[PATCH v2 0/6] Improve kernel section protections

Atish Patra
2020-10-26T23:03:27Z

This series aims at improving kernel permissions by doing following things.

1. Protect kernel sections early instead of after /init.
2. Protect .init.text & .init.data sections with appropriate permissions.
3. Move dynamic relocation section to _init.
4. Moved .init sections after .text. This is what most of the other archs
are also doing.

After applying this patch, here are the linear mapped sections.

---[ Linear mapping ]---
0xffffffe000000000-0xffffffe000800000 0x0000000080200000 8M PMD D A . . X . R V
0xffffffe000800000-0xffffffe000c00000 0x0000000080a00000 4M PMD D A . . . W R V
0xffffffe000c00000-0xffffffe001200000 0x0000000080e00000 6M PMD D A . . . . R V
0xffffffe001200000-0xffffffe03fe00000 0x0000000081400000 1004M PMD D A . . . W R V

Changes from v1->v2:
1. .init.text section is aligned with SECTION_ALIGN.
2. .init.text is moved to below of .text so that .head.text & .text are in
one section.
3. We don't need Guo's fix for static object issue.
4. Rebased on 5.10-rc1.

Atish Patra (6):
RISC-V: Move __start_kernel to .head.text
RISC-V: Initialize SBI early
RISC-V: Enforce protections for kernel sections early
RISC-V: Align the .init.text section
RISC-V: Protect .init.text & .init.data
RISC-V: Move dynamic relocation section under __init

arch/riscv/include/asm/sections.h | 2 +
arch/riscv/include/asm/set_memory.h | 4 ++
arch/riscv/kernel/head.S | 1 -
arch/riscv/kernel/setup.c | 18 +++++++--
arch/riscv/kernel/vmlinux.lds.S | 63 +++++++++++++++++------------
arch/riscv/mm/init.c | 19 +++++++--
arch/riscv/mm/pageattr.c | 6 +++
7 files changed, 79 insertions(+), 34 deletions(-)

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2.25.1