ARM: Fix ioremap_cached()/ioremap_wc() for SMP platforms

Write combining/cached device mappings are not setting the shared bit,
which could potentially cause problems on SMP systems since the cache
lines won't participate in the cache coherency protocol.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 9d4da6ac28eb..4223d086aa17 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -420,6 +420,10 @@ static void __init build_mem_type_table(void)
                 user_pgprot |= L_PTE_SHARED;
                 kern_pgprot |= L_PTE_SHARED;
                 vecs_pgprot |= L_PTE_SHARED;
+                mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_S;
+                mem_types[MT_DEVICE_WC].prot_pte |= L_PTE_SHARED;
+                mem_types[MT_DEVICE_CACHED].prot_sect |= PMD_SECT_S;
+                mem_types[MT_DEVICE_CACHED].prot_pte |= L_PTE_SHARED;
                 mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S;
                 mem_types[MT_MEMORY_NONCACHED].prot_sect |= PMD_SECT_S;
 #endif