1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_X86_PGTABLE_3LEVEL_H 3 #define _ASM_X86_PGTABLE_3LEVEL_H 4 5 /* 6 * Intel Physical Address Extension (PAE) Mode - three-level page 7 * tables on PPro+ CPUs. 8 * 9 * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com> 10 */ 11 12 #define pte_ERROR(e) \ 13 pr_err("%s:%d: bad pte %p(%08lx%08lx)\n", \ 14 __FILE__, __LINE__, &(e), (e).pte_high, (e).pte_low) 15 #define pmd_ERROR(e) \ 16 pr_err("%s:%d: bad pmd %p(%016Lx)\n", \ 17 __FILE__, __LINE__, &(e), pmd_val(e)) 18 #define pgd_ERROR(e) \ 19 pr_err("%s:%d: bad pgd %p(%016Lx)\n", \ 20 __FILE__, __LINE__, &(e), pgd_val(e)) 21 22 #define pxx_xchg64(_pxx, _ptr, _val) ({ \ 23 _pxx##val_t *_p = (_pxx##val_t *)_ptr; \ 24 _pxx##val_t _o = *_p; \ 25 do { } while (!try_cmpxchg64(_p, &_o, (_val))); \ 26 native_make_##_pxx(_o); \ 27 }) 28 29 /* 30 * Rules for using set_pte: the pte being assigned *must* be 31 * either not present or in a state where the hardware will 32 * not attempt to update the pte. In places where this is 33 * not possible, use pte_get_and_clear to obtain the old pte 34 * value and then use set_pte to update it. -ben 35 */ 36 static inline void native_set_pte(pte_t *ptep, pte_t pte) 37 { 38 WRITE_ONCE(ptep->pte_high, pte.pte_high); 39 smp_wmb(); 40 WRITE_ONCE(ptep->pte_low, pte.pte_low); 41 } 42 43 static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte) 44 { 45 pxx_xchg64(pte, ptep, native_pte_val(pte)); 46 } 47 48 static inline void native_set_pmd(pmd_t *pmdp, pmd_t pmd) 49 { 50 pxx_xchg64(pmd, pmdp, native_pmd_val(pmd)); 51 } 52 53 static inline void native_set_pud(pud_t *pudp, pud_t pud) 54 { 55 #ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION 56 pud.p4d.pgd = pti_set_user_pgtbl(&pudp->p4d.pgd, pud.p4d.pgd); 57 #endif 58 pxx_xchg64(pud, pudp, native_pud_val(pud)); 59 } 60 61 /* 62 * For PTEs and PDEs, we must clear the P-bit first when clearing a page table 63 * entry, so clear the bottom half first and enforce ordering with a compiler 64 * barrier. 65 */ 66 static inline void native_pte_clear(struct mm_struct *mm, unsigned long addr, 67 pte_t *ptep) 68 { 69 WRITE_ONCE(ptep->pte_low, 0); 70 smp_wmb(); 71 WRITE_ONCE(ptep->pte_high, 0); 72 } 73 74 static inline void native_pmd_clear(pmd_t *pmdp) 75 { 76 WRITE_ONCE(pmdp->pmd_low, 0); 77 smp_wmb(); 78 WRITE_ONCE(pmdp->pmd_high, 0); 79 } 80 81 static inline void native_pud_clear(pud_t *pudp) 82 { 83 } 84 85 static inline void pud_clear(pud_t *pudp) 86 { 87 set_pud(pudp, __pud(0)); 88 89 /* 90 * According to Intel App note "TLBs, Paging-Structure Caches, 91 * and Their Invalidation", April 2007, document 317080-001, 92 * section 8.1: in PAE mode we explicitly have to flush the 93 * TLB via cr3 if the top-level pgd is changed... 94 * 95 * Currently all places where pud_clear() is called either have 96 * flush_tlb_mm() followed or don't need TLB flush (x86_64 code or 97 * pud_clear_bad()), so we don't need TLB flush here. 98 */ 99 } 100 101 102 #ifdef CONFIG_SMP 103 static inline pte_t native_ptep_get_and_clear(pte_t *ptep) 104 { 105 return pxx_xchg64(pte, ptep, 0ULL); 106 } 107 108 static inline pmd_t native_pmdp_get_and_clear(pmd_t *pmdp) 109 { 110 return pxx_xchg64(pmd, pmdp, 0ULL); 111 } 112 113 static inline pud_t native_pudp_get_and_clear(pud_t *pudp) 114 { 115 return pxx_xchg64(pud, pudp, 0ULL); 116 } 117 #else 118 #define