/* * User space memory access functions for Nios II * * Copyright (C) 2010-2011, Tobias Klauser * Copyright (C) 2009, Wind River Systems Inc * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com * * 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. */ #ifndef _ASM_NIOS2_UACCESS_H #define _ASM_NIOS2_UACCESS_H #include #include #include #include #define VERIFY_READ 0 #define VERIFY_WRITE 1 /* * The exception table consists of pairs of addresses: the first is the * address of an instruction that is allowed to fault, and the second is * the address at which the program should continue. No registers are * modified, so it is entirely up to the continuation code to figure out * what to do. * * All the routines below use bits of fixup code that are out of line * with the main instruction path. This means when everything is well, * we don't even have to jump over them. Further, they do not intrude * on our cache or tlb entries. */ struct exception_table_entry { unsigned long insn; unsigned long fixup; }; extern int fixup_exception(struct pt_regs *regs); /* * Segment stuff */ #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) #define USER_DS MAKE_MM_SEG(0x80000000UL) #define KERNEL_DS MAKE_MM_SEG(0) #define get_ds() (KERNEL_DS) #define get_fs() (current_thread_info()->addr_limit) #define set_fs(seg) (current_thread_info()->addr_limit = (seg)) #define segment_eq(a, b) ((a).seg == (b).seg) #define __access_ok(addr, len) \ (((signed long)(((long)get_fs().seg) & \ ((long)(addr) | (((long)(addr)) + (len)) | (len)))) == 0) #define access_ok(type, addr, len) \ likely(__access_ok((unsigned long)(addr), (unsigned long)(len))) # define __EX_TABLE_SECTION ".section __ex_table,\"a\"\n" /* * Zero Userspace */ static inline unsigned long __must_check __clear_user(void __user *to, unsigned long n) { __asm__ __volatile__ ( "1: stb zero, 0(%1)\n" " addi %0, %0, -1\n" " addi %1, %1, 1\n" " bne %0, zero, 1b\n" "2:\n" __EX_TABLE_SECTION ".word 1b, 2b\n" ".previous\n" : "=r" (n), "=r" (to) : "0" (n), "1" (to) ); return n; } static inline unsigned long __must_check clear_user(void __user *to, unsigned long n) { if (!access_ok(VERIFY_WRITE, to, n)) return n; return __clear_user(to, n); } extern long __copy_from_user(void *to, const void __user *from, unsigned long n); extern long __copy_to_user(void __user *to, const void *from, unsigned long n); static inline long copy_from_user(void *to, const void __user *from, unsigned long n) { if (!access_ok(VERIFY_READ, from, n)) return n; return __copy_from_user(to, from, n); } static inline long copy_to_user(void __user *to, const void *from, unsigned long n) { if (!access_ok(VERIFY_WRITE, to, n)) return n; return __copy_to_user(to, from, n); } extern long strncpy_from_user(char *__to, const char __user *__from, long __len); extern long strnlen_user(const char __user *s, long n); #define __copy_from_user_inatomic __copy_from_user #define __copy_to_user_inatomic __copy_to_user /* Optimized macros */ #define __get_user_asm(val, insn, addr, err) \ { \ __asm__ __volatile__( \ " movi %0, %3\n" \ "1: " insn " %1, 0(%2)\n" \ " movi %0, 0\n" \ "2:\n" \ " .section __ex_table,\"a\"\n" \ " .word 1b, 2b\n" \ " .previous" \ : "=&r" (err), "=r" (val) \ : "r" (addr), "i" (-EFAULT)); \ } #define __get_user_unknown(val, size, ptr, err) do { \ err = 0; \ if (copy_from_user(&(val), ptr, size)) { \ err = -EFAULT; \ } \ } while (0) #define __get_user_common(val, size, ptr, err) \ do { \ switch (size) { \ case 1: \ __get_user_asm(val, "ldbu", ptr, err); \ break; \ case 2: \ __get_user_asm(val, "ldhu", ptr, err); \ break; \ case 4: \ __get_user_asm(val, "ldw", ptr, err); \ break; \ default: \ __get_user_unknown(val, size, ptr, err); \ break; \ } \ } while (0) #define __get_user(x, ptr) \ ({ \ long __gu_err = -EFAULT; \ const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \ unsigned long __gu_val; \ __get_user_common(__gu_val, sizeof(*(ptr)), __gu_ptr, __gu_err);\ (x) = (__force __typeof__(x))__gu_val; \ __gu_err; \ }) #define get_user(x, ptr) \ ({ \ long __gu_err = -EFAULT; \ const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \ unsigned long __gu_val = 0; \ if (access_ok(VERIFY_READ, __gu_ptr, sizeof(*__gu_ptr))) \ __get_user_common(__gu_val, sizeof(*__gu_ptr), \ __gu_ptr, __gu_err); \ (x) = (__force __typeof__(x))__gu_val; \ __gu_err; \ }) #define __put_user_asm(val, insn, ptr, err) \ { \ __asm__ __volatile__( \ " movi %0, %3\n" \ "1: " insn " %1, 0(%2)\n" \ " movi %0, 0\n" \ "2:\n" \ " .section __ex_table,\"a\"\n" \ " .word 1b, 2b\n" \ " .previous\n" \ : "=&r" (err) \ : "r" (val), "r" (ptr), "i" (-EFAULT)); \ } #define put_user(x, ptr) \ ({ \ long __pu_err = -EFAULT; \ __typeof__(*(ptr)) __user *__pu_ptr = (ptr); \ __typeof__(*(ptr)) __pu_val = (__typeof(*ptr))(x); \ if (access_ok(VERIFY_WRITE, __pu_ptr, sizeof(*__pu_ptr))) { \ switch (sizeof(*__pu_ptr)) { \ case 1: \ __put_user_asm(__pu_val, "stb", __pu_ptr, __pu_err); \ break; \ case 2: \ __put_user_asm(__pu_val, "sth", __pu_ptr, __pu_err); \ break; \ case 4: \ __put_user_asm(__pu_val, "stw", __pu_ptr, __pu_err); \ break; \ default: \ /* XXX: This looks wrong... */ \ __pu_err = 0; \ if (copy_to_user(__pu_ptr, &(__pu_val), \ sizeof(*__pu_ptr))) \ __pu_err = -EFAULT; \ break; \ } \ } \ __pu_err; \ }) #define __put_user(x, ptr) put_user(x, ptr) #endif /* _ASM_NIOS2_UACCESS_H */