Re: [PATCH v10 4/5] Documentation/kbuild: Document storage of symbol information

[Petr Pavlu]

On 11/23/24 03:42, Matthew Maurer wrote:
> Document where exported and imported symbols are kept, format options,
> and limitations.
> 
> Signed-off-by: Matthew Maurer <mmaurer@xxxxxxxxxx>
> ---
>  Documentation/kbuild/modules.rst | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/Documentation/kbuild/modules.rst b/Documentation/kbuild/modules.rst
> index 101de236cd0c9abe1f5684d80063ff3f9a7fc673..c32e3ed67cd26070f6929f6ad98c4308a1ab71f8 100644
> --- a/Documentation/kbuild/modules.rst
> +++ b/Documentation/kbuild/modules.rst
> @@ -423,6 +423,26 @@ Symbols From the Kernel (vmlinux + modules)
>  	1) It lists all exported symbols from vmlinux and all modules.
>  	2) It lists the CRC if CONFIG_MODVERSIONS is enabled.
>  
> +Version Information Formats
> +---------------------------
> +
> +	Exported symbols have information stored in __ksymtab or __ksymtab_gpl
> +	sections. Symbol names and namespaces are stored in __kstrtab and
> +	__kstrtabns respectively, using a format similar to the string table
> +	used for ELF. If CONFIG_MODVERSIONS is enabled, the CRCs corresponding
> +	to exported symbols will be added to the __kcrctab or __kcrctab_gpl.

The second sentence should be that symbol names and namespaces of
exported symbols are both stored in the __ksymtab_strings section.

> +
> +	If CONFIG_BASIC_MODVERSIONS is enabled (default with
> +	CONFIG_MODVERSIONS), imported symbols will have their symbol name and
> +	CRC stored in the __versions section of the importing module. This
> +	mode only supports symbols of length up to 64 bytes.
> +
> +	If CONFIG_EXTENDED_MODVERSIONS is enabled (required to enable both
> +	CONFIG_MODVERSIONS and CONFIG_RUST at the same time), imported symbols
> +	will have their symbol name recorded in the __version_ext_names
> +	section as a series of concatenated, null-terminated strings. CRCs for
> +	these symbols will be recorded in the __version_ext_crcs section.
> +
>  Symbols and External Modules
>  ----------------------------
>  
> 

-- 
Thanks,
Petr