From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
To: linux-ia64@vger.kernel.org
Subject: RE: [PATCH]IA64 trap code 16 bytes atomic copy on montecito, take 2
Date: Thu, 02 Nov 2006 09:22:05 +0000 [thread overview]
Message-ID: <000401c6fe60$5e3624c0$bf80030a@amr.corp.intel.com> (raw)
In-Reply-To: <454961EE.4070608@intel.com>
Mao, Bibo wrote on Thursday, November 02, 2006 1:06 AM
> Chen, Kenneth W wrote:
> > Mao, Bibo wrote on Wednesday, November 01, 2006 11:53 PM
> >> else means that current cpu does not support 16 byte atomic operation.
> >> If kprobe address is on slot 0/2, then memcpy still can execute.
> >
> > Do you allow kprobe insertion on "L+X" instruction? It looks like so.
> > Then how do you maintain atomic update to L and X instruction right
> > now with memcpy?
>
> From the code, It allows kprobes insertion on "L+X" instruction, and put
> BREAK code on the slot 2. IA64 manual says that "the X slot may encode
> break.i and nop.i in addition to any X-unit instruction".
> It seems that for MLX, BREAK opcode should insert the higher 8 bytes firstly.
That's exactly what I'm saying in the 2nd paragraph.
> > "atomic update" is not really the exact word I want to use here. Don't
> > you want to write the upper 8-byte first so that break opcode is jammed
> > in there before updating the remaining 41-bit immediate value? Otherwise,
> > writing lower 8-byte first will end up with a small window that original
> > opcode seeing corrupted immediate value.
And same logic extends to inserting probe on slot 1 instruction. The key is
to jam in break opcode, before updating the remaining unused immediate value.
next prev parent reply other threads:[~2006-11-02 9:22 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-11-02 3:11 [PATCH]IA64 trap code 16 bytes atomic copy on montecito, take 2 bibo,mao
2006-11-02 3:39 ` Keith Owens
2006-11-02 5:04 ` [PATCH]IA64 trap code 16 bytes atomic copy on montecito, take bibo,mao
2006-11-02 6:51 ` bibo,mao
2006-11-02 7:17 ` [PATCH]IA64 trap code 16 bytes atomic copy on montecito, take 2 Keith Owens
2006-11-02 7:22 ` Keith Owens
2006-11-02 7:25 ` Keith Owens
2006-11-02 7:27 ` [PATCH]IA64 trap code 16 bytes atomic copy on montecito, take bibo,mao
2006-11-02 7:32 ` [PATCH]IA64 trap code 16 bytes atomic copy on montecito, take 2 Keith Owens
2006-11-02 7:38 ` Chen, Kenneth W
2006-11-02 7:45 ` Chen, Kenneth W
2006-11-02 7:52 ` [PATCH]IA64 trap code 16 bytes atomic copy on montecito, take bibo,mao
2006-11-02 8:17 ` [PATCH]IA64 trap code 16 bytes atomic copy on montecito, take 2 Chen, Kenneth W
2006-11-02 8:56 ` Chen, Kenneth W
2006-11-02 9:05 ` [PATCH]IA64 trap code 16 bytes atomic copy on montecito, take bibo,mao
2006-11-02 9:22 ` Chen, Kenneth W [this message]
2006-11-02 19:50 ` [PATCH]IA64 trap code 16 bytes atomic copy on montecito, take 2 Chen, Kenneth W
2006-11-02 19:57 ` Luck, Tony
2006-11-02 20:29 ` Chen, Kenneth W
2006-11-03 1:25 ` [PATCH]IA64 trap code 16 bytes atomic copy on montecito, take bibo,mao
2006-11-03 1:55 ` [PATCH]IA64 trap code 16 bytes atomic copy on montecito, take 2 Chen, Kenneth W
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