1 /*
2 * Copyright 1997-2009 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 // os defines the interface to operating system; this includes traditional
26 // OS services (time, I/O) as well as other functionality with system-
27 // dependent code.
28
29 typedef void (*dll_func)(...);
30
31 class Thread;
32 class JavaThread;
33 class Event;
34 class DLL;
35 class FileHandle;
36 template<class E> class GrowableArray;
37
38 // %%%%% Moved ThreadState, START_FN, OSThread to new osThread.hpp. -- Rose
39
40 // Platform-independent error return values from OS functions
41 enum OSReturn {
42 OS_OK = 0, // Operation was successful
43 OS_ERR = -1, // Operation failed
44 OS_INTRPT = -2, // Operation was interrupted
45 OS_TIMEOUT = -3, // Operation timed out
46 OS_NOMEM = -5, // Operation failed for lack of memory
47 OS_NORESOURCE = -6 // Operation failed for lack of nonmemory resource
48 };
49
50 enum ThreadPriority { // JLS 20.20.1-3
51 NoPriority = -1, // Initial non-priority value
52 MinPriority = 1, // Minimum priority
53 NormPriority = 5, // Normal (non-daemon) priority
54 NearMaxPriority = 9, // High priority, used for VMThread
55 MaxPriority = 10 // Highest priority, used for WatcherThread
56 // ensures that VMThread doesn't starve profiler
57 };
58
59 // Typedef for structured exception handling support
60 typedef void (*java_call_t)(JavaValue* value, methodHandle* method, JavaCallArguments* args, Thread* thread);
61
62 class os: AllStatic {
63 public:
64 enum { page_sizes_max = 9 }; // Size of _page_sizes array (8 plus a sentinel)
65
66 private:
67 static OSThread* _starting_thread;
68 static address _polling_page;
69 static volatile int32_t * _mem_serialize_page;
70 static uintptr_t _serialize_page_mask;
71 public:
72 static size_t _page_sizes[page_sizes_max];
73
74 private:
75 static void init_page_sizes(size_t default_page_size) {
76 _page_sizes[0] = default_page_size;
77 _page_sizes[1] = 0; // sentinel
78 }
79
80 public:
81 static void init(void); // Called before command line parsing
82 static jint init_2(void); // Called after command line parsing
83
84 // File names are case-insensitive on windows only
85 // Override me as needed
86 static int file_name_strcmp(const char* s1, const char* s2);
87
88 static bool getenv(const char* name, char* buffer, int len);
89 static bool have_special_privileges();
90
91 static jlong javaTimeMillis();
92 static jlong javaTimeNanos();
93 static void javaTimeNanos_info(jvmtiTimerInfo *info_ptr);
94 static void run_periodic_checks();
95
96
97 // Returns the elapsed time in seconds since the vm started.
98 static double elapsedTime();
99
100 // Returns real time in seconds since an arbitrary point
101 // in the past.
102 static bool getTimesSecs(double* process_real_time,
103 double* process_user_time,
104 double* process_system_time);
105
106 // Interface to the performance counter
107 static jlong elapsed_counter();
108 static jlong elapsed_frequency();
109
110 // The "virtual time" of a thread is the amount of time a thread has
111 // actually run. The first function indicates whether the OS supports
112 // this functionality for the current thread, and if so:
113 // * the second enables vtime tracking (if that is required).
114 // * the third tells whether vtime is enabled.
115 // * the fourth returns the elapsed virtual time for the current
116 // thread.
117 static bool supports_vtime();
118 static bool enable_vtime();
119 static bool vtime_enabled();
120 static double elapsedVTime();
121
122 // Return current local time in a string (YYYY-MM-DD HH:MM:SS).
123 // It is MT safe, but not async-safe, as reading time zone
124 // information may require a lock on some platforms.
125 static char* local_time_string(char *buf, size_t buflen);
126 static struct tm* localtime_pd (const time_t* clock, struct tm* res);
127 // Fill in buffer with current local time as an ISO-8601 string.
128 // E.g., YYYY-MM-DDThh:mm:ss.mmm+zzzz.
129 // Returns buffer, or NULL if it failed.
