uaccess.h

来自「Linux Kernel 2.6.9 for OMAP1710」· C头文件 代码 · 共 826 行 · 第 1/2 页

/*
 * 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) 1996, 1997, 1998, 1999, 2000, 03, 04 by Ralf Baechle
 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
 */
#ifndef _ASM_UACCESS_H
#define _ASM_UACCESS_H

#include <linux/config.h>
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/thread_info.h>
#include <asm-generic/uaccess.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, these macros are grossly misnamed.
 */
#ifdef CONFIG_MIPS32

#define __UA_LIMIT	0x80000000UL

#define __UA_ADDR	".word"
#define __UA_LA		"la"
#define __UA_ADDU	"addu"
#define __UA_t0		"$8"
#define __UA_t1		"$9"

#endif /* CONFIG_MIPS32 */

#ifdef CONFIG_MIPS64

#define __UA_LIMIT	(- TASK_SIZE)

#define __UA_ADDR	".dword"
#define __UA_LA		"dla"
#define __UA_ADDU	"daddu"
#define __UA_t0		"$12"
#define __UA_t1		"$13"

#endif /* CONFIG_MIPS64 */

/*
 * USER_DS is a bitmask that has the bits set that may not be set in a valid
 * userspace address.  Note that we limit 32-bit userspace to 0x7fff8000 but
 * the arithmetic we're doing only works if the limit is a power of two, so
 * we use 0x80000000 here on 32-bit kernels.  If a process passes an invalid
 * address in this range it's the process's problem, not ours :-)
 */

#define KERNEL_DS	((mm_segment_t) { 0UL })
#define USER_DS		((mm_segment_t) { __UA_LIMIT })

#define VERIFY_READ    0
#define VERIFY_WRITE   1

#define get_ds()	(KERNEL_DS)
#define get_fs()	(current_thread_info()->addr_limit)
#define set_fs(x)	(current_thread_info()->addr_limit = (x))

#define segment_eq(a,b)	((a).seg == (b).seg)


/*
 * Is a address valid? This does a straighforward calculation rather
 * than tests.
 *
 * Address valid if:
 *  - "addr" doesn't have any high-bits set
 *  - AND "size" doesn't have any high-bits set
 *  - AND "addr+size" doesn't have any high-bits set
 *  - OR we are in kernel mode.
 *
 * __ua_size() is a trick to avoid runtime checking of positive constant
 * sizes; for those we already know at compile time that the size is ok.
 */
#define __ua_size(size)							\
	((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size))

/*
 * access_ok: - Checks if a user space pointer is valid
 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
 *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
 *        to write to a block, it is always safe to read from it.
 * @addr: User space pointer to start of block to check
 * @size: Size of block to check
 *
 * Context: User context only.  This function may sleep.
 *
 * Checks if a pointer to a block of memory in user space is valid.
 *
 * Returns true (nonzero) if the memory block may be valid, false (zero)
 * if it is definitely invalid.
 *
 * Note that, depending on architecture, this function probably just
 * checks that the pointer is in the user space range - after calling
 * this function, memory access functions may still return -EFAULT.
 */

#define __access_mask get_fs().seg

#define __access_ok(addr, size, mask)					\
	(((signed long)((mask) & ((addr) | ((addr) + (size)) | __ua_size(size)))) == 0)

#define access_ok(type, addr, size)					\
	likely(__access_ok((unsigned long)(addr), (size),__access_mask))

/*
 * verify_area: - Obsolete, use access_ok()
 * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE
 * @addr: User space pointer to start of block to check
 * @size: Size of block to check
 *
 * Context: User context only.  This function may sleep.
 *
 * This function has been replaced by access_ok().
 *
 * Checks if a pointer to a block of memory in user space is valid.
 *
 * Returns zero if the memory block may be valid, -EFAULT
 * if it is definitely invalid.
 *
 * See access_ok() for more details.
 */
static inline int verify_area(int type, const void * addr, unsigned long size)
{
	return access_ok(type, addr, size) ? 0 : -EFAULT;
}

/*
 * put_user: - Write a simple value into user space.
 * @x:   Value to copy to user space.
 * @ptr: Destination address, in user space.
 *
 * Context: User context only.  This function may sleep.
 *
 * This macro copies a single simple value from kernel space to user
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 * to the result of dereferencing @ptr.
 *
 * Returns zero on success, or -EFAULT on error.
 */
#define put_user(x,ptr)	\
	__put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))

