diff options
Diffstat (limited to 'arch/x86/include/asm/pgtable.h')
| -rw-r--r-- | arch/x86/include/asm/pgtable.h | 1087 |
1 files changed, 794 insertions, 293 deletions
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 77037b6f1caa..e33df3da6980 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -1,6 +1,8 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_X86_PGTABLE_H #define _ASM_X86_PGTABLE_H +#include <linux/mem_encrypt.h> #include <asm/page.h> #include <asm/pgtable_types.h> @@ -13,16 +15,36 @@ cachemode2protval(_PAGE_CACHE_MODE_UC_MINUS))) \ : (prot)) -#ifndef __ASSEMBLY__ +#ifndef __ASSEMBLER__ +#include <linux/spinlock.h> #include <asm/x86_init.h> +#include <asm/pkru.h> +#include <asm/fpu/api.h> +#include <asm/coco.h> +#include <asm-generic/pgtable_uffd.h> +#include <linux/page_table_check.h> + +extern pgd_t early_top_pgt[PTRS_PER_PGD]; +bool __init __early_make_pgtable(unsigned long address, pmdval_t pmd); + +struct seq_file; +void ptdump_walk_pgd_level(struct seq_file *m, struct mm_struct *mm); +void ptdump_walk_pgd_level_debugfs(struct seq_file *m, struct mm_struct *mm, + bool user); +bool ptdump_walk_pgd_level_checkwx(void); +#define ptdump_check_wx ptdump_walk_pgd_level_checkwx +void ptdump_walk_user_pgd_level_checkwx(void); -void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd); -void ptdump_walk_pgd_level_checkwx(void); +/* + * Macros to add or remove encryption attribute + */ +#define pgprot_encrypted(prot) __pgprot(cc_mkenc(pgprot_val(prot))) +#define pgprot_decrypted(prot) __pgprot(cc_mkdec(pgprot_val(prot))) #ifdef CONFIG_DEBUG_WX -#define debug_checkwx() ptdump_walk_pgd_level_checkwx() +#define debug_checkwx_user() ptdump_walk_user_pgd_level_checkwx() #else -#define debug_checkwx() do { } while (0) +#define debug_checkwx_user() do { } while (0) #endif /* @@ -31,20 +53,19 @@ void ptdump_walk_pgd_level_checkwx(void); */ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __visible; -#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page)) +#define ZERO_PAGE(vaddr) ((void)(vaddr),virt_to_page(empty_zero_page)) extern spinlock_t pgd_lock; extern struct list_head pgd_list; extern struct mm_struct *pgd_page_get_mm(struct page *page); -#ifdef CONFIG_PARAVIRT +extern pmdval_t early_pmd_flags; + +#ifdef CONFIG_PARAVIRT_XXL #include <asm/paravirt.h> -#else /* !CONFIG_PARAVIRT */ +#else /* !CONFIG_PARAVIRT_XXL */ #define set_pte(ptep, pte) native_set_pte(ptep, pte) -#define set_pte_at(mm, addr, ptep, pte) native_set_pte_at(mm, addr, ptep, pte) -#define set_pmd_at(mm, addr, pmdp, pmd) native_set_pmd_at(mm, addr, pmdp, pmd) -#define set_pud_at(mm, addr, pudp, pud) native_set_pud_at(mm, addr, pudp, pud) #define set_pte_atomic(ptep, pte) \ native_set_pte_atomic(ptep, pte) @@ -53,7 +74,7 @@ extern struct mm_struct *pgd_page_get_mm(struct page *page); #ifndef __PAGETABLE_P4D_FOLDED #define set_pgd(pgdp, pgd) native_set_pgd(pgdp, pgd) -#define pgd_clear(pgd) native_pgd_clear(pgd) +#define pgd_clear(pgd) (pgtable_l5_enabled() ? native_pgd_clear(pgd) : 0) #endif #ifndef set_p4d @@ -75,8 +96,6 @@ extern struct mm_struct *pgd_page_get_mm(struct page *page); #define pte_clear(mm, addr, ptep) native_pte_clear(mm, addr, ptep) #define pmd_clear(pmd) native_pmd_clear(pmd) -#define pte_update(mm, addr, ptep) do { } while (0) - #define pgd_val(x) native_pgd_val(x) #define __pgd(x) native_make_pgd(x) @@ -99,50 +118,83 @@ extern struct mm_struct *pgd_page_get_mm(struct page *page); #define __pte(x) native_make_pte(x) #define arch_end_context_switch(prev) do {} while(0) +#endif /* CONFIG_PARAVIRT_XXL */ + +static inline pmd_t pmd_set_flags(pmd_t pmd, pmdval_t set) +{ + pmdval_t v = native_pmd_val(pmd); + + return native_make_pmd(v | set); +} + +static inline pmd_t pmd_clear_flags(pmd_t pmd, pmdval_t clear) +{ + pmdval_t v = native_pmd_val(pmd); + + return native_make_pmd(v & ~clear); +} + +static inline pud_t pud_set_flags(pud_t pud, pudval_t set) +{ + pudval_t v = native_pud_val(pud); -#endif /* CONFIG_PARAVIRT */ + return native_make_pud(v | set); +} + +static inline pud_t pud_clear_flags(pud_t pud, pudval_t clear) +{ + pudval_t v = native_pud_val(pud); + + return native_make_pud(v & ~clear); +} /* * The following only work if pte_present() is true. * Undefined behaviour if not.. */ -static inline int pte_dirty(pte_t pte) +static inline bool pte_dirty(pte_t pte) { - return pte_flags(pte) & _PAGE_DIRTY; + return pte_flags(pte) & _PAGE_DIRTY_BITS; } +static inline bool pte_shstk(pte_t pte) +{ + return cpu_feature_enabled(X86_FEATURE_SHSTK) && + (pte_flags(pte) & (_PAGE_RW | _PAGE_DIRTY)) == _PAGE_DIRTY; +} -static inline u32 read_pkru(void) +static inline int pte_young(pte_t pte) { - if (boot_cpu_has(X86_FEATURE_OSPKE)) - return __read_pkru(); - return 0; + return pte_flags(pte) & _PAGE_ACCESSED; } -static inline void write_pkru(u32 pkru) +static inline bool pte_decrypted(pte_t pte) { - if (boot_cpu_has(X86_FEATURE_OSPKE)) - __write_pkru(pkru); + return cc_mkdec(pte_val(pte)) == pte_val(pte); } -static inline int pte_young(pte_t pte) +#define pmd_dirty pmd_dirty +static inline bool pmd_dirty(pmd_t pmd) { - return pte_flags(pte) & _PAGE_ACCESSED; + return pmd_flags(pmd) & _PAGE_DIRTY_BITS; } -static inline int pmd_dirty(pmd_t pmd) +static inline bool pmd_shstk(pmd_t pmd) { - return pmd_flags(pmd) & _PAGE_DIRTY; + return cpu_feature_enabled(X86_FEATURE_SHSTK) && + (pmd_flags(pmd) & (_PAGE_RW | _PAGE_DIRTY | _PAGE_PSE)) == + (_PAGE_DIRTY | _PAGE_PSE); } +#define pmd_young pmd_young static inline int pmd_young(pmd_t pmd) { return pmd_flags(pmd) & _PAGE_ACCESSED; } -static inline int pud_dirty(pud_t pud) +static