In csum_tcpudp_nofold, add 1 if the carry bit is set after adding the
destination IP address (32 bits) to the checksum (16 bits).
The lack of carry handling for this particular addition meant that a
destination address of *.*.255.255 (e.g. certain broadcasts) sometimes
resulted in an incorrect checksum. This bug has been present in the Meta
port since the code was written in the 2.4 days.
Reported-by: Marcin Nowakowski <marcin.nowakow...@pure.com>
Signed-off-by: James Hogan <james.ho...@imgtec.com>
---
I'll add this patch to my arch/metag fixes branch for v3.11.
arch/metag/include/asm/checksum.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/metag/include/asm/checksum.h
b/arch/metag/include/asm/checksum.h
index 999bf76..08dd1cc 100644
--- a/arch/metag/include/asm/checksum.h
+++ b/arch/metag/include/asm/checksum.h
@@ -64,7 +64,8 @@ static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32
daddr,
__wsum sum)
{
unsigned long len_proto = (proto + len) << 8;
- asm ("ADD %0, %0, %1\n"
+ asm ("ADDS %0, %0, %1\n"
+ "ADDCS %0, %0, #1\n"
"ADDS %0, %0, %2\n"
"ADDCS %0, %0, #1\n"
"ADDS %0, %0, %3\n"
--
1.8.1.2
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