video: tegra: nvmap: clean cache during page allocations into page pool

Clean cache during page allocations into page pool to
avoid cache clean overhead at the time of allocation.
Increase page pool refill size to 1MB from 512KB.

Bug 1539190

Change-Id: I6c45782e54879541f7b518bbbb016383b24e376b
Signed-off-by: Krishna Reddy <vdumpa@nvidia.com>
Reviewed-on: http://git-master/r/453197
Reviewed-by: Sri Krishna Chowdary <schowdary@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Alex Waterman <alexw@nvidia.com>
Reviewed-by: Michael I Gold <gold@nvidia.com>
[ccross: moved on top of background zeroing patches, replaced
 atomic with bool since it has to be protected by a lock anyways]
Signed-off-by: Colin Cross <ccross@android.com>
Reviewed-on: http://git-master/r/664676
Reviewed-on: http://git-master/r/736430
Tested-by: Alex Waterman <alexw@nvidia.com>

3 files changed, 33 insertions, 3 deletions

diff --git a/drivers/video/tegra/nvmap/nvmap_handle.c b/drivers/video/tegra/nvmap/nvmap_handle.c
index 813496596a14..b14035b2ac12 100644
--- a/drivers/video/tegra/nvmap/nvmap_handle.c
+++ b/drivers/video/tegra/nvmap/nvmap_handle.c
@@ -206,10 +206,11 @@ static int handle_page_alloc(struct nvmap_client *client,
 	 * FIXME: For ARMv7 we don't have __clean_dcache_page() so we continue
 	 * to use the flush cache version.
 	 */
+	if (page_index < nr_page)
 #ifdef ARM64
-	nvmap_clean_cache(pages, nr_page);
+		nvmap_clean_cache(&pages[page_index], nr_page - page_index);
 #else
-	nvmap_flush_cache(pages, nr_page);
+		nvmap_flush_cache(&pages[page_index], nr_page - page_index);
 #endif
 
 	h->size = size;
diff --git a/drivers/video/tegra/nvmap/nvmap_pp.c b/drivers/video/tegra/nvmap/nvmap_pp.c
index af34da678261..a9f5c3eb4cfd 100644
--- a/drivers/video/tegra/nvmap/nvmap_pp.c
+++ b/drivers/video/tegra/nvmap/nvmap_pp.c
@@ -34,7 +34,7 @@
 #include "nvmap_priv.h"
 
 #define NVMAP_TEST_PAGE_POOL_SHRINKER     1
-#define PENDING_PAGES_SIZE                32
+#define PENDING_PAGES_SIZE                (SZ_1M / PAGE_SIZE)
 
 static bool enable_pp = 1;
 static int pool_size;
@@ -59,6 +59,23 @@ static inline void __pp_dbg_var_add(u64 *dbg_var, u32 nr)
 static int __nvmap_page_pool_fill_lots_locked(struct nvmap_page_pool *pool,
 				       struct page **pages, u32 nr);
 
+/*
+ * Make sure any data in the caches is cleaned out before
+ * passing these pages to userspace. otherwise, It can lead to
+ * corruption in pages that get mapped as something
+ * other than WB in userspace and leaked kernel data.
+ *
+ * Must be called with pool->lock held.
+ */
+static void pp_clean_cache(struct nvmap_page_pool *pool)
+{
+	if (pool->contains_dirty_pages) {
+		inner_clean_cache_all();
+		outer_clean_all();
+		pool->contains_dirty_pages = false;
+	}
+}
+
 static inline struct page *get_zero_list_page(struct nvmap_page_pool *pool)
 {
 	struct page *page;
@@ -144,6 +161,13 @@ static void nvmap_pp_do_background_zero_pages(struct nvmap_page_pool *pool)
 out:
 	for (; ret < i; ret++)
 		__free_page(pending_zero_pages[ret]);
+
+	/* clean cache in the background so that allocations immediately
+	 * after fill don't suffer the cache clean overhead.
+	 */
+	mutex_lock(&pool->lock);
+	pp_clean_cache(pool);
+	mutex_unlock(&pool->lock);
 }
 
 /*
@@ -197,6 +221,7 @@ static struct page *nvmap_page_pool_alloc_locked(struct nvmap_page_pool *pool,
 	if (IS_ENABLED(CONFIG_NVMAP_PAGE_POOL_DEBUG))
 		BUG_ON(pool->count == 0);
 
+	pp_clean_cache(pool);
 	page = get_page_list_page(pool);
 	if (!page)
 		return NULL;
@@ -228,6 +253,7 @@ int nvmap_page_pool_alloc_lots(struct nvmap_page_pool *pool,
 		return 0;
 
 	mutex_lock(&pool->lock);
+	pp_clean_cache(pool);
 
 	real_nr = min_t(u32, nr, pool->count);
 
@@ -267,6 +293,8 @@ static int __nvmap_page_pool_fill_lots_locked(struct nvmap_page_pool *pool,
 	if (!enable_pp)
 		return 0;
 
+	pool->contains_dirty_pages = true;
+
 	real_nr = min_t(u32, pool->max - pool->count, nr);
 	if (real_nr == 0)
 		return 0;
diff --git a/drivers/video/tegra/nvmap/nvmap_priv.h b/drivers/video/tegra/nvmap/nvmap_priv.h
index 0eeaee4d7e69..977897a61aa2 100644
--- a/drivers/video/tegra/nvmap/nvmap_priv.h
+++ b/drivers/video/tegra/nvmap/nvmap_priv.h
@@ -176,6 +176,7 @@ struct nvmap_page_pool {
 	int to_zero; /* Number of pages on the zero list */
 	struct list_head page_list;
 	struct list_head zero_list;
+	bool contains_dirty_pages;
 
 #ifdef CONFIG_NVMAP_PAGE_POOL_DEBUG
 	u64 allocs;