On Thu, Nov 05, 2015 at 10:40:26AM +0100, Jiri Kosina wrote:
> On Thu, 5 Nov 2015, Jiri Kosina wrote:
>
> > > > > +#ifdef CONFIG_DEBUG_SET_MODULE_RONX
> > > > > +static void set_page_attributes(void *start, void *end,
> > > > > + int (*set)(unsigned long start, int num_pages))
> > > > > +{
> > > > > + unsigned long begin_pfn = PFN_DOWN((unsigned long)start);
> > > > > + unsigned long end_pfn = PFN_DOWN((unsigned long)end);
> > > > > +
> > > > > + if (end_pfn > begin_pfn)
> > > > > + set(begin_pfn << PAGE_SHIFT, end_pfn - begin_pfn);
> > > > > +}
> >
> > BTW is there any reason not to make use of the function from module.c
> > which does exactly the same, instead of copy pasting it all around?
> >
> > > > > +static void set_module_ro_rw(struct module *mod)
> > > > > +{
> > > > > + set_page_attributes(mod->module_core,
> > > > > + mod->module_core + mod->core_ro_size,
> > > > > + set_memory_rw);
> > > > > +}
> > > > > +static void set_module_ro_ro(struct module *mod)
> > > >
> > > > Honestly, I find both the function names above horrible and not really
> > > > self-explanatory (especially the _ro_ro variant). At least comment,
> > > > explaining what they are actually doing, or picking up a better name,
> > > > would make the code much more self-explanatory in my eyes.
> > >
> > > Being the patch author, naturally the function names make sense to me.
> >
> > :)
> >
> > > set_module_ro_ro() means "set the module's read-only area to have
> > > read-only permissions."
> > >
> > > Do you have any suggestions for a better name?
> >
> > I'd even say it's superfluous to have the functions at the first place,
> > and just calling set_page_attributes() directly makes the intent clear
> > enough already.
>
> To make my proposal more clear:
>
> - move set_page_attributes() to module.h and provide empty stub for
> !CONFIG_DEBUG_SET_MODULE_RONX case (and probably rename it to something
> like module_set_page_attributes() to avoid namespace conflicts with mm
> code)
>
> - make use of that function both from module.c (where it's already being
> used) and livepatch.c, where it'd be called directly
Ok, I'll use the module.c version of set_page_attributes() and get rid
of the set_module_ro_(ro|rw) functions.
I'd rather keep set_page_attributes() named as it already is, because
there's nothing module-specific about it. It just happens to currently
live in module.c.
--
Josh
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