Re: linux-next: manual merge of the mips tree with the mips-fixes tree

From: Paul Burton
Date: Tue Feb 05 2019 - 18:35:39 EST

Hi Stephen,

On Wed, Feb 06, 2019 at 09:17:36AM +1100, Stephen Rothwell wrote:
> Hi all,
> Today's linux-next merge of the mips tree got conflicts in:
> arch/mips/include/asm/barrier.h
> arch/mips/include/asm/pgtable.h
> between commit:
> e02e07e3127d ("MIPS: Loongson: Introduce and use loongson_llsc_mb()")
> from the mips-fixes tree and commits:
> 535113896e80 ("MIPS: Add GINVT instruction helpers")
> 82f4f66ddf11 ("MIPS: Remove open-coded cmpxchg() in set_pte()")
> from the mips tree.
> I fixed it up (see below and for the latter file, I used the mips tree
> version but wondered if cmpxchg() needs the fixups from the mips-fixes
> tree commit)

Thanks - that looks good.

cmpxchg() doesn't need the added loongson_llsc_mb() barrier that
set_pte() has in mips-fixes because for the affected Loongson 3
configurations the smp_mb__before_llsc() that cmpxchg() already contains
is equivalent (both will emit a "sync 0" instruction).