LXR linux/arch/powerpc/include/asm/uaccess.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _ARCH_POWERPC_UACCESS_H
   3#define _ARCH_POWERPC_UACCESS_H
   4
   5#include <asm/ppc_asm.h>
   6#include <asm/processor.h>
   7#include <asm/page.h>
   8#include <asm/extable.h>
   9
  10/*
  11 * The fs value determines whether argument validity checking should be
  12 * performed or not.  If get_fs() == USER_DS, checking is performed, with
  13 * get_fs() == KERNEL_DS, checking is bypassed.
  14 *
  15 * For historical reasons, these macros are grossly misnamed.
  16 *
  17 * The fs/ds values are now the highest legal address in the "segment".
  18 * This simplifies the checking in the routines below.
  19 */
  20
  21#define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  22
  23#define KERNEL_DS       MAKE_MM_SEG(~0UL)
  24#ifdef __powerpc64__
  25/* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
  26#define USER_DS         MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
  27#else
  28#define USER_DS         MAKE_MM_SEG(TASK_SIZE - 1)
  29#endif
  30
  31#define get_ds()        (KERNEL_DS)
  32#define get_fs()        (current->thread.addr_limit)
  33
  34static inline void set_fs(mm_segment_t fs)
  35{
  36        current->thread.addr_limit = fs;
  37        /* On user-mode return check addr_limit (fs) is correct */
  38        set_thread_flag(TIF_FSCHECK);
  39}
  40
  41#define segment_eq(a, b)        ((a).seg == (b).seg)
  42
  43#define user_addr_max() (get_fs().seg)
  44
  45#ifdef __powerpc64__
  46/*
  47 * This check is sufficient because there is a large enough
  48 * gap between user addresses and the kernel addresses
  49 */
  50#define __access_ok(addr, size, segment)        \
  51        (((addr) <= (segment).seg) && ((size) <= (segment).seg))
  52
  53#else
  54
  55static inline int __access_ok(unsigned long addr, unsigned long size,
  56                        mm_segment_t seg)
  57{
  58        if (addr > seg.seg)
  59                return 0;
  60        return (size == 0 || size - 1 <= seg.seg - addr);
  61}
  62
  63#endif
  64
  65#define access_ok(type, addr, size)             \
  66        (__chk_user_ptr(addr),                  \
  67         __access_ok((__force unsigned long)(addr), (size), get_fs()))
  68
  69/*
  70 * These are the main single-value transfer routines.  They automatically
  71 * use the right size if we just have the right pointer type.
  72 *
  73 * This gets kind of ugly. We want to return _two_ values in "get_user()"
  74 * and yet we don't want to do any pointers, because that is too much
  75 * of a performance impact. Thus we have a few rather ugly macros here,
  76 * and hide all the ugliness from the user.
  77 *
  78 * The "__xxx" versions of the user access functions are versions that
  79 * do not verify the address space, that must have been done previously
  80 * with a separate "access_ok()" call (this is used when we do multiple
  81 * accesses to the same area of user memory).
  82 *
  83 * As we use the same address space for kernel and user data on the
  84 * PowerPC, we can just do these as direct assignments.  (Of course, the
  85 * exception handling means that it's no longer "just"...)
  86 *
  87 */
  88#define get_user(x, ptr) \
  89        __get_user_check((x), (ptr), sizeof(*(ptr)))
  90#define put_user(x, ptr) \
  91        __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  92
  93#define __get_user(x, ptr) \
  94        __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  95#define __put_user(x, ptr) \
  96        __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  97
  98#define __get_user_inatomic(x, ptr) \
  99        __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
 100#define __put_user_inatomic(x, ptr) \
 101        __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 102
 103extern long __put_user_bad(void);
 104
 105/*
 106 * We don't tell gcc that we are accessing memory, but this is OK
 107 * because we do not write to any memory gcc knows about, so there
 108 * are no aliasing issues.
