From 0a9fe8ca844d43f3f547f0e166122b6048121c8f Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Tue, 4 Dec 2018 13:37:21 -0800 Subject: [PATCH] x86/mm: Validate kernel_physical_mapping_init() PTE population The usage of __flush_tlb_all() in the kernel_physical_mapping_init() path is not necessary. In general flushing the TLB is not required when updating an entry from the !present state. However, to give confidence in the future removal of TLB flushing in this path, use the new set_pte_safe() family of helpers to assert that the !present assumption is true in this path. [ mingo: Minor readability edits. ] Suggested-by: Peter Zijlstra Suggested-by: Dave Hansen Signed-off-by: Dan Williams Acked-by: Kirill A. Shutemov Acked-by: Peter Zijlstra (Intel) Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Rik van Riel Cc: Sebastian Andrzej Siewior Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/154395944177.32119.8524957429632012270.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/pgalloc.h | 27 ++++++++++++++++++++++++ arch/x86/mm/init_64.c | 24 ++++++++++----------- include/asm-generic/5level-fixup.h | 1 + include/asm-generic/pgtable-nop4d-hack.h | 1 + include/asm-generic/pgtable-nop4d.h | 1 + include/asm-generic/pgtable-nopud.h | 1 + 6 files changed, 43 insertions(+), 12 deletions(-) diff --git a/arch/x86/include/asm/pgalloc.h b/arch/x86/include/asm/pgalloc.h index ec7f43327033..1ea41aaef68b 100644 --- a/arch/x86/include/asm/pgalloc.h +++ b/arch/x86/include/asm/pgalloc.h @@ -80,6 +80,13 @@ static inline void pmd_populate_kernel(struct mm_struct *mm, set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE)); } +static inline void pmd_populate_kernel_safe(struct mm_struct *mm, + pmd_t *pmd, pte_t *pte) +{ + paravirt_alloc_pte(mm, __pa(pte) >> PAGE_SHIFT); + set_pmd_safe(pmd, __pmd(__pa(pte) | _PAGE_TABLE)); +} + static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd, struct page *pte) { @@ -132,6 +139,12 @@ static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd) paravirt_alloc_pmd(mm, __pa(pmd) >> PAGE_SHIFT); set_pud(pud, __pud(_PAGE_TABLE | __pa(pmd))); } + +static inline void pud_populate_safe(struct mm_struct *mm, pud_t *pud, pmd_t *pmd) +{ + paravirt_alloc_pmd(mm, __pa(pmd) >> PAGE_SHIFT); + set_pud_safe(pud, __pud(_PAGE_TABLE | __pa(pmd))); +} #endif /* CONFIG_X86_PAE */ #if CONFIG_PGTABLE_LEVELS > 3 @@ -141,6 +154,12 @@ static inline void p4d_populate(struct mm_struct *mm, p4d_t *p4d, pud_t *pud) set_p4d(p4d, __p4d(_PAGE_TABLE | __pa(pud))); } +static inline void p4d_populate_safe(struct mm_struct *mm, p4d_t *p4d, pud_t *pud) +{ + paravirt_alloc_pud(mm, __pa(pud) >> PAGE_SHIFT); + set_p4d_safe(p4d, __p4d(_PAGE_TABLE | __pa(pud))); +} + static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr) { gfp_t gfp = GFP_KERNEL_ACCOUNT; @@ -173,6 +192,14 @@ static inline void pgd_populate(struct mm_struct *mm, pgd_t *pgd, p4d_t *p4d) set_pgd(pgd, __pgd(_PAGE_TABLE | __pa(p4d))); } +static inline void pgd_populate_safe(struct mm_struct *mm, pgd_t *pgd, p4d_t *p4d) +{ + if (!pgtable_l5_enabled()) + return; + paravirt_alloc_p4d(mm, __pa(p4d) >> PAGE_SHIFT); + set_pgd_safe(pgd, __pgd(_PAGE_TABLE | __pa(p4d))); +} + static inline p4d_t *p4d_alloc_one(struct mm_struct *mm, unsigned long addr) { gfp_t gfp = GFP_KERNEL_ACCOUNT; diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 5fab264948c2..3e25ac2793ef 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -432,7 +432,7 @@ phys_pte_init(pte_t *pte_page, unsigned long paddr, unsigned long paddr_end, E820_TYPE_RAM) && !e820__mapped_any(paddr & PAGE_MASK, paddr_next, E820_TYPE_RESERVED_KERN)) - set_pte(pte, __pte(0)); + set_pte_safe(pte, __pte(0)); continue; } @@ -452,7 +452,7 @@ phys_pte_init(pte_t *pte_page, unsigned long paddr, unsigned long paddr_end, pr_info(" pte=%p addr=%lx pte=%016lx\n", pte, paddr, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL).pte); pages++; - set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, prot)); + set_pte_safe(pte, pfn_pte(paddr >> PAGE_SHIFT, prot)); paddr_last = (paddr & PAGE_MASK) + PAGE_SIZE; } @@ -487,7 +487,7 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long paddr, unsigned long paddr_end, E820_TYPE_RAM) && !e820__mapped_any(paddr & PMD_MASK, paddr_next, E820_TYPE_RESERVED_KERN)) - set_pmd(pmd, __pmd(0)); + set_pmd_safe(pmd, __pmd(0)); continue; } @@ -524,7 +524,7 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long