[PATCH 0/7] introduce __ro_mostly_after_init section marker

[Hoeun Ryu]

 After `__ro_after_init` marker is included in kernel, many kernel data
objects can be read-only-after-init. But there are many other places that
would be good to read-only-after-init but `__ro_after_init` can not be simply
applicable to them because they should be writable at some points, which are
during module_init/exit or dynamic de/registration for a specific subsystem.
 `__ro_mostly_after_init` is basically the same to `__ro_after_init`. The
section is mapped as read-only after kernel init. The different thing is
this section is temporarily mapped as read-write during module_init/exit and
de/registration of a subsystem using set_ro_mostly_after_init_rw/ro pair.

- Tested only on arm64.

Description:
  0001 patch is `__ro_mostly_after_init` itself.
  0002 patch is to add set_ro_mostly_after_init_rw/ro pair using
    set_memory_rw/ro.
  0003 patch is to make the section read-write in module_init/exit.
  0004 patch is an example for dynamic init/deinit of a subsystem.
  0005 patch is an example for __ro_mostly_after_init section modified during
    module_init/exit.
  0006/0007 patches are fixes for arm64 kernel mapping.

Hoeun Ryu (7):
  arch: add __ro_mostly_after_init section marker
  init: add set_ro_mostly_after_init_rw/ro function
  module: modify memory attrs for __ro_mostly_after_init during
    module_init/exit
  selinux: mark __ro_mostly_after_init for selinux_hooks/selinux_nf_ops
  cpu: mark ro_mostly_after_init for cpuhp_ap/bp_states
  arm64: add __map_kernel_segment to accept additional vm flags
  arm64: map seperately rodata sections for __ro_mostly_after_init
    section

 arch/arm64/mm/mmu.c               | 44 ++++++++++++++++++++++++++++++++-------
 include/asm-generic/sections.h    |  1 +
 include/asm-generic/vmlinux.lds.h | 10 +++++++++
 include/linux/cache.h             | 11 ++++++++++
 include/linux/init.h              |  6 ++++++
 init/main.c                       | 24 +++++++++++++++++++++
 kernel/cpu.c                      |  4 ++--
 kernel/module.c                   | 10 +++++++--
 security/selinux/hooks.c          |  8 +++++--
 9 files changed, 105 insertions(+), 13 deletions(-)

-- 
2.7.4