xref: /dpdk/lib/eal/include/rte_common.h (revision f665790a5dbad7b645ff46f31d65e977324e7bfc)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 2010-2019 Intel Corporation
3  */
4 
5 #ifndef _RTE_COMMON_H_
6 #define _RTE_COMMON_H_
7 
8 /**
9  * @file
10  *
11  * Generic, commonly-used macro and inline function definitions
12  * for DPDK.
13  */
14 
15 #ifdef __cplusplus
16 extern "C" {
17 #endif
18 
19 #include <assert.h>
20 #include <limits.h>
21 #include <stdint.h>
22 #include <stdalign.h>
23 
24 #include <rte_config.h>
25 
26 /* OS specific include */
27 #include <rte_os.h>
28 
29 #ifndef RTE_TOOLCHAIN_MSVC
30 #ifndef typeof
31 #define typeof __typeof__
32 #endif
33 #endif
34 
35 #ifndef __cplusplus
36 #ifndef asm
37 #define asm __asm__
38 #endif
39 #endif
40 
41 #ifdef RTE_TOOLCHAIN_MSVC
42 #ifdef __cplusplus
43 #define __extension__
44 #endif
45 #endif
46 
47 #ifdef RTE_TOOLCHAIN_MSVC
48 #define __rte_constant(e) 0
49 #else
50 #define __rte_constant(e) __extension__(__builtin_constant_p(e))
51 #endif
52 
53 /*
54  * RTE_TOOLCHAIN_GCC is defined if the target is built with GCC,
55  * while a host application (like pmdinfogen) may have another compiler.
56  * RTE_CC_IS_GNU is true if the file is compiled with GCC,
57  * no matter it is a target or host application.
58  */
59 #define RTE_CC_IS_GNU 0
60 #if defined __clang__
61 #define RTE_CC_CLANG
62 #elif defined __INTEL_COMPILER
63 #define RTE_CC_ICC
64 #elif defined __GNUC__
65 #define RTE_CC_GCC
66 #undef RTE_CC_IS_GNU
67 #define RTE_CC_IS_GNU 1
68 #endif
69 #if RTE_CC_IS_GNU
70 #define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 +	\
71 		__GNUC_PATCHLEVEL__)
72 #endif
73 
74 /**
75  * Force type alignment
76  *
77  * This macro should be used when alignment of a struct or union type
78  * is required. For toolchain compatibility it should appear between
79  * the {struct,union} keyword and tag. e.g.
80  *
81  *   struct __rte_aligned(8) tag { ... };
82  *
83  * If alignment of an object/variable is required then this macro should
84  * not be used, instead prefer C11 alignas(a).
85  */
86 #ifdef RTE_TOOLCHAIN_MSVC
87 #define __rte_aligned(a) __declspec(align(a))
88 #else
89 #define __rte_aligned(a) __attribute__((__aligned__(a)))
90 #endif
91 
92 #ifdef RTE_ARCH_STRICT_ALIGN
93 typedef uint64_t unaligned_uint64_t __rte_aligned(1);
94 typedef uint32_t unaligned_uint32_t __rte_aligned(1);
95 typedef uint16_t unaligned_uint16_t __rte_aligned(1);
96 #else
97 typedef uint64_t unaligned_uint64_t;
98 typedef uint32_t unaligned_uint32_t;
99 typedef uint16_t unaligned_uint16_t;
100 #endif
101 
102 /**
103  * Force a structure to be packed
104  */
105 #ifdef RTE_TOOLCHAIN_MSVC
106 #define __rte_packed
107 #else
108 #define __rte_packed __attribute__((__packed__))
109 #endif
110 
111 /**
112  * Macro to mark a type that is not subject to type-based aliasing rules
113  */
114 #ifdef RTE_TOOLCHAIN_MSVC
115 #define __rte_may_alias
116 #else
117 #define __rte_may_alias __attribute__((__may_alias__))
118 #endif
119 
120 /******* Macro to mark functions and fields scheduled for removal *****/
121 #ifdef RTE_TOOLCHAIN_MSVC
122 #define __rte_deprecated
123 #define __rte_deprecated_msg(msg)
124 #else
125 #define __rte_deprecated	__attribute__((__deprecated__))
126 #define __rte_deprecated_msg(msg)	__attribute__((__deprecated__(msg)))
127 #endif
128 
129 /**
130  *  Macro to mark macros and defines scheduled for removal
131  */
132 #if defined(RTE_CC_GCC) || defined(RTE_CC_CLANG)
133 #define RTE_PRAGMA(x)  _Pragma(#x)
134 #define RTE_PRAGMA_WARNING(w) RTE_PRAGMA(GCC warning #w)
135 #define RTE_DEPRECATED(x)  RTE_PRAGMA_WARNING(#x is deprecated)
136 #else
137 #define RTE_DEPRECATED(x)
138 #endif
139 
140 /**
141  * Mark a function or variable to a weak reference.
