+ powerpc-mm-support-page-table-check.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: powerpc/mm: support page table check
has been added to the -mm mm-new branch.  Its filename is
     powerpc-mm-support-page-table-check.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/powerpc-mm-support-page-table-check.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

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days

------------------------------------------------------
From: Rohan McLure <rmclure@linux.ibm.com>
Subject: powerpc/mm: support page table check
Date: Fri, 19 Dec 2025 04:09:44 +1100

On creation and clearing of a page table mapping, instrument such calls by
invoking page_table_check_pte_set and page_table_check_pte_clear
respectively.  These calls serve as a sanity check against illegal
mappings.

Enable ARCH_SUPPORTS_PAGE_TABLE_CHECK on powerpc, except when HUGETLB_PAGE
is enabled (powerpc has some weirdness in how it implements
set_huge_pte_at(), which may require some further work).

See also:

riscv support in commit 3fee229a8eb9 ("riscv/mm: enable
ARCH_SUPPORTS_PAGE_TABLE_CHECK")
arm64 in commit 42b2547137f5 ("arm64/mm: enable
ARCH_SUPPORTS_PAGE_TABLE_CHECK")
x86_64 in commit d283d422c6c4 ("x86: mm: add x86_64 support for page table
check")

[ajd@linux.ibm.com: rebase, add additional instrumentation, misc fixes]
Link: https://lkml.kernel.org/r/20251219-pgtable_check_v18rebase-v18-12-755bc151a50b@linux.ibm.com
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Acked-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Guo Weikang <guoweikang.kernel@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Thomas Huth <thuth@redhat.com>
Cc: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/powerpc/Kconfig                         |    1 
 arch/powerpc/include/asm/book3s/32/pgtable.h |    7 ++
 arch/powerpc/include/asm/book3s/64/pgtable.h |   45 +++++++++++++----
 arch/powerpc/include/asm/nohash/pgtable.h    |    8 ++-
 arch/powerpc/mm/book3s64/hash_pgtable.c      |    4 +
 arch/powerpc/mm/book3s64/pgtable.c           |   19 ++++---
 arch/powerpc/mm/book3s64/radix_pgtable.c     |    3 +
 arch/powerpc/mm/pgtable.c                    |    4 +
 8 files changed, 73 insertions(+), 18 deletions(-)

--- a/arch/powerpc/include/asm/book3s/32/pgtable.h~powerpc-mm-support-page-table-check
+++ a/arch/powerpc/include/asm/book3s/32/pgtable.h
@@ -202,6 +202,7 @@ void unmap_kernel_page(unsigned long va)
 #ifndef __ASSEMBLER__
 #include <linux/sched.h>
 #include <linux/threads.h>
+#include <linux/page_table_check.h>
 
 /* Bits to mask out from a PGD to get to the PUD page */
 #define PGD_MASKED_BITS		0
@@ -315,7 +316,11 @@ static inline int __ptep_test_and_clear_
 static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
 				       pte_t *ptep)
 {
-	return __pte(pte_update(mm, addr, ptep, ~_PAGE_HASHPTE, 0, 0));
+	pte_t old_pte = __pte(pte_update(mm, addr, ptep, ~_PAGE_HASHPTE, 0, 0));
+
+	page_table_check_pte_clear(mm, addr, old_pte);
+
+	return old_pte;
 }
 
 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h~powerpc-mm-support-page-table-check
+++ a/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -144,6 +144,8 @@
 #define PAGE_KERNEL_ROX	__pgprot(_PAGE_BASE | _PAGE_KERNEL_ROX)
 
 #ifndef __ASSEMBLER__
+#include <linux/page_table_check.h>
+
 /*
  * page table defines
  */
@@ -416,8 +418,11 @@ static inline void huge_ptep_set_wrprote
 static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
 				       unsigned long addr, pte_t *ptep)
 {
-	unsigned long old = pte_update(mm, addr, ptep, ~0UL, 0, 0);
-	return __pte(old);
+	pte_t old_pte = __pte(pte_update(mm, addr, ptep, ~0UL, 0, 0));
+
+	page_table_check_pte_clear(mm, addr, old_pte);
+
+	return old_pte;
 }
 
