Re: [PATCH] x86 ACPI: Fix breakage of resume on 64-bit UP systemswith SMP kernel

From: Pavel Machek
Date: Fri Oct 17 2008 - 04:35:44 EST

On Fri 2008-10-17 01:26:27, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@xxxxxxx>
> x86 ACPI: Fix breakage of resume on 64-bit UP systems with SMP kernel
> We are now using per CPU GDT tables in head_64.S and the original
> early_gdt_descr.address is invalidated after boot by
> setup_per_cpu_areas(). This breaks resume from suspend to RAM on
> x86_64 UP systems using SMP kernels, because this part of head_64.S
> is also executed during the resume and the invalid GDT address
> causes the system to crash. It doesn't break on 'true' SMP systems,
> because early_gdt_descr.address is modified every time
> native_cpu_up() runs. However, during resume it should point to the
> GDT of the boot CPU rather than to another CPU's GDT.
> For this reason, during suspend to RAM always make
> early_gdt_descr.address point to the boot CPU's GDT.
> This fixes, which
> is a regression from 2.6.26.
> Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
> Reported-and-tested-by: Andy Wettstein <ajw1980@xxxxxxxxx>

Acked-by: Pavel Machek <pavel@xxxxxxx>

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