[PATCH] Fix ioremap_cached()/ioremap_wc() for SMP platforms

[Russell King - ARM Linux]

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 at arm.linux.org.uk>
--
This doesn't make it any more legal to use ioremap*() on main system
RAM than it was before this change; it does mean that ioremap_wc()
regions are correctly marked as shared which happens to agree with
the main system RAM mappings.  Strictly to the arch. spec. for ARMv6+,
it remains "unpredictable" to use ioremap*() on main system RAM.

 arch/arm/mm/mmu.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 9d4da6a..4223d08 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