xref: /dpdk/lib/eal/include/rte_common.h (revision 515cd4a488b6a0c6e40d20e6b10d8e89657dc23f)
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 <stdint.h>
20 #include <limits.h>
21 
22 #include <rte_config.h>
23 
24 /* OS specific include */
25 #include <rte_os.h>
26 
27 #ifndef typeof
28 #define typeof __typeof__
29 #endif
30 
31 #ifndef __cplusplus
32 #ifndef asm
33 #define asm __asm__
34 #endif
35 #endif
36 
37 /** C extension macro for environments lacking C11 features. */
38 #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 201112L
39 #define RTE_STD_C11 __extension__
40 #else
41 #define RTE_STD_C11
42 #endif
43 
44 /*
45  * RTE_TOOLCHAIN_GCC is defined if the target is built with GCC,
46  * while a host application (like pmdinfogen) may have another compiler.
47  * RTE_CC_IS_GNU is true if the file is compiled with GCC,
48  * no matter it is a target or host application.
49  */
50 #define RTE_CC_IS_GNU 0
51 #if defined __clang__
52 #define RTE_CC_CLANG
53 #elif defined __INTEL_COMPILER
54 #define RTE_CC_ICC
55 #elif defined __GNUC__
56 #define RTE_CC_GCC
57 #undef RTE_CC_IS_GNU
58 #define RTE_CC_IS_GNU 1
59 #endif
60 #if RTE_CC_IS_GNU
61 #define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 +	\
62 		__GNUC_PATCHLEVEL__)
63 #endif
64 
65 /**
66  * Force alignment
67  */
68 #define __rte_aligned(a) __attribute__((__aligned__(a)))
69 
70 #ifdef RTE_ARCH_STRICT_ALIGN
71 typedef uint64_t unaligned_uint64_t __rte_aligned(1);
72 typedef uint32_t unaligned_uint32_t __rte_aligned(1);
73 typedef uint16_t unaligned_uint16_t __rte_aligned(1);
74 #else
75 typedef uint64_t unaligned_uint64_t;
76 typedef uint32_t unaligned_uint32_t;
77 typedef uint16_t unaligned_uint16_t;
78 #endif
79 
80 /**
81  * Force a structure to be packed
82  */
83 #define __rte_packed __attribute__((__packed__))
84 
85 /**
86  * Macro to mark a type that is not subject to type-based aliasing rules
87  */
88 #define __rte_may_alias __attribute__((__may_alias__))
89 
90 /******* Macro to mark functions and fields scheduled for removal *****/
91 #define __rte_deprecated	__attribute__((__deprecated__))
92 #define __rte_deprecated_msg(msg)	__attribute__((__deprecated__(msg)))
93 
94 /**
95  *  Macro to mark macros and defines scheduled for removal
96  */
97 #if defined(RTE_CC_GCC) || defined(RTE_CC_CLANG)
98 #define RTE_PRAGMA(x)  _Pragma(#x)
99 #define RTE_PRAGMA_WARNING(w) RTE_PRAGMA(GCC warning #w)
100 #define RTE_DEPRECATED(x)  RTE_PRAGMA_WARNING(#x is deprecated)
101 #else
102 #define RTE_DEPRECATED(x)
103 #endif
104 
105 /**
106  * Mark a function or variable to a weak reference.
107  */
108 #define __rte_weak __attribute__((__weak__))
109 
110 /**
111  * Force symbol to be generated even if it appears to be unused.
112  */
113 #define __rte_used __attribute__((used))
114 
115 /*********** Macros to eliminate unused variable warnings ********/
116 
117 /**
118  * short definition to mark a function parameter unused
119  */
120 #define __rte_unused __attribute__((__unused__))
121 
122 /**
123  * Mark pointer as restricted with regard to pointer aliasing.
124  */
125 #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 199901L
126 #define __rte_restrict __restrict
127 #else
128 #define __rte_restrict restrict
129 #endif
130 
131 /**
132  * definition to mark a variable or function parameter as used so
133  * as to avoid a compiler warning
134  */
135 #define RTE_SET_USED(x) (void)(x)
136 
137 /**
138  * Check format string and its arguments at compile-time.
139  *
140  * GCC on Windows assumes MS-specific format string by default,
141  * even if the underlying stdio implementation is ANSI-compliant,
142  * so this must be overridden.
