cregit-Linux how code gets into the kernel

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

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Authors:    Bjorn Wesen (bjornw@axis.com)
 *             Hans-Peter Nilsson (hp@axis.com)
 */

/* Asm:s have been tweaked (within the domain of correctness) to give
   satisfactory results for "gcc version 2.96 20000427 (experimental)".

   Check regularly...

   Register $r9 is chosen for temporaries, being a call-clobbered register
   first in line to be used (notably for local blocks), not colliding with
   parameter registers.  */

#ifndef _CRIS_UACCESS_H

#define _CRIS_UACCESS_H

#include <asm/processor.h>
#include <asm/page.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.
 */


#define MAKE_MM_SEG(s)	((mm_segment_t) { (s) })

/* 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	MAKE_MM_SEG(0xFFFFFFFF)

#define USER_DS		MAKE_MM_SEG(TASK_SIZE)


#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)


#define __kernel_ok (uaccess_kernel())

#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))

#include <arch/uaccess.h>
#include <asm/extable.h>

/*
 * 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 ugliness 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
 * CRIS, 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_size(x, ptr, size, retval)				\
do {                                                                    \
        retval = 0;                                                     \
        switch (size) {                                                 \
        case 1:                                                         \
                __put_user_asm(x, ptr, retval, "move.b");               \
                break;                                                  \
        case 2:                                                         \
                __put_user_asm(x, ptr, retval, "move.w");               \
                break;                                                  \
        case 4:                                                         \
                __put_user_asm(x, ptr, retval, "move.d");               \
                break;                                                  \
        case 8:                                                         \
                __put_user_asm_64(x, ptr, retval);                      \
                break;                                                  \
        default:                                                        \
                __put_user_bad();                                       \
        }                                                               \
} while (0)


#define __get_user_size(x, ptr, size, retval)				\
do {                                                                    \
        retval = 0;                                                     \
        switch (size) {                                                 \
        case 1:                                                         \
                __get_user_asm(x, ptr, retval, "move.b");               \
                break;                                                  \
        case 2:                                                         \
                __get_user_asm(x, ptr, retval, "move.w");               \
                break;                                                  \
        case 4:                                                         \
                __get_user_asm(x, ptr, retval, "move.d");               \
                break;                                                  \
        case 8:                                                         \
                __get_user_asm_64(x, ptr, retval);                      \
                break;                                                  \
        default:                                                        \
                (x) = __get_user_bad();                                 \
        }                                                               \
} while (0)


#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;                                                       \
})



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

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




#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);

/* More complex functions.  Most are inline, but some call functions that
   live in lib/usercopy.c  */

extern unsigned long __copy_user(void __user *to, const void *from, unsigned long n);
extern unsigned long __copy_user_in(void *to, const void __user *from, unsigned long n);
extern unsigned long __do_clear_user(void __user *to, unsigned long n);


static inline long strncpy_from_user(char *dst, const char __user *src, long count) { long res = -EFAULT; if (access_ok(VERIFY_READ, src, 1)) res = __do_strncpy_from_user(dst, src, count); return res; }

Contributors

PersonTokensPropCommitsCommitProp
Mikael Starvik4690.20%133.33%
Linus Torvalds47.84%133.33%
Adrian Bunk11.96%133.33%
Total51100.00%3100.00%

/* Note that these expand awfully if made into switch constructs, so don't do that. */
static inline unsigned long __constant_copy_from_user(void *to, const void __user *from, unsigned long n) { unsigned long ret = 0; if (n == 0) ; else if (n == 1) __asm_copy_from_user_1(to, from, ret); else if (n == 2) __asm_copy_from_user_2(to, from, ret); else if (n == 3) __asm_copy_from_user_3(to, from, ret); else if (n == 4) __asm_copy_from_user_4(to, from, ret); else if (n == 5) __asm_copy_from_user_5(to, from, ret); else if (n == 6) __asm_copy_from_user_6(to, from, ret); else if (n == 7) __asm_copy_from_user_7(to, from, ret); else if (n == 8) __asm_copy_from_user_8(to, from, ret); else if (n == 9) __asm_copy_from_user_9(to, from, ret); else if (n == 10) __asm_copy_from_user_10(to, from, ret); else if (n == 11) __asm_copy_from_user_11(to, from, ret); else if (n == 12) __asm_copy_from_user_12(to, from, ret); else if (n == 13) __asm_copy_from_user_13(to, from, ret); else if (n == 14) __asm_copy_from_user_14(to, from, ret); else if (n == 15) __asm_copy_from_user_15(to, from, ret); else if (n == 16) __asm_copy_from_user_16(to, from, ret); else if (n == 20) __asm_copy_from_user_20(to, from, ret); else if (n == 24) __asm_copy_from_user_24(to, from, ret); else ret = __copy_user_in(to, from, n); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds33599.11%125.00%
Al Viro10.30%125.00%
Mikael Starvik10.30%125.00%
Adrian Bunk10.30%125.00%
Total338100.00%4100.00%