142  */
143 #define __rte_weak __attribute__((__weak__))
144 
145 /**
146  * Mark a function to be pure.
147  */
148 #ifdef RTE_TOOLCHAIN_MSVC
149 #define __rte_pure
150 #else
151 #define __rte_pure __attribute__((pure))
152 #endif
153 
154 /**
155  * Force symbol to be generated even if it appears to be unused.
156  */
157 #ifdef RTE_TOOLCHAIN_MSVC
158 #define __rte_used
159 #else
160 #define __rte_used __attribute__((used))
161 #endif
162 
163 /*********** Macros to eliminate unused variable warnings ********/
164 
165 /**
166  * short definition to mark a function parameter unused
167  */
168 #ifdef RTE_TOOLCHAIN_MSVC
169 #define __rte_unused
170 #else
171 #define __rte_unused __attribute__((__unused__))
172 #endif
173 
174 /**
175  * Mark pointer as restricted with regard to pointer aliasing.
176  */
177 #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 199901L
178 #define __rte_restrict __restrict
179 #else
180 #define __rte_restrict restrict
181 #endif
182 
183 /**
184  * definition to mark a variable or function parameter as used so
185  * as to avoid a compiler warning
186  */
187 #define RTE_SET_USED(x) (void)(x)
188 
189 /**
190  * Check format string and its arguments at compile-time.
191  *
192  * GCC on Windows assumes MS-specific format string by default,
193  * even if the underlying stdio implementation is ANSI-compliant,
194  * so this must be overridden.
195  */
196 #ifdef RTE_TOOLCHAIN_MSVC
197 #define __rte_format_printf(format_index, first_arg)
198 #else
199 #if RTE_CC_IS_GNU
200 #define __rte_format_printf(format_index, first_arg) \
201 	__attribute__((format(gnu_printf, format_index, first_arg)))
202 #else
203 #define __rte_format_printf(format_index, first_arg) \
204 	__attribute__((format(printf, format_index, first_arg)))
205 #endif
206 #endif
207 
208 /**
209  * Specify data or function section/segment.
210  */
211 #ifdef RTE_TOOLCHAIN_MSVC
212 #define __rte_section(name) \
213 	__pragma(data_seg(name)) __declspec(allocate(name))
214 #else
215 #define __rte_section(name) \
216 	__attribute__((section(name)))
217 #endif
218 
219 /**
220  * Tells compiler that the function returns a value that points to
221  * memory, where the size is given by the one or two arguments.
222  * Used by compiler to validate object size.
223  */
224 #if defined(RTE_CC_GCC) || defined(RTE_CC_CLANG)
225 #define __rte_alloc_size(...) \
226 	__attribute__((alloc_size(__VA_ARGS__)))
227 #else
228 #define __rte_alloc_size(...)
229 #endif
230 
231 #define RTE_PRIORITY_LOG 101
232 #define RTE_PRIORITY_BUS 110
233 #define RTE_PRIORITY_CLASS 120
234 #define RTE_PRIORITY_LAST 65535
235 
236 #define RTE_PRIO(prio) \
237 	RTE_PRIORITY_ ## prio
238 
239 /**
240  * Run function before main() with high priority.
241  *
242  * @param func
243  *   Constructor function.
244  * @param prio
245  *   Priority number must be above 100.
246  *   Lowest number is the first to run.
