1 files changed, 151 insertions, 0 deletions

diff --git a/arch/ia64/lib/csum_partial_copy.c b/arch/ia64/lib/csum_partial_copy.c
new file mode 100644
index 000000000000..36866e8a5d2b
--- /dev/null
+++ b/arch/ia64/lib/csum_partial_copy.c
@@ -0,0 +1,151 @@
+/*
+ * Network Checksum & Copy routine
+ *
+ * Copyright (C) 1999, 2003-2004 Hewlett-Packard Co
+ *      Stephane Eranian <eranian@hpl.hp.com>
+ *
+ * Most of the code has been imported from Linux/Alpha
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/string.h>
+
+#include <asm/uaccess.h>
+
+/*
+ * XXX Fixme: those 2 inlines are meant for debugging and will go away
+ */
+static inline unsigned
+short from64to16(unsigned long x)
+{
+        /* add up 32-bit words for 33 bits */
+        x = (x & 0xffffffff) + (x >> 32);
+        /* add up 16-bit and 17-bit words for 17+c bits */
+        x = (x & 0xffff) + (x >> 16);
+        /* add up 16-bit and 2-bit for 16+c bit */
+        x = (x & 0xffff) + (x >> 16);
+        /* add up carry.. */
+        x = (x & 0xffff) + (x >> 16);
+        return x;
+}
+
+static inline
+unsigned long do_csum_c(const unsigned char * buff, int len, unsigned int psum)
+{
+        int odd, count;
+        unsigned long result = (unsigned long)psum;
+
+        if (len <= 0)
+                goto out;
+        odd = 1 & (unsigned long) buff;
+        if (odd) {
+                result = *buff << 8;
+                len--;
+                buff++;
+        }
+        count = len >> 1;               /* nr of 16-bit words.. */
+        if (count) {
+                if (2 & (unsigned long) buff) {
+                        result += *(unsigned short *) buff;
+                        count--;
+                        len -= 2;
+                        buff += 2;
+                }
+                count >>= 1;            /* nr of 32-bit words.. */
+                if (count) {
+                        if (4 & (unsigned long) buff) {
+                                result += *(unsigned int *) buff;
+                                count--;
+                                len -= 4;
+                                buff += 4;
+                        }
+                        count >>= 1;    /* nr of 64-bit words.. */
+                        if (count) {
+                                unsigned long carry = 0;
+                                do {
+                                        unsigned long w = *(unsigned long *) buff;
+                                        count--;
+                                        buff += 8;
+                                        result += carry;
+                                        result += w;
+                                        carry = (w > result);
+                                } while (count);
+                                result += carry;
+                                result = (result & 0xffffffff) + (result >> 32);
+                        }
+                        if (len & 4) {
+                                result += *(unsigned int *) buff;
+                                buff += 4;
+                        }
+                }
+                if (len & 2) {
+                        result += *(unsigned short *) buff;
+                        buff += 2;
+                }
+        }
+        if (len & 1)
+                result += *buff;
+
+        result = from64to16(result);
+
+        if (odd)
+                result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
+
+out:
+        return result;
+}
+
+/*
+ * XXX Fixme
+ *
+ * This is very ugly but temporary. THIS NEEDS SERIOUS ENHANCEMENTS.
+ * But it's very tricky to get right even in C.
+ */
+extern unsigned long do_csum(const unsigned char *, long);
+
+static unsigned int
+do_csum_partial_copy_from_user (const unsigned char __user *src, unsigned char *dst,
+                                int len, unsigned int psum, int *errp)
+{
+        unsigned long result;
+
+        /* XXX Fixme
+         * for now we separate the copy from checksum for obvious
+         * alignment difficulties. Look at the Alpha code and you'll be
+         * scared.
+         */
+
+        if (__copy_from_user(dst, src, len) != 0 && errp)
+                *errp = -EFAULT;
+
+        result = do_csum(dst, len);
+
+        /* add in old sum, and carry.. */
+        result += psum;
+        /* 32+c bits -> 32 bits */
+        result = (result & 0xffffffff) + (result >> 32);
+        return result;
+}
+
+unsigned int
+csum_partial_copy_from_user (const unsigned char __user *src, unsigned char *dst,
+                             int len, unsigned int sum, int *errp)
+{
+        if (!access_ok(VERIFY_READ, src, len)) {
+                *errp = -EFAULT;
+                memset(dst, 0, len);
+                return sum;
+        }
+
+        return do_csum_partial_copy_from_user(src, dst, len, sum, errp);
+}
+
+unsigned int
+csum_partial_copy_nocheck(const unsigned char __user *src, unsigned char *dst,
+                          int len, unsigned int sum)
+{
+        return do_csum_partial_copy_from_user(src, dst, len, sum, NULL);
+}
+
+EXPORT_SYMBOL(csum_partial_copy_nocheck);