diff options
Diffstat (limited to 'arch/ia64/lib/csum_partial_copy.c')
-rw-r--r-- | arch/ia64/lib/csum_partial_copy.c | 151 |
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 0000000..36866e8 --- /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); |