/* * include/asm-xtensa/uaccess.h * * User space memory access functions * * These routines provide basic accessing functions to the user memory * space for the kernel. This header file provides fuctions such as: * * This file is subject to the terms and conditions of the GNU General Public * License.  See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 2001 - 2005 Tensilica Inc. */ #ifndef _XTENSA_UACCESS_H#define _XTENSA_UACCESS_H #include <linux/errno.h> #define VERIFY_READ    0#define VERIFY_WRITE   1 #ifdef __ASSEMBLY__ #define _ASMLANGUAGE#include <asm/current.h>#include <asm/asm-offsets.h>#include <asm/processor.h> /* * These assembly macros mirror the C macros that follow below.  They * should always have identical functionality.  See * arch/xtensa/kernel/sys.S for usage. */ #define KERNEL_DS	0#define USER_DS		1 #define get_ds		(KERNEL_DS) /* * get_fs reads current->thread.current_ds into a register. * On Entry: * 	<ad>	anything * 	<sp>	stack * On Exit: * 	<ad>	contains current->thread.current_ds */	.macro	get_fs	ad, sp	GET_CURRENT(\ad,\sp)	l32i	\ad, \ad, THREAD_CURRENT_DS	.endm /* * set_fs sets current->thread.current_ds to some value. * On Entry: *	<at>	anything (temp register) *	<av>	value to write *	<sp>	stack * On Exit: *	<at>	destroyed (actually, current) *	<av>	preserved, value to write */	.macro	set_fs	at, av, sp	GET_CURRENT(\at,\sp)	s32i	\av, \at, THREAD_CURRENT_DS	.endm /* * kernel_ok determines whether we should bypass addr/size checking. * See the equivalent C-macro version below for clarity. * On success, kernel_ok branches to a label indicated by parameter * <success>.  This implies that the macro falls through to the next * insruction on an error. * * Note that while this macro can be used independently, we designed * in for optimal use in the access_ok macro below (i.e., we fall * through on error). * * On Entry: * 	<at>		anything (temp register) * 	<success>	label to branch to on success; implies * 			fall-through macro on error * 	<sp>		stack pointer * On Exit: * 	<at>		destroyed (actually, current->thread.current_ds) */ #if ((KERNEL_DS != 0) || (USER_DS == 0))# error Assembly macro kernel_ok fails#endif	.macro	kernel_ok  at, sp, success	get_fs	\at, \sp	beqz	\at, \success	.endm /* * user_ok determines whether the access to user-space memory is allowed. * See the equivalent C-macro version below for clarity. * * On error, user_ok branches to a label indicated by parameter * <error>.  This implies that the macro falls through to the next * instruction on success. * * Note that while this macro can be used independently, we designed * in for optimal use in the access_ok macro below (i.e., we fall * through on success). * * On Entry: * 	<aa>	register containing memory address * 	<as>	register containing memory size * 	<at>	temp register * 	<error>	label to branch to on error; implies fall-through * 		macro on success * On Exit: * 	<aa>	preserved * 	<as>	preserved * 	<at>	destroyed (actually, (TASK_SIZE + 1 - size)) */	.macro	user_ok	aa, as, at, error	movi	\at, (TASK_SIZE+1)	bgeu	\as, \at, \error	sub	\at, \at, \as	bgeu	\aa, \at, \error	.endm /* * access_ok determines whether a memory access is allowed.  See the * equivalent C-macro version below for clarity. * * On error, access_ok branches to a label indicated by parameter * <error>.  This implies that the macro falls through to the next * instruction on success. * * Note that we assume success is the common case, and we optimize the * branch fall-through case on success. * * On Entry: * 	<aa>	register containing memory address * 	<as>	register containing memory size * 	<at>	temp register * 	<sp> * 	<error>	label to branch to on error; implies fall-through * 		macro on success * On Exit: * 	<aa>	preserved * 	<as>	preserved * 	<at>	destroyed */	.macro	access_ok  aa, as, at, sp, error	kernel_ok  \at, \sp, .Laccess_ok_\@	user_ok    \aa, \as, \at, \error.Laccess_ok_\@:	.endm /* * verify_area determines whether a memory access is allowed.  It's * mostly an unnecessary wrapper for access_ok, but we provide it as a * duplicate of the verify_area() C inline function below.  See the * equivalent C version below for clarity. * * On error, verify_area branches to a label indicated by parameter * <error>.  This implies that the macro falls through to the next * instruction on success. * * Note that we assume success is the common case, and we optimize the * branch fall-through case on success. * * On Entry: * 	<aa>	register containing memory address * 	<as>	register containing memory size * 	<at>	temp register * 	<error>	label to branch to on error; implies fall-through * 		macro on success * On Exit: * 	<aa>	preserved * 	<as>	preserved * 	<at>	destroyed */	.macro	verify_area	aa, as, at, sp, error	access_ok  \at, \aa, \as, \sp, \error	.endm  #else /* __ASSEMBLY__ not defined */ #include <linux/sched.h>#include <asm/types.h> /* * The fs value determines whether argument validity checking should * be performed or not.  