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Message-Id: <807dbc9449077e36752c649c09ae1c0d70e45254.1442876807.git.christophe.leroy@c-s.fr>
Date: Tue, 22 Sep 2015 16:34:25 +0200 (CEST)
From: Christophe Leroy <christophe.leroy@....fr>
To: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>, scottwood@...escale.com
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
netdev@...r.kernel.org
Subject: [PATCH 4/9] powerpc: inline ip_fast_csum()
In several architectures, ip_fast_csum() is inlined
There are functions like ip_send_check() which do nothing
much more than calling ip_fast_csum().
Inlining ip_fast_csum() allows the compiler to optimise better
Suggested-by: Eric Dumazet <eric.dumazet@...il.com>
Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
arch/powerpc/include/asm/checksum.h | 46 +++++++++++++++++++++++++++++++------
arch/powerpc/lib/checksum_32.S | 21 -----------------
arch/powerpc/lib/checksum_64.S | 27 ----------------------
arch/powerpc/lib/ppc_ksyms.c | 1 -
4 files changed, 39 insertions(+), 56 deletions(-)
diff --git a/arch/powerpc/include/asm/checksum.h b/arch/powerpc/include/asm/checksum.h
index afa6722..56deea8 100644
--- a/arch/powerpc/include/asm/checksum.h
+++ b/arch/powerpc/include/asm/checksum.h
@@ -9,16 +9,9 @@
* 2 of the License, or (at your option) any later version.
*/
-/*
- * This is a version of ip_compute_csum() optimized for IP headers,
- * which always checksum on 4 octet boundaries. ihl is the number
- * of 32-bit words and is always >= 5.
- */
#ifdef CONFIG_GENERIC_CSUM
#include <asm-generic/checksum.h>
#else
-extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
-
/*
* computes the checksum of a memory block at buff, length len,
* and adds in "sum" (32-bit)
@@ -137,6 +130,45 @@ static inline __wsum csum_add(__wsum csum, __wsum addend)
#endif
}
+/*
+ * This is a version of ip_compute_csum() optimized for IP headers,
+ * which always checksum on 4 octet boundaries. ihl is the number
+ * of 32-bit words and is always >= 5.
+ */
+static inline __wsum ip_fast_csum_nofold(const void *iph, unsigned int ihl)
+{
+ u32 *ptr = (u32 *)iph + 1;
+#ifdef __powerpc64__
+ unsigned int i;
+ u64 s = *(__force u32 *)iph;
+
+ for (i = 0; i < ihl - 1; i++, ptr++)
+ s += *ptr;
+ s += (s >> 32);
+ return (__force __wsum)s;
+
+#else
+ __wsum sum, tmp;
+
+ asm("mtctr %3;"
+ "addc %0,%4,%5;"
+ "1:lwzu %1, 4(%2);"
+ "adde %0,%0,%1;"
+ "bdnz 1b;"
+ "addze %0,%0;"
+ : "=r"(sum), "=r"(tmp), "+b"(ptr)
+ : "r"(ihl - 2), "r"(*(u32 *)iph), "r"(*ptr)
+ : "ctr", "xer", "memory");
+
+ return sum;
+#endif
+}
+
+static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
+{
+ return csum_fold(ip_fast_csum_nofold(iph, ihl));
+}
+
#endif
#endif /* __KERNEL__ */
#endif
diff --git a/arch/powerpc/lib/checksum_32.S b/arch/powerpc/lib/checksum_32.S
index 6d67e05..0d7eba3 100644
--- a/arch/powerpc/lib/checksum_32.S
+++ b/arch/powerpc/lib/checksum_32.S
@@ -20,27 +20,6 @@
.text
/*
- * ip_fast_csum(buf, len) -- Optimized for IP header
- * len is in words and is always >= 5.
- */
-_GLOBAL(ip_fast_csum)
- lwz r0,0(r3)
- lwzu r5,4(r3)
- addic. r4,r4,-2
- addc r0,r0,r5
- mtctr r4
- blelr-
-1: lwzu r4,4(r3)
- adde r0,r0,r4
- bdnz 1b
- addze r0,r0 /* add in final carry */
- rlwinm r3,r0,16,0,31 /* fold two halves together */
- add r3,r0,r3
- not r3,r3
- srwi r3,r3,16
- blr
-
-/*
* computes the checksum of a memory block at buff, length len,
* and adds in "sum" (32-bit)
*
diff --git a/arch/powerpc/lib/checksum_64.S b/arch/powerpc/lib/checksum_64.S
index f3ef354..f53f4ab 100644
--- a/arch/powerpc/lib/checksum_64.S
+++ b/arch/powerpc/lib/checksum_64.S
@@ -18,33 +18,6 @@
#include <asm/ppc_asm.h>
/*
- * ip_fast_csum(r3=buf, r4=len) -- Optimized for IP header
- * len is in words and is always >= 5.
- *
- * In practice len == 5, but this is not guaranteed. So this code does not
- * attempt to use doubleword instructions.
- */
-_GLOBAL(ip_fast_csum)
- lwz r0,0(r3)
- lwzu r5,4(r3)
- addic. r4,r4,-2
- addc r0,r0,r5
- mtctr r4
- blelr-
-1: lwzu r4,4(r3)
- adde r0,r0,r4
- bdnz 1b
- addze r0,r0 /* add in final carry */
- rldicl r4,r0,32,0 /* fold two 32-bit halves together */
- add r0,r0,r4
- srdi r0,r0,32
- rlwinm r3,r0,16,0,31 /* fold two halves together */
- add r3,r0,r3
- not r3,r3
- srwi r3,r3,16
- blr
-
-/*
* Computes the checksum of a memory block at buff, length len,
* and adds in "sum" (32-bit).
*
diff --git a/arch/powerpc/lib/ppc_ksyms.c b/arch/powerpc/lib/ppc_ksyms.c
index f5e427e..8cd5c0b 100644
--- a/arch/powerpc/lib/ppc_ksyms.c
+++ b/arch/powerpc/lib/ppc_ksyms.c
@@ -19,7 +19,6 @@ EXPORT_SYMBOL(strncmp);
#ifndef CONFIG_GENERIC_CSUM
EXPORT_SYMBOL(csum_partial);
EXPORT_SYMBOL(csum_partial_copy_generic);
-EXPORT_SYMBOL(ip_fast_csum);
#endif
EXPORT_SYMBOL(__copy_tofrom_user);
--
2.1.0
--
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