/*
 * get_user: - Get a simple variable from user space.
 * @x:   Variable to store result.
 * @ptr: Source address, in user space.
 *
 * Context: User context only.  This function may sleep.
 *
 * This macro copies a single simple variable from user space to kernel
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and the result of
 * dereferencing @ptr must be assignable to @x without a cast.
 *
 * Returns zero on success, or -EFAULT on error.
 * On error, the variable @x is set to zero.
 */
#define get_user(x,ptr) \
	__get_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))

/*
 * __put_user: - Write a simple value into user space, with less checking.
 * @x:   Value to copy to user space.
 * @ptr: Destination address, in user space.
 *
 * Context: User context only.  This function may sleep.
 *
 * This macro copies a single simple value from kernel space to user
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 * to the result of dereferencing @ptr.
 *
 * Caller must check the pointer with access_ok() before calling this
 * function.
 *
 * Returns zero on success, or -EFAULT on error.
 */
#define __put_user(x,ptr) \
	__put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))

/*
 * __get_user: - Get a simple variable from user space, with less checking.
 * @x:   Variable to store result.
 * @ptr: Source address, in user space.
 *
 * Context: User context only.  This function may sleep.
 *
 * This macro copies a single simple variable from user space to kernel
 * space.  It supports simple types like char and int, but not larger
 * data types like structures or arrays.
 *
 * @ptr must have pointer-to-simple-variable type, and the result of
 * dereferencing @ptr must be assignable to @x without a cast.
 *
 * Caller must check the pointer with access_ok() before calling this
 * function.
 *
 * Returns zero on success, or -EFAULT on error.
 * On error, the variable @x is set to zero.
 */
#define __get_user(x,ptr) \
	__get_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))

struct __large_struct { unsigned long buf[100]; };
#define __m(x) (*(struct __large_struct *)(x))

/*
 * Yuck.  We need two variants, one for 64bit operation and one
 * for 32 bit mode and old iron.
 */
#ifdef __mips64
#define __GET_USER_DW __get_user_asm("ld")
#else
#define __GET_USER_DW __get_user_asm_ll32
#endif

#define __get_user_nocheck(x,ptr,size)				\
({								\
	long __gu_err;						\
	__typeof(*(ptr)) __gu_val;				\
	long __gu_addr;						\
	might_sleep();						\
	__asm__("":"=r" (__gu_val));				\
	__gu_addr = (long) (ptr);				\
	__asm__("":"=r" (__gu_err));				\
	switch (size) {						\
	case 1: __get_user_asm("lb"); break;			\
	case 2: __get_user_asm("lh"); break;			\
	case 4: __get_user_asm("lw"); break;			\
	case 8: __GET_USER_DW; break;				\
	default: __get_user_unknown(); break;			\
	} x = (__typeof__(*(ptr))) __gu_val; __gu_err;		\
})

#define __get_user_check(x,ptr,size)					\
({									\
	long __gu_err;							\
	__typeof__(*(ptr)) __gu_val;					\
	long __gu_addr;							\
	might_sleep();							\
	__asm__("":"=r" (__gu_val));					\
	__gu_addr = (long) (ptr);					\
	__asm__("":"=r" (__gu_err));					\
	if (access_ok(VERIFY_READ,__gu_addr,size)) {			\
		switch (size) {						\
		case 1: __get_user_asm("lb"); break;			\
		case 2: __get_user_asm("lh"); break;			\
		case 4: __get_user_asm("lw"); break;			\
		case 8: __GET_USER_DW; break;				\
		default: __get_user_unknown(); break;			\
		}							\
	} x = (__typeof__(*(ptr))) __gu_val; __gu_err;			\
})

#define __get_user_asm(insn)						\
({									\
	__asm__ __volatile__(						\
	"1:\t" insn "\t%1,%2\n\t"					\
	"move\t%0,$0\n"							\
	"2:\n\t"							\
	".section\t.fixup,\"ax\"\n"					\
	"3:\tli\t%0,%3\n\t"						\
	"move\t%1,$0\n\t"						\
	"j\t2b\n\t"							\
	".previous\n\t"							\
	".section\t__ex_table,\"a\"\n\t"				\
	__UA_ADDR "\t1b,3b\n\t"						\
	".previous"							\
	:"=r" (__gu_err), "=r" (__gu_val)				\
	:"o" (__m(__gu_addr)), "i" (-EFAULT));				\
})

