The patch titled
Subject: powerpc: mm: use set_pte_at_unchecked() for internal usages
has been added to the -mm mm-unstable branch. Its filename is
powerpc-mm-use-set_pte_at_unchecked-for-internal-usages.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/powerpc-mm-use-set_pte_at_unchecked-for-internal-usages.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Rohan McLure <rmclure@xxxxxxxxxxxxx>
Subject: powerpc: mm: use set_pte_at_unchecked() for internal usages
Date: Wed, 12 Feb 2025 03:14:03 +1100
In the new set_ptes() API, set_pte_at() (a special case of set_ptes()) is
intended to be instrumented by the page table check facility. There are
however several other routines that constitute the API for setting page
table entries, including set_pmd_at() among others. Such routines are
themselves implemented in terms of set_ptes_at().
A future patch providing support for page table checking on powerpc must
take care to avoid duplicate calls to page_table_check_p{te,md,ud}_set().
Allow for assignment of pte entries without instrumentation through the
set_pte_at_unchecked() routine introduced in this patch.
Cause API-facing routines that call set_pte_at() to instead call
set_pte_at_unchecked(), which will remain uninstrumented by page table
check. set_ptes() is itself implemented by calls to __set_pte_at(), so
this eliminates redundant code.
[ajd@xxxxxxxxxxxxx: don't change to unchecked for early boot/kernel mappings]
Link: https://lkml.kernel.org/r/20250211161404.850215-11-ajd@xxxxxxxxxxxxx
Signed-off-by: Rohan McLure <rmclure@xxxxxxxxxxxxx>
Signed-off-by: Andrew Donnellan <ajd@xxxxxxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Sweet Tea Dorminy <sweettea-kernel@xxxxxxxxxx>
Cc: <x86@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/include/asm/pgtable.h | 2 ++
arch/powerpc/mm/book3s64/pgtable.c | 6 +++---
arch/powerpc/mm/book3s64/radix_pgtable.c | 6 +++---
arch/powerpc/mm/pgtable.c | 8 ++++++++
4 files changed, 16 insertions(+), 6 deletions(-)
--- a/arch/powerpc/include/asm/pgtable.h~powerpc-mm-use-set_pte_at_unchecked-for-internal-usages
+++ a/arch/powerpc/include/asm/pgtable.h
@@ -46,6 +46,8 @@ struct mm_struct;
void set_ptes(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
pte_t pte, unsigned int nr);
#define set_ptes set_ptes
+void set_pte_at_unchecked(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pte);
#define update_mmu_cache(vma, addr, ptep) \
update_mmu_cache_range(NULL, vma, addr, ptep, 1)
--- a/arch/powerpc/mm/book3s64/pgtable.c~powerpc-mm-use-set_pte_at_unchecked-for-internal-usages
+++ a/arch/powerpc/mm/book3s64/pgtable.c
@@ -129,7 +129,7 @@ void set_pmd_at(struct mm_struct *mm, un
WARN_ON(!(pmd_leaf(pmd)));
#endif
trace_hugepage_set_pmd(addr, pmd_val(pmd));
- return set_pte_at(mm, addr, pmdp_ptep(pmdp), pmd_pte(pmd));
+ return set_pte_at_unchecked(mm, addr, pmdp_ptep(pmdp), pmd_pte(pmd));
}
void set_pud_at(struct mm_struct *mm, unsigned long addr,
@@ -146,7 +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));
- return set_pte_at(mm, addr, pudp_ptep(pudp), pud_pte(pud));
+ return set_pte_at_unchecked(mm, addr, pudp_ptep(pudp), pud_pte(pud));
}
static void do_serialize(void *arg)
@@ -557,7 +557,7 @@ void ptep_modify_prot_commit(struct vm_a
if (radix_enabled())
return radix__ptep_modify_prot_commit(vma, addr,
ptep, old_pte, pte);
- set_pte_at(vma->vm_mm, addr, ptep, pte);
+ set_pte_at_unchecked(vma->vm_mm, addr, ptep, pte);
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c~powerpc-mm-use-set_pte_at_unchecked-for-internal-usages
+++ a/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -1586,7 +1586,7 @@ void radix__ptep_modify_prot_commit(stru
(atomic_read(&mm->context.copros) > 0))
radix__flush_tlb_page(vma, addr);
- set_pte_at(mm, addr, ptep, pte);
+ set_pte_at_unchecked(mm, addr, ptep, pte);
}
int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
@@ -1597,7 +1597,7 @@ int pud_set_huge(pud_t *pud, phys_addr_t
if (!radix_enabled())
return 0;
- set_pte_at(&init_mm, 0 /* radix unused */, ptep, new_pud);
+ set_pte_at_unchecked(&init_mm, 0 /* radix unused */, ptep, new_pud);
return 1;
}
@@ -1644,7 +1644,7 @@ int pmd_set_huge(pmd_t *pmd, phys_addr_t
if (!radix_enabled())
return 0;
- set_pte_at(&init_mm, 0 /* radix unused */, ptep, new_pmd);
+ set_pte_at_unchecked(&init_mm, 0 /* radix unused */, ptep, new_pmd);
return 1;
}
--- a/arch/powerpc/mm/pgtable.c~powerpc-mm-use-set_pte_at_unchecked-for-internal-usages
+++ a/arch/powerpc/mm/pgtable.c
@@ -224,6 +224,14 @@ void set_ptes(struct mm_struct *mm, unsi
}
}
+void set_pte_at_unchecked(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pte)
+{
+ VM_WARN_ON(pte_hw_valid(*ptep) && !pte_protnone(*ptep));
+ pte = set_pte_filter(pte, addr);
+ __set_pte_at(mm, addr, ptep, pte, 0);
+}
+
void unmap_kernel_page(unsigned long va)
{
pmd_t *pmdp = pmd_off_k(va);
_
Patches currently in -mm which might be from rmclure@xxxxxxxxxxxxx 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_pte_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-add-pud_pfn-stub.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