 109 */
 110#define __put_user_asm(x, addr, err, op)                        \
 111        __asm__ __volatile__(                                   \
 112                "1:     " op " %1,0(%2) # put_user\n"           \
 113                "2:\n"                                          \
 114                ".section .fixup,\"ax\"\n"                      \
 115                "3:     li %0,%3\n"                             \
 116                "       b 2b\n"                                 \
 117                ".previous\n"                                   \
 118                EX_TABLE(1b, 3b)                                \
 119                : "=r" (err)                                    \
 120                : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 121
 122#ifdef __powerpc64__
 123#define __put_user_asm2(x, ptr, retval)                         \
 124          __put_user_asm(x, ptr, retval, "std")
 125#else /* __powerpc64__ */
 126#define __put_user_asm2(x, addr, err)                           \
 127        __asm__ __volatile__(                                   \
 128                "1:     stw %1,0(%2)\n"                         \
 129                "2:     stw %1+1,4(%2)\n"                       \
 130                "3:\n"                                          \
 131                ".section .fixup,\"ax\"\n"                      \
 132                "4:     li %0,%3\n"                             \
 133                "       b 3b\n"                                 \
 134                ".previous\n"                                   \
 135                EX_TABLE(1b, 4b)                                \
 136                EX_TABLE(2b, 4b)                                \
 137                : "=r" (err)                                    \
 138                : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 139#endif /* __powerpc64__ */
 140
 141#define __put_user_size(x, ptr, size, retval)                   \
 142do {                                                            \
 143        retval = 0;                                             \
 144        switch (size) {                                         \
 145          case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
 146          case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
 147          case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
 148          case 8: __put_user_asm2(x, ptr, retval); break;       \
 149          default: __put_user_bad();                            \
 150        }                                                       \
 151} while (0)
 152
 153#define __put_user_nocheck(x, ptr, size)                        \
 154({                                                              \
 155        long __pu_err;                                          \
 156        __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 157        if (!is_kernel_addr((unsigned long)__pu_addr))          \
 158                might_fault();                                  \
 159        __chk_user_ptr(ptr);                                    \
 160        __put_user_size((x), __pu_addr, (size), __pu_err);      \
 161        __pu_err;                                               \
 162})
 163
 164#define __put_user_check(x, ptr, size)                                  \
 165({                                                                      \
 166        long __pu_err = -EFAULT;                                        \
 167        __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 168        might_fault();                                                  \
 169        if (access_ok(VERIFY_WRITE, __pu_addr, size))                   \
 170                __put_user_size((x), __pu_addr, (size), __pu_err);      \
 171        __pu_err;                                                       \
 172})
 173
 174#define __put_user_nosleep(x, ptr, size)                        \
 175({                                                              \
 176        long __pu_err;                                          \
 177        __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 178        __chk_user_ptr(ptr);                                    \
 179        __put_user_size((x), __pu_addr, (size), __pu_err);      \
 180        __pu_err;                                               \
 181})
 182
 183
 184extern long __get_user_bad(void);
 185
 186/*
 187 * This does an atomic 128 byte aligned load from userspace.
 188 * Upto caller to do enable_kernel_vmx() before calling!
 189 */
 190#define __get_user_atomic_128_aligned(kaddr, uaddr, err)                \
 191        __asm__ __volatile__(                           \
 192                "1:     lvx  0,0,%1     # get user\n"   \
 193                "       stvx 0,0,%2     # put kernel\n" \
 194                "2:\n"                                  \
 195                ".section .fixup,\"ax\"\n"              \
 196                "3:     li %0,%3\n"                     \
 197                "       b 2b\n"                         \
 198                ".previous\n"                           \
 199                EX_TABLE(1b, 3b)                        \
 200                : "=r" (err)                    \
 201                : "b" (uaddr), "b" (kaddr), "i" (-EFAULT), "0" (err))
 202
 203#define __get_user_asm(x, addr, err, op)                \
 204        __asm__ __volatile__(                           \
 205                "1:     "op" %1,0(%2)   # get_user\n"   \
 206                "2:\n"                                  \
 207                ".section .fixup,\"ax\"\n"              \
 208                "3:     li %0,%3\n"                     \
 209                "       li %1,0\n"                      \
 210                "       b 2b\n"                         \
 211                ".previous\n"                           \
 212                EX_TABLE(1b, 3b)                        \
 213                : "=r" (err), "=r" (x)                  \
 214                : "b" (addr), "i" (-EFAULT), "0" (err))
 215
 216#ifdef __powerpc64__
 217#define __get_user_asm2(x, addr, err)                   \
 218        __get_user_asm(x, addr, err, "ld")
 219#else /* __powerpc64__ */
 220#define __get_user_asm2(x, addr, err)                   \
 221        __asm__ __volatile__(                           \
 222                "1:     lwz %1,0(%2)\n"                 \
 223                "2:     lwz %1+1,4(%2)\n"               \
 224                "3:\n"                                  \
 225                ".section .fixup,\"ax\"\n"              \
 226                "4:     li %0,%3\n"                     \
 227                "       li %1,0\n"                      \
 228                "       li %1+1,0\n"                    \
 229                "       b 3b\n"                         \
 230                ".previous\n"                           \
 231                EX_TABLE(1b, 4b)                        \
 232                EX_TABLE(2b, 4b)                        \
 233                : "=r" (err), "=&r" (x)                 \
 234                : "b" (addr), "i" (-EFAULT), "0" (err))
 235#endif /* __powerpc64__ */
 236
 237#define __get_user_size(x, ptr, size, retval)                   \
 238do {                                                            \
 239        retval = 0;                                             \
 240        __chk_user_ptr(ptr);                                    \
 241        if (size > sizeof(x))                                   \
 242                (x) = __get_user_bad();                         \
 243        switch (size) {                                         \
 244        case 1: __get_user_asm(x, ptr, retval, "lbz"); break;   \
 245        case 2: __get_user_asm(x, ptr, retval, "lhz"); break;   \
 246        case 4: __get_user_asm(x, ptr, retval, "lwz"); break;   \
 247        case 8: __get_user_asm2(x, ptr, retval);  break;        \
 248        default: (x) = __get_user_bad();                        \
 249        }                                                       \
 250} while (0)
 251
 252/*
 253 * This is a type: either unsigned long, if the argument fits into
 254 * that type, or otherwise unsigned long long.
