hotspot/src/os/linux/vm/os_linux.hpp - platform/libcore - Git at Google

 /*
  * Copyright 1999-2007 Sun Microsystems, Inc.  All Rights Reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  *
  */

 // Linux_OS defines the interface to Linux operating systems

 /* pthread_getattr_np comes with LinuxThreads-0.9-7 on RedHat 7.1 */
 typedef int (*pthread_getattr_func_type) (pthread_t, pthread_attr_t *);

 class Linux {
   friend class os;

   // For signal-chaining
 #define MAXSIGNUM 32
   static struct sigaction sigact[MAXSIGNUM]; // saved preinstalled sigactions
   static unsigned int sigs;             // mask of signals that have
                                         // preinstalled signal handlers
   static bool libjsig_is_loaded;        // libjsig that interposes sigaction(),
                                         // __sigaction(), signal() is loaded
   static struct sigaction *(*get_signal_action)(int);
   static struct sigaction *get_preinstalled_handler(int);
   static void save_preinstalled_handler(int, struct sigaction&);

   static void check_signal_handler(int sig);

   // For signal flags diagnostics
   static int sigflags[MAXSIGNUM];

   static int (*_clock_gettime)(clockid_t, struct timespec *);
   static int (*_pthread_getcpuclockid)(pthread_t, clockid_t *);

   static address   _initial_thread_stack_bottom;
   static uintptr_t _initial_thread_stack_size;

   static char *_glibc_version;
   static char *_libpthread_version;

   static bool _is_floating_stack;
   static bool _is_NPTL;
   static bool _supports_fast_thread_cpu_time;

  protected:

   static julong _physical_memory;
   static pthread_t _main_thread;
   static Mutex* _createThread_lock;
   static int _page_size;

   static julong available_memory();
   static julong physical_memory() { return _physical_memory; }
   static void initialize_system_info();

   static void set_glibc_version(char *s)      { _glibc_version = s; }
   static void set_libpthread_version(char *s) { _libpthread_version = s; }

   static bool supports_variable_stack_size();

   static void set_is_NPTL()                   { _is_NPTL = true;  }
   static void set_is_LinuxThreads()           { _is_NPTL = false; }
   static void set_is_floating_stack()         { _is_floating_stack = true; }

  public:

   static void init_thread_fpu_state();
   static int  get_fpu_control_word();
   static void set_fpu_control_word(int fpu_control);
   static pthread_t main_thread(void)                                { return _main_thread; }
   // returns kernel thread id (similar to LWP id on Solaris), which can be
   // used to access /proc
   static pid_t gettid();
   static void set_createThread_lock(Mutex* lk)                      { _createThread_lock = lk; }
   static Mutex* createThread_lock(void)                             { return _createThread_lock; }
   static void hotspot_sigmask(Thread* thread);

   static address   initial_thread_stack_bottom(void)                { return _initial_thread_stack_bottom; }
   static uintptr_t initial_thread_stack_size(void)                  { return _initial_thread_stack_size; }
   static bool is_initial_thread(void);

   static int page_size(void)                                        { return _page_size; }
   static void set_page_size(int val)                                { _page_size = val; }

   static address   ucontext_get_pc(ucontext_t* uc);
   static intptr_t* ucontext_get_sp(ucontext_t* uc);
   static intptr_t* ucontext_get_fp(ucontext_t* uc);

   // For Analyzer Forte AsyncGetCallTrace profiling support:
   //
   // This interface should be declared in os_linux_i486.hpp, but
   // that file provides extensions to the os class and not the
   // Linux class.
   static ExtendedPC fetch_frame_from_ucontext(Thread* thread, ucontext_t* uc,
     intptr_t** ret_sp, intptr_t** ret_fp);

   // This boolean allows users to forward their own non-matching signals
   // to JVM_handle_linux_signal, harmlessly.
   static bool signal_handlers_are_installed;

   static int get_our_sigflags(int);
   static void set_our_sigflags(int, int);
   static void signal_sets_init();
   static void install_signal_handlers();
   static void set_signal_handler(int, bool);
   static bool is_sig_ignored(int sig);

   static sigset_t* unblocked_signals();
   static sigset_t* vm_signals();
   static sigset_t* allowdebug_blocked_signals();

   // For signal-chaining
   static struct sigaction *get_chained_signal_action(int sig);
   static bool chained_handler(int sig, siginfo_t* siginfo, void* context);

   // GNU libc and libpthread version strings
   static char *glibc_version()                { return _glibc_version; }
   static char *libpthread_version()           { return _libpthread_version; }

   // NPTL or LinuxThreads?
   static bool is_LinuxThreads()               { return !_is_NPTL; }
   static bool is_NPTL()                       { return _is_NPTL;  }

