linux-kernel - Re: [PATCH v4 1/2] remoteproc: elf_loader: Update resource table name check

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Date:   Wed, 4 Jan 2023 16:15:52 -0700
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Srinivasa Rao Mandadapu <quic_srivasam@...cinc.com>
Cc:     linux-remoteproc@...r.kernel.org, agross@...nel.org,
        andersson@...nel.org, lgirdwood@...il.com, broonie@...nel.org,
        robh+dt@...nel.org, quic_plai@...cinc.com, bgoswami@...cinc.com,
        perex@...ex.cz, tiwai@...e.com, srinivas.kandagatla@...aro.org,
        quic_rohkumar@...cinc.com, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org, swboyd@...omium.org,
        judyhsiao@...omium.org, devicetree@...r.kernel.org,
        krzysztof.kozlowski@...aro.org, corbet@....net
Subject: Re: [PATCH v4 1/2] remoteproc: elf_loader: Update resource table
 name check

On Wed, Dec 21, 2022 at 11:40:32AM +0530, Srinivasa Rao Mandadapu wrote:
> Update the way of checking resource table name with prefix substring search
> instead of complete string search.
> 
> In general, Qualcomm DSP binary is prepared by combining different ELFs'.
> Hence, section header name (e.g. .resource_table), appended with ELF name
> to differentiate with same section(e.g. resource_table.ac_bin_process) of
> different ELFs'.
>

Well, they are different ELF files so it is implied the resource section may be
different...  And from what I see this is purely a human thing and not
specifically needed by machines.  

I can't imagine this is a new situation and as such must ask how it was working
before?

> Example readelf output of DSP binary:
>     [60] .start.ac_bin_process PROGBITS
>     [61] .resource_table.ac_bin_process PROGBITS

The real question is...  Why is this labeled ".resource_table.ac_bin_process"
rather than simply ".resource_table"?

>     [62] .comment.ac_bin_process PROGBITS
> 
> Signed-off-by: Srinivasa Rao Mandadapu <quic_srivasam@...cinc.com>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@...aro.org>
> Reviewed-by: Mukesh Ojha <quic_mojha@...cinc.com>
> ---
>  drivers/remoteproc/remoteproc_elf_loader.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/remoteproc/remoteproc_elf_loader.c b/drivers/remoteproc/remoteproc_elf_loader.c
> index 5a412d7..77330d6 100644
> --- a/drivers/remoteproc/remoteproc_elf_loader.c
> +++ b/drivers/remoteproc/remoteproc_elf_loader.c
> @@ -272,7 +272,7 @@ find_table(struct device *dev, const struct firmware *fw)
>  		u64 offset = elf_shdr_get_sh_offset(class, shdr);
>  		u32 name = elf_shdr_get_sh_name(class, shdr);
>  
> -		if (strcmp(name_table + name, ".resource_table"))
> +		if (!strstarts(name_table + name, ".resource_table"))
>  			continue;
>  
>  		table = (struct resource_table *)(elf_data + offset);
> -- 
> 2.7.4
>