x86: Rewrite 64-bit syscall code

This is kind of like the 32-bit and compat code, except that I preserved the fast path this time. I was unable to measure any significant performance change on my laptop in the fast path.

Changes from v1:
- Various tidying up.
- Remove duplicate tables (folded in, so the fastpath table isn't in this set).
- Rebased to 4.5-rc1
- Remove enter_from_user_mode stuff -- let's get the basics in first.

Andy Lutomirski (10):
selftests/x86: Extend Makefile to allow 64-bit-only tests selftests/x86: Add check_initial_reg_state
x86/syscalls: Refactor syscalltbl.sh
x86/syscalls: Remove __SYSCALL_COMMON and __SYSCALL_X32 x86/syscalls: Move compat syscall entry handling into syscalltbl.sh x86/syscalls: Add syscall entry qualifiers
x86/entry/64: Always run ptregs-using syscalls on the slow path x86/entry/64: Call all native slow-path syscalls with full pt-regs x86/entry/64: Stop using int_ret_from_sys_call in ret_from_fork x86/entry/64: Migrate the 64-bit syscall slow path to C

 arch/x86/entry/common.c                            |  26 ++
 arch/x86/entry/entry_64.S                          | 271 +++++++--------------
 arch/x86/entry/syscall_32.c                        |  10 +-
 arch/x86/entry/syscall_64.c                        |  13 +-
 arch/x86/entry/syscalls/syscall_64.tbl             |  18 +-
 arch/x86/entry/syscalls/syscalltbl.sh              |  58 ++++-
 arch/x86/kernel/asm-offsets_32.c                   |   2 +-
 arch/x86/kernel/asm-offsets_64.c                   |  10 +-
 arch/x86/um/sys_call_table_32.c                    |   4 +-
 arch/x86/um/sys_call_table_64.c                    |   7 +-
 arch/x86/um/user-offsets.c                         |   6 +-
 tools/testing/selftests/x86/Makefile               |  14 +-
 .../selftests/x86/check_initial_reg_state.c        | 109 +++++++++
 13 files changed, 317 insertions(+), 231 deletions(-)
 create mode 100644 tools/testing/selftests/x86/check_initial_reg_state.c

2.5.0