paddr, unsigned long paddr_end, if (page_size_mask & (1<> PAGE_SHIFT, __pgprot(pgprot_val(prot) | _PAGE_PSE))); spin_unlock(&init_mm.page_table_lock); @@ -536,7 +536,7 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long paddr, unsigned long paddr_end, paddr_last = phys_pte_init(pte, paddr, paddr_end, new_prot); spin_lock(&init_mm.page_table_lock); - pmd_populate_kernel(&init_mm, pmd, pte); + pmd_populate_kernel_safe(&init_mm, pmd, pte); spin_unlock(&init_mm.page_table_lock); } update_page_count(PG_LEVEL_2M, pages); @@ -573,7 +573,7 @@ phys_pud_init(pud_t *pud_page, unsigned long paddr, unsigned long paddr_end, E820_TYPE_RAM) && !e820__mapped_any(paddr & PUD_MASK, paddr_next, E820_TYPE_RESERVED_KERN)) - set_pud(pud, __pud(0)); + set_pud_safe(pud, __pud(0)); continue; } @@ -611,7 +611,7 @@ phys_pud_init(pud_t *pud_page, unsigned long paddr, unsigned long paddr_end, if (page_size_mask & (1<> PAGE_SHIFT, PAGE_KERNEL_LARGE)); spin_unlock(&init_mm.page_table_lock); @@ -624,7 +624,7 @@ phys_pud_init(pud_t *pud_page, unsigned long paddr, unsigned long paddr_end, page_size_mask, prot); spin_lock(&init_mm.page_table_lock); - pud_populate(&init_mm, pud, pmd); + pud_populate_safe(&init_mm, pud, pmd); spin_unlock(&init_mm.page_table_lock); } __flush_tlb_all(); @@ -659,7 +659,7 @@ phys_p4d_init(p4d_t *p4d_page, unsigned long paddr, unsigned long paddr_end, E820_TYPE_RAM) && !e820__mapped_any(paddr & P4D_MASK, paddr_next, E820_TYPE_RESERVED_KERN)) - set_p4d(p4d, __p4d(0)); + set_p4d_safe(p4d, __p4d(0)); continue; } @@ -677,7 +677,7 @@ phys_p4d_init(p4d_t *p4d_page, unsigned long paddr, unsigned long paddr_end, page_size_mask); spin_lock(&init_mm.page_table_lock); - p4d_populate(&init_mm, p4d, pud); + p4d_populate_safe(&init_mm, p4d, pud); spin_unlock(&init_mm.page_table_lock); } __flush_tlb_all(); @@ -723,9 +723,9 @@ kernel_physical_mapping_init(unsigned long paddr_start, spin_lock(&init_mm.page_table_lock); if (pgtable_l5_enabled()) - pgd_populate(&init_mm, pgd, p4d); + pgd_populate_safe(&init_mm, pgd, p4d); else - p4d_populate(&init_mm, p4d_offset(pgd, vaddr), (pud_t *) p4d); + p4d_populate_safe(&init_mm, p4d_offset(pgd, vaddr), (pud_t *) p4d); spin_unlock(&init_mm.page_table_lock); pgd_changed = true; } diff --git a/include/asm-generic/5level-fixup.h b/include/asm-generic/5level-fixup.h index 73474bb52344..bb6cb347018c 100644 --- a/include/asm-generic/5level-fixup.h +++ b/include/asm-generic/5level-fixup.h @@ -26,6 +26,7 @@ #define p4d_clear(p4d) pgd_clear(p4d) #define p4d_val(p4d) pgd_val(p4d) #define p4d_populate(mm, p4d, pud) pgd_populate(mm, p4d, pud) +#define p4d_populate_safe(mm, p4d, pud) pgd_populate(mm, p4d, pud) #define p4d_page(p4d) pgd_page(p4d) #define p4d_page_vaddr(p4d) pgd_page_vaddr(p4d) diff --git a/include/asm-generic/pgtable-nop4d-hack.h b/include/asm-generic/pgtable-nop4d-hack.h index 1d6dd38c0e5e..829bdb0d6327 100644 --- a/include/asm-generic/pgtable-nop4d-hack.h +++ b/include/asm-generic/pgtable-nop4d-hack.h @@ -31,6 +31,7 @@ static inline void pgd_clear(pgd_t *pgd) { } #define pud_ERROR(pud) (pgd_ERROR((pud).pgd)) #define pgd_populate(mm, pgd, pud) do { } while (0) +#define pgd_populate_safe(mm, pgd, pud) do { } while (0) /* * (puds are folded into pgds so this doesn't get actually called, * but the define is needed for a generic inline function.) diff --git a/include/asm-generic/pgtable-nop4d.h b/include/asm-generic/pgtable-nop4d.h index 04cb913797bc..aebab905e6cd 100644 --- a/include/asm-generic/pgtable-nop4d.h +++ b/include/asm-generic/pgtable-nop4d.h @@ -26,6 +26,7 @@ static inline void pgd_clear(pgd_t *pgd) { } #define p4d_ERROR(p4d) (pgd_ERROR((p4d).pgd)) #define pgd_populate(mm, pgd, p4d) do { } while (0) +#define pgd_populate_safe(mm, pgd, p4d) do { } while (0) /* * (p4ds are folded into pgds so this doesn't get actually called, * but the define is needed for a generic inline function.) diff --git a/include/asm-generic/pgtable-nopud.h b/include/asm-generic/pgtable-nopud.h index 9bef475db6fe..c77a1d301155 100644 --- a/include/asm-generic/pgtable-nopud.h +++ b/include/asm-generic/pgtable-nopud.h @@ -35,6 +35,7 @@ static inline void p4d_clear(p4d_t *p4d) { } #define pud_ERROR(pud) (p4d_ERROR((pud).p4d)) #define p4d_populate(mm, p4d, pud) do { } while (0) +#define p4d_populate_safe(mm, p4d, pud) do { } while (0) /* * (puds are folded into p4ds so this doesn't get actually called, * but the define is needed for a generic inline function.)