usercopy_32.c

linux 内核源代码

	       "        cmpl $67, %0\n"
	       "        jbe 2f\n"
	       "1:      movl 64(%4), %%eax\n"
	       "        .align 2,0x90\n"
	       "2:      movl 0(%4), %%eax\n"
	       "21:     movl 4(%4), %%edx\n"
	       "        movnti %%eax, 0(%3)\n"
	       "        movnti %%edx, 4(%3)\n"
	       "3:      movl 8(%4), %%eax\n"
	       "31:     movl 12(%4),%%edx\n"
	       "        movnti %%eax, 8(%3)\n"
	       "        movnti %%edx, 12(%3)\n"
	       "4:      movl 16(%4), %%eax\n"
	       "41:     movl 20(%4), %%edx\n"
	       "        movnti %%eax, 16(%3)\n"
	       "        movnti %%edx, 20(%3)\n"
	       "10:     movl 24(%4), %%eax\n"
	       "51:     movl 28(%4), %%edx\n"
	       "        movnti %%eax, 24(%3)\n"
	       "        movnti %%edx, 28(%3)\n"
	       "11:     movl 32(%4), %%eax\n"
	       "61:     movl 36(%4), %%edx\n"
	       "        movnti %%eax, 32(%3)\n"
	       "        movnti %%edx, 36(%3)\n"
	       "12:     movl 40(%4), %%eax\n"
	       "71:     movl 44(%4), %%edx\n"
	       "        movnti %%eax, 40(%3)\n"
	       "        movnti %%edx, 44(%3)\n"
	       "13:     movl 48(%4), %%eax\n"
	       "81:     movl 52(%4), %%edx\n"
	       "        movnti %%eax, 48(%3)\n"
	       "        movnti %%edx, 52(%3)\n"
	       "14:     movl 56(%4), %%eax\n"
	       "91:     movl 60(%4), %%edx\n"
	       "        movnti %%eax, 56(%3)\n"
	       "        movnti %%edx, 60(%3)\n"
	       "        addl $-64, %0\n"
	       "        addl $64, %4\n"
	       "        addl $64, %3\n"
	       "        cmpl $63, %0\n"
	       "        ja  0b\n"
	       "        sfence \n"
	       "5:      movl  %0, %%eax\n"
	       "        shrl  $2, %0\n"
	       "        andl $3, %%eax\n"
	       "        cld\n"
	       "6:      rep; movsl\n"
	       "        movl %%eax,%0\n"
	       "7:      rep; movsb\n"
	       "8:\n"
	       ".section .fixup,\"ax\"\n"
	       "9:      lea 0(%%eax,%0,4),%0\n"
	       "16:     pushl %0\n"
	       "        pushl %%eax\n"
	       "        xorl %%eax,%%eax\n"
	       "        rep; stosb\n"
	       "        popl %%eax\n"
	       "        popl %0\n"
	       "        jmp 8b\n"
	       ".previous\n"
	       ".section __ex_table,\"a\"\n"
	       "	.align 4\n"
	       "	.long 0b,16b\n"
	       "	.long 1b,16b\n"
	       "	.long 2b,16b\n"
	       "	.long 21b,16b\n"
	       "	.long 3b,16b\n"
	       "	.long 31b,16b\n"
	       "	.long 4b,16b\n"
	       "	.long 41b,16b\n"
	       "	.long 10b,16b\n"
	       "	.long 51b,16b\n"
	       "	.long 11b,16b\n"
	       "	.long 61b,16b\n"
	       "	.long 12b,16b\n"
	       "	.long 71b,16b\n"
	       "	.long 13b,16b\n"
	       "	.long 81b,16b\n"
	       "	.long 14b,16b\n"
	       "	.long 91b,16b\n"
	       "	.long 6b,9b\n"
	       "        .long 7b,16b\n"
	       ".previous"
	       : "=&c"(size), "=&D" (d0), "=&S" (d1)
	       :  "1"(to), "2"(from), "0"(size)
	       : "eax", "edx", "memory");
	return size;
}

static unsigned long __copy_user_intel_nocache(void *to,
				const void __user *from, unsigned long size)
{
        int d0, d1;

