[PATCH v3 0/3] riscv: Map the kernel with correct permissions the first time

From: Alexandre Ghiti
Date: Thu Jun 03 2021 - 04:27:59 EST

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

Patch 1 is a cleanup patch on which the next patches are based on, not
necessary for this patchset though.

Patch 2 introduces a new helper to set kernel mapping permissions while
avoiding all the casts when using set_memory_* API.

Patch 3 is the bulk of this work and deals with mapping the kernel with
the right permissions.

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 (3):
riscv: Factorize xip and !xip kernel address conversion macros
riscv: Introduce set_kernel_memory helper
riscv: Map the kernel with correct permissions the first time

arch/riscv/include/asm/page.h | 27 ++++----
arch/riscv/include/asm/pgtable.h | 2 +
arch/riscv/include/asm/sections.h | 17 +++++
arch/riscv/include/asm/set_memory.h | 13 ++--
arch/riscv/kernel/setup.c | 11 +--
arch/riscv/mm/init.c | 102 ++++++++++++----------------
arch/riscv/mm/pageattr.c | 10 +++
7 files changed, 95 insertions(+), 87 deletions(-)