[PATCH v4 0/9] Support strict kernel memory permissions for security

From: Zong Li
Date: Tue Apr 07 2020 - 10:47:01 EST


The main purpose of this patch series is changing the kernel mapping permission
, make sure that code is not writeable, data is not executable, and read-only
data is neither writable nor executable.

This patch series also supports the relevant implementations such as
ARCH_HAS_SET_MEMORY, ARCH_HAS_SET_DIRECT_MAP,
ARCH_SUPPORTS_DEBUG_PAGEALLOC and DEBUG_WX.

Changes in v4:
- Use NOKPROBE_SYMBOL instead of __kprobe annotation
- Use text_mutex instead of patch_lock
- Remove 'riscv_' prefix of function name

Changes in v3:
- Fix build error on nommu configuration. We already support nommu on
RISC-V, so we should consider nommu case and test not only rv32/64,
but also nommu.

Changes in v2:
- Use _data to specify the start of data section with write permission.
- Change ftrace patch text implementaion.
- Separate DEBUG_WX patch to another patchset.

Zong Li (9):
riscv: add macro to get instruction length
riscv: introduce interfaces to patch kernel code
riscv: patch code by fixmap mapping
riscv: add ARCH_HAS_SET_MEMORY support
riscv: add ARCH_HAS_SET_DIRECT_MAP support
riscv: add ARCH_SUPPORTS_DEBUG_PAGEALLOC support
riscv: move exception table immediately after RO_DATA
riscv: add alignment for text, rodata and data sections
riscv: add STRICT_KERNEL_RWX support

arch/riscv/Kconfig | 6 +
arch/riscv/include/asm/bug.h | 8 ++
arch/riscv/include/asm/fixmap.h | 2 +
arch/riscv/include/asm/patch.h | 12 ++
arch/riscv/include/asm/set_memory.h | 48 +++++++
arch/riscv/kernel/Makefile | 4 +-
arch/riscv/kernel/ftrace.c | 26 ++--
arch/riscv/kernel/patch.c | 120 ++++++++++++++++++
arch/riscv/kernel/traps.c | 3 +-
arch/riscv/kernel/vmlinux.lds.S | 11 +-
arch/riscv/mm/Makefile | 2 +-
arch/riscv/mm/init.c | 44 +++++++
arch/riscv/mm/pageattr.c | 187 ++++++++++++++++++++++++++++
13 files changed, 458 insertions(+), 15 deletions(-)
create mode 100644 arch/riscv/include/asm/patch.h
create mode 100644 arch/riscv/include/asm/set_memory.h
create mode 100644 arch/riscv/kernel/patch.c
create mode 100644 arch/riscv/mm/pageattr.c

--
2.26.0