	__asm__ __volatile__(
	       "        .align 2,0x90\n"
	       "0:      movl 32(%4), %%eax\n"
	       "        cmpl $67, %0\n"
	       "        jbe 2f\n"
	       "1:      movl 64(%4), %%eax\n"
	       "        .align 2,0x90\n"
	       "2:      movl 0(%4), %%eax\n"
	       "21:     movl 4(%4), %%edx\n"
	       "        movnti %%eax, 0(%3)\n"
	       "        movnti %%edx, 4(%3)\n"
	       "3:      movl 8(%4), %%eax\n"
	       "31:     movl 12(%4),%%edx\n"
	       "        movnti %%eax, 8(%3)\n"
	       "        movnti %%edx, 12(%3)\n"
	       "4:      movl 16(%4), %%eax\n"
	       "41:     movl 20(%4), %%edx\n"
	       "        movnti %%eax, 16(%3)\n"
	       "        movnti %%edx, 20(%3)\n"
	       "10:     movl 24(%4), %%eax\n"
	       "51:     movl 28(%4), %%edx\n"
	       "        movnti %%eax, 24(%3)\n"
	       "        movnti %%edx, 28(%3)\n"
	       "11:     movl 32(%4), %%eax\n"
	       "61:     movl 36(%4), %%edx\n"
	       "        movnti %%eax, 32(%3)\n"
	       "        movnti %%edx, 36(%3)\n"
	       "12:     movl 40(%4), %%eax\n"
	       "71:     movl 44(%4), %%edx\n"
	       "        movnti %%eax, 40(%3)\n"
	       "        movnti %%edx, 44(%3)\n"
	       "13:     movl 48(%4), %%eax\n"
	       "81:     movl 52(%4), %%edx\n"
	       "        movnti %%eax, 48(%3)\n"
	       "        movnti %%edx, 52(%3)\n"
	       "14:     movl 56(%4), %%eax\n"
	       "91:     movl 60(%4), %%edx\n"
	       "        movnti %%eax, 56(%3)\n"
	       "        movnti %%edx, 60(%3)\n"
	       "        addl $-64, %0\n"
	       "        addl $64, %4\n"
	       "        addl $64, %3\n"
	       "        cmpl $63, %0\n"
	       "        ja  0b\n"
	       "        sfence \n"
	       "5:      movl  %0, %%eax\n"
	       "        shrl  $2, %0\n"
	       "        andl $3, %%eax\n"
	       "        cld\n"
	       "6:      rep; movsl\n"
	       "        movl %%eax,%0\n"
	       "7:      rep; movsb\n"
	       "8:\n"
	       ".section .fixup,\"ax\"\n"
	       "9:      lea 0(%%eax,%0,4),%0\n"
	       "16:     jmp 8b\n"
	       ".previous\n"
	       ".section __ex_table,\"a\"\n"
	       "	.align 4\n"
	       "	.long 0b,16b\n"
	       "	.long 1b,16b\n"
	       "	.long 2b,16b\n"
	       "	.long 21b,16b\n"
	       "	.long 3b,16b\n"
	       "	.long 31b,16b\n"
	       "	.long 4b,16b\n"
	       "	.long 41b,16b\n"
	       "	.long 10b,16b\n"
	       "	.long 51b,16b\n"
	       "	.long 11b,16b\n"
	       "	.long 61b,16b\n"
	       "	.long 12b,16b\n"
	       "	.long 71b,16b\n"
	       "	.long 13b,16b\n"
	       "	.long 81b,16b\n"
	       "	.long 14b,16b\n"
	       "	.long 91b,16b\n"
	       "	.long 6b,9b\n"
	       "        .long 7b,16b\n"
	       ".previous"
	       : "=&c"(size), "=&D" (d0), "=&S" (d1)
	       :  "1"(to), "2"(from), "0"(size)
	       : "eax", "edx", "memory");
	return size;
}

#else

/*
 * Leave these declared but undefined.  They should not be any references to
 * them
 */
unsigned long __copy_user_zeroing_intel(void *to, const void __user *from,
					unsigned long size);
unsigned long __copy_user_intel(void __user *to, const void *from,
					unsigned long size);
unsigned long __copy_user_zeroing_intel_nocache(void *to,
				const void __user *from, unsigned long size);
#endif /* CONFIG_X86_INTEL_USERCOPY */

