1 /*
   2  * Copyright (c) 1999, 2013, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef OS_LINUX_VM_OS_LINUX_HPP
  26 #define OS_LINUX_VM_OS_LINUX_HPP
  27 
  28 // Linux_OS defines the interface to Linux operating systems
  29 
  30 /* pthread_getattr_np comes with LinuxThreads-0.9-7 on RedHat 7.1 */
  31 typedef int (*pthread_getattr_func_type) (pthread_t, pthread_attr_t *);
  32 
  33 class Linux {
  34   friend class os;
  35 
  36   // For signal-chaining
  37 #define MAXSIGNUM 32
  38   static struct sigaction sigact[MAXSIGNUM]; // saved preinstalled sigactions
  39   static unsigned int sigs;             // mask of signals that have
  40                                         // preinstalled signal handlers
  41   static bool libjsig_is_loaded;        // libjsig that interposes sigaction(),
  42                                         // __sigaction(), signal() is loaded
  43   static struct sigaction *(*get_signal_action)(int);
  44   static struct sigaction *get_preinstalled_handler(int);
  45   static void save_preinstalled_handler(int, struct sigaction&);
  46 
  47   static void check_signal_handler(int sig);
  48 
  49   // For signal flags diagnostics
  50   static int sigflags[MAXSIGNUM];
  51 
  52   static int (*_clock_gettime)(clockid_t, struct timespec *);
  53   static int (*_pthread_getcpuclockid)(pthread_t, clockid_t *);
  54 
  55   static address   _initial_thread_stack_bottom;
  56   static uintptr_t _initial_thread_stack_size;
  57 
  58   static const char *_glibc_version;
  59   static const char *_libpthread_version;
  60 
  61   static bool _is_floating_stack;
  62   static bool _is_NPTL;
  63   static bool _supports_fast_thread_cpu_time;
  64 
  65   static GrowableArray<int>* _cpu_to_node;
  66 
  67  protected:
  68 
  69   static julong _physical_memory;
  70   static pthread_t _main_thread;
  71   static Mutex* _createThread_lock;
  72   static int _page_size;
  73   static const int _vm_default_page_size;
  74 
  75   static julong available_memory();
  76   static julong physical_memory() { return _physical_memory; }
  77   static void initialize_system_info();
  78 
  79   static void set_glibc_version(const char *s)      { _glibc_version = s; }
  80   static void set_libpthread_version(const char *s) { _libpthread_version = s; }
  81 
  82   static bool supports_variable_stack_size();
  83 
  84   static void set_is_NPTL()                   { _is_NPTL = true;  }
  85   static void set_is_LinuxThreads()           { _is_NPTL = false; }
  86   static void set_is_floating_stack()         { _is_floating_stack = true; }
  87 
  88   static void rebuild_cpu_to_node_map();
  89   static GrowableArray<int>* cpu_to_node()    { return _cpu_to_node; }
  90 
  91   static bool hugetlbfs_sanity_check(bool warn, size_t page_size);
  92 
  93   static void print_full_memory_info(outputStream* st);
  94   static void print_distro_info(outputStream* st);
  95   static void print_libversion_info(outputStream* st);
  96 
  97  public:
  98   static bool _stack_is_executable;
  99   static void *dlopen_helper(const char *name, char *ebuf, int ebuflen);
 100   static void *dll_load_in_vmthread(const char *name, char *ebuf, int ebuflen);
 101 
 102   static void init_thread_fpu_state();
 103   static int  get_fpu_control_word();
 104   static void set_fpu_control_word(int fpu_control);
 105   static pthread_t main_thread(void)                                { return _main_thread; }
 106   // returns kernel thread id (similar to LWP id on Solaris), which can be
 107   // used to access /proc
 108   static pid_t gettid();
 109   static void set_createThread_lock(Mutex* lk)                      { _createThread_lock = lk; }
 110   static Mutex* createThread_lock(void)                             { return _createThread_lock; }
 111   static void hotspot_sigmask(Thread* thread);
 112 
 113   static address   initial_thread_stack_bottom(void)                { return _initial_thread_stack_bottom; }
 114   static uintptr_t initial_thread_stack_size(void)                  { return _initial_thread_stack_size; }
 115   static bool is_initial_thread(void);
 116 
 117   static int page_size(void)                                        { return _page_size; }
 118   static void set_page_size(int val)                                { _page_size = val; }
 119 
 120   static int vm_default_page_size(void)                             { return _vm_default_page_size; }
 121 
 122   static address   ucontext_get_pc(ucontext_t* uc);
 123   static intptr_t* ucontext_get_sp(ucontext_t* uc);
 124   static intptr_t* ucontext_get_fp(ucontext_t* uc);
 125 
 126   // For Analyzer Forte AsyncGetCallTrace profiling support:
 127   //
 128   // This interface should be declared in os_linux_i486.hpp, but
 129   // that file provides extensions to the os class and not the
 130   // Linux class.
