Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile

* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  arch/tile: don't validate CROSS_COMPILE needlessly
  arch/tile: export only COMMAND_LINE_SIZE to userspace.
  arch/tile: rename ARCH_KMALLOC_MINALIGN to ARCH_DMA_MINALIGN
  arch/tile: Rename the hweight() implementations to __arch_hweight()
  arch/tile: extend syscall ABI to set r1 on return as well.
  arch/tile: Various cleanups.
  arch/tile: support backtracing on TILE-Gx
  arch/tile: Fix a couple of issues with the COMPAT code for TILE-Gx.
  arch/tile: Use separate, better minsec values for clocksource and sched_clock.
  arch/tile: correct a bug in freeing bootmem by VA for the optional second initrd.
  arch: tile: mm: pgtable.c: Removed duplicated #include
  arch: tile: kernel/proc.c Removed duplicated #include
  Add fanotify syscalls to <asm-generic/unistd.h>.
  arch/tile: support new kunmap_atomic() naming convention.
  tile: remove unused ISA_DMA_THRESHOLD define

Conflicts in arch/tile/configs/tile_defconfig (pick the mainline version
with the reduced defconfig).

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/tile/mm/fault.c b/arch/tile/mm/fault.c
index 0011f06b4fe2..704f3e8a4385 100644
--- a/arch/tile/mm/fault.c
+++ b/arch/tile/mm/fault.c
@@ -567,6 +567,14 @@ do_sigbus:
  * since that might indicate we have not yet squirreled the SPR
  * contents away and can thus safely take a recursive interrupt.
  * Accordingly, the hypervisor passes us the PC via SYSTEM_SAVE_1_2.
+ *
+ * Note that this routine is called before homecache_tlb_defer_enter(),
+ * which means that we can properly unlock any atomics that might
+ * be used there (good), but also means we must be very sensitive
+ * to not touch any data structures that might be located in memory
+ * that could migrate, as we could be entering the kernel on a dataplane
+ * cpu that has been deferring kernel TLB updates.  This means, for
+ * example, that we can't migrate init_mm or its pgd.
  */
 struct intvec_state do_page_fault_ics(struct pt_regs *regs, int fault_num,
                                       unsigned long address,