Changes in src/libcfa/concurrency/preemption.c [d0a045c7:65deb18]

File:

• src/libcfa/concurrency/preemption.c (modified) (11 diffs)

src/libcfa/concurrency/preemption.c

@@ -10 +10 @@
 // Created On       : Mon Jun 5 14:20:42 2017
 // Last Modified By : Peter A. Buhr
-// Last Modified On : Tue Jan 23 17:59:30 2018
-// Update Count     : 7
+// Last Modified On : Fri Jul 21 22:36:05 2017
+// Update Count     : 2
 //
 
 #include "preemption.h"
 
-#define ftype `ftype`
 extern "C" {
 #include <errno.h>
+#include <execinfo.h>
+#define __USE_GNU
+#include <signal.h>
+#undef __USE_GNU
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
 }
-#undef ftype
-
-#include "bits/signal.h"
+
+
+#ifdef __USE_STREAM__
+#include "fstream"
+#endif
 
 //TODO move to defaults
@@ -34 +39 @@
         return __CFA_DEFAULT_PREEMPTION__;
 }
+
+// Short hands for signal context information
+#define __CFA_SIGCXT__ ucontext_t *
+#define __CFA_SIGPARMS__ __attribute__((unused)) int sig, __attribute__((unused)) siginfo_t *sfp, __attribute__((unused)) __CFA_SIGCXT__ cxt
 
 // FwdDeclarations : timeout handlers
@@ -44 +53 @@
 void sigHandler_abort    ( __CFA_SIGPARMS__ );
 
+// FwdDeclarations : sigaction wrapper
+static void __kernel_sigaction( int sig, void (*handler)(__CFA_SIGPARMS__), int flags );
+
 // FwdDeclarations : alarm thread main
 void * alarm_loop( __attribute__((unused)) void * args );
 
 // Machine specific register name
-#if   defined(__x86_64__)
-#define CFA_REG_IP gregs[REG_RIP]
-#elif defined(__i386__)
-#define CFA_REG_IP gregs[REG_EIP]
-#elif defined(__ARM_ARCH__)
-#define CFA_REG_IP arm_pc
+#ifdef __x86_64__
+#define CFA_REG_IP REG_RIP
+#else
+#define CFA_REG_IP REG_EIP
 #endif
 
@@ -142 +152 @@
         // Disable interrupts by incrementing the counter
         void disable_interrupts() {
-                preemption_enabled = false;
-                __attribute__((unused)) unsigned short new_val = disable_preempt_count + 1;
-                disable_preempt_count = new_val;
+                __attribute__((unused)) unsigned short new_val = __atomic_add_fetch_2( &disable_preempt_count, 1, __ATOMIC_SEQ_CST );
                 verify( new_val < 65_000u );              // If this triggers someone is disabling interrupts without enabling them
         }
@@ -154 +162 @@
                 thread_desc * thrd = this_thread;         // Cache the thread now since interrupts can start happening after the atomic add
 
-                unsigned short prev = disable_preempt_count;
-                disable_preempt_count -= 1;
+                unsigned short prev = __atomic_fetch_add_2( &disable_preempt_count, -1, __ATOMIC_SEQ_CST );
                 verify( prev != 0u );                     // If this triggers someone is enabled already enabled interruptsverify( prev != 0u );
 
                 // Check if we need to prempt the thread because an interrupt was missed
-                if( prev == 1 ) {
-                        preemption_enabled = true;
-                        if( proc->pending_preemption ) {
-                                proc->pending_preemption = false;
-                                BlockInternal( thrd );
-                        }
+                if( prev == 1 && proc->pending_preemption ) {
+                        proc->pending_preemption = false;
+                        BlockInternal( thrd );
                 }
 
@@ -174 +178 @@
         // Don't execute any pending CtxSwitch even if counter reaches 0
         void enable_interrupts_noPoll() {
-                unsigned short prev = disable_preempt_count;
-                disable_preempt_count -= 1;
-                verifyf( prev != 0u, "Incremented from %u\n", prev );                     // If this triggers someone is enabled already enabled interrupts
-                if( prev == 1 ) {
-                        preemption_enabled = true;
-                }
+                __attribute__((unused)) unsigned short prev = __atomic_fetch_add_2( &disable_preempt_count, -1, __ATOMIC_SEQ_CST );
+                verify( prev != 0u );                     // If this triggers someone is enabled already enabled interrupts
         }
 }
@@ -220 +220 @@
 // If false : preemption is unsafe and marked as pending
 static inline bool preemption_ready() {
-        bool ready = preemption_enabled && !preemption_in_progress; // Check if preemption is safe
+        bool ready = disable_preempt_count == 0 && !preemption_in_progress; // Check if preemption is safe
         this_processor->pending_preemption = !ready;                        // Adjust the pending flag accordingly
         return ready;
@@ -235 +235 @@
 
         // Start with preemption disabled until ready
-        preemption_enabled = false;
         disable_preempt_count = 1;
 
@@ -244 +243 @@
         // Setup proper signal handlers
         __kernel_sigaction( SIGUSR1, sigHandler_ctxSwitch, SA_SIGINFO | SA_RESTART );         // CtxSwitch handler
+        // __kernel_sigaction( SIGSEGV, sigHandler_segv     , SA_SIGINFO );      // Failure handler
+        // __kernel_sigaction( SIGBUS , sigHandler_segv     , SA_SIGINFO );      // Failure handler
 
         signal_block( SIGALRM );
@@ -295 +296 @@
 // Receives SIGUSR1 signal and causes the current thread to yield
 void sigHandler_ctxSwitch( __CFA_SIGPARMS__ ) {
-        __cfaabi_dbg_debug_do( last_interrupt = (void *)(cxt->uc_mcontext.CFA_REG_IP); )
+        __cfaabi_dbg_debug_do( last_interrupt = (void *)(cxt->uc_mcontext.gregs[CFA_REG_IP]); )
 