 131   static ExtendedPC fetch_frame_from_ucontext(Thread* thread, ucontext_t* uc,
 132     intptr_t** ret_sp, intptr_t** ret_fp);
 133 
 134   // This boolean allows users to forward their own non-matching signals
 135   // to JVM_handle_linux_signal, harmlessly.
 136   static bool signal_handlers_are_installed;
 137 
 138   static int get_our_sigflags(int);
 139   static void set_our_sigflags(int, int);
 140   static void signal_sets_init();
 141   static void install_signal_handlers();
 142   static void set_signal_handler(int, bool);
 143   static bool is_sig_ignored(int sig);
 144 
 145   static sigset_t* unblocked_signals();
 146   static sigset_t* vm_signals();
 147   static sigset_t* allowdebug_blocked_signals();
 148 
 149   // For signal-chaining
 150   static struct sigaction *get_chained_signal_action(int sig);
 151   static bool chained_handler(int sig, siginfo_t* siginfo, void* context);
 152 
 153   // GNU libc and libpthread version strings
 154   static const char *glibc_version()          { return _glibc_version; }
 155   static const char *libpthread_version()     { return _libpthread_version; }
 156 
 157   // NPTL or LinuxThreads?
 158   static bool is_LinuxThreads()               { return !_is_NPTL; }
 159   static bool is_NPTL()                       { return _is_NPTL;  }
 160 
 161   // NPTL is always floating stack. LinuxThreads could be using floating
 162   // stack or fixed stack.
 163   static bool is_floating_stack()             { return _is_floating_stack; }
 164 
 165   static void libpthread_init();
 166   static bool libnuma_init();
 167   static void* libnuma_dlsym(void* handle, const char* name);
 168   // Minimum stack size a thread can be created with (allowing
 169   // the VM to completely create the thread and enter user code)
 170   static size_t min_stack_allowed;
 171 
 172   // Return default stack size or guard size for the specified thread type
 173   static size_t default_stack_size(os::ThreadType thr_type);
 174   static size_t default_guard_size(os::ThreadType thr_type);
 175 
 176   static void capture_initial_stack(size_t max_size);
 177 
 178   // Stack overflow handling
 179   static bool manually_expand_stack(JavaThread * t, address addr);
 180   static int max_register_window_saves_before_flushing();
 181 
 182   // Real-time clock functions
 183   static void clock_init(void);
 184 
 185   // fast POSIX clocks support
 186   static void fast_thread_clock_init(void);
 187 
 188   static inline bool supports_monotonic_clock() {
 189     return _clock_gettime != NULL;
 190   }
 191 
 192   static int clock_gettime(clockid_t clock_id, struct timespec *tp) {
 193     return _clock_gettime ? _clock_gettime(clock_id, tp) : -1;
 194   }
 195 
 196   static int pthread_getcpuclockid(pthread_t tid, clockid_t *clock_id) {
 197     return _pthread_getcpuclockid ? _pthread_getcpuclockid(tid, clock_id) : -1;
 198   }
 199 
 200   static bool supports_fast_thread_cpu_time() {
 201     return _supports_fast_thread_cpu_time;
 202   }
 203 
 204   static jlong fast_thread_cpu_time(clockid_t clockid);
 205 
 206   // Stack repair handling
 207 
 208   // none present
 209 
 210   // LinuxThreads work-around for 6292965
 211   static int safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime);
 212 
 213 
 214   // Linux suspend/resume support - this helper is a shadow of its former
 215   // self now that low-level suspension is barely used, and old workarounds
 216   // for LinuxThreads are no longer needed.
