[PATCH v6 09/11] arm64/mm: disable section/contiguous mappings if XPFO is enabled

Tycho Andersen
2017-09-07T17:37:58Z

XPFO doesn't support section/contiguous mappings yet, so let's disable it
if XPFO is turned on.

Thanks to Laura Abbot for the simplification from v5, and Mark Rutland for
pointing out we need NO_CONT_MAPPINGS too.

CC: linux-arm-kernel@lists.infradead.org
Signed-off-by: Tycho Andersen <tycho@docker.com>
---
arch/arm64/mm/mmu.c | 2 +-
include/linux/xpfo.h | 4 ++++
mm/xpfo.c | 6 ++++++
3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index f1eb15e0e864..34bb95303cce 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -420,7 +420,7 @@ static void __init map_mem(pgd_t *pgd)
struct memblock_region *reg;
int flags = 0;

- if (debug_pagealloc_enabled())
+ if (debug_pagealloc_enabled() || xpfo_enabled())
flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;

/*
diff --git a/include/linux/xpfo.h b/include/linux/xpfo.h
index d37a06c9d62c..1693af1a0293 100644
--- a/include/linux/xpfo.h
+++ b/include/linux/xpfo.h
@@ -43,6 +43,8 @@ void xpfo_temp_map(const void *addr, size_t size, void **mapping,
void xpfo_temp_unmap(const void *addr, size_t size, void **mapping,
size_t mapping_len);

+bool xpfo_enabled(void);
+
#else /* !CONFIG_XPFO */

static inline void xpfo_kmap(void *kaddr, struct page *page) { }
@@ -65,6 +67,8 @@ static inline void xpfo_temp_unmap(const void *addr, size_t size,
}

+static inline bool xpfo_enabled(void) { return false; }
+
#endif /* CONFIG_XPFO */

#endif /* _LINUX_XPFO_H */
diff --git a/mm/xpfo.c b/mm/xpfo.c
index f79075bf7d65..25fba05d01bd 100644
--- a/mm/xpfo.c
+++ b/mm/xpfo.c
@@ -70,6 +70,12 @@ struct page_ext_operations page_xpfo_ops = {
.init = init_xpfo,
};

+bool __init xpfo_enabled(void)
+{
+ return !xpfo_disabled;
+}
+EXPORT_SYMBOL(xpfo_enabled);
+
static inline struct xpfo *lookup_xpfo(struct page *page)
{
struct page_ext *page_ext = lookup_page_ext(page);
--
2.11.0