[PATCH v2 0/3] io.h, logic_pio: Allow barriers for inX() and outX() be overridden

John Garry
2020-03-27T16:10:42Z

Since commits a7851aa54c0c ("io: change outX() to have their own IO
barrier overrides") and 87fe2d543f81 ("io: change inX() to have their own
IO barrier overrides"), the outX() and inX() functions have memory
barriers which can be overridden per-arch.

However, under CONFIG_INDIRECT_PIO, logic_pio defines its own version of
inX() and outX(), which still use readb et al. For these, the barrier
after a raw read is weaker than it otherwise would be.

This series generates consistent behaviour for logic_pio, by defining
generic _inX() and _outX() in asm-generic/io.h, and using those in
logic_pio. Generic _inX() and _outX() have per-arch overrideable
barriers.

The topic was discussed there originally:
https://lore.kernel.org/lkml/2e80d7bc-32a0-cc40-00a9-8a383a1966c2@huawei.com/

A small tidy-up patch is included.

I hope that series can go through the arm-soc tree, as with other recent
logic_pio changes.

Hi Arnd,

I added your tag, but please let me know if you have any issue with the
updated change in patch #1.

cheers

- Differences to v1
- fix x86 clang build by adding extra build swicth for _{in,out}X
- added Arnd's RB tag

John Garry (3):
io: Provide _inX() and _outX()
logic_pio: Improve macro argument name
logic_pio: Use _inX() and _outX()

include/asm-generic/io.h | 64 +++++++++++++++++++++++++++++++++---------------
lib/logic_pio.c | 22 ++++++++---------
2 files changed, 55 insertions(+), 31 deletions(-)

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2.16.4