linux/drivers/gpu/drm/i915/i915_utils.h
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   1/*
   2 * Copyright © 2016 Intel Corporation
   3 *
   4 * Permission is hereby granted, free of charge, to any person obtaining a
   5 * copy of this software and associated documentation files (the "Software"),
   6 * to deal in the Software without restriction, including without limitation
   7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8 * and/or sell copies of the Software, and to permit persons to whom the
   9 * Software is furnished to do so, subject to the following conditions:
  10 *
  11 * The above copyright notice and this permission notice (including the next
  12 * paragraph) shall be included in all copies or substantial portions of the
  13 * Software.
  14 *
  15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21 * IN THE SOFTWARE.
  22 *
  23 */
  24
  25#ifndef __I915_UTILS_H
  26#define __I915_UTILS_H
  27
  28#include <linux/list.h>
  29#include <linux/overflow.h>
  30#include <linux/sched.h>
  31#include <linux/types.h>
  32#include <linux/workqueue.h>
  33
  34struct drm_i915_private;
  35struct timer_list;
  36
  37#define FDO_BUG_URL "https://gitlab.freedesktop.org/drm/intel/-/wikis/How-to-file-i915-bugs"
  38
  39#undef WARN_ON
  40/* Many gcc seem to no see through this and fall over :( */
  41#if 0
  42#define WARN_ON(x) ({ \
  43        bool __i915_warn_cond = (x); \
  44        if (__builtin_constant_p(__i915_warn_cond)) \
  45                BUILD_BUG_ON(__i915_warn_cond); \
  46        WARN(__i915_warn_cond, "WARN_ON(" #x ")"); })
  47#else
  48#define WARN_ON(x) WARN((x), "%s", "WARN_ON(" __stringify(x) ")")
  49#endif
  50
  51#undef WARN_ON_ONCE
  52#define WARN_ON_ONCE(x) WARN_ONCE((x), "%s", "WARN_ON_ONCE(" __stringify(x) ")")
  53
  54#define MISSING_CASE(x) WARN(1, "Missing case (%s == %ld)\n", \
  55                             __stringify(x), (long)(x))
  56
  57void __printf(3, 4)
  58__i915_printk(struct drm_i915_private *dev_priv, const char *level,
  59              const char *fmt, ...);
  60
  61#define i915_report_error(dev_priv, fmt, ...)                              \
  62        __i915_printk(dev_priv, KERN_ERR, fmt, ##__VA_ARGS__)
  63
  64#if IS_ENABLED(CONFIG_DRM_I915_DEBUG)
  65
  66int __i915_inject_probe_error(struct drm_i915_private *i915, int err,
  67                              const char *func, int line);
  68#define i915_inject_probe_error(_i915, _err) \
  69        __i915_inject_probe_error((_i915), (_err), __func__, __LINE__)
  70bool i915_error_injected(void);
  71
  72#else
  73
  74#define i915_inject_probe_error(i915, e) ({ BUILD_BUG_ON_INVALID(i915); 0; })
  75#define i915_error_injected() false
  76
  77#endif
  78
  79#define i915_inject_probe_failure(i915) i915_inject_probe_error((i915), -ENODEV)
  80
  81#define i915_probe_error(i915, fmt, ...)                                   \
  82        __i915_printk(i915, i915_error_injected() ? KERN_DEBUG : KERN_ERR, \
  83                      fmt, ##__VA_ARGS__)
  84
  85#if defined(GCC_VERSION) && GCC_VERSION >= 70000
  86#define add_overflows_t(T, A, B) \
  87        __builtin_add_overflow_p((A), (B), (T)0)
  88#else
  89#define add_overflows_t(T, A, B) ({ \
  90        typeof(A) a = (A); \
  91        typeof(B) b = (B); \
  92        (T)(a + b) < a; \
  93})
  94#endif
  95
  96#define add_overflows(A, B) \
  97        add_overflows_t(typeof((A) + (B)), (A), (B))
  98
  99#define range_overflows(start, size, max) ({ \
 100        typeof(start) start__ = (start); \
 101        typeof(size) size__ = (size); \
 102        typeof(max) max__ = (max); \
 103        (void)(&start__ == &size__); \
 104        (void)(&start__ == &max__); \
 105        start__ >= max__ || size__ > max__ - start__; \
 106})
 107
 108#define range_overflows_t(type, start, size, max) \
 109        range_overflows((type)(start), (type)(size), (type)(max))
 110
 111#define range_overflows_end(start, size, max) ({ \
 112        typeof(start) start__ = (start); \
 113        typeof(size) size__ = (size); \
 114        typeof(max) max__ = (max); \
 115        (void)(&start__ == &size__); \
 116        (void)(&start__ == &max__); \
 117        start__ > max__ || size__ > max__ - start__; \
 118})
 119
 120#define range_overflows_end_t(type, start, size, max) \
 121        range_overflows_end((type)(start), (type)(size), (type)(max))
 122
 123/* Note we don't consider signbits :| */
 124#define overflows_type(x, T) \
 125        (sizeof(x) > sizeof(T) && (x) >> BITS_PER_TYPE(T))
 126
 127static inline bool
 128__check_struct_size(size_t base, size_t arr, size_t count, size_t *size)
 129{
 130        size_t sz;
 131
 132        if (check_mul_overflow(count, arr, &sz))
 133                return false;
 134
 135        if (check_add_overflow(sz, base, &sz))
 136                return false;
 137
 138        *size = sz;
 139        return true;
 140}
 141
 142/**
 143 * check_struct_size() - Calculate size of structure with trailing array.
