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Re: [RFC] Proposal of marker implementation
- From: Nicholas Miell <nmiell at gmail dot com>
- To: systemtap at sources dot redhat dot com
- Date: Wed, 09 Aug 2006 21:12:44 -0700
- Subject: Re: [RFC] Proposal of marker implementation
- References: <44D97397.email@example.com>
On Wed, 09 Aug 2006 14:33:11 +0900, Masami Hiramatsu wrote:
> Each marker has 6bytes NOP. I think we can replace it with a jump code
> safely by using djprobe. Note: we can not replace it with a "call" code
> because it will break some caller-save registers.
You can use a call instruction if the function you're calling is an
assembly stub which saves caller-saved registers and then calls a C
function (passing the saved return address as a parameter so the probe
point can be located).
Alternately, you could do a normal C function call and then replace
the call instruction with NOPs as a post-processing step. This method lets
the C compiler save the caller-saved registers for you, and you can easily