On Tue, 6 Oct 2026, Bin Meng wrote:
The BookE PIR registration reuses the classic PowerPC 604 write
callback, which writes SPR 1023 and masks the value to four bits.
BookE PIR is SPR 286; on e500, SPR 1023 is SVR, so a PIR write can
corrupt SVR while leaving PIR unchanged.
The e500v1/e500v2 manual defines PIR as read-only. The e500mc, e5500
and e6500 manuals allow hypervisor software to write PIR after reset.
Reject writes on e500v1/e500v2 and use the generic 32-bit SPR write
callback on the other three cores to update the correct register
without the four-bit restriction.
Reference:
- E500CORERM (Rev.1), section 2.5.2
https://www.nxp.com/docs/en/reference-manual/E500CORERM.pdf
- E500MCRM (Rev.3), section 2.9.7
https://www.nxp.com/docs/en/reference-manual/E500MCRM.pdf
- E5500RM (Rev.4), section 2.9.7
https://www.nxp.com/webapp/Download?colCode=E5500RM
- E6500RM (Rev.0), section 2.9.8
https://www.nxp.com/docs/en/reference-manual/E6500RM.pdf
I'm not sure about URLs in commit messages which might go stale. I think
the reference to title and section is enough without the URL but whatever
others prefer is fine with me too.
Regards,
BALATON Zoltan
