I finally figured out, why 64bit SGI IP22 kernels are broken (at
least when booted with SGI sash). Looks like sash jumps to an uncached
XPHYS address instead of the KSEG0 address indicated by the ELF start.
This messes up bogomips calculation.
I found an interesting piece of code in head.S:
#if defined(CONFIG_ARC64) || defined(CONFIG_MAPPED_KERNEL)
/* We get launched at a XKPHYS address but the kernel is linked
run at a KSEG0 address, so jump there. */
PTR_LA t0, \@f
Enabling this for (CONFIG_SGI_IP22 && CONFIG_64BIT) fixes the boot problem.
It's not big deal to add this, but I'm wondering why we not just always
use this macro ? What platforms do it break with it ?
Crap can work. Given enough thrust pigs will fly, but it's not necessary a
good idea. [ RFC1925, 2.3 ]