lkml.org 
[lkml]   [2010]   [Dec]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH] Show version information for built-in modules in sysfs
Date
On Wed, 22 Dec 2010 11:47:12 am Dmitry Torokhov wrote:
> On Tue, Dec 21, 2010 at 05:02:40PM -0800, Rusty Russell wrote:
> > 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.
> >
>
> Must admit that I copied used/unused verbatim from linux/moduleparam.h:
>
> /* This is the fundamental function for registering boot/module
> parameters. */
> #define __module_param_call(prefix, name, ops, arg, isbool, perm) \
> /* Default value instead of permissions? */ \
> static int __param_perm_check_##name __attribute__((unused)) = \
> BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2)) \
> + BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN); \
> static const char __param_str_##name[] = prefix #name; \
> static struct kernel_param __moduleparam_const __param_##name \
> __used \
> __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
> = { __param_str_##name, ops, perm, isbool ? KPARAM_ISBOOL : 0, \
> { arg } }
>
>
> So should it be removed from here as well?

I think so, but (as always!) check git blame.

Patch welcome!
Rusty.


\
 
 \ /
  Last update: 2010-12-22 02:51    [from the cache]
©2003-2011 Jasper Spaans