[PATCH v3 0/4] powerpc/64: copy_tofrom_user exception handling improvements

[Paul Mackerras]

This is a repost of a series that I posted back in 2016 but which was
never applied.  It aims to make the exception handling code in
__copy_tofrom_user_base clearer and easier to verify, and strengthens
the selftests for the user copy code to test all the paths and to test
the exception handling.  Finally it then fixes a deficiency in that
when copying to userspace we don't always copy quite as many bytes as
we could.

I have rebased this series on top of the powerpc next branch as of
today.

Paul.

 arch/powerpc/lib/copyuser_64.S                     | 585 +++++++++------------
 arch/powerpc/lib/copyuser_power7.S                 |  21 +-
 arch/powerpc/lib/memcpy_64.S                       |   9 +-
 arch/powerpc/lib/memcpy_power7.S                   |  22 +-
 .../testing/selftests/powerpc/copyloops/.gitignore |  17 +-
 tools/testing/selftests/powerpc/copyloops/Makefile |  44 +-
 .../selftests/powerpc/copyloops/asm/ppc_asm.h      |  44 +-
 .../powerpc/copyloops/copy_tofrom_user_reference.S |  24 +
 .../selftests/powerpc/copyloops/exc_validate.c     | 124 +++++
 tools/testing/selftests/powerpc/copyloops/stubs.S  |  19 +
 10 files changed, 516 insertions(+), 393 deletions(-)