   // NPTL is always floating stack. LinuxThreads could be using floating
   // stack or fixed stack.
   static bool is_floating_stack()             { return _is_floating_stack; }

   static void libpthread_init();

   // Minimum stack size a thread can be created with (allowing
   // the VM to completely create the thread and enter user code)
   static size_t min_stack_allowed;

   // Return default stack size or guard size for the specified thread type
   static size_t default_stack_size(os::ThreadType thr_type);
   static size_t default_guard_size(os::ThreadType thr_type);

   static void capture_initial_stack(size_t max_size);

   // Stack overflow handling
   static bool manually_expand_stack(JavaThread * t, address addr);
   static int max_register_window_saves_before_flushing();

   // Real-time clock functions
   static void clock_init(void);

   // fast POSIX clocks support
   static void fast_thread_clock_init(void);

   static bool supports_monotonic_clock() {
     return _clock_gettime != NULL;
   }

   static int clock_gettime(clockid_t clock_id, struct timespec *tp) {
     return _clock_gettime ? _clock_gettime(clock_id, tp) : -1;
   }

   static int pthread_getcpuclockid(pthread_t tid, clockid_t *clock_id) {
     return _pthread_getcpuclockid ? _pthread_getcpuclockid(tid, clock_id) : -1;
   }

   static bool supports_fast_thread_cpu_time() {
     return _supports_fast_thread_cpu_time;
   }

   static jlong fast_thread_cpu_time(clockid_t clockid);

   // Stack repair handling

   // none present

   // LinuxThreads work-around for 6292965
   static int safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime);


   // Linux suspend/resume support - this helper is a shadow of its former
   // self now that low-level suspension is barely used, and old workarounds
   // for LinuxThreads are no longer needed.
   class SuspendResume {
   private:
     volatile int _suspend_action;
     // values for suspend_action:
     #define SR_NONE               (0x00)
     #define SR_SUSPEND            (0x01)  // suspend request
     #define SR_CONTINUE           (0x02)  // resume request

     volatile jint _state;
     // values for _state: + SR_NONE
     #define SR_SUSPENDED          (0x20)
   public:
     SuspendResume() { _suspend_action = SR_NONE; _state = SR_NONE; }

     int suspend_action() const     { return _suspend_action; }
     void set_suspend_action(int x) { _suspend_action = x;    }

     // atomic updates for _state
     void set_suspended()           {
       jint temp, temp2;
       do {
         temp = _state;
         temp2 = Atomic::cmpxchg(temp | SR_SUSPENDED, &_state, temp);
       } while (temp2 != temp);
     }
     void clear_suspended()        {
       jint temp, temp2;
       do {
         temp = _state;
         temp2 = Atomic::cmpxchg(temp & ~SR_SUSPENDED, &_state, temp);
       } while (temp2 != temp);
     }
     bool is_suspended()            { return _state & SR_SUSPENDED;       }

     #undef SR_SUSPENDED
   };
 };


 class PlatformEvent : public CHeapObj {
   private:
     double CachePad [4] ;   // increase odds that _mutex is sole occupant of cache line
     volatile int _Event ;
     volatile int _nParked ;
     pthread_mutex_t _mutex  [1] ;
     pthread_cond_t  _cond   [1] ;
     double PostPad  [2] ;
     Thread * _Assoc ;

   public:       // TODO-FIXME: make dtor private
     ~PlatformEvent() { guarantee (0, "invariant") ; }

   public:
     PlatformEvent() {
       int status;
       status = pthread_cond_init (_cond, NULL);
       assert_status(status == 0, status, "cond_init");
       status = pthread_mutex_init (_mutex, NULL);
       assert_status(status == 0, status, "mutex_init");
       _Event   = 0 ;
       _nParked = 0 ;
       _Assoc   = NULL ;
     }

     // Use caution with reset() and fired() -- they may require MEMBARs
     void reset() { _Event = 0 ; }
     int  fired() { return _Event; }
     void park () ;
     void unpark () ;
     int  TryPark () ;
     int  park (jlong millis) ;
     void SetAssociation (Thread * a) { _Assoc = a ; }
 } ;

 class PlatformParker : public CHeapObj {
   protected:
     pthread_mutex_t _mutex [1] ;
     pthread_cond_t  _cond  [1] ;

   public:       // TODO-FIXME: make dtor private
     ~PlatformParker() { guarantee (0, "invariant") ; }

   public:
     PlatformParker() {
       int status;
       status = pthread_cond_init (_cond, NULL);
       assert_status(status == 0, status, "cond_init");
       status = pthread_mutex_init (_mutex, NULL);
       assert_status(status == 0, status, "mutex_init");
     }
 } ;
	/*
	* Copyright 1999-2007 Sun Microsystems, Inc. All Rights Reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
	* CA 95054 USA or visit www.sun.com if you need additional information or
	* have any questions.
	*
	*/

