Messages in this thread | | | Date | Wed, 12 Feb 2020 17:38:00 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 0/7] microblaze: Define SMP safe operations |
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On Wed, Feb 12, 2020 at 05:08:52PM +0100, Peter Zijlstra wrote: > On Wed, Feb 12, 2020 at 04:42:22PM +0100, Michal Simek wrote: > > > Microblaze has 32bit exclusive load/store instructions which should be used > > instead of irq enable/disable. For more information take a look at > > https://www.xilinx.com/support/documentation/sw_manuals/xilinx2019_2/ug984-vivado-microblaze-ref.pdf > > starting from page 25. > > > arch/microblaze/include/asm/Kbuild | 1 - > > arch/microblaze/include/asm/atomic.h | 265 ++++++++++++++++++- > > arch/microblaze/include/asm/bitops.h | 189 +++++++++++++ > > arch/microblaze/include/asm/cmpxchg.h | 87 ++++++ > > arch/microblaze/include/asm/cpuinfo.h | 2 +- > > arch/microblaze/include/asm/pgtable.h | 19 +- > > arch/microblaze/include/asm/spinlock.h | 240 +++++++++++++++++ > > arch/microblaze/include/asm/spinlock_types.h | 25 ++ > > arch/microblaze/kernel/cpu/cache.c | 154 ++++++----- > > arch/microblaze/kernel/cpu/cpuinfo.c | 38 ++- > > arch/microblaze/kernel/cpu/mb.c | 207 ++++++++------- > > arch/microblaze/kernel/timer.c | 2 +- > > arch/microblaze/mm/consistent.c | 8 +- > > 13 files changed, 1040 insertions(+), 197 deletions(-) > > create mode 100644 arch/microblaze/include/asm/bitops.h > > create mode 100644 arch/microblaze/include/asm/spinlock.h > > create mode 100644 arch/microblaze/include/asm/spinlock_types.h > > I'm missing asm/barrier.h > > Also that PDF (thanks for that!), seems light on memory ordering > details. > > Your comment: > > +/* > + * clear_bit doesn't imply a memory barrier > + */ > > worries me, because that would imply your ll/sc does not impose order, > but then you also don't have any explicit barriers in your locking > primitives or atomics where required. > > In the PDF I only find MBAR; is that what smp_mb() ends up being?
Bah, I'm sure I did patches at some point that made asm-generic/barrier.h #error if you didn't define at least one memory barrier on CONFIG_SMP, but it seems that all got lost somewhere.
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