130 static char* iso8601_time(char* buffer, size_t buffer_length);
131
132 // Interface for detecting multiprocessor system
133 static inline bool is_MP() {
134 assert(_processor_count > 0, "invalid processor count");
135 return _processor_count > 1;
136 }
137 static julong available_memory();
138 static julong physical_memory();
139 static julong allocatable_physical_memory(julong size);
140 static bool is_server_class_machine();
141
142 // number of CPUs
143 static int processor_count() {
144 return _processor_count;
145 }
146 static void set_processor_count(int count) { _processor_count = count; }
147
148 // Returns the number of CPUs this process is currently allowed to run on.
149 // Note that on some OSes this can change dynamically.
150 static int active_processor_count();
151
152 // Bind processes to processors.
153 // This is a two step procedure:
154 // first you generate a distribution of processes to processors,
155 // then you bind processes according to that distribution.
156 // Compute a distribution for number of processes to processors.
157 // Stores the processor id's into the distribution array argument.
158 // Returns true if it worked, false if it didn't.
159 static bool distribute_processes(uint length, uint* distribution);
160 // Binds the current process to a processor.
161 // Returns true if it worked, false if it didn't.
162 static bool bind_to_processor(uint processor_id);
163
164 // Interface for stack banging (predetect possible stack overflow for
165 // exception processing) There are guard pages, and above that shadow
166 // pages for stack overflow checking.
167 static bool uses_stack_guard_pages();
168 static bool allocate_stack_guard_pages();
169 static void bang_stack_shadow_pages();
170 static bool stack_shadow_pages_available(Thread *thread, methodHandle method);
171
172 // OS interface to Virtual Memory
173
174 // Return the default page size.
175 static int vm_page_size();
176
177 // Return the page size to use for a region of memory. The min_pages argument
178 // is a hint intended to limit fragmentation; it says the returned page size
179 // should be <= region_max_size / min_pages. Because min_pages is a hint,
180 // this routine may return a size larger than region_max_size / min_pages.
181 //
182 // The current implementation ignores min_pages if a larger page size is an
183 // exact multiple of both region_min_size and region_max_size. This allows
184 // larger pages to be used when doing so would not cause fragmentation; in
185 // particular, a single page can be used when region_min_size ==
186 // region_max_size == a supported page size.
187 static size_t page_size_for_region(size_t region_min_size,
188 size_t region_max_size,
189 uint min_pages);
190
191 // Method for tracing page sizes returned by the above method; enabled by
192 // TracePageSizes. The region_{min,max}_size parameters should be the values
193 // passed to page_size_for_region() and page_size should be the result of that
194 // call. The (optional) base and size parameters should come from the
195 // ReservedSpace base() and size() methods.
196 static void trace_page_sizes(const char* str, const size_t region_min_size,
197 const size_t region_max_size,
198 const size_t page_size,
199 const char* base = NULL,
200 const size_t size = 0) PRODUCT_RETURN;
201
202 static int vm_allocation_granularity();
203 static char* reserve_memory(size_t bytes, char* addr = 0,
204 size_t alignment_hint = 0);
205 static char* attempt_reserve_memory_at(size_t bytes, char* addr);
206 static void split_reserved_memory(char *base, size_t size,
207 size_t split, bool realloc);
208 static bool commit_memory(char* addr, size_t bytes,
209 bool executable = false);
210 static bool commit_memory(char* addr, size_t size, size_t alignment_hint,
211 bool executable = false);
212 static bool uncommit_memory(char* addr, size_t bytes);
213 static bool release_memory(char* addr, size_t bytes);
214
215 enum ProtType { MEM_PROT_NONE, MEM_PROT_READ, MEM_PROT_RW, MEM_PROT_RWX };
