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From: Alan Kao <alankao@andestech.com>
To: Palmer Dabbelt <palmer@sifive.com>
Cc: <linux-riscv@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
	Greentime Hu <greentime@andestech.com>,
	Zong Li <zong@andestech.com>
Subject: Re: [PATCH] riscv/ftrace: Export _mcount when FUNCTION_GRAPH_TRACER isn't set
Date: Tue, 5 Jun 2018 09:12:29 +0800	[thread overview]
Message-ID: <20180605011228.GA31803@andestech.com> (raw)
In-Reply-To: <20180604203028.13886-2-palmer@sifive.com>

Hi Palmer,

Thanks for the refining work! But a small correction here:

On Mon, Jun 04, 2018 at 01:30:28PM -0700, Palmer Dabbelt wrote:
> From: Alan Kao <alankao@andestech.com>
> 
> The EXPORT_SYMBOL(_mcount) for RISC-V ended up inside a
> CONFIG_FUNCTION_GRAPH_TRACER ifdef.  If you enable modules without
> enabling CONFIG_FUNCTION_GRAPH_TRACER then you'll get a build error
> without this patch because the modules won't be able to find _mcount.

the export was inside a CONFIG_DYNAMIC_FTRACE section instead of
CONFIG_FUNCTION_GRAPH_TRACER.

> The new behavior is to export _mcount whenever CONFIG_FUNCTION_TRACER is
> defined.  This matches what every other architecture is doing.

Also, this patch is just a workaround and there are still issues in bringing
up ftrace for modules.  For details, please check previous emails between
Steve and me.

Thanks again for this better commit message.
Alan Kao

> 
> Signed-off-by: Alan Kao <alankao@andestech.com>
> Cc: Greentime Hu <greentime@andestech.com>
> Cc: Zong Li <zong@andestech.com>
> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
> ---
>  arch/riscv/kernel/mcount.S | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/riscv/kernel/mcount.S b/arch/riscv/kernel/mcount.S
> index ce9bdc57a2a1..5721624886a1 100644
> --- a/arch/riscv/kernel/mcount.S
> +++ b/arch/riscv/kernel/mcount.S
> @@ -126,5 +126,5 @@ do_trace:
>  	RESTORE_ABI_STATE
>  	ret
>  ENDPROC(_mcount)
> -EXPORT_SYMBOL(_mcount)
>  #endif
> +EXPORT_SYMBOL(_mcount)
> -- 
> 2.16.4
> 

      reply	other threads:[~2018-06-05  1:13 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-08  3:21 [PATCH] riscv/ftrace: Fix the problem modules cannot find _mcount Alan Kao
2018-05-08 13:11 ` Steven Rostedt
2018-05-09  2:36   ` Alan Kao
2018-05-09  3:02     ` Steven Rostedt
2018-06-04 20:30 ` Palmer Dabbelt
2018-06-04 20:30   ` [PATCH] riscv/ftrace: Export _mcount when FUNCTION_GRAPH_TRACER isn't set Palmer Dabbelt
2018-06-05  1:12     ` Alan Kao [this message]

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