 217   class SuspendResume {
 218   private:
 219     volatile int  _suspend_action;
 220     volatile jint _state;
 221   public:
 222     // values for suspend_action:
 223     enum {
 224       SR_NONE              = 0x00,
 225       SR_SUSPEND           = 0x01,  // suspend request
 226       SR_CONTINUE          = 0x02,  // resume request
 227       SR_SUSPENDED         = 0x20   // values for _state: + SR_NONE
 228     };
 229 
 230     SuspendResume() { _suspend_action = SR_NONE; _state = SR_NONE; }
 231 
 232     int suspend_action() const     { return _suspend_action; }
 233     void set_suspend_action(int x) { _suspend_action = x;    }
 234 
 235     // atomic updates for _state
 236     inline void set_suspended();
 237     inline void clear_suspended();
 238     bool is_suspended()            { return _state & SR_SUSPENDED;       }
 239 
 240   };
 241 
 242 private:
 243   typedef int (*sched_getcpu_func_t)(void);
 244   typedef int (*numa_node_to_cpus_func_t)(int node, unsigned long *buffer, int bufferlen);
 245   typedef int (*numa_max_node_func_t)(void);
 246   typedef int (*numa_available_func_t)(void);
 247   typedef int (*numa_tonode_memory_func_t)(void *start, size_t size, int node);
 248   typedef void (*numa_interleave_memory_func_t)(void *start, size_t size, unsigned long *nodemask);
 249 
 250   static sched_getcpu_func_t _sched_getcpu;
 251   static numa_node_to_cpus_func_t _numa_node_to_cpus;
 252   static numa_max_node_func_t _numa_max_node;
 253   static numa_available_func_t _numa_available;
 254   static numa_tonode_memory_func_t _numa_tonode_memory;
 255   static numa_interleave_memory_func_t _numa_interleave_memory;
 256   static unsigned long* _numa_all_nodes;
 257 
 258   static void set_sched_getcpu(sched_getcpu_func_t func) { _sched_getcpu = func; }
 259   static void set_numa_node_to_cpus(numa_node_to_cpus_func_t func) { _numa_node_to_cpus = func; }
 260   static void set_numa_max_node(numa_max_node_func_t func) { _numa_max_node = func; }
 261   static void set_numa_available(numa_available_func_t func) { _numa_available = func; }
 262   static void set_numa_tonode_memory(numa_tonode_memory_func_t func) { _numa_tonode_memory = func; }
 263   static void set_numa_interleave_memory(numa_interleave_memory_func_t func) { _numa_interleave_memory = func; }
 264   static void set_numa_all_nodes(unsigned long* ptr) { _numa_all_nodes = ptr; }
 265   static int sched_getcpu_syscall(void);
 266 public:
 267   static int sched_getcpu()  { return _sched_getcpu != NULL ? _sched_getcpu() : -1; }
 268   static int numa_node_to_cpus(int node, unsigned long *buffer, int bufferlen) {
 269     return _numa_node_to_cpus != NULL ? _numa_node_to_cpus(node, buffer, bufferlen) : -1;
 270   }
 271   static int numa_max_node() { return _numa_max_node != NULL ? _numa_max_node() : -1; }
 272   static int numa_available() { return _numa_available != NULL ? _numa_available() : -1; }
 273   static int numa_tonode_memory(void *start, size_t size, int node) {
 274     return _numa_tonode_memory != NULL ? _numa_tonode_memory(start, size, node) : -1;
 275   }
 276   static void numa_interleave_memory(void *start, size_t size) {
 277     if (_numa_interleave_memory != NULL && _numa_all_nodes != NULL) {
 278       _numa_interleave_memory(start, size, _numa_all_nodes);
 279     }
 280   }
 281   static int get_node_by_cpu(int cpu_id);
 282 };
 283 
 284 
 285 class PlatformEvent : public CHeapObj<mtInternal> {
 286   private:
 287     double CachePad [4] ;   // increase odds that _mutex is sole occupant of cache line
 288     volatile int _Event ;
 289     volatile int _nParked ;
 290     pthread_mutex_t _mutex  [1] ;
 291     pthread_cond_t  _cond   [1] ;
 292     double PostPad  [2] ;
 293     Thread * _Assoc ;
 294 
 295   public:       // TODO-FIXME: make dtor private
 296     ~PlatformEvent() { guarantee (0, "invariant") ; }
 297 
 298   public:
 299     PlatformEvent() {
 300       int status;
 301       status = pthread_cond_init (_cond, NULL);
 302       assert_status(status == 0, status, "cond_init");
 303       status = pthread_mutex_init (_mutex, NULL);
 304       assert_status(status == 0, status, "mutex_init");
 305       _Event   = 0 ;
 306       _nParked = 0 ;
 307       _Assoc   = NULL ;
 308     }
 309 
 310     // Use caution with reset() and fired() -- they may require MEMBARs
 311     void reset() { _Event = 0 ; }
 312     int  fired() { return _Event; }
 313     void park () ;
 314     void unpark () ;
 315     int  TryPark () ;
 316     int  park (jlong millis) ;
 317     void SetAssociation (Thread * a) { _Assoc = a ; }
 318 } ;
 319 
 320 class PlatformParker : public CHeapObj<mtInternal> {
 321   protected:
 322     pthread_mutex_t _mutex [1] ;
 323     pthread_cond_t  _cond  [1] ;
 324 
 325   public:       // TODO-FIXME: make dtor private
 326     ~PlatformParker() { guarantee (0, "invariant") ; }
 327 
 328   public:
 329     PlatformParker() {
 330       int status;
 331       status = pthread_cond_init (_cond, NULL);
 332       assert_status(status == 0, status, "cond_init");
 333       status = pthread_mutex_init (_mutex, NULL);
 334       assert_status(status == 0, status, "mutex_init");
 335     }
 336 } ;
 337 
 338 #endif // OS_LINUX_VM_OS_LINUX_HPP