linux/arch
Joerg Roedel 7b27718bdb x86: fix setup code crashes on my old 486 box
yesterday I tried to reactivate my old 486 box and wanted to install a
current Linux with latest kernel on it. But it turned out that the
latest kernel does not boot because the machine crashes early in the
setup code.

After some debugging it turned out that the problem is the query_ist()
function. If this interrupt with that function is called the machine
simply locks up. It looks like a BIOS bug. Looking for a workaround for
this problem I wrote the attached patch. It checks for the CPUID
instruction and if it is not implemented it does not call the speedstep
BIOS function. As far as I know speedstep should be available since some
Pentium earliest.

Alan Cox observed that it's available since the Pentium II, so cpuid
levels 4 and 5 can be excluded altogether.

H. Peter Anvin cleaned up the code some more:

> Right in concept, but I dislike the implementation (duplication of the
> CPU detect code we already have).  Could you try this patch and see if
> it works for you?

which, with a small modification to fix a build error with it the
resulting kernel boots on my machine.

Signed-off-by: Joerg Roedel <joro@8bytes.org>
Signed-off-by: "H. Peter Anvin" <hpa@zytor.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-13 11:59:18 +02:00
..
alpha [PATCH] sanitize __user_walk_fd() et.al. 2008-07-26 20:53:34 -04:00
arm Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6 2008-07-28 18:14:24 -07:00
avr32 avr32: some mmc/sd cleanups 2008-07-27 13:57:36 +02:00
blackfin
cris Merge branch 'linus' into core/generic-dma-coherent 2008-07-29 00:07:55 +02:00
frv
h8300
ia64 KVM: ia64: Fix irq disabling leak in error handling code 2008-07-27 11:35:32 +03:00
m32r
m68k
m68knommu
mips
mn10300
parisc [PATCH] sanitize __user_walk_fd() et.al. 2008-07-26 20:53:34 -04:00
powerpc powerpc: Disable 64K hugetlb support when doing 64K SPU mappings 2008-07-28 16:30:53 +10:00
s390 stop_machine: Wean existing callers off stop_machine_run() 2008-07-28 12:16:31 +10:00
sh Merge branch 'linus' into core/generic-dma-coherent 2008-07-29 00:07:55 +02:00
sparc sparc: Set CONFIG_HAVE_ARCH_TRACEHOOK 2008-07-27 17:34:02 -07:00
sparc64 sparc64: tracehook: CONFIG_HAVE_ARCH_TRACEHOOK 2008-07-27 17:33:07 -07:00
um
x86 x86: fix setup code crashes on my old 486 box 2008-08-13 11:59:18 +02:00
xtensa
.gitignore
Kconfig