 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
@@ -426,11 +431,16 @@ static inline pte_t ptep_get_and_clear_f
 					    pte_t *ptep, int full)
 {
 	if (full && radix_enabled()) {
+		pte_t old_pte;
+
 		/*
 		 * We know that this is a full mm pte clear and
 		 * hence can be sure there is no parallel set_pte.
 		 */
-		return radix__ptep_get_and_clear_full(mm, addr, ptep, full);
+		old_pte = radix__ptep_get_and_clear_full(mm, addr, ptep, full);
+		page_table_check_pte_clear(mm, addr, old_pte);
+
+		return old_pte;
 	}
 	return ptep_get_and_clear(mm, addr, ptep);
 }
@@ -1301,19 +1311,34 @@ extern int pudp_test_and_clear_young(str
 static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
 					    unsigned long addr, pmd_t *pmdp)
 {
-	if (radix_enabled())
-		return radix__pmdp_huge_get_and_clear(mm, addr, pmdp);
-	return hash__pmdp_huge_get_and_clear(mm, addr, pmdp);
+	pmd_t old_pmd;
+
+	if (radix_enabled()) {
+		old_pmd = radix__pmdp_huge_get_and_clear(mm, addr, pmdp);
+	} else {
+		old_pmd = hash__pmdp_huge_get_and_clear(mm, addr, pmdp);
+	}
+
+	page_table_check_pmd_clear(mm, addr, old_pmd);
+
+	return old_pmd;
 }
 
 #define __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR
 static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm,
 					    unsigned long addr, pud_t *pudp)
 {
-	if (radix_enabled())
-		return radix__pudp_huge_get_and_clear(mm, addr, pudp);
-	BUG();
-	return *pudp;
+	pud_t old_pud;
+
+	if (radix_enabled()) {
+		old_pud = radix__pudp_huge_get_and_clear(mm, addr, pudp);
+	} else {
+		BUG();
+	}
+
+	page_table_check_pud_clear(mm, addr, old_pud);
+
+	return old_pud;
 }
 
 static inline pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
--- a/arch/powerpc/include/asm/nohash/pgtable.h~powerpc-mm-support-page-table-check
+++ a/arch/powerpc/include/asm/nohash/pgtable.h
@@ -29,6 +29,8 @@ static inline pte_basic_t pte_update(str
 
 #ifndef __ASSEMBLER__
 
+#include <linux/page_table_check.h>
+
 extern int icache_44x_need_flush;
 
 #ifndef pte_huge_size
@@ -122,7 +124,11 @@ static inline void ptep_set_wrprotect(st
 static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
 				       pte_t *ptep)
 {
-	return __pte(pte_update(mm, addr, ptep, ~0UL, 0, 0));
+	pte_t old_pte = __pte(pte_update(mm, addr, ptep, ~0UL, 0, 0));
+
+	page_table_check_pte_clear(mm, addr, old_pte);
+
+	return old_pte;
 }
 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
 
--- a/arch/powerpc/Kconfig~powerpc-mm-support-page-table-check
+++ a/arch/powerpc/Kconfig
@@ -172,6 +172,7 @@ config PPC
 	select ARCH_STACKWALK
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_SUPPORTS_DEBUG_PAGEALLOC	if PPC_BOOK3S || PPC_8xx
+	select ARCH_SUPPORTS_PAGE_TABLE_CHECK	if !HUGETLB_PAGE
 	select ARCH_SUPPORTS_SCHED_MC		if SMP
 	select ARCH_SUPPORTS_SCHED_SMT		if PPC64 && SMP
 	select SCHED_MC				if ARCH_SUPPORTS_SCHED_MC
--- a/arch/powerpc/mm/book3s64/hash_pgtable.c~powerpc-mm-support-page-table-check
+++ a/arch/powerpc/mm/book3s64/hash_pgtable.c
@@ -8,6 +8,7 @@
 #include <linux/sched.h>
 #include <linux/mm_types.h>
 #include <linux/mm.h>
+#include <linux/page_table_check.h>
 #include <linux/stop_machine.h>
 
 #include <asm/sections.h>
@@ -230,6 +231,9 @@ pmd_t hash__pmdp_collapse_flush(struct v
 
 	pmd = *pmdp;
 	pmd_clear(pmdp);
+
+	page_table_check_pmd_clear(vma->vm_mm, address, pmd);
+
 	/*
 	 * Wait for all pending hash_page to finish. This is needed
 	 * in case of subpage collapse. When we collapse normal pages
--- a/arch/powerpc/mm/book3s64/pgtable.c~powerpc-mm-support-page-table-check
+++ a/arch/powerpc/mm/book3s64/pgtable.c
@@ -10,6 +10,7 @@
 #include <linux/pkeys.h>
 #include <linux/debugfs.h>
 #include <linux/proc_fs.h>
+#include <linux/page_table_check.h>
 
