[RFC PATCH v2 0/4] Enable strict percpu address space checks

[Uros Bizjak]

This patchset enables strict percpu address space checks via x86 named 
address space qualifiers. Percpu variables are declared in
__seg_gs/__seg_fs named AS and kept named AS qualified until they
are dereferenced via percpu accessor. This approach enables various
compiler checks for cross-namespace variable assignments.

Please note that sparse doesn't know anything about __typeof_unqual__()
operator, so the usage of __typeof_unqual__() breaks sparse checking.

Cc: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Nadav Amit <nadav.amit@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>

Uros Bizjak (4):
  percpu: Define pcpu_typeof()
  percpu: Assorted fixes found by strict percpu address space checks
  percpu: Repurpose __percpu tag as a named address space qualifier
  percpu/x86: Enable strict percpu checks via named AS qualifiers

 arch/x86/include/asm/percpu.h  | 53 ++++++++++++++++++++++++----------
 arch/x86/kernel/head64.c       |  3 +-
 drivers/base/devres.c          |  2 +-
 fs/aio.c                       |  2 +-
 include/asm-generic/percpu.h   | 41 +++++++++++++++++---------
 include/linux/cleanup.h        |  4 +--
 include/linux/compiler_types.h |  2 +-
 include/linux/part_stat.h      |  2 +-
 include/linux/percpu-defs.h    | 39 ++++++++++++++++++++-----
 include/linux/prandom.h        |  1 +
 init/Kconfig                   |  3 ++
 kernel/events/hw_breakpoint.c  |  4 +--
 kernel/locking/percpu-rwsem.c  |  2 +-
 kernel/workqueue.c             |  2 +-
 lib/percpu_counter.c           |  2 +-
 net/core/dev.c                 |  2 +-
 16 files changed, 115 insertions(+), 49 deletions(-)

-- 
2.46.0