 144 * @p: Pointer to the structure.
 145 * @member: Name of the array member.
 146 * @n: Number of elements in the array.
 147 * @sz: Total size of structure and array
 148 *
 149 * Calculates size of memory needed for structure @p followed by an
 150 * array of @n @member elements, like struct_size() but reports
 151 * whether it overflowed, and the resultant size in @sz
 152 *
 153 * Return: false if the calculation overflowed.
 154 */
 155#define check_struct_size(p, member, n, sz) \
 156        likely(__check_struct_size(sizeof(*(p)), \
 157                                   sizeof(*(p)->member) + __must_be_array((p)->member), \
 158                                   n, sz))
 159
 160#define ptr_mask_bits(ptr, n) ({                                        \
 161        unsigned long __v = (unsigned long)(ptr);                       \
 162        (typeof(ptr))(__v & -BIT(n));                                   \
 163})
 164
 165#define ptr_unmask_bits(ptr, n) ((unsigned long)(ptr) & (BIT(n) - 1))
 166
 167#define ptr_unpack_bits(ptr, bits, n) ({                                \
 168        unsigned long __v = (unsigned long)(ptr);                       \
 169        *(bits) = __v & (BIT(n) - 1);                                   \
 170        (typeof(ptr))(__v & -BIT(n));                                   \
 171})
 172
 173#define ptr_pack_bits(ptr, bits, n) ({                                  \
 174        unsigned long __bits = (bits);                                  \
 175        GEM_BUG_ON(__bits & -BIT(n));                                   \
 176        ((typeof(ptr))((unsigned long)(ptr) | __bits));                 \
 177})
 178
 179#define ptr_dec(ptr) ({                                                 \
 180        unsigned long __v = (unsigned long)(ptr);                       \
 181        (typeof(ptr))(__v - 1);                                         \
 182})
 183
 184#define ptr_inc(ptr) ({                                                 \
 185        unsigned long __v = (unsigned long)(ptr);                       \
 186        (typeof(ptr))(__v + 1);                                         \
 187})
 188
 189#define page_mask_bits(ptr) ptr_mask_bits(ptr, PAGE_SHIFT)
 190#define page_unmask_bits(ptr) ptr_unmask_bits(ptr, PAGE_SHIFT)
 191#define page_pack_bits(ptr, bits) ptr_pack_bits(ptr, bits, PAGE_SHIFT)
 192#define page_unpack_bits(ptr, bits) ptr_unpack_bits(ptr, bits, PAGE_SHIFT)
 193
 194#define struct_member(T, member) (((T *)0)->member)
 195
 196#define ptr_offset(ptr, member) offsetof(typeof(*(ptr)), member)
 197
 198#define fetch_and_zero(ptr) ({                                          \
 199        typeof(*ptr) __T = *(ptr);                                      \
 200        *(ptr) = (typeof(*ptr))0;                                       \
 201        __T;                                                            \
 202})
 203
 204static __always_inline ptrdiff_t ptrdiff(const void *a, const void *b)
 205{
 206        return a - b;
 207}
 208
 209/*
 210 * container_of_user: Extract the superclass from a pointer to a member.
 211 *
 212 * Exactly like container_of() with the exception that it plays nicely
 213 * with sparse for __user @ptr.
 214 */
 215#define container_of_user(ptr, type, member) ({                         \
 216        void __user *__mptr = (void __user *)(ptr);                     \
 217        BUILD_BUG_ON_MSG(!__same_type(*(ptr), struct_member(type, member)) && \
 218                         !__same_type(*(ptr), void),                    \
 219                         "pointer type mismatch in container_of()");    \
 220        ((type __user *)(__mptr - offsetof(type, member))); })
 221
 222/*
 223 * check_user_mbz: Check that a user value exists and is zero
 224 *
 225 * Frequently in our uABI we reserve space for future extensions, and
 226 * two ensure that userspace is prepared we enforce that space must
 227 * be zero. (Then any future extension can safely assume a default value
 228 * of 0.)