/*
 * Get a long long 64 using 32 bit registers.
 */
#define __get_user_asm_ll32						\
({									\
	__asm__ __volatile__(						\
	"1:\tlw\t%1,%2\n"						\
	"2:\tlw\t%D1,%3\n\t"						\
	"move\t%0,$0\n"							\
	"3:\t.section\t.fixup,\"ax\"\n"					\
	"4:\tli\t%0,%4\n\t"						\
	"move\t%1,$0\n\t"						\
	"move\t%D1,$0\n\t"						\
	"j\t3b\n\t"							\
	".previous\n\t"							\
	".section\t__ex_table,\"a\"\n\t"				\
	__UA_ADDR "\t1b,4b\n\t"						\
	__UA_ADDR "\t2b,4b\n\t"						\
	".previous"							\
	:"=r" (__gu_err), "=&r" (__gu_val)				\
	:"o" (__m(__gu_addr)), "o" (__m(__gu_addr + 4)),		\
	 "i" (-EFAULT));						\
})

extern void __get_user_unknown(void);

/*
 * Yuck.  We need two variants, one for 64bit operation and one
 * for 32 bit mode and old iron.
 */
#ifdef __mips64
#define __PUT_USER_DW __put_user_asm("sd")
#else
#define __PUT_USER_DW __put_user_asm_ll32
#endif

#define __put_user_nocheck(x,ptr,size)					\
({									\
	long __pu_err;							\
	__typeof__(*(ptr)) __pu_val;					\
	long __pu_addr;							\
	might_sleep();							\
	__pu_val = (x);							\
	__pu_addr = (long) (ptr);					\
	__asm__("":"=r" (__pu_err));					\
	switch (size) {							\
	case 1: __put_user_asm("sb"); break;				\
	case 2: __put_user_asm("sh"); break;				\
	case 4: __put_user_asm("sw"); break;				\
	case 8: __PUT_USER_DW; break;					\
	default: __put_user_unknown(); break;				\
	}								\
	__pu_err;							\
})

#define __put_user_check(x,ptr,size)					\
({									\
	long __pu_err;							\
	__typeof__(*(ptr)) __pu_val;					\
	long __pu_addr;							\
	might_sleep();							\
	__pu_val = (x);							\
	__pu_addr = (long) (ptr);					\
	__asm__("":"=r" (__pu_err));					\
	if (access_ok(VERIFY_WRITE, __pu_addr, size)) {			\
		switch (size) {						\
		case 1: __put_user_asm("sb"); break;			\
		case 2: __put_user_asm("sh"); break;			\
		case 4: __put_user_asm("sw"); break;			\
		case 8: __PUT_USER_DW; break;				\
		default: __put_user_unknown(); break;			\
		}							\
	}								\
	__pu_err;							\
})

#define __put_user_asm(insn)						\
({									\
	__asm__ __volatile__(						\
	"1:\t" insn "\t%z1, %2\t\t\t# __put_user_asm\n\t"		\
	"move\t%0, $0\n"						\
	"2:\n\t"							\
	".section\t.fixup,\"ax\"\n"					\
	"3:\tli\t%0,%3\n\t"						\
	"j\t2b\n\t"							\
	".previous\n\t"							\
	".section\t__ex_table,\"a\"\n\t"				\
	__UA_ADDR "\t1b,3b\n\t"						\
	".previous"							\
	:"=r" (__pu_err)						\
	:"Jr" (__pu_val), "o" (__m(__pu_addr)), "i" (-EFAULT));		\
})

#define __put_user_asm_ll32						\
({									\
	__asm__ __volatile__(						\
	"1:\tsw\t%1, %2\t\t\t# __put_user_asm_ll32\n\t"			\
	"2:\tsw\t%D1, %3\n"						\
	"move\t%0, $0\n"						\
	"3:\n\t"							\
	".section\t.fixup,\"ax\"\n"					\
	"4:\tli\t%0,%4\n\t"						\
	"j\t3b\n\t"							\
	".previous\n\t"							\
	".section\t__ex_table,\"a\"\n\t"				\
	__UA_ADDR "\t1b,4b\n\t"						\
	__UA_ADDR "\t2b,4b\n\t"						\
	".previous"							\
	:"=r" (__pu_err)						\
	:"r" (__pu_val), "o" (__m(__pu_addr)),				\
	 "o" (__m(__pu_addr + 4)), "i" (-EFAULT));			\
})

extern void __put_user_unknown(void);

/*
 * We're generating jump to subroutines which will be outside the range of
 * jump instructions
 */
#ifdef MODULE
#define __MODULE_JAL(destination)					\
	".set\tnoat\n\t"						\
	__UA_LA "\t$1, " #destination "\n\t" 				\
	"jalr\t$1\n\t"							\
	".set\tat\n\t"