247  */
248 #ifndef RTE_INIT_PRIO /* Allow to override from EAL */
249 #ifndef RTE_TOOLCHAIN_MSVC
250 #define RTE_INIT_PRIO(func, prio) \
251 static void __attribute__((constructor(RTE_PRIO(prio)), used)) func(void)
252 #else
253 /* definition from the Microsoft CRT */
254 typedef int(__cdecl *_PIFV)(void);
255 
256 #define CTOR_SECTION_LOG ".CRT$XIB"
257 #define CTOR_SECTION_BUS ".CRT$XIC"
258 #define CTOR_SECTION_CLASS ".CRT$XID"
259 #define CTOR_SECTION_LAST ".CRT$XIY"
260 
261 #define CTOR_PRIORITY_TO_SECTION(priority) CTOR_SECTION_ ## priority
262 
263 #define RTE_INIT_PRIO(name, priority) \
264 	static void name(void); \
265 	static int __cdecl name ## _thunk(void) { name(); return 0; } \
266 	__pragma(const_seg(CTOR_PRIORITY_TO_SECTION(priority))) \
267 	__declspec(allocate(CTOR_PRIORITY_TO_SECTION(priority))) \
268 	    _PIFV name ## _pointer = &name ## _thunk; \
269 	__pragma(const_seg()) \
270 	static void name(void)
271 #endif
272 #endif
273 
274 /**
275  * Run function before main() with low priority.
276  *
277  * The constructor will be run after prioritized constructors.
278  *
279  * @param func
280  *   Constructor function.
281  */
282 #define RTE_INIT(func) \
283 	RTE_INIT_PRIO(func, LAST)
284 
285 /**
286  * Run after main() with low priority.
287  *
288  * @param func
289  *   Destructor function name.
290  * @param prio
291  *   Priority number must be above 100.
292  *   Lowest number is the last to run.
293  */
294 #ifndef RTE_FINI_PRIO /* Allow to override from EAL */
295 #ifndef RTE_TOOLCHAIN_MSVC
296 #define RTE_FINI_PRIO(func, prio) \
297 static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void)
298 #else
299 #define DTOR_SECTION_LOG "mydtor$B"
300 #define DTOR_SECTION_BUS "mydtor$C"
301 #define DTOR_SECTION_CLASS "mydtor$D"
302 #define DTOR_SECTION_LAST "mydtor$Y"
303 
304 #define DTOR_PRIORITY_TO_SECTION(priority) DTOR_SECTION_ ## priority
305 
306 #define RTE_FINI_PRIO(name, priority) \
307 	static void name(void); \
308 	__pragma(const_seg(DTOR_PRIORITY_TO_SECTION(priority))) \
309 	__declspec(allocate(DTOR_PRIORITY_TO_SECTION(priority))) void *name ## _pointer = &name; \
310 	__pragma(const_seg()) \
311 	static void name(void)
312 #endif
313 #endif
314 
315 /**
316  * Run after main() with high priority.
317  *
318  * The destructor will be run *before* prioritized destructors.
319  *
320  * @param func
321  *   Destructor function name.
322  */
323 #define RTE_FINI(func) \
324 	RTE_FINI_PRIO(func, LAST)
325 
326 /**
327  * Hint never returning function
328  */
329 #ifdef RTE_TOOLCHAIN_MSVC
330 #define __rte_noreturn
331 #else
332 #define __rte_noreturn __attribute__((noreturn))
333 #endif
334 
335 /**
336  * Issue a warning in case the function's return value is ignored.
337  *
338  * The use of this attribute should be restricted to cases where
339  * ignoring the marked function's return value is almost always a
340  * bug. With GCC, some effort is required to make clear that ignoring
341  * the return value is intentional. The usual void-casting method to
342  * mark something unused as used does not suppress the warning with
343  * this compiler.