143  */
144 #if RTE_CC_IS_GNU
145 #define __rte_format_printf(format_index, first_arg) \
146 	__attribute__((format(gnu_printf, format_index, first_arg)))
147 #else
148 #define __rte_format_printf(format_index, first_arg) \
149 	__attribute__((format(printf, format_index, first_arg)))
150 #endif
151 
152 /**
153  * Tells compiler that the function returns a value that points to
154  * memory, where the size is given by the one or two arguments.
155  * Used by compiler to validate object size.
156  */
157 #if defined(RTE_CC_GCC) || defined(RTE_CC_CLANG)
158 #define __rte_alloc_size(...) \
159 	__attribute__((alloc_size(__VA_ARGS__)))
160 #else
161 #define __rte_alloc_size(...)
162 #endif
163 
164 #define RTE_PRIORITY_LOG 101
165 #define RTE_PRIORITY_BUS 110
166 #define RTE_PRIORITY_CLASS 120
167 #define RTE_PRIORITY_LAST 65535
168 
169 #define RTE_PRIO(prio) \
170 	RTE_PRIORITY_ ## prio
171 
172 /**
173  * Run function before main() with high priority.
174  *
175  * @param func
176  *   Constructor function.
177  * @param prio
178  *   Priority number must be above 100.
179  *   Lowest number is the first to run.
180  */
181 #ifndef RTE_INIT_PRIO /* Allow to override from EAL */
182 #define RTE_INIT_PRIO(func, prio) \
183 static void __attribute__((constructor(RTE_PRIO(prio)), used)) func(void)
184 #endif
185 
186 /**
187  * Run function before main() with low priority.
188  *
189  * The constructor will be run after prioritized constructors.
190  *
191  * @param func
192  *   Constructor function.
193  */
194 #define RTE_INIT(func) \
195 	RTE_INIT_PRIO(func, LAST)
196 
197 /**
198  * Run after main() with low priority.
199  *
200  * @param func
201  *   Destructor function name.
202  * @param prio
203  *   Priority number must be above 100.
204  *   Lowest number is the last to run.
205  */
206 #ifndef RTE_FINI_PRIO /* Allow to override from EAL */
207 #define RTE_FINI_PRIO(func, prio) \
208 static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void)
209 #endif
210 
211 /**
212  * Run after main() with high priority.
213  *
214  * The destructor will be run *before* prioritized destructors.
215  *
216  * @param func
217  *   Destructor function name.
218  */
219 #define RTE_FINI(func) \
220 	RTE_FINI_PRIO(func, LAST)
221 
222 /**
223  * Hint never returning function
224  */
225 #define __rte_noreturn __attribute__((noreturn))
226 
227 /**
228  * Issue a warning in case the function's return value is ignored.
229  *
230  * The use of this attribute should be restricted to cases where
231  * ignoring the marked function's return value is almost always a
232  * bug. With GCC, some effort is required to make clear that ignoring
233  * the return value is intentional. The usual void-casting method to
234  * mark something unused as used does not suppress the warning with
235  * this compiler.
236  *
237  * @code{.c}
238  * __rte_warn_unused_result int foo();
239  *
240  * void ignore_foo_result(void) {
241  *         foo(); // generates a warning with all compilers
242  *
243  *         (void)foo(); // still generates the warning with GCC (but not clang)
244  *
245  *         int unused __rte_unused;
246  *         unused = foo(); // does the trick with all compilers
247  *  }
248  * @endcode
249  */
250 #define __rte_warn_unused_result __attribute__((warn_unused_result))
251 
252 /**
253  * Force a function to be inlined
254  */
255 #define __rte_always_inline inline __attribute__((always_inline))
256 
257 /**
258  * Force a function to be noinlined
259  */
260 #define __rte_noinline __attribute__((noinline))
261 
262 /**
263  * Hint function in the hot path
264  */
265 #define __rte_hot __attribute__((hot))
266 
267 /**
268  * Hint function in the cold path
269  */
270 #define __rte_cold __attribute__((cold))
271 
272 /**
273  * Disable AddressSanitizer on some code
274  */
275 #ifdef RTE_MALLOC_ASAN
276 #ifdef RTE_CC_CLANG
277 #define __rte_no_asan __attribute__((no_sanitize("address", "hwaddress")))
278 #else
279 #define __rte_no_asan __attribute__((no_sanitize_address))
280 #endif
281 #else /* ! RTE_MALLOC_ASAN */
282 #define __rte_no_asan
283 #endif
284 
285 /*********** Macros for pointer arithmetic ********/
286 
287 /**
288  * add a byte-value offset to a pointer
289  */
290 #define RTE_PTR_ADD(ptr, x) ((void*)((uintptr_t)(ptr) + (x)))
291 
292 /**
293  * subtract a byte-value offset from a pointer
294  */
295 #define RTE_PTR_SUB(ptr, x) ((void *)((uintptr_t)(ptr) - (x)))
296 
297 /**
298  * get the difference between two pointer values, i.e. how far apart
299  * in bytes are the locations they point two. It is assumed that
300  * ptr1 is greater than ptr2.
