1/* 
 2 * User address space access functions.
 3 *
 4 * Copyright 1997 Andi Kleen <ak@muc.de>
 5 * Copyright 1997 Linus Torvalds
 6 * Copyright 2002 Andi Kleen <ak@suse.de>
 7 */
 8#include <linux/module.h>
 9#include <asm/uaccess.h>
10
11/*
12 * Zero Userspace
13 */
14
15unsigned long __clear_user(void __user *addr, unsigned long size)
16{
17	long __d0;
18	might_fault();
19	/* no memory constraint because it doesn't change any memory gcc knows
20	   about */
21	stac();
22	asm volatile(
23		"	testq  %[size8],%[size8]\n"
24		"	jz     4f\n"
25		"0:	movq %[zero],(%[dst])\n"
26		"	addq   %[eight],%[dst]\n"
27		"	decl %%ecx ; jnz   0b\n"
28		"4:	movq  %[size1],%%rcx\n"
29		"	testl %%ecx,%%ecx\n"
30		"	jz     2f\n"
31		"1:	movb   %b[zero],(%[dst])\n"
32		"	incq   %[dst]\n"
33		"	decl %%ecx ; jnz  1b\n"
34		"2:\n"
35		".section .fixup,\"ax\"\n"
36		"3:	lea 0(%[size1],%[size8],8),%[size8]\n"
37		"	jmp 2b\n"
38		".previous\n"
39		_ASM_EXTABLE(0b,3b)
40		_ASM_EXTABLE(1b,2b)
41		: [size8] "=&c"(size), [dst] "=&D" (__d0)
42		: [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr),
43		  [zero] "r" (0UL), [eight] "r" (8UL));
44	clac();
45	return size;
46}
47EXPORT_SYMBOL(__clear_user);
48
49unsigned long clear_user(void __user *to, unsigned long n)
50{
51	if (access_ok(VERIFY_WRITE, to, n))
52		return __clear_user(to, n);
53	return n;
54}
55EXPORT_SYMBOL(clear_user);
56
57unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len)
58{
59	if (access_ok(VERIFY_WRITE, to, len) && access_ok(VERIFY_READ, from, len)) { 
60		return copy_user_generic((__force void *)to, (__force void *)from, len);
61	} 
62	return len;		
63}
64EXPORT_SYMBOL(copy_in_user);
65
66/*
67 * Try to copy last bytes and clear the rest if needed.
68 * Since protection fault in copy_from/to_user is not a normal situation,
69 * it is not necessary to optimize tail handling.
70 */
71__visible unsigned long
72copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest)
73{
74	char c;
75	unsigned zero_len;
76
77	for (; len; --len, to++) {
78		if (__get_user_nocheck(c, from++, sizeof(char)))
79			break;
80		if (__put_user_nocheck(c, to, sizeof(char)))
81			break;
82	}
83
84	for (c = 0, zero_len = len; zerorest && zero_len; --zero_len)
85		if (__put_user_nocheck(c, to++, sizeof(char)))
86			break;
87	clac();
88	return len;
89}

 1/* 
 2 * User address space access functions.
 3 *
 4 * Copyright 1997 Andi Kleen <ak@muc.de>
 5 * Copyright 1997 Linus Torvalds
 6 * Copyright 2002 Andi Kleen <ak@suse.de>
 7 */
 8#include <linux/module.h>
 9#include <asm/uaccess.h>
10
11/*
12 * Zero Userspace
13 */
14
15unsigned long __clear_user(void __user *addr, unsigned long size)
16{
17	long __d0;
18	might_fault();
19	/* no memory constraint because it doesn't change any memory gcc knows
20	   about */
 
21	asm volatile(
22		"	testq  %[size8],%[size8]\n"
23		"	jz     4f\n"
24		"0:	movq %[zero],(%[dst])\n"
25		"	addq   %[eight],%[dst]\n"
26		"	decl %%ecx ; jnz   0b\n"
27		"4:	movq  %[size1],%%rcx\n"
28		"	testl %%ecx,%%ecx\n"
29		"	jz     2f\n"
30		"1:	movb   %b[zero],(%[dst])\n"
31		"	incq   %[dst]\n"
32		"	decl %%ecx ; jnz  1b\n"
33		"2:\n"
34		".section .fixup,\"ax\"\n"
35		"3:	lea 0(%[size1],%[size8],8),%[size8]\n"
36		"	jmp 2b\n"
37		".previous\n"
38		_ASM_EXTABLE(0b,3b)
39		_ASM_EXTABLE(1b,2b)
40		: [size8] "=&c"(size), [dst] "=&D" (__d0)
41		: [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr),
42		  [zero] "r" (0UL), [eight] "r" (8UL));
 
43	return size;
44}
45EXPORT_SYMBOL(__clear_user);
46
47unsigned long clear_user(void __user *to, unsigned long n)
48{
49	if (access_ok(VERIFY_WRITE, to, n))
50		return __clear_user(to, n);
51	return n;
52}
53EXPORT_SYMBOL(clear_user);
54
55unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len)
56{
57	if (access_ok(VERIFY_WRITE, to, len) && access_ok(VERIFY_READ, from, len)) { 
58		return copy_user_generic((__force void *)to, (__force void *)from, len);
59	} 
60	return len;		
61}
62EXPORT_SYMBOL(copy_in_user);
63
64/*
65 * Try to copy last bytes and clear the rest if needed.
66 * Since protection fault in copy_from/to_user is not a normal situation,
67 * it is not necessary to optimize tail handling.
68 */
69unsigned long
70copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest)
71{
72	char c;
73	unsigned zero_len;
74
75	for (; len; --len) {
76		if (__get_user_nocheck(c, from++, sizeof(char)))
77			break;
78		if (__put_user_nocheck(c, to++, sizeof(char)))
79			break;
80	}
81
82	for (c = 0, zero_len = len; zerorest && zero_len; --zero_len)
83		if (__put_user_nocheck(c, to++, sizeof(char)))
84			break;
 
85	return len;
86}