inline bool pud_dirty(pud_t pud) { - return pud_flags(pud) & _PAGE_DIRTY; + return pud_flags(pud) & _PAGE_DIRTY_BITS; } static inline int pud_young(pud_t pud) @@ -150,9 +202,36 @@ static inline int pud_young(pud_t pud) return pud_flags(pud) & _PAGE_ACCESSED; } +static inline bool pud_shstk(pud_t pud) +{ + return cpu_feature_enabled(X86_FEATURE_SHSTK) && + (pud_flags(pud) & (_PAGE_RW | _PAGE_DIRTY | _PAGE_PSE)) == + (_PAGE_DIRTY | _PAGE_PSE); +} + static inline int pte_write(pte_t pte) { - return pte_flags(pte) & _PAGE_RW; + /* + * Shadow stack pages are logically writable, but do not have + * _PAGE_RW. Check for them separately from _PAGE_RW itself. + */ + return (pte_flags(pte) & _PAGE_RW) || pte_shstk(pte); +} + +#define pmd_write pmd_write +static inline int pmd_write(pmd_t pmd) +{ + /* + * Shadow stack pages are logically writable, but do not have + * _PAGE_RW. Check for them separately from _PAGE_RW itself. + */ + return (pmd_flags(pmd) & _PAGE_RW) || pmd_shstk(pmd); +} + +#define pud_write pud_write +static inline int pud_write(pud_t pud) +{ + return pud_flags(pud) & _PAGE_RW; } static inline int pte_huge(pte_t pte) @@ -175,19 +254,32 @@ static inline int pte_special(pte_t pte) return pte_flags(pte) & _PAGE_SPECIAL; } +/* Entries that were set to PROT_NONE are inverted */ + +static inline u64 protnone_mask(u64 val); + +#define PFN_PTE_SHIFT PAGE_SHIFT + static inline unsigned long pte_pfn(pte_t pte) { - return (pte_val(pte) & PTE_PFN_MASK) >> PAGE_SHIFT; + phys_addr_t pfn = pte_val(pte); + pfn ^= protnone_mask(pfn); + return (pfn & PTE_PFN_MASK) >> PAGE_SHIFT; } static inline unsigned long pmd_pfn(pmd_t pmd) { - return (pmd_val(pmd) & pmd_pfn_mask(pmd)) >> PAGE_SHIFT; + phys_addr_t pfn = pmd_val(pmd); + pfn ^= protnone_mask(pfn); + return (pfn & pmd_pfn_mask(pmd)) >> PAGE_SHIFT; } +#define pud_pfn pud_pfn static inline unsigned long pud_pfn(pud_t pud) { - return (pud_val(pud) & pud_pfn_mask(pud)) >> PAGE_SHIFT; + phys_addr_t pfn = pud_val(pud); + pfn ^= protnone_mask(pfn); + return (pfn & pud_pfn_mask(pud)) >> PAGE_SHIFT; } static inline unsigned long p4d_pfn(p4d_t p4d) @@ -195,15 +287,15 @@ static inline unsigned long p4d_pfn(p4d_t p4d) return (p4d_val(p4d) & p4d_pfn_mask(p4d)) >> PAGE_SHIFT; } -static inline int p4d_large(p4d_t p4d) +static inline unsigned long pgd_pfn(pgd_t pgd) { - /* No 512 GiB pages yet */ - return 0; + return (pgd_val(pgd) & PTE_PFN_MASK) >> PAGE_SHIFT; } #define pte_page(pte) pfn_to_page(pte_pfn(pte)) -static inline int pmd_large(pmd_t pte) +#define pmd_leaf pmd_leaf +static inline bool pmd_leaf(pmd_t pte) { return pmd_flags(pte) & _PAGE_PSE; } @@ -211,13 +303,13 @@ static inline int pmd_large(pmd_t pte) #ifdef CONFIG_TRANSPARENT_HUGEPAGE static inline int pmd_trans_huge(pmd_t pmd) { - return (pmd_val(pmd) & (_PAGE_PSE|_PAGE_DEVMAP)) == _PAGE_PSE; + return (pmd_val(pmd) & _PAGE_PSE) == _PAGE_PSE; } #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD static inline int pud_trans_huge(pud_t pud) { - return (pud_val(pud) & (_PAGE_PSE|_PAGE_DEVMAP)) == _PAGE_PSE; + return (pud_val(pud) & _PAGE_PSE) == _PAGE_PSE; } #endif @@ -227,29 +319,29 @@ static inline int has_transparent_hugepage(void) return boot_cpu_has(X86_FEATURE_PSE); } -#ifdef __HAVE_ARCH_PTE_DEVMAP -static inline int pmd_devmap(pmd_t pmd) +#ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP +static inline bool pmd_special(pmd_t pmd) { - return !!(pmd_val(pmd) & _PAGE_DEVMAP); + return pmd_flags(pmd) & _PAGE_SPECIAL; } -#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD -static inline int pud_devmap(pud_t pud) +static inline pmd_t pmd_mkspecial(pmd_t pmd) { - return !!(pud_val(pud) & _PAGE_DEVMAP); + return pmd_set_flags(pmd, _PAGE_SPECIAL); } -#else -static inline int pud_devmap(pud_t pud) +#endif /* CONFIG_ARCH_SUPPORTS_PMD_PFNMAP */ + +#ifdef CONFIG_ARCH_SUPPORTS_PUD_PFNMAP +static inline bool pud_special(pud_t pud) { - return 0; + return pud_flags(pud) & _PAGE_SPECIAL; } -#endif -static inline int pgd_devmap(pgd_t pgd) +static inline pud_t pud_mkspecial(pud_t pud) { - return 0; + return pud_set_flags(pud, _PAGE_SPECIAL); } -#endif +#endif /* CONFIG_ARCH_SUPPORTS_PUD_PFNMAP */ #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ static inline pte_t pte_set_flags(pte_t pte, pteval_t set) @@ -266,19 +358,90 @@ static inline pte_t pte_clear_flags(pte_t pte, pteval_t clear) return native_make_pte(v & ~clear); } -static inline pte_t pte_mkclean(pte_t pte) +/* + * Write protection operations can result in Dirty=1,Write=0 PTEs. But in the + * case of X86_FEATURE_USER_SHSTK, these PTEs denote shadow stack memory. So + * when creating dirty, write-protected memory, a software bit is used: + * _PAGE_BIT_SAVED_DIRTY. The following functions take a PTE and transition the + * Dirty bit to SavedDirty, and vice-vesra. + * + * This shifting is only done if needed. In the case of shifting + * Dirty->SavedDirty, the condition is if the PTE is Write=0. In the case of + * shifting SavedDirty->Dirty, the condition is Write=1. + */ +static inline pgprotval_t mksaveddirty_shift(pgprotval_t v) { - return pte_clear_flags(pte, _PAGE_DIRTY); + pgprotval_t cond = (~v >> _PAGE_BIT_RW) & 1; + + v |= ((v >> _PAGE_BIT_DIRTY) & cond) << _PAGE_BIT_SAVED_DIRTY; + v &= ~(cond << _PAGE_BIT_DIRTY); + + return v; } -static inline pte_t pte_mkold(pte_t pte) +static inline pgprotval_t clear_saveddirty_shift(pgprotval_t v) { - return pte_clear_flags(pte, _PAGE_ACCESSED); + pgprotval_t cond = (v >> _PAGE_BIT_RW) & 1; + + v |= ((v >> _PAGE_BIT_SAVED_DIRTY) & cond) << _PAGE_BIT_DIRTY; + v &= ~(cond << _PAGE_BIT_SAVED_DIRTY); + + return v; +} + +static inline