On 21 Dec 16 14:06, David Miller wrote: > From: Larry Bassel <larry.bassel@xxxxxxxxxx> > Date: Wed, 21 Dec 2016 10:51:33 -0800 > > > On 21 Dec 16 13:07, David Miller wrote: > >> From: Larry Bassel <larry.bassel@xxxxxxxxxx> > >> Date: Wed, 21 Dec 2016 09:12:13 -0800 > >> > >> > Orabug: 24789774 > >> > > >> > The command "shutdown -h -H now" should shut down the system to > >> > OBP, however the machine was incorrectly being powered off instead > >> > (on both LDOM and bare metal). > >> > > >> > The "exit" command to the OBP must be run and then a hard > >> > loop to prevent return to the kernel. > >> > > >> > Signed-off-by: Larry Bassel <larry.bassel@xxxxxxxxxx> > >> > >> On LDOM, once you boot past the early stages of the kernel, OBP is > >> considered volatile and thus unusable. > > > > My code does work on an 4.9.0 LDOM (we get to the ok prompt). So you're saying > > this was a "lucky accident" and there is no "clean" way of getting back to > > the OBP when we are in a LDOM (i.e. all we can do is power off which is > > what the current code does)? > > Yes, for a very long time the firmware/hypervisor engineers told me > exactly this. > > > Unfortunately, the variable "ldom_domaining_enabled" is 1 even when > > we are not in an LDOM (I just double checked this by printing > > the value out as we shut down) and so the current code will power off in > > the bare metal case as well. Is there is a good way of determining that > > we are running on bare metal? > > Even for bare metal the condition holds. As long as we use the interfaces > guarded by ldom_domaining_enabled, the OBP is not reliably available after > early boot. I'm not sure I understand this comment -- are you saying that if we are bare metal (and somehow can know this), one still cannot call into the OBP? There are other calls to the OBP (p1275_cmd_direct) in prom/misc_64.c, some of which are not conditional on ldom_domaining_enabled (which means they would be called even in the LDOM case). If ldom_domaining_enabled is always set, what is the purpose of the "exit" call in prom_halt() at all? It appears that ldc_init() is always called upon kernel initialization (assuming CONFIG_SUN_LDOMS is set) which (barring some error in ldc_init()) permanently sets ldom_domaining_enabled. It appears that CONFIG_SUN_LDOMS is set by defconfig (and I would presume we would want this set so that the same kernel could work in both an LDOM and a bare metal environment). Therefore, I'm looking for some way to know whether I'm really bare metal or not besides checking ldom_domaining_enabled. Should (during kernel initialization) ldc_init() *not* be called when we are bare metal (assuming this can be determined)? My apologies if I'm missing something obvious here. Larry > -- > To unsubscribe from this list: send the line "unsubscribe sparclinux" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
