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 * For historical reasons, the following macros are grossly misnamed: 46 */ 47 #define KERNEL_DS ((mm_segment_t) { ~0UL }) /* cf. access_ok() */ 48 #define USER_DS ((mm_segment_t) { TASK_SIZE-1 }) /* cf. access_ok() */ 49 50 #define get_fs() (current_thread_info()->addr_limit) 51 #define set_fs(x) (current_thread_info()->addr_limit = (x)) 52 53 #define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) 54 55 /* 56 * When accessing user memory, we need to make sure the entire area really is in 57 * user-level space. In order to do this efficiently, we make sure that the page at 58 * address TASK_SIZE is never valid. We also need to make sure that the address doesn't 59 * point inside the virtually mapped linear page table. 60 */ 61 static inline int __access_ok(const void __user *p, unsigned long size) 62 { 63 unsigned long addr = (unsigned long)p; 64 unsigned long seg = get_fs().seg; 65 return likely(addr <= seg) && 66 (seg == KERNEL_DS.seg || likely(REGION_OFFSET(addr) < RGN_MAP_LIMIT)); 67 } 68 #define access_ok(addr, size) __access_ok((addr), (size)) 69 70 /* 71 * These are the main single-value transfer routines. They automatically 72 * use the right size if we just have the right pointer type. 73 * 74 * Careful to not 75 * (a) re-use the arguments for side effects (sizeof/typeof is ok) 76 * (b) require any knowledge of processes at this stage 77 */ 78 #define put_user(x, ptr) __put_user_check((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr))) 79 #define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr))) 80 81 /* 82 * The "__xxx" versions do not do address space checking, useful when 83 * doing multiple accesses to the same area (the programmer has to do the 84 * checks by hand with "access_ok()") 85 */ 86 #define __put_user(x, ptr) __put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr))) 87 #define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr))) 88 89 #ifdef ASM_SUPPORTED 90 struct __large_struct { unsigned long buf[100]; }; 91 # define __m(x) (*(struct __large_struct __user *)(x)) 92 93 /* We need to declare the __ex_table section before we can use it in .xdata. */ 94 asm (".section \"__ex_table\", \"a\"\n\t.previous"); 95 96 # define __get_user_size(val, addr, n, err) \ 97 do { \ 98 register long __gu_r8 asm ("r8") = 0; \ 99 register long __gu_r9 asm ("r9"); \ 100 asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n" \ 101 "\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n" \ 102 "[1:]" \ 103 : "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8)); \ 104 (err) = __gu_r8; \ 105 (val) = __gu_r9; \ 106 } while (0) 107 108 /* 109 * The "__put_user_size()" macro tells gcc it reads from memory instead of writing it. This 110 * is because they do not write to any memory gcc knows about, so there are no aliasing 111 * issues. 112 */ 113 # define __put_user_size(val, addr, n, err) \ 114 do { \ 115 register long __pu_r8 asm ("r8") = 0; \ 116 asm volatile ("\n[1:]\tst"#n" %1=%r2%P1\t// %0 gets overwritten by exception handler\n" \ 117 "\t.xdata4 \"__ex_table\", 1b-., 1f-.\n" \ 118 "[1:]" \ 119 : "=r"(__pu_r8) : "m"(__m(addr)), "rO"(val), "0"(__pu_r8)); \ 120 (err) = __pu_r8; \ 121 } while (0) 122 123 #else /* !ASM_SUPPORTED */ 124 # define RELOC_TYPE 2 /* ip-rel */ 125 # define __get_user_size(val, addr, n, err) \ 126 do { \ 127 __ld_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE); \ 128 (err) = ia64_getreg(_IA64_REG_R8); \ 129 (val) = ia64_getreg(_IA64_REG_R9); \ 130 } while (0) 131 # define __put_user_size(val, addr, n, err) \ 132 do { \ 133 __st_user("__ex_table", (unsigned long) addr, n, RELOC_TYPE, \ 134 (__force unsigned long) (val)); \ 135 (err) = ia64_getreg(_IA64_REG_R8); \ 136 } while (0) 137 #endif /* !ASM_SUPPORTED */ 138 139 extern void __get_user_unknown (void); 140 141 /* 142 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which 143 * could clobber r8 and r9 (among others). Thus, be careful not to evaluate it while 144 * using r8/r9. 