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]>
---
lib/ioremap.c | 4 +---
1 files changed, 1 insertions(+), 3 deletions(-)
diff --git a/lib/ioremap.c b/lib/ioremap.c
index 6419101..d2cb1eb 100644
--- a/lib/ioremap.c
+++ b/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;
}
--
1.4.0
-
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