From: David Laight <David.Laight@ACULAB.COM>
To: 'Matthew Wilcox' <willy@infradead.org>
Cc: Greg Ungerer <gregungerer@westnet.com.au>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
"torvalds@linux-foundation.org" <torvalds@linux-foundation.org>,
Nicholas Piggin <npiggin@gmail.com>
Subject: RE: [PATCH 09/17] m68k: Implement xor_unlock_is_negative_byte
Date: Tue, 19 Sep 2023 14:35:25 +0000 [thread overview]
Message-ID: <cffc2a427ae74f62b07345ec9348e43e@AcuMS.aculab.com> (raw)
In-Reply-To: <ZQmvhC+pGWNs9R23@casper.infradead.org>
From: Matthew Wilcox <willy@infradead.org>
> Sent: 19 September 2023 15:26
>
> On Tue, Sep 19, 2023 at 01:23:08PM +0000, David Laight wrote:
> > > Well, that sucks. What do you suggest for Coldfire?
> >
> > Can you just do a 32bit xor ?
> > Unless you've got smp m68k I'd presume it is ok?
> > (And assuming you aren't falling off a page.)
>
> Patch welcome.
My 68020 book seems to be at work and I'm at home.
(The 286, 386 and cy7c600 (sparc 32) books don't help).
But if the code is trying to do *ptr ^= 0x80 and check the
sign flag then you just need to use eor.l with 0x80000000
on the same address.
All the 68k I used would do misaligned accesses.
Although they can fault mid-instruction on the microcode stack.
Any smp 68020 had to be certain to resume on the same cpu.
David
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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2023-09-19 14:35 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-15 18:36 [PATCH 00/17] Add folio_end_read Matthew Wilcox (Oracle)
2023-09-15 18:36 ` [PATCH 01/17] iomap: Hold state_lock over call to ifs_set_range_uptodate() Matthew Wilcox (Oracle)
2023-09-15 18:36 ` [PATCH 02/17] iomap: Protect read_bytes_pending with the state_lock Matthew Wilcox (Oracle)
2023-09-16 0:11 ` Linus Torvalds
2023-09-16 0:15 ` Linus Torvalds
2023-09-16 15:50 ` Matthew Wilcox
2023-09-15 18:36 ` [PATCH 03/17] mm: Add folio_end_read() Matthew Wilcox (Oracle)
2023-09-15 18:36 ` [PATCH 04/17] ext4: Use folio_end_read() Matthew Wilcox (Oracle)
2023-09-15 18:36 ` [PATCH 05/17] buffer: " Matthew Wilcox (Oracle)
2023-09-15 18:36 ` [PATCH 06/17] iomap: " Matthew Wilcox (Oracle)
2023-09-15 18:36 ` [PATCH 07/17] bitops: Add xor_unlock_is_negative_byte() Matthew Wilcox (Oracle)
2023-09-15 18:36 ` [PATCH 08/17] alpha: Implement xor_unlock_is_negative_byte Matthew Wilcox (Oracle)
2023-09-16 0:27 ` Linus Torvalds
2023-09-16 0:38 ` Matthew Wilcox
2023-09-16 2:01 ` Linus Torvalds
2023-09-16 2:14 ` Linus Torvalds
2023-09-16 15:59 ` Matthew Wilcox
2023-09-15 18:36 ` [PATCH 09/17] m68k: " Matthew Wilcox (Oracle)
2023-09-16 13:11 ` Greg Ungerer
2023-09-16 14:34 ` Matthew Wilcox
2023-09-18 14:37 ` Greg Ungerer
2023-09-20 7:45 ` Greg Ungerer
2023-09-20 16:58 ` Linus Torvalds
2023-09-19 13:23 ` David Laight
2023-09-19 14:26 ` Matthew Wilcox
2023-09-19 14:35 ` David Laight [this message]
2023-09-19 15:14 ` Matthew Wilcox
2023-09-19 15:22 ` David Laight
2023-09-19 15:47 ` Matthew Wilcox
2023-09-19 15:57 ` David Laight
2023-09-20 7:15 ` Greg Ungerer
2023-09-20 7:22 ` Greg Ungerer
2023-10-02 20:07 ` Matthew Wilcox
2023-10-03 14:14 ` Greg Ungerer
2023-10-03 20:07 ` Matthew Wilcox
2023-10-04 12:06 ` Greg Ungerer
2023-09-15 18:37 ` [PATCH 10/17] mips: " Matthew Wilcox (Oracle)
2023-09-15 18:37 ` [PATCH 11/17] powerpc: Implement arch_xor_unlock_is_negative_byte on 32-bit Matthew Wilcox (Oracle)
2023-09-15 18:37 ` [PATCH 12/17] riscv: Implement xor_unlock_is_negative_byte Matthew Wilcox (Oracle)
2023-09-15 18:37 ` [PATCH 13/17] s390: Implement arch_xor_unlock_is_negative_byte Matthew Wilcox (Oracle)
2023-09-15 18:37 ` [PATCH 14/17] mm: Delete checks for xor_unlock_is_negative_byte() Matthew Wilcox (Oracle)
2023-09-15 18:37 ` [PATCH 15/17] mm: Add folio_xor_flags_has_waiters() Matthew Wilcox (Oracle)
2023-09-15 18:37 ` [PATCH 16/17] mm: Make __end_folio_writeback() return void Matthew Wilcox (Oracle)
2023-09-15 18:37 ` [PATCH 17/17] mm: Use folio_xor_flags_has_waiters() in folio_end_writeback() Matthew Wilcox (Oracle)
2023-09-16 0:31 ` [PATCH 00/17] Add folio_end_read Linus Torvalds
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