Merge pull request #229 from LudwigOrtmann/native_fix_syscall_segfault

fix some segfault sources in native

cpu/native/irq_cpu.c

@@ -41,6 +41,7 @@ extern volatile tcb_t *active_thread;
 
 volatile unsigned int _native_saved_eip;
 ucontext_t *_native_cur_ctx, *_native_isr_ctx;
+int *process_heap_address;
 
 static int pipefd[2];
 
@@ -164,20 +165,8 @@ unsigned disableIRQ(void)
     prev_state = native_interrupts_enabled;
     native_interrupts_enabled = 0;
 
-    // XXX: does this make sense?
-    if ((_native_sigpend > 0) && (_native_in_isr == 0)) {
-        DEBUG("\n\n\t\treturn from syscall, calling native_irq_handler\n\n");
-        _native_in_syscall = 0;
-        DEBUG("disableIRQ: calling swapcontext()\n");
-        DEBUG("disableIRQ: _native_cur_ctx == %p, _native_isr_ctx == %p\n", _native_cur_ctx, _native_isr_ctx);
-        makecontext(&native_isr_context, native_irq_handler, 0);
-        swapcontext(_native_cur_ctx, _native_isr_ctx);
-    }
-    else {
-        _native_in_syscall = 0;
-    }
-
     DEBUG("disableIRQ(): return\n");
+    _native_in_syscall = 0;
 
     return prev_state;
 }
@@ -206,6 +195,7 @@ unsigned enableIRQ(void)
     //print_sigmasks();
     //native_print_signals();
     if ((_native_sigpend > 0) && (_native_in_isr == 0)) {
+        _native_cur_ctx = (ucontext_t *)active_thread->sp;
         DEBUG("\n\n\t\treturn from syscall, calling native_irq_handler\n\n");
         _native_in_syscall = 0;
         DEBUG("enableIRQ: calling swapcontext()\n");
@@ -317,23 +307,23 @@ void native_isr_entry(int sig, siginfo_t *info, void *context)
     (void) info; /* unused at the moment */
     DEBUG("\n\n\t\tnative_isr_entry\n\n");
 
-    if (native_interrupts_enabled == 0) {
-        errx(1, "interrupts are off, but I caught a signal.");
-    }
-
     /* save the signal */
     if (write(pipefd[1], &sig, sizeof(int)) == -1) {
         err(1, "native_isr_entry(): write()");
     }
-
     _native_sigpend++;
-    /* indicate irs status */
 
     makecontext(&native_isr_context, native_irq_handler, 0);
     _native_cur_ctx = (ucontext_t *)active_thread->sp;
 
+    /* XXX: Workaround safety check - whenever this happens it really
+     * indicates a bug in disableIRQ */
+    if (native_interrupts_enabled == 0) {
+        warnx("interrupts are off, but I caught a signal.");
+        return;
+    }
+
     if (_native_in_syscall == 0) {
-        _native_in_isr = 1;
         DEBUG("\n\n\t\treturn to _native_sig_leave_tramp\n\n");
 #ifdef __MACH__
         _native_saved_eip = ((ucontext_t *)context)->uc_mcontext->__ss.__eip;
@@ -342,8 +332,18 @@ void native_isr_entry(int sig, siginfo_t *info, void *context)
         _native_saved_eip = ((struct sigcontext *)context)->sc_eip;
         ((struct sigcontext *)context)->sc_eip = (unsigned int)&_native_sig_leave_tramp;
 #else
-        _native_saved_eip = ((ucontext_t *)context)->uc_mcontext.gregs[REG_EIP];
-        ((ucontext_t *)context)->uc_mcontext.gregs[REG_EIP] = (unsigned int)&_native_sig_leave_tramp;
+        if (
+                ((void*)(((ucontext_t *)context)->uc_mcontext.gregs[REG_EIP]))
+                > ((void*)process_heap_address)
+           ) {
+            DEBUG("\nEIP:\t%p\nHEAP:\t%p\nnot switching\n\n", (void*)((ucontext_t *)context)->uc_mcontext.gregs[REG_EIP], (void*)process_heap_address);
+        }
+        else {
+            _native_in_isr = 1;
+            warnx("\nEIP:\t%p\nHEAP:\t%p\ngo switching\n\n", (void*)((ucontext_t *)context)->uc_mcontext.gregs[REG_EIP], (void*)process_heap_address);
+            _native_saved_eip = ((ucontext_t *)context)->uc_mcontext.gregs[REG_EIP];
+            ((ucontext_t *)context)->uc_mcontext.gregs[REG_EIP] = (unsigned int)&_native_sig_leave_tramp;
+        }
 #endif
         // TODO: change sigmask?
     }
@@ -429,6 +429,11 @@ void native_interrupt_init(void)
     struct sigaction sa;
     DEBUG("XXX: native_interrupt_init()\n");
 
+   process_heap_address = malloc(sizeof(int));
+    if (process_heap_address == NULL) {
+        err(EXIT_FAILURE, "native_interrupt_init: malloc");
+    }
+
     native_interrupts_enabled = 1;
     _native_sigpend = 0;
 

cpu/native/native_cpu.c

@@ -88,14 +88,19 @@ char *thread_stack_init(void (*task_func)(void), void *stack_start, int stacksiz
 void cpu_switch_context_exit(void)
 {
     ucontext_t *ctx;
+    extern int native_interrupts_enabled;
 
     DEBUG("XXX: cpu_switch_context_exit()\n");
-    //active_thread = sched_threads[0];
-    sched_run();
+    if ((sched_context_switch_request == 1) || (active_thread == NULL)) {
+        sched_run();
+    }
 
     DEBUG("XXX: cpu_switch_context_exit(): calling setcontext(%s)\n\n", active_thread->name);
     ctx = (ucontext_t *)(active_thread->sp);
-    eINT(); // XXX: workaround for bug (?) in sched_task_exit
+
+    /* the next context will have interrupts enabled due to ucontext */
+    DEBUG("XXX: cpu_switch_context_exit: native_interrupts_enabled = 1;\n");
+    native_interrupts_enabled = 1;
 
     if (setcontext(ctx) == -1) {
         err(1, "cpu_switch_context_exit(): setcontext():");

cpu/native/rtc/posix-rtc.c

@@ -24,6 +24,7 @@
 #include "debug.h"
 
 #include "rtc.h"
+#include "cpu.h"
 
 static int native_rtc_enabled;
 
@@ -58,10 +59,12 @@ void rtc_get_localtime(struct tm *localt)
     time_t t;
 
     if (native_rtc_enabled == 1) {
+        _native_in_syscall++;
         t = time(NULL);
 
         if (localtime_r(&t, localt) == NULL) {
             err(1, "rtc_get_localtime: localtime_r");
         }
+        _native_in_syscall--;
     }
 }