301  */
302 #define RTE_PTR_DIFF(ptr1, ptr2) ((uintptr_t)(ptr1) - (uintptr_t)(ptr2))
303 
304 /**
305  * Workaround to cast a const field of a structure to non-const type.
306  */
307 #define RTE_CAST_FIELD(var, field, type) \
308 	(*(type *)((uintptr_t)(var) + offsetof(typeof(*(var)), field)))
309 
310 /*********** Macros/static functions for doing alignment ********/
311 
312 
313 /**
314  * Macro to align a pointer to a given power-of-two. The resultant
315  * pointer will be a pointer of the same type as the first parameter, and
316  * point to an address no higher than the first parameter. Second parameter
317  * must be a power-of-two value.
318  */
319 #define RTE_PTR_ALIGN_FLOOR(ptr, align) \
320 	((typeof(ptr))RTE_ALIGN_FLOOR((uintptr_t)(ptr), align))
321 
322 /**
323  * Macro to align a value to a given power-of-two. The resultant value
324  * will be of the same type as the first parameter, and will be no
325  * bigger than the first parameter. Second parameter must be a
326  * power-of-two value.
327  */
328 #define RTE_ALIGN_FLOOR(val, align) \
329 	(typeof(val))((val) & (~((typeof(val))((align) - 1))))
330 
331 /**
332  * Macro to align a pointer to a given power-of-two. The resultant
333  * pointer will be a pointer of the same type as the first parameter, and
334  * point to an address no lower than the first parameter. Second parameter
335  * must be a power-of-two value.
336  */
337 #define RTE_PTR_ALIGN_CEIL(ptr, align) \
338 	RTE_PTR_ALIGN_FLOOR((typeof(ptr))RTE_PTR_ADD(ptr, (align) - 1), align)
339 
340 /**
341  * Macro to align a value to a given power-of-two. The resultant value
342  * will be of the same type as the first parameter, and will be no lower
343  * than the first parameter. Second parameter must be a power-of-two
344  * value.
345  */
346 #define RTE_ALIGN_CEIL(val, align) \
347 	RTE_ALIGN_FLOOR(((val) + ((typeof(val)) (align) - 1)), align)
348 
349 /**
350  * Macro to align a pointer to a given power-of-two. The resultant
351  * pointer will be a pointer of the same type as the first parameter, and
352  * point to an address no lower than the first parameter. Second parameter
353  * must be a power-of-two value.
354  * This function is the same as RTE_PTR_ALIGN_CEIL
355  */
356 #define RTE_PTR_ALIGN(ptr, align) RTE_PTR_ALIGN_CEIL(ptr, align)
357 
358 /**
359  * Macro to align a value to a given power-of-two. The resultant
360  * value will be of the same type as the first parameter, and
361  * will be no lower than the first parameter. Second parameter
362  * must be a power-of-two value.
363  * This function is the same as RTE_ALIGN_CEIL
364  */
365 #define RTE_ALIGN(val, align) RTE_ALIGN_CEIL(val, align)
366 
367 /**
368  * Macro to align a value to the multiple of given value. The resultant
369  * value will be of the same type as the first parameter and will be no lower
370  * than the first parameter.