 229 *
 230 * check_user_mbz() combines checking that the user pointer is accessible
 231 * and that the contained value is zero.
 232 *
 233 * Returns: -EFAULT if not accessible, -EINVAL if !zero, or 0 on success.
 234 */
 235#define check_user_mbz(U) ({                                            \
 236        typeof(*(U)) mbz__;                                             \
 237        get_user(mbz__, (U)) ? -EFAULT : mbz__ ? -EINVAL : 0;           \
 238})
 239
 240static inline u64 ptr_to_u64(const void *ptr)
 241{
 242        return (uintptr_t)ptr;
 243}
 244
 245#define u64_to_ptr(T, x) ({                                             \
 246        typecheck(u64, x);                                              \
 247        (T *)(uintptr_t)(x);                                            \
 248})
 249
 250#define __mask_next_bit(mask) ({                                        \
 251        int __idx = ffs(mask) - 1;                                      \
 252        mask &= ~BIT(__idx);                                            \
 253        __idx;                                                          \
 254})
 255
 256static inline bool is_power_of_2_u64(u64 n)
 257{
 258        return (n != 0 && ((n & (n - 1)) == 0));
 259}
 260
 261static inline void __list_del_many(struct list_head *head,
 262                                   struct list_head *first)
 263{
 264        first->prev = head;
 265        WRITE_ONCE(head->next, first);
 266}
 267
 268static inline int list_is_last_rcu(const struct list_head *list,
 269                                   const struct list_head *head)
 270{
 271        return READ_ONCE(list->next) == head;
 272}
 273
 274static inline unsigned long msecs_to_jiffies_timeout(const unsigned int m)
 275{
 276        unsigned long j = msecs_to_jiffies(m);
 277
 278        return min_t(unsigned long, MAX_JIFFY_OFFSET, j + 1);
 279}
 280
 281/*
 282 * If you need to wait X milliseconds between events A and B, but event B
 283 * doesn't happen exactly after event A, you record the timestamp (jiffies) of
 284 * when event A happened, then just before event B you call this function and
 285 * pass the timestamp as the first argument, and X as the second argument.
 286 */
 287static inline void
 288wait_remaining_ms_from_jiffies(unsigned long timestamp_jiffies, int to_wait_ms)
 289{
 290        unsigned long target_jiffies, tmp_jiffies, remaining_jiffies;
 291
 292        /*
 293         * Don't re-read the value of "jiffies" every time since it may change
 294         * behind our back and break the math.
 295         */
 296        tmp_jiffies = jiffies;
 297        target_jiffies = timestamp_jiffies +
 298                         msecs_to_jiffies_timeout(to_wait_ms);
 299
 300        if (time_after(target_jiffies, tmp_jiffies)) {
 301                remaining_jiffies = target_jiffies - tmp_jiffies;
 302                while (remaining_jiffies)
 303                        remaining_jiffies =
 304                            schedule_timeout_uninterruptible(remaining_jiffies);
 305        }
 306}
 307
 308/**
 309 * __wait_for - magic wait macro
 310 *
 311 * Macro to help avoid open coding check/wait/timeout patterns. Note that it's
 312 * important that we check the condition again after having timed out, since the
 313 * timeout could be due to preemption or similar and we've never had a chance to
 314 * check the condition before the timeout.
 315 */
 316#define __wait_for(OP, COND, US, Wmin, Wmax) ({ \
 317        const ktime_t end__ = ktime_add_ns(ktime_get_raw(), 1000ll * (US)); \
 318        long wait__ = (Wmin); /* recommended min for usleep is 10 us */ \
 319        int ret__;                                                      \
 320        might_sleep();                                                  \
 321        for (;;) {                                                      \
 322                const bool expired__ = ktime_after(ktime_get_raw(), end__); \
 323                OP;                                                     \
 324                /* Guarantee COND check prior to timeout */             \
 325                barrier();                                              \
 326                if (COND) {                                             \
 327                        ret__ = 0;                                      \
 328                        break;                                          \
 329                }                                                       \
 330                if (expired__) {                                        \
 331                        ret__ = -ETIMEDOUT;                             \
 332                        break;                                          \
 333                }                                                       \
 334                usleep_range(wait__, wait__ * 2);                       \
 335                if (wait__ < (Wmax))                                    \
