On Wed, 2006-09-13 at 01:13, Jack Steiner wrote: > > Hi, > > Below is the IA64 kexec/kdump patch against 2.6.18-rc5. > > > ... > > 3. put AP to a loop of hint.pause instead of call pal_halt_light. > > diff -Nraup linux-2.6.18-rc5/arch/ia64/kernel/smp.c linux-2.6.18-rc5-kdump/arch/ia64/kernel/smp.c > > --- linux-2.6.18-rc5/arch/ia64/kernel/smp.c 2006-06-18 09:49:35.000000000 +0800 > > +++ linux-2.6.18-rc5-kdump/arch/ia64/kernel/smp.c 2006-08-30 10:36:01.000000000 +0800 > ... > > +void > > +kexec_stop_this_cpu (void *func) > > +{ > > + unsigned long pta, impl_va_bits, pal_base; > > + > > + /* > > + * Remove this CPU by putting it into fake SAL rendezvous > > + */ > > + cpu_clear(smp_processor_id(), cpu_online_map); > > + max_xtp(); > > + ia64_eoi(); > > + > > + /* Disable VHPT */ > > + impl_va_bits = ffz(~(local_cpu_data->unimpl_va_mask | (7UL << 61))); > > + pta = POW2(61) - POW2(vmlpt_bits); > > + ia64_set_pta(pta | (0 << 8) | (vmlpt_bits << 2) | 0); > > + > > + local_irq_disable(); > > + pal_base = __get_cpu_var(ia64_mca_pal_base); > > + kexec_fake_sal_rendez(func, ap_wakeup_vector, pal_base); > > +} > > +#endif > > What was the reason for introducing the kexec_fake_sal_rendez() function instead of > actually returning to the real SAL slave loop. The HOTPLUG_CPU code in play_dead() > in arch/ia64/kernel/process.c is very similar to what is needed. > the fake_sal_rendez code is from Aziz to be used at time of kexec -l if CONFIG_HOTPLUG_CPU is not defined. They are not executed at the time of crash dump. > > I'm sure the problem is platform specific, but on the SN platform, the other cpus must be > sent back to the real SAL slave loops. Otherwise, targeting of IO interrupts > will not work correctly in the new kexec'd kernel. > > IO interrupts are distributed across cpus that are not in the SAL slave loop. If > cpus are idled in the OS instead of SAL, interrrupts are incorrected targeted > to cpus that cannot respond. > > At the time of crash, neither fake nor real SAL rendez state are entered. I just put all the other cpus into cpu_relax loop to simplify the code. Does it work on SN2 if you call ia64_jump_to_sal at kdump_cpu_freeze? Thanks Zou Nan hai > > -- jack - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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