# This patch changes UML's internal signal handling so that it is not dependent
# on the host delivering signals in a particular order, i.e. in numeric order.
# This was prompted by 2.6 changes which involve signals being queued onto
# two queues, a process queue and a task queue.  Signals are picked off one,
# and then off the other, and when there are signals on both, they may be
# delivered in the opposite order that they were on 2.4 hosts.  There was
# an implicit assumption in UML that SIGUSR1 would be delivered before anything
# else, which was true for a while because its signal number is lower than any
# of the others that it cares about.
Index: um/arch/um/kernel/tt/exec_kern.c
===================================================================
--- um.orig/arch/um/kernel/tt/exec_kern.c	2004-08-06 16:25:45.000000000 -0400
+++ um/arch/um/kernel/tt/exec_kern.c	2004-08-06 16:29:46.000000000 -0400
@@ -14,6 +14,7 @@
 #include "kern_util.h"
 #include "irq_user.h"
 #include "time_user.h"
+#include "signal_user.h"
 #include "mem_user.h"
 #include "os.h"
 #include "tlb.h"
@@ -54,7 +55,9 @@
 	current->thread.request.u.exec.pid = new_pid;
 	unprotect_stack((unsigned long) current_thread);
 	os_usr1_process(os_getpid());
+	change_sig(SIGUSR1, 1);
 
+	change_sig(SIGUSR1, 0);
 	enable_timer();
 	free_page(stack);
 	protect_memory(uml_reserved, high_physmem - uml_reserved, 1, 1, 0, 1);
Index: um/arch/um/kernel/tt/process_kern.c
===================================================================
--- um.orig/arch/um/kernel/tt/process_kern.c	2004-08-06 16:25:45.000000000 -0400
+++ um/arch/um/kernel/tt/process_kern.c	2004-08-06 16:29:46.000000000 -0400
@@ -161,6 +161,12 @@
 	local_irq_enable();
 	if(!run_kernel_thread(fn, arg, &current->thread.exec_buf))
 		do_exit(0);
+	
+	/* XXX No set_user_mode here because a newly execed process will
+	 * immediately segfault on its non-existent IP, coming straight back
+	 * to the signal handler, which will call set_user_mode on its way
+	 * out.  This should probably change since it's confusing.
+	 */
 }
 
 static int new_thread_proc(void *stack)
@@ -183,6 +189,7 @@
 	local_irq_disable();
 	init_new_thread_stack(stack, new_thread_handler);
 	os_usr1_process(os_getpid());
+	change_sig(SIGUSR1, 1);
 	return(0);
 }
 
@@ -226,6 +233,7 @@
 	init_new_thread_stack(stack, finish_fork_handler);
 
 	os_usr1_process(os_getpid());
+	change_sig(SIGUSR1, 1);
 	return(0);
 }
 
@@ -278,6 +286,13 @@
 	current->thread.request.op = OP_FORK;
 	current->thread.request.u.fork.pid = new_pid;
 	os_usr1_process(os_getpid());
+
+	/* Enable the signal and then disable it to ensure that it is handled
+	 * here, and nowhere else.
+	 */
+	change_sig(SIGUSR1, 1);
+
+	change_sig(SIGUSR1, 0);
 	err = 0;
  out:
 	return(err);
@@ -287,12 +302,14 @@
 {
 	current->thread.request.op = OP_REBOOT;
 	os_usr1_process(os_getpid());
+	change_sig(SIGUSR1, 1);
 }
 
 void halt_tt(void)
 {
 	current->thread.request.op = OP_HALT;
 	os_usr1_process(os_getpid());
+	change_sig(SIGUSR1, 1);
 }
 
 void kill_off_processes_tt(void)
@@ -319,6 +336,9 @@
 		current->thread.request.u.cb.proc = proc;
 		current->thread.request.u.cb.arg = arg;
 		os_usr1_process(os_getpid());
+		change_sig(SIGUSR1, 1);
+
+		change_sig(SIGUSR1, 0);
 	}
 }
 
Index: um/arch/um/kernel/tt/trap_user.c
===================================================================
--- um.orig/arch/um/kernel/tt/trap_user.c	2004-08-06 16:25:45.000000000 -0400
+++ um/arch/um/kernel/tt/trap_user.c	2004-08-06 16:29:46.000000000 -0400
@@ -37,7 +37,6 @@
 	if(sig != SIGUSR2) 
 		r->syscall = -1;
 
-	change_sig(SIGUSR1, 1);
 	info = &sig_info[sig];
 	if(!info->is_irq) unblock_signals();
 
@@ -46,7 +45,6 @@
 	if(is_user){
 		interrupt_end();
 		block_signals();
-		change_sig(SIGUSR1, 0);
 		set_user_mode(NULL);
 	}
 	*r = save_regs;