[PATCH 0/2] arm64: Add support for CLOCK_MONOTONIC_RAW in clock_gettime() vDSO

Kevin Brodsky kevin.brodsky at arm.com
Mon May 9 05:36:59 PDT 2016


This small series adds support for CLOCK_MONOTONIC_RAW to
clock_gettime() (and clock_getres()) in the arm64 vDSO. This should make
calls to clock_gettime() with CLOCK_MONOTONIC_RAW just as fast as
CLOCK_MONOTONIC and such, instead of falling back to the significantly
slower syscall.

Given that gettimeofday.S is already quite difficult to understand, and
directly adding MONOTONIC_RAW support makes it even more so, the first
patch refactors it to make it simpler, and save a few instructions along
the way. The second patch actually adds support for MONOTONIC_RAW, which
is made quite easy by the refactoring.


Kevin Brodsky (2):
  arm64: Refactor vDSO time functions
  arm64: Add support for CLOCK_MONOTONIC_RAW in clock_gettime() vDSO

 arch/arm64/include/asm/vdso_datapage.h |   8 +-
 arch/arm64/kernel/asm-offsets.c        |   6 +-
 arch/arm64/kernel/vdso.c               |   8 +-
 arch/arm64/kernel/vdso/gettimeofday.S  | 317 ++++++++++++++++++++-------------
 4 files changed, 215 insertions(+), 124 deletions(-)


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