/* Generic arbitrary sized copy.  */
#define __copy_user(to,from,size)					\
do {									\
	int __d0, __d1, __d2;						\
	__asm__ __volatile__(						\
		"	cmp  $7,%0\n"					\
		"	jbe  1f\n"					\
		"	movl %1,%0\n"					\
		"	negl %0\n"					\
		"	andl $7,%0\n"					\
		"	subl %0,%3\n"					\
		"4:	rep; movsb\n"					\
		"	movl %3,%0\n"					\
		"	shrl $2,%0\n"					\
		"	andl $3,%3\n"					\
		"	.align 2,0x90\n"				\
		"0:	rep; movsl\n"					\
		"	movl %3,%0\n"					\
		"1:	rep; movsb\n"					\
		"2:\n"							\
		".section .fixup,\"ax\"\n"				\
		"5:	addl %3,%0\n"					\
		"	jmp 2b\n"					\
		"3:	lea 0(%3,%0,4),%0\n"				\
		"	jmp 2b\n"					\
		".previous\n"						\
		".section __ex_table,\"a\"\n"				\
		"	.align 4\n"					\
		"	.long 4b,5b\n"					\
		"	.long 0b,3b\n"					\
		"	.long 1b,2b\n"					\
		".previous"						\
		: "=&c"(size), "=&D" (__d0), "=&S" (__d1), "=r"(__d2)	\
		: "3"(size), "0"(size), "1"(to), "2"(from)		\
		: "memory");						\
} while (0)

#define __copy_user_zeroing(to,from,size)				\
do {									\
	int __d0, __d1, __d2;						\
	__asm__ __volatile__(						\
		"	cmp  $7,%0\n"					\
		"	jbe  1f\n"					\
		"	movl %1,%0\n"					\
		"	negl %0\n"					\
		"	andl $7,%0\n"					\
		"	subl %0,%3\n"					\
		"4:	rep; movsb\n"					\
		"	movl %3,%0\n"					\
		"	shrl $2,%0\n"					\
		"	andl $3,%3\n"					\
		"	.align 2,0x90\n"				\
		"0:	rep; movsl\n"					\
		"	movl %3,%0\n"					\
		"1:	rep; movsb\n"					\
		"2:\n"							\
		".section .fixup,\"ax\"\n"				\
		"5:	addl %3,%0\n"					\
		"	jmp 6f\n"					\
		"3:	lea 0(%3,%0,4),%0\n"				\
		"6:	pushl %0\n"					\
		"	pushl %%eax\n"					\
		"	xorl %%eax,%%eax\n"				\
		"	rep; stosb\n"					\
		"	popl %%eax\n"					\
		"	popl %0\n"					\
		"	jmp 2b\n"					\
		".previous\n"						\
		".section __ex_table,\"a\"\n"				\
		"	.align 4\n"					\
		"	.long 4b,5b\n"					\
		"	.long 0b,3b\n"					\
		"	.long 1b,6b\n"					\
		".previous"						\
		: "=&c"(size), "=&D" (__d0), "=&S" (__d1), "=r"(__d2)	\
		: "3"(size), "0"(size), "1"(to), "2"(from)		\
		: "memory");						\
} while (0)

unsigned long __copy_to_user_ll(void __user *to, const void *from,
				unsigned long n)
{
#ifndef CONFIG_X86_WP_WORKS_OK
	if (unlikely(boot_cpu_data.wp_works_ok == 0) &&
			((unsigned long )to) < TASK_SIZE) {
		/*
		 * When we are in an atomic section (see
		 * mm/filemap.c:file_read_actor), return the full
		 * length to take the slow path.
		 */
		if (in_atomic())
			return n;

