Re: [PATCH v10 11/12] powerpc: mm: Use set_pte_at_unchecked() for early-boot / internal usages
From: Christophe Leroy <hidden>
Date: 2024-03-13 11:30:15
Also in:
linux-arm-kernel, linux-mm, linux-riscv
Le 13/03/2024 à 05:21, 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(). 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.
Also prefer set_pte_at_unchecked() in early-boot usages which should not be
instrumented.
Signed-off-by: Rohan McLure <redacted>
---
v9: New patch
v10: don't reuse __set_pte_at(), as that will not apply filters. Instead
use new set_pte_at_unchecked().Are filters needed at all in those usecases ?
quoted hunk ↗ jump to hunk
--- arch/powerpc/include/asm/pgtable.h | 2 ++ arch/powerpc/mm/book3s64/hash_pgtable.c | 2 +- arch/powerpc/mm/book3s64/pgtable.c | 6 +++--- arch/powerpc/mm/book3s64/radix_pgtable.c | 8 ++++---- arch/powerpc/mm/nohash/book3e_pgtable.c | 2 +- arch/powerpc/mm/pgtable.c | 7 +++++++ arch/powerpc/mm/pgtable_32.c | 2 +- 7 files changed, 19 insertions(+), 10 deletions(-)diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h index 3741a63fb82e..6ff1d8cfa216 100644 --- a/arch/powerpc/include/asm/pgtable.h +++ b/arch/powerpc/include/asm/pgtable.h@@ -44,6 +44,8 @@ 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/hash_pgtable.c b/arch/powerpc/mm/book3s64/hash_pgtable.c index 988948d69bc1..871472f99a01 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_unchecked(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, prot)); } else { /* * If the mm subsystem is not fully up, we cannot create adiff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c index 3438ab72c346..25082ab6018b 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_unchecked(mm, addr, pmdp_ptep(pmdp), pmd_pte(pmd)); } void set_pud_at(struct mm_struct *mm, unsigned long addr,@@ -133,7 +133,7 @@ void set_pud_at(struct mm_struct *mm, unsigned long addr, WARN_ON(!(pud_large(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)@@ -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_unchecked(vma->vm_mm, addr, ptep, pte); } #ifdef CONFIG_TRANSPARENT_HUGEPAGEdiff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c index 46fa46ce6526..c661e42bb2f1 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_unchecked(&init_mm, ea, ptep, pfn_pte(pfn, flags)); asm volatile("ptesync": : :"memory"); return 0; }@@ -1522,7 +1522,7 @@ 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)@@ -1533,7 +1533,7 @@ 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; }@@ -1580,7 +1580,7 @@ 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/nohash/book3e_pgtable.c b/arch/powerpc/mm/nohash/book3e_pgtable.c index 1c5e4ecbebeb..10d487b2b991 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_unchecked(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, prot)); smp_wmb(); return 0;diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c index e8e0289d7ab0..352679cf2684 100644 --- a/arch/powerpc/mm/pgtable.c +++ b/arch/powerpc/mm/pgtable.c@@ -227,6 +227,13 @@ 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) +{
No need of the VM_WARN_ON(pte_hw_valid(*ptep) && !pte_protnone(*ptep)); which is in set_ptes() ?
quoted hunk ↗ jump to hunk
+ 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);diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c index 4be97b4a44f9..a5a26faf91ec 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_unchecked(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, prot)); } smp_wmb(); return err;