If get_fs() == USER_DS, checking is * performed, with get_fs() == KERNEL_DS, checking is bypassed. * * For historical reasons (Data Segment Register?), these macros are * grossly misnamed. */ #define KERNEL_DS	((mm_segment_t) { 0 })#define USER_DS		((mm_segment_t) { 1 }) #define get_ds()	(KERNEL_DS)#define get_fs()	(current->thread.current_ds)#define set_fs(val)	(current->thread.current_ds = (val)) #define segment_eq(a,b)	((a).seg == (b).seg) #define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))#define __user_ok(addr,size) (((size) <= TASK_SIZE)&&((addr) <= TASK_SIZE-(size)))#define __access_ok(addr,size) (__kernel_ok || __user_ok((addr),(size)))#define access_ok(type,addr,size) __access_ok((unsigned long)(addr),(size)) static inline int verify_area(int type, const void * addr, unsigned long size){	return access_ok(type,addr,size) ? 0 : -EFAULT;} /* * These are the main single-value transfer routines.  They * automatically use the right size if we just have the right pointer * type. * * This gets kind of ugly. We want to return _two_ values in * "get_user()" and yet we don't want to do any pointers, because that * is too much of a performance impact. Thus we have a few rather ugly * macros here, and hide all the uglyness from the user. * * Careful to not * (a) re-use the arguments for side effects (sizeof is ok) * (b) require any knowledge of processes at this stage */#define put_user(x,ptr)	__put_user_check((x),(ptr),sizeof(*(ptr)))#define get_user(x,ptr) __get_user_check((x),(ptr),sizeof(*(ptr))) /* * The "__xxx" versions of the user access functions are versions that * do not verify the address space, that must have been done previously * with a separate "access_ok()" call (this is used when we do multiple * accesses to the same area of user memory). */#define __put_user(x,ptr) __put_user_nocheck((x),(ptr),sizeof(*(ptr)))#define __get_user(x,ptr) __get_user_nocheck((x),(ptr),sizeof(*(ptr)))  extern long __put_user_bad(void); #define __put_user_nocheck(x,ptr,size)			\({							\	long __pu_err;					\	__put_user_size((x),(ptr),(size),__pu_err);	\	__pu_err;					\}) #define __put_user_check(x,ptr,size)				\({								\	long __pu_err = -EFAULT;				\	__typeof__(*(ptr)) *__pu_addr = (ptr);			\	if (access_ok(VERIFY_WRITE,__pu_addr,size))		\		__put_user_size((x),__pu_addr,(size),__pu_err);	\	__pu_err;						\}) #define __put_user_size(x,ptr,size,retval)			\do {								\	retval = 0;						\	switch (size) {						\        case 1: __put_user_asm(x,ptr,retval,1,"s8i");  break;	\        case 2: __put_user_asm(x,ptr,retval,2,"s16i"); break;   \        case 4: __put_user_asm(x,ptr,retval,4,"s32i"); break;   \        case 8: {						\		     __typeof__(*ptr) __v64 = x;		\		     retval = __copy_to_user(ptr,&__v64,8);	\		     break;					\	        }						\	default: __put_user_bad();				\	}							\} while (0)  /* * Consider a case of a user single load/store would cause both an * unaligned exception and an MMU-related exception (unaligned * exceptions happen first): * * User code passes a bad variable ptr to a system call. * Kernel tries to access the variable. * Unaligned exception occurs. * Unaligned exception handler tries to make aligned accesses. * Double exception occurs for MMU-related cause (e.g., page not mapped). * do_page_fault() thinks the fault address belongs to the kernel, not the * user, and panics. * * The kernel currently prohibits user unaligned accesses.  We use the * __check_align_* macros to check for unaligned addresses before * accessing user space so we don't crash the kernel.  Both * __put_user_asm and __get_user_asm use these alignment macros, so * macro-specific labels such as 0f, 1f, %0, %2, and %3 must stay in * sync. */ #define __check_align_1  "" #define __check_align_2				\	"   _bbci.l %2,  0, 1f		\n"	\	"   movi    %0, %3		\n"	\	"   _j      2f			\n" #define __check_align_4				\	"   _bbsi.l %2,  0, 0f		\n"	\	"   _bbci.l %2,  1, 1f		\n"	\	"0: movi    %0, %3		\n"	\	"   _j      2f			\n"  /* * We don't tell gcc that we are accessing memory, but this is OK * because we do not write to any memory gcc knows about, so there * are no aliasing issues. * * WARNING: If you modify this macro at all, verify that the * __check_align_* macros still work. */#define __put_user_asm(x, addr, err, align, insn) \   __asm__ __volatile__(			\	__check_align_##align			