		/* 
		 * CPU does not honor the WP bit when writing
		 * from supervisory mode, and due to preemption or SMP,
		 * the page tables can change at any time.
		 * Do it manually.	Manfred <[e-mail]>
		 */
		while (n) {
		      	unsigned long offset = ((unsigned long)to)%PAGE_SIZE;
			unsigned long len = PAGE_SIZE - offset;
			int retval;
			struct page *pg;
			void *maddr;
			
			if (len > n)
				len = n;

survive:
			down_read(&current->mm->mmap_sem);
			retval = get_user_pages(current, current->mm,
					(unsigned long )to, 1, 1, 0, &pg, NULL);

			if (retval == -ENOMEM && is_global_init(current)) {
				up_read(&current->mm->mmap_sem);
				congestion_wait(WRITE, HZ/50);
				goto survive;
			}

			if (retval != 1) {
				up_read(&current->mm->mmap_sem);
		       		break;
		       	}

			maddr = kmap_atomic(pg, KM_USER0);
			memcpy(maddr + offset, from, len);
			kunmap_atomic(maddr, KM_USER0);
			set_page_dirty_lock(pg);
			put_page(pg);
			up_read(&current->mm->mmap_sem);

			from += len;
			to += len;
			n -= len;
		}
		return n;
	}
#endif
	if (movsl_is_ok(to, from, n))
		__copy_user(to, from, n);
	else
		n = __copy_user_intel(to, from, n);
	return n;
}
EXPORT_SYMBOL(__copy_to_user_ll);

unsigned long __copy_from_user_ll(void *to, const void __user *from,
					unsigned long n)
{
	if (movsl_is_ok(to, from, n))
		__copy_user_zeroing(to, from, n);
	else
		n = __copy_user_zeroing_intel(to, from, n);
	return n;
}
EXPORT_SYMBOL(__copy_from_user_ll);

unsigned long __copy_from_user_ll_nozero(void *to, const void __user *from,
					 unsigned long n)
{
	if (movsl_is_ok(to, from, n))
		__copy_user(to, from, n);
	else
		n = __copy_user_intel((void __user *)to,
				      (const void *)from, n);
	return n;
}
EXPORT_SYMBOL(__copy_from_user_ll_nozero);

unsigned long __copy_from_user_ll_nocache(void *to, const void __user *from,
					unsigned long n)
{
#ifdef CONFIG_X86_INTEL_USERCOPY
	if ( n > 64 && cpu_has_xmm2)
                n = __copy_user_zeroing_intel_nocache(to, from, n);
	else
		__copy_user_zeroing(to, from, n);
#else
        __copy_user_zeroing(to, from, n);
#endif
	return n;
}

unsigned long __copy_from_user_ll_nocache_nozero(void *to, const void __user *from,
					unsigned long n)
{
#ifdef CONFIG_X86_INTEL_USERCOPY
	if ( n > 64 && cpu_has_xmm2)
                n = __copy_user_intel_nocache(to, from, n);
	else
		__copy_user(to, from, n);
#else
        __copy_user(to, from, n);
#endif
	return n;
}

/**
 * copy_to_user: - Copy a block of data into user space.
 * @to:   Destination address, in user space.
 * @from: Source address, in kernel space.
 * @n:    Number of bytes to copy.
 *
 * Context: User context only.  This function may sleep.
 *
 * Copy data from kernel space to user space.
 *
 * Returns number of bytes that could not be copied.
 * On success, this will be zero.
 */
unsigned long
copy_to_user(void __user *to, const void *from, unsigned long n)
{
	if (access_ok(VERIFY_WRITE, to, n))
		n = __copy_to_user(to, from, n);
	return n;
}
EXPORT_SYMBOL(copy_to_user);

/**
 * copy_from_user: - Copy a block of data from user space.
 * @to:   Destination address, in kernel space.
 * @from: Source address, in user space.
 * @n:    Number of bytes to copy.
 *
 * Context: User context only.  This function may sleep.
 *
 * Copy data from user space to kernel space.
 *
 * Returns number of bytes that could not be copied.
 * On success, this will be zero.
 *
 * If some data could not be copied, this function will pad the copied
 * data to the requested size using zero bytes.
 */
unsigned long
copy_from_user(void *to, const void __user *from, unsigned long n)
{
	if (access_ok(VERIFY_READ, from, n))
		n = __copy_from_user(to, from, n);
	else
		memset(to, 0, n);
	return n;
}
EXPORT_SYMBOL(copy_from_user);