216 static bool protect_memory(char* addr, size_t bytes, ProtType prot,
217 bool is_committed = true);
218
219 static bool guard_memory(char* addr, size_t bytes);
220 static bool unguard_memory(char* addr, size_t bytes);
221 static bool create_stack_guard_pages(char* addr, size_t bytes);
222 static bool remove_stack_guard_pages(char* addr, size_t bytes);
223
224 static char* map_memory(int fd, const char* file_name, size_t file_offset,
225 char *addr, size_t bytes, bool read_only = false,
226 bool allow_exec = false);
227 static char* remap_memory(int fd, const char* file_name, size_t file_offset,
228 char *addr, size_t bytes, bool read_only,
229 bool allow_exec);
230 static bool unmap_memory(char *addr, size_t bytes);
231 static void free_memory(char *addr, size_t bytes);
232 static void realign_memory(char *addr, size_t bytes, size_t alignment_hint);
233
234 // NUMA-specific interface
235 static bool numa_has_static_binding();
236 static bool numa_has_group_homing();
237 static void numa_make_local(char *addr, size_t bytes, int lgrp_hint);
238 static void numa_make_global(char *addr, size_t bytes);
239 static size_t numa_get_groups_num();
240 static size_t numa_get_leaf_groups(int *ids, size_t size);
241 static bool numa_topology_changed();
242 static int numa_get_group_id();
243
244 // Page manipulation
245 struct page_info {
246 size_t size;
247 int lgrp_id;
248 };
249 static bool get_page_info(char *start, page_info* info);
250 static char* scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found);
251
252 static char* non_memory_address_word();
253 // reserve, commit and pin the entire memory region
254 static char* reserve_memory_special(size_t size, char* addr = NULL,
255 bool executable = false);
256 static bool release_memory_special(char* addr, size_t bytes);
257 static bool large_page_init();
258 static size_t large_page_size();
259 static bool can_commit_large_page_memory();
260 static bool can_execute_large_page_memory();
261
262 // OS interface to polling page
263 static address get_polling_page() { return _polling_page; }
264 static void set_polling_page(address page) { _polling_page = page; }
265 static bool is_poll_address(address addr) { return addr >= _polling_page && addr < (_polling_page + os::vm_page_size()); }
266 static void make_polling_page_unreadable();
267 static void make_polling_page_readable();
268
269 // Routines used to serialize the thread state without using membars
270 static void serialize_thread_states();
271
272 // Since we write to the serialize page from every thread, we
273 // want stores to be on unique cache lines whenever possible
274 // in order to minimize CPU cross talk. We pre-compute the
275 // amount to shift the thread* to make this offset unique to
276 // each thread.
277 static int get_serialize_page_shift_count() {
278 return SerializePageShiftCount;
279 }
280
281 static void set_serialize_page_mask(uintptr_t mask) {
282 _serialize_page_mask = mask;
283 }
284
285 static unsigned int get_serialize_page_mask() {
286 return _serialize_page_mask;
287 }
288
289 static void set_memory_serialize_page(address page);
290
291 static address get_memory_serialize_page() {
292 return (address)_mem_serialize_page;
293 }
294
295 static inline void write_memory_serialize_page(JavaThread *thread) {
296 uintptr_t page_offset = ((uintptr_t)thread >>
297 get_serialize_page_shift_count()) &
298 get_serialize_page_mask();
299 *(volatile int32_t *)((uintptr_t)_mem_serialize_page+page_offset) = 1;
300 }
301
302 static bool is_memory_serialize_page(JavaThread *thread, address addr) {
303 if (UseMembar) return false;
304 // Previously this function calculated the exact address of this
305 // thread's serialize page, and checked if the faulting address
306 // was equal. However, some platforms mask off faulting addresses
307 // to the page size, so now we just check that the address is
308 // within the page. This makes the thread argument unnecessary,
309 // but we retain the NULL check to preserve existing behaviour.
