1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_IA64_UACCESS_H 3 #define _ASM_IA64_UACCESS_H 4 5 /* 6 * This file defines various macros to transfer memory areas across 7 * the user/kernel boundary. This needs to be done carefully because 8 * this code is executed in kernel mode and uses user-specified 9 * addresses. Thus, we need to be careful not to let the user to 10 * trick us into accessing kernel memory that would normally be 11 * inaccessible. This code is also fairly performance sensitive, 12 * so we want to spend as little time doing safety checks as 13 * possible. 14 * 15 * To make matters a bit more interesting, these macros sometimes also 16 * called from within the kernel itself, in which case the address 17 * validity check must be skipped. The get_fs() macro tells us what 18 * to do: if get_fs()==USER_DS, checking is performed, if 19 * get_fs()==KERNEL_DS, checking is bypassed. 20 * 21 * Note that even if the memory area specified by the user is in a 22 * valid address range, it is still possible that we'll get a page 23 * fault while accessing it. This is handled by filling out an 24 * exception handler fixup entry for each instruction that has the 25 * potential to fault. When such a fault occurs, the page fault 26 * handler checks to see whether the faulting instruction has a fixup 27 * associated and, if so, sets r8 to -EFAULT and clears r9 to 0 and 28 * then resumes execution at the continuation point. 29 * 30 * Based on <asm-alpha/uaccess.h>. 31 * 32 * Copyright (C) 1998, 1999, 2001-2004 Hewlett-Packard Co 33 * David Mosberger-Tang <davidm@hpl.hp.com> 34 */ 35 36 #include <linux/compiler.h> 37 #include <linux/page-flags.h> 38 39 #include <asm/intrinsics.h> 40 #include <linux/pgtable.h> 41 #include <asm/io.h> 42 #include <asm/extable.h> 43 44 /* 45 * When accessing user memory, we need to make sure the entire area really is 46 * in user-level space. We also need to make sure that the address doesn't 47 * point inside the virtually mapped linear page table. 48 */ 49 static inline int __access_ok(const void __user *p, unsigned long size) 50 { 51 unsigned long limit = TASK_SIZE; 52 unsigned long addr = (unsigned long)p; 53 54 return likely((size <= limit) && (addr <= (limit - size)) && 55 likely(REGION_OFFSET(addr) < RGN_MAP_LIMIT)); 56 } 57 #define __access_ok __access_ok 58 #include <asm-generic/access_ok.h> 59 60 /* 61 * These are the main single-value transfer routines. They automatically 62 * use the right size if we just have the right pointer type. 63 * 64 * Careful to not 65 * (a) re-use the arguments for side effects (sizeof/typeof is ok) 66 * (b) require any knowledge of processes at this stage 67 */ 68 #define put_user(x, ptr) __put_user_check((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr))) 69 #define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr))) 70 71 /* 72 * The "__xxx" versions do not do address space checking, useful when 73 * doing multiple accesses to the same area (the programmer has to do the 74 * checks by hand with "access_ok()") 75 */ 76 #define __put_user(x, ptr) __put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr))) 77 #define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr))) 78 79 #ifdef ASM_SUPPORTED 80 struct __large_struct { unsigned long buf[100]; }; 81 # define __m(x) (*(struct __large_struct __user *)(x)) 82 83 /* We need to declare the __ex_table section before we can use it in .xdata. */ 84 asm (".section \"__ex_table\", \"a\"\n\t.previous"); 85 86 # define __get_user_size(val, addr, n, err) \ 87 do { \ 88 register long __gu_r8 asm ("r8") = 0; \ 89 register long __gu_r9 asm ("r9"); \ 90 asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n" \ 91 "\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n" \ 92 "[1:]" \ 93 : "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8)); \ 94 (err) = __gu_r8; \ 95 (val) = __gu_r9; \ 96 } while (0) 97 98 /* 99 * The "__put_user_size()" macro tells gcc it reads from memory instead of writing it. This 100 * is because they do not write to any memory gcc knows about, so there are no aliasing 101 * issues. 102 */ 103 # define __put_user_size(val, addr, n, err) \ 104 do { \ 105 register long __pu_r8 asm ("r8") = 0; \ 106 asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n" \ 107 "\t.xdata4 \"__ex_table\", 1b-., 1f-.