| Message ID | 20170907173609.22696-8-tycho@docker.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Sep 07, 2017 at 11:36:05AM -0600, Tycho Andersen wrote: > From: Juerg Haefliger <juerg.haefliger@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-kernel@lists.infradead.org > Signed-off-by: Juerg Haefliger <juerg.haefliger@canonical.com> > Signed-off-by: Tycho Andersen <tycho@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.
On Thu, Sep 14, 2017 at 07:25:56PM +0100, Mark Rutland wrote: > On Thu, Sep 07, 2017 at 11:36:05AM -0600, Tycho Andersen wrote: > > From: Juerg Haefliger <juerg.haefliger@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-kernel@lists.infradead.org > > Signed-off-by: Juerg Haefliger <juerg.haefliger@canonical.com> > > Signed-off-by: Tycho Andersen <tycho@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? I think what we really want is something like vmap(), looking at xpfo_temp_map() it seems like the implementation is completely wrong. I wonder if what you mentioned at LSS is possible though: doing cache management with userspace primitives instead of mapping the region just to flush it. Cheers, Tycho
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); __flush_icache_all(); } else { flush_icache_range(addr, addr + len);