Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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Merge tag 'powerpc-4.18-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
"One fix for a regression in a recent TLB flush optimisation, which
caused us to incorrectly not send TLB invalidations to coprocessors.
Thanks to Frederic Barrat, Nicholas Piggin, Vaibhav Jain"
* tag 'powerpc-4.18-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/64s/radix: Fix missing global invalidations when removing copro
+21
-12
+21
-12
arch/powerpc/include/asm/mmu_context.h
+21
-12
arch/powerpc/include/asm/mmu_context.h
···
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{
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int c;
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-
c = atomic_dec_if_positive(&mm->context.copros);
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-
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/* Detect imbalance between add and remove */
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WARN_ON(c < 0);
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-
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/*
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* Need to broadcast a global flush of the full mm before
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* decrementing active_cpus count, as the next TLBI may be
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* local and the nMMU and/or PSL need to be cleaned up.
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* Should be rare enough so that it's acceptable.
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+
* When removing the last copro, we need to broadcast a global
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+
* flush of the full mm, as the next TLBI may be local and the
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+
* nMMU and/or PSL need to be cleaned up.
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+
*
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* Both the 'copros' and 'active_cpus' counts are looked at in
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* flush_all_mm() to determine the scope (local/global) of the
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* TLBIs, so we need to flush first before decrementing
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* 'copros'. If this API is used by several callers for the
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+
* same context, it can lead to over-flushing. It's hopefully
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* not common enough to be a problem.
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*
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* Skip on hash, as we don't know how to do the proper flush
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* for the time being. Invalidations will remain global if
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* used on hash.
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* used on hash. Note that we can't drop 'copros' either, as
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* it could make some invalidations local with no flush
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* in-between.
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*/
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if (c == 0 && radix_enabled()) {
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+
if (radix_enabled()) {
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flush_all_mm(mm);
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-
dec_mm_active_cpus(mm);
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+
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+
c = atomic_dec_if_positive(&mm->context.copros);
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+
/* Detect imbalance between add and remove */
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+
WARN_ON(c < 0);
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+
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+
if (c == 0)
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dec_mm_active_cpus(mm);
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}
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}
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#else