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SubjectRe: [PATCH v3 0/9] Support strict kernel memory permissions for security
Hi Zong,

On Tue, 10 Mar 2020 00:55:35 +0800
Zong Li <zong.li@sifive.com> wrote:

> 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.

The order of the patches seems a bit strange. Since the first 7 patches
makes kernel read-only, at that point ftrace is broken and it is fixed
by the last 2 patches. That is not bisect-friendly. Can you move the
last 2 patches to the top?

Thank you,

>
> 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 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
> riscv: add macro to get instruction length
> riscv: introduce interfaces to patch kernel code
> riscv: patch code by fixmap mapping
>
> 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 | 13 +-
> 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, 445 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
>
> --
> 2.25.1
>


--
Masami Hiramatsu <mhiramat@kernel.org>

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