pte_t pte_mksaveddirty(pte_t pte) +{ + pteval_t v = native_pte_val(pte); + + v = mksaveddirty_shift(v); + return native_make_pte(v); +} + +static inline pte_t pte_clear_saveddirty(pte_t pte) +{ + pteval_t v = native_pte_val(pte); + + v = clear_saveddirty_shift(v); + return native_make_pte(v); } static inline pte_t pte_wrprotect(pte_t pte) { - return pte_clear_flags(pte, _PAGE_RW); + pte = pte_clear_flags(pte, _PAGE_RW); + + /* + * Blindly clearing _PAGE_RW might accidentally create + * a shadow stack PTE (Write=0,Dirty=1). Move the hardware + * dirty value to the software bit, if present. + */ + return pte_mksaveddirty(pte); +} + +#ifdef CONFIG_HAVE_ARCH_USERFAULTFD_WP +static inline int pte_uffd_wp(pte_t pte) +{ + return pte_flags(pte) & _PAGE_UFFD_WP; +} + +static inline pte_t pte_mkuffd_wp(pte_t pte) +{ + return pte_wrprotect(pte_set_flags(pte, _PAGE_UFFD_WP)); +} + +static inline pte_t pte_clear_uffd_wp(pte_t pte) +{ + return pte_clear_flags(pte, _PAGE_UFFD_WP); +} +#endif /* CONFIG_HAVE_ARCH_USERFAULTFD_WP */ + +static inline pte_t pte_mkclean(pte_t pte) +{ + return pte_clear_flags(pte, _PAGE_DIRTY_BITS); +} + +static inline pte_t pte_mkold(pte_t pte) +{ + return pte_clear_flags(pte, _PAGE_ACCESSED); } static inline pte_t pte_mkexec(pte_t pte) @@ -288,7 +451,16 @@ static inline pte_t pte_mkexec(pte_t pte) static inline pte_t pte_mkdirty(pte_t pte) { - return pte_set_flags(pte, _PAGE_DIRTY | _PAGE_SOFT_DIRTY); + pte = pte_set_flags(pte, _PAGE_DIRTY | _PAGE_SOFT_DIRTY); + + return pte_mksaveddirty(pte); +} + +static inline pte_t pte_mkwrite_shstk(pte_t pte) +{ + pte = pte_clear_flags(pte, _PAGE_RW); + + return pte_set_flags(pte, _PAGE_DIRTY); } static inline pte_t pte_mkyoung(pte_t pte) @@ -296,11 +468,15 @@ static inline pte_t pte_mkyoung(pte_t pte) return pte_set_flags(pte, _PAGE_ACCESSED); } -static inline pte_t pte_mkwrite(pte_t pte) +static inline pte_t pte_mkwrite_novma(pte_t pte) { return pte_set_flags(pte, _PAGE_RW); } +struct vm_area_struct; +pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma); +#define pte_mkwrite pte_mkwrite + static inline pte_t pte_mkhuge(pte_t pte) { return pte_set_flags(pte, _PAGE_PSE); @@ -326,48 +502,75 @@ static inline pte_t pte_mkspecial(pte_t pte) return pte_set_flags(pte, _PAGE_SPECIAL); } -static inline pte_t pte_mkdevmap(pte_t pte) +/* See comments above mksaveddirty_shift() */ +static inline pmd_t pmd_mksaveddirty(pmd_t pmd) { - return pte_set_flags(pte, _PAGE_SPECIAL|_PAGE_DEVMAP); + pmdval_t v = native_pmd_val(pmd); + + v = mksaveddirty_shift(v); + return native_make_pmd(v); } -static inline pmd_t pmd_set_flags(pmd_t pmd, pmdval_t set) +/* See comments above mksaveddirty_shift() */ +static inline pmd_t pmd_clear_saveddirty(pmd_t pmd) { pmdval_t v = native_pmd_val(pmd); - return __pmd(v | set); + v = clear_saveddirty_shift(v); + return native_make_pmd(v); } -static inline pmd_t pmd_clear_flags(pmd_t pmd, pmdval_t clear) +static inline pmd_t pmd_wrprotect(pmd_t pmd) { - pmdval_t v = native_pmd_val(pmd); + pmd = pmd_clear_flags(pmd, _PAGE_RW); - return __pmd(v & ~clear); + /* + * Blindly clearing _PAGE_RW might accidentally create + * a shadow stack PMD (RW=0, Dirty=1). Move the hardware + * dirty value to the software bit. + */ + return pmd_mksaveddirty(pmd); } -static inline pmd_t pmd_mkold(pmd_t pmd) +#ifdef CONFIG_HAVE_ARCH_USERFAULTFD_WP +static inline int pmd_uffd_wp(pmd_t pmd) { - return pmd_clear_flags(pmd, _PAGE_ACCESSED); + return pmd_flags(pmd) & _PAGE_UFFD_WP; } -static inline pmd_t pmd_mkclean(pmd_t pmd) +static inline pmd_t pmd_mkuffd_wp(pmd_t pmd) { - return pmd_clear_flags(pmd, _PAGE_DIRTY); + return pmd_wrprotect(pmd_set_flags(pmd, _PAGE_UFFD_WP)); } -static inline pmd_t pmd_wrprotect(pmd_t pmd) +static inline pmd_t pmd_clear_uffd_wp(pmd_t pmd) +{ + return pmd_clear_flags(pmd, _PAGE_UFFD_WP); +} +#endif /* CONFIG_HAVE_ARCH_USERFAULTFD_WP */ + +static inline pmd_t pmd_mkold(pmd_t pmd) +{ + return pmd_clear_flags(pmd, _PAGE_ACCESSED); +} + +static inline pmd_t pmd_mkclean(pmd_t pmd) { - return pmd_clear_flags(pmd, _PAGE_RW); + return pmd_clear_flags(pmd, _PAGE_DIRTY_BITS); } static inline pmd_t pmd_mkdirty(pmd_t pmd) { - return pmd_set_flags(pmd, _PAGE_DIRTY | _PAGE_SOFT_DIRTY); + pmd = pmd_set_flags(pmd, _PAGE_DIRTY | _PAGE_SOFT_DIRTY); + + return pmd_mksaveddirty(pmd); } -static inline pmd_t pmd_mkdevmap(pmd_t pmd) +static inline pmd_t pmd_mkwrite_shstk(pmd_t pmd) { - return pmd_set_flags(pmd, _PAGE_DEVMAP); + pmd = pmd_clear_flags(pmd, _PAGE_RW); + + return pmd_set_flags(pmd, _PAGE_DIRTY); } static inline pmd_t pmd_mkhuge(pmd_t pmd) @@ -380,28 +583,30 @@ static inline pmd_t pmd_mkyoung(pmd_t pmd) return pmd_set_flags(pmd, _PAGE_ACCESSED); } -static inline pmd_t pmd_mkwrite(pmd_t pmd) +static inline pmd_t pmd_mkwrite_novma(pmd_t pmd) { return pmd_set_flags(pmd, _PAGE_RW); } -static inline pmd_t pmd_mknotpresent(pmd_t pmd) -{ - return pmd_clear_flags(pmd, _PAGE_PRESENT | _PAGE_PROTNONE); -} +pmd_t pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma); +#define pmd_mkwrite pmd_mkwrite -static inline pud_t pud_set_flags(pud_t pud, pudval_t set) +/* See comments above mksaveddirty_shift() */ +static inline pud_t pud_mksaveddirty(pud_t pud) { pudval_t v = native_pud_val(pud); - return __pud(v | set); + v = mksaveddirty_shift(v); + return native_make_pud(v); } -static inline pud_t pud_clear_flags(pud_t pud, pudval_t clear) +/* See comments above mksaveddirty_shift() */ +static inline pud_t pud_clear_saveddirty(pud_t pud) { pudval_t v = native_pud_val(pud); - return __pud(v & ~clear); + v = clear_saveddirty_shift(v); + return native_make_pud(v); } static