| Message ID | Pine.SOC.4.64.0902051204550.17957@math.ut.ee |
|---|---|
| State | RFC |
| Delegated to: | David Miller |
| Headers | show |
From: Meelis Roos <mroos@linux.ee> Date: Thu, 5 Feb 2009 16:07:14 +0200 (EET) > First, why tell the user to press Stop-A or break at all? Is it because > we can extract information from Break-T, Break-P etc? Otherwise the > panic code could drop to prom itself? You might want to hit SysRQ-something to extract information, remount root read-only, unmount all partitions, force another sync, etc. before dropping to the prom. > I tried the following patch and that did not work - probably because of > the same reason that Break did not work (interrupts off?). Seems the > local_irq_enable() is not enough - but what could help here? Is > prom_halt() the right thing? ... Kad a look of waht Stop-A does, tried > also the second patch... but if it would have worked, Stop-A wouldb > prpbaly also have. > > This patch is of course not even close to merging, it's just a hack to > try it out. What kind of console are you on? For serial consoles, you have to send BREAK twice. For traditional type4/5 serial keyboards, Stop-A should work. For USB keyboard nothing is going to work, sorry. PROM console will also not work for fetching input and breaking into the firmware. -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
> What kind of console are you on? > > For serial consoles, you have to send BREAK twice. I'm on serial console: [ 129.237799] f005de3c: ttyS0 at MMIO 0x1fff8902000 (irq = 2) is a zs (ESCC) [ 129.237925] Console: ttyS0 (SunZilog zs0) [ 129.238289] console [ttyS0] enabled Strange that this time (fresh todays git kernel with no changes) I can use BREAK successfully - and I only need to send it once from minicom (^A F).
From: Meelis Roos <mroos@linux.ee> Date: Fri, 6 Feb 2009 14:38:25 +0200 (EET) > > What kind of console are you on? > > > > For serial consoles, you have to send BREAK twice. > > I'm on serial console: > [ 129.237799] f005de3c: ttyS0 at MMIO 0x1fff8902000 (irq = 2) is a zs (ESCC) > [ 129.237925] Console: ttyS0 (SunZilog zs0) > [ 129.238289] console [ttyS0] enabled > > Strange that this time (fresh todays git kernel with no changes) I can > use BREAK successfully - and I only need to send it once from minicom > (^A F). Strange... I have to send two breaks on hypervisor sun4v consoles. Because the way you send Alt-SYSRQ keycodes on serial consoles is BREAK+sysrq_code, and that's why two breaks are necessary to indicate a real break into the OBP prompt. I suspect it doesn't work for you in that other case because it's at a point before the serial driver has even registered yet. -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
> > I'm on serial console: > > [ 129.237799] f005de3c: ttyS0 at MMIO 0x1fff8902000 (irq = 2) is a zs (ESCC) > > [ 129.237925] Console: ttyS0 (SunZilog zs0) > > [ 129.238289] console [ttyS0] enabled > > > > Strange that this time (fresh todays git kernel with no changes) I can > > use BREAK successfully - and I only need to send it once from minicom > > (^A F). > > Strange... I have to send two breaks on hypervisor sun4v consoles. > > Because the way you send Alt-SYSRQ keycodes on serial consoles > is BREAK+sysrq_code, and that's why two breaks are necessary to > indicate a real break into the OBP prompt. > > I suspect it doesn't work for you in that other case because it's > at a point before the serial driver has even registered yet. I think it was registered... Just tried with fully booted up system (E3500, console on zs serial) and single BREAK was enough to drop to prom ok prompt.
diff --git a/kernel/panic.c b/kernel/panic.c index 2a2ff36..ffe6f2a 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -22,6 +22,9 @@ #include <linux/random.h> #include <linux/kallsyms.h> #include <linux/dmi.h> +#ifdef __sparc__ +#include <asm/oplib.h> +#endif int panic_on_oops; static unsigned long tainted_mask; @@ -120,13 +123,16 @@ NORET_TYPE void panic(const char * fmt, ...) extern int stop_a_enabled; /* Make sure the user can actually press Stop-A (L1-A) */ stop_a_enabled = 1; - printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n"); + printk(KERN_EMERG "Returning to the boot prom\n"); } #endif #if defined(CONFIG_S390) disabled_wait(caller); #endif local_irq_enable(); +#ifdef __sparc__ + prom_halt(); +#endif for (i = 0;;) { touch_softlockup_watchdog(); i += panic_blink(i); And the other one: diff --git a/kernel/panic.c b/kernel/panic.c index 2a2ff36..df46a5c 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -22,6 +22,9 @@ #include <linux/random.h> #include <linux/kallsyms.h> #include <linux/dmi.h> +#ifdef __sparc__ +#include <asm/oplib.h> +#endif int panic_on_oops; static unsigned long tainted_mask; @@ -120,13 +123,19 @@ NORET_TYPE void panic(const char * fmt, ...) extern int stop_a_enabled; /* Make sure the user can actually press Stop-A (L1-A) */ stop_a_enabled = 1; - printk(KERN_EMERG "Press Stop-A (L1-A) to return to the boot prom\n"); + printk(KERN_EMERG "Returning to the boot prom\n"); } #endif #if defined(CONFIG_S390) disabled_wait(caller); #endif local_irq_enable(); +#ifdef __sparc__ + prom_printf("\n"); + flush_user_windows(); + + prom_cmdline(); +#endif for (i = 0;;) { touch_softlockup_watchdog(); i += panic_blink(i);