powerpc/Kconfig: Enable STRICT_KERNEL_RWX for some configs

All code that patches kernel text has been moved over to using
patch_instruction() and patch_instruction() is able to cope with the
kernel text being read only.

The linker script has been updated to ensure the read only data ends
on a large page boundary, so it and the preceding kernel text can be
marked R_X. We also have implementations of mark_rodata_ro() for Hash
and Radix MMU modes.

There are some corner-cases missing when the kernel is built
relocatable, so for now make it depend on !RELOCATABLE.

There's also a temporary workaround to depend on !HIBERNATION to avoid
a build failure, that will be removed once we've merged with the PM
tree.

Signed-off-by: Balbir Singh <bsingharora@gmail.com>
[mpe: Make it depend on !RELOCATABLE, munge change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Balbir Singh 2017-06-29 03:04:11 +10:00 committed by Michael Ellerman
parent 7614ff3272
commit 1e0fc9d1eb

View File

@ -164,6 +164,8 @@ config PPC
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_TRACEHOOK
select ARCH_HAS_STRICT_KERNEL_RWX if (PPC_BOOK3S_64 && !RELOCATABLE && !HIBERNATION)
select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
select HAVE_CBPF_JIT if !PPC64
select HAVE_CONTEXT_TRACKING if PPC64
select HAVE_DEBUG_KMEMLEAK