Module Name: src
Committed By: riastradh
Date: Sat Apr 9 12:06:48 UTC 2022
Modified Files:
src/common/lib/libc/arch/sparc64/atomic: membar_ops.S
Log Message:
sparc64: Fix membar_sync by issuing membar #StoreLoad.
In TSO this is the only memory barrier ever needed, and somehow we
got this wrong and instead issued an unnecessary membar #LoadLoad --
not needed even in PSO let alone in TSO.
XXX Apparently we may run userland programs with PSO or RMO, in which
case all of these membars need fixing:
PSO RMO
membar_consumer nop membar #LoadLoad
membar_producer membar #StoreStore membar #StoreStore
membar_enter nop membar #LoadLoad|LoadStore
membar_exit membar #StoreStore membar #LoadStore|StoreStore
membar_sync membar #StoreLoad|StoreStore
membar #...everything...
But at least this fixes the TSO case in which we run the kernel.
Also I'm not sure there's any non-TSO hardware out there in practice.
To generate a diff of this commit:
cvs rdiff -u -r1.6 -r1.7 src/common/lib/libc/arch/sparc64/atomic/membar_ops.S
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