         // Check if it is safe to preempt here
         if( !preemption_ready() ) { return; }
-
-        __cfaabi_dbg_print_buffer_decl(" KERNEL: preempting core %p (%p).\n", this_processor, this_thread);
 
         preemption_in_progress = true;                      // Sync flag : prevent recursive calls to the signal handler
@@ -372 +371 @@
 }
 
+// Sigaction wrapper : register an signal handler
+static void __kernel_sigaction( int sig, void (*handler)(__CFA_SIGPARMS__), int flags ) {
+        struct sigaction act;
+
+        act.sa_sigaction = (void (*)(int, siginfo_t *, void *))handler;
+        act.sa_flags = flags;
+
+        if ( sigaction( sig, &act, NULL ) == -1 ) {
+                __cfaabi_dbg_print_buffer_decl(
+                        " __kernel_sigaction( sig:%d, handler:%p, flags:%d ), problem installing signal handler, error(%d) %s.\n",
+                        sig, handler, flags, errno, strerror( errno )
+                );
+                _exit( EXIT_FAILURE );
+        }
+}
+
+// Sigaction wrapper : restore default handler
+static void __kernel_sigdefault( int sig ) {
+        struct sigaction act;
+
+        act.sa_handler = SIG_DFL;
+        act.sa_flags = 0;
+        sigemptyset( &act.sa_mask );
+
+        if ( sigaction( sig, &act, NULL ) == -1 ) {
+                __cfaabi_dbg_print_buffer_decl(
+                        " __kernel_sigdefault( sig:%d ), problem reseting signal handler, error(%d) %s.\n",
+                        sig, errno, strerror( errno )
+                );
+                _exit( EXIT_FAILURE );
+        }
+}
+
+//=============================================================================================
+// Terminating Signals logic
+//=============================================================================================
+
+__cfaabi_dbg_debug_do(
+        static void __kernel_backtrace( int start ) {
+                // skip first N stack frames
+
+                enum { Frames = 50 };
+                void * array[Frames];
+                int size = backtrace( array, Frames );
+                char ** messages = backtrace_symbols( array, size );
+
+                // find executable name
+                *index( messages[0], '(' ) = '\0';
+                #ifdef __USE_STREAM__
+                serr | "Stack back trace for:" | messages[0] | endl;
+                #else
+                fprintf( stderr, "Stack back trace for: %s\n", messages[0]);
+                #endif
+
+                // skip last 2 stack frames after main
+                for ( int i = start; i < size && messages != NULL; i += 1 ) {
+                        char * name = NULL;
+                        char * offset_begin = NULL;
+                        char * offset_end = NULL;
+
+                        for ( char *p = messages[i]; *p; ++p ) {
+                                // find parantheses and +offset
+                                if ( *p == '(' ) {
+                                        name = p;
+                                }
+                                else if ( *p == '+' ) {
+                                        offset_begin = p;
+                                }
+                                else if ( *p == ')' ) {
+                                        offset_end = p;
+                                        break;
+                                }
+                        }
+
+                        // if line contains symbol print it
+                        int frameNo = i - start;
+                        if ( name && offset_begin && offset_end && name < offset_begin ) {
+                                // delimit strings
+                                *name++ = '\0';
+                                *offset_begin++ = '\0';
+                                *offset_end++ = '\0';
+
+                                #ifdef __USE_STREAM__
+                                serr    | "("  | frameNo | ")" | messages[i] | ":"
+                                        | name | "+" | offset_begin | offset_end | endl;
+                                #else
+                                fprintf( stderr, "(%i) %s : %s + %s %s\n", frameNo, messages[i], name, offset_begin, offset_end);
+                                #endif
+                        }
+                        // otherwise, print the whole line
+                        else {
+                                #ifdef __USE_STREAM__
+                                serr | "(" | frameNo | ")" | messages[i] | endl;
+                                #else
+                                fprintf( stderr, "(%i) %s\n", frameNo, messages[i] );
+                                #endif
+                        }
+                }
+
+                free( messages );
+        }
+)
+
+// void sigHandler_segv( __CFA_SIGPARMS__ ) {
+//      __cfaabi_dbg_debug_do(
+//              #ifdef __USE_STREAM__
+//              serr    | "*CFA runtime error* program cfa-cpp terminated with"
+//                      | (sig == SIGSEGV ? "segment fault." : "bus error.")
+//                      | endl;
+//              #else
+//              fprintf( stderr, "*CFA runtime error* program cfa-cpp terminated with %s\n", sig == SIGSEGV ? "segment fault." : "bus error." );
+//              #endif
+
+//              // skip first 2 stack frames
+//              __kernel_backtrace( 1 );
+//      )
+//      exit( EXIT_FAILURE );
+// }
+
+// void sigHandler_abort( __CFA_SIGPARMS__ ) {
+//      // skip first 6 stack frames
+//      __cfaabi_dbg_debug_do( __kernel_backtrace( 6 ); )
+
+//      // reset default signal handler
+//      __kernel_sigdefault( SIGABRT );
+
+//      raise( SIGABRT );
+// }
+
 // Local Variables: //
 // mode: c //