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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
	linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org,
	Steven Rostedt <srostedt@redhat.com>,
	Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@elte.hu>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 3/7][RFC] powerpc64, tracing: add function graph tracer with dynamic tracing
Date: Fri, 13 Feb 2009 15:15:09 +1100	[thread overview]
Message-ID: <1234498509.26036.35.camel@pasglop> (raw)
In-Reply-To: <20090212011343.074329920@goodmis.org>


> @@ -55,8 +56,9 @@ static unsigned char *ftrace_call_replace(unsigned
> long ip, unsigned long addr)
>  	 */
>  	addr = GET_ADDR(addr);
>  
> -	/* Set to "bl addr" */
> -	op = 0x48000001 | (ftrace_calc_offset(ip, addr) & 0x03fffffc);
> +	/* if (link) set op to 'bl' else 'b' */
> +	op = 0x48000000 | (link ? 1 : 0);
> +	op |= (ftrace_calc_offset(ip, addr) & 0x03fffffc);

Any reason why you aren't using the code in
arch/powerpc/lib/code-patching.c here ?

> 	new = ftrace_call_replace(ip, stub, 0);
> +	memcpy(old, new, MCOUNT_INSN_SIZE);
> +	new = ftrace_call_replace(ip, addr, 0);
> +
> +	return ftrace_modify_code(ip, old, new);
> +}

Heh, memcpy of 4 bytes :-) I hope gcc is smart enough to turn that into
a simple load/store ..

Cheers,
Ben.

WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
	Andrew Morton <akpm@linux-foundation.org>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	linuxppc-dev@ozlabs.org, Paul Mackerras <paulus@samba.org>,
	Steven Rostedt <srostedt@redhat.com>
Subject: Re: [PATCH 3/7][RFC] powerpc64, tracing: add function graph tracer with dynamic tracing
Date: Fri, 13 Feb 2009 15:15:09 +1100	[thread overview]
Message-ID: <1234498509.26036.35.camel@pasglop> (raw)
In-Reply-To: <20090212011343.074329920@goodmis.org>


> @@ -55,8 +56,9 @@ static unsigned char *ftrace_call_replace(unsigned
> long ip, unsigned long addr)
>  	 */
>  	addr = GET_ADDR(addr);
>  
> -	/* Set to "bl addr" */
> -	op = 0x48000001 | (ftrace_calc_offset(ip, addr) & 0x03fffffc);
> +	/* if (link) set op to 'bl' else 'b' */
> +	op = 0x48000000 | (link ? 1 : 0);
> +	op |= (ftrace_calc_offset(ip, addr) & 0x03fffffc);

Any reason why you aren't using the code in
arch/powerpc/lib/code-patching.c here ?

> 	new = ftrace_call_replace(ip, stub, 0);
> +	memcpy(old, new, MCOUNT_INSN_SIZE);
> +	new = ftrace_call_replace(ip, addr, 0);
> +
> +	return ftrace_modify_code(ip, old, new);
> +}

Heh, memcpy of 4 bytes :-) I hope gcc is smart enough to turn that into
a simple load/store ..

Cheers,
Ben.


  reply	other threads:[~2009-02-13  4:15 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-02-12  1:10 [PATCH 0/7][RFC] function graph tracer port to PowerPC Steven Rostedt
2009-02-12  1:10 ` Steven Rostedt
2009-02-12  1:10 ` [PATCH 1/7][RFC] tracing/function-graph-tracer: make arch generic push pop functions Steven Rostedt
2009-02-12  1:10   ` Steven Rostedt
2009-02-12  1:10 ` [PATCH 2/7][RFC] powerpc64: port of the function graph tracer Steven Rostedt
2009-02-12  1:10   ` Steven Rostedt
2009-02-13  4:12   ` Benjamin Herrenschmidt
2009-02-13  4:12     ` Benjamin Herrenschmidt
2009-02-13  4:18     ` Steven Rostedt
2009-02-13  4:18       ` Steven Rostedt
2009-02-12  1:10 ` [PATCH 3/7][RFC] powerpc64, tracing: add function graph tracer with dynamic tracing Steven Rostedt
2009-02-12  1:10   ` Steven Rostedt
2009-02-13  4:15   ` Benjamin Herrenschmidt [this message]
2009-02-13  4:15     ` Benjamin Herrenschmidt
2009-02-13  4:20     ` Steven Rostedt
2009-02-13  4:20       ` Steven Rostedt
2009-02-13  5:22     ` Steven Rostedt
2009-02-13  5:22       ` Steven Rostedt
2009-02-12  1:10 ` [PATCH 4/7][RFC] powerpc64, ftrace: save toc only on modules for function graph Steven Rostedt
2009-02-12  1:10   ` Steven Rostedt
2009-02-12  1:10 ` [PATCH 5/7][RFC] powerpc32, ftrace: save and restore mcount regs with macro Steven Rostedt
2009-02-12  1:10   ` Steven Rostedt
2009-02-12  1:10 ` [PATCH 6/7][RFC] powerpc32, ftrace: port function graph tracer to ppc32, static only Steven Rostedt
2009-02-12  1:10   ` Steven Rostedt
2009-02-12  1:10 ` [PATCH 7/7][RFC] powerpc32, ftrace: dynamic function graph tracer Steven Rostedt
2009-02-12  1:10   ` Steven Rostedt
2009-02-12  1:55 ` [PATCH 0/7][RFC] function graph tracer port to PowerPC Frederic Weisbecker
2009-02-12  1:55   ` Frederic Weisbecker
2009-02-12  2:16   ` Steven Rostedt
2009-02-12  2:16     ` Steven Rostedt
2009-02-12  4:08     ` Frederic Weisbecker
2009-02-12  4:08       ` Frederic Weisbecker
2009-02-12 16:31   ` Steven Rostedt
2009-02-12 16:31     ` Steven Rostedt
2009-02-12 16:47     ` Frederic Weisbecker
2009-02-12 16:47       ` Frederic Weisbecker
2009-02-12 16:58       ` Steven Rostedt
2009-02-12 16:58         ` Steven Rostedt
2009-02-13  4:18   ` Benjamin Herrenschmidt
2009-02-13  4:18     ` Benjamin Herrenschmidt
2009-02-12  2:23 ` Michael Ellerman
2009-02-12  2:23   ` Michael Ellerman
2009-02-12  2:37   ` Steven Rostedt
2009-02-12  2:37     ` Steven Rostedt
2009-02-12 16:35 ` Steven Rostedt
2009-02-12 16:35   ` Steven Rostedt
2009-02-12 23:32 ` Geoff Levand
2009-02-12 23:32   ` Geoff Levand
2009-02-12 23:41   ` Steven Rostedt
2009-02-12 23:41     ` Steven Rostedt
2009-02-12 23:44     ` Josh Boyer
2009-02-12 23:44       ` Josh Boyer
2009-02-12 23:44     ` Geoff Levand
2009-02-12 23:44       ` Geoff Levand
2009-02-12 23:51       ` Steven Rostedt
2009-02-12 23:51         ` Steven Rostedt

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