\	"1: "insn"  %1, %2, 0		\n"	\	"2:				\n"	\	"   .section  .fixup,\"ax\"	\n"	\	"   .align 4			\n"	\	"4:				\n"	\	"   .long  2b			\n"	\	"5:				\n"	\	"   l32r   %2, 4b		\n"	\        "   movi   %0, %3		\n"	\        "   jx     %2			\n"	\	"   .previous			\n"	\	"   .section  __ex_table,\"a\"	\n"	\	"   .long	1b, 5b		\n"	\	"   .previous"				\	:"=r" (err)				\	:"r" ((int)(x)), "r" (addr), "i" (-EFAULT), "0" (err)) #define __get_user_nocheck(x,ptr,size)				\({								\	long __gu_err, __gu_val;				\	__get_user_size(__gu_val,(ptr),(size),__gu_err);	\	(x) = (__typeof__(*(ptr)))__gu_val;			\	__gu_err;						\}) #define __get_user_check(x,ptr,size)					\({									\	long __gu_err = -EFAULT, __gu_val = 0;				\	const __typeof__(*(ptr)) *__gu_addr = (ptr);			\	if (access_ok(VERIFY_READ,__gu_addr,size))			\		__get_user_size(__gu_val,__gu_addr,(size),__gu_err);	\	(x) = (__typeof__(*(ptr)))__gu_val;				\	__gu_err;							\}) extern long __get_user_bad(void); #define __get_user_size(x,ptr,size,retval)				\do {									\	retval = 0;							\        switch (size) {							\          case 1: __get_user_asm(x,ptr,retval,1,"l8ui");  break;	\          case 2: __get_user_asm(x,ptr,retval,2,"l16ui"); break;	\          case 4: __get_user_asm(x,ptr,retval,4,"l32i");  break;	\          case 8: retval = __copy_from_user(&x,ptr,8);    break;	\          default: (x) = __get_user_bad();				\        }								\} while (0)  /* * WARNING: If you modify this macro at all, verify that the * __check_align_* macros still work. */#define __get_user_asm(x, addr, err, align, insn) \   __asm__ __volatile__(			\	__check_align_##align			\	"1: "insn"  %1, %2, 0		\n"	\	"2:				\n"	\	"   .section  .fixup,\"ax\"	\n"	\	"   .align 4			\n"	\	"4:				\n"	\	"   .long  2b			\n"	\	"5:				\n"	\	"   l32r   %2, 4b		\n"	\	"   movi   %1, 0		\n"	\        "   movi   %0, %3		\n"	\        "   jx     %2			\n"	\	"   .previous			\n"	\	"   .section  __ex_table,\"a\"	\n"	\	"   .long	1b, 5b		\n"	\	"   .previous"				\	:"=r" (err), "=r" (x)			\	:"r" (addr), "i" (-EFAULT), "0" (err))  /* * Copy to/from user space */ /* * We use a generic, arbitrary-sized copy subroutine.  The Xtensa * architecture would cause heavy code bloat if we tried to inline * these functions and provide __constant_copy_* equivalents like the * i386 versions.  __xtensa_copy_user is quite efficient.  See the * .fixup section of __xtensa_copy_user for a discussion on the * X_zeroing equivalents for Xtensa. */ extern unsigned __xtensa_copy_user(void *to, const void *from, unsigned n);#define __copy_user(to,from,size) __xtensa_copy_user(to,from,size)  static inline unsigned long__generic_copy_from_user_nocheck(void *to, const void *from, unsigned long n){	return __copy_user(to,from,n);} static inline unsigned long__generic_copy_to_user_nocheck(void *to, const void *from, unsigned long n){	return __copy_user(to,from,n);} static inline unsigned long__generic_copy_to_user(void *to, const void *from, unsigned long n){	prefetch(from);	if (access_ok(VERIFY_WRITE, to, n))		return __copy_user(to,from,n);	return n;} static inline unsigned long__generic_copy_from_user(void *to, const void *from, unsigned long n){	prefetchw(to);	if (access_ok(VERIFY_READ, from, n))		return __copy_user(to,from,n);	else		memset(to, 0, n);	return n;} #define copy_to_user(to,from,n) __generic_copy_to_user((to),(from),(n))#define copy_from_user(to,from,n) __generic_copy_from_user((to),(from),(n))#define __copy_to_user(to,from,n) __generic_copy_to_user_nocheck((to),(from),(n))#define __copy_from_user(to,from,n) __generic_copy_from_user_nocheck((to),(from),(n))#define __copy_to_user_inatomic __copy_to_user#define __copy_from_user_inatomic __copy_from_user  /* * We need to return the number of bytes not cleared.  Our memset() * returns zero if a problem occurs while accessing user-space memory. * In that event, return no memory cleared.  Otherwise, zero for * success. */ static inline unsigned long__xtensa_clear_user(void *addr, unsigned long size){	if ( ! memset(addr, 0, size) )		return size;	return 0;} static inline unsigned longclear_user(void *addr, unsigned long size){	if (access_ok(VERIFY_WRITE, addr, size))		return __xtensa_clear_user(addr, size);	return size ? -EFAULT : 0;} #define __clear_user  __xtensa_clear_user  extern long __strncpy_user(char *, const char *, long);#define __strncpy_from_user __strncpy_user static inline longstrncpy_from_user(char *dst, const char *src, long count){	if (access_ok(VERIFY_READ, src, 1))		return __strncpy_from_user(dst, src, count);	return -EFAULT;}  #define strlen_user(str) strnlen_user((str), TASK_SIZE - 1) /*

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