456 ShouldNotReachHere();
457 return false;
458 }
459
460 void os::Linux::init_thread_fpu_state(void) {
461 // Nothing to do on z/Architecture.
462 }
463
464 int os::Linux::get_fpu_control_word(void) {
465 // Nothing to do on z/Architecture.
466 return 0;
467 }
468
469 void os::Linux::set_fpu_control_word(int fpu_control) {
470 // Nothing to do on z/Architecture.
471 }
472
473 ////////////////////////////////////////////////////////////////////////////////
474 // thread stack
475
476 // These sizes exclude OS stack guard pages, but include
477 // the VM guard pages.
478 size_t os::Posix::_compiler_thread_min_stack_allowed = 128 * K;
479 size_t os::Posix::_java_thread_min_stack_allowed = 128 * K;
480 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 128 * K;
481
482 // Return default stack size for thr_type.
483 size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
484 // Default stack size (compiler thread needs larger stack).
485 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1024 * K);
486 return s;
487 }
488
489 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
490 // Creating guard page is very expensive. Java thread has HotSpot
491 // guard page, only enable glibc guard page for non-Java threads.
492 return (thr_type == java_thread ? 0 : page_size());
493 }
494
495 // Java thread:
496 //
497 // Low memory addresses
498 // +------------------------+
499 // | |\
500 // | glibc guard page | - Right in the middle of stack, 2 pages
501 // | |/
502 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
503 // | |\
504 // | HotSpot Guard Pages | - red and yellow pages
505 // | |/
506 // +------------------------+ JavaThread::stack_yellow_zone_base()
507 // | |\
508 // | Normal Stack | -
509 // | |/
510 // P2 +------------------------+ Thread::stack_base()
511 //
512 // Non-Java thread:
|
456 ShouldNotReachHere();
457 return false;
458 }
459
460 void os::Linux::init_thread_fpu_state(void) {
461 // Nothing to do on z/Architecture.
462 }
463
464 int os::Linux::get_fpu_control_word(void) {
465 // Nothing to do on z/Architecture.
466 return 0;
467 }
468
469 void os::Linux::set_fpu_control_word(int fpu_control) {
470 // Nothing to do on z/Architecture.
471 }
472
473 ////////////////////////////////////////////////////////////////////////////////
474 // thread stack
475
476 // Minimum usable stack sizes required to get to user code. Space for VM
477 // guard pages is added later.
478 size_t os::Posix::_compiler_thread_min_stack_allowed = (52 DEBUG_ONLY(+32)) * K;
479 size_t os::Posix::_java_thread_min_stack_allowed = (32 DEBUG_ONLY(+8)) * K;
480 size_t os::Posix::_vm_internal_thread_min_stack_allowed = 32 * K;
481
482 // Return default stack size for thr_type.
483 size_t os::Posix::default_stack_size(os::ThreadType thr_type) {
484 // Default stack size (compiler thread needs larger stack).
485 size_t s = (thr_type == os::compiler_thread ? 4 * M : 1024 * K);
486 return s;
487 }
488
489 size_t os::Linux::default_guard_size(os::ThreadType thr_type) {
490 // Creating guard page is very expensive. Java thread has HotSpot
491 // guard page, only enable glibc guard page for non-Java threads.
492 return ((thr_type == java_thread || thr_type == os::compiler_thread) ? 0 : page_size());
493 }
494
495 // Java thread:
496 //
497 // Low memory addresses
498 // +------------------------+
499 // | |\
500 // | glibc guard page | - Right in the middle of stack, 2 pages
501 // | |/
502 // P1 +------------------------+ Thread::stack_base() - Thread::stack_size()
503 // | |\
504 // | HotSpot Guard Pages | - red and yellow pages
505 // | |/
506 // +------------------------+ JavaThread::stack_yellow_zone_base()
507 // | |\
508 // | Normal Stack | -
509 // | |/
510 // P2 +------------------------+ Thread::stack_base()
511 //
512 // Non-Java thread:
|