Re: [PATCH] boot_cpu_data corruption on SMP x86

From: Maciej W. Rozycki (macro@ds2.pg.gda.pl)
Date: Thu Mar 21 2002 - 18:36:02 EST

On Thu, 21 Mar 2002, Mikael Pettersson wrote:

> > This is broken -- these word stores assure a proper initialization on
> >pre-CPUID processors.
>
> boot_cpu_data is a static-extent object with an explicit initialiser
> (i.e., ".data") in setup.c in 2.2.21rc2, 2.4.19-pre4, and 2.5.7.
> Any further "initialisation" by APs is called "clobbering".

 boot_cpu_data is initialized and then copied to cpu_data for each CPU
booted. If say the BSP supports cpuid but an AP does not (possible for an
i486 setup), leftover values will be stored for the AP incorrectly. 

-- 
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: macro@ds2.pg.gda.pl, PGP key available        +

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This archive was generated by hypermail 2b29 : Sat Mar 23 2002 - 22:00:26 EST