Can you add a short comment in cmain why it's needed? It should mention 32-bit address truncation. The story in the commit message, on the other hand, is way too long. It needs to be summarized with a link to full story.
Le lun. 7 oct. 2024, 21:19, Leo Sandoval <lsand...@redhat.com> a écrit : > From: Paulo Flabiano Smorigo <pfsmor...@br.ibm.com> > > Disable GRUB Video Support from IBM Power Machines. This patch fixes what > is describe above and should fix > https://bugzilla.redhat.com/show_bug.cgi?id=973205. > C&P <https://bugzilla.redhat.com/show_bug.cgi?id=973205.C&P> the bz > problem's description: > > Grub crashes if it tries to run in video mode. > > I'm currently testing with grub rpm from f18 in a lpar inside a Power 7R2 > machine using a matrox video card attached. > > To reproduce you need to redirect the console to the video output. > > This will happens: > > IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM > IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM > IBM IBM IBM IBM IBM IBM STARTING SOFTWARE IBM IBM IBM IBM IBM IBM > IBM IBM IBM IBM IBM IBM PLEASE WAIT... IBM IBM IBM IBM IBM IBM > IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM > IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM > IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM > IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM > IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM > IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM > IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM > IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM > IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM > IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM > IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM > IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM IBM > > Welcome to GRUB > > DEFAULT CATCH!, exception-handler=fff00300 > at %SRR0: 000000000020ac80 %SRR1: 0000000000003002 > Open Firmware exception handler entered from non-OF code > > Client's Fix Pt Regs: > 00 0000000000780c38 0000000001adfc40 0000000000000000 0000000018000000 > 04 0000000000780850 000000000004afff 00000000001d2bb0 0000000000000000 > 08 0000000018000000 fffffffffffb5000 000000001804b000 0000000001adfc50 > 0c 0000000000000008 0000000000000000 0000000000800050 0000000002000066 > 10 0000000002000065 0000000002000070 000000000200006e 0000000002000067 > 14 0000000002000063 0000000000000001 00000000001a0000 0000000000000002 > 18 0000000000000002 0000000000000000 0000000000780dce 00000000ffff8080 > 1c 0000000000000067 00000000001d3de0 00000000001d2b30 0000000000000002 > Special Regs: > %IV: 00000300 %CR: 22002084 %XER: 20000000 %DSISR: 42000000 > %SRR0: 000000000020ac80 %SRR1: 0000000000003002 > %LR: 0000000000006584 %CTR: 000000000004b000 > %DAR: 000000001804afff > Virtual PID = 0 > ok > 0 > > > In Power, GRUB has video support and works fine with PowerMAC. > > Theorically it should works with IBM machines as well but, using a Matrox > videocard and grub.cfg with the video option enabled, GRUB crashes as we > saw above. > > Using GRUB debug we saw that the crash happens because GRUB tries to > access the video card address: > > video/ieee1275.c:236: IEEE1275: keeping current mode 640x480 > video/ieee1275.c:266: IEEE1275: initialising FB @ 0x18000000 640x480x8 > > GRUB gets the address from the display card node from openfirmware. The > property is called "address": > > 0 > dev /pci@80000002000000d/pci@0/display@0 ok > 0 > .properties > ibm,loc-code U78AB.001.WZSHS9P-P1-C7-T1 > vendor-id 0000102b > device-id 00002527 > revision-id 00000001 > class-code 00030000 > interrupts 00000001 > min-grant 00000010 > max-latency 00000020 > subsystem-vendor-id 0000102b > subsystem-id 00002300 > devsel-speed 00000001 > fast-back-to-back > built-in > name display > compatible MTRX,G550 > pci102b,2527 > pciclass,030000 > display > reg 00990000 00000000 00000000 00000000 00000000 > 02990030 00000000 00000000 00000000 00010000 > 02990010 00000000 00000000 00000000 04000000 > 02990014 00000000 00000000 00000000 00800000 > 02990018 00000000 00000000 00000000 00800000 > fcode-rom-offset 00009000 > device_type display > character-set ISO8859-1 > iso6429-1983-colors > power-consumption 00000000 00000000 007270e0 007270e0 00000000 > 00000000 007b98a0 007b98a0 > ibm,fw-revision-level 00000100 > assigned-addresses 82990010 00000000 f8000000 00000000 04000000 > 82990014 00000000 f7000000 00000000 00800000 > 82990018 00000000 f7800000 00000000 00800000 > 82990030 00000000 f6fe0000 00000000 00020000 > address 18000000 17000000 > width 00000280 > height 000001e0 > depth 00000008 > linebytes 00000280 > bios release 01000000 > > ok > 0 > > > Kleber Sacilotto sent me the address that linux returned from