+ mm-enable-mmu_gather_rcu_table_free-for-arc-microblaze-xtensa.patch added to mm-new branch

+ mm-enable-mmu_gather_rcu_table_free-for-arc-microblaze-xtensa.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm: enable MMU_GATHER_RCU_TABLE_FREE for arc, microblaze, xtensa
has been added to the -mm mm-new branch.  Its filename is
     mm-enable-mmu_gather_rcu_table_free-for-arc-microblaze-xtensa.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-enable-mmu_gather_rcu_table_free-for-arc-microblaze-xtensa.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

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and is updated there most days

------------------------------------------------------
From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Subject: mm: enable MMU_GATHER_RCU_TABLE_FREE for arc, microblaze, xtensa
Date: Tue, 08 Sep 2026 13:32:14 +0100

Each of these architectures directly free page tables without routing
these changes through tlb_remove_ptdesc().

The use of tlb_remove_ptdesc() is required for
CONFIG_MMU_GATHER_RCU_TABLE_FREE to correctly free page tables under RCU,
so simply update these architectures to use these functions.

Since none of the architectures share page tables or do anything unusual,
nothing complicated is required here.

Therefore this is simply a mechanical change - convert __pud_free_tlb(),
__pmd_free_tlb() and __pte_free_tlb() to use tlb_remove_ptdesc() as
required.

At the point this is in place, all mmu_gather page table freeing is
performed under RCU, and thus MMU_GATHER_RCU_TABLE_FREE is selected for
each architecture.

Note that CONFIG_MMU_GATHER_RCU_TABLE_FREE is dependent on CONFIG_MMU for
xtensa to reflect the fact that nommu does not implement page table
gathering.

This forms part of an overall effort to switch every architecture to this
mode.

Link: https://lore.kernel.org/20260908-rcu-pagetable-freeing-v2-5-1f60b64e878e@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@kernel.org>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Zankel <chris@zankel.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Bottomley <james.bottomley@HansenPartnership.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Kiryl Shutsemau <kas@kernel.org>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/arc/Kconfig                      |    1 +
 arch/arc/include/asm/pgalloc.h        |    6 +++---
 arch/microblaze/Kconfig               |    1 +
 arch/microblaze/include/asm/pgalloc.h |    2 +-
 arch/xtensa/Kconfig                   |    1 +
 arch/xtensa/include/asm/tlb.h         |    2 +-
 6 files changed, 8 insertions(+), 5 deletions(-)

--- a/arch/arc/include/asm/pgalloc.h~mm-enable-mmu_gather_rcu_table_free-for-arc-microblaze-xtensa
+++ a/arch/arc/include/asm/pgalloc.h
@@ -72,7 +72,7 @@ static inline void p4d_populate(struct m
 	set_p4d(p4dp, __p4d((unsigned long)pudp));
 }
 
-#define __pud_free_tlb(tlb, pmd, addr)  pud_free((tlb)->mm, pmd)
+#define __pud_free_tlb(tlb, pmd, addr)  tlb_remove_ptdesc((tlb), virt_to_ptdesc(pmd))
 
 #endif
 
@@ -83,10 +83,10 @@ static inline void pud_populate(struct m
 	set_pud(pudp, __pud((unsigned long)pmdp));
 }
 
-#define __pmd_free_tlb(tlb, pmd, addr)  pmd_free((tlb)->mm, pmd)
+#define __pmd_free_tlb(tlb, pmd, addr)  tlb_remove_ptdesc((tlb), virt_to_ptdesc(pmd))
 
 #endif
 
-#define __pte_free_tlb(tlb, pte, addr)  pte_free((tlb)->mm, pte)
+#define __pte_free_tlb(tlb, pte, addr)  tlb_remove_ptdesc((tlb), page_ptdesc(pte))
 
 #endif /* _ASM_ARC_PGALLOC_H */
--- a/arch/arc/Kconfig~mm-enable-mmu_gather_rcu_table_free-for-arc-microblaze-xtensa
+++ a/arch/arc/Kconfig
@@ -47,6 +47,7 @@ config ARC
 	select HAVE_SYSCALL_TRACEPOINTS
 	select IRQ_DOMAIN
 	select LOCK_MM_AND_FIND_VMA
+	select MMU_GATHER_RCU_TABLE_FREE
 	select MODULES_USE_ELF_RELA
 	select OF
 	select OF_EARLY_FLATTREE
--- a/arch/microblaze/include/asm/pgalloc.h~mm-enable-mmu_gather_rcu_table_free-for-arc-microblaze-xtensa
+++ a/arch/microblaze/include/asm/pgalloc.h
@@ -25,7 +25,7 @@ extern void __bad_pte(pmd_t *pmd);
 
 extern pte_t *pte_alloc_one_kernel(struct mm_struct *mm);
 