310 if (thread == NULL) return false;
311 address page = (address) _mem_serialize_page;
312 return addr >= page && addr < (page + os::vm_page_size());
313 }
314
315 static void block_on_serialize_page_trap();
316
317 // threads
318
319 enum ThreadType {
320 vm_thread,
321 cgc_thread, // Concurrent GC thread
322 pgc_thread, // Parallel GC thread
323 java_thread,
324 compiler_thread,
325 watcher_thread
326 };
327
328 static bool create_thread(Thread* thread,
329 ThreadType thr_type,
330 size_t stack_size = 0);
331 static bool create_main_thread(JavaThread* thread);
332 static bool create_attached_thread(JavaThread* thread);
333 static void pd_start_thread(Thread* thread);
334 static void start_thread(Thread* thread);
335
336 static void initialize_thread();
337 static void free_thread(OSThread* osthread);
338
339 // thread id on Linux/64bit is 64bit, on Windows and Solaris, it's 32bit
340 static intx current_thread_id();
341 static int current_process_id();
342 // hpi::read for calls from non native state
343 // For performance, hpi::read is only callable from _thread_in_native
344 static size_t read(int fd, void *buf, unsigned int nBytes);
345 static int sleep(Thread* thread, jlong ms, bool interruptable);
346 static int naked_sleep();
347 static void infinite_sleep(); // never returns, use with CAUTION
348 static void yield(); // Yields to all threads with same priority
349 enum YieldResult {
350 YIELD_SWITCHED = 1, // caller descheduled, other ready threads exist & ran
351 YIELD_NONEREADY = 0, // No other runnable/ready threads.
352 // platform-specific yield return immediately
353 YIELD_UNKNOWN = -1 // Unknown: platform doesn't support _SWITCHED or _NONEREADY
354 // YIELD_SWITCHED and YIELD_NONREADY imply the platform supports a "strong"
355 // yield that can be used in lieu of blocking.
356 } ;
357 static YieldResult NakedYield () ;
358 static void yield_all(int attempts = 0); // Yields to all other threads including lower priority
359 static void loop_breaker(int attempts); // called from within tight loops to possibly influence time-sharing
360 static OSReturn set_priority(Thread* thread, ThreadPriority priority);
361 static OSReturn get_priority(const Thread* const thread, ThreadPriority& priority);
362
363 static void interrupt(Thread* thread);
364 static bool is_interrupted(Thread* thread, bool clear_interrupted);
365
366 static int pd_self_suspend_thread(Thread* thread);
367
368 static ExtendedPC fetch_frame_from_context(void* ucVoid, intptr_t** sp, intptr_t** fp);
369 static frame fetch_frame_from_context(void* ucVoid);
370
371 static ExtendedPC get_thread_pc(Thread *thread);
372 static void breakpoint();
373
374 static address current_stack_pointer();
375 static address current_stack_base();
376 static size_t current_stack_size();
377
378 static int message_box(const char* title, const char* message);
379 static char* do_you_want_to_debug(const char* message);
380
381 // run cmd in a separate process and return its exit code; or -1 on failures
382 static int fork_and_exec(char *cmd);
383
384 // Set file to send error reports.
385 static void set_error_file(const char *logfile);
386
387 // os::exit() is merged with vm_exit()
388 // static void exit(int num);
389
390 // Terminate the VM, but don't exit the process
391 static void shutdown();
392
393 // Terminate with an error. Default is to generate a core file on platforms
394 // that support such things. This calls shutdown() and then aborts.
395 static void abort(bool dump_core = true);
396
397 // Die immediately, no exit hook, no abort hook, no cleanup.
398 static void die();
399
400 // Reading directories.
401 static DIR* opendir(const char* dirname);
402 static int readdir_buf_size(const char *path);
403 static struct dirent* readdir(DIR* dirp, dirent* dbuf);
404 static int closedir(DIR* dirp);
405
406 // Dynamic library extension
407 static const char* dll_file_extension();
408
409 static const char* get_temp_directory();
410 static const char* get_current_directory(char *buf, int buflen);
411
412 // Builds a platform-specific full library path given a ld path and lib name
413 static void dll_build_name(char* buffer, size_t size,
414 const char* pathname, const char* fname);
415
416 // Symbol lookup, find nearest function name; basically it implements
417 // dladdr() for all platforms. Name of the nearest function is copied
418 // to buf. Distance from its base address is returned as offset.
419 // If function name is not found, buf[0] is set to '\0' and offset is
420 // set to -1.
421 static bool dll_address_to_function_name(address addr, char* buf,
422 int buflen, int* offset);
423
424 // Locate DLL/DSO. On success, full path of the library is copied to
425 // buf, and offset is set to be the distance between addr and the
426 // library's base address. On failure, buf[0] is set to '\0' and
427 // offset is set to -1.
