cregit-Linux how code gets into the kernel

Release 4.14 arch/openrisc/include/asm/uaccess.h

/*
 * OpenRISC Linux
 *
 * Linux architectural port borrowing liberally from similar works of
 * others.  All original copyrights apply as per the original source
 * declaration.
 *
 * OpenRISC implementation:
 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
 * et al.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#ifndef __ASM_OPENRISC_UACCESS_H

#define __ASM_OPENRISC_UACCESS_H

/*
 * User space memory access functions
 */
#include <linux/prefetch.h>
#include <linux/string.h>
#include <asm/page.h>
#include <asm/extable.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.
 */

/* addr_limit is the maximum accessible address for the task. we misuse
 * the KERNEL_DS and USER_DS values to both assign and compare the
 * addr_limit values through the equally misnamed get/set_fs macros.
 * (see above)
 */


#define KERNEL_DS	(~0UL)

#define get_ds()	(KERNEL_DS)


#define USER_DS		(TASK_SIZE)

#define get_fs()	(current_thread_info()->addr_limit)

#define set_fs(x)	(current_thread_info()->addr_limit = (x))


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

/* Ensure that the range from addr to addr+size is all within the process'
 * address space
 */

#define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs()-size))

/* Ensure that addr is below task's addr_limit */

#define __addr_ok(addr) ((unsigned long) addr < get_fs())


#define access_ok(type, addr, size) \
	__range_ok((unsigned long)addr, (unsigned long)size)

/*
 * 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.
 *
 * 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).
 *
 * As we use the same address space for kernel and user data on the
 * PowerPC, we can just do these as direct assignments.  (Of course, the
 * exception handling means that it's no longer "just"...)
 */

#define get_user(x, ptr) \
	__get_user_check((x), (ptr), sizeof(*(ptr)))

#define put_user(x, ptr) \
	__put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))


#define __get_user(x, ptr) \
	__get_user_nocheck((x), (ptr), sizeof(*(ptr)))

#define __put_user(x, ptr) \
	__put_user_nocheck((__typeof__(*(ptr)))(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, "l.sb"); break;          \
        case 2: __put_user_asm(x, ptr, retval, "l.sh"); break;          \
        case 4: __put_user_asm(x, ptr, retval, "l.sw"); break;          \
        case 8: __put_user_asm2(x, ptr, retval); break;                 \
        default: __put_user_bad();                                      \
        }                                                               \
} while (0)


struct __large_struct {
	
unsigned long buf[100];
};

#define __m(x) (*(struct __large_struct *)(x))

/*
 * 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.
 */

#define __put_user_asm(x, addr, err, op)			\
	__asm__ __volatile__(                                   \
                "1:     "op" 0(%2),%1\n"                        \
                "2:\n"                                          \
                ".section .fixup,\"ax\"\n"                      \
                "3:     l.addi %0,r0,%3\n"                      \
                "       l.j 2b\n"                               \
                "       l.nop\n"                                \
                ".previous\n"                                   \
                ".section __ex_table,\"a\"\n"                   \
                "       .align 2\n"                             \
                "       .long 1b,3b\n"                          \
                ".previous"                                     \
                : "=r"(err)                                     \
                : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))


#define __put_user_asm2(x, addr, err)				\
	__asm__ __volatile__(                                   \
                "1:     l.sw 0(%2),%1\n"                        \
                "2:     l.sw 4(%2),%H1\n"                       \
                "3:\n"                                          \
                ".section .fixup,\"ax\"\n"                      \
                "4:     l.addi %0,r0,%3\n"                      \
                "       l.j 3b\n"                               \
                "       l.nop\n"                                \
                ".previous\n"                                   \
                ".section __ex_table,\"a\"\n"                   \
                "       .align 2\n"                             \
                "       .long 1b,4b\n"                          \
                "       .long 2b,4b\n"                          \
                ".previous"                                     \
                : "=r"(err)                                     \
                : "r"(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) = (__force __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) = (__force __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, "l.lbz"); break;         \
        case 2: __get_user_asm(x, ptr, retval, "l.lhz"); break;         \
        case 4: __get_user_asm(x, ptr, retval, "l.lwz"); break;         \
        case 8: __get_user_asm2(x, ptr, retval); break;                 \
        default: (x) = __get_user_bad();                                \
        }                                                               \
} while (0)


#define __get_user_asm(x, addr, err, op)		\
	__asm__ __volatile__(                           \
                "1:     "op" %1,0(%2)\n"                \
                "2:\n"                                  \
                ".section .fixup,\"ax\"\n"              \
                "3:     l.addi %0,r0,%3\n"              \
                "       l.addi %1,r0,0\n"               \
                "       l.j 2b\n"                       \
                "       l.nop\n"                        \
                ".previous\n"                           \
                ".section __ex_table,\"a\"\n"           \
                "       .align 2\n"                     \
                "       .long 1b,3b\n"                  \
                ".previous"                             \
                : "=r"(err), "=r"(x)                    \
                : "r"(addr), "i"(-EFAULT), "0"(err))


#define __get_user_asm2(x, addr, err)			\
	__asm__ __volatile__(                           \
                "1:     l.lwz %1,0(%2)\n"               \
                "2:     l.lwz %H1,4(%2)\n"              \
                "3:\n"                                  \
                ".section .fixup,\"ax\"\n"              \
                "4:     l.addi %0,r0,%3\n"              \
                "       l.addi %1,r0,0\n"               \
                "       l.addi %H1,r0,0\n"              \
                "       l.j 3b\n"                       \
                "       l.nop\n"                        \
                ".previous\n"                           \
                ".section __ex_table,\"a\"\n"           \
                "       .align 2\n"                     \
                "       .long 1b,4b\n"                  \
                "       .long 2b,4b\n"                  \
                ".previous"                             \
                : "=r"(err), "=&r"(x)                   \
                : "r"(addr), "i"(-EFAULT), "0"(err))

/* more complex routines */

extern unsigned long __must_check
__copy_tofrom_user(void *to, const void *from, unsigned long size);

static inline unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long size) { return __copy_tofrom_user(to, (__force const void *)from, size); }

Contributors

PersonTokensPropCommitsCommitProp
Jonas Bonn2668.42%133.33%
Al Viro1231.58%266.67%
Total38100.00%3100.00%


static inline unsigned long raw_copy_to_user(void *to, const void __user *from, unsigned long size) { return __copy_tofrom_user((__force void *)to, from, size); }

Contributors

PersonTokensPropCommitsCommitProp
Jonas Bonn2772.97%150.00%
Al Viro1027.03%150.00%
Total37100.00%2100.00%

#define INLINE_COPY_FROM_USER #define INLINE_COPY_TO_USER extern unsigned long __clear_user(void *addr, unsigned long size);
static inline __must_check unsigned long clear_user(void *addr, unsigned long size) { if (likely(access_ok(VERIFY_WRITE, addr, size))) size = __clear_user(addr, size); return size; }

Contributors

PersonTokensPropCommitsCommitProp
Jonas Bonn3990.70%150.00%
Al Viro49.30%150.00%
Total43100.00%2100.00%

#define user_addr_max() \ (uaccess_kernel() ? ~0UL : TASK_SIZE) extern long strncpy_from_user(char *dest, const char __user *src, long count); extern __must_check long strnlen_user(const char __user *str, long n); #endif /* __ASM_OPENRISC_UACCESS_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
Jonas Bonn45392.45%333.33%
Al Viro346.94%444.44%
Michael S. Tsirkin20.41%111.11%
Stafford Horne10.20%111.11%
Total490100.00%9100.00%
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