clean up address limit helpers

[Christoph Hellwig]

Hi all,

in preparation for eventually phasing out direct use of set_fs(), this
series removes the segment_eq() arch helper that is only used to
implement or duplicate the uaccess_kernel() API, and then adds
descriptive helpers to force the kernel address limit.

Diffstat:
 arch/alpha/include/asm/uaccess.h      |    2 +-
 arch/arc/include/asm/segment.h        |    3 +--
 arch/arm/include/asm/uaccess.h        |    4 ++--
 arch/arm64/include/asm/uaccess.h      |    2 +-
 arch/arm64/kernel/sdei.c              |    2 +-
 arch/csky/include/asm/segment.h       |    2 +-
 arch/h8300/include/asm/segment.h      |    2 +-
 arch/ia64/include/asm/uaccess.h       |    2 +-
 arch/m68k/include/asm/segment.h       |    2 +-
 arch/m68k/include/asm/tlbflush.h      |   12 ++++++------
 arch/microblaze/include/asm/uaccess.h |    2 +-
 arch/mips/include/asm/uaccess.h       |    2 +-
 arch/mips/kernel/unaligned.c          |   27 +++++++++++++--------------
 arch/nds32/include/asm/uaccess.h      |    2 +-
 arch/nds32/kernel/process.c           |    2 +-
 arch/nds32/mm/alignment.c             |    7 +++----
 arch/nios2/include/asm/uaccess.h      |    2 +-
 arch/openrisc/include/asm/uaccess.h   |    2 +-
 arch/parisc/include/asm/uaccess.h     |    2 +-
 arch/powerpc/include/asm/uaccess.h    |    3 +--
 arch/riscv/include/asm/uaccess.h      |    6 +++---
 arch/s390/include/asm/uaccess.h       |    2 +-
 arch/sh/include/asm/segment.h         |    3 +--
 arch/sh/kernel/traps_32.c             |   18 ++++++++----------
 arch/sparc/include/asm/uaccess_32.h   |    2 +-
 arch/sparc/include/asm/uaccess_64.h   |    2 +-
 arch/x86/include/asm/uaccess.h        |    2 +-
 arch/xtensa/include/asm/uaccess.h     |    2 +-
 drivers/firmware/arm_sdei.c           |    5 ++---
 fs/exec.c                             |    7 ++++++-
 include/asm-generic/uaccess.h         |    4 ++--
 include/linux/syscalls.h              |    2 +-
 include/linux/uaccess.h               |   20 ++++++++++++++++++--
 kernel/events/callchain.c             |    5 ++---
 kernel/events/core.c                  |    5 ++---
 kernel/exit.c                         |    2 +-
 kernel/kthread.c                      |    5 ++---
 kernel/stacktrace.c                   |    5 ++---
 mm/maccess.c                          |   22 ++++++++++------------
 39 files changed, 105 insertions(+), 98 deletions(-)