the probe: > > 99:00.0 VGA compatible controller: Matrox Electronics Systems Ltd. > Millennium G550 (rev 01) (prog-if 00 [VGA controller]) > Subsystem: Matrox Electronics Systems Ltd. Millennium G550 LP PCIE > Control: I/O- Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- > ParErr- Stepping- SERR- FastB2B- DisINTx- > Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- > <TAbort- <MAbort- >SERR- <PERR- INTx- > Interrupt: pin A routed to IRQ 0 > Region 0: Memory at 3da318000000 (32-bit, prefetchable) [size=64M] > Region 1: Memory at 3da317000000 (32-bit, non-prefetchable) > [size=8M] > Region 2: Memory at 3da317800000 (32-bit, non-prefetchable) > [size=8M] > Expansion ROM at 3da316fe0000 [disabled] [size=128K] > Capabilities: [dc] Power Management version 2 > Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA > PME(D0-,D1-,D2-,D3hot-,D3cold-) > Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME- > Capabilities: [f0] AGP version 2.0 > Status: RQ=32 Iso- ArqSz=0 Cal=0 SBA+ ITACoh- GART64- > HTrans- 64bit- FW- AGP3- Rate=x1,x2 > Command: RQ=1 ArqSz=0 Cal=0 SBA- AGP- GART64- 64bit- FW- > Rate=<none> > Kernel driver in use: matroxfb > > The address is 64bit and display property in openfirmware was cut because > it's "encode-int" (32bit): > > From linux: > Region 0: Memory at 3da318000000 (32-bit, prefetchable) [size=64M] > Region 1: Memory at 3da317000000 (32-bit, non-prefetchable) [size=8M] > > From openfirmware: > address 18000000 17000000 > > David Randall confirmed that the linux address is right after getting the > full address using other properties from the videocard node. > > We talked with Colleen about the address property from the Matrox card and > she said that the node is generated from a FCode that is inside the card, > owned by Matrox. > > Openfirmware works in 32bit mode so GRUB for Power is hotwired in 32bit, > even for 64bit machines. > > David taught us how to get the full address but, as GRUB is build in 32bit > and the value is 64 we need to implement an asm helper in order to access > it. > > Marcelo Cerri, from ltc security team, helped me writing an asm help to > access the address but we still didn't managed to make it work. > > We will continue to work in the asm to see if we can access the address. > > Besides that, I'm going to implement an address validation in GRUB before > it tries to access the address. If the address is invalid it will return an > exception and will continue to run in text mode. > > Signed-off-by: Paulo Flabiano Smorigo <pfsmor...@br.ibm.com> > Signed-off-by: Robbie Harwood <rharw...@redhat.com> > --- > grub-core/kern/ieee1275/cmain.c | 5 ++++- > grub-core/video/ieee1275.c | 9 ++++++--- > include/grub/ieee1275/ieee1275.h | 2 ++ > 3 files changed, 12 insertions(+), 4 deletions(-) > > diff --git a/grub-core/kern/ieee1275/cmain.c > b/grub-core/kern/ieee1275/cmain.c > index e74de3248..810a089a9 100644 > --- a/grub-core/kern/ieee1275/cmain.c > +++ b/grub-core/kern/ieee1275/cmain.c > @@ -89,7 +89,10 @@ grub_ieee1275_find_options (void) > } > > if (rc >= 0 && grub_strncmp (tmp, "IBM", 3) == 0) > - grub_ieee1275_set_flag > (GRUB_IEEE1275_FLAG_NO_TREE_SCANNING_FOR_DISKS); > + { > + grub_ieee1275_set_flag > (GRUB_IEEE1275_FLAG_NO_TREE_SCANNING_FOR_DISKS); > + grub_ieee1275_set_flag (GRUB_IEEE1275_FLAG_DISABLE_VIDEO_SUPPORT); > + } > > /* Old Macs have no key repeat, newer ones have fully working one. > The ones inbetween when repeated key generates an escaoe sequence > diff --git a/grub-core/video/ieee1275.c b/grub-core/video/ieee1275.c > index ca3d3c3b2..5592e4bb7 100644 > --- a/grub-core/video/ieee1275.c > +++ b/grub-core/video/ieee1275.c > @@ -351,9 +351,12 @@ static struct grub_video_adapter > grub_video_ieee1275_adapter = > > GRUB_MOD_INIT(ieee1275_fb) > { > - find_display (); > - if (display) > - grub_video_register (&grub_video_ieee1275_adapter); > + if (! grub_ieee1275_test_flag > (GRUB_IEEE1275_FLAG_DISABLE_VIDEO_SUPPORT)) > + { > + find_display (); > + if (display) > + grub_video_register (&grub_video_ieee1275_adapter); > + } > } > > GRUB_MOD_FINI(ieee1275_fb) > diff --git a/include/grub/ieee1275/ieee1275.h > b/include/grub/ieee1275/ieee1275.h > index 4f6e6aaa0..db0ec5f4c 100644 > --- a/include/grub/ieee1275/ieee1275.h > +++ b/include/grub/ieee1275/ieee1275.h > @@ -145,6 +145,8 @@ enum grub_ieee1275_flag > GRUB_IEEE1275_FLAG_POWER_VM, > > GRUB_IEEE1275_FLAG_POWER_KVM, > + > + GRUB_IEEE1275_FLAG_DISABLE_VIDEO_SUPPORT > }; > > extern int EXPORT_FUNC(grub_ieee1275_test_flag) (enum grub_ieee1275_flag > flag); > -- > 2.46.2 > > > _______________________________________________ > Grub-devel mailing list > Grub-devel@gnu.org > https://lists.gnu.org/mailman/listinfo/grub-devel >
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