[PATCH] m68k IP checksum fix

M68k: revive csum_partial_copy_nocheck() after csum_partial_copy() was removed
in 2.5.44 (from Roman Zippel)

diff --git a/arch/m68k/lib/checksum.c b/arch/m68k/lib/checksum.c
index 3699c5a3e635dac82c5d358262940eaa049a6291..fb7ba6defbc49ff2443e344d15f76ae2a65d29aa 100644 (file)
--- a/arch/m68k/lib/checksum.c
+++ b/arch/m68k/lib/checksum.c
@@ -318,3 +318,103 @@ csum_partial_copy_from_user(const char *src, char *dst, int len,
 
        return(sum);
 }
+
+/*
+ * copy from kernel space while checksumming, otherwise like csum_partial
+ */
+
+unsigned int
+csum_partial_copy_nocheck(const char *src, char *dst, int len, int sum)
+{
+       unsigned long tmp1, tmp2;
+       __asm__("movel %2,%4\n\t"
+               "btst #1,%4\n\t"        /* Check alignment */
+               "jeq 2f\n\t"
+               "subql #2,%1\n\t"       /* buff%4==2: treat first word */
+               "jgt 1f\n\t"
+               "addql #2,%1\n\t"       /* len was == 2, treat only rest */
+               "jra 4f\n"
+            "1:\t"
+               "movew %2@+,%4\n\t"     /* add first word to sum */
+               "addw %4,%0\n\t"
+               "movew %4,%3@+\n\t"
+               "clrl %4\n\t"
+               "addxl %4,%0\n"         /* add X bit */
+            "2:\t"
+               /* unrolled loop for the main part: do 8 longs at once */
+               "movel %1,%4\n\t"       /* save len in tmp1 */
+               "lsrl #5,%1\n\t"        /* len/32 */
+               "jeq 2f\n\t"            /* not enough... */
+               "subql #1,%1\n"
+            "1:\t"
+               "movel %2@+,%5\n\t"
+               "addxl %5,%0\n\t"
+               "movel %5,%3@+\n\t"
+               "movel %2@+,%5\n\t"
+               "addxl %5,%0\n\t"
+               "movel %5,%3@+\n\t"
+               "movel %2@+,%5\n\t"
+               "addxl %5,%0\n\t"
+               "movel %5,%3@+\n\t"
+               "movel %2@+,%5\n\t"
+               "addxl %5,%0\n\t"
+               "movel %5,%3@+\n\t"
+               "movel %2@+,%5\n\t"
+               "addxl %5,%0\n\t"
+               "movel %5,%3@+\n\t"
+               "movel %2@+,%5\n\t"
+               "addxl %5,%0\n\t"
+               "movel %5,%3@+\n\t"
+               "movel %2@+,%5\n\t"
+               "addxl %5,%0\n\t"
+               "movel %5,%3@+\n\t"
+               "movel %2@+,%5\n\t"
+               "addxl %5,%0\n\t"
+               "movel %5,%3@+\n\t"
+               "dbra %1,1b\n\t"
+               "clrl %5\n\t"
+               "addxl %5,%0\n\t"       /* add X bit */
+               "clrw %1\n\t"
+               "subql #1,%1\n\t"
+               "jcc 1b\n"
+            "2:\t"
+               "movel %4,%1\n\t"       /* restore len from tmp1 */
+               "andw #0x1c,%4\n\t"     /* number of rest longs */
+               "jeq 4f\n\t"
+               "lsrw #2,%4\n\t"
+               "subqw #1,%4\n"
+            "3:\t"
+               /* loop for rest longs */
+               "movel %2@+,%5\n\t"
+               "addxl %5,%0\n\t"
+               "movel %5,%3@+\n\t"
+               "dbra %4,3b\n\t"
+               "clrl %5\n\t"
+               "addxl %5,%0\n"         /* add X bit */
+            "4:\t"
+               /* now check for rest bytes that do not fit into longs */
+               "andw #3,%1\n\t"
+               "jeq 7f\n\t"
+               "clrl %5\n\t"           /* clear tmp2 for rest bytes */
+               "subqw #2,%1\n\t"
+               "jlt 5f\n\t"
+               "movew %2@+,%5\n\t"     /* have rest >= 2: get word */
+               "movew %5,%3@+\n\t"
+               "swap %5\n\t"           /* into bits 16..31 */
+               "tstw %1\n\t"           /* another byte? */
+               "jeq 6f\n"
+            "5:\t"
+               "moveb %2@,%5\n\t"      /* have odd rest: get byte */
+               "moveb %5,%3@+\n\t"
+               "lslw #8,%5\n"          /* into bits 8..15; 16..31 untouched */
+            "6:\t"
+               "addl %5,%0\n\t"        /* now add rest long to sum */
+               "clrl %5\n\t"
+               "addxl %5,%0\n"         /* add X bit */
+            "7:\t"
+               : "=d" (sum), "=d" (len), "=a" (src), "=a" (dst),
+                 "=&d" (tmp1), "=&d" (tmp2)
+               : "0" (sum), "1" (len), "2" (src), "3" (dst)
+           );
+    return(sum);
+}

diff --git a/include/asm-m68k/checksum.h b/include/asm-m68k/checksum.h
index f3fa10674a9e595f83dc082969287d0317426b77..25ef68a2109fe219e61fbf0adf31e930420e1c43 100644 (file)
--- a/include/asm-m68k/checksum.h
+++ b/include/asm-m68k/checksum.h
@@ -26,8 +26,8 @@ unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum)
 extern unsigned int csum_partial_copy_from_user(const char *src, char *dst,
                                                int len, int sum, int *csum_err);
 
-#define csum_partial_copy_nocheck(src, dst, len, sum)  \
-       csum_partial_copy((src), (dst), (len), (sum))
+extern unsigned int csum_partial_copy_nocheck(const char *src, char *dst,
+                                             int len, int sum);
 
 /*
  *     This is a version of ip_compute_csum() optimized for IP headers,