On Mon, 2014-10-20 at 22:21 +0100, Ben Harris wrote: > Package: linux > Version: 3.16.5-1 > Version: 3.16.3-2 > Version: 3.2.57-3 > Version: linux-2.6/2.6.31-1 > Severity: important > > Attempting to boot the kernel in linux-image-3.16-3-486 on a Soekris > Engineering net4501 fails. With "console=ttyS0 earlyprintk=serial" on the > kernel command-line, I get the following on the serial console: > > > Loading Linux 3.16-3-486 ... > Loading initial ramdisk ... > early console in decompress_kernel > > Decompressing Linux... Parsing ELF... No relocation needed... done. > Booting the kernel. > > > No output appears on the console after that. I'm using grub-pc > 1.99-27+deb7u2, and the BIOS is comBIOS 1.33 (the last one released for > the net4501). The net4501 is built around an AMD Élan SC520, which has a > 486 core. > > If I recompile the kernel using the following procedure, I get one that > boots: > > $ debian/rules setup > $ make O=debian/build/build_i386_none_486 CC=/usr/lib/ccache/gcc-4.8 menuconfig > [ disable stack protector (setting CC_STACKPROTECTOR_NONE) ] > $ make -j2 O=debian/build/build_i386_none_486 CC=/usr/lib/ccache/gcc-4.8 bzImage > > This suggests that the kernel stack protector is what's causing the > problem. > > The same bug seems to have existed since Debian first enabled the kernel > stack protector back in 2.6.31. I've tested the versions listed in the > pseudo-headers. It appears that the stack protector depends on the TSC for initialisation. This is not implemented by the Intel 486 or its clones. We should perhaps have renamed the 486 flavour to 586 when enabling this feature, but it wasn't noticed at the time. It's a bit late to change the flavour name for jessie, as it is unfortunately used in many other places. I can at least correct the description. I don't think we will add support for 486 processors again, in fact I would like to drop this flavour entirely in time for the next release. Ben. -- Ben Hutchings Reality is just a crutch for people who can't handle science fiction.
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