/* Ditto, don't make a switch out of this. */
static inline unsigned long __constant_copy_to_user(void __user *to, const void *from, unsigned long n) { unsigned long ret = 0; if (n == 0) ; else if (n == 1) __asm_copy_to_user_1(to, from, ret); else if (n == 2) __asm_copy_to_user_2(to, from, ret); else if (n == 3) __asm_copy_to_user_3(to, from, ret); else if (n == 4) __asm_copy_to_user_4(to, from, ret); else if (n == 5) __asm_copy_to_user_5(to, from, ret); else if (n == 6) __asm_copy_to_user_6(to, from, ret); else if (n == 7) __asm_copy_to_user_7(to, from, ret); else if (n == 8) __asm_copy_to_user_8(to, from, ret); else if (n == 9) __asm_copy_to_user_9(to, from, ret); else if (n == 10) __asm_copy_to_user_10(to, from, ret); else if (n == 11) __asm_copy_to_user_11(to, from, ret); else if (n == 12) __asm_copy_to_user_12(to, from, ret); else if (n == 13) __asm_copy_to_user_13(to, from, ret); else if (n == 14) __asm_copy_to_user_14(to, from, ret); else if (n == 15) __asm_copy_to_user_15(to, from, ret); else if (n == 16) __asm_copy_to_user_16(to, from, ret); else if (n == 20) __asm_copy_to_user_20(to, from, ret); else if (n == 24) __asm_copy_to_user_24(to, from, ret); else ret = __copy_user(to, from, n); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds33599.11%125.00%
Adrian Bunk10.30%125.00%
Al Viro10.30%125.00%
Mikael Starvik10.30%125.00%
Total338100.00%4100.00%

/* No switch, please. */
static inline unsigned long __constant_clear_user(void __user *to, unsigned long n) { unsigned long ret = 0; if (n == 0) ; else if (n == 1) __asm_clear_1(to, ret); else if (n == 2) __asm_clear_2(to, ret); else if (n == 3) __asm_clear_3(to, ret); else if (n == 4) __asm_clear_4(to, ret); else if (n == 8) __asm_clear_8(to, ret); else if (n == 12) __asm_clear_12(to, ret); else if (n == 16) __asm_clear_16(to, ret); else if (n == 20) __asm_clear_20(to, ret); else if (n == 24) __asm_clear_24(to, ret); else ret = __do_clear_user(to, n); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds16698.22%125.00%
Al Viro10.59%125.00%
Mikael Starvik10.59%125.00%
Adrian Bunk10.59%125.00%
Total169100.00%4100.00%


static inline size_t clear_user(void __user *to, size_t n) { if (unlikely(!access_ok(VERIFY_WRITE, to, n))) return n; if (__builtin_constant_p(n)) return __constant_clear_user(to, n); else return __do_clear_user(to, n); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro5189.47%150.00%
Linus Torvalds610.53%150.00%
Total57100.00%2100.00%


static inline unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n) { if (__builtin_constant_p(n)) return __constant_copy_from_user(to, from, n); else return __copy_user_in(to, from, n); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro4386.00%375.00%
Linus Torvalds714.00%125.00%
Total50100.00%4100.00%


static inline unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n) { if (__builtin_constant_p(n)) return __constant_copy_to_user(to, from, n); else return __copy_user(to, from, n); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro4386.00%266.67%
Linus Torvalds714.00%133.33%
Total50100.00%3100.00%

#define INLINE_COPY_FROM_USER #define INLINE_COPY_TO_USER
static inline unsigned long __clear_user(void __user *to, unsigned long n) { return __do_clear_user(to, n); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds2288.00%125.00%
Adrian Bunk14.00%125.00%
Jesper Nilsson14.00%125.00%
Al Viro14.00%125.00%
Total25100.00%4100.00%

#endif /* _CRIS_UACCESS_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds114381.99%213.33%
Al Viro15210.90%533.33%
Mikael Starvik705.02%16.67%
Michael S. Tsirkin110.79%16.67%
Jesper Nilsson110.79%320.00%
Adrian Bunk50.36%16.67%
Greg Kroah-Hartman10.07%16.67%
Michael Hayes10.07%16.67%
Total1394100.00%15100.00%
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