[PATCH v2 0/5] Allocate module text and data separately

From: Christophe Leroy
Date: Thu Jan 27 2022 - 06:28:01 EST


This series allow architectures to request having modules data in
vmalloc area instead of module area.

This is required on powerpc book3s/32 in order to set data non
executable, because it is not possible to set executability on page
basis, this is done per 256 Mbytes segments. The module area has exec
right, vmalloc area has noexec. Without this change module data
remains executable regardless of CONFIG_STRICT_MODULES_RWX.

This can also be useful on other powerpc/32 in order to maximize the
chance of code being close enough to kernel core to avoid branch
trampolines.

Changes in v2:
- Dropped first two patches which are not necessary. They may be added back later as a follow-up series.
- Fixed the printks in GDB

Christophe Leroy (5):
modules: Always have struct mod_tree_root
modules: Prepare for handling several RB trees
modules: Introduce data_layout
modules: Add CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
powerpc: Select ARCH_WANTS_MODULES_DATA_IN_VMALLOC on book3s/32 and
8xx

arch/Kconfig | 6 ++
arch/powerpc/Kconfig | 1 +
include/linux/module.h | 8 ++
kernel/debug/kdb/kdb_main.c | 10 +-
kernel/module.c | 193 +++++++++++++++++++++++++-----------
5 files changed, 156 insertions(+), 62 deletions(-)

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2.33.1