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