ion: Handle the memory mapping correctly on x86
This patch modifies the ion page pool code to address
limitation in x86 PAT. When one physical page is mapped
to multiple virtual pages, the same cache policy
should be used. Add set_memory_wc/uc call to avoid aliases.
If not, all mappings will be cached(write back).
Change-Id: I98ee8902df0c80135dddfa998c4ca4c2bb44e40e
Signed-off-by: Zhebin Jin <zhebin.jin@intel.com>
Signed-off-by: Vinil Cheeramvelil <vinil.cheeramvelil@intel.com>
diff --git a/drivers/staging/android/ion/Kconfig b/drivers/staging/android/ion/Kconfig
index 3452346..301948c 100644
--- a/drivers/staging/android/ion/Kconfig
+++ b/drivers/staging/android/ion/Kconfig
@@ -33,3 +33,10 @@
help
Choose this option if you wish to use ion on an nVidia Tegra.
+config ION_POOL_CACHE_POLICY
+ bool "Ion set page pool cache policy"
+ depends on ION
+ default y if X86
+ help
+ Choose this option if need to explicity set cache policy of the
+ pages in the page pool.
diff --git a/drivers/staging/android/ion/ion_page_pool.c b/drivers/staging/android/ion/ion_page_pool.c
index 4b88f11..b021748 100644
--- a/drivers/staging/android/ion/ion_page_pool.c
+++ b/drivers/staging/android/ion/ion_page_pool.c
@@ -30,6 +30,8 @@
if (!page)
return NULL;
+ ion_page_pool_alloc_set_cache_policy(pool, page);
+
ion_pages_sync_for_device(NULL, page, PAGE_SIZE << pool->order,
DMA_BIDIRECTIONAL);
return page;
@@ -38,6 +40,7 @@
static void ion_page_pool_free_pages(struct ion_page_pool *pool,
struct page *page)
{
+ ion_page_pool_free_set_cache_policy(pool, page);
__free_pages(page, pool->order);
}
@@ -103,6 +106,11 @@
ion_page_pool_free_pages(pool, page);
}
+void ion_page_pool_free_immediate(struct ion_page_pool *pool, struct page *page)
+{
+ ion_page_pool_free_pages(pool, page);
+}
+
static int ion_page_pool_total(struct ion_page_pool *pool, bool high)
{
int count = pool->low_count;
diff --git a/drivers/staging/android/ion/ion_priv.h b/drivers/staging/android/ion/ion_priv.h
index 18a5f93..0e3b8a6 100644
--- a/drivers/staging/android/ion/ion_priv.h
+++ b/drivers/staging/android/ion/ion_priv.h
@@ -26,6 +26,9 @@
#include <linux/sched.h>
#include <linux/shrinker.h>
#include <linux/types.h>
+#ifdef CONFIG_ION_POOL_CACHE_POLICY
+#include <asm/cacheflush.h>
+#endif
#include "ion.h"
@@ -380,6 +383,37 @@
void ion_page_pool_destroy(struct ion_page_pool *);
struct page *ion_page_pool_alloc(struct ion_page_pool *);
void ion_page_pool_free(struct ion_page_pool *, struct page *);
+void ion_page_pool_free_immediate(struct ion_page_pool *, struct page *);
+
+#ifdef CONFIG_ION_POOL_CACHE_POLICY
+static inline void ion_page_pool_alloc_set_cache_policy
+ (struct ion_page_pool *pool,
+ struct page *page){
+ void *va = page_address(page);
+
+ if (va)
+ set_memory_wc((unsigned long)va, 1 << pool->order);
+}
+
+static inline void ion_page_pool_free_set_cache_policy
+ (struct ion_page_pool *pool,
+ struct page *page){
+ void *va = page_address(page);
+
+ if (va)
+ set_memory_wb((unsigned long)va, 1 << pool->order);
+
+}
+#else
+static inline void ion_page_pool_alloc_set_cache_policy
+ (struct ion_page_pool *pool,
+ struct page *page){ }
+
+static inline void ion_page_pool_free_set_cache_policy
+ (struct ion_page_pool *pool,
+ struct page *page){ }
+#endif
+
/** ion_page_pool_shrink - shrinks the size of the memory cached in the pool
* @pool: the pool
diff --git a/drivers/staging/android/ion/ion_system_heap.c b/drivers/staging/android/ion/ion_system_heap.c
index da2a63c..1f9feb7 100644
--- a/drivers/staging/android/ion/ion_system_heap.c
+++ b/drivers/staging/android/ion/ion_system_heap.c
@@ -85,8 +85,10 @@
if (!cached && !(buffer->private_flags & ION_PRIV_FLAG_SHRINKER_FREE)) {
struct ion_page_pool *pool = heap->pools[order_to_index(order)];
-
- ion_page_pool_free(pool, page);
+ if (buffer->private_flags & ION_PRIV_FLAG_SHRINKER_FREE)
+ ion_page_pool_free_immediate(pool, page);
+ else
+ ion_page_pool_free(pool, page);
} else {
__free_pages(page, order);
}
