On Thu, Oct 26, 2017 at 10:32:42PM +1100, Jonathan Gray wrote:
> What specifically? Skip if_downall() if rebooting from ddb?
> That could perhaps even be done for RB_NOSYNC.
I thought of someting like a big hammer. Skip everything except
the final call in boot() that causes the machine to reset. The
command is only reachable form ddb and useful if nothing else can
reboot the machine.
Here is an example implementation for amd64.
bluhm
Index: arch/amd64/amd64/machdep.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/arch/amd64/amd64/machdep.c,v
retrieving revision 1.234
diff -u -p -r1.234 machdep.c
--- arch/amd64/amd64/machdep.c 23 Oct 2017 15:41:29 -0000 1.234
+++ arch/amd64/amd64/machdep.c 26 Oct 2017 11:43:55 -0000
@@ -713,6 +713,9 @@ struct pcb dumppcb;
__dead void
boot(int howto)
{
+ if ((howto & RB_RESET) != 0)
+ goto reset;
+
if ((howto & RB_POWERDOWN) != 0)
lid_action = 0;
@@ -770,6 +773,7 @@ haltsys:
printf("rebooting...\n");
if (cpureset_delay > 0)
delay(cpureset_delay * 1000);
+reset:
cpu_reset();
for (;;)
continue;
Index: sys/reboot.h
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/sys/reboot.h,v
retrieving revision 1.17
diff -u -p -r1.17 reboot.h
--- sys/reboot.h 11 Jul 2014 14:36:44 -0000 1.17
+++ sys/reboot.h 26 Oct 2017 11:41:56 -0000
@@ -56,6 +56,7 @@
#define RB_POWERDOWN 0x1000 /* attempt to power down machine */
#define RB_SERCONS 0x2000 /* use serial console if available */
#define RB_USERREQ 0x4000 /* boot() called at user request (e.g.
ddb) */
+#define RB_RESET 0x8000 /* do not try to cleanup, only for ddb
*/
/*
* Constants for converting boot-style device number to type,
