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x86: use the new generic strnlen_user() function

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This throws away the old x86-specific functions in favor of the generic
optimized version.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2012-05-26 11:09:53 -07:00
parent a08c5356a3
commit 5723aa993d
6 changed files with 4 additions and 109 deletions
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1
arch/x86/Kconfig
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@ -94,6 +94,7 @@ config X86
select GENERIC_TIME_VSYSCALL if X86_64
select KTIME_SCALAR if X86_32
select GENERIC_STRNCPY_FROM_USER
select GENERIC_STRNLEN_USER
config INSTRUCTION_DECODER
def_bool (KPROBES || PERF_EVENTS || UPROBES)

3
arch/x86/include/asm/uaccess.h
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@ -566,6 +566,9 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n);
extern __must_check long
strncpy_from_user(char *dst, const char __user *src, long count);
extern __must_check long strlen_user(const char __user *str);
extern __must_check long strnlen_user(const char __user *str, long n);
/*
* movsl can be slow when source and dest are not both 8-byte aligned
*/

17
arch/x86/include/asm/uaccess_32.h
View File

@ -213,23 +213,6 @@ static inline unsigned long __must_check copy_from_user(void *to,
return n;
}
/**
* strlen_user: - Get the size of a string in user space.
* @str: The string to measure.
*
* Context: User context only. This function may sleep.
*
* Get the size of a NUL-terminated string in user space.
*
* Returns the size of the string INCLUDING the terminating NUL.
* On exception, returns 0.
*
* If there is a limit on the length of a valid string, you may wish to
* consider using strnlen_user() instead.
*/
#define strlen_user(str) strnlen_user(str, LONG_MAX)
long strnlen_user(const char __user *str, long n);
unsigned long __must_check clear_user(void __user *mem, unsigned long len);
unsigned long __must_check __clear_user(void __user *mem, unsigned long len);

3
arch/x86/include/asm/uaccess_64.h
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@ -208,9 +208,6 @@ int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
}
}
__must_check long strnlen_user(const char __user *str, long n);
__must_check long __strnlen_user(const char __user *str, long n);
__must_check long strlen_user(const char __user *str);
__must_check unsigned long clear_user(void __user *mem, unsigned long len);
__must_check unsigned long __clear_user(void __user *mem, unsigned long len);

41
arch/x86/lib/usercopy_32.c
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@ -95,47 +95,6 @@ __clear_user(void __user *to, unsigned long n)
}
EXPORT_SYMBOL(__clear_user);
/**
* strnlen_user: - Get the size of a string in user space.
* @s: The string to measure.
* @n: The maximum valid length
*
* Get the size of a NUL-terminated string in user space.
*
* Returns the size of the string INCLUDING the terminating NUL.
* On exception, returns 0.
* If the string is too long, returns a value greater than @n.
*/
long strnlen_user(const char __user *s, long n)
{
unsigned long mask = -__addr_ok(s);
unsigned long res, tmp;
might_fault();
__asm__ __volatile__(
" testl %0, %0\n"
" jz 3f\n"
" andl %0,%%ecx\n"
"0: repne; scasb\n"
" setne %%al\n"
" subl %%ecx,%0\n"
" addl %0,%%eax\n"
"1:\n"
".section .fixup,\"ax\"\n"
"2: xorl %%eax,%%eax\n"
" jmp 1b\n"
"3: movb $1,%%al\n"
" jmp 1b\n"
".previous\n"
_ASM_EXTABLE(0b,2b)
:"=&r" (n), "=&D" (s), "=&a" (res), "=&c" (tmp)
:"0" (n), "1" (s), "2" (0), "3" (mask)
:"cc");
return res & mask;
}
EXPORT_SYMBOL(strnlen_user);
#ifdef CONFIG_X86_INTEL_USERCOPY
static unsigned long
__copy_user_intel(void __user *to, const void *from, unsigned long size)

48
arch/x86/lib/usercopy_64.c
View File

@ -52,54 +52,6 @@ unsigned long clear_user(void __user *to, unsigned long n)
}
EXPORT_SYMBOL(clear_user);
/*
* Return the size of a string (including the ending 0)
*
* Return 0 on exception, a value greater than N if too long
*/
long __strnlen_user(const char __user *s, long n)
{
long res = 0;
char c;
while (1) {
if (res>n)
return n+1;
if (__get_user(c, s))
return 0;
if (!c)
return res+1;
res++;
s++;
}
}
EXPORT_SYMBOL(__strnlen_user);
long strnlen_user(const char __user *s, long n)
{
if (!access_ok(VERIFY_READ, s, 1))
return 0;
return __strnlen_user(s, n);
}
EXPORT_SYMBOL(strnlen_user);
long strlen_user(const char __user *s)
{
long res = 0;
char c;
for (;;) {
if (get_user(c, s))
return 0;
if (!c)
return res+1;
res++;
s++;
}
}
EXPORT_SYMBOL(strlen_user);
unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len)
{
if (access_ok(VERIFY_WRITE, to, len) && access_ok(VERIFY_READ, from, len)) {