drm2: do not try to return a value from a void function

lint complained:
vmalloc.h(79): error: void function vfree cannot return value [213]

No functional change.

linux: Use kmem directly for Linux kmalloc.

Take advantage of this to do LOCKDEBUG_MEM_CHECK at the point of
kfree_rcu rather than in the RCU GC thread.

Side-load <linux/mm.h> in a few places.

Stub vmap purge notifiers.

Define Linux array_size function and expose via vmalloc.h.

Linux vfree accepts NULL as noop. Match semantics.

From mrg@.

Implement kvfree by free(9); assume kmalloc/vmalloc use malloc(9).

Use uvm_km_alloc(kernel_map) and pmap_kenter, not uvm_pagermapin.

XXX pullup

Another round of nouveau whack-a-mole.

Make it build and boot on my test machines.

Screen blanks on boot on the Ivy Bridge system with

DRM error in cpt_serr_int_handler: PCH transcoder A FIFO underrun

But after that everything is OK

Make it build and boot on my test machines.

Screen blanks on boot on the Ivy Bridge system with

DRM error in cpt_serr_int_handler: PCH transcoder A FIFO underrun

But after that everything is OK. Appears to be an upstream problem.
To investigate...

I think there's a cache flushing issue somewhere -- there are little
display artefacts on my T60.

show more ...

Merge riastradh-drm2 to HEAD.