From: "Kevin D. Kissell" <kevink@mips.com>
To: "Franck Bui-Huu" <vagabon.xyz@gmail.com>,
"Ralf Baechle" <ralf@linux-mips.org>
Cc: "Andrew Haley" <aph-gcc@littlepinkcloud.com>,
"David Daney" <ddaney@avtrex.com>, <linux-mips@linux-mips.org>,
"Richard Sandiford" <rsandifo@nildram.co.uk>, <gcc@gcc.gnu.org>
Subject: Re: Cannot unwind through MIPS signal frames with ICACHE_REFILLS_WORKAROUND_WAR
Date: Tue, 13 Nov 2007 15:37:39 +0100 [thread overview]
Message-ID: <019e01c82602$f5463bf0$10eca8c0@grendel> (raw)
In-Reply-To: cda58cb80711130514x16356ea3x4069616c9ee3caac@mail.gmail.com
Franck a dit:
> > Another reason is to get rid of the classic trampoline the kernel installs
> > on the stack. On some multiprocessor systems it requires a cacheflush
> > operation to be performed on all processors which is expensive. Having
> > the trampoline in a vDSO would solve that.
> >
>
> And the stack wouldn't need to have exec permission anymore.
True, though it should perhaps be noted that currently it's only on 4KSc/Sd
systems (which I know you work on) where it's even possible for the stack
*not* to have exec permissions, since the classical MIPS MMU gives
execute permission to any page that is readable.
Regards,
Kevin K.
WARNING: multiple messages have this Message-ID (diff)
From: "Kevin D. Kissell" <kevink@mips.com>
To: Franck Bui-Huu <vagabon.xyz@gmail.com>,
Ralf Baechle <ralf@linux-mips.org>
Cc: Andrew Haley <aph-gcc@littlepinkcloud.com>,
David Daney <ddaney@avtrex.com>,
linux-mips@linux-mips.org,
Richard Sandiford <rsandifo@nildram.co.uk>,
gcc@gcc.gnu.org
Subject: Re: Cannot unwind through MIPS signal frames with ICACHE_REFILLS_WORKAROUND_WAR
Date: Tue, 13 Nov 2007 15:37:39 +0100 [thread overview]
Message-ID: <019e01c82602$f5463bf0$10eca8c0@grendel> (raw)
Message-ID: <20071113143739.DTtxlTrKBV8XKm9Gm7Asn8Luqg6o1B6Ejz3h5tbsYHU@z> (raw)
In-Reply-To: cda58cb80711130514x16356ea3x4069616c9ee3caac@mail.gmail.com
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.
Regards,
Kevin K.
next prev parent reply other threads:[~2007-11-13 14:47 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-13 7:52 Cannot unwind through MIPS signal frames with ICACHE_REFILLS_WORKAROUND_WAR David Daney
2007-11-13 11:48 ` Andrew Haley
2007-11-13 12:10 ` Ralf Baechle
2007-11-13 13:14 ` Franck Bui-Huu
2007-11-13 14:00 ` Ralf Baechle
2007-11-13 14:22 ` Franck Bui-Huu
2007-11-13 15:01 ` Ralf Baechle
2007-11-13 22:11 ` Andrew Pinski
2007-11-13 14:37 ` Kevin D. Kissell [this message]
2007-11-13 14:37 ` Kevin D. Kissell
2007-11-13 14:49 ` Franck Bui-Huu
2007-11-13 15:08 ` Ralf Baechle
2007-11-13 22:49 ` Cannot unwind through MIPS signal frames withICACHE_REFILLS_WORKAROUND_WAR Kevin D. Kissell
2007-11-13 22:49 ` Kevin D. Kissell
2007-11-13 21:26 ` VDSO on mips (was Re: Cannot unwind through MIPS signal frames with ICACHE_REFILLS_WORKAROUND_WAR) Franck Bui-Huu
2007-11-15 8:46 ` Cannot unwind through MIPS signal frames with ICACHE_REFILLS_WORKAROUND_WAR Franck Bui-Huu
2007-11-15 11:53 ` Ralf Baechle
2007-11-15 17:21 ` David Daney
2007-11-17 8:38 ` Franck Bui-Huu
2007-11-13 16:12 ` David Daney
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