Re: [PATCH 2/9] x86 idle: remove NOP cpuinfo_x86.hlt_works_ok flag

[Ingo Molnar]

* Len Brown <lenb@xxxxxxxxxx> wrote:

> From: Len Brown <len.brown@xxxxxxxxx>
> 
> hlt_works_ok was X86_32 only, initialized to 1, and never cleared.
> 
> On 32-bit kernels, this deletes a line from /proc/cpuinfo: "hlt_bug : no"

I think you missed the valid usecase where an old CPU with broken halt is 
booted with the no-hlt boot parameter and does not want to crash in the HLT 
instruction.

That "no-hlt" boot parameter does:

  arch/x86/kernel/cpu/bugs.c:     boot_cpu_data.hlt_works_ok = 0;

We can restrict compatibility, but *please* lets do it *explicitly*, not under 
some 'remove unused code' pretense ...

Could you please list all CPU models that are affected?

Thanks,

	Ingo
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