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