inline pud_t pud_mkold(pud_t pud) @@ -411,22 +616,26 @@ static inline pud_t pud_mkold(pud_t pud) static inline pud_t pud_mkclean(pud_t pud) { - return pud_clear_flags(pud, _PAGE_DIRTY); + return pud_clear_flags(pud, _PAGE_DIRTY_BITS); } static inline pud_t pud_wrprotect(pud_t pud) { - return pud_clear_flags(pud, _PAGE_RW); + pud = pud_clear_flags(pud, _PAGE_RW); + + /* + * Blindly clearing _PAGE_RW might accidentally create + * a shadow stack PUD (RW=0, Dirty=1). Move the hardware + * dirty value to the software bit. + */ + return pud_mksaveddirty(pud); } static inline pud_t pud_mkdirty(pud_t pud) { - return pud_set_flags(pud, _PAGE_DIRTY | _PAGE_SOFT_DIRTY); -} + pud = pud_set_flags(pud, _PAGE_DIRTY | _PAGE_SOFT_DIRTY); -static inline pud_t pud_mkdevmap(pud_t pud) -{ - return pud_set_flags(pud, _PAGE_DEVMAP); + return pud_mksaveddirty(pud); } static inline pud_t pud_mkhuge(pud_t pud) @@ -441,12 +650,9 @@ static inline pud_t pud_mkyoung(pud_t pud) static inline pud_t pud_mkwrite(pud_t pud) { - return pud_set_flags(pud, _PAGE_RW); -} + pud = pud_set_flags(pud, _PAGE_RW); -static inline pud_t pud_mknotpresent(pud_t pud) -{ - return pud_clear_flags(pud, _PAGE_PRESENT | _PAGE_PROTNONE); + return pud_clear_saveddirty(pud); } #ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY @@ -511,54 +717,152 @@ static inline pgprotval_t massage_pgprot(pgprot_t pgprot) return protval; } +static inline pgprotval_t check_pgprot(pgprot_t pgprot) +{ + pgprotval_t massaged_val = massage_pgprot(pgprot); + + /* mmdebug.h can not be included here because of dependencies */ +#ifdef CONFIG_DEBUG_VM + WARN_ONCE(pgprot_val(pgprot) != massaged_val, + "attempted to set unsupported pgprot: %016llx " + "bits: %016llx supported: %016llx\n", + (u64)pgprot_val(pgprot), + (u64)pgprot_val(pgprot) ^ massaged_val, + (u64)__supported_pte_mask); +#endif + + return massaged_val; +} + static inline pte_t pfn_pte(unsigned long page_nr, pgprot_t pgprot) { - return __pte(((phys_addr_t)page_nr << PAGE_SHIFT) | - massage_pgprot(pgprot)); + phys_addr_t pfn = (phys_addr_t)page_nr << PAGE_SHIFT; + /* This bit combination is used to mark shadow stacks */ + WARN_ON_ONCE((pgprot_val(pgprot) & (_PAGE_DIRTY | _PAGE_RW)) == + _PAGE_DIRTY); + pfn ^= protnone_mask(pgprot_val(pgprot)); + pfn &= PTE_PFN_MASK; + return __pte(pfn | check_pgprot(pgprot)); } static inline pmd_t pfn_pmd(unsigned long page_nr, pgprot_t pgprot) { - return __pmd(((phys_addr_t)page_nr << PAGE_SHIFT) | - massage_pgprot(pgprot)); + phys_addr_t pfn = (phys_addr_t)page_nr << PAGE_SHIFT; + pfn ^= protnone_mask(pgprot_val(pgprot)); + pfn &= PHYSICAL_PMD_PAGE_MASK; + return __pmd(pfn | check_pgprot(pgprot)); } static inline pud_t pfn_pud(unsigned long page_nr, pgprot_t pgprot) { - return __pud(((phys_addr_t)page_nr << PAGE_SHIFT) | - massage_pgprot(pgprot)); + phys_addr_t pfn = (phys_addr_t)page_nr << PAGE_SHIFT; + pfn ^= protnone_mask(pgprot_val(pgprot)); + pfn &= PHYSICAL_PUD_PAGE_MASK; + return __pud(pfn | check_pgprot(pgprot)); +} + +static inline pmd_t pmd_mkinvalid(pmd_t pmd) +{ + return pfn_pmd(pmd_pfn(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) { - pteval_t val = pte_val(pte); + pteval_t val = pte_val(pte), oldval = val; + pte_t pte_result; /* * Chop off the NX bit (if present), and add the NX portion of * the newprot (if present): */ val &= _PAGE_CHG_MASK; - val |= massage_pgprot(newprot) & ~_PAGE_CHG_MASK; + val |= check_pgprot(newprot) & ~_PAGE_CHG_MASK; + val = flip_protnone_guard(oldval, val, PTE_PFN_MASK); + + pte_result = __pte(val); + + /* + * To avoid creating Write=0,Dirty=1 PTEs, pte_modify() needs to avoid: + * 1. Marking Write=0 PTEs Dirty=1 + * 2. Marking Dirty=1 PTEs 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. + */ + if (oldval & _PAGE_RW) + pte_result = pte_mksaveddirty(pte_result); + else + pte_result = pte_clear_saveddirty(pte_result); - return __pte(val); + return pte_result; } static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) { - pmdval_t val = pmd_val(pmd); + pmdval_t val = pmd_val(pmd), oldval = val; + pmd_t pmd_result; + + val &= (_HPAGE_CHG_MASK & ~_PAGE_DIRTY); + val |= check_pgprot(newprot) & ~_HPAGE_CHG_MASK; + val = flip_protnone_guard(oldval, val, PHYSICAL_PMD_PAGE_MASK); + + pmd_result = __pmd(val); + + /* + * Avoid creating shadow stack PMD by accident. See comment in + * pte_modify(). + */ + if (oldval & _PAGE_RW) + pmd_result = pmd_mksaveddirty(pmd_result); + else + pmd_result = pmd_clear_saveddirty(pmd_result); + + 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 |= massage_pgprot(newprot) & ~_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 __pmd(val); + return pud_result; } -/* mprotect needs to preserve PAT bits when updating vm_page_prot */ +/* + * mprotect needs to preserve PAT and encryption bits when updating + * vm_page_prot + */ #define pgprot_modify pgprot_modify static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot) { pgprotval_t preservebits = pgprot_val(oldprot) & _PAGE_CHG_MASK; - pgprotval_t addbits = pgprot_val(newprot); + pgprotval_t addbits = pgprot_val(newprot) & ~_PAGE_CHG_MASK; return __pgprot(preservebits | addbits); } @@ -603,7 +907,30 @@ static inline int is_new_memtype_allowed(u64 paddr, unsigned long size, pmd_t *populate_extra_pmd(unsigned long vaddr); pte_t *populate_extra_pte(unsigned long vaddr); -#endif /* __ASSEMBLY__ */ + +#ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION +pgd_t __pti_set_user_pgtbl(pgd_t *pgdp, pgd_t pgd); + +/* + * Take a PGD location (pgdp) and a pgd value that needs to be set there. + * Populates the user and returns the resulting PGD that must be set in + * the kernel copy of the page tables. + */ +static inline pgd_t pti_set_user_pgtbl(pgd_t *pgdp, pgd_t pgd) +{ + if (!static_cpu_has(X86_FEATURE_PTI)) + return pgd; + return __pti_set_user_pgtbl(pgdp, pgd); +} +#else /* CONFIG_MITIGATION_PAGE_TABLE_ISOLATION */ +static inline pgd_t pti_set_user_pgtbl(pgd_t *pgdp, pgd_t pgd) +{ + return pgd; +} +#endif /* CONFIG_MITIGATION_PAGE_TABLE_ISOLATION */ + +#endif /* __ASSEMBLER__ */ + #ifdef CONFIG_X86_32 # include <asm/pgtable_32.h> @@ -611,7 +938,7 @@ pte_t *populate_extra_pte(unsigned long vaddr); # include <asm/pgtable_64.h> #endif -#ifndef __ASSEMBLY__ +#ifndef __ASSEMBLER__ #include <linux/mm_types.h> #include <linux/mmdebug.h> #include <linux/log2.h> @@ -628,17 +955,18 @@ static inline int pte_same(pte_t a, pte_t b) return a.pte == b.pte; } -static inline int pte_present(pte_t a) +static inline pte_t pte_advance_pfn(pte_t pte, unsigned long nr) { - return pte_flags(a) & (_PAGE_PRESENT | _PAGE_PROTNONE); + if (__pte_needs_invert(pte_val(pte))) + return __pte(pte_val(pte) - (nr << PFN_PTE_SHIFT)); + return __pte(pte_val(pte) + (nr << PFN_PTE_SHIFT)); } +#define pte_advance_pfn pte_advance_pfn -#ifdef __HAVE_ARCH_PTE_DEVMAP -static inline int pte_devmap(pte_t a) +static inline int pte_present(pte_t a) { - return (pte_flags(a) & _PAGE_DEVMAP) == _PAGE_DEVMAP; + return pte_flags(a) & (_PAGE_PRESENT | _PAGE_PROTNONE); } -#endif #define pte_accessible pte_accessible static inline bool pte_accessible(struct mm_struct *mm, pte_t a) @@ -647,17 +975,12 @@ static inline bool pte_accessible(struct mm_struct *mm, pte_t a) return true; if ((pte_flags(a) & _PAGE_PROTNONE) && - mm_tlb_flush_pending(mm)) + atomic_read(&mm->tlb_flush_pending)) return true; return false; } -static inline int pte_hidden(pte_t pte) -{ - return pte_flags(pte) & _PAGE_HIDDEN; -} - static inline int pmd_present(pmd_t pmd) { /* @@ -672,7 +995,7 @@ static inline int pmd_present(pmd_t pmd) #ifdef CONFIG_NUMA_BALANCING /* * These work without NUMA balancing but the kernel does not care. See the - * comment in include/asm-generic/pgtable.h + * comment in include/linux/pgtable.h */ static inline int pte_protnone(pte_t pte) { @@ -704,48 +1027,12 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd) * Currently stuck as a macro due to indirect forward reference to * linux/mmzone.h's __section_mem_map_addr() definition: */ -#define pmd_page(pmd) \ - pfn_to_page((pmd_val(pmd) & pmd_pfn_mask(pmd)) >> PAGE_SHIFT) - -/* - * the pmd page can be thought of an array like this: pmd_t[PTRS_PER_PMD] - * - * this macro returns the index of the entry in the pmd page which would - * control the given virtual address - */ -static inline unsigned long pmd_index(unsigned long address) -{ - return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1); -} - -/* - * Conversion functions: convert a page and protection to a page entry, - * and a page entry and page directory to the page they refer to. - * - * (Currently stuck as a macro because of indirect forward reference - * to linux/mm.h:page_to_nid()) - */ -#define mk_pte(page, pgprot) pfn_pte(page_to_pfn(page), (pgprot)) - -/* - * the pte page can be thought of an array like this: pte_t[PTRS_PER_PTE] - * - * this function returns the index of the entry in the pte page which would - * control the given virtual address - */ -static inline unsigned long pte_index(unsigned long address) -{ - return (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1); -} - -static inline pte_t *pte_offset_kernel(pmd_t *pmd, unsigned long address) -{ - return (pte_t *)pmd_page_vaddr(*pmd) + pte_index(address); -} +#define pmd_page(pmd) pfn_to_page(pmd_pfn(pmd)) static inline int pmd_bad(pmd_t pmd) { - return (pmd_flags(pmd) & ~_PAGE_USER) != _KERNPG_TABLE; + return (pmd_flags(pmd) & ~(_PAGE_USER | _PAGE_ACCESSED)) != + (_KERNPG_TABLE & ~_PAGE_ACCESSED); } static inline unsigned long pages_to_mb(unsigned long npg) @@ -764,46 +1051,29 @@ static inline int pud_present(pud_t pud) return pud_flags(pud) & _PAGE_PRESENT; } -static inline unsigned long pud_page_vaddr(pud_t pud) +static inline pmd_t *pud_pgtable(pud_t pud) { - return (unsigned long)__va(pud_val(pud) & pud_pfn_mask(pud)); + return (pmd_t *)__va(pud_val(pud) & pud_pfn_mask(pud)); } /* * Currently stuck as a macro due to indirect forward reference to * linux/mmzone.h's __section_mem_map_addr() definition: */ -#define pud_page(pud) \ - pfn_to_page((pud_val(pud) & pud_pfn_mask(pud)) >> PAGE_SHIFT) +#define pud_page(pud) pfn_to_page(pud_pfn(pud)) -/* Find an entry in the second-level page table.. */ -static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address) +#define pud_leaf pud_leaf +static inline bool pud_leaf(pud_t pud) { - return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address); -} - -static inline int pud_large(pud_t pud) -{ - return (pud_val(pud) & (_PAGE_PSE | _PAGE_PRESENT)) == - (_PAGE_PSE | _PAGE_PRESENT); + return pud_val(pud) & _PAGE_PSE; } static inline int pud_bad(pud_t pud) { return (pud_flags(pud) & ~(_KERNPG_TABLE | _PAGE_USER)) != 0; } -#else -static inline int pud_large(pud_t pud) -{ - return 0; -} #endif /* CONFIG_PGTABLE_LEVELS > 2 */ -static inline unsigned long pud_index(unsigned long address) -{ - return (address >> PUD_SHIFT) & (PTRS_PER_PUD - 1); -} - #if CONFIG_PGTABLE_LEVELS > 3 static inline int p4d_none(p4d_t p4d) { @@ -815,27 +1085,25 @@ static inline int p4d_present(p4d_t p4d) return p4d_flags(p4d) & _PAGE_PRESENT; } -static inline unsigned long p4d_page_vaddr(p4d_t p4d) +static inline pud_t *p4d_pgtable(p4d_t p4d) { - return (unsigned long)__va(p4d_val(p4d) & p4d_pfn_mask(p4d)); + return (pud_t *)__va(p4d_val(p4d) & p4d_pfn_mask(p4d)); } /* * Currently stuck as a macro due to indirect forward reference to * linux/mmzone.h's __section_mem_map_addr() definition: */ -#define p4d_page(p4d) \ - pfn_to_page((p4d_val(p4d) & p4d_pfn_mask(p4d)) >> PAGE_SHIFT) - -/* Find an entry in the third-level page table.. */ -static inline pud_t *pud_offset(p4d_t *p4d, unsigned long address) -{ - return (pud_t *)p4d_page_vaddr(*p4d) + pud_index(address); -} +#define p4d_page(p4d) pfn_to_page(p4d_pfn(p4d)) static inline int p4d_bad(p4d_t p4d) { - return (p4d_flags(p4d) & ~(_KERNPG_TABLE | _PAGE_USER)) != 0; + unsigned long ignore_flags = _KERNPG_TABLE | _PAGE_USER; + + if (IS_ENABLED(CONFIG_MITIGATION_PAGE_TABLE_ISOLATION)) + ignore_flags |= _PAGE_NX; + + return (p4d_flags(p4d) & ~ignore_flags) != 0; } #endif /* CONFIG_PGTABLE_LEVELS > 3 */ @@ -847,6 +1115,8 @@ static inline unsigned long p4d_index(unsigned long address) #if CONFIG_PGTABLE_LEVELS > 4 static inline int pgd_present(pgd_t pgd) { + if (!pgtable_l5_enabled()) + return 1; return pgd_flags(pgd) & _PAGE_PRESENT; } @@ -859,21 +1129,33 @@ static inline unsigned long pgd_page_vaddr(pgd_t pgd) * Currently stuck as a macro due to indirect forward reference to * linux/mmzone.h's __section_mem_map_addr() definition: */ -#define pgd_page(pgd) pfn_to_page(pgd_val(pgd) >> PAGE_SHIFT) +#define pgd_page(pgd) pfn_to_page(pgd_pfn(pgd)) /* to find an entry in a page-table-directory. */ static inline p4d_t *p4d_offset(pgd_t *pgd, unsigned long address) { + if (!pgtable_l5_enabled()) + return (p4d_t *)pgd; return (p4d_t *)pgd_page_vaddr(*pgd) + p4d_index(address); } static inline int pgd_bad(pgd_t pgd) { - return (pgd_flags(pgd) & ~_PAGE_USER) != _KERNPG_TABLE; + unsigned long ignore_flags = _PAGE_USER; + + if (!pgtable_l5_enabled()) + return 0; + + if (IS_ENABLED(CONFIG_MITIGATION_PAGE_TABLE_ISOLATION)) + ignore_flags |= _PAGE_NX; + + return (pgd_flags(pgd) & ~ignore_flags) != _KERNPG_TABLE; } static inline int pgd_none(pgd_t pgd) { + if (!pgtable_l5_enabled()) + return 0; /* * There is no need to do a workaround for the KNL stray * A/D bit erratum here. PGDs only point to page tables @@ -884,53 +1166,22 @@ static inline int pgd_none(pgd_t pgd) } #endif /* CONFIG_PGTABLE_LEVELS > 4 */ -#endif /* __ASSEMBLY__ */ - -/* - * the pgd page can be thought of an array like this: pgd_t[PTRS_PER_PGD] - * - * this macro returns the index of the entry in the pgd page which would - * control the given virtual address - */ -#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1)) - -/* - * pgd_offset() returns a (pgd_t *) - * pgd_index() is used get the offset into the pgd page's array of pgd_t's; - */ -#define pgd_offset(mm, address) ((mm)->pgd + pgd_index((address))) -/* - * a shortcut which implies the use of the kernel's pgd, instead - * of a process's - */ -#define pgd_offset_k(address) pgd_offset(&init_mm, (address)) - +#endif /* __ASSEMBLER__ */ #define KERNEL_PGD_BOUNDARY pgd_index(PAGE_OFFSET) #define KERNEL_PGD_PTRS (PTRS_PER_PGD - KERNEL_PGD_BOUNDARY) -#ifndef __ASSEMBLY__ +#ifndef __ASSEMBLER__ extern int direct_gbpages; void init_mem_mapping(void); void early_alloc_pgt_buf(void); -extern void memblock_find_dma_reserve(void); +void __init poking_init(void); +unsigned long init_memory_mapping(unsigned long start, + unsigned long end, pgprot_t prot); #ifdef CONFIG_X86_64 -/* Realmode trampoline initialization. */ extern pgd_t trampoline_pgd_entry; -static inline void __meminit init_trampoline_default(void) -{ - /* Default trampoline pgd value */ - trampoline_pgd_entry = init_top_pgt[pgd_index(__PAGE_OFFSET)]; -} -# ifdef CONFIG_RANDOMIZE_MEMORY -void __meminit init_trampoline(void); -# else -# define init_trampoline init_trampoline_default -# endif -#else -static inline void init_trampoline(void) { } #endif /* local pte updates need not use xchg for locking */ @@ -959,37 +1210,20 @@ static inline pud_t native_local_pudp_get_and_clear(pud_t *pudp) return res; } -static inline void native_set_pte_at(struct mm_struct *mm, unsigned long addr, - pte_t *ptep , pte_t pte) -{ - native_set_pte(ptep, pte); -} - -static inline void native_set_pmd_at(struct mm_struct *mm, unsigned long addr, - pmd_t *pmdp , pmd_t pmd) +static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr, + pmd_t *pmdp, pmd_t pmd) { - native_set_pmd(pmdp, pmd); + page_table_check_pmd_set(mm, pmdp, pmd); + set_pmd(pmdp, pmd); } -static inline void native_set_pud_at(struct mm_struct *mm, unsigned long addr, - pud_t *pudp, pud_t pud) +static inline void set_pud_at(struct mm_struct *mm, unsigned long addr, + pud_t *pudp, pud_t pud) { + page_table_check_pud_set(mm, pudp, pud); native_set_pud(pudp, pud); } -#ifndef CONFIG_PARAVIRT -/* - * Rules for using pte_update - it must be called after any PTE update which - * has not been done using the set_pte / clear_pte interfaces. It is used by - * shadow mode hypervisors to resynchronize the shadow page tables. Kernel PTE - * updates should either be sets, clears, or set_pte_atomic for P->P - * transitions, which means this hook should only be called for user PTEs. - * This hook implies a P->P protection or access change has taken place, which - * requires a subsequent TLB flush. - */ -#define pte_update(mm, addr, ptep) do { } while (0) -#endif - /* * We only update the dirty/accessed state if we set * the dirty bit by hand in the kernel, since the hardware @@ -1017,7 +1251,7 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { pte_t pte = native_ptep_get_and_clear(ptep); - pte_update(mm, addr, ptep); + page_table_check_pte_clear(mm, pte); return pte; } @@ -1033,6 +1267,7 