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Re: Cannot unwind through MIPS signal frames with ICACHE_REFILLS_WORKARO

To: "Franck Bui-Huu" <>, "Ralf Baechle" <>
Subject: Re: Cannot unwind through MIPS signal frames with ICACHE_REFILLS_WORKAROUND_WAR
From: "Kevin D. Kissell" <>
Date: Tue, 13 Nov 2007 15:37:39 +0100
Cc: "Andrew Haley" <>, "David Daney" <>, <>, "Richard Sandiford" <>, <>
Original-recipient: rfc822;
References: <> <> <> <>
Franck a dit:
> > Another reason is to get rid of the classic trampoline the kernel installs
> > on the stack.  On some multiprocessor systems it requires a cacheflush
> > operation to be performed on all processors which is expensive.  Having
> > the trampoline in a vDSO would solve that.
> >
> And the stack wouldn't need to have exec permission anymore.

True, though it should perhaps be noted that currently it's only on 4KSc/Sd
systems (which I know you work on) where it's even possible for the stack
*not* to have exec permissions, since the classical MIPS MMU gives
execute permission to any page that is readable.


            Kevin K.

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