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Re: Hitachi djprobe mechanism
- From: Roland McGrath <roland at redhat dot com>
- To: Masami Hiramatsu <hiramatu at sdl dot hitachi dot co dot jp>
- Cc: Richard J Moore <richardj_moore at uk dot ibm dot com>,SystemTAP <systemtap at sources dot redhat dot com>, sugita at sdl dot hitachi dot co dot jp,Satoshi Oshima <soshima at redhat dot com>
- Date: Tue, 26 Jul 2005 00:53:46 -0700 (PDT)
- Subject: Re: Hitachi djprobe mechanism
> I think Kerninst is similar in effect to djprobe. both of them copy
> original code to a buffer and jump to the buffer.
> However I think that the most unique feature of djprobe is use of
> "bypass" route to safely insert code on SMP.
> I cannot find SMP safety mechanism like "bypass" in kerninst papers
> yet.
If by this you mean inserting an int3 while writing the rest of the jmp
instruction and then overwriting the first byte when the rest is in place,
I recall reading about that in some kerninst paper to be sure.