From: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
To: David Daney <ddaney.cavm@gmail.com>
Cc: James Hogan <james.hogan@imgtec.com>, <linux-mips@linux-mips.org>,
<Zubair.Kakakhel@imgtec.com>, <geert+renesas@glider.be>,
<david.daney@cavium.com>, <peterz@infradead.org>,
<paul.gortmaker@windriver.com>, <davidlohr@hp.com>,
<macro@linux-mips.org>, <chenhc@lemote.com>, <richard@nod.at>,
<zajec5@gmail.com>, <keescook@chromium.org>,
<alex@alex-smith.me.uk>, <tglx@linutronix.de>,
<blogic@openwrt.org>, <jchandra@broadcom.com>,
<paul.burton@imgtec.com>, <qais.yousef@imgtec.com>,
<linux-kernel@vger.kernel.org>, <ralf@linux-mips.org>,
<markos.chandras@imgtec.com>, <dengcheng.zhu@imgtec.com>,
<manuel.lauss@gmail.com>, <akpm@linux-foundation.org>,
<lars.persson@axis.com>
Subject: Re: [PATCH v2 2/3] MIPS: Setup an instruction emulation in VDSO protected page instead of user stack
Date: Fri, 10 Oct 2014 16:40:26 -0700 [thread overview]
Message-ID: <54386E6A.8060108@imgtec.com> (raw)
In-Reply-To: <54386438.9090606@gmail.com>
On 10/10/2014 03:56 PM, David Daney wrote:
>
>> > Right, look at uprobes, it does exactly all this with a single page.
>> > Slot allocation will block waiting for a free slot when all are in
>> use.
>>
>> I don't see a reason to change my 300 lines design into much more
>> lengthy code. That code has more links to the rest of kernel and high
>> possibility to execute atomic operation/locks/mutex/etc - I can't do it
>> for emulation of MIPS locking instructions.
>>
>
> It isn't just the number of lines of code that is important.
>
> Doesn't your solution consume an extra page for each thread requiring
> emulation? That could be a significant amount of memory in a system
> with many threads.
Yes, you right. However, per-thread memory is useful for many goals.
>
> Are you are using this to emulate atomic operations in addition to FPU
> branch delay slot instructions? Where is the code that does that?
Yes, in MIPS R2 emulator - MIPS R6 changed LL/LLD/SC/SCD opcodes and
offset size.
The code-in-developement is in
ssh://git.linux-mips.org/pub/scm/yegoshin/mips.git, branch
android-linux-mti-3.10.14
- Leonid.
WARNING: multiple messages have this Message-ID (diff)
From: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
To: David Daney <ddaney.cavm@gmail.com>
Cc: James Hogan <james.hogan@imgtec.com>,
linux-mips@linux-mips.org, Zubair.Kakakhel@imgtec.com,
geert+renesas@glider.be, david.daney@cavium.com,
peterz@infradead.org, paul.gortmaker@windriver.com,
davidlohr@hp.com, macro@linux-mips.org, chenhc@lemote.com,
richard@nod.at, zajec5@gmail.com, keescook@chromium.org,
alex@alex-smith.me.uk, tglx@linutronix.de, blogic@openwrt.org,
jchandra@broadcom.com, paul.burton@imgtec.com,
qais.yousef@imgtec.com, linux-kernel@vger.kernel.org,
ralf@linux-mips.org, markos.chandras@imgtec.com,
dengcheng.zhu@imgtec.com, manuel.lauss@gmail.com,
akpm@linux-foundation.org, lars.persson@axis.com
Subject: Re: [PATCH v2 2/3] MIPS: Setup an instruction emulation in VDSO protected page instead of user stack
Date: Fri, 10 Oct 2014 16:40:26 -0700 [thread overview]
Message-ID: <54386E6A.8060108@imgtec.com> (raw)
Message-ID: <20141010234026.6LAIBWUxlX27mu4J-KvloIV90CjAfmebPXh_HHFCTUk@z> (raw)
In-Reply-To: <54386438.9090606@gmail.com>
On 10/10/2014 03:56 PM, David Daney wrote:
>
>> > Right, look at uprobes, it does exactly all this with a single page.
>> > Slot allocation will block waiting for a free slot when all are in
>> use.