145 */ 146 #define __do_get_user(check, x, ptr, size) \ 147 ({ \ 148 const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \ 149 __typeof__ (size) __gu_size = (size); \ 150 long __gu_err = -EFAULT; \ 151 unsigned long __gu_val = 0; \ 152 if (!check || __access_ok(__gu_ptr, size)) \ 153 switch (__gu_size) { \ 154 case 1: __get_user_size(__gu_val, __gu_ptr, 1, __gu_err); break; \ 155 case 2: __get_user_size(__gu_val, __gu_ptr, 2, __gu_err); break; \ 156 case 4: __get_user_size(__gu_val, __gu_ptr, 4, __gu_err); break; \ 157 case 8: __get_user_size(__gu_val, __gu_ptr, 8, __gu_err); break; \ 158 default: __get_user_unknown(); break; \ 159 } \ 160 (x) = (__force __typeof__(*(__gu_ptr))) __gu_val; \ 161 __gu_err; \ 162 }) 163 164 #define __get_user_nocheck(x, ptr, size) __do_get_user(0, x, ptr, size) 165 #define __get_user_check(x, ptr, size) __do_get_user(1, x, ptr, size) 166 167 extern void __put_user_unknown (void); 168 169 /* 170 * Evaluating arguments X, PTR, SIZE, and SEGMENT may involve subroutine-calls, which 171 * could clobber r8 (among others). Thus, be careful not to evaluate them while using r8. 172 */ 173 #define __do_put_user(check, x, ptr, size) \ 174 ({ \ 175 __typeof__ (x) __pu_x = (x); \ 176 __typeof__ (*(ptr)) __user *__pu_ptr = (ptr); \ 177 __typeof__ (size) __pu_size = (size); \ 178 long __pu_err = -EFAULT; \ 179 \ 180 if (!check || __access_ok(__pu_ptr, __pu_size)) \ 181 switch (__pu_size) { \ 182 case 1: __put_user_size(__pu_x, __pu_ptr, 1, __pu_err); break; \ 183 case 2: __put_user_size(__pu_x, __pu_ptr, 2, __pu_err); break; \ 184 case 4: __put_user_size(__pu_x, __pu_ptr, 4, __pu_err); break; \ 185 case 8: __put_user_size(__pu_x, __pu_ptr, 8, __pu_err); break; \ 186 default: __put_user_unknown(); break; \ 187 } \ 188 __pu_err; \ 189 }) 190 191 #define __put_user_nocheck(x, ptr, size) __do_put_user(0, x, ptr, size) 192 #define __put_user_check(x, ptr, size) __do_put_user(1, x, ptr, size) 193 194 /* 195 * Complex access routines 196 */ 197 extern unsigned long __must_check __copy_user (void __user *to, const void __user *from, 198 unsigned long count); 199 200 static inline unsigned long 201 raw_copy_to_user(void __user *to, const void *from, unsigned long count) 202 { 203 return __copy_user(to, (__force void __user *) from, count); 204 } 205 206 static inline unsigned long 207 raw_copy_from_user(void *to, const void __user *from, unsigned long count) 208 { 209 return __copy_user((__force void __user *) to, from, count); 210 } 211 212 #define INLINE_COPY_FROM_USER 213 #define INLINE_COPY_TO_USER 214 215 extern unsigned long __do_clear_user (void __user *, unsigned long); 216 217 #define __clear_user(to, n) __do_clear_user(to, n) 218 219 #define clear_user(to, n) \ 220 ({ \ 221 unsigned long __cu_len = (n); \ 222 if (__access_ok(to, __cu_len)) \ 223 __cu_len = __do_clear_user(to, __cu_len); \ 224 __cu_len; \ 225 }) 226 227 228 /* 229 * Returns: -EFAULT if exception before terminator, N if the entire buffer filled, else 230 * strlen. 231 */ 232 extern long __must_check __strncpy_from_user (char *to, const char __user *from, long to_len); 233 234 #define strncpy_from_user(to, from, n) \ 235 ({ \ 236 const char __user * __sfu_from = (from); \ 237 long __sfu_ret = -EFAULT; \ 238 if (__access_ok(__sfu_from, 0)) \ 239 __sfu_ret = __strncpy_from_user((to), __sfu_from, (n)); \ 240 __sfu_ret; \ 241 }) 242 243 /* 244 * Returns: 0 if exception before NUL or reaching the supplied limit 245 * (N), a value greater than N if the limit would be exceeded, else 246 * strlen. 247 */ 248 extern unsigned long __strnlen_user (const char __user *, long); 249 250 #define strnlen_user(str, len) \ 251 ({ \ 252 const char __user *__su_str = (str); \ 253 unsigned long __su_ret = 0; \ 254 if (__access_ok(__su_str, 0)) \ 255 __su_ret = __strnlen_user(__su_str, len); \ 256 __su_ret; \ 257 }) 258 259 #define ARCH_HAS_TRANSLATE_MEM_PTR 1 260 static __inline__ void * 261 xlate_dev_mem_ptr(phys_addr_t p) 262 { 263 struct page *page; 264 void *ptr; 265 266 page = pfn_to_page(p >> PAGE_SHIFT); 267 if (PageUncached(page)) 268 ptr = (void *)p + __IA64_UNCACHED_OFFSET; 269 else 270 ptr = __va(p); 271 272 return ptr; 273 } 274 275 /* 276 * Convert a virtual cached kernel memory pointer to an uncached pointer 277 */ 278 static __inline__ void * 279 xlate_dev_kmem_ptr(void *p) 280 { 281 struct page *page; 282 void *ptr; 283 284 page = virt_to_page((unsigned long)p); 285 if (PageUncached(page)) 286 ptr = (void *)__pa(p) + __IA64_UNCACHED_OFFSET; 287 else 288 ptr = p; 289 290 return ptr; 291 } 292 293 #endif /* _ASM_IA64_UACCESS_H */ 294