cregit-Linux how code gets into the kernel

Release 4.12 include/asm-generic/uaccess.h

#ifndef __ASM_GENERIC_UACCESS_H

#define __ASM_GENERIC_UACCESS_H

/*
 * User space memory access functions, these should work
 * on any machine that has kernel and user data in the same
 * address space, e.g. all NOMMU machines.
 */
#include <linux/string.h>

#include <asm/segment.h>


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

#ifndef KERNEL_DS

#define KERNEL_DS	MAKE_MM_SEG(~0UL)
#endif

#ifndef USER_DS

#define USER_DS		MAKE_MM_SEG(TASK_SIZE - 1)
#endif

#ifndef get_fs

#define get_ds()	(KERNEL_DS)

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


static inline void set_fs(mm_segment_t fs) { current_thread_info()->addr_limit = fs; }

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Arnd Bergmann17100.00%1100.00%
Total17100.00%1100.00%

#endif #ifndef segment_eq #define segment_eq(a, b) ((a).seg == (b).seg) #endif #define access_ok(type, addr, size) __access_ok((unsigned long)(addr),(size)) /* * The architecture should really override this if possible, at least * doing a check on the get_fs() */ #ifndef __access_ok
static inline int __access_ok(unsigned long addr, unsigned long size) { return 1; }

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Arnd Bergmann18100.00%1100.00%
Total18100.00%1100.00%

#endif /* * These are the main single-value transfer routines. They automatically * use the right size if we just have the right pointer type. * This version just falls back to copy_{from,to}_user, which should * provide a fast-path for small values. */ #define __put_user(x, ptr) \ ({ \ __typeof__(*(ptr)) __x = (x); \ int __pu_err = -EFAULT; \ __chk_user_ptr(ptr); \ switch (sizeof (*(ptr))) { \ case 1: \ case 2: \ case 4: \ case 8: \ __pu_err = __put_user_fn(sizeof (*(ptr)), \ ptr, &__x); \ break; \ default: \ __put_user_bad(); \ break; \ } \ __pu_err; \ }) #define put_user(x, ptr) \ ({ \ void *__p = (ptr); \ might_fault(); \ access_ok(VERIFY_WRITE, __p, sizeof(*ptr)) ? \ __put_user((x), ((__typeof__(*(ptr)) *)__p)) : \ -EFAULT; \ }) #ifndef __put_user_fn
static inline int __put_user_fn(size_t size, void __user *ptr, void *x) { return unlikely(raw_copy_to_user(ptr, x, size)) ? -EFAULT : 0; }

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PersonTokensPropCommitsCommitProp
Arnd Bergmann1951.35%150.00%
Al Viro1848.65%150.00%
Total37100.00%2100.00%

#define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k) #endif extern int __put_user_bad(void) __attribute__((noreturn)); #define __get_user(x, ptr) \ ({ \ int __gu_err = -EFAULT; \ __chk_user_ptr(ptr); \ switch (sizeof(*(ptr))) { \ case 1: { \ unsigned char __x = 0; \ __gu_err = __get_user_fn(sizeof (*(ptr)), \ ptr, &__x); \ (x) = *(__force __typeof__(*(ptr)) *) &__x; \ break; \ }; \ case 2: { \ unsigned short __x = 0; \ __gu_err = __get_user_fn(sizeof (*(ptr)), \ ptr, &__x); \ (x) = *(__force __typeof__(*(ptr)) *) &__x; \ break; \ }; \ case 4: { \ unsigned int __x = 0; \ __gu_err = __get_user_fn(sizeof (*(ptr)), \ ptr, &__x); \ (x) = *(__force __typeof__(*(ptr)) *) &__x; \ break; \ }; \ case 8: { \ unsigned long long __x = 0; \ __gu_err = __get_user_fn(sizeof (*(ptr)), \ ptr, &__x); \ (x) = *(__force __typeof__(*(ptr)) *) &__x; \ break; \ }; \ default: \ __get_user_bad(); \ break; \ } \ __gu_err; \ }) #define get_user(x, ptr) \ ({ \ const void *__p = (ptr); \ might_fault(); \ access_ok(VERIFY_READ, __p, sizeof(*ptr)) ? \ __get_user((x), (__typeof__(*(ptr)) *)__p) : \ ((x) = (__typeof__(*(ptr)))0,-EFAULT); \ }) #ifndef __get_user_fn
static inline int __get_user_fn(size_t size, const void __user *ptr, void *x) { return unlikely(raw_copy_from_user(x, ptr, size)) ? -EFAULT : 0; }

