[v2,0/4] arm64: refactor the rodata=xxx

Message

Huang Shijie Nov. 26, 2024, 8:56 a.m. UTC

From Documentation/admin-guide/kernel-parameters.txt, we know that:
 rodata=	[KNL,EARLY]
	on	Mark read-only kernel memory as read-only (default).
	off	Leave read-only kernel memory writable for debugging.
	full	Mark read-only kernel memory and aliases as read-only
		[arm64]

So the "rodata=on" is the default.

But the current code does not follow the document, it makes "rodata=full"
as the default.

This patch set follows Will's suggetions:
  - Make our "on" behaviour be what is currently done by "full"
  - Remove RODATA_FULL_DEFAULT_ENABLED
  - Introduce a new option (e.g. "rodata=noalias") which would match the
    current "on" behaviour
  - Update (simplify) the documentation

  https://lists.infradead.org/pipermail/linux-arm-kernel/2024-October/972613.html

v2:
  Follows Will's suggetions.
  Add a new file fine-tuning-tips.rst for the expert users.

v1:
   https://lists.infradead.org/pipermail/linux-arm-kernel/2024-October/971415.html

Huang Shijie (4):
  arm64: make rodata=on behaviour be the original rodata=full
  arm64: remove CONFIG_RODATA_FULL_DEFAULT_ENABLED
  arm64: introduce rodata=noalias
  arm64: add a new document for the fine-tuning tips

 .../admin-guide/kernel-parameters.txt         |  2 +-
 Documentation/arch/arm64/fine-tuning-tips.rst | 23 +++++++++++++++++++
 Documentation/arch/arm64/index.rst            |  1 +
 arch/arm64/Kconfig                            | 14 -----------
 arch/arm64/include/asm/setup.h                |  4 ++--
 arch/arm64/mm/pageattr.c                      |  2 +-
 6 files changed, 28 insertions(+), 18 deletions(-)
 create mode 100644 Documentation/arch/arm64/fine-tuning-tips.rst