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SubjectRe: [PATCH] Show version information for built-in modules in sysfs
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On Thu, 16 Dec 2010 08:30:19 am Dmitry Torokhov wrote:
> Currently only drivers that are built as modules have their versions
> shown in /sys/module/<module_name>/version, but this information might
> also be useful for built-in drivers as well. This especially important
> for drivers that do not define any parameters - such drivers, if
> built-in, are completely invisible from userspace.
>
> This patch changes MODULE_VERSION() macro so that in case when we are
> compiling built-in module, version information is stored in a separate
> section. Kernel then uses this data to create 'version' sysfs attribute
> in the same fashion it creates attributes for module parameters.
>
> Signed-off-by: Dmitry Torokhov <dtor@vmware.com>
> ---
>
> This change is driven by our desire to detect whether vmw_balloon driver
> is built-in into the kernel when we installing our tool package in the
> guest and avoid installing our own version of the driver.
>
> Since vmw_balloon does not have any module parameter nor registers any
> driver core devices, without this patch it is completely invisible from
> userspace when built into the kernel.
>
> Thanks,
> Dmitry
>
> include/asm-generic/vmlinux.lds.h | 7 ++++
> include/linux/module.h | 27 +++++++++++++++
> kernel/params.c | 65 ++++++++++++++++++++++++++++++------
> 3 files changed, 88 insertions(+), 11 deletions(-)
>
> diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
> index bd69d79..0d83dd1 100644
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@ -355,6 +355,13 @@
> VMLINUX_SYMBOL(__start___param) = .; \
> *(__param) \
> VMLINUX_SYMBOL(__stop___param) = .; \
> + } \
> + \
> + /* Built-in module versions. */ \
> + __modver : AT(ADDR(__modver) - LOAD_OFFSET) { \
> + VMLINUX_SYMBOL(__start___modver) = .; \
> + *(__modver) \
> + VMLINUX_SYMBOL(__stop___modver) = .; \
> . = ALIGN((align)); \
> VMLINUX_SYMBOL(__end_rodata) = .; \
> } \
> diff --git a/include/linux/module.h b/include/linux/module.h
> index 7575bbb..f74ddda 100644
> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -58,6 +58,12 @@ struct module_attribute {
> void (*free)(struct module *);
> };
>
> +struct module_version_attribute {
> + struct module_attribute mattr;
> + const char *module_name;
> + const char *version;
> +};
> +
> struct module_kobject
> {
> struct kobject kobj;
> @@ -161,7 +167,28 @@ extern struct module __this_module;
> Using this automatically adds a checksum of the .c files and the
> local headers in "srcversion".
> */
> +
> +#ifdef MODULE
> #define MODULE_VERSION(_version) MODULE_INFO(version, _version)
> +#else
> +#define MODULE_VERSION(_version) \
> + extern ssize_t __modver_version_show(struct module_attribute *, \
> + struct module *, char *); \
> + static struct module_version_attribute __modver_version_attr \
> + __used \
> + __attribute__ ((unused,__section__ ("__modver"),aligned(sizeof(void *)))) \

__used and unused seems overkill, and confused.

Removed unused.

Cheers,
Rusty.


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