From: Haavard Skinnemoen The existing implementation of ioremap_page_range(), which was taken from i386, does this: flush_cache_all(); /* modify page tables */ flush_tlb_all(); I think this is a bit defensive, so this patch changes the generic implementation to do: /* modify page tables */ flush_cache_vmap(start, end); instead, which is similar to what vmalloc() does. This should still be correct because we never modify existing PTEs. According to James Bottomley: The problem the flush_tlb_all() is trying to solve is to avoid stale tlb entries in the ioremap area. We're just being conservative by flushing on both map and unmap. Technically what vmalloc/vfree does (only flush the tlb on unmap) is just fine because it means that the only tlb entries in the remap area must belong to in-use mappings. Signed-off-by: Haavard Skinnemoen Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Russell King Cc: Mikael Starvik Cc: Andi Kleen Cc: Cc: Ralf Baechle Cc: Kyle McMartin Cc: Martin Schwidefsky Cc: Paul Mundt Signed-off-by: Andrew Morton --- lib/ioremap.c | 4 +--- 1 files changed, 1 insertion(+), 3 deletions(-) diff -puN lib/ioremap.c~generic-ioremap_page_range-flush_cache_vmap lib/ioremap.c --- a/lib/ioremap.c~generic-ioremap_page_range-flush_cache_vmap +++ a/lib/ioremap.c @@ -75,8 +75,6 @@ int ioremap_page_range(unsigned long add BUG_ON(addr >= end); - flush_cache_all(); - start = addr; phys_addr -= addr; pgd = pgd_offset_k(addr); @@ -87,7 +85,7 @@ int ioremap_page_range(unsigned long add break; } while (pgd++, addr = next, addr != end); - flush_tlb_all(); + flush_cache_vmap(start, end); return err; } _