428 static bool dll_address_to_library_name(address addr, char* buf,
429 int buflen, int* offset);
430
431 // Find out whether the pc is in the static code for jvm.dll/libjvm.so.
432 static bool address_is_in_vm(address addr);
433
434 // Loads .dll/.so and
435 // in case of error it checks if .dll/.so was built for the
436 // same architecture as Hotspot is running on
437 static void* dll_load(const char *name, char *ebuf, int ebuflen);
438
439 // lookup symbol in a shared library
440 static void* dll_lookup(void* handle, const char* name);
441
442 // Print out system information; they are called by fatal error handler.
443 // Output format may be different on different platforms.
444 static void print_os_info(outputStream* st);
445 static void print_cpu_info(outputStream* st);
446 static void print_memory_info(outputStream* st);
447 static void print_dll_info(outputStream* st);
448 static void print_environment_variables(outputStream* st, const char** env_list, char* buffer, int len);
449 static void print_context(outputStream* st, void* context);
450 static void print_siginfo(outputStream* st, void* siginfo);
451 static void print_signal_handlers(outputStream* st, char* buf, size_t buflen);
452 static void print_date_and_time(outputStream* st);
453
454 // The following two functions are used by fatal error handler to trace
455 // native (C) frames. They are not part of frame.hpp/frame.cpp because
456 // frame.hpp/cpp assume thread is JavaThread, and also because different
457 // OS/compiler may have different convention or provide different API to
458 // walk C frames.
459 //
460 // We don't attempt to become a debugger, so we only follow frames if that
461 // does not require a lookup in the unwind table, which is part of the binary
462 // file but may be unsafe to read after a fatal error. So on x86, we can
463 // only walk stack if %ebp is used as frame pointer; on ia64, it's not
464 // possible to walk C stack without having the unwind table.
465 static bool is_first_C_frame(frame *fr);
466 static frame get_sender_for_C_frame(frame *fr);
467
468 // return current frame. pc() and sp() are set to NULL on failure.
469 static frame current_frame();
470
471 static void print_hex_dump(outputStream* st, address start, address end, int unitsize);
472
473 // returns a string to describe the exception/signal;
474 // returns NULL if exception_code is not an OS exception/signal.
475 static const char* exception_name(int exception_code, char* buf, size_t buflen);
476
477 // Returns native Java library, loads if necessary
478 static void* native_java_library();
479
480 // Fills in path to jvm.dll/libjvm.so (this info used to find hpi).
481 static void jvm_path(char *buf, jint buflen);
482
483 // JNI names
484 static void print_jni_name_prefix_on(outputStream* st, int args_size);
485 static void print_jni_name_suffix_on(outputStream* st, int args_size);
486
487 // File conventions
488 static const char* file_separator();
489 static const char* line_separator();
490 static const char* path_separator();
491
492 // Init os specific system properties values
493 static void init_system_properties_values();
494
495 // IO operations, non-JVM_ version.
496 static int stat(const char* path, struct stat* sbuf);
497 static bool dir_is_empty(const char* path);
498
499 // IO operations on binary files
500 static int create_binary_file(const char* path, bool rewrite_existing);
501 static jlong current_file_offset(int fd);
502 static jlong seek_to_file_offset(int fd, jlong offset);
503
504 // Thread Local Storage
505 static int allocate_thread_local_storage();
506 static void thread_local_storage_at_put(int index, void* value);
507 static void* thread_local_storage_at(int index);
508 static void free_thread_local_storage(int index);
509
510 // General allocation (must be MT-safe)
511 static void* malloc (size_t size);
512 static void* realloc (void *memblock, size_t size);
513 static void free (void *memblock);
514 static bool check_heap(bool force = false); // verify C heap integrity
515 static char* strdup(const char *); // Like strdup
516
517 #ifndef PRODUCT
518 static int num_mallocs; // # of calls to malloc/realloc
519 static size_t alloc_bytes; // # of bytes allocated
520 static int num_frees; // # of calls to free
521 #endif
522
523 // Printing 64 bit integers
524 static const char* jlong_format_specifier();
525 static const char* julong_format_specifier();
526
527 // Support for signals (see JVM_RaiseSignal, JVM_RegisterSignal)
528 static void signal_init();
529 static void signal_init_pd();
530 static void signal_notify(int signal_number);
531 static void* signal(int signal_number, void* handler);
532 static void signal_raise(int signal_number);
533 static int signal_wait();
534 static int signal_lookup();
535 static void* user_handler();
536 static void terminate_signal_thread();
537 static int sigexitnum_pd();
538
539 // random number generation
540 static long random(); // return 32bit pseudorandom number
541 static void init_random(long initval); // initialize random sequence
542
543 // Structured OS Exception support
544 static void os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method, JavaCallArguments* args, Thread* thread);
545
546 // JVMTI & JVM monitoring and management support
547 // The thread_cpu_time() and current_thread_cpu_time() are only
548 // supported if is_thread_cpu_time_supported() returns true.
