powerpc: mm: use set_pte_at_unchecked() for internal usages

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@linux.ibm.com: don't change to unchecked for early boot/kernel mappings]
Link: https://lkml.kernel.org/r/20250813062614.51759-13-ajd@linux.ibm.com
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Acked-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index d0938e9c33fb4d97f0908840f11d7421c84b9739..4fe9709921471f900b5fe4964772da8676b740f8 100644 (file)
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/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)
 

diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c
index c9431ae7f78a0e0b19e3244024454047a1815c2e..ff0c5a1988f81a9748c58722e16e6758befca94e 100644 (file)
--- a/arch/powerpc/mm/book3s64/pgtable.c
+++ b/arch/powerpc/mm/book3s64/pgtable.c
@@ -127,7 +127,7 @@ void set_pmd_at(struct mm_struct *mm, unsigned long addr,
        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,
@@ -144,7 +144,7 @@ void set_pud_at(struct mm_struct *mm, unsigned long addr,
        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)
@@ -549,7 +549,7 @@ void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr,
        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

diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index be523e5fe9c51238d8a594bc9ca0b0938b29f9de..8c3b0f1750e48101383f929c55f26b7d1c4f3849 100644 (file)
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -1606,7 +1606,7 @@ void radix__ptep_modify_prot_commit(struct vm_area_struct *vma,
            (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)
@@ -1617,7 +1617,7 @@ int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
        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;
 }
@@ -1664,7 +1664,7 @@ int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
        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;
 }

diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
index dfaa9fd86f7eaac9562607e5f33010eac785d00e..bf90becb6cd6c3b2fa68816db872512bb7c4537c 100644 (file)
--- a/arch/powerpc/mm/pgtable.c
+++ b/arch/powerpc/mm/pgtable.c
@@ -224,6 +224,14 @@ void set_ptes(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
        }
 }
 
+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);