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hotspot/src/os/linux/vm/os_linux.hpp

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+/*
+ * 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");
+    }
+} ;