Paul Walmsley 39141ddfb6 ARM: 7566/1: vfp: fix save and restore when running on pre-VFPv3 and CONFIG_VFPv3 set ... After commit 846a136881 ("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 5aaf254409 ("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 Måns to clarify the name of the HWCAP flag. Signed-off-by: Paul Walmsley <paul@pwsan.com> Cc: Tony Lindgren <tony@atomide.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Martin <dave.martin@linaro.org> Cc: Måns Rullgård <mans.rullgard@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>		2012-10-29 10:04:05 +00:00
..
Makefile	ARM: vfp: use -mfloat-abi=soft to build vfp	2011-10-01 21:08:55 +02:00
entry.S	ARM: Fix undefined instruction exception handling	2012-07-31 12:04:30 +01:00
vfp.h	[ARM] 5387/1: Add ptrace VFP support on ARM	2009-02-12 10:59:43 +00:00
vfpdouble.c	[ARM] vfp: fix fuitod/fsitod instructions	2008-01-10 17:07:08 +00:00
vfphw.S	Merge branch 'fixes' of git://git.linaro.org/people/rmk/linux-arm	2012-08-01 16:30:45 -07:00
vfpinstr.h	[ARM] 4583/1: ARMv7: Add VFPv3 support	2008-01-26 14:41:28 +00:00
vfpmodule.c	ARM: 7566/1: vfp: fix save and restore when running on pre-VFPv3 and CONFIG_VFPv3 set	2012-10-29 10:04:05 +00:00
vfpsingle.c	[ARM] Remove unnecessary asm/ptrace.h from VFP support code	2007-04-22 10:56:40 +01:00