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PersonTokensPropCommitsCommitProp
Arnd Bergmann2052.63%150.00%
Al Viro1847.37%150.00%
Total38100.00%2100.00%

#define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k) #endif extern int __get_user_bad(void) __attribute__((noreturn)); /* * Copy a null terminated string from userspace. */ #ifndef __strncpy_from_user
static inline long __strncpy_from_user(char *dst, const char __user *src, long count) { char *tmp; strncpy(dst, (const char __force *)src, count); for (tmp = dst; *tmp && count > 0; tmp++, count--) ; return (tmp - dst); }

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PersonTokensPropCommitsCommitProp
Arnd Bergmann66100.00%1100.00%
Total66100.00%1100.00%

#endif
static inline long strncpy_from_user(char *dst, const char __user *src, long count) { if (!access_ok(VERIFY_READ, src, 1)) return -EFAULT; return __strncpy_from_user(dst, src, count); }

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Arnd Bergmann4393.48%150.00%
Mike Frysinger36.52%150.00%
Total46100.00%2100.00%

/* * Return the size of a string (including the ending 0) * * Return 0 on exception, a value greater than N if too long */ #ifndef __strnlen_user #define __strnlen_user(s, n) (strnlen((s), (n)) + 1) #endif /* * Unlike strnlen, strnlen_user includes the nul terminator in * its returned count. Callers should check for a returned value * greater than N as an indication the string is too long. */
static inline long strnlen_user(const char __user *src, long n) { if (!access_ok(VERIFY_READ, src, 1)) return 0; return __strnlen_user(src, n); }

Contributors

PersonTokensPropCommitsCommitProp
Arnd Bergmann2153.85%133.33%
Mike Frysinger1538.46%133.33%
Guan Xuetao37.69%133.33%
Total39100.00%3100.00%


static inline long strlen_user(const char __user *src) { return strnlen_user(src, 32767); }

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Arnd Bergmann21100.00%1100.00%
Total21100.00%1100.00%

/* * Zero Userspace */ #ifndef __clear_user
static inline __must_check unsigned long __clear_user(void __user *to, unsigned long n) { memset((void __force *)to, 0, n); return 0; }

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Arnd Bergmann35100.00%1100.00%
Total35100.00%1100.00%

#endif
static inline __must_check unsigned long clear_user(void __user *to, unsigned long n) { might_fault(); if (!access_ok(VERIFY_WRITE, to, n)) return n; return __clear_user(to, n); }

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PersonTokensPropCommitsCommitProp
Arnd Bergmann4090.91%133.33%
Mike Frysinger36.82%133.33%
Michael S. Tsirkin12.27%133.33%
Total44100.00%3100.00%

#include <asm/extable.h> #endif /* __ASM_GENERIC_UACCESS_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
Arnd Bergmann45679.44%17.14%
Al Viro417.14%428.57%
Vineet Gupta376.45%214.29%
Mike Frysinger213.66%214.29%
Guan Xuetao91.57%17.14%
Mark Salter71.22%17.14%
Michael S. Tsirkin10.17%17.14%
Geert Uytterhoeven10.17%17.14%
Yoshinori Sato10.17%17.14%
Total574100.00%14100.00%
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