344  *
345  * @code{.c}
346  * __rte_warn_unused_result int foo();
347  *
348  * void ignore_foo_result(void) {
349  *         foo(); // generates a warning with all compilers
350  *
351  *         (void)foo(); // still generates the warning with GCC (but not clang)
352  *
353  *         int unused __rte_unused;
354  *         unused = foo(); // does the trick with all compilers
355  *  }
356  * @endcode
357  */
358 #ifdef RTE_TOOLCHAIN_MSVC
359 #define __rte_warn_unused_result
360 #else
361 #define __rte_warn_unused_result __attribute__((warn_unused_result))
362 #endif
363 
364 /**
365  * Force a function to be inlined
366  */
367 #ifdef RTE_TOOLCHAIN_MSVC
368 #define __rte_always_inline
369 #else
370 #define __rte_always_inline inline __attribute__((always_inline))
371 #endif
372 
373 /**
374  * Force a function to be noinlined
375  */
376 #define __rte_noinline __attribute__((noinline))
377 
378 /**
379  * Hint function in the hot path
380  */
381 #define __rte_hot __attribute__((hot))
382 
383 /**
384  * Hint function in the cold path
385  */
386 #ifdef RTE_TOOLCHAIN_MSVC
387 #define __rte_cold
388 #else
389 #define __rte_cold __attribute__((cold))
390 #endif
391 
392 /**
393  * Disable AddressSanitizer on some code
394  */
395 #ifdef RTE_MALLOC_ASAN
396 #ifdef RTE_CC_CLANG
397 #define __rte_no_asan __attribute__((no_sanitize("address", "hwaddress")))
398 #else
399 #define __rte_no_asan __attribute__((no_sanitize_address))
400 #endif
401 #else /* ! RTE_MALLOC_ASAN */
402 #define __rte_no_asan
403 #endif
404 
405 /*********** Macros for pointer arithmetic ********/
406 
407 /**
408  * add a byte-value offset to a pointer
409  */
410 #define RTE_PTR_ADD(ptr, x) ((void*)((uintptr_t)(ptr) + (x)))
411 
412 /**
413  * subtract a byte-value offset from a pointer
414  */
415 #define RTE_PTR_SUB(ptr, x) ((void *)((uintptr_t)(ptr) - (x)))
416 
417 /**
418  * get the difference between two pointer values, i.e. how far apart
419  * in bytes are the locations they point two. It is assumed that
420  * ptr1 is greater than ptr2.
421  */
422 #define RTE_PTR_DIFF(ptr1, ptr2) ((uintptr_t)(ptr1) - (uintptr_t)(ptr2))
423 
424 /**
425  * Workaround to cast a const field of a structure to non-const type.
426  */
427 #define RTE_CAST_FIELD(var, field, type) \
428 	(*(type *)((uintptr_t)(var) + offsetof(typeof(*(var)), field)))
429 
430 /*********** Macros/static functions for doing alignment ********/
431 
432 
433 /**
434  * Macro to align a pointer to a given power-of-two. The resultant
435  * pointer will be a pointer of the same type as the first parameter, and
436  * point to an address no higher than the first parameter. Second parameter
437  * must be a power-of-two value.
438  */
439 #define RTE_PTR_ALIGN_FLOOR(ptr, align) \
440 	((typeof(ptr))RTE_ALIGN_FLOOR((uintptr_t)(ptr), align))
441 
442 /**
443  * Macro to align a value to a given power-of-two. The resultant value
444  * will be of the same type as the first parameter, and will be no
445  * bigger than the first parameter. Second parameter must be a
446  * power-of-two value.
447  */
448 #define RTE_ALIGN_FLOOR(val, align) \
449 	(typeof(val))((val) & (~((typeof(val))((align) - 1))))
450 
451 /**
452  * Macro to align a pointer to a given power-of-two. The resultant
453  * pointer will be a pointer of the same type as the first parameter, and
454  * point to an address no lower than the first parameter. Second parameter
455  * must be a power-of-two value.
456  */
457 #define RTE_PTR_ALIGN_CEIL(ptr, align) \
458 	RTE_PTR_ALIGN_FLOOR((typeof(ptr))RTE_PTR_ADD(ptr, (align) - 1), align)
459 
460 /**
461  * Macro to align a value to a given power-of-two. The resultant value
462  * will be of the same type as the first parameter, and will be no lower
463  * than the first parameter. Second parameter must be a power-of-two
464  * value.
