um: add earlyprintk support

[pandora-kernel.git] / arch / um / os-Linux / util.c

diff --git a/arch/um/os-Linux/util.c b/arch/um/os-Linux/util.c
index 6ea7797..5803b18 100644 (file)
--- a/arch/um/os-Linux/util.c
+++ b/arch/um/os-Linux/util.c
@@ -5,6 +5,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <unistd.h>
 #include <errno.h>
 #include <signal.h>
 #include <string.h>
@@ -75,6 +76,26 @@ void setup_hostinfo(char *buf, int len)
                 host.release, host.version, host.machine);
 }
 
+/*
+ * We cannot use glibc's abort(). It makes use of tgkill() which
+ * has no effect within UML's kernel threads.
+ * After that glibc would execute an invalid instruction to kill
+ * the calling process and UML crashes with SIGSEGV.
+ */
+static inline void __attribute__ ((noreturn)) uml_abort(void)
+{
+       sigset_t sig;
+
+       fflush(NULL);
+
+       if (!sigemptyset(&sig) && !sigaddset(&sig, SIGABRT))
+               sigprocmask(SIG_UNBLOCK, &sig, 0);
+
+       for (;;)
+               if (kill(getpid(), SIGABRT) < 0)
+                       exit(127);
+}
+
 void os_dump_core(void)
 {
        int pid;
@@ -116,5 +137,10 @@ void os_dump_core(void)
        while ((pid = waitpid(-1, NULL, WNOHANG | __WALL)) > 0)
                os_kill_ptraced_process(pid, 0);
 
-       abort();
+       uml_abort();
+}
+
+void um_early_printk(const char *s, unsigned int n)
+{
+       printf("%.*s", n, s);
 }