msm: kgsl: Make the "scratch" global buffer use a random GPU address
Select a random global GPU address for the "scratch" buffer that is used
by the ringbuffer for various tasks.
Change-Id: Ic0dedbaddda71dbf9cb2adab3c6c33a24d6a604c
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Harshitha Sai Neelati <hsaine@codeaurora.org>
diff --git a/drivers/gpu/msm/kgsl_iommu.c b/drivers/gpu/msm/kgsl_iommu.c
index 06f600d..d023170 100644
--- a/drivers/gpu/msm/kgsl_iommu.c
+++ b/drivers/gpu/msm/kgsl_iommu.c
@@ -20,6 +20,7 @@
#include <linux/msm_kgsl.h>
#include <linux/ratelimit.h>
#include <linux/of_platform.h>
+#include <linux/random.h>
#include <soc/qcom/scm.h>
#include <soc/qcom/secure_buffer.h>
#include <linux/compat.h>
@@ -224,7 +225,7 @@
static void kgsl_iommu_add_global(struct kgsl_mmu *mmu,
struct kgsl_memdesc *memdesc, const char *name)
{
- int bit;
+ u32 bit, start = 0;
u64 size = kgsl_memdesc_footprint(memdesc);
if (memdesc->gpuaddr != 0)
@@ -233,10 +234,26 @@
if (WARN_ON(global_pt_count >= GLOBAL_PT_ENTRIES))
return;
- bit = bitmap_find_next_zero_area(global_map, GLOBAL_MAP_PAGES,
- 0, size >> PAGE_SHIFT, 0);
+ if (WARN_ON(size > KGSL_IOMMU_GLOBAL_MEM_SIZE))
+ return;
- if (WARN_ON(bit >= GLOBAL_MAP_PAGES))
+ if (memdesc->priv & KGSL_MEMDESC_RANDOM) {
+ u32 range = GLOBAL_MAP_PAGES - (size >> PAGE_SHIFT);
+
+ start = get_random_int() % range;
+ }
+
+ while (start >= 0) {
+ bit = bitmap_find_next_zero_area(global_map, GLOBAL_MAP_PAGES,
+ start, size >> PAGE_SHIFT, 0);
+
+ if (bit < GLOBAL_MAP_PAGES)
+ break;
+
+ start--;
+ }
+
+ if (WARN_ON(start < 0))
return;
memdesc->gpuaddr =