371  */
372 #define RTE_ALIGN_MUL_CEIL(v, mul) \
373 	((((v) + (typeof(v))(mul) - 1) / ((typeof(v))(mul))) * (typeof(v))(mul))
374 
375 /**
376  * Macro to align a value to the multiple of given value. The resultant
377  * value will be of the same type as the first parameter and will be no higher
378  * than the first parameter.
379  */
380 #define RTE_ALIGN_MUL_FLOOR(v, mul) \
381 	(((v) / ((typeof(v))(mul))) * (typeof(v))(mul))
382 
383 /**
384  * Macro to align value to the nearest multiple of the given value.
385  * The resultant value might be greater than or less than the first parameter
386  * whichever difference is the lowest.
387  */
388 #define RTE_ALIGN_MUL_NEAR(v, mul)				\
389 	({							\
390 		typeof(v) ceil = RTE_ALIGN_MUL_CEIL(v, mul);	\
391 		typeof(v) floor = RTE_ALIGN_MUL_FLOOR(v, mul);	\
392 		(ceil - (v)) > ((v) - floor) ? floor : ceil;	\
393 	})
394 
395 /**
396  * Checks if a pointer is aligned to a given power-of-two value
397  *
398  * @param ptr
399  *   The pointer whose alignment is to be checked
400  * @param align
401  *   The power-of-two value to which the ptr should be aligned
402  *
403  * @return
404  *   True(1) where the pointer is correctly aligned, false(0) otherwise
405  */
406 static inline int
407 rte_is_aligned(const void * const __rte_restrict ptr, const unsigned int align)
408 {
409 	return ((uintptr_t)ptr & (align - 1)) == 0;
410 }
411 
412 /*********** Macros for compile type checks ********/
413 
414 /**
415  * Triggers an error at compilation time if the condition is true.
416  */
417 #define RTE_BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
418 
419 /*********** Cache line related macros ********/
420 
421 /** Cache line mask. */
422 #define RTE_CACHE_LINE_MASK (RTE_CACHE_LINE_SIZE-1)
423 
424 /** Return the first cache-aligned value greater or equal to size. */
425 #define RTE_CACHE_LINE_ROUNDUP(size) RTE_ALIGN_CEIL(size, RTE_CACHE_LINE_SIZE)
426 
427 /** Cache line size in terms of log2 */
428 #if RTE_CACHE_LINE_SIZE == 64
429 #define RTE_CACHE_LINE_SIZE_LOG2 6
430 #elif RTE_CACHE_LINE_SIZE == 128
431 #define RTE_CACHE_LINE_SIZE_LOG2 7
432 #else
433 #error "Unsupported cache line size"
434 #endif
435 
436 /** Minimum Cache line size. */
437 #define RTE_CACHE_LINE_MIN_SIZE 64
438 
439 /** Force alignment to cache line. */
440 #define __rte_cache_aligned __rte_aligned(RTE_CACHE_LINE_SIZE)
441 
442 /** Force minimum cache line alignment. */
443 #define __rte_cache_min_aligned __rte_aligned(RTE_CACHE_LINE_MIN_SIZE)
444 
445 /*********** PA/IOVA type definitions ********/
446 
447 /** Physical address */
448 typedef uint64_t phys_addr_t;
449 #define RTE_BAD_PHYS_ADDR ((phys_addr_t)-1)
450 
451 /**
452  * IO virtual address type.
453  * When the physical addressing mode (IOVA as PA) is in use,
454  * the translation from an IO virtual address (IOVA) to a physical address
455  * is a direct mapping, i.e. the same value.
456  * Otherwise, in virtual mode (IOVA as VA), an IOMMU may do the translation.
457  */
458 typedef uint64_t rte_iova_t;
459 #define RTE_BAD_IOVA ((rte_iova_t)-1)
460 
461 /*********** Structure alignment markers ********/
462 
463 /** Generic marker for any place in a structure. */
464 __extension__ typedef void    *RTE_MARKER[0];
465 /** Marker for 1B alignment in a structure. */
466 __extension__ typedef uint8_t  RTE_MARKER8[0];
467 /** Marker for 2B alignment in a structure. */
468 __extension__ typedef uint16_t RTE_MARKER16[0];
469 /** Marker for 4B alignment in a structure. */
470 __extension__ typedef uint32_t RTE_MARKER32[0];
471 /** Marker for 8B alignment in a structure. */
472 __extension__ typedef uint64_t RTE_MARKER64[0];
473 
474 /**
475  * Combines 32b inputs most significant set bits into the least
476  * significant bits to construct a value with the same MSBs as x
477  * but all 1's under it.