549 // They are not supported on Solaris T1.
550
551 // Thread CPU Time - return the fast estimate on a platform
552 // On Solaris - call gethrvtime (fast) - user time only
553 // On Linux - fast clock_gettime where available - user+sys
554 // - otherwise: very slow /proc fs - user+sys
555 // On Windows - GetThreadTimes - user+sys
556 static jlong current_thread_cpu_time();
557 static jlong thread_cpu_time(Thread* t);
558
559 // Thread CPU Time with user_sys_cpu_time parameter.
560 //
561 // If user_sys_cpu_time is true, user+sys time is returned.
562 // Otherwise, only user time is returned
563 static jlong current_thread_cpu_time(bool user_sys_cpu_time);
564 static jlong thread_cpu_time(Thread* t, bool user_sys_cpu_time);
565
566 // Return a bunch of info about the timers.
567 // Note that the returned info for these two functions may be different
568 // on some platforms
569 static void current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr);
570 static void thread_cpu_time_info(jvmtiTimerInfo *info_ptr);
571
572 static bool is_thread_cpu_time_supported();
573
574 // System loadavg support. Returns -1 if load average cannot be obtained.
575 static int loadavg(double loadavg[], int nelem);
576
577 // Hook for os specific jvm options that we don't want to abort on seeing
578 static bool obsolete_option(const JavaVMOption *option);
579
580 // Platform dependent stuff
581 #include "incls/_os_pd.hpp.incl"
582
583 // debugging support (mostly used by debug.cpp)
584 static bool find(address pc) PRODUCT_RETURN0; // OS specific function to make sense out of an address
585
586 static bool dont_yield(); // when true, JVM_Yield() is nop
587 static void print_statistics();
588
589 // Thread priority helpers (implemented in OS-specific part)
590 static OSReturn set_native_priority(Thread* thread, int native_prio);
591 static OSReturn get_native_priority(const Thread* const thread, int* priority_ptr);
592 static int java_to_os_priority[MaxPriority + 1];
593 // Hint to the underlying OS that a task switch would not be good.
594 // Void return because it's a hint and can fail.
595 static void hint_no_preempt();
596
597 // Used at creation if requested by the diagnostic flag PauseAtStartup.
598 // Causes the VM to wait until an external stimulus has been applied
599 // (for Unix, that stimulus is a signal, for Windows, an external
600 // ResumeThread call)
601 static void pause();
602
603 protected:
604 static long _rand_seed; // seed for random number generator
605 static int _processor_count; // number of processors
606
607 static char* format_boot_path(const char* format_string,
608 const char* home,
609 int home_len,
610 char fileSep,
611 char pathSep);
612 static bool set_boot_path(char fileSep, char pathSep);
613 static char** split_path(const char* path, int* n);
614 };
615
616 // Note that "PAUSE" is almost always used with synchronization
617 // so arguably we should provide Atomic::SpinPause() instead
618 // of the global SpinPause() with C linkage.
619 // It'd also be eligible for inlining on many platforms.
620
621 extern "C" int SpinPause () ;
622 extern "C" int SafeFetch32 (int * adr, int errValue) ;
623 extern "C" intptr_t SafeFetchN (intptr_t * adr, intptr_t errValue) ;