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Date: Wed, 18 Jan 2012 14:32:32 +0530
From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Oleg Nesterov <oleg@redhat.com>, Ingo Molnar <mingo@elte.hu>,
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        Arnaldo Carvalho de Melo <acme@infradead.org>,
        Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
        Jim Keniston <jkenisto@linux.vnet.ibm.com>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Mike Frysinger <vapier@gentoo.org>
Subject: Re: [PATCH v9 3.2 2/9] uprobes: handle breakpoint and signal step
 exception.
Message-ID: <20120118090232.GE15447@linux.vnet.ibm.com>
Reply-To: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
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> Srikar,
> 
>   Can we use existing SET_IP() instead of set_instruction_pointer() ?
> 

Oleg had already commented about this in one his uprobes reviews.

The GET_IP/SET_IP available in include/asm-generic/ptrace.h doesnt work
on all archs. Atleast it doesnt work on powerpc when I tried it.

Also most archs define instruction_pointer(). So I thought (rather Peter
Zijlstra suggested the name set_instruction_pointer())
set_instruction_pointer was a better bet than SET_IP. I 

Also I dont see any usage for SET_IP/GET_IP.

May be we should have something like this in
include/asm-generic/ptrace.h

#ifdef instruction_pointer
#define GET_IP(regs)		(instruction_pointer(regs))

#define set_instruction_pointer(regs, val) (instruction_pointer(regs) = (val))

#define SET_IP(regs, val)	(set_instruction_pointer(regs,val))

#endif

or should we do away with GET_IP/SET_IP esp since there are no many
users?

-- 
Thanks and Regards
Srikar