cregit-Linux how code gets into the kernel

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

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __METAG_UACCESS_H

#define __METAG_UACCESS_H

/*
 * User space memory access functions
 */

/*
 * 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) })


#define KERNEL_DS       MAKE_MM_SEG(0xFFFFFFFF)

#define USER_DS		MAKE_MM_SEG(PAGE_OFFSET)


#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)


static inline int __access_ok(unsigned long addr, unsigned long size) { /* * Allow access to the user mapped memory area, but not the system area * before it. The check extends to the top of the address space when * kernel access is allowed (there's no real reason to user copy to the * system area in any case). */ if (likely(addr >= META_MEMORY_BASE && addr < get_fs().seg && size <= get_fs().seg - addr)) return true; /* * Explicitly allow NULL pointers here. Parts of the kernel such * as readv/writev use access_ok to validate pointers, but want * to allow NULL pointers for various reasons. NULL pointers are * safe to allow through because the first page is not mappable on * Meta. */ if (!addr) return true; /* Allow access to core code memory area... */ if (addr >= LINCORE_CODE_BASE && addr <= LINCORE_CODE_LIMIT && size <= LINCORE_CODE_LIMIT + 1 - addr) return true; /* ... but no other areas. */ return false; }

Contributors

PersonTokensPropCommitsCommitProp
James Hogan79100.00%2100.00%
Total79100.00%2100.00%

#define access_ok(type, addr, size) __access_ok((unsigned long)(addr), \ (unsigned long)(size)) #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. */ #define put_user(x, ptr) \ __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) #define __put_user(x, ptr) \ __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) extern void __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)) __user *__pu_addr = (ptr); \ if (access_ok(VERIFY_WRITE, __pu_addr, size)) \ __put_user_size((x), __pu_addr, (size), __pu_err); \ __pu_err; \ }) extern long __put_user_asm_b(unsigned int x, void __user *addr); extern long __put_user_asm_w(unsigned int x, void __user *addr); extern long __put_user_asm_d(unsigned int x, void __user *addr); extern long __put_user_asm_l(unsigned long long x, void __user *addr); #define __put_user_size(x, ptr, size, retval) \ do { \ retval = 0; \ switch (size) { \ case 1: \ retval = __put_user_asm_b((__force unsigned int)x, ptr);\ break; \ case 2: \ retval = __put_user_asm_w((__force unsigned int)x, ptr);\ break; \ case 4: \ retval = __put_user_asm_d((__force unsigned int)x, ptr);\ break; \ case 8: \ retval = __put_user_asm_l((__force unsigned long long)x,\ ptr); \ break; \ default: \ __put_user_bad(); \ } \ } while (0) #define get_user(x, ptr) \ __get_user_check((x), (ptr), sizeof(*(ptr))) #define __get_user(x, ptr) \ __get_user_nocheck((x), (ptr), sizeof(*(ptr))) extern long __get_user_bad(void); #define __get_user_nocheck(x, ptr, size) \ ({ \ long __gu_err; \ long long __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; \ long long __gu_val = 0; \ const __typeof__(*(ptr)) __user *__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 unsigned char __get_user_asm_b(const void __user *addr, long *err); extern unsigned short __get_user_asm_w(const void __user *addr, long *err); extern unsigned int __get_user_asm_d(const void __user *addr, long *err); extern unsigned long long __get_user_asm_l(const void __user *addr, long *err); #define __get_user_size(x, ptr, size, retval) \ do { \ retval = 0; \ switch (size) { \ case 1: \ x = __get_user_asm_b(ptr, &retval); break; \ case 2: \ x = __get_user_asm_w(ptr, &retval); break; \ case 4: \ x = __get_user_asm_d(ptr, &retval); break; \ case 8: \ x = __get_user_asm_l(ptr, &retval); break; \ default: \ (x) = __get_user_bad(); \ } \ } while (0) /* * Copy a null terminated string from userspace. * * Must return: * -EFAULT for an exception * count if we hit the buffer limit * bytes copied if we hit a null byte * (without the null byte) */ extern long __must_check __strncpy_from_user(char *dst, const char __user *src, long count);
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); }

Contributors

PersonTokensPropCommitsCommitProp
James Hogan46100.00%2100.00%
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 */ extern long __must_check strnlen_user(const char __user *src, long count); extern unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n); extern unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n); /* * Zero Userspace */ extern unsigned long __must_check __do_clear_user(void __user *to, unsigned long n);
static inline unsigned long clear_user(void __user *to, unsigned long n) { if (access_ok(VERIFY_WRITE, to, n)) return __do_clear_user(to, n); return n; }

Contributors

PersonTokensPropCommitsCommitProp
James Hogan39100.00%1100.00%
Total39100.00%1100.00%

#define __clear_user(to, n) __do_clear_user(to, n) #endif /* _METAG_UACCESS_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
James Hogan58199.15%666.67%
Al Viro30.51%111.11%
Michael S. Tsirkin10.17%111.11%
Greg Kroah-Hartman10.17%111.11%
Total586100.00%9100.00%
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.