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm, * care about updates and native needs no locking */ pte = native_local_ptep_get_and_clear(ptep); + page_table_check_pte_clear(mm, pte); } else { pte = ptep_get_and_clear(mm, addr, ptep); } @@ -1043,13 +1278,20 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm, static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { - clear_bit(_PAGE_BIT_RW, (unsigned long *)&ptep->pte); - pte_update(mm, addr, ptep); -} + /* + * Avoid accidentally creating shadow stack PTEs + * (Write=0,Dirty=1). Use cmpxchg() to prevent races with + * the hardware setting Dirty=1. + */ + pte_t old_pte, new_pte; -#define flush_tlb_fix_spurious_fault(vma, address) do { } while (0) + old_pte = READ_ONCE(*ptep); + do { + new_pte = pte_wrprotect(old_pte); + } while (!try_cmpxchg((long *)&ptep->pte, (long *)&old_pte, *(long *)&new_pte)); +} -#define mk_pmd(page, pgprot) pfn_pmd(page_to_pfn(page), (pgprot)) +#define flush_tlb_fix_spurious_fault(vma, address, ptep) do { } while (0) #define __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS extern int pmdp_set_access_flags(struct vm_area_struct *vma, @@ -1070,37 +1312,150 @@ extern int pmdp_clear_flush_young(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp); -#define __HAVE_ARCH_PMD_WRITE -static inline int pmd_write(pmd_t pmd) -{ - return pmd_flags(pmd) & _PAGE_RW; -} - #define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, unsigned long addr, pmd_t *pmdp) { - return native_pmdp_get_and_clear(pmdp); + pmd_t pmd = native_pmdp_get_and_clear(pmdp); + + page_table_check_pmd_clear(mm, pmd); + + return pmd; } #define __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm, unsigned long addr, pud_t *pudp) { - return native_pudp_get_and_clear(pudp); + pud_t pud = native_pudp_get_and_clear(pudp); + + page_table_check_pud_clear(mm, pud); + + return pud; } #define __HAVE_ARCH_PMDP_SET_WRPROTECT static inline void pmdp_set_wrprotect(struct mm_struct *mm, unsigned long addr, pmd_t *pmdp) { - clear_bit(_PAGE_BIT_RW, (unsigned long *)pmdp); + /* + * Avoid accidentally creating shadow stack PTEs + * (Write=0,Dirty=1). Use cmpxchg() to prevent races with + * the hardware setting Dirty=1. + */ + pmd_t old_pmd, new_pmd; + + old_pmd = READ_ONCE(*pmdp); + do { + new_pmd = pmd_wrprotect(old_pmd); + } while (!try_cmpxchg((long *)pmdp, (long *)&old_pmd, *(long *)&new_pmd)); } +#ifndef pmdp_establish +#define pmdp_establish pmdp_establish +static inline pmd_t pmdp_establish(struct vm_area_struct *vma, + unsigned long address, pmd_t *pmdp, pmd_t pmd) +{ + page_table_check_pmd_set(vma->vm_mm, pmdp, pmd); + if (IS_ENABLED(CONFIG_SMP)) { + return xchg(pmdp, pmd); + } else { + pmd_t old = *pmdp; + WRITE_ONCE(*pmdp, pmd); + return old; + } +} +#endif + +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD +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; + } +} +#endif + +#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. + * + * Returns true for parts of the PGD that map userspace and + * false for the parts that map the kernel. + */ +static inline bool pgdp_maps_userspace(void *__ptr) +{ + unsigned long ptr = (unsigned long)__ptr; + + return (((ptr & ~PAGE_MASK) / sizeof(pgd_t)) < PGD_KERNEL_START); +} + +#ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION +/* + * All top-level MITIGATION_PAGE_TABLE_ISOLATION page tables are order-1 pages + * (8k-aligned and 8k in size). The kernel one is at the beginning 4k and + * the user one is in the last 4k. To switch between them, you + * just need to flip the 12th bit in their addresses. + */ +#define PTI_PGTABLE_SWITCH_BIT PAGE_SHIFT + +/* + * This generates better code than the inline assembly in + * __set_bit(). + */ +static inline void *ptr_set_bit(void *ptr, int bit) +{ + unsigned long __ptr = (unsigned long)ptr; + + __ptr |= BIT(bit); + return (void *)__ptr; +} +static inline void *ptr_clear_bit(void *ptr, int bit) +{ + unsigned long __ptr = (unsigned long)ptr; + + __ptr &= ~BIT(bit); + return (void *)__ptr; +} + +static inline pgd_t *kernel_to_user_pgdp(pgd_t *pgdp) +{ + return ptr_set_bit(pgdp, PTI_PGTABLE_SWITCH_BIT); +} + +static inline pgd_t *user_to_kernel_pgdp(pgd_t *pgdp) +{ + return ptr_clear_bit(pgdp, PTI_PGTABLE_SWITCH_BIT); +} + +static inline p4d_t *kernel_to_user_p4dp(p4d_t *p4dp) +{ + return ptr_set_bit(p4dp, PTI_PGTABLE_SWITCH_BIT); +} + +static inline p4d_t *user_to_kernel_p4dp(p4d_t *p4dp) +{ + return ptr_clear_bit(p4dp, PTI_PGTABLE_SWITCH_BIT); +} +#endif /* CONFIG_MITIGATION_PAGE_TABLE_ISOLATION */ + /* * clone_pgd_range(pgd_t *dst, pgd_t *src, int count); * - * dst - pointer to pgd range anwhere on a pgd page + * dst - pointer to pgd range anywhere on a pgd page * src - "" * count - the number of pgds to copy. * @@ -1109,7 +1464,14 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm, */ static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count) { - memcpy(dst, src, count * sizeof(pgd_t)); + memcpy(dst, src, count * sizeof(pgd_t)); +#ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION + if (!static_cpu_has(X86_FEATURE_PTI)) + return; + /* Clone the user space pgd as well */ + memcpy(kernel_to_user_pgdp(dst), kernel_to_user_pgdp(src), + count * sizeof(pgd_t)); +#endif } #define PTE_SHIFT ilog2(PTRS_PER_PTE) @@ -1134,6 +1496,11 @@ static inline void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) { } +static inline void update_mmu_cache_range(struct vm_fault *vmf, + struct vm_area_struct *vma, unsigned long addr, + pte_t *ptep, unsigned int nr) +{ +} static inline void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd) { @@ -1142,6 +1509,20 @@ static