On Thu, Sep 07, 2017 at 11:36:05AM -0600, Tycho Andersen wrote: > From: Juerg Haefliger <juerg.haefli...@canonical.com> > > If the page is unmapped by XPFO, a data cache flush results in a fatal > page fault, so let's temporarily map the region, flush the cache, and then > unmap it. > > v6: actually flush in the face of xpfo, and temporarily map the underlying > memory so it can be flushed correctly > > CC: linux-arm-ker...@lists.infradead.org > Signed-off-by: Juerg Haefliger <juerg.haefli...@canonical.com> > Signed-off-by: Tycho Andersen <ty...@docker.com> > --- > arch/arm64/mm/flush.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c > index 21a8d828cbf4..e335e3fd4fca 100644 > --- a/arch/arm64/mm/flush.c > +++ b/arch/arm64/mm/flush.c > @@ -20,6 +20,7 @@ > #include <linux/export.h> > #include <linux/mm.h> > #include <linux/pagemap.h> > +#include <linux/xpfo.h> > > #include <asm/cacheflush.h> > #include <asm/cache.h> > @@ -28,9 +29,15 @@ > void sync_icache_aliases(void *kaddr, unsigned long len) > { > unsigned long addr = (unsigned long)kaddr; > + unsigned long num_pages = XPFO_NUM_PAGES(addr, len); > + void *mapping[num_pages]; > > if (icache_is_aliasing()) { > + xpfo_temp_map(kaddr, len, mapping, > + sizeof(mapping[0]) * num_pages); > __clean_dcache_area_pou(kaddr, len); > + xpfo_temp_unmap(kaddr, len, mapping, > + sizeof(mapping[0]) * num_pages);
Does this create the mapping in-place? Can we not just kmap_atomic() an alias? Or is there a problem with that? Thanks, Mark.