Date: Sun, 28 Apr 2019 22:18:52 +0000 From: bugzilla-noreply@freebsd.org To: ppc@FreeBSD.org Subject: [Bug 235060] [boot] FreeBSD 12.0 Release DVD and CD will not boot on PowerMac G5 Quad Message-ID: <bug-235060-21-a2xJgWOwzm@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-235060-21@https.bugs.freebsd.org/bugzilla/> References: <bug-235060-21@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D235060 --- Comment #15 from Mark Millard <marklmi26-fbsd@yahoo.com> --- (In reply to Dennis Clarke from comment #13) First my overall point, then what leads to it . . . Overall point: I'm not sure testing anything with head -r334498 involved is worth testing for multi-socket or for multi-core unless the code has been changed to address the resultant slb-miss issue on the non-bsp cpu(s) in some way. What leads to that: I'll note that anything form just svn at or after head -r334498 (or later in svn that is derived from such) has known boot problems on at least some G5 PowerMacs that have multiple sockets or cores. The issue in question is an unhandled slb miss in the code during a (non-bsp) cpu's startup code when it executes: sp =3D pcpup->pc_curpcb->pcb_sp It is the pc_curpcb based dereference that can end up with a slb miss before things are set up sufficiently for that processor to correctly handle such misses. head -r334498 changed the address ranges used for powerpc64 and indirectly resulted in this being possible on some old G5 PowerMacs. (32-bit powerpc FreeBSD boots of old G5's are a separate issue.) I'm not here making any claims about there not being other boot problems sometimes involved. But, to my knowledge, all builds based on just checked-in source code that has -r334498 involved has multi-socket/multi-core boot problems. (They can be intermittent, sometimes hanging-up and other times not, depending on slb content at the time.) Bugzilla 233863 that you reference has a fair amount of accumulated information, but not limited to fixing what -r334498 exposes about the way things historically worked, so it is a bit of a mess to go through for the slb issue. --=20 You are receiving this mail because: You are the assignee for the bug.=
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