Hi folks,
SMP boot mechanism was a topic in our previous boot architecture meeting[1], and it came up that ePAPR talks about how the problem is solved on PowerPC. You can find it in section 5.5 of the following link[2]:
[1] https://wiki.linaro.org/OfficeofCTO/BootArchitecture/2011-07-07 [2] https://www.power.org/resources/downloads/Power_ePAPR_APPROVED_v1.0.pdf