[PATCH] Generic ioremap_page_range: flush_cache_vmap
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 <[email protected]>
Cc: Richard Henderson <[email protected]>
Cc: Ivan Kokshaysky <[email protected]>
Cc: Russell King <[email protected]>
Cc: Mikael Starvik <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: <[email protected]>
Cc: Ralf Baechle <[email protected]>
Cc: Kyle McMartin <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Paul Mundt <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/lib/ioremap.c b/lib/ioremap.c
index 29c810e..99fa277 100644
--- a/lib/ioremap.c
+++ b/lib/ioremap.c
@@ -76,8 +76,6 @@
BUG_ON(addr >= end);
- flush_cache_all();
-
start = addr;
phys_addr -= addr;
pgd = pgd_offset_k(addr);
@@ -88,7 +86,7 @@
break;
} while (pgd++, addr = next, addr != end);
- flush_tlb_all();
+ flush_cache_vmap(start, end);
return err;
}
