[PATCH v7 0/2] Map the kernel with correct permissions the first time

From: Alexandre Ghiti
Date: Tue Jun 22 2021 - 04:21:44 EST

The kernel permissions are fixed after the kernel page table is created:
avoid that by mapping the kernel 'correctly' the first time.

Patch 1 introduces a new helper to set kernel mapping permissions while
avoiding all the casts when using set_memory_* API.

Patch 2 is the bulk of this work and deals with mapping the kernel with
the right permissions.

Changes in v7:
* Split long lines and reintroduce parameters names of set_kernel_memory
callback, as suggested by Christoph
* Make set_kernel_memory __always_inline as suggested by Christoph
* Change 64b spelling into 64-bit, as suggested by Christoph

Changes in v6:
* load_sz was placed in init section but is now used in kernel address
conversions macros, so remove this attribute.

Changes in v5:
* Remove non-relevant commits to this patchset that raised issues
* Make load_sz non-static as it is used in kernel address conversions
* Rebased on top for-next

Changes in v4:
* Add patch 1 as noted by Jisheng
* Changes patch 2 title as suggested by Anup
* Add Reviewed-by from Anup

Changes in v3:
* Add a patch that factorizes kernel address conversions
* Add a helper called set_kernel_memory in its own patch, as suggested by
* Prefer IS_ENABLED over #ifdef, as suggested by Christoph
* Split overly long lines, as suggested by Christoph
* Simplify kernel mapping by mapping ALL text as readonly and taking advantage
of already present code that enables write for init text before

Changes in v2:
* Rebased on top of for-next (and "riscv: mm: fix build errors caused by
* Get rid of protect_kernel_linear_mapping_text_rodata as suggested by
* Improve code in general compared to previous RFC

Alexandre Ghiti (2):
riscv: Introduce set_kernel_memory helper
riscv: Map the kernel with correct permissions the first time

arch/riscv/include/asm/page.h | 13 +++-
arch/riscv/include/asm/sections.h | 17 +++++
arch/riscv/include/asm/set_memory.h | 16 ++--
arch/riscv/kernel/setup.c | 12 +--
arch/riscv/mm/init.c | 112 ++++++++++++----------------
arch/riscv/mm/pageattr.c | 11 +++
6 files changed, 100 insertions(+), 81 deletions(-)