 336                        wait__ <<= 1;                                   \
 337        }                                                               \
 338        ret__;                                                          \
 339})
 340
 341#define _wait_for(COND, US, Wmin, Wmax) __wait_for(, (COND), (US), (Wmin), \
 342                                                   (Wmax))
 343#define wait_for(COND, MS)              _wait_for((COND), (MS) * 1000, 10, 1000)
 344
 345/* If CONFIG_PREEMPT_COUNT is disabled, in_atomic() always reports false. */
 346#if defined(CONFIG_DRM_I915_DEBUG) && defined(CONFIG_PREEMPT_COUNT)
 347# define _WAIT_FOR_ATOMIC_CHECK(ATOMIC) WARN_ON_ONCE((ATOMIC) && !in_atomic())
 348#else
 349# define _WAIT_FOR_ATOMIC_CHECK(ATOMIC) do { } while (0)
 350#endif
 351
 352#define _wait_for_atomic(COND, US, ATOMIC) \
 353({ \
 354        int cpu, ret, timeout = (US) * 1000; \
 355        u64 base; \
 356        _WAIT_FOR_ATOMIC_CHECK(ATOMIC); \
 357        if (!(ATOMIC)) { \
 358                preempt_disable(); \
 359                cpu = smp_processor_id(); \
 360        } \
 361        base = local_clock(); \
 362        for (;;) { \
 363                u64 now = local_clock(); \
 364                if (!(ATOMIC)) \
 365                        preempt_enable(); \
 366                /* Guarantee COND check prior to timeout */ \
 367                barrier(); \
 368                if (COND) { \
 369                        ret = 0; \
 370                        break; \
 371                } \
 372                if (now - base >= timeout) { \
 373                        ret = -ETIMEDOUT; \
 374                        break; \
 375                } \
 376                cpu_relax(); \
 377                if (!(ATOMIC)) { \
 378                        preempt_disable(); \
 379                        if (unlikely(cpu != smp_processor_id())) { \
 380                                timeout -= now - base; \
 381                                cpu = smp_processor_id(); \
 382                                base = local_clock(); \
 383                        } \
 384                } \
 385        } \
 386        ret; \
 387})
 388
 389#define wait_for_us(COND, US) \
 390({ \
 391        int ret__; \
 392        BUILD_BUG_ON(!__builtin_constant_p(US)); \
 393        if ((US) > 10) \
 394                ret__ = _wait_for((COND), (US), 10, 10); \
 395        else \
 396                ret__ = _wait_for_atomic((COND), (US), 0); \
 397        ret__; \
 398})
 399
 400#define wait_for_atomic_us(COND, US) \
 401({ \
 402        BUILD_BUG_ON(!__builtin_constant_p(US)); \
 403        BUILD_BUG_ON((US) > 50000); \
 404        _wait_for_atomic((COND), (US), 1); \
 405})
 406
 407#define wait_for_atomic(COND, MS) wait_for_atomic_us((COND), (MS) * 1000)
 408
 409#define KHz(x) (1000 * (x))
 410#define MHz(x) KHz(1000 * (x))
 411
 412#define KBps(x) (1000 * (x))
 413#define MBps(x) KBps(1000 * (x))
 414#define GBps(x) ((u64)1000 * MBps((x)))
 415
 416static inline const char *yesno(bool v)
 417{
 418        return v ? "yes" : "no";
 419}
 420
 421static inline const char *onoff(bool v)
 422{
 423        return v ? "on" : "off";
 424}
 425
 426static inline const char *enabledisable(bool v)
 427{
 428        return v ? "enable" : "disable";
 429}
 430
 431static inline const char *enableddisabled(bool v)
 432{
 433        return v ? "enabled" : "disabled";
 434}
 435
 436void add_taint_for_CI(struct drm_i915_private *i915, unsigned int taint);
 437static inline void __add_taint_for_CI(unsigned int taint)
 438{
 439        /*
 440         * The system is "ok", just about surviving for the user, but
 441         * CI results are now unreliable as the HW is very suspect.
 442         * CI checks the taint state after every test and will reboot
 443         * the machine if the kernel is tainted.
 444         */
 445        add_taint(taint, LOCKDEP_STILL_OK);
 446}
 447
 448void cancel_timer(struct timer_list *t);
 449void set_timer_ms(struct timer_list *t, unsigned long timeout);
 450
 451static inline bool timer_active(const struct timer_list *t)
 452{
 453        return READ_ONCE(t->expires);
 454}
 455
 456static inline bool timer_expired(const struct timer_list *t)
 457{
 458        return timer_active(t) && !timer_pending(t);
 459}
 460
 461/*
 462 * This is a lookalike for IS_ENABLED() that takes a kconfig value,
 463 * e.g. CONFIG_DRM_I915_SPIN_REQUEST, and evaluates whether it is non-zero
 464 * i.e. whether the configuration is active. Wrapping up the config inside
 465 * a boolean context prevents clang and smatch from complaining about potential
 466 * issues in confusing logical-&& with bitwise-& for constants.
 467 *
 468 * Sadly IS_ENABLED() itself does not work with kconfig values.
 469 *
 470 * Returns 0 if @config is 0, 1 if set to any value.
 471 */
 472#define IS_ACTIVE(config) ((config) != 0)
 473
 474#endif /* !__I915_UTILS_H */
 475