[PATCH v3 0/5] Improve kernel section protections

[Atish Patra]

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 with non-uefi boot.

---[ 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

Linear mapping with uefi boot.

---[ Linear mapping ]---
0xffffffe000000000-0xffffffe000800000    0x0000000080200000         8M PTE     D A . . X . R V
0xffffffe000800000-0xffffffe000c00000    0x0000000080a00000         4M PTE     D A . . . W R V
0xffffffe000c00000-0xffffffe001200000    0x0000000080e00000         6M PTE     D A . . . . R V
0xffffffe001200000-0xffffffe03e534000    0x0000000081400000   1002704K PTE     D A . . . W R V
0xffffffe03e538000-0xffffffe03e539000    0x00000000be738000         4K PTE     D A . . . W R V
0xffffffe03e53a000-0xffffffe03e53c000    0x00000000be73a000         8K PTE     D A . . . W R V
0xffffffe03e540000-0xffffffe03e541000    0x00000000be740000         4K PTE     D A . . . W R V
0xffffffe03e545000-0xffffffe03e546000    0x00000000be745000         4K PTE     D A . . . W R V
0xffffffe03e549000-0xffffffe03e54a000    0x00000000be749000         4K PTE     D A . . . W R V
0xffffffe03e54b000-0xffffffe03fd6d000    0x00000000be74b000     24712K PTE     D A . . . W R V
0xffffffe03fd6e000-0xffffffe03fdee000    0x00000000bff6e000       512K PTE     D A . . . W R V


Changes from v2->v3:
1. Added few extra comments to clarify rodata permissions.
2. Changed the name of the functions set_memory_default to set_memory_rw_nx.
3. Squashed patch 3&5 together as they depend on each other to allow
   bisectability.
4. Removed redundant arguments in protect_kernel_text_data.

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 (5):
RISC-V: Move __start_kernel to .head.text
RISC-V: Initialize SBI early
RISC-V: Align the .init.text section
RISC-V: Protect all kernel sections including init early
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           | 19 +++++++--
arch/riscv/kernel/vmlinux.lds.S     | 63 +++++++++++++++++------------
arch/riscv/mm/init.c                | 21 +++++++---
arch/riscv/mm/pageattr.c            |  6 +++
7 files changed, 80 insertions(+), 36 deletions(-)

--
2.25.1