Thread (22 messages) 22 messages, 6 authors, 2022-12-16

Re: [PATCH v10 0/9] powerpc/code-patching: Use temporary mm for Radix MMU

From: Michael Ellerman <hidden>
Date: 2022-12-08 12:50:09

On Wed, 9 Nov 2022 15:51:03 +1100, Benjamin Gray wrote:
This is a revision of Chris and Jordan's series to introduce a per-cpu temporary
mm to be used for patching with strict rwx on radix mmus.

v10:	* Don't set poking_init_enabled on boot CPU init failure
	* Remove extern from functions in files touched by this series
	* Changed book3s/32/tlbflush.h stub body from warning to build bug
	* Remove empty hash__ set of functions. Also removed the ones that are
	  just warnings (would have preferred to make them build bugs, but they
	  blocked the build even though it's all inline inside a radix_enabled()
	  if-block).
	  	- It's not possible to use the radix specific necessary TLB flush
		  in code patching, as code-patching.c is compiled even when radix__*
		  functions aren't visible. #ifdefs would be required.
		  The cxl usage required radix__* be visible anyway, so there is no
		  compile issue.
	* Mention cache benefits of struct of patching context variables
	* Don't open-code mm init and teardown. It seems tlb_gather_mmu does
	  the necessary steps to detect page table pages to free, so it should
	  not leak. get_locked_pte() is used over __get_locked_pte() because I
	  don't know what makes the double-underscore function dangerous.

[...]
Patches 1-2 and 4-9 applied to powerpc/next.

[1/9] powerpc: Allow clearing and restoring registers independent of saved breakpoint state
      https://git.kernel.org/powerpc/c/3671f4ebe3eb12e7222e4d7b0f94e85cfe34253a
[2/9] powerpc/code-patching: Use WARN_ON and fix check in poking_init
      https://git.kernel.org/powerpc/c/071c95c1acbd96e76bab8b25b5cad0d71a011f37
[4/9] powerpc/mm: Remove empty hash__ functions
      https://git.kernel.org/powerpc/c/baf1ed24b27db475b38f534953885d0425e2232d
[5/9] cxl: Use radix__flush_all_mm instead of generic flush_all_mm
      https://git.kernel.org/powerpc/c/0f0a0a6091e678b1a75078ecd6b02176f3228dbb
[6/9] powerpc/mm: Remove flush_all_mm, local_flush_all_mm
      https://git.kernel.org/powerpc/c/d34471c9bd5d47ab148dd68817631a4238f755c4
[7/9] powerpc/tlb: Add local flush for page given mm_struct and psize
      https://git.kernel.org/powerpc/c/274d842fa1efd9449e62222c8896e0be11621f1f
[8/9] powerpc/code-patching: Use temporary mm for Radix MMU
      https://git.kernel.org/powerpc/c/c28c15b6d28a776538482101522cbcd9f906b15c
[9/9] powerpc/code-patching: Consolidate and cache per-cpu patching context
      https://git.kernel.org/powerpc/c/2f228ee1ade5d8d1f26cf94863a36c5693023c58

cheers
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