]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
microblaze: Lockdep support
authorMichal Simek <monstr@monstr.eu>
Thu, 10 Dec 2009 11:07:02 +0000 (12:07 +0100)
committerMichal Simek <monstr@monstr.eu>
Mon, 14 Dec 2009 07:40:09 +0000 (08:40 +0100)
commitbf2d809668907c69b554459764b36584e4d57e4a
tree8f3e16925a34645ffd14e6d171937b37a06fba41
parent519e9f417388ba055b7604db5f4f492f7c84f427
microblaze: Lockdep support

Microblaze needs to do lock_init very soon because MMU init calls lock functions.

Here is the explanation from Peter Zijlstra why we have to enable
__ARCH_WANTS_INTERRUPTS_ON_CTSW.

"So we schedule while holding rq->lock (for obvious reasons), but since
lockdep tracks held locks per tasks, we need to transfer the held state
from the prev to the next task. We do this by explicity calling
spin_release(&rq->lock) in context_switch() right before switch_to(),
and calling spin_acquire(&rq->lock) in
finish_task_switch()->finish_lock_switch().

Now, for some reason lockdep thinks that interrupts got enabled over the
context switch (git grep __ARCH_WANTS_INTERRUPTS_ON_CTSW arch/microblaze
doesn't seem to turn up anything).

Clearly trying to acquire the rq->lock with interrupts enabled is a bad
idea and lockdep warns you about this."

Signed-off-by: Michal Simek <monstr@monstr.eu>
arch/microblaze/Kconfig
arch/microblaze/include/asm/system.h
arch/microblaze/kernel/setup.c