On Wed, Feb 25, 2015 at 8:53 AM, Michal Marek <mmarek@xxxxxxx> wrote:
> On Tue, Feb 24, 2015 at 10:02:55PM -0300, Lucas De Marchi wrote:
>> On Mon, Feb 23, 2015 at 12:51 PM, Michal Marek <mmarek@xxxxxxx> wrote:
>> > On 2015-02-23 15:30, Lucas De Marchi wrote:
>> >> My questions are:
>> >> 1) should we put *all* the "modules" in the builtin index?
>> >
>> > You mean all *.o files that do not end up in some *.ko? That won't work,
>> > because unlike module names, the names of object files are not global.
>>
>> I was actually meaning anything that can have a directory under
>> /sys/module/. I figure we can't easily know this.
>
> I see. Well, we could generate the .modinfo section also for builtin
> object files and discard it from vmlinux later, like this:
>
> diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
> index ac78910..efe1798 100644
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@ -683,6 +683,7 @@
> EXIT_CALL \
> *(.discard) \
> *(.discard.*) \
> + *(.modinfo) \
> }
>
> /**
> diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
> index 1c9effa..f38abfa 100644
> --- a/include/linux/moduleparam.h
> +++ b/include/linux/moduleparam.h
> @@ -16,23 +16,17 @@
> /* Chosen so that structs with an unsigned long line up. */
> #define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long))
>
> -#ifdef MODULE
> #define __MODULE_INFO(tag, name, info) \
> static const char __UNIQUE_ID(name)[] \
> __used __attribute__((section(".modinfo"), unused, aligned(1))) \
> = __stringify(tag) "=" info
> -#else /* !MODULE */
> -/* This struct is here for syntactic coherency, it is not used */
> -#define __MODULE_INFO(tag, name, info) \
> - struct __UNIQUE_ID(name) {}
> -#endif
> #define __MODULE_PARM_TYPE(name, _type) \
> - __MODULE_INFO(parmtype, name##type, #name ":" _type)
> + __MODULE_INFO(parmtype, name##type, MODULE_PARAM_PREFIX #name ":" _type)
>
> /* One for each parameter, describing how to use it. Some files do
> multiple of these per line, so can't just use MODULE_INFO. */
> #define MODULE_PARM_DESC(_parm, desc) \
> - __MODULE_INFO(parm, _parm, #_parm ":" desc)
> + __MODULE_INFO(parm, _parm, MODULE_PARAM_PREFIX #_parm ":" desc)
>
> struct kernel_param;
>
> Then some script would look at the parmtype= fields in the built-in.o
> files and complement the list of builtin modules. However, the question
> is whether this is worth it. As far as I understand, the problem is just
> the discrepancy between modules.builtin and /sys/module. In practice, no
> sane tool is going to need to modprobe 'vt' or 'printk', because there
> is no configuration in which these modules would exist.
Indeed, not sure it's worth it. I did the change in kmod so we don't
check /sys/module anymore [1]. If this is problematic for distros then
maybe we add a patch like yours to the kernel so they are also present
in modules.builtin index.
thanks
--
Lucas De Marchi
[1] https://git.kernel.org/cgit/utils/kernel/kmod/kmod.git/commit/?id=fd44a98ae2eb5eb32161088954ab21e58e19dfc4
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