478  *
479  * @param x
480  *    The integer whose MSBs need to be combined with its LSBs
481  * @return
482  *    The combined value.
483  */
484 static inline uint32_t
485 rte_combine32ms1b(uint32_t x)
486 {
487 	x |= x >> 1;
488 	x |= x >> 2;
489 	x |= x >> 4;
490 	x |= x >> 8;
491 	x |= x >> 16;
492 
493 	return x;
494 }
495 
496 /**
497  * Combines 64b inputs most significant set bits into the least
498  * significant bits to construct a value with the same MSBs as x
499  * but all 1's under it.
500  *
501  * @param v
502  *    The integer whose MSBs need to be combined with its LSBs
503  * @return
504  *    The combined value.
505  */
506 static inline uint64_t
507 rte_combine64ms1b(uint64_t v)
508 {
509 	v |= v >> 1;
510 	v |= v >> 2;
511 	v |= v >> 4;
512 	v |= v >> 8;
513 	v |= v >> 16;
514 	v |= v >> 32;
515 
516 	return v;
517 }
518 
519 /*********** Macros to work with powers of 2 ********/
520 
521 /**
522  * Macro to return 1 if n is a power of 2, 0 otherwise
523  */
524 #define RTE_IS_POWER_OF_2(n) ((n) && !(((n) - 1) & (n)))
525 
526 /**
527  * Returns true if n is a power of 2
528  * @param n
529  *     Number to check
530  * @return 1 if true, 0 otherwise
531  */
532 static inline int
533 rte_is_power_of_2(uint32_t n)
534 {
535 	return n && !(n & (n - 1));
536 }
537 
538 /**
539  * Aligns input parameter to the next power of 2
540  *
541  * @param x
542  *   The integer value to align
543  *
544  * @return
545  *   Input parameter aligned to the next power of 2
546  */
547 static inline uint32_t
548 rte_align32pow2(uint32_t x)
549 {
550 	x--;
551 	x = rte_combine32ms1b(x);
552 
553 	return x + 1;
554 }
555 
556 /**
557  * Aligns input parameter to the previous power of 2
558  *
559  * @param x
560  *   The integer value to align
561  *
562  * @return
563  *   Input parameter aligned to the previous power of 2
564  */
565 static inline uint32_t
566 rte_align32prevpow2(uint32_t x)
567 {
568 	x = rte_combine32ms1b(x);
569 
570 	return x - (x >> 1);
571 }
572 
573 /**
574  * Aligns 64b input parameter to the next power of 2
575  *
576  * @param v
577  *   The 64b value to align
578  *
579  * @return
580  *   Input parameter aligned to the next power of 2
581  */
582 static inline uint64_t
583 rte_align64pow2(uint64_t v)
584 {
585 	v--;
586 	v = rte_combine64ms1b(v);
587 
588 	return v + 1;
589 }
590 
591 /**
592  * Aligns 64b input parameter to the previous power of 2
593  *
594  * @param v
595  *   The 64b value to align
596  *
597  * @return
598  *   Input parameter aligned to the previous power of 2
599  */
600 static inline uint64_t
601 rte_align64prevpow2(uint64_t v)
602 {
603 	v = rte_combine64ms1b(v);
604 
605 	return v - (v >> 1);
606 }
607 
608 /*********** Macros for calculating min and max **********/
609 
610 /**
611  * Macro to return the minimum of two numbers
612  */
613 #define RTE_MIN(a, b) \
614 	__extension__ ({ \
615 		typeof (a) _a = (a); \
616 		typeof (b) _b = (b); \
617 		_a < _b ? _a : _b; \
618 	})
619 
620 /**
621  * Macro to return the maximum of two numbers
622  */
623 #define RTE_MAX(a, b) \
624 	__extension__ ({ \
625 		typeof (a) _a = (a); \
626 		typeof (b) _b = (b); \
627 		_a > _b ? _a : _b; \
628 	})
629 
630 /*********** Other general functions / macros ********/
631 
632 /**
633  * Searches the input parameter for the least significant set bit
634  * (starting from zero).
635  * If a least significant 1 bit is found, its bit index is returned.
