How does module_init(jpeg_init) get called

[Miles MH Chen]

Hi Michael,

You can use binary utils like nm or objdump to exam your vmlinux.

Linker collects initcall functions and puts them in initcall section.
Kernel can find all initcall functions in initcall section.

Regards,
MH


On Fri, Jan 10, 2014 at 3:00 AM, m silverstri <
michael.j.silverstri at gmail.com> wrote:

> Thanks.  The vmlinx is a binary file, I don't see what you show in
> your response.
>
> I have another question is where does the kernel find these driver
> modules for it to load?
> From the make file, a driver will compile into a .o file?
>
> As an example
>
> $ more Makefile
> s5p-jpeg-objs := jpeg-core.o
> obj-$(CONFIG_VIDEO_SAMSUNG_S5P_JPEG) += s5p-jpeg.o
>
>
>
> On Thu, Jan 9, 2014 at 8:15 AM, Miles MH Chen <orca.chen at gmail.com> wrote:
> > Hello Michael,
> >
> > The module_init call is defined as device_initcall, which is one of
> kernel
> > inicalls.
> > All initcalls are put to initcall section and kernel calls all initcalls
> at
> > boot time.
> >
> > You can check this in your vmlinux:
> >
> > ffffffff81765ed8 T __initcall_start
> > ffffffff81765ed8 T __setup_end
> > ffffffff81765ee0 t __initcall_trace_init_flags_sys_exitearly
> > ffffffff81765ee8 t __initcall_trace_init_flags_sys_enterearly
> > ffffffff81765ef0 t __initcall_init_hw_perf_eventsearly
> > ffffffff81765ef8 t __initcall_register_trigger_all_cpu_backtraceearly
> > ffffffff81765f00 t __initcall_spawn_ksoftirqdearly
> > ffffffff81765f08 t __initcall_init_workqueuesearly
> > ffffffff81765f10 t __initcall_check_cpu_stall_initearly
> > ffffffff81765f18 t __initcall_migration_initearly
> > ...
> >
> > kernel calls do_initcalls in do_basic_setup
> >
> > 783 static void __init do_basic_setup(void)
> > 784 {
> > 785         cpuset_init_smp();
> > 786         usermodehelper_init();
> > 787         shmem_init();
> > 788         driver_init();
> > 789         init_irq_proc();
> > 790         do_ctors();
> > 791         usermodehelper_enable();
> > 792         do_initcalls();
> > 793         random_int_secret_init();
> > 794 }
> >
> > Regards,
> > MH
> >
> >
> >
> > On Thu, Jan 9, 2014 at 10:25 AM, m silverstri
> > <michael.j.silverstri at gmail.com> wrote:
> >>
> >> Hi,
> >>
> >> In a kernel driver code, I see it has 'module_init(jpeg_init)' and
> >> 'module_exit(jpeg_exit)'.  I would like how know how will
> >> jpeg_init(void) gets call during kernel bring up.
> >>
> >> As an example:
> >> static int __init jpeg_init(void)
> >> {
> >> printk(KERN_CRIT "Initialize JPEG driver\n");
> >>
> >> platform_driver_register(&jpeg_driver);
> >>
> >> return 0;
> >> }
> >>
> >> static void __exit jpeg_exit(void)
> >> {
> >> platform_driver_unregister(&jpeg_driver);
> >> }
> >>
> >> module_init(jpeg_init);
> >> module_exit(jpeg_exit);
> >>
> >> Thank you.
> >>
> >> _______________________________________________
> >> Kernelnewbies mailing list
> >> Kernelnewbies at kernelnewbies.org
> >> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
> >
> >
>
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