Re: 2.6.39-rc5-git2 boot crashs

From: Linus Torvalds
Date: Tue May 03 2011 - 17:46:13 EST


On Tue, May 3, 2011 at 1:50 PM, Ingo Molnar <mingo@xxxxxxx> wrote:
>
> the ELAN .config option influences the following details:
>
>  - sets X86_L1_CACHE_SHIFT to 4 (16 bytes) instead of the typical 6 (64 bytes)
>  - sets X86_ALIGNMENT_16
>  - sets the -march=i486 compiler flag

It also does this to the config diff:

306,307c328,332
< CONFIG_X86_ALIGNMENT_16=y
< CONFIG_X86_MINIMUM_CPU_FAMILY=4
---
> CONFIG_X86_USE_PPRO_CHECKSUM=y
> CONFIG_X86_TSC=y
> CONFIG_X86_CMPXCHG64=y
> CONFIG_X86_CMOV=y
> CONFIG_X86_MINIMUM_CPU_FAMILY=5

because of all the indirect changes it causes.

Now, Werner is actually _running_ on an AMD Opteron (or whatever
family 15 is), I think. And his kernel is SMP-enabled. And that whole
thin looks really really iffy.

How/why do we even allow that combination of SMP and (for example)
arch/x86/lib/atomic64_386_32.S to be picked?

I don't think he actually runs SMP, but the fact that we even allow
that combination looks really odd/iffy. Am I missing something?

Linus
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