636  * If the content of the input parameter is zero, then the content of the return
637  * value is undefined.
638  * @param v
639  *     input parameter, should not be zero.
640  * @return
641  *     least significant set bit in the input parameter.
642  */
643 static inline uint32_t
644 rte_bsf32(uint32_t v)
645 {
646 	return (uint32_t)__builtin_ctz(v);
647 }
648 
649 /**
650  * Searches the input parameter for the least significant set bit
651  * (starting from zero). Safe version (checks for input parameter being zero).
652  *
653  * @warning ``pos`` must be a valid pointer. It is not checked!
654  *
655  * @param v
656  *     The input parameter.
657  * @param pos
658  *     If ``v`` was not 0, this value will contain position of least significant
659  *     bit within the input parameter.
660  * @return
661  *     Returns 0 if ``v`` was 0, otherwise returns 1.
662  */
663 static inline int
664 rte_bsf32_safe(uint32_t v, uint32_t *pos)
665 {
666 	if (v == 0)
667 		return 0;
668 
669 	*pos = rte_bsf32(v);
670 	return 1;
671 }
672 
673 /**
674  * Return the rounded-up log2 of a integer.
675  *
676  * @note Contrary to the logarithm mathematical operation,
677  * rte_log2_u32(0) == 0 and not -inf.
678  *
679  * @param v
680  *     The input parameter.
681  * @return
682  *     The rounded-up log2 of the input, or 0 if the input is 0.
683  */
684 static inline uint32_t
685 rte_log2_u32(uint32_t v)
686 {
687 	if (v == 0)
688 		return 0;
689 	v = rte_align32pow2(v);
690 	return rte_bsf32(v);
691 }
692 
693 
694 /**
695  * Return the last (most-significant) bit set.
696  *
697  * @note The last (most significant) bit is at position 32.
698  * @note rte_fls_u32(0) = 0, rte_fls_u32(1) = 1, rte_fls_u32(0x80000000) = 32
699  *
700  * @param x
701  *     The input parameter.
702  * @return
703  *     The last (most-significant) bit set, or 0 if the input is 0.
704  */
705 static inline int
706 rte_fls_u32(uint32_t x)
707 {
708 	return (x == 0) ? 0 : 32 - __builtin_clz(x);
709 }
710 
711 /**
712  * Searches the input parameter for the least significant set bit
713  * (starting from zero).
714  * If a least significant 1 bit is found, its bit index is returned.
715  * If the content of the input parameter is zero, then the content of the return
716  * value is undefined.
717  * @param v
718  *     input parameter, should not be zero.
719  * @return
720  *     least significant set bit in the input parameter.
721  */
722 static inline int
723 rte_bsf64(uint64_t v)
724 {
725 	return (uint32_t)__builtin_ctzll(v);
726 }
727 
728 /**
729  * Searches the input parameter for the least significant set bit
730  * (starting from zero). Safe version (checks for input parameter being zero).
731  *
732  * @warning ``pos`` must be a valid pointer. It is not checked!
733  *
734  * @param v
735  *     The input parameter.
736  * @param pos
737  *     If ``v`` was not 0, this value will contain position of least significant
738  *     bit within the input parameter.
739  * @return
740  *     Returns 0 if ``v`` was 0, otherwise returns 1.
741  */
742 static inline int
743 rte_bsf64_safe(uint64_t v, uint32_t *pos)
744 {
745 	if (v == 0)
746 		return 0;
747 
748 	*pos = rte_bsf64(v);
749 	return 1;
750 }
751 
752 /**
753  * Return the last (most-significant) bit set.
754  *
755  * @note The last (most significant) bit is at position 64.
756  * @note rte_fls_u64(0) = 0, rte_fls_u64(1) = 1,
757  *       rte_fls_u64(0x8000000000000000) = 64
758  *
759  * @param x
760  *     The input parameter.
761  * @return
762  *     The last (most-significant) bit set, or 0 if the input is 0.
763  */
764 static inline int
765 rte_fls_u64(uint64_t x)
766 {
767 	return (x == 0) ? 0 : 64 - __builtin_clzll(x);
768 }
769 
770 /**
771  * Return the rounded-up log2 of a 64-bit integer.