>>
>> I don't see a reason to change my 300 lines design into much more
>> lengthy code. That code has more links to the rest of kernel and high
>> possibility to execute atomic operation/locks/mutex/etc - I can't do it
>> for emulation of MIPS locking instructions.
>>
>
> It isn't just the number of lines of code that is important.
>
> Doesn't your solution consume an extra page for each thread requiring
> emulation? That could be a significant amount of memory in a system
> with many threads.
Yes, you right. However, per-thread memory is useful for many goals.
>
> Are you are using this to emulate atomic operations in addition to FPU
> branch delay slot instructions? Where is the code that does that?
Yes, in MIPS R2 emulator - MIPS R6 changed LL/LLD/SC/SCD opcodes and
offset size.
The code-in-developement is in
ssh://git.linux-mips.org/pub/scm/yegoshin/mips.git, branch
android-linux-mti-3.10.14
- Leonid.
next prev parent reply other threads:[~2014-10-10 23:40 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-09 20:00 [PATCH v2 0/3] MIPS executable stack protection Leonid Yegoshin
2014-10-09 20:00 ` Leonid Yegoshin
2014-10-09 20:00 ` [PATCH v2 1/3] MIPS: mips_flush_cache_range is added Leonid Yegoshin
2014-10-09 20:00 ` Leonid Yegoshin
2014-10-09 20:00 ` [PATCH v2 2/3] MIPS: Setup an instruction emulation in VDSO protected page instead of user stack Leonid Yegoshin
2014-10-09 20:00 ` Leonid Yegoshin
2014-10-09 22:43 ` James Hogan
2014-10-09 22:43 ` James Hogan
2014-10-09 23:10 ` Leonid Yegoshin
2014-10-09 23:10 ` Leonid Yegoshin
2014-10-09 23:40 ` James Hogan
2014-10-09 23:40 ` James Hogan
2014-10-10 0:07 ` Leonid Yegoshin
2014-10-10 0:07 ` Leonid Yegoshin
2014-10-10 10:03 ` James Hogan
2014-10-10 10:03 ` James Hogan
2014-10-10 10:24 ` Peter Zijlstra
2014-10-10 22:47 ` Leonid Yegoshin
2014-10-10 22:47 ` Leonid Yegoshin
2014-10-10 22:56 ` David Daney
2014-10-10 23:40 ` Leonid Yegoshin [this message]
2014-10-10 23:40 ` Leonid Yegoshin
2014-10-09 20:00 ` [PATCH v2 3/3] MIPS: set stack/data protection as non-executable Leonid Yegoshin
2014-10-09 20:00 ` Leonid Yegoshin
2014-10-09 21:42 ` [PATCH v2 0/3] MIPS executable stack protection David Daney
2014-10-09 22:18 ` Leonid Yegoshin
2014-10-09 22:18 ` Leonid Yegoshin
2014-10-09 22:28 ` Paul Burton
2014-10-09 22:28 ` Paul Burton
2014-10-09 22:59 ` David Daney
2014-10-09 22:59 ` David Daney
2014-10-09 23:48 ` Leonid Yegoshin
2014-10-09 23:48 ` Leonid Yegoshin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=54386E6A.8060108@imgtec.com \
--to=leonid.yegoshin@imgtec.com \
--cc=Zubair.Kakakhel@imgtec.com \
--cc=akpm@linux-foundation.org \
--cc=alex@alex-smith.me.uk \
--cc=blogic@openwrt.org \
--cc=chenhc@lemote.com \
--cc=david.daney@cavium.com \
--cc=davidlohr@hp.com \
--cc=ddaney.cavm@gmail.com \
--cc=dengcheng.zhu@imgtec.com \
--cc=geert+renesas@glider.be \
--cc=james.hogan@imgtec.com \
--cc=jchandra@broadcom.com \
--cc=keescook@chromium.org \
--cc=lars.persson@axis.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mips@linux-mips.org \
--cc=macro@linux-mips.org \
--cc=manuel.lauss@gmail.com \
--cc=markos.chandras@imgtec.com \
--cc=paul.burton@imgtec.com \
--cc=paul.gortmaker@windriver.com \
--cc=peterz@infradead.org \
--cc=qais.yousef@imgtec.com \
--cc=ralf@linux-mips.org \
--cc=richard@nod.at \
--cc=tglx@linutronix.de \
--cc=zajec5@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.