see that in ARAnyM.
Yes, according to the 68040 user's manual, unimplemented and illegal F-line
instructions trigger the standard F-line exception vector (11) but have
separate stack frame formats so the fpsp040 code gets some extra data.
The CPU does a bunch of the prep work so that part doesn't need to be
emulated in software.
The ARAnyM docs appear to claim a strange combination that wouldn't
exist in hardware by implementing a full 68882 instead of the limited
subset found on a real 68040. Strangely, that might have been easier to
implement. However, it would also completely bypass any use of fpsp040.
Brad Boyer
flar@allandria.com
next prev parent reply other threads:[~2021-07-25 10:13 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-23 0:21 [PATCH v4 0/3] m68k: Improved switch stack handling Michael Schmitz
2021-06-23 0:21 ` [PATCH v4 1/3] m68k: save extra registers on more syscall entry points Michael Schmitz
2021-06-23 0:21 ` [PATCH v4 2/3] m68k: correctly handle IO worker stack frame set-up Michael Schmitz
2021-06-23 0:21 ` [PATCH v4 3/3] m68k: track syscalls being traced with shallow user context stack Michael Schmitz
2021-07-25 10:05 ` Geert Uytterhoeven
2021-07-25 20:48 ` Michael Schmitz
2021-07-25 21:00 ` Linus Torvalds
2021-07-26 14:27 ` Greg Ungerer
2021-07-15 13:29 ` [PATCH v4 0/3] m68k: Improved switch stack handling Eric W. Biederman
2021-07-15 23:10 ` Michael Schmitz
2021-07-17 5:38 ` Michael Schmitz
2021-07-17 18:52 ` Eric W. Biederman
2021-07-17 20:09 ` Michael Schmitz
2021-07-17 23:04 ` Michael Schmitz
2021-07-18 10:47 ` Andreas Schwab
2021-07-18 19:47 ` Michael Schmitz
2021-07-18 20:59 ` Brad Boyer
2021-07-19 3:15 ` Michael Schmitz
2021-07-20 20:32 ` Eric W. Biederman
2021-07-20 22:16 ` Michael Schmitz
2021-07-22 14:49 ` Eric W. Biederman
2021-07-23 4:23 ` Michael Schmitz
2021-07-23 22:31 ` Eric W. Biederman
2021-07-23 23:52 ` Michael Schmitz
2021-07-24 12:05 ` Andreas Schwab
2021-07-25 7:44 ` Michael Schmitz
2021-07-25 10:12 ` Brad Boyer [this message]
2021-07-26 2:00 ` Michael Schmitz
2021-07-26 19:36 ` [RFC][PATCH] signal/m68k: Use force_sigsegv(SIGSEGV) in fpsp040_die Eric W. Biederman
2021-07-26 20:13 ` Andreas Schwab
2021-07-26 20:29 ` Eric W. Biederman
2021-07-26 21:25 ` Andreas Schwab
2021-07-26 20:29 ` Michael Schmitz
2021-07-26 21:08 ` [PATCH] " Eric W. Biederman
2021-08-25 15:56 ` Eric W. Biederman
2021-08-26 12:15 ` Geert Uytterhoeven
2021-07-25 11:53 ` [PATCH v4 0/3] m68k: Improved switch stack handling Andreas Schwab
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