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author | Huacai Chen <chenhuacai@loongson.cn> | 2024-08-07 11:37:11 +0200 |
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committer | Huacai Chen <chenhuacai@loongson.cn> | 2024-08-07 11:37:11 +0200 |
commit | 4574815abf43e2bf05643e1b3f7a2e5d6df894f0 (patch) | |
tree | c4f114dabbaa5c9529dd5d0c9a5e97837a564785 /arch/loongarch/include/asm | |
parent | LoongArch: Enable general EFI poweroff method (diff) | |
download | linux-4574815abf43e2bf05643e1b3f7a2e5d6df894f0.tar.xz linux-4574815abf43e2bf05643e1b3f7a2e5d6df894f0.zip |
LoongArch: Use accessors to page table entries instead of direct dereference
As very well explained in commit 20a004e7b017cce282 ("arm64: mm: Use
READ_ONCE/WRITE_ONCE when accessing page tables"), an architecture whose
page table walker can modify the PTE in parallel must use READ_ONCE()/
WRITE_ONCE() macro to avoid any compiler transformation.
So apply that to LoongArch which is such an architecture, in order to
avoid potential problems.
Similar to commit edf955647269422e ("riscv: Use accessors to page table
entries instead of direct dereference").
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Diffstat (limited to 'arch/loongarch/include/asm')
-rw-r--r-- | arch/loongarch/include/asm/hugetlb.h | 4 | ||||
-rw-r--r-- | arch/loongarch/include/asm/kfence.h | 6 | ||||
-rw-r--r-- | arch/loongarch/include/asm/pgtable.h | 48 |
3 files changed, 34 insertions, 24 deletions
diff --git a/arch/loongarch/include/asm/hugetlb.h b/arch/loongarch/include/asm/hugetlb.h index aa44b3fe43dd..5da32c00d483 100644 --- a/arch/loongarch/include/asm/hugetlb.h +++ b/arch/loongarch/include/asm/hugetlb.h @@ -34,7 +34,7 @@ static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { pte_t clear; - pte_t pte = *ptep; + pte_t pte = ptep_get(ptep); pte_val(clear) = (unsigned long)invalid_pte_table; set_pte_at(mm, addr, ptep, clear); @@ -65,7 +65,7 @@ static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma, pte_t *ptep, pte_t pte, int dirty) { - int changed = !pte_same(*ptep, pte); + int changed = !pte_same(ptep_get(ptep), pte); if (changed) { set_pte_at(vma->vm_mm, addr, ptep, pte); diff --git a/arch/loongarch/include/asm/kfence.h b/arch/loongarch/include/asm/kfence.h index 92636e82957c..da9e93024626 100644 --- a/arch/loongarch/include/asm/kfence.h +++ b/arch/loongarch/include/asm/kfence.h @@ -53,13 +53,13 @@ static inline bool kfence_protect_page(unsigned long addr, bool protect) { pte_t *pte = virt_to_kpte(addr); - if (WARN_ON(!pte) || pte_none(*pte)) + if (WARN_ON(!pte) || pte_none(ptep_get(pte))) return false; if (protect) - set_pte(pte, __pte(pte_val(*pte) & ~(_PAGE_VALID | _PAGE_PRESENT))); + set_pte(pte, __pte(pte_val(ptep_get(pte)) & ~(_PAGE_VALID | _PAGE_PRESENT))); else - set_pte(pte, __pte(pte_val(*pte) | (_PAGE_VALID | _PAGE_PRESENT))); + set_pte(pte, __pte(pte_val(ptep_get(pte)) | (_PAGE_VALID | _PAGE_PRESENT))); preempt_disable(); local_flush_tlb_one(addr); diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h index 3fbf1f37c58e..85431f20a14d 100644 --- a/arch/loongarch/include/asm/pgtable.h +++ b/arch/loongarch/include/asm/pgtable.h @@ -106,6 +106,9 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]; #define KFENCE_AREA_START (VMEMMAP_END + 1) #define KFENCE_AREA_END (KFENCE_AREA_START + KFENCE_AREA_SIZE - 1) +#define ptep_get(ptep) READ_ONCE(*(ptep)) +#define pmdp_get(pmdp) READ_ONCE(*(pmdp)) + #define pte_ERROR(e) \ pr_err("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e)) #ifndef __PAGETABLE_PMD_FOLDED @@ -147,11 +150,6 @@ static inline int p4d_present(p4d_t p4d) return p4d_val(p4d) != (unsigned long)invalid_pud_table; } -static inline void p4d_clear(p4d_t *p4dp) -{ - p4d_val(*p4dp) = (unsigned long)invalid_pud_table; -} - static inline pud_t *p4d_pgtable(p4d_t p4d) { return (pud_t *)p4d_val(p4d); @@ -159,7 +157,12 @@ static inline pud_t *p4d_pgtable(p4d_t p4d) static inline void set_p4d(p4d_t *p4d, p4d_t p4dval) { - *p4d = p4dval; + WRITE_ONCE(*p4d, p4dval); +} + +static inline void p4d_clear(p4d_t *p4dp) +{ + set_p4d(p4dp, __p4d((unsigned long)invalid_pud_table)); } #define p4d_phys(p4d) PHYSADDR(p4d_val(p4d)) @@ -193,17 +196,20 @@ static inline int pud_present(pud_t pud) return pud_val(pud) != (unsigned long)invalid_pmd_table; } -static inline void pud_clear(pud_t *pudp) +static inline pmd_t *pud_pgtable(pud_t pud) { - pud_val(*pudp) = ((unsigned long)invalid_pmd_table); + return (pmd_t *)pud_val(pud); } -static inline pmd_t *pud_pgtable(pud_t pud) +static inline void set_pud(pud_t *pud, pud_t pudval) { - return (pmd_t *)pud_val(pud); + WRITE_ONCE(*pud, pudval); } -#define set_pud(pudptr, pudval) do { *(pudptr) = (pudval); } while (0) +static inline void pud_clear(pud_t *pudp) +{ + set_pud(pudp, __pud((unsigned long)invalid_pmd_table)); +} #define pud_phys(pud) PHYSADDR(pud_val(pud)) #define pud_page(pud) (pfn_to_page(pud_phys(pud) >> PAGE_SHIFT)) @@ -231,12 +237,15 @@ static inline int pmd_present(pmd_t pmd) return pmd_val(pmd) != (unsigned long)invalid_pte_table; } -static inline void pmd_clear(pmd_t *pmdp) +static inline void set_pmd(pmd_t *pmd, pmd_t pmdval) { - pmd_val(*pmdp) = ((unsigned long)invalid_pte_table); + WRITE_ONCE(*pmd, pmdval); } -#define set_pmd(pmdptr, pmdval) do { *(pmdptr) = (pmdval); } while (0) +static inline void pmd_clear(pmd_t *pmdp) +{ + set_pmd(pmdp, __pmd((unsigned long)invalid_pte_table)); +} #define pmd_phys(pmd) PHYSADDR(pmd_val(pmd)) @@ -314,7 +323,8 @@ extern void paging_init(void); static inline void set_pte(pte_t *ptep, pte_t pteval) { - *ptep = pteval; + WRITE_ONCE(*ptep, pteval); + if (pte_val(pteval) & _PAGE_GLOBAL) { pte_t *buddy = ptep_buddy(ptep); /* @@ -341,8 +351,8 @@ static inline void set_pte(pte_t *ptep, pte_t pteval) : [buddy] "+m" (buddy->pte), [tmp] "=&r" (tmp) : [global] "r" (page_global)); #else /* !CONFIG_SMP */ - if (pte_none(*buddy)) - pte_val(*buddy) = pte_val(*buddy) | _PAGE_GLOBAL; + if (pte_none(ptep_get(buddy))) + WRITE_ONCE(*buddy, __pte(pte_val(ptep_get(buddy)) | _PAGE_GLOBAL)); #endif /* CONFIG_SMP */ } } @@ -350,7 +360,7 @@ static inline void set_pte(pte_t *ptep, pte_t pteval) static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { /* Preserve global status for the pair */ - if (pte_val(*ptep_buddy(ptep)) & _PAGE_GLOBAL) + if (pte_val(ptep_get(ptep_buddy(ptep))) & _PAGE_GLOBAL) set_pte(ptep, __pte(_PAGE_GLOBAL)); else set_pte(ptep, __pte(0)); @@ -603,7 +613,7 @@ static inline pmd_t pmd_mkinvalid(pmd_t pmd) static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, unsigned long address, pmd_t *pmdp) { - pmd_t old = *pmdp; + pmd_t old = pmdp_get(pmdp); pmd_clear(pmdp); |