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Diffstat (limited to 'arch/ia64/lib/csum_partial_copy.c')
-rw-r--r--arch/ia64/lib/csum_partial_copy.c151
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);