-#define __pte_free_tlb(tlb, pte, addr)	pte_free((tlb)->mm, (pte))
+#define __pte_free_tlb(tlb, pte, addr)	tlb_remove_ptdesc((tlb), page_ptdesc(pte))
 
 #define pmd_populate(mm, pmd, pte) \
 			(pmd_val(*(pmd)) = (unsigned long)page_address(pte))
--- a/arch/microblaze/Kconfig~mm-enable-mmu_gather_rcu_table_free-for-arc-microblaze-xtensa
+++ a/arch/microblaze/Kconfig
@@ -41,6 +41,7 @@ config MICROBLAZE
 	select PCI_SYSCALL if PCI
 	select CPU_NO_EFFICIENT_FFS
 	select MMU_GATHER_NO_RANGE
+	select MMU_GATHER_RCU_TABLE_FREE
 	select SPARSE_IRQ
 	select ZONE_DMA
 	select TRACE_IRQFLAGS_SUPPORT
--- a/arch/xtensa/include/asm/tlb.h~mm-enable-mmu_gather_rcu_table_free-for-arc-microblaze-xtensa
+++ a/arch/xtensa/include/asm/tlb.h
@@ -16,7 +16,7 @@
 
 #include <asm-generic/tlb.h>
 
-#define __pte_free_tlb(tlb, pte, address)	pte_free((tlb)->mm, pte)
+#define __pte_free_tlb(tlb, pte, address)	tlb_remove_ptdesc((tlb), page_ptdesc(pte))
 
 void check_tlb_sanity(void);
 
--- a/arch/xtensa/Kconfig~mm-enable-mmu_gather_rcu_table_free-for-arc-microblaze-xtensa
+++ a/arch/xtensa/Kconfig
@@ -55,6 +55,7 @@ config XTENSA
 	select HAVE_VIRT_CPU_ACCOUNTING_GEN
 	select IRQ_DOMAIN
 	select LOCK_MM_AND_FIND_VMA
+	select MMU_GATHER_RCU_TABLE_FREE if MMU
 	select MODULES_USE_ELF_RELA
 	select PERF_USE_VMALLOC
 	select TRACE_IRQFLAGS_SUPPORT
_

Patches currently in -mm which might be from ljs@kernel.org are

mm-vma-correctly-unaccount-on-mmap_prepare-failure.patch
mm-vmpressure-remove-window-size-todo.patch
tools-testing-selftests-mm-add-missing-gitignore-entries.patch
mm-move-drivers-char-memc-to-mm-char-memc.patch
mm-implement-file_is_dev_zero-to-uniquely-identify-dev-zero.patch
mm-vma-only-permit-map_private-dev-zero-to-be-mapped-anonymous.patch
mm-vma-make-map_private-mapped-dev-zero-mappings-truly-anonymous.patch
tools-testing-vma-add-test-to-assert-map_private-dev-zero-is-anon.patch
tools-testing-selftests-mm-add-map_private-dev-zero-merge-tests.patch
mm-madvise-swap-in-cowd-map_private-file-mappings-on-madv_willneed.patch
mm-huge_memory-zap-deposited-page-tables-after-an-rcu-grace-period.patch
mm-enable-mmu_gather_rcu_table_free-for-most-2-level-architectures.patch
mm-enable-mmu_gather_rcu_table_free-for-mmu-riscv.patch
mm-enable-mmu_gather_rcu_table_free-for-mmu-arm.patch
mm-enable-mmu_gather_rcu_table_free-for-arc-microblaze-xtensa.patch
mm-enable-mmu_gather_rcu_table_free-for-sparc64.patch
mm-enable-mmu_gather_rcu_table_free-for-m68k-coldfire.patch
mm-enable-mmu_gather_rcu_table_free-for-sh-x2.patch
mm-enable-mmu_gather_rcu_table_free-for-m68k-motorola.patch
mm-enable-mmu_gather_rcu_table_free-for-sparc32.patch
mm-make-userland-page-table-freeing-rcu-safe.patch
mm-change-the-contract-for-free_pgtables-update-docs.patch