 255 */
 256#define __long_type(x) \
 257        __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
 258
 259#define __get_user_nocheck(x, ptr, size)                        \
 260({                                                              \
 261        long __gu_err;                                          \
 262        __long_type(*(ptr)) __gu_val;                           \
 263        const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 264        __chk_user_ptr(ptr);                                    \
 265        if (!is_kernel_addr((unsigned long)__gu_addr))          \
 266                might_fault();                                  \
 267        barrier_nospec();                                       \
 268        __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 269        (x) = (__typeof__(*(ptr)))__gu_val;                     \
 270        __gu_err;                                               \
 271})
 272
 273#define __get_user_check(x, ptr, size)                                  \
 274({                                                                      \
 275        long __gu_err = -EFAULT;                                        \
 276        __long_type(*(ptr)) __gu_val = 0;                               \
 277        const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 278        might_fault();                                                  \
 279        if (access_ok(VERIFY_READ, __gu_addr, (size))) {                \
 280                barrier_nospec();                                       \
 281                __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 282        }                                                               \
 283        (x) = (__force __typeof__(*(ptr)))__gu_val;                             \
 284        __gu_err;                                                       \
 285})
 286
 287#define __get_user_nosleep(x, ptr, size)                        \
 288({                                                              \
 289        long __gu_err;                                          \
 290        __long_type(*(ptr)) __gu_val;                           \
 291        const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 292        __chk_user_ptr(ptr);                                    \
 293        barrier_nospec();                                       \
 294        __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 295        (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 296        __gu_err;                                               \
 297})
 298
 299
 300/* more complex routines */
 301
 302extern unsigned long __copy_tofrom_user(void __user *to,
 303                const void __user *from, unsigned long size);
 304
 305#ifdef __powerpc64__
 306static inline unsigned long
 307raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 308{
 309        return __copy_tofrom_user(to, from, n);
 310}
 311#endif /* __powerpc64__ */
 312
 313static inline unsigned long raw_copy_from_user(void *to,
 314                const void __user *from, unsigned long n)
 315{
 316        if (__builtin_constant_p(n) && (n <= 8)) {
 317                unsigned long ret = 1;
 318
 319                switch (n) {
 320                case 1:
 321                        barrier_nospec();
 322                        __get_user_size(*(u8 *)to, from, 1, ret);
 323                        break;
 324                case 2:
 325                        barrier_nospec();
 326                        __get_user_size(*(u16 *)to, from, 2, ret);
 327                        break;
 328                case 4:
 329                        barrier_nospec();
 330                        __get_user_size(*(u32 *)to, from, 4, ret);
 331                        break;
 332                case 8:
 333                        barrier_nospec();
 334                        __get_user_size(*(u64 *)to, from, 8, ret);
 335                        break;
 336                }
 337                if (ret == 0)
 338                        return 0;
 339        }
 340
 341        barrier_nospec();
 342        return __copy_tofrom_user((__force void __user *)to, from, n);
 343}
 344
 345static inline unsigned long raw_copy_to_user(void __user *to,
 346                const void *from, unsigned long n)
 347{
 348        if (__builtin_constant_p(n) && (n <= 8)) {
 349                unsigned long ret = 1;
 350
 351                switch (n) {
 352                case 1:
 353                        __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
 354                        break;
 355                case 2:
 356                        __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
 357                        break;
 358                case 4:
 359                        __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
 360                        break;
 361                case 8:
 362                        __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
 363                        break;
 364                }
 365                if (ret == 0)
 366                        return 0;
 367        }
 368
 369        return __copy_tofrom_user(to, (__force const void __user *)from, n);
 370}
 371
 372extern unsigned long __clear_user(void __user *addr, unsigned long size);
 373
 374static inline unsigned long clear_user(void __user *addr, unsigned long size)
 375{
 376        might_fault();
 377        if (likely(access_ok(VERIFY_WRITE, addr, size)))
 378                return __clear_user(addr, size);
 379        return size;
 380}
 381
 382extern long strncpy_from_user(char *dst, const char __user *src, long count);
 383extern __must_check long strnlen_user(const char __user *str, long n);
 384
 385extern long __copy_from_user_flushcache(void *dst, const void __user *src,
 386                unsigned size);
 387extern void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
 388                           size_t len);
 389
 390#endif  /* _ARCH_POWERPC_UACCESS_H */
 391