	// Linux_OS defines the interface to Linux operating systems

	/* pthread_getattr_np comes with LinuxThreads-0.9-7 on RedHat 7.1 */
	typedef int (pthread_getattr_func_type) (pthread_t, pthread_attr_t );

	class Linux {
	friend class os;

	// For signal-chaining
	#define MAXSIGNUM 32
	static struct sigaction sigact[MAXSIGNUM]; // saved preinstalled sigactions
	static unsigned int sigs; // mask of signals that have
	// preinstalled signal handlers
	static bool libjsig_is_loaded; // libjsig that interposes sigaction(),
	// __sigaction(), signal() is loaded
	static struct sigaction (get_signal_action)(int);
	static struct sigaction *get_preinstalled_handler(int);
	static void save_preinstalled_handler(int, struct sigaction&);

	static void check_signal_handler(int sig);

	// For signal flags diagnostics
	static int sigflags[MAXSIGNUM];

	static int (_clock_gettime)(clockid_t, struct timespec );
	static int (_pthread_getcpuclockid)(pthread_t, clockid_t );

	static address _initial_thread_stack_bottom;
	static uintptr_t _initial_thread_stack_size;

	static char *_glibc_version;
	static char *_libpthread_version;

	static bool _is_floating_stack;
	static bool _is_NPTL;
	static bool _supports_fast_thread_cpu_time;

	protected:

	static julong _physical_memory;
	static pthread_t _main_thread;
	static Mutex* _createThread_lock;
	static int _page_size;

	static julong available_memory();
	static julong physical_memory() { return _physical_memory; }
	static void initialize_system_info();

	static void set_glibc_version(char *s) { _glibc_version = s; }
	static void set_libpthread_version(char *s) { _libpthread_version = s; }

	static bool supports_variable_stack_size();

	static void set_is_NPTL() { _is_NPTL = true; }
	static void set_is_LinuxThreads() { _is_NPTL = false; }
	static void set_is_floating_stack() { _is_floating_stack = true; }

	public:

	static void init_thread_fpu_state();
	static int get_fpu_control_word();
	static void set_fpu_control_word(int fpu_control);
	static pthread_t main_thread(void) { return _main_thread; }
	// returns kernel thread id (similar to LWP id on Solaris), which can be
	// used to access /proc
	static pid_t gettid();
	static void set_createThread_lock(Mutex* lk) { _createThread_lock = lk; }
	static Mutex* createThread_lock(void) { return _createThread_lock; }
	static void hotspot_sigmask(Thread* thread);

	static address initial_thread_stack_bottom(void) { return _initial_thread_stack_bottom; }
	static uintptr_t initial_thread_stack_size(void) { return _initial_thread_stack_size; }
	static bool is_initial_thread(void);

	static int page_size(void) { return _page_size; }
	static void set_page_size(int val) { _page_size = val; }

	static address ucontext_get_pc(ucontext_t* uc);
	static intptr_t* ucontext_get_sp(ucontext_t* uc);
	static intptr_t* ucontext_get_fp(ucontext_t* uc);

	// For Analyzer Forte AsyncGetCallTrace profiling support:
	//
	// This interface should be declared in os_linux_i486.hpp, but
	// that file provides extensions to the os class and not the
	// Linux class.
	static ExtendedPC fetch_frame_from_ucontext(Thread* thread, ucontext_t* uc,
	intptr_t ret_sp, intptr_t ret_fp);

	// This boolean allows users to forward their own non-matching signals
	// to JVM_handle_linux_signal, harmlessly.
	static bool signal_handlers_are_installed;

	static int get_our_sigflags(int);
	static void set_our_sigflags(int, int);
	static void signal_sets_init();
	static void install_signal_handlers();
	static void set_signal_handler(int, bool);
	static bool is_sig_ignored(int sig);

	static sigset_t* unblocked_signals();
	static sigset_t* vm_signals();
	static sigset_t* allowdebug_blocked_signals();

	// For signal-chaining
	static struct sigaction *get_chained_signal_action(int sig);
	static bool chained_handler(int sig, siginfo_t* siginfo, void* context);

	// GNU libc and libpthread version strings
	static char *glibc_version() { return _glibc_version; }
	static char *libpthread_version() { return _libpthread_version; }

	// NPTL or LinuxThreads?
	static bool is_LinuxThreads() { return !_is_NPTL; }
	static bool is_NPTL() { return _is_NPTL; }