465  */
466 #define RTE_ALIGN_CEIL(val, align) \
467 	RTE_ALIGN_FLOOR(((val) + ((typeof(val)) (align) - 1)), align)
468 
469 /**
470  * Macro to align a pointer to a given power-of-two. The resultant
471  * pointer will be a pointer of the same type as the first parameter, and
472  * point to an address no lower than the first parameter. Second parameter
473  * must be a power-of-two value.
474  * This function is the same as RTE_PTR_ALIGN_CEIL
475  */
476 #define RTE_PTR_ALIGN(ptr, align) RTE_PTR_ALIGN_CEIL(ptr, align)
477 
478 /**
479  * Macro to align a value to a given power-of-two. The resultant
480  * value will be of the same type as the first parameter, and
481  * will be no lower than the first parameter. Second parameter
482  * must be a power-of-two value.
483  * This function is the same as RTE_ALIGN_CEIL
484  */
485 #define RTE_ALIGN(val, align) RTE_ALIGN_CEIL(val, align)
486 
487 /**
488  * Macro to align a value to the multiple of given value. The resultant
489  * value will be of the same type as the first parameter and will be no lower
490  * than the first parameter.
491  */
492 #define RTE_ALIGN_MUL_CEIL(v, mul) \
493 	((((v) + (typeof(v))(mul) - 1) / ((typeof(v))(mul))) * (typeof(v))(mul))
494 
495 /**
496  * Macro to align a value to the multiple of given value. The resultant
497  * value will be of the same type as the first parameter and will be no higher
498  * than the first parameter.
499  */
500 #define RTE_ALIGN_MUL_FLOOR(v, mul) \
501 	(((v) / ((typeof(v))(mul))) * (typeof(v))(mul))
502 
503 /**
504  * Macro to align value to the nearest multiple of the given value.
505  * The resultant value might be greater than or less than the first parameter
506  * whichever difference is the lowest.
507  */
508 #define RTE_ALIGN_MUL_NEAR(v, mul)				\
509 	__extension__ ({					\
510 		typeof(v) ceil = RTE_ALIGN_MUL_CEIL(v, mul);	\
511 		typeof(v) floor = RTE_ALIGN_MUL_FLOOR(v, mul);	\
512 		(ceil - (v)) > ((v) - floor) ? floor : ceil;	\
513 	})
514 
515 /**
516  * Checks if a pointer is aligned to a given power-of-two value
517  *
518  * @param ptr
519  *   The pointer whose alignment is to be checked
520  * @param align
521  *   The power-of-two value to which the ptr should be aligned
522  *
523  * @return
524  *   True(1) where the pointer is correctly aligned, false(0) otherwise
525  */
526 static inline int
527 rte_is_aligned(const void * const __rte_restrict ptr, const unsigned int align)
528 {
529 	return ((uintptr_t)ptr & (align - 1)) == 0;
530 }
531 
532 /*********** Macros for compile type checks ********/
533 
534 /* Workaround for toolchain issues with missing C11 macro in FreeBSD */
535 #if !defined(static_assert) && !defined(__cplusplus)
536 #define	static_assert	_Static_assert
537 #endif
538 
539 /**
540  * Triggers an error at compilation time if the condition is true.
541  *
542  * The do { } while(0) exists to workaround a bug in clang (#55821)
543  * where it would not handle _Static_assert in a switch case.
