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From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH] ARM: new architecture for Energy Micro's EFM32 Cortex-M3 SoCs
Date: Mon, 16 Jan 2012 19:06:37 +0000	[thread overview]
Message-ID: <20120116190637.GE32049@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20120116181002.GC12267@arm.com>

On Mon, Jan 16, 2012 at 06:10:02PM +0000, Catalin Marinas wrote:
> On Mon, Jan 16, 2012 at 05:40:39PM +0000, Russell King - ARM Linux wrote:
> > The VFP stuff - adding 'clean' which is kernel state to the _user_
> > _exported_ VFP hardware structure is a bad idea.  So this needlessly
> > causes a variation in the kernels userspace API.  Please find somewhere
> > else to keep kernel internal state.  (As that patch comes from Catalin,
> > then that comment is directed to Catalin.)
> 
> Are you sure we export vfp_hard_struct to user? That's a kernel-only
> structure (and it's not by any means stable, given the number of
> #ifdef's it has). I would also argue that 'clean' is a hardware state
> (inferred from the exception return value).

Actually, looking at arch/arm/kernel/ptrace.c, we only export the
fpregs and fpscr, so this should be fine.

Still, I don't see why we need this 'clean' state, when normal VFP
doesn't need it.  Maybe you could explain why it's necessary?

  reply	other threads:[~2012-01-16 19:06 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-12-21 15:13 [RFC PATCH] ARM: new architecture for Energy Micro's EFM32 Cortex-M3 SoCs Uwe Kleine-König
2011-12-21 15:48 ` Jamie Iles
2011-12-21 16:44   ` Uwe Kleine-König
2011-12-21 19:56   ` Russell King - ARM Linux
2011-12-21 20:09     ` Jamie Iles
2011-12-21 20:36     ` Nicolas Pitre
2011-12-21 16:34 ` Arnd Bergmann
2011-12-21 19:54   ` Russell King - ARM Linux
2011-12-21 17:31 ` Ohad Ben-Cohen
2012-01-16 16:29   ` Uwe Kleine-König
2012-01-16 16:59     ` Ohad Ben-Cohen
2012-01-16 17:40     ` Russell King - ARM Linux
2012-01-16 18:10       ` Catalin Marinas
2012-01-16 19:06         ` Russell King - ARM Linux [this message]
2012-01-17 11:32           ` Catalin Marinas
2012-01-17 10:17       ` Uwe Kleine-König

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