On Fri, Aug 23, 2013 at 05:13:31PM +0200, Peter Oberparleiter wrote:
> On 23.08.2013 10:39, Frantisek Hrbata wrote:
> > This adds the .init_array section as yet another section with constructors. This
> > is needed because gcc is adding __gcov_init calls to .init_array.
> >
> > Signed-off-by: Frantisek Hrbata <fhrbata@xxxxxxxxxx>
> > ---
> > include/asm-generic/vmlinux.lds.h | 1 +
> > include/linux/module.h | 2 ++
> > kernel/module.c | 6 ++++++
> > 3 files changed, 9 insertions(+)
> >
> > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
> > index 69732d2..c55d8d9 100644
> > --- a/include/asm-generic/vmlinux.lds.h
> > +++ b/include/asm-generic/vmlinux.lds.h
> > @@ -468,6 +468,7 @@
> > #define KERNEL_CTORS() . = ALIGN(8); \
> > VMLINUX_SYMBOL(__ctors_start) = .; \
> > *(.ctors) \
> > + *(.init_array) \
>
> This is exactly how I (would) have done it.
>
> > VMLINUX_SYMBOL(__ctors_end) = .;
> > #else
> > #define KERNEL_CTORS()
> > diff --git a/include/linux/module.h b/include/linux/module.h
> > index 46f1ea0..89ff829 100644
> > --- a/include/linux/module.h
> > +++ b/include/linux/module.h
> > @@ -374,6 +374,8 @@ struct module
> > /* Constructor functions. */
> > ctor_fn_t *ctors;
> > unsigned int num_ctors;
> > + ctor_fn_t *init_array;
> > + unsigned int num_init_array;
>
> I think it would be safe to re-use the ctors-related fields here. Each GCC
> version will only ever create either of .ctors or .init_array, but never
> both.
> The only case where separate fields would be required, would be when
> linking a kernel module from multiple object files compiled with different
> versions of GCC.
Ah ok, I was not aware of this.
>
> > #endif
> > };
> > #ifndef MODULE_ARCH_INIT
> > diff --git a/kernel/module.c b/kernel/module.c
> > index 2069158..581ae89 100644
> > --- a/kernel/module.c
> > +++ b/kernel/module.c
> > @@ -2760,6 +2760,9 @@ static void find_module_sections(struct module *mod, struct load_info *info)
> > #ifdef CONFIG_CONSTRUCTORS
> > mod->ctors = section_objs(info, ".ctors",
> > sizeof(*mod->ctors), &mod->num_ctors);
>
> When reusing mod->ctors, you could check for mod->ctors == NULL here and
> fill in the values from section_objs(".init_array").
Yes, in the case that we only have .ctors or .init_array section, this sounds
as the right approach.
>
> > + mod->init_array = section_objs(info, ".init_array",
> > + sizeof(*mod->init_array),
> > + &mod->num_init_array);
> > #endif
> >
> > #ifdef CONFIG_TRACEPOINTS
> > @@ -3024,6 +3027,9 @@ static void do_mod_ctors(struct module *mod)
> >
> > for (i = 0; i < mod->num_ctors; i++)
> > mod->ctors[i]();
> > +
> > + for (i = 0; i < mod->num_init_array; i++)
> > + mod->init_array[i]();
> > #endif
> > }
> >
>
> --
> Peter Oberparleiter
> Linux on System z Development - IBM Germany
>
--
Frantisek Hrbata
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