Viewing file:  csum_partial_copy.c (9.16 KB) -rw-r--r--
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/*
* csum_partial_copy - do IP checksumming and copy
*
* (C) Copyright 1996 Linus Torvalds
* accellerated versions (and 21264 assembly versions ) contributed by
* Rick Gorton <rick.gorton@alpha-processor.com>
*
* Don't look at this too closely - you'll go mad. The things
* we do for performance..
*/
#include <linux/types.h>
#include <linux/string.h>
#include <asm/uaccess.h>
#define ldq_u(x,y) \
__asm__ __volatile__("ldq_u %0,%1":"=r" (x):"m" (*(const unsigned long *)(y)))
#define stq_u(x,y) \
__asm__ __volatile__("stq_u %1,%0":"=m" (*(unsigned long *)(y)):"r" (x))
#define extql(x,y,z) \
__asm__ __volatile__("extql %1,%2,%0":"=r" (z):"r" (x),"r" (y))
#define extqh(x,y,z) \
__asm__ __volatile__("extqh %1,%2,%0":"=r" (z):"r" (x),"r" (y))
#define mskql(x,y,z) \
__asm__ __volatile__("mskql %1,%2,%0":"=r" (z):"r" (x),"r" (y))
#define mskqh(x,y,z) \
__asm__ __volatile__("mskqh %1,%2,%0":"=r" (z):"r" (x),"r" (y))
#define insql(x,y,z) \
__asm__ __volatile__("insql %1,%2,%0":"=r" (z):"r" (x),"r" (y))
#define insqh(x,y,z) \
__asm__ __volatile__("insqh %1,%2,%0":"=r" (z):"r" (x),"r" (y))
#define __get_user_u(x,ptr) \
({ \
long __guu_err; \
__asm__ __volatile__( \
"1: ldq_u %0,%2\n" \
"2:\n" \
".section __ex_table,\"a\"\n" \
" .gprel32 1b\n" \
" lda %0,2b-1b(%1)\n" \
".previous" \
: "=r"(x), "=r"(__guu_err) \
: "m"(__m(ptr)), "1"(0)); \
__guu_err; \
})
#define __put_user_u(x,ptr) \
({ \
long __puu_err; \
__asm__ __volatile__( \
"1: stq_u %2,%1\n" \
"2:\n" \
".section __ex_table,\"a\"\n" \
" .gprel32 1b" \
" lda $31,2b-1b(%0)\n" \
".previous" \
: "=r"(__puu_err) \
: "m"(__m(addr)), "rJ"(x), "0"(0)); \
__puu_err; \
})
static inline unsigned short from64to16(unsigned long x)
{
/* Using extract instructions is a bit more efficient
than the original shift/bitmask version. */
union {
unsigned long ul;
unsigned int ui[2];
unsigned short us[4];
} in_v, tmp_v, out_v;
in_v.ul = x;
tmp_v.ul = (unsigned long) in_v.ui[0] + (unsigned long) in_v.ui[1];
/* Since the bits of tmp_v.sh[3] are going to always be zero,
we don't have to bother to add that in. */
out_v.ul = (unsigned long) tmp_v.us[0] + (unsigned long) tmp_v.us[1]
+ (unsigned long) tmp_v.us[2];
/* Similarly, out_v.us[2] is always zero for the final add. */
return out_v.us[0] + out_v.us[1];
}
/*
* Ok. This isn't fun, but this is the EASY case.
*/
static inline unsigned long
csum_partial_cfu_aligned(const unsigned long *src, unsigned long *dst,
long len, unsigned long checksum,
int *errp)
{
unsigned long carry = 0;
int err = 0;
while (len >= 0) {
unsigned long word;
err |= __get_user(word, src);
checksum += carry;
src++;
checksum += word;
len -= 8;
carry = checksum < word;
*dst = word;
dst++;
}
len += 8;
checksum += carry;
if (len) {
unsigned long word, tmp;
err |= __get_user(word, src);
tmp = *dst;
mskql(word, len, word);
checksum += word;
mskqh(tmp, len, tmp);
carry = checksum < word;
*dst = word | tmp;
checksum += carry;
}
if (err) *errp = err;
return checksum;
}
/*
* This is even less fun, but this is still reasonably
* easy.
*/
static inline unsigned long
csum_partial_cfu_dest_aligned(const unsigned long *src, unsigned long *dst,
unsigned long soff,
long len, unsigned long checksum,
int *errp)
{
unsigned long first;
unsigned long word, carry;
unsigned long lastsrc = 7+len+(unsigned long)src;
int err = 0;
err |= __get_user_u(first,src);
carry = 0;
while (len >= 0) {
unsigned long second;
err |= __get_user_u(second, src+1);
extql(first, soff, word);
len -= 8;
src++;
extqh(second, soff, first);
checksum += carry;
word |= first;
first = second;
checksum += word;
*dst = word;
dst++;
carry = checksum < word;
}
len += 8;
checksum += carry;
if (len) {
unsigned long tmp;
unsigned long second;
err |= __get_user_u(second, lastsrc);
tmp = *dst;
extql(first, soff, word);
extqh(second, soff, first);
word |= first;
mskql(word, len, word);
checksum += word;
mskqh(tmp, len, tmp);
carry = checksum < word;
*dst = word | tmp;
checksum += carry;
}
if (err) *errp = err;
return checksum;
}
/*
* This is slightly less fun than the above..