544  */
545 #define RTE_BUILD_BUG_ON(condition) do { static_assert(!(condition), #condition); } while (0)
546 
547 /*********** Cache line related macros ********/
548 
549 /** Cache line mask. */
550 #define RTE_CACHE_LINE_MASK (RTE_CACHE_LINE_SIZE-1)
551 
552 /** Return the first cache-aligned value greater or equal to size. */
553 #define RTE_CACHE_LINE_ROUNDUP(size) RTE_ALIGN_CEIL(size, RTE_CACHE_LINE_SIZE)
554 
555 /** Cache line size in terms of log2 */
556 #if RTE_CACHE_LINE_SIZE == 64
557 #define RTE_CACHE_LINE_SIZE_LOG2 6
558 #elif RTE_CACHE_LINE_SIZE == 128
559 #define RTE_CACHE_LINE_SIZE_LOG2 7
560 #else
561 #error "Unsupported cache line size"
562 #endif
563 
564 /** Minimum Cache line size. */
565 #define RTE_CACHE_LINE_MIN_SIZE 64
566 
567 /** Force alignment to cache line. */
568 #define __rte_cache_aligned __rte_aligned(RTE_CACHE_LINE_SIZE)
569 
570 /** Force minimum cache line alignment. */
571 #define __rte_cache_min_aligned __rte_aligned(RTE_CACHE_LINE_MIN_SIZE)
572 
573 #define _RTE_CACHE_GUARD_HELPER2(unique) \
574 	alignas(RTE_CACHE_LINE_SIZE) \
575 	char cache_guard_ ## unique[RTE_CACHE_LINE_SIZE * RTE_CACHE_GUARD_LINES]
576 #define _RTE_CACHE_GUARD_HELPER1(unique) _RTE_CACHE_GUARD_HELPER2(unique)
577 /**
578  * Empty cache lines, to guard against false sharing-like effects
579  * on systems with a next-N-lines hardware prefetcher.
580  *
581  * Use as spacing between data accessed by different lcores,
582  * to prevent cache thrashing on hardware with speculative prefetching.
583  */
584 #define RTE_CACHE_GUARD _RTE_CACHE_GUARD_HELPER1(__COUNTER__)
585 
586 /*********** PA/IOVA type definitions ********/
587 
588 /** Physical address */
589 typedef uint64_t phys_addr_t;
590 #define RTE_BAD_PHYS_ADDR ((phys_addr_t)-1)
591 
592 /**
593  * IO virtual address type.
594  * When the physical addressing mode (IOVA as PA) is in use,
595  * the translation from an IO virtual address (IOVA) to a physical address
596  * is a direct mapping, i.e. the same value.
597  * Otherwise, in virtual mode (IOVA as VA), an IOMMU may do the translation.
598  */
599 typedef uint64_t rte_iova_t;
600 #define RTE_BAD_IOVA ((rte_iova_t)-1)
601 
602 /*********** Structure alignment markers ********/
603 
604 #ifndef RTE_TOOLCHAIN_MSVC
605 
606 /** Generic marker for any place in a structure. */
607 __extension__ typedef void    *RTE_MARKER[0];
608 /** Marker for 1B alignment in a structure. */
609 __extension__ typedef uint8_t  RTE_MARKER8[0];
610 /** Marker for 2B alignment in a structure. */
611 __extension__ typedef uint16_t RTE_MARKER16[0];
612 /** Marker for 4B alignment in a structure. */
613 __extension__ typedef uint32_t RTE_MARKER32[0];
614 /** Marker for 8B alignment in a structure. */
615 __extension__ typedef uint64_t RTE_MARKER64[0];
616 
617 #endif
618 
619 /*********** Macros for calculating min and max **********/
620 
621 /**
622  * Macro to return the minimum of two numbers
623  */
624 #define RTE_MIN(a, b) \
625 	__extension__ ({ \
626 		typeof (a) _a = (a); \
627 		typeof (b) _b = (b); \
628 		_a < _b ? _a : _b; \
629 	})
630 
631 /**
632  * Macro to return the minimum of two numbers
633  *
634  * As opposed to RTE_MIN, it does not use temporary variables so it is not safe
635  * if a or b is an expression. Yet it is guaranteed to be constant for use in
636  * static_assert().
637  */
638 #define RTE_MIN_T(a, b, t) \
639 	((t)(a) < (t)(b) ? (t)(a) : (t)(b))
640 
641 /**
642  * Macro to return the maximum of two numbers
643  */
644 #define RTE_MAX(a, b) \
645 	__extension__ ({ \
646 		typeof (a) _a = (a); \
647 		typeof (b) _b = (b); \
648 		_a > _b ? _a : _b; \
649 	})
650 
651 /**
652  * Macro to return the maximum of two numbers
653  *
654  * As opposed to RTE_MAX, it does not use temporary variables so it is not safe
655  * if a or b is an expression. Yet it is guaranteed to be constant for use in
656  * static_assert().