\n" \ 108 "[1:]" \ 109 : "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), "0"(__pu_r8)); \ 110 (err) = __pu_r8; \ 111 } while (0) 112 113 #else /* !ASM_SUPPORTED */ 114 # define RELOC_TYPE 2 /* ip-rel */ 115 # define __get_user_size(val, addr, n, err) \ 116 do { \ 117 __ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE); \ 118 (err) = ia64_getreg(_IA64_REG_R8); \ 119 (val) = ia64_getreg(_IA64_REG_R9); \ 120 } while (0) 121 # define __put_user_size(val, addr, n, err) \ 122 do { \ 123 __st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE, \ 124 (__force unsigned long) (val)); \ 125 (err) = ia64_getreg(_IA64_REG_R8); \ 126 } while (0) 127 #endif /* !ASM_SUPPORTED */ 128 129 extern void __get_user_unknown (void); 130 131 /* 132 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which 133 * could clobber r8 and r9 (among others). Thus, be careful not to evaluate it while 134 * using r8/r9. 135 */ 136 #define __do_get_user(check, x, ptr, size) \ 137 ({ \ 138 const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \ 139 __typeof__ (size) __gu_size = (size); \ 140 long __gu_err = -EFAULT; \ 141 unsigned long __gu_val = 0; \ 142 if (!check || __access_ok(__gu_ptr, size)) \ 143 switch (__gu_size) { \ 144 case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break; \ 145 case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break; \ 146 case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break; \ 147 case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break; \ 148 default: __get_user_unknown(); break; \ 149 } \ 150 (x) = (__force __typeof__(*(__gu_ptr))) __gu_val; \ 151 __gu_err; \ 152 }) 153 154 #define __get_user_nocheck(x, ptr, size) __do_get_user(0, x, ptr, size) 155 #define __get_user_check(x, ptr, size) __do_get_user(1, x, ptr, size) 156 157 extern void __put_user_unknown (void); 158 159 /* 160 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which 161 * could clobber r8 (among others). Thus, be careful not to evaluate them while using r8. 162 */ 163 #define __do_put_user(check, x, ptr, size) \ 164 ({ \ 165 __typeof__ (x) __pu_x = (x); \ 166 __typeof__ (*(ptr)) __user *__pu_ptr = (ptr); \ 167 __typeof__ (size) __pu_size = (size); \ 168 long __pu_err = -EFAULT; \ 169 \ 170 if (!check || __access_ok(__pu_ptr, __pu_size)) \ 171 switch (__pu_size) { \ 172 case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break; \ 173 case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break; \ 174 case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break; \ 175 case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break; \ 176 default: __put_user_unknown(); break; \ 177 } \ 178 __pu_err; \ 179 }) 180 181 #define __put_user_nocheck(x, ptr, size) __do_put_user(0, x, ptr, size) 182 #define __put_user_check(x, ptr, size) __do_put_user(1, x, ptr, size) 183 184 /* 185 * Complex access routines 186 */ 187 extern unsigned long __must_check __copy_user (void __user *to, const void __user *from, 188 unsigned long count); 189 190 static inline unsigned long 191 raw_copy_to_user(void __user *to, const void *from, unsigned long count) 192 { 193 return __copy_user(to, (__force void __user *) from, count); 194 } 195 196 static inline unsigned long 197 raw_copy_from_user(void *to, const void __user *from, unsigned long count) 198 { 199 return __copy_user((__force void __user *) to, from, count); 200 } 201 202 #define INLINE_COPY_FROM_USER 203 #define INLINE_COPY_TO_USER 204 205 extern unsigned long __do_clear_user (void __user *, unsigned long); 206 207 #define __clear_user(to, n) __do_clear_user(to, n) 208 209 #define clear_user(to, n) \ 210 ({ \ 211 unsigned long __cu_len = (n); \ 212 if (__access_ok(to, __cu_len)) \ 213 __cu_len = __do_clear_user(to, __cu_len); \ 214 __cu_len; \ 215 }) 216 217 218 /* 219 * Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else 220 * strlen. 221 */ 222 extern long __must_check __strncpy_from_user (char *to, const char __user *from, long to_len); 223 224 #define strncpy_from_user(to, from, n) \ 225 ({ \ 226 const char __user * __sfu_from = (from); \ 227 long __sfu_ret = -EFAULT; \ 228 if (__access_ok(__sfu_from, 0)) \ 229 __sfu_ret = __strncpy_from_user((to), __sfu_from, (n)); \ 230 __sfu_ret; \ 231 }) 232 233 /* 234 * Returns: 0 if exception before NUL or reaching the supplied limit 235 * (N), a value greater than N if the limit would be exceeded, else 236 * strlen. 237 */ 238 extern unsigned long __strnlen_user (const char __user *, long); 239 240 #define strnlen_user(str, len) \ 241 ({ \ 242 const char __user *__su_str = (str); \ 243 unsigned long __su_ret = 0; \ 244 if (__access_ok(__su_str, 0)) \ 245 __su_ret = __strnlen_user(__su_str, len); \ 246 __su_ret; \ 247 }) 248 249 #define ARCH_HAS_TRANSLATE_MEM_PTR 1 250 static __inline__ void * 251 xlate_dev_mem_ptr(phys_addr_t p) 252 { 253 struct page *page; 254 void *ptr; 255 256 page = pfn_to_page(p >> PAGE_SHIFT); 257 if (PageUncached(page)) 258 ptr = (void *)p + __IA64_UNCACHED_OFFSET; 259 else 260 ptr = __va(p); 261 262 return ptr; 263 } 264 265 #endif /* _ASM_IA64_UACCESS_H */ 266