Merge tag 'v3.10.68' into update

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / arm / mm / dma-mapping.c

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 4df2b7834ec8b1c1656af182210329eaa8f1e17c..9c5c1d2dced5c556a655b0316bffe41eda9edde4 100644 (file)
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -429,12 +429,21 @@ void __init dma_contiguous_remap(void)
                map.type = MT_MEMORY_DMA_READY;
 
                /*
-                * Clear previous low-memory mapping
+                * Clear previous low-memory mapping to ensure that the
+                * TLB does not see any conflicting entries, then flush
+                * the TLB of the old entries before creating new mappings.
+                *
+                * This ensures that any speculatively loaded TLB entries
+                * (even though they may be rare) can not cause any problems,
+                * and ensures that this code is architecturally compliant.
                 */
                for (addr = __phys_to_virt(start); addr < __phys_to_virt(end);
                     addr += PMD_SIZE)
                        pmd_clear(pmd_off_k(addr));
 
+               flush_tlb_kernel_range(__phys_to_virt(start),
+                                      __phys_to_virt(end));
+
                iotable_init(&map, 1);
        }
 }