Subject: Re: [patch 1/3] powerpc: Move 64bit VDSO to improve context switch performance

From: Andreas Schwab <[email-masked]>
Date: Sat, 03 Oct 2009 16:15:38 +0200

Andreas Schwab <[email-masked]> writes:

> Anton Blanchard <[email-masked]> writes:
>
>> On 64bit applications the VDSO is the only thing in segment 0. Since the VDSO
>> is position independent we can remove the hint and let get_unmapped_area pick
>> an area.
>
> This breaks gdb.  The section table in the VDSO image when mapped into
> the process no longer contains meaningful values, and gdb rejects it.

The problem is that the load segment requires 64k alignment, but the
page allocater of course only provides PAGE_SIZE alignment, causing the
image to be unaligned in memory.

Andreas.

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Andreas Schwab, [email-masked]
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