diff --git a/pc-bios/s390-ccw/s390-ccw.h b/pc-bios/s390-ccw/s390-ccw.h
index c977a52b50..de3d1f0d5a 100644
--- a/pc-bios/s390-ccw/s390-ccw.h
+++ b/pc-bios/s390-ccw/s390-ccw.h
@@ -43,6 +43,7 @@ typedef unsigned long long u64;
#include "iplb.h"
/* start.s */
+extern char _start[];
void disabled_wait(void) __attribute__ ((__noreturn__));
void consume_sclp_int(void);
void consume_io_int(void);
@@ -88,6 +89,11 @@ __attribute__ ((__noreturn__))
static inline void panic(const char *string)
{
sclp_print(string);
+ if (load_next_iplb()) {
+ sclp_print("\nTrying next boot device...");
+ jump_to_IPL_code((long)_start);
+ }
+
disabled_wait();
}
Honestly, I am unsure whether this is a really cool idea or a very
ugly hack ... but I think I tend towards the latter, sorry. Jumping
back to the startup code might cause various problem, e.g.
pre-initialized variables don't get their values reset, causing
different behavior when the s390-ccw bios runs a function a second
time this way. Thus this sounds very fragile. Could we please try to
get things cleaned up correctly, so that functions return with error
codes instead of panicking when we can continue with another boot
device? Even if its more work right now, I think this will be much
more maintainable in the future.
Thomas
Thanks Thomas, I appreciate your insight. Your hesitation is perfectly
understandable as well. My initial design was like you suggest, where
the functions return instead of panic, but the issue I ran into is that
netboot uses a separate image, which we jump in to at the start of IPL
from a network device (see zipl_load() in pc-bios/s390-ccw/bootmap.c).
I wasn't able to come up with a simple way to return to the main BIOS
code if a netboot fails other than by jumping back. So, it seems to me
that netboot kind of throws a monkeywrench into the basic idea of
reworking the panics into returns.
I'm open to suggestions on a better way to recover from a failed
netboot, and it's certainly possible I've overlooked something, but as
far as I can tell a jump is necessary in that particular case at least.
Netboot could perhaps be handled as a special case where the jump back
is permitted whereas other device types return, but I don't think that
actually solves the main issue.
What are your thoughts on this?
Thanks,
Jared Rossi
