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Message-Id: <20150203113927.8604D1A5F14@localhost.localdomain>
Date: Tue, 3 Feb 2015 12:39:27 +0100 (CET)
From: Christophe Leroy <christophe.leroy@....fr>
To: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>, scottwood@...escale.com
CC: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
Joakim Tjernlund <joakim.tjernlund@...nsmode.se>
Subject: [PATCH v2 2/2] powerpc32: add support for csum_add()
The C version of csum_add() as defined in include/net/checksum.h gives the
following assembly:
0: 7c 04 1a 14 add r0,r4,r3
4: 7c 64 00 10 subfc r3,r4,r0
8: 7c 63 19 10 subfe r3,r3,r3
c: 7c 63 00 50 subf r3,r3,r0
include/net/checksum.h also offers the possibility to define an arch specific
function.
This patch provides a ppc32 specific csum_add() inline function.
Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
v2: changed constraints on the __asm__
arch/powerpc/include/asm/checksum.h | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/arch/powerpc/include/asm/checksum.h b/arch/powerpc/include/asm/checksum.h
index cfe806a..1e48cc7 100644
--- a/arch/powerpc/include/asm/checksum.h
+++ b/arch/powerpc/include/asm/checksum.h
@@ -141,6 +141,18 @@ static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
{
return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
}
+
+#define HAVE_ARCH_CSUM_ADD
+static inline __wsum csum_add(__wsum csum, __wsum addend)
+{
+ __asm__("\n\
+ addc %0,%0,%1 \n\
+ addze %0,%0 \n\
+ "
+ : "+r" (csum) : "r" (addend));
+ return csum;
+}
+
#endif
#endif
#endif /* __KERNEL__ */
--
2.1.0
--
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