657  */
658 #define RTE_MAX_T(a, b, t) \
659 	((t)(a) > (t)(b) ? (t)(a) : (t)(b))
660 
661 /*********** Other general functions / macros ********/
662 
663 #ifndef offsetof
664 /** Return the offset of a field in a structure. */
665 #define offsetof(TYPE, MEMBER)  __builtin_offsetof (TYPE, MEMBER)
666 #endif
667 
668 /**
669  * Return pointer to the wrapping struct instance.
670  *
671  * Example:
672  *
673  *  struct wrapper {
674  *      ...
675  *      struct child c;
676  *      ...
677  *  };
678  *
679  *  struct child *x = obtain(...);
680  *  struct wrapper *w = container_of(x, struct wrapper, c);
681  */
682 #ifndef container_of
683 #ifdef RTE_TOOLCHAIN_MSVC
684 #define container_of(ptr, type, member) \
685 			((type *)((uintptr_t)(ptr) - offsetof(type, member)))
686 #else
687 #define container_of(ptr, type, member)	__extension__ ({		\
688 			const typeof(((type *)0)->member) *_ptr = (ptr); \
689 			__rte_unused type *_target_ptr =	\
690 				(type *)(ptr);				\
691 			(type *)(((uintptr_t)_ptr) - offsetof(type, member)); \
692 		})
693 #endif
694 #endif
695 
696 /** Swap two variables. */
697 #define RTE_SWAP(a, b) \
698 	__extension__ ({ \
699 		typeof (a) _a = a; \
700 		a = b; \
701 		b = _a; \
702 	})
703 
704 /**
705  * Get the size of a field in a structure.
706  *
707  * @param type
708  *   The type of the structure.
709  * @param field
710  *   The field in the structure.
711  * @return
712  *   The size of the field in the structure, in bytes.
713  */
714 #define RTE_SIZEOF_FIELD(type, field) (sizeof(((type *)0)->field))
715 
716 #define _RTE_STR(x) #x
717 /** Take a macro value and get a string version of it */
718 #define RTE_STR(x) _RTE_STR(x)
719 
720 /**
721  * ISO C helpers to modify format strings using variadic macros.
722  * This is a replacement for the ", ## __VA_ARGS__" GNU extension.
723  * An empty %s argument is appended to avoid a dangling comma.
724  */
725 #define RTE_FMT(fmt, ...) fmt "%.0s", __VA_ARGS__ ""
726 #define RTE_FMT_HEAD(fmt, ...) fmt
727 #define RTE_FMT_TAIL(fmt, ...) __VA_ARGS__
728 
729 /** Mask value of type "tp" for the first "ln" bit set. */
730 #define	RTE_LEN2MASK(ln, tp)	\
731 	((tp)((uint64_t)-1 >> (sizeof(uint64_t) * CHAR_BIT - (ln))))
732 
733 /** Number of elements in the array. */
734 #define	RTE_DIM(a)	(sizeof (a) / sizeof ((a)[0]))
735 
736 /**
737  * Converts a numeric string to the equivalent uint64_t value.
738  * As well as straight number conversion, also recognises the suffixes
739  * k, m and g for kilobytes, megabytes and gigabytes respectively.
740  *
741  * If a negative number is passed in  i.e. a string with the first non-black
742  * character being "-", zero is returned. Zero is also returned in the case of
743  * an error with the strtoull call in the function.
744  *
745  * @param str
746  *     String containing number to convert.
747  * @return
748  *     Number.
749  */
750 uint64_t
751 rte_str_to_size(const char *str);
752 
753 /**
754  * Function to terminate the application immediately, printing an error
755  * message and returning the exit_code back to the shell.
756  *
757  * This function never returns
758  *
759  * @param exit_code
760  *     The exit code to be returned by the application
761  * @param format
762  *     The format string to be used for printing the message. This can include
763  *     printf format characters which will be expanded using any further parameters
764  *     to the function.
765  */
766 __rte_noreturn void
767 rte_exit(int exit_code, const char *format, ...)
768 	__rte_format_printf(2, 3);
769 
770 #ifdef __cplusplus
771 }
772 #endif
773 
774 #endif
775