 #include <asm/pgalloc.h>
 #include <asm/tlb.h>
@@ -127,6 +128,7 @@ void set_pmd_at(struct mm_struct *mm, un
 	WARN_ON(!(pmd_leaf(pmd)));
 #endif
 	trace_hugepage_set_pmd(addr, pmd_val(pmd));
+	page_table_check_pmd_set(mm, addr, pmdp, pmd);
 	return set_pte_at_unchecked(mm, addr, pmdp_ptep(pmdp), pmd_pte(pmd));
 }
 
@@ -144,6 +146,7 @@ void set_pud_at(struct mm_struct *mm, un
 	WARN_ON(!(pud_leaf(pud)));
 #endif
 	trace_hugepage_set_pud(addr, pud_val(pud));
+	page_table_check_pud_set(mm, addr, pudp, pud);
 	return set_pte_at_unchecked(mm, addr, pudp_ptep(pudp), pud_pte(pud));
 }
 
@@ -179,23 +182,27 @@ void serialize_against_pte_lookup(struct
 pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 		     pmd_t *pmdp)
 {
-	unsigned long old_pmd;
+	pmd_t old_pmd;
 
 	VM_WARN_ON_ONCE(!pmd_present(*pmdp));
-	old_pmd = pmd_hugepage_update(vma->vm_mm, address, pmdp, _PAGE_PRESENT, _PAGE_INVALID);
+	old_pmd = __pmd(pmd_hugepage_update(vma->vm_mm, address, pmdp, _PAGE_PRESENT, _PAGE_INVALID));
 	flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
-	return __pmd(old_pmd);
+	page_table_check_pmd_clear(vma->vm_mm, address, old_pmd);
+
+	return old_pmd;
 }
 
 pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
 		      pud_t *pudp)
 {
-	unsigned long old_pud;
+	pud_t old_pud;
 
 	VM_WARN_ON_ONCE(!pud_present(*pudp));
-	old_pud = pud_hugepage_update(vma->vm_mm, address, pudp, _PAGE_PRESENT, _PAGE_INVALID);
+	old_pud = __pud(pud_hugepage_update(vma->vm_mm, address, pudp, _PAGE_PRESENT, _PAGE_INVALID));
 	flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
-	return __pud(old_pud);
+	page_table_check_pud_clear(vma->vm_mm, address, old_pud);
+
+	return old_pud;
 }
 
 pmd_t pmdp_huge_get_and_clear_full(struct vm_area_struct *vma,
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c~powerpc-mm-support-page-table-check
+++ a/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -14,6 +14,7 @@
 #include <linux/of.h>
 #include <linux/of_fdt.h>
 #include <linux/mm.h>
+#include <linux/page_table_check.h>
 #include <linux/hugetlb.h>
 #include <linux/string_helpers.h>
 #include <linux/memory.h>
@@ -1474,6 +1475,8 @@ pmd_t radix__pmdp_collapse_flush(struct
 	pmd = *pmdp;
 	pmd_clear(pmdp);
 
+	page_table_check_pmd_clear(vma->vm_mm, address, pmd);
+
 	radix__flush_tlb_collapsed_pmd(vma->vm_mm, address);
 
 	return pmd;
--- a/arch/powerpc/mm/pgtable.c~powerpc-mm-support-page-table-check
+++ a/arch/powerpc/mm/pgtable.c
@@ -22,6 +22,7 @@
 #include <linux/mm.h>
 #include <linux/percpu.h>
 #include <linux/hardirq.h>
+#include <linux/page_table_check.h>
 #include <linux/hugetlb.h>
 #include <asm/tlbflush.h>
 #include <asm/tlb.h>
@@ -206,6 +207,9 @@ void set_ptes(struct mm_struct *mm, unsi
 	 * and not hw_valid ptes. Hence there is no translation cache flush
 	 * involved that need to be batched.
 	 */
+
+	page_table_check_ptes_set(mm, addr, ptep, pte, nr);
+
 	for (;;) {
 
 		/*
_

Patches currently in -mm which might be from rmclure@linux.ibm.com are

mm-page_table_check-reinstate-address-parameter-in-page_table_check_pud_set.patch
mm-page_table_check-reinstate-address-parameter-in-page_table_check_pmd_set.patch
mm-page_table_check-provide-addr-parameter-to-page_table_check_ptes_set.patch
mm-page_table_check-reinstate-address-parameter-in-page_table_check_pud_clear.patch
mm-page_table_check-reinstate-address-parameter-in-page_table_check_pmd_clear.patch
mm-page_table_check-reinstate-address-parameter-in-page_table_check_pte_clear.patch
mm-provide-address-parameter-to-ptemdud_user_accessible_page.patch
powerpc-mm-implement-_user_accessible_page-for-ptes.patch
powerpc-mm-use-set_pte_at_unchecked-for-internal-usages.patch
powerpc-mm-support-page-table-check.patch