These new helpers will be needed for pud entry updates soon. Introduce these helpers by referencing the pmd ones. Namely:
- pudp_invalidate() - pud_modify() Cc: Thomas Gleixner <t...@linutronix.de> Cc: Ingo Molnar <mi...@redhat.com> Cc: Borislav Petkov <b...@alien8.de> Cc: Dave Hansen <dave.han...@linux.intel.com> Cc: x...@kernel.org Signed-off-by: Peter Xu <pet...@redhat.com> --- arch/x86/include/asm/pgtable.h | 55 +++++++++++++++++++++++++++++----- arch/x86/mm/pgtable.c | 11 +++++++ 2 files changed, 58 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index cdf044c2ad6e..701593c53f3b 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -782,6 +782,12 @@ static inline pmd_t pmd_mkinvalid(pmd_t pmd) __pgprot(pmd_flags(pmd) & ~(_PAGE_PRESENT|_PAGE_PROTNONE))); } +static inline pud_t pud_mkinvalid(pud_t pud) +{ + return pfn_pud(pud_pfn(pud), + __pgprot(pud_flags(pud) & ~(_PAGE_PRESENT|_PAGE_PROTNONE))); +} + static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask); static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) @@ -829,14 +835,8 @@ static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) pmd_result = __pmd(val); /* - * To avoid creating Write=0,Dirty=1 PMDs, pte_modify() needs to avoid: - * 1. Marking Write=0 PMDs Dirty=1 - * 2. Marking Dirty=1 PMDs Write=0 - * - * The first case cannot happen because the _PAGE_CHG_MASK will filter - * out any Dirty bit passed in newprot. Handle the second case by - * going through the mksaveddirty exercise. Only do this if the old - * value was Write=1 to avoid doing this on Shadow Stack PTEs. + * Avoid creating shadow stack PMD by accident. See comment in + * pte_modify(). */ if (oldval & _PAGE_RW) pmd_result = pmd_mksaveddirty(pmd_result); @@ -846,6 +846,29 @@ static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) return pmd_result; } +static inline pud_t pud_modify(pud_t pud, pgprot_t newprot) +{ + pudval_t val = pud_val(pud), oldval = val; + pud_t pud_result; + + val &= _HPAGE_CHG_MASK; + val |= check_pgprot(newprot) & ~_HPAGE_CHG_MASK; + val = flip_protnone_guard(oldval, val, PHYSICAL_PUD_PAGE_MASK); + + pud_result = __pud(val); + + /* + * Avoid creating shadow stack PUD by accident. See comment in + * pte_modify(). + */ + if (oldval & _PAGE_RW) + pud_result = pud_mksaveddirty(pud_result); + else + pud_result = pud_clear_saveddirty(pud_result); + + return pud_result; +} + /* * mprotect needs to preserve PAT and encryption bits when updating * vm_page_prot @@ -1384,10 +1407,26 @@ static inline pmd_t pmdp_establish(struct vm_area_struct *vma, } #endif +static inline pud_t pudp_establish(struct vm_area_struct *vma, + unsigned long address, pud_t *pudp, pud_t pud) +{ + page_table_check_pud_set(vma->vm_mm, pudp, pud); + if (IS_ENABLED(CONFIG_SMP)) { + return xchg(pudp, pud); + } else { + pud_t old = *pudp; + WRITE_ONCE(*pudp, pud); + return old; + } +} + #define __HAVE_ARCH_PMDP_INVALIDATE_AD extern pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp); +pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address, + pud_t *pudp); + /* * Page table pages are page-aligned. The lower half of the top * level is used for userspace and the top half for the kernel. diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index 564b8945951e..9d97a1b99160 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -641,6 +641,17 @@ pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma, unsigned long address, } #endif +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address, + pud_t *pudp) +{ + VM_WARN_ON_ONCE(!pud_present(*pudp)); + pud_t old = pudp_establish(vma, address, pudp, pud_mkinvalid(*pudp)); + flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE); + return old; +} +#endif + /** * reserve_top_address - reserves a hole in the top of kernel address space * @reserve - size of hole to reserve -- 2.45.0