Le 30/11/2023 à 03:53, Rohan McLure a écrit :
> 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().
>
> Cause API-facing routines that call set_pte_at() to instead call
> __set_pte_at(), which will remain uninstrumented by page table check.
> set_ptes() is itself implemented by calls to __set_pte_at(), so this
> eliminates redundant code.
>
> Also prefer __set_pte_at() in early-boot usages which should not be
> instrumented.
__set_pte_at() lacks the call to set_pte_filter() and is only intended
to be called directly in very specific situations like early KASAN where
set_pte_filter() cannot be called but where we absolutely know that
set_pte_filter() is not needed.
Are you really sure that all places you change are safe and do not
require a call to set_pte_filter() ?
>
> Signed-off-by: Rohan McLure <rmcl...@linux.ibm.com>
> ---
> v9: New patch
> ---
> arch/powerpc/mm/book3s64/hash_pgtable.c | 2 +-
> arch/powerpc/mm/book3s64/pgtable.c | 4 ++--
> arch/powerpc/mm/book3s64/radix_pgtable.c | 10 +++++-----
> arch/powerpc/mm/nohash/book3e_pgtable.c | 2 +-
> arch/powerpc/mm/pgtable_32.c | 2 +-
> 5 files changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/arch/powerpc/mm/book3s64/hash_pgtable.c
> b/arch/powerpc/mm/book3s64/hash_pgtable.c
> index 988948d69bc1..ae52c8db45b7 100644
> --- a/arch/powerpc/mm/book3s64/hash_pgtable.c
> +++ b/arch/powerpc/mm/book3s64/hash_pgtable.c
> @@ -165,7 +165,7 @@ int hash__map_kernel_page(unsigned long ea, unsigned long
> pa, pgprot_t prot)
> ptep = pte_alloc_kernel(pmdp, ea);
> if (!ptep)
> return -ENOMEM;
> - set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, prot));
> + __set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
> prot), 0);
> } else {
> /*
> * If the mm subsystem is not fully up, we cannot create a
> diff --git a/arch/powerpc/mm/book3s64/pgtable.c
> b/arch/powerpc/mm/book3s64/pgtable.c
> index be229290a6a7..9a0a2accb261 100644
> --- a/arch/powerpc/mm/book3s64/pgtable.c
> +++ b/arch/powerpc/mm/book3s64/pgtable.c
> @@ -116,7 +116,7 @@ void set_pmd_at(struct mm_struct *mm, unsigned long addr,
> WARN_ON(!(pmd_large(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(mm, addr, pmdp_ptep(pmdp), pmd_pte(pmd), 0);
> }
>
> void set_pud_at(struct mm_struct *mm, unsigned long addr,
> @@ -539,7 +539,7 @@ 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(vma->vm_mm, addr, ptep, pte, 0);
> }
>
> /*
> diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c
> b/arch/powerpc/mm/book3s64/radix_pgtable.c
> index 1f8db10693e3..ae4a5f66ccd2 100644
> --- a/arch/powerpc/mm/book3s64/radix_pgtable.c
> +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
> @@ -109,7 +109,7 @@ static int early_map_kernel_page(unsigned long ea,
> unsigned long pa,
> ptep = pte_offset_kernel(pmdp, ea);
>
> set_the_pte:
> - set_pte_at(&init_mm, ea, ptep, pfn_pte(pfn, flags));
> + __set_pte_at(&init_mm, ea, ptep, pfn_pte(pfn, flags), 0);
> asm volatile("ptesync": : :"memory");
> return 0;
> }
> @@ -169,7 +169,7 @@ static int __map_kernel_page(unsigned long ea, unsigned
> long pa,
> return -ENOMEM;
>
> set_the_pte:
> - set_pte_at(&init_mm, ea, ptep, pfn_pte(pfn, flags));
> + __set_pte_at(&init_mm, ea, ptep, pfn_pte(pfn, flags), 0);
> asm volatile("ptesync": : :"memory");
> return 0;
> }
> @@ -1536,7 +1536,7 @@ 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(mm, addr, ptep, pte, 0);
> }
>
> int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
> @@ -1547,7 +1547,7 @@ 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(&init_mm, 0 /* radix unused */, ptep, new_pud, 0);
>
> return 1;
> }
> @@ -1594,7 +1594,7 @@ 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(&init_mm, 0 /* radix unused */, ptep, new_pmd, 0);
>
> return 1;
> }
> diff --git a/arch/powerpc/mm/nohash/book3e_pgtable.c
> b/arch/powerpc/mm/nohash/book3e_pgtable.c
> index 1c5e4ecbebeb..4de91b54fd89 100644
> --- a/arch/powerpc/mm/nohash/book3e_pgtable.c
> +++ b/arch/powerpc/mm/nohash/book3e_pgtable.c
> @@ -111,7 +111,7 @@ int __ref map_kernel_page(unsigned long ea, phys_addr_t
> pa, pgprot_t prot)
> }
> ptep = pte_offset_kernel(pmdp, ea);
> }
> - set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, prot));
> + __set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, prot), 0);
>
> smp_wmb();
> return 0;
> diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
> index 5c02fd08d61e..4bf3ca6af7cd 100644
> --- a/arch/powerpc/mm/pgtable_32.c
> +++ b/arch/powerpc/mm/pgtable_32.c
> @@ -89,7 +89,7 @@ int __ref map_kernel_page(unsigned long va, phys_addr_t pa,
> pgprot_t prot)
> * hash table
> */
> BUG_ON((pte_present(*pg) | pte_hashpte(*pg)) &&
> pgprot_val(prot));
> - set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, prot));
> + __set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, prot),
> 0);
> }
> smp_wmb();
> return err;
