ARM: fix PTRACE_SETVFPREGS on SMP systems
authorRussell King <rmk+kernel@armlinux.org.uk>
Mon, 30 May 2016 22:14:56 +0000 (23:14 +0100)
committerRussell King <rmk+kernel@armlinux.org.uk>
Thu, 2 Jun 2016 13:18:56 +0000 (14:18 +0100)
commite2dfb4b880146bfd4b6aa8e138c0205407cebbaf
treec85508f8da9fe817b0cf78e3647050be4e9612a9
parentec953b70f368330e806a94df6fe2dd1d72176b2d
ARM: fix PTRACE_SETVFPREGS on SMP systems

PTRACE_SETVFPREGS fails to properly mark the VFP register set to be
reloaded, because it undoes one of the effects of vfp_flush_hwstate().

Specifically vfp_flush_hwstate() sets thread->vfpstate.hard.cpu to
an invalid CPU number, but vfp_set() overwrites this with the original
CPU number, thereby rendering the hardware state as apparently "valid",
even though the software state is more recent.

Fix this by reverting the previous change.

Cc: <stable@vger.kernel.org>
Fixes: 8130b9d7b9d8 ("ARM: 7308/1: vfp: flush thread hwstate before copying ptrace registers")
Acked-by: Will Deacon <will.deacon@arm.com>
Tested-by: Simon Marchi <simon.marchi@ericsson.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
arch/arm/kernel/ptrace.c