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From: David Laight <David.Laight@ACULAB.COM>
To: 'Arnd Bergmann' <arnd@kernel.org>,
	Sam Ravnborg <sam@ravnborg.org>,
	"David S . Miller" <davem@davemloft.net>,
	Andreas Larsson <andreas@gaisler.com>
Cc: Helge Deller <deller@gmx.de>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Alan Stern <stern@rowland.harvard.edu>,
	Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
	"sparclinux@vger.kernel.org" <sparclinux@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	"linux-fbdev@vger.kernel.org" <linux-fbdev@vger.kernel.org>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>,
	"linux-sound@vger.kernel.org" <linux-sound@vger.kernel.org>
Subject: RE: [PATCH 00/27] sparc32: sunset sun4m and sun4d
Date: Wed, 20 Dec 2023 09:34:09 +0000	[thread overview]
Message-ID: <9c4479a3d194450593d541ae02ad288a@AcuMS.aculab.com> (raw)
In-Reply-To: <01ea8c41-88cd-4123-95c7-391640845fc3@app.fastmail.com>

From: Arnd Bergmann
> Sent: 20 December 2023 08:37
> 
> On Tue, Dec 19, 2023, at 22:03, Sam Ravnborg via B4 Relay wrote:
> > TODO before this can be applied:
> > - Ack from davem - as he is the principal sparc maintainer
> > - Tested-by: preferably on a target or QEMU (see above)
> >   I expect bugs as there are some involved changes!
> >
> > Ideas for the future
> > - Apply the most relevant downstream Gaisler patches
> >   - The ones introducing CAS should have preference as we then
> >     can drop the cmpxchg emulation
> 
> One note about the CAS -- as far as I can tell, the absence
> of the futex() syscall on sparc32 kernels means that no glibc
> from the past decade can work correctly as it now requires futex
> for its internal locking, though it does work on sparc64 kernels
> in compat32 mode as well as the LEON3 kernel that adds futex
> support.

Does the glibc mutex 'fast path' also require a CAS instruction?

Presumably having CAS also removes the 'really horrid (tm)' code
required to make all the bitmap operations atomic?

Seems a shame to lose old sparc32 support when (I think) the sun3
in my cupboard would still work - if only it had a working psu.
(The 110/220V switch wasn't connected and the FET wasn't rated
for 450V. UK mains can be 240+10% if you are near a substation.)

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)


  parent reply	other threads:[~2023-12-20  9:34 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-19 22:03 [PATCH 00/27] sparc32: sunset sun4m and sun4d Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 01/27] sparc32: Update defconfig to LEON SMP Sam Ravnborg via B4 Relay
2023-12-19 22:23   ` Arnd Bergmann
2023-12-20  6:43     ` Sam Ravnborg
2023-12-20  8:37       ` Arnd Bergmann
2023-12-19 22:03 ` [PATCH 02/27] sparc32: Drop sun4m/sun4d support from head_32.S Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 03/27] sparc32: Drop floppy support Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 04/27] sparc32: Drop sun4m specific led driver Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 05/27] sparc32: Drop sun specific power management drivers Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 06/27] sparc32: Drop auxio support Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 07/27] sparc32: Drop run-time patching of ipi trap Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 08/27] sparc32: Drop patching of interrupt vector Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 09/27] sparc32: Drop sun4m/sun4d specific irq handling Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 10/27] sparc32: Drop sun4d/sun4m smp support Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 11/27] sparc32: Drop pcic support Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 12/27] sparc32: Drop mbus support Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 13/27] sparc32: Drop unused function __get_{phys,iospace} Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 14/27] sparc32: Drop unused mmu models Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 15/27] sparc32: Drop check for sparc_model Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 16/27] sparc32: Drop use of sparc_config Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 17/27] sparc32: Drop run-time patching of ASI instructions Sam Ravnborg via B4 Relay
2024-02-16 17:12   ` Andreas Larsson
2024-02-17 11:59     ` Sam Ravnborg
2023-12-19 22:03 ` [PATCH 18/27] sparc32: Drop support for 7 register windows Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 19/27] sparc32: Drop additional sun4d bits Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 20/27] sparc32: Drop unused prom ranges support Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 21/27] sparc32: Drop unused iommu support Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 22/27] sparc32: Drop sun4m irq support Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 23/27] sparc32: Drop unused trampoline code Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 24/27] sparc32: Drop config SPARC_LEON Sam Ravnborg via B4 Relay
2023-12-20  5:52   ` Greg Kroah-Hartman
2023-12-19 22:03 ` [PATCH 25/27] sparc32: Drop sbus support Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 26/27] sbus: char: Drop now unused uctrl driver Sam Ravnborg via B4 Relay
2023-12-19 22:03 ` [PATCH 27/27] fbdev/p9100: Drop now unused driver p9100 Sam Ravnborg via B4 Relay
2024-01-02  8:26   ` Thomas Zimmermann
2024-01-02 16:31     ` Sam Ravnborg
2023-12-20  8:36 ` [PATCH 00/27] sparc32: sunset sun4m and sun4d Arnd Bergmann
2023-12-20  9:28   ` John Paul Adrian Glaubitz
2023-12-20  9:34   ` David Laight [this message]
2023-12-20  9:51     ` Arnd Bergmann
2023-12-20  9:54   ` John Paul Adrian Glaubitz
2023-12-20 10:47     ` Arnd Bergmann
2023-12-20 11:30       ` Mark Cave-Ayland
2023-12-20 15:22         ` Sam Ravnborg
2023-12-20 17:25           ` John Paul Adrian Glaubitz
2023-12-22 15:27             ` Andreas Larsson
2023-12-20 14:42 ` Kjetil Oftedal
2024-02-04 19:21 ` Sam Ravnborg
2024-02-05  5:12   ` John Paul Adrian Glaubitz

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