Date: Sun, 27 Sep 2020 13:44:29 -0700 From: Mark Millard <marklmi@yahoo.com> To: Brandon Bergren <bdragon@FreeBSD.org> Cc: FreeBSD PowerPC ML <freebsd-ppc@freebsd.org> Subject: Re: head -r365932 on PowerMac G5 (2 dual-core sockets): Crashes before login prompt if powerd is enabled in /etc/rc.conf Message-ID: <7DC3081D-8B19-476A-990F-4DFD7003672C@yahoo.com> In-Reply-To: <88052e3f-4b79-45ca-8ebb-9fc19cbc558b@www.fastmail.com> References: <52783D16-5DCA-45BC-9238-2518326454A1@yahoo.com> <6E99EE39-D2B8-415A-A5BF-823C0F0C22D6@yahoo.com> <cd9d2b72-219f-4550-a437-4ac3aa1da66d@www.fastmail.com> <AF27169A-00FC-4984-83C2-307EA885D7A1@yahoo.com> <11fe573a-24c3-47be-95ed-c601ec54f168@www.fastmail.com> <E23CF7F6-B69C-44C7-B356-4AB65E011268@yahoo.com> <B4D16405-1B0C-4500-866F-75F32FED235A@yahoo.com> <92f57afb-33cb-4d38-be17-4b8c81cb9c89@www.fastmail.com> <D6DC1C60-E50D-4A12-9F3B-6CEBA6A76748@yahoo.com> <6a0ade9d-26f2-4448-b066-0b06ed3ba5ef@www.fastmail.com> <9D4314E7-92C9-4BDD-B023-8C9BC3DCCAB0@yahoo.com> <E1EEDF91-42B1-4319-9513-7DE6FDE6E5F3@yahoo.com> <F1808C34-3C1A-44DC-BB23-2F0959AC64F5@yahoo.com> <db3de197-eb27-40ef-89ac-433b7fa72fe4@www.fastmail.com> <5E79BB07-D54B-4A8E-B592-F480211D0B92@yahoo.com> <88052e3f-4b79-45ca-8ebb-9fc19cbc558b@www.fastmail.com>
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On 2020-Sep-23, at 09:09, Brandon Bergren <bdragon@FreeBSD.org> wrote: > On Wed, Sep 23, 2020, at 3:58 AM, Mark Millard wrote: >> On 2020-Sep-23, at 00:04, Brandon Bergren <bdragon at FreeBSD.org> = wrote: >>=20 >>> . . . >>>=20 >>> Are you making sure to use the "dev /memory@0 100000 1000 do-unmap" = trick on 4.8.7f1 devices? >>=20 >> I know nothing about that and have never had to do such a thing >> historically. I've never had to identify "4.8.7f1 devices". >=20 > There is a bug in some versions of the PowerMac BootROM where a memory = page at 0x100000 would remain mapped without being properly listed in = the mmu properties (likely due to the way Open Firmware was initialized) = that breaks bootloaders that touch that page. >=20 > It is known to be a thing on at least 4.8.7f1 BootROM, but may also = affect other versions. You can see the BootROM version on the = OpenFirmware screen when the machine turns on. >=20 > On affected devices, the bug can be permanently repaired using nvedit = to execute the workaround automatically, or it can be typed in by hand = every time. >=20 > This is described on https://wiki.freebsd.org/powerpc In case it is related: in ofwfdt_fixups my environment uses: offset =3D fdt_path_offset(fdtp, "/rtas"); if (offset > 0) { . . . } else { #if 0 // Without the /memory0/available information the example // MPC750 iMac G3 PowerMac4,1 crashes shortly after booting // --from trashed memory contents from use of RAM that was // not excluded when available was being deleted. // // My guess is that openfirmware may also report to // avoid address ranges for which other things in the // environment are the cause, not just openfirmware's // internal memory use. // // So do not do the following . . . =20 /* * Remove /memory/available properties, which reflect = long-gone * OF state. Note that this doesn't work if we need RTAS = still, * since that's part of the firmware. */ offset =3D fdt_path_offset(fdtp, "/memory@0"); if (offset<=3D0) offset=3D fdt_path_offset(fdtp, = "/memory@0,0"); // G5's if (offset > 0) fdt_delprop(fdtp, offset, "available"); #endif } The // G5's line is also mine. =3D=3D=3D Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar)
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