From: tony@atomide•com (Tony Lindgren)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v3] ARM: vfp: fix save and restore when running on pre-VFPv3 and CONFIG_VFPv3 set
Date: Mon, 15 Oct 2012 10:53:18 -0700 [thread overview]
Message-ID: <20121015175317.GE15569@atomide.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1210150523190.15973@utopia.booyaka.com>
* Paul Walmsley <paul@pwsan•com> [121014 22:26]:
>
> After commit 846a136881b8f73c1f74250bf6acfaa309cab1f2 ("ARM: vfp: fix
> saving d16-d31 vfp registers on v6+ kernels"), the OMAP 2430SDP board
> started crashing during boot with omap2plus_defconfig:
>
> [ 3.875122] mmcblk0: mmc0:e624 SD04G 3.69 GiB
> [ 3.915954] mmcblk0: p1
> [ 4.086639] Internal error: Oops - undefined instruction: 0 [#1] SMP ARM
> [ 4.093719] Modules linked in:
> [ 4.096954] CPU: 0 Not tainted (3.6.0-02232-g759e00b #570)
> [ 4.103149] PC is at vfp_reload_hw+0x1c/0x44
> [ 4.107666] LR is at __und_usr_fault_32+0x0/0x8
>
> It turns out that the context save/restore fix unmasked a latent bug
> in commit 5aaf254409f8d58229107b59507a8235b715a960 ("ARM: 6203/1: Make
> VFPv3 usable on ARMv6"). When CONFIG_VFPv3 is set, but the kernel is
> booted on a pre-VFPv3 core, the code attempts to save and restore the
> d16-d31 VFP registers. These are only present on non-D16 VFPv3+, so
> this results in an undefined instruction exception. The code didn't
> crash before commit 846a136 because the save and restore code was
> only touching d0-d15, present on all VFP.
>
> Fix by implementing a request from Russell King to add a new HWCAP
> flag that affirmatively indicates the presence of the d16-d31
> registers:
>
> http://marc.info/?l=linux-arm-kernel&m=135013547905283&w=2
>
> and some feedback from M?ns to clarify the name of the HWCAP flag.
>
> Signed-off-by: Paul Walmsley <paul@pwsan•com>
> Cc: Tony Lindgren <tony@atomide•com>
> Cc: Russell King <rmk+kernel@arm•linux.org.uk>
> Cc: Catalin Marinas <catalin.marinas@arm•com>
> Cc: Dave Martin <dave.martin@linaro•org>
> Cc: M?ns Rullg?rd <mans.rullgard@linaro•org>
This fixes the error above on my 2430sdp:
Tested-by: Tony Lindgren <tony@atomide•com>
next prev parent reply other threads:[~2012-10-15 17:53 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-13 4:46 [PATCH] ARM: vfp: fix save and restore when running on pre-VFPv3 and CONFIG_VFPv3 set Paul Walmsley
2012-10-13 9:02 ` Russell King - ARM Linux
2012-10-13 10:50 ` Måns Rullgård
2012-10-13 13:36 ` Russell King - ARM Linux
2012-10-15 1:58 ` Paul Walmsley
2012-10-15 2:39 ` Mans Rullgard
2012-10-15 5:24 ` [PATCH v3] " Paul Walmsley
2012-10-15 17:53 ` Tony Lindgren [this message]
2012-10-16 17:13 ` Jon Hunter
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