*/
static inline unsigned long
csum_partial_cfu_src_aligned(const unsigned long *src, unsigned long *dst,
unsigned long doff,
long len, unsigned long checksum,
unsigned long partial_dest,
int *errp)
{
unsigned long carry = 0;
unsigned long word;
unsigned long second_dest;
int err = 0;
mskql(partial_dest, doff, partial_dest);
while (len >= 0) {
err |= __get_user(word, src);
len -= 8;
insql(word, doff, second_dest);
checksum += carry;
stq_u(partial_dest | second_dest, dst);
src++;
checksum += word;
insqh(word, doff, partial_dest);
carry = checksum < word;
dst++;
}
len += 8;
if (len) {
checksum += carry;
err |= __get_user(word, src);
mskql(word, len, word);
len -= 8;
checksum += word;
insql(word, doff, second_dest);
len += doff;
carry = checksum < word;
partial_dest |= second_dest;
if (len >= 0) {
stq_u(partial_dest, dst);
if (!len) goto out;
dst++;
insqh(word, doff, partial_dest);
}
doff = len;
}
ldq_u(second_dest, dst);
mskqh(second_dest, doff, second_dest);
stq_u(partial_dest | second_dest, dst);
out:
checksum += carry;
if (err) *errp = err;
return checksum;
}
/*
* This is so totally un-fun that it's frightening. Don't
* look at this too closely, you'll go blind.
*/
static inline unsigned long
csum_partial_cfu_unaligned(const unsigned long * src, unsigned long * dst,
unsigned long soff, unsigned long doff,
long len, unsigned long checksum,
unsigned long partial_dest,
int *errp)
{
unsigned long carry = 0;
unsigned long first;
unsigned long lastsrc;
int err = 0;
err |= __get_user_u(first, src);
lastsrc = 7+len+(unsigned long)src;
mskql(partial_dest, doff, partial_dest);
while (len >= 0) {
unsigned long second, word;
unsigned long second_dest;
err |= __get_user_u(second, src+1);
extql(first, soff, word);
checksum += carry;
len -= 8;
extqh(second, soff, first);
src++;
word |= first;
first = second;
insql(word, doff, second_dest);
checksum += word;
stq_u(partial_dest | second_dest, dst);
carry = checksum < word;
insqh(word, doff, partial_dest);
dst++;
}
len += doff;
checksum += carry;
if (len >= 0) {
unsigned long second, word;
unsigned long second_dest;
err |= __get_user_u(second, lastsrc);
extql(first, soff, word);
extqh(second, soff, first);
word |= first;
first = second;
mskql(word, len-doff, word);
checksum += word;
insql(word, doff, second_dest);
carry = checksum < word;
stq_u(partial_dest | second_dest, dst);
if (len) {
ldq_u(second_dest, dst+1);
insqh(word, doff, partial_dest);
mskqh(second_dest, len, second_dest);
stq_u(partial_dest | second_dest, dst+1);
}
checksum += carry;
} else {
unsigned long second, word;
unsigned long second_dest;
err |= __get_user_u(second, lastsrc);
extql(first, soff, word);
extqh(second, soff, first);
word |= first;
ldq_u(second_dest, dst);
mskql(word, len-doff, word);
checksum += word;
mskqh(second_dest, len, second_dest);
carry = checksum < word;
insql(word, doff, word);
stq_u(partial_dest | word | second_dest, dst);
checksum += carry;
}
if (err) *errp = err;
return checksum;
}
static unsigned int
do_csum_partial_copy_from_user(const char *src, char *dst, int len,
unsigned int sum, int *errp)
{
unsigned long checksum = (unsigned) sum;
unsigned long soff = 7 & (unsigned long) src;
unsigned long doff = 7 & (unsigned long) dst;
if (len) {
if (!doff) {
if (!soff)
checksum = csum_partial_cfu_aligned(
(const unsigned long *) src,
(unsigned long *) dst,
len-8, checksum, errp);
else
checksum = csum_partial_cfu_dest_aligned(
(const unsigned long *) src,
(unsigned long *) dst,
soff, len-8, checksum, errp);
} else {
unsigned long partial_dest;
ldq_u(partial_dest, dst);
if (!soff)
checksum = csum_partial_cfu_src_aligned(
(const unsigned long *) src,
(unsigned long *) dst,
doff, len-8, checksum,
partial_dest, errp);
else
checksum = csum_partial_cfu_unaligned(
(const unsigned long *) src,
(unsigned long *) dst,
soff, doff, len-8, checksum,
partial_dest, errp);
}
checksum = from64to16 (checksum);
}
return checksum;
}
unsigned int
csum_partial_copy_from_user(const char *src, char *dst, int len,
unsigned int sum, int *errp)
{
if (!access_ok(src, len, VERIFY_READ)) {
*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 char *src, char *dst, int len, unsigned int sum)
{
return do_csum_partial_copy_from_user(src, dst, len, sum, NULL);
}
unsigned int
csum_partial_copy (const char *src, char *dst, int len, unsigned int sum)
{
unsigned int ret;
int error = 0;
ret = do_csum_partial_copy_from_user(src, dst, len, sum, &error);
if (error)
printk("csum_partial_copy_old(): tell mingo to convert me!\n");
return ret;
}
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