inline void update_mmu_cache_pud(struct vm_area_struct *vma, unsigned long addr, pud_t *pud) { } +static inline pte_t pte_swp_mkexclusive(pte_t pte) +{ + return pte_set_flags(pte, _PAGE_SWP_EXCLUSIVE); +} + +static inline bool pte_swp_exclusive(pte_t pte) +{ + return pte_flags(pte) & _PAGE_SWP_EXCLUSIVE; +} + +static inline pte_t pte_swp_clear_exclusive(pte_t pte) +{ + return pte_clear_flags(pte, _PAGE_SWP_EXCLUSIVE); +} #ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY static inline pte_t pte_swp_mksoft_dirty(pte_t pte) @@ -1158,28 +1539,57 @@ static inline pte_t pte_swp_clear_soft_dirty(pte_t pte) { return pte_clear_flags(pte, _PAGE_SWP_SOFT_DIRTY); } + +#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION +static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd) +{ + return pmd_set_flags(pmd, _PAGE_SWP_SOFT_DIRTY); +} + +static inline int pmd_swp_soft_dirty(pmd_t pmd) +{ + return pmd_flags(pmd) & _PAGE_SWP_SOFT_DIRTY; +} + +static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd) +{ + return pmd_clear_flags(pmd, _PAGE_SWP_SOFT_DIRTY); +} +#endif #endif -#define PKRU_AD_BIT 0x1 -#define PKRU_WD_BIT 0x2 -#define PKRU_BITS_PER_PKEY 2 +#ifdef CONFIG_HAVE_ARCH_USERFAULTFD_WP +static inline pte_t pte_swp_mkuffd_wp(pte_t pte) +{ + return pte_set_flags(pte, _PAGE_SWP_UFFD_WP); +} + +static inline int pte_swp_uffd_wp(pte_t pte) +{ + return pte_flags(pte) & _PAGE_SWP_UFFD_WP; +} -static inline bool __pkru_allows_read(u32 pkru, u16 pkey) +static inline pte_t pte_swp_clear_uffd_wp(pte_t pte) { - int pkru_pkey_bits = pkey * PKRU_BITS_PER_PKEY; - return !(pkru & (PKRU_AD_BIT << pkru_pkey_bits)); + return pte_clear_flags(pte, _PAGE_SWP_UFFD_WP); } -static inline bool __pkru_allows_write(u32 pkru, u16 pkey) +static inline pmd_t pmd_swp_mkuffd_wp(pmd_t pmd) { - int pkru_pkey_bits = pkey * PKRU_BITS_PER_PKEY; - /* - * Access-disable disables writes too so we need to check - * both bits here. - */ - return !(pkru & ((PKRU_AD_BIT|PKRU_WD_BIT) << pkru_pkey_bits)); + return pmd_set_flags(pmd, _PAGE_SWP_UFFD_WP); } +static inline int pmd_swp_uffd_wp(pmd_t pmd) +{ + return pmd_flags(pmd) & _PAGE_SWP_UFFD_WP; +} + +static inline pmd_t pmd_swp_clear_uffd_wp(pmd_t pmd) +{ + return pmd_clear_flags(pmd, _PAGE_SWP_UFFD_WP); +} +#endif /* CONFIG_HAVE_ARCH_USERFAULTFD_WP */ + static inline u16 pte_flags_pkey(unsigned long pte_flags) { #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS @@ -1211,6 +1621,11 @@ static inline bool __pte_access_permitted(unsigned long pteval, bool write) { unsigned long need_pte_bits = _PAGE_PRESENT|_PAGE_USER; + /* + * Write=0,Dirty=1 PTEs are shadow stack, which the kernel + * shouldn't generally allow access to, but since they + * are already Write=0, the below logic covers both cases. + */ if (write) need_pte_bits |= _PAGE_RW; @@ -1238,7 +1653,93 @@ static inline bool pud_access_permitted(pud_t pud, bool write) return __pte_access_permitted(pud_val(pud), write); } -#include <asm-generic/pgtable.h> -#endif /* __ASSEMBLY__ */ +#define __HAVE_ARCH_PFN_MODIFY_ALLOWED 1 +extern bool pfn_modify_allowed(unsigned long pfn, pgprot_t prot); + +static inline bool arch_has_pfn_modify_check(void) +{ + return boot_cpu_has_bug(X86_BUG_L1TF); +} + +#define arch_check_zapped_pte arch_check_zapped_pte +void arch_check_zapped_pte(struct vm_area_struct *vma, pte_t pte); + +#define arch_check_zapped_pmd arch_check_zapped_pmd +void arch_check_zapped_pmd(struct vm_area_struct *vma, pmd_t pmd); + +#define arch_check_zapped_pud arch_check_zapped_pud +void arch_check_zapped_pud(struct vm_area_struct *vma, pud_t pud); + +#ifdef CONFIG_XEN_PV +#define arch_has_hw_nonleaf_pmd_young arch_has_hw_nonleaf_pmd_young +static inline bool arch_has_hw_nonleaf_pmd_young(void) +{ + return !cpu_feature_enabled(X86_FEATURE_XENPV); +} +#endif + +#ifdef CONFIG_PAGE_TABLE_CHECK +static inline bool pte_user_accessible_page(pte_t pte) +{ + return (pte_val(pte) & _PAGE_PRESENT) && (pte_val(pte) & _PAGE_USER); +} + +static inline bool pmd_user_accessible_page(pmd_t pmd) +{ + return pmd_leaf(pmd) && (pmd_val(pmd) & _PAGE_PRESENT) && (pmd_val(pmd) & _PAGE_USER); +} + +static inline bool pud_user_accessible_page(pud_t pud) +{ + return pud_leaf(pud) && (pud_val(pud) & _PAGE_PRESENT) && (pud_val(pud) & _PAGE_USER); +} +#endif + +#ifdef CONFIG_X86_SGX +int arch_memory_failure(unsigned long pfn, int flags); +#define arch_memory_failure arch_memory_failure + +bool arch_is_platform_page(u64 paddr); +#define arch_is_platform_page arch_is_platform_page +#endif + +/* + * Use set_p*_safe(), and elide TLB flushing, when confident that *no* + * TLB flush will be required as a result of the "set". For example, use + * in scenarios where it is known ahead of time that the routine is + * setting non-present entries, or re-setting an existing entry to the + * same value. Otherwise, use the typical "set" helpers and flush the + * TLB. + */ +#define set_pte_safe(ptep, pte) \ +({ \ + WARN_ON_ONCE(pte_present(*ptep) && !pte_same(*ptep, pte)); \ + set_pte(ptep, pte); \ +}) + +#define set_pmd_safe(pmdp, pmd) \ +({ \ + WARN_ON_ONCE(pmd_present(*pmdp) && !pmd_same(*pmdp, pmd)); \ + set_pmd(pmdp, pmd); \ +}) + +#define set_pud_safe(pudp, pud) \ +({ \ + WARN_ON_ONCE(pud_present(*pudp) && !pud_same(*pudp, pud)); \ + set_pud(pudp, pud); \ +}) + +#define set_p4d_safe(p4dp, p4d) \ +({ \ + WARN_ON_ONCE(p4d_present(*p4dp) && !p4d_same(*p4dp, p4d)); \ + set_p4d(p4dp, p4d); \ +}) + +#define set_pgd_safe(pgdp, pgd) \ +({ \ + WARN_ON_ONCE(pgd_present(*pgdp) && !pgd_same(*pgdp, pgd)); \ + set_pgd(pgdp, pgd); \ +}) +#endif /* __ASSEMBLER__ */ #endif /* _ASM_X86_PGTABLE_H */ |