Changeset 804c0ff

Timestamp:

Jan 15, 2021, 2:23:08 PM (4 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, arm-eh, ast-experimental, enum, forall-pointer-decay, jacob/cs343-translation, master, new-ast-unique-expr, pthread-emulation, qualifiedEnum

Children:

8c43d05

Parents:

b8b0de0c

Message:

Simplified abort handling in the case of concurrent abort.
I used to try to be fancy, now a lock-free algorithm just directly calls libc-abort on ANY subsequent/concurrent calls.

Location:

libcfa/src

Files:

• concurrency/kernel.cfa (modified) (1 diff)
• interpose.cfa (modified) (1 diff)

libcfa/src/concurrency/kernel.cfa

@@ -624 +624 @@
 // Unexpected Terminating logic
 //=============================================================================================
-static __spinlock_t kernel_abort_lock;
-static bool kernel_abort_called = false;
+
+extern "C" {
+        extern void __cfaabi_real_abort(void);
+}
+static volatile bool kernel_abort_called = false;
 
 void * kernel_abort(void) __attribute__ ((__nothrow__)) {
         // abort cannot be recursively entered by the same or different processors because all signal handlers return when
         // the globalAbort flag is true.
-        lock( kernel_abort_lock __cfaabi_dbg_ctx2 );
+        bool first = __atomic_test_and_set( &kernel_abort_called, __ATOMIC_SEQ_CST);
+
+        // first task to abort ?
+        if ( !first ) {
+                // We aren't the first to abort.
+                // I give up, just let C handle it
+                __cfaabi_real_abort();
+        }
 
         // disable interrupts, it no longer makes sense to try to interrupt this processor
         disable_interrupts();
-
-        // first task to abort ?
-        if ( kernel_abort_called ) {                    // not first task to abort ?
-                unlock( kernel_abort_lock );
-
-                sigset_t mask;
-                sigemptyset( &mask );
-                sigaddset( &mask, SIGALRM );            // block SIGALRM signals
-                sigaddset( &mask, SIGUSR1 );            // block SIGALRM signals
-                sigsuspend( &mask );                            // block the processor to prevent further damage during abort
-                _exit( EXIT_FAILURE );                          // if processor unblocks before it is killed, terminate it
-        }
-        else {
-                kernel_abort_called = true;
-                unlock( kernel_abort_lock );
-        }
 
         return __cfaabi_tls.this_thread;

libcfa/src/interpose.cfa

@@ -284 +284 @@
 }
 
+extern "C" {
+        void __cfaabi_real_abort(void) {
+                __cabi_libc.abort();
+        }
+}
+
 void sigHandler_segv( __CFA_SIGPARMS__ ) {
                 if ( sfp->si_addr == 0p ) {