tree 45ecb27cc5e95c9ea936964d6f553ca04bdf859d
parent 655861e328cea83320190f4a57b3656ee952388c
author Tim Bird <tim.bird@am.sony.com> 1335995739 +0100
committer Russell King <rmk+kernel@arm.linux.org.uk> 1336222441 +0100

ARM: 7410/1: Add extra clobber registers for assembly in kernel_execve

The inline assembly in kernel_execve() uses r8 and r9.  Since this
code sequence does not return, it usually doesn't matter if the
register clobber list is accurate.  However, I saw a case where a
particular version of gcc used r8 as an intermediate for the value
eventually passed to r9.  Because r8 is used in the inline
assembly, and not mentioned in the clobber list, r9 was set
to an incorrect value.

This resulted in a kernel panic on execution of the first user-space
program in the system.  r9 is used in ret_to_user as the thread_info
pointer, and if it's wrong, bad things happen.

Cc: <stable@vger.kernel.org>
Signed-off-by: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>