	// NPTL is always floating stack. LinuxThreads could be using floating
	// stack or fixed stack.
	static bool is_floating_stack() { return _is_floating_stack; }

	static void libpthread_init();

	// Minimum stack size a thread can be created with (allowing
	// the VM to completely create the thread and enter user code)
	static size_t min_stack_allowed;

	// Return default stack size or guard size for the specified thread type
	static size_t default_stack_size(os::ThreadType thr_type);
	static size_t default_guard_size(os::ThreadType thr_type);

	static void capture_initial_stack(size_t max_size);

	// Stack overflow handling
	static bool manually_expand_stack(JavaThread * t, address addr);
	static int max_register_window_saves_before_flushing();

	// Real-time clock functions
	static void clock_init(void);

	// fast POSIX clocks support
	static void fast_thread_clock_init(void);

	static bool supports_monotonic_clock() {
	return _clock_gettime != NULL;
	}

	static int clock_gettime(clockid_t clock_id, struct timespec *tp) {
	return _clock_gettime ? _clock_gettime(clock_id, tp) : -1;
	}

	static int pthread_getcpuclockid(pthread_t tid, clockid_t *clock_id) {
	return _pthread_getcpuclockid ? _pthread_getcpuclockid(tid, clock_id) : -1;
	}

	static bool supports_fast_thread_cpu_time() {
	return _supports_fast_thread_cpu_time;
	}

	static jlong fast_thread_cpu_time(clockid_t clockid);

	// Stack repair handling

	// none present

	// LinuxThreads work-around for 6292965
	static int safe_cond_timedwait(pthread_cond_t _cond, pthread_mutex_t _mutex, const struct timespec *_abstime);


	// Linux suspend/resume support - this helper is a shadow of its former
	// self now that low-level suspension is barely used, and old workarounds
	// for LinuxThreads are no longer needed.
	class SuspendResume {
	private:
	volatile int _suspend_action;
	// values for suspend_action:
	#define SR_NONE (0x00)
	#define SR_SUSPEND (0x01) // suspend request
	#define SR_CONTINUE (0x02) // resume request

	volatile jint _state;
	// values for _state: + SR_NONE
	#define SR_SUSPENDED (0x20)
	public:
	SuspendResume() { _suspend_action = SR_NONE; _state = SR_NONE; }

	int suspend_action() const { return _suspend_action; }
	void set_suspend_action(int x) { _suspend_action = x; }

	// atomic updates for _state
	void set_suspended() {
	jint temp, temp2;
	do {
	temp = _state;
	temp2 = Atomic::cmpxchg(temp \| SR_SUSPENDED, &_state, temp);
	} while (temp2 != temp);
	}
	void clear_suspended() {
	jint temp, temp2;
	do {
	temp = _state;
	temp2 = Atomic::cmpxchg(temp & ~SR_SUSPENDED, &_state, temp);
	} while (temp2 != temp);
	}
	bool is_suspended() { return _state & SR_SUSPENDED; }

	#undef SR_SUSPENDED
	};
	};


	class PlatformEvent : public CHeapObj {
	private:
	double CachePad [4] ; // increase odds that _mutex is sole occupant of cache line
	volatile int _Event ;
	volatile int _nParked ;
	pthread_mutex_t _mutex [1] ;
	pthread_cond_t _cond [1] ;
	double PostPad [2] ;
	Thread * _Assoc ;

	public: // TODO-FIXME: make dtor private
	~PlatformEvent() { guarantee (0, "invariant") ; }

	public:
	PlatformEvent() {
	int status;
	status = pthread_cond_init (_cond, NULL);
	assert_status(status == 0, status, "cond_init");
	status = pthread_mutex_init (_mutex, NULL);
	assert_status(status == 0, status, "mutex_init");
	_Event = 0 ;
	_nParked = 0 ;
	_Assoc = NULL ;
	}

	// Use caution with reset() and fired() -- they may require MEMBARs
	void reset() { _Event = 0 ; }
	int fired() { return _Event; }
	void park () ;
	void unpark () ;
	int TryPark () ;
	int park (jlong millis) ;
	void SetAssociation (Thread * a) { _Assoc = a ; }
	} ;

	class PlatformParker : public CHeapObj {
	protected:
	pthread_mutex_t _mutex [1] ;
	pthread_cond_t _cond [1] ;

	public: // TODO-FIXME: make dtor private
	~PlatformParker() { guarantee (0, "invariant") ; }

	public:
	PlatformParker() {
	int status;
	status = pthread_cond_init (_cond, NULL);
	assert_status(status == 0, status, "cond_init");
	status = pthread_mutex_init (_mutex, NULL);
	assert_status(status == 0, status, "mutex_init");
	}
	} ;