Messages in this thread | | | From | Kees Cook <> | Date | Tue, 7 Jun 2016 08:49:14 -0700 | Subject | Re: [PATCH 0/2] Proper ro_after_init implementation on s390 |
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On Tue, Jun 7, 2016 at 5:06 AM, Heiko Carstens <heiko.carstens@de.ibm.com> wrote: > These two patches allow a proper ro_after_init implementation on s390. > > The current implementation maps __ro_after_init to __read_mostly, > which means that ro_after_init data won't be write protected at all. > > Reason for this is that s390 write protects rodata very early (before > init calls) and therefore adding ro_after_init data to rodata would > lead to crashes. > > Since I don't want to mark the page table entries much later read-only > on s390 just to make this work, allow an architecture specific > handling which can be used to move the ro_after_init data to a > different place which can be marked read-only later when > mark_rodata_ro gets executed. > > Note: these patches require the s390 kernel page table splitting > support which currently is only available at > > git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git features > > (included in linux-next) > > Therefore, if we can agree on this solution I'd like to add these > patches to the s390 tree, so it can be merged during the next merge > window. > > Heiko Carstens (2): > vmlinux.lds.h: allow arch specific handling of ro_after_init data section > s390/mm: add proper __ro_after_init support > > arch/s390/include/asm/cache.h | 3 --- > arch/s390/include/asm/sections.h | 1 + > arch/s390/kernel/vmlinux.lds.S | 12 +++++++++++- > arch/s390/mm/init.c | 7 ++++--- > arch/s390/mm/vmem.c | 7 +++---- > include/asm-generic/vmlinux.lds.h | 10 +++++++++- > 6 files changed, 28 insertions(+), 12 deletions(-)
Awesome! This looks great to me! Have you had a chance to look through any of the arch/s390/ __init code for variables that should be marked __ro_after_init?
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
-- Kees Cook Chrome OS & Brillo Security
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