772  *
773  * @note Contrary to the logarithm mathematical operation,
774  * rte_log2_u64(0) == 0 and not -inf.
775  *
776  * @param v
777  *     The input parameter.
778  * @return
779  *     The rounded-up log2 of the input, or 0 if the input is 0.
780  */
781 static inline uint32_t
782 rte_log2_u64(uint64_t v)
783 {
784 	if (v == 0)
785 		return 0;
786 	v = rte_align64pow2(v);
787 	/* we checked for v being 0 already, so no undefined behavior */
788 	return rte_bsf64(v);
789 }
790 
791 #ifndef offsetof
792 /** Return the offset of a field in a structure. */
793 #define offsetof(TYPE, MEMBER)  __builtin_offsetof (TYPE, MEMBER)
794 #endif
795 
796 /**
797  * Return pointer to the wrapping struct instance.
798  *
799  * Example:
800  *
801  *  struct wrapper {
802  *      ...
803  *      struct child c;
804  *      ...
805  *  };
806  *
807  *  struct child *x = obtain(...);
808  *  struct wrapper *w = container_of(x, struct wrapper, c);
809  */
810 #ifndef container_of
811 #define container_of(ptr, type, member)	__extension__ ({		\
812 			const typeof(((type *)0)->member) *_ptr = (ptr); \
813 			__rte_unused type *_target_ptr =	\
814 				(type *)(ptr);				\
815 			(type *)(((uintptr_t)_ptr) - offsetof(type, member)); \
816 		})
817 #endif
818 
819 /** Swap two variables. */
820 #define RTE_SWAP(a, b) \
821 	__extension__ ({ \
822 		typeof (a) _a = a; \
823 		a = b; \
824 		b = _a; \
825 	})
826 
827 /**
828  * Get the size of a field in a structure.
829  *
830  * @param type
831  *   The type of the structure.
832  * @param field
833  *   The field in the structure.
834  * @return
835  *   The size of the field in the structure, in bytes.
836  */
837 #define RTE_SIZEOF_FIELD(type, field) (sizeof(((type *)0)->field))
838 
839 #define _RTE_STR(x) #x
840 /** Take a macro value and get a string version of it */
841 #define RTE_STR(x) _RTE_STR(x)
842 
843 /**
844  * ISO C helpers to modify format strings using variadic macros.
845  * This is a replacement for the ", ## __VA_ARGS__" GNU extension.
846  * An empty %s argument is appended to avoid a dangling comma.
847  */
848 #define RTE_FMT(fmt, ...) fmt "%.0s", __VA_ARGS__ ""
849 #define RTE_FMT_HEAD(fmt, ...) fmt
850 #define RTE_FMT_TAIL(fmt, ...) __VA_ARGS__
851 
852 /** Mask value of type "tp" for the first "ln" bit set. */
853 #define	RTE_LEN2MASK(ln, tp)	\
854 	((tp)((uint64_t)-1 >> (sizeof(uint64_t) * CHAR_BIT - (ln))))
855 
856 /** Number of elements in the array. */
857 #define	RTE_DIM(a)	(sizeof (a) / sizeof ((a)[0]))
858 
859 /**
860  * Converts a numeric string to the equivalent uint64_t value.
861  * As well as straight number conversion, also recognises the suffixes
862  * k, m and g for kilobytes, megabytes and gigabytes respectively.
863  *
864  * If a negative number is passed in  i.e. a string with the first non-black
865  * character being "-", zero is returned. Zero is also returned in the case of
866  * an error with the strtoull call in the function.
867  *
868  * @param str
869  *     String containing number to convert.
870  * @return
871  *     Number.
872  */
873 uint64_t
874 rte_str_to_size(const char *str);
875 
876 /**
877  * Function to terminate the application immediately, printing an error
878  * message and returning the exit_code back to the shell.
879  *
880  * This function never returns
881  *
882  * @param exit_code
883  *     The exit code to be returned by the application
884  * @param format
885  *     The format string to be used for printing the message. This can include
886  *     printf format characters which will be expanded using any further parameters
887  *     to the function.
888  */
889 __rte_noreturn void
890 rte_exit(int exit_code, const char *format, ...)
891 	__rte_format_printf(2, 3);
892 
893 #ifdef __cplusplus
894 }
895 #endif
896 
897 #endif
898