[PATCH v4 0/9] kentry: A stable bugfix and a bunch of improvements

[Andy Lutomirski]

I noticed a little bug in fast compat syscalls.  I got a bit carried away
fixing it.  This renames the irqentry stuff to kentry, improves (IMNSHO)
the API, and adds lots of debugging.

It also tweaks the unwinder wrt ret_from_fork and rewrites ret_from_fork
in C.  I did this because the kentry work involved a small change to
ret_from_fork, and adjusting the asm is a mess.  So C it is.

Changes from v3: Get rid of arm64 special cases

Changes from v1 and v2: Complete rewrite

Andy Lutomirski (9):
  x86/dumpstack: Remove unnecessary range check fetching opcode bytes
  x86/kthread,dumpstack: Set task_pt_regs->cs.RPL=3 for kernel threads
  x86/entry: Convert ret_from_fork to C
  kentry: Simplify the common syscall API
  kentry: Remove enter_from/exit_to_user_mode()
  entry: Make CONFIG_DEBUG_ENTRY available outside x86
  kentry: Add debugging checks for proper kentry API usage
  kentry: Check that syscall entries and syscall exits match
  kentry: Verify kentry state in instrumentation_begin/end()

 arch/x86/Kconfig.debug           |  10 --
 arch/x86/entry/common.c          |  78 ++++++++++----
 arch/x86/entry/entry_32.S        |  51 ++-------
 arch/x86/entry/entry_64.S        |  33 ++----
 arch/x86/include/asm/switch_to.h |   2 +-
 arch/x86/kernel/dumpstack.c      |  10 +-
 arch/x86/kernel/process.c        |  15 ++-
 arch/x86/kernel/process_32.c     |   2 +-
 arch/x86/kernel/traps.c          |   4 +-
 arch/x86/kernel/unwind_orc.c     |   2 +-
 include/asm-generic/bug.h        |   8 +-
 include/linux/entry-common.h     | 127 +++--------------------
 include/linux/instrumentation.h  |  25 ++++-
 include/linux/sched.h            |   4 +
 init/init_task.c                 |   8 ++
 kernel/entry/common.c            | 173 ++++++++++++++++++++-----------
 lib/Kconfig.debug                |  11 ++
 17 files changed, 267 insertions(+), 296 deletions(-)

-- 
2.30.2