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Date: Tue, 21 Dec 2010 17:17:12 -0800 From: Dmitry Torokhov <dtor@...are.com> To: Rusty Russell <rusty@...tcorp.com.au> Cc: LKML <linux-kernel@...r.kernel.org> Subject: Re: [PATCH] Show version information for built-in modules in sysfs 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@...are.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? Thanks, Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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