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Commit 5723aa99 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

x86: use the new generic strnlen_user() function 



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

Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a08c5356

arch/x86/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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)

arch/x86/include/asm/uaccess.h

+3 −0
Original line number Diff line number Diff line
@@ -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

 */

arch/x86/include/asm/uaccess_32.h

+0 −17
Original line number Diff line number Diff line
@@ -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);

arch/x86/include/asm/uaccess_64.h

+0 −3
Original line number Diff line number Diff line
@@ -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);

arch/x86/lib/usercopy_32.c

+0 −41
Original line number Diff line number Diff line
@@ -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)