J. Mayer a écrit : > On Mon, 2007-10-22 at 18:28 +0200, Aurelien Jarno wrote: >> On Mon, Oct 22, 2007 at 09:36:07AM +0200, J. Mayer wrote: >>> Hi all, >>> >>> I've been investigating more about PreP kernel boot using Qemu and I >>> achieved to boot 2.4.35, 2.6.12 and 2.6.22 kernels using Qemu CVS and >>> unmodified OHW. >>> The issues I found in the kernel are: >>> - the OpenFirmware video console driver is broken in recent 2.4 kernels >>> and have been removed from recent 2.6 kernel >>> - I then decided to use the vga16fb console driver but needed to do some >>> patches in order to make it compile properly >>> - the CMOS RTC driver is not available for PPC architecture in 2.6 >>> kernels and need some patches in order to be usable >>> - I discovered that the mkprep utility is bugged in 2.4.35 and 2.6.12 >>> kernels. The bugs are visible only when cross-compiling from a >>> little-endian and/or 64 bits host. >>> - I got issues (ie process freezing) when using the 2.6.22 kernel with >>> HZ > 100. It seems to run properly when the system timer is set to 100 >>> Hz but this needs more tests for confirmation. >>> - I got the 2.6.22 kernel crashing (ie kernel Oops in workqueue code) >>> when it has no RTC available. There is no problem when the RTC is >>> present. This is likely to be a kernel bug: when no RTC is available, it >>> cannot calibrate its timers properly and the kernel timer seems to run >>> very fast. Forcing (with hacks...) the timer to run at nearly real-time >>> seems to prevent the bug to happen. >>> >>> I then generated some kernels that allow me to boot and use those 3 >>> kernels. >>> Here are 3 tarballs with: >>> - a patch to be applied to the vanilla kernel sources to fix the >>> mentionned bugs >>> - the .config file I used to build the kernel >>> - the zImage.prep image >>> <http://perso.magic.fr/l_indien/qemu-ppc/linux-tests/linux-2.4.35-prep.tar.bz2> >>> <http://perso.magic.fr/l_indien/qemu-ppc/linux-tests/linux-2.6.12-prep.tar.bz2> >>> <http://perso.magic.fr/l_indien/qemu-ppc/linux-tests/linux-2.6.22-prep.tar.bz2> >>> >>> I then run Qemu with the following command line template: >>> ./ppc-softmmu/qemu-system-ppc -serial stdio -net nic,model=ne2k_isa -net >>> tap -net nic,model=ne2k_pci -net tap -net nic,model=rtl8139 -net tap >>> -cpu 604 -M prep -L pc-bios/ -hda <my_first_disk> -cdrom <my_cdrom> >>> -kernel >>> <src_base>/linux-<kversion>.patched/arch/ppc/boot/images/zImage.prep >>> >>> Hope this helps. >>> >> Yes, this help a lot, thanks! With your config file, I have been able to >> build and boot a 2.6.22 kernel. I have used a Debian sid chroot. >> >> Here are a few remarks: >> - The NE2000 card doesn't work for the same reason as with the powerpc >> architecture. The kernel patch below fixes the problem. I will send it >> later along with the ppc patch. > > There's something else strange with the PCI ethernet devices: they got > no IRQ assigned (as if the BIOS does not configure them properly). And > the RTL8139 never has a mac address, never detects the PHY link, then > there may be endianness issues in the emulation (I did not check at > all). > >> - The "floating point" problem I reported during the week-end does not >> exists, probably because of the switch from powerpc to ppc. I still >> don't know if it is a kernel problem or a QEMU problem (or both). > > There may be issues with the floating point emulation, especially if > some kernel or programs relies on the FPSCR (floating-point status) > register which is never updated in Qemu. >
Is there any technical reason behind that, or is it just a lack of time? -- .''`. Aurelien Jarno | GPG: 1024D/F1BCDB73 : :' : Debian developer | Electrical Engineer `. `' [EMAIL PROTECTED] | [EMAIL PROTECTED] `- people.debian.org/~aurel32 | www.aurel32.net