native_ptep_get_and_clear(xp) native_local_ptep_get_and_clear(xp) 119 #define native_pmdp_get_and_clear(xp) native_local_pmdp_get_and_clear(xp) 120 #define native_pudp_get_and_clear(xp) native_local_pudp_get_and_clear(xp) 121 #endif 122 123 #ifndef pmdp_establish 124 #define pmdp_establish pmdp_establish 125 static inline pmd_t pmdp_establish(struct vm_area_struct *vma, 126 unsigned long address, pmd_t *pmdp, pmd_t pmd) 127 { 128 pmd_t old; 129 130 /* 131 * If pmd has present bit cleared we can get away without expensive 132 * cmpxchg64: we can update pmdp half-by-half without racing with 133 * anybody. 134 */ 135 if (!(pmd_val(pmd) & _PAGE_PRESENT)) { 136 /* xchg acts as a barrier before setting of the high bits */ 137 old.pmd_low = xchg(&pmdp->pmd_low, pmd.pmd_low); 138 old.pmd_high = READ_ONCE(pmdp->pmd_high); 139 WRITE_ONCE(pmdp->pmd_high, pmd.pmd_high); 140 141 return old; 142 } 143 144 return pxx_xchg64(pmd, pmdp, pmd.pmd); 145 } 146 #endif 147 148 /* 149 * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that 150 * are !pte_none() && !pte_present(). 151 * 152 * Format of swap PTEs: 153 * 154 * 6 6 6 6 5 5 5 5 5 5 5 5 5 5 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3 155 * 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 156 * < type -> <---------------------- offset ---------------------- 157 * 158 * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 159 * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 160 * --------------------------------------------> 0 E 0 0 0 0 0 0 0 161 * 162 * E is the exclusive marker that is not stored in swap entries. 163 */ 164 #define SWP_TYPE_BITS 5 165 #define _SWP_TYPE_MASK ((1U << SWP_TYPE_BITS) - 1) 166 167 #define SWP_OFFSET_FIRST_BIT (_PAGE_BIT_PROTNONE + 1) 168 169 /* We always extract/encode the offset by shifting it all the way up, and then down again */ 170 #define SWP_OFFSET_SHIFT (SWP_OFFSET_FIRST_BIT + SWP_TYPE_BITS) 171 172 #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > SWP_TYPE_BITS) 173 #define __swp_type(x) (((x).val) & _SWP_TYPE_MASK) 174 #define __swp_offset(x) ((x).val >> SWP_TYPE_BITS) 175 #define __swp_entry(type, offset) ((swp_entry_t){((type) & _SWP_TYPE_MASK) \ 176 | (offset) << SWP_TYPE_BITS}) 177 178 /* 179 * Normally, __swp_entry() converts from arch-independent swp_entry_t to 180 * arch-dependent swp_entry_t, and __swp_entry_to_pte() just stores the result 181 * to pte. But here we have 32bit swp_entry_t and 64bit pte, and need to use the 182 * whole 64 bits. Thus, we shift the "real" arch-dependent conversion to 183 * __swp_entry_to_pte() through the following helper macro based on 64bit 184 * __swp_entry(). 185 */ 186 #define __swp_pteval_entry(type, offset) ((pteval_t) { \ 187 (~(pteval_t)(offset) << SWP_OFFSET_SHIFT >> SWP_TYPE_BITS) \ 188 | ((pteval_t)(type) << (64 - SWP_TYPE_BITS)) }) 189 190 #define __swp_entry_to_pte(x) ((pte_t){ .pte = \ 191 __swp_pteval_entry(__swp_type(x), __swp_offset(x)) }) 192 /* 193 * Analogically, __pte_to_swp_entry() doesn't just extract the arch-dependent 194 * swp_entry_t, but also has to convert it from 64bit to the 32bit 195 * intermediate representation, using the following macros based on 64bit 196 * __swp_type() and __swp_offset(). 197 */ 198 #define __pteval_swp_type(x) ((unsigned long)((x).pte >> (64 - SWP_TYPE_BITS))) 199 #define __pteval_swp_offset(x) ((unsigned long)(~((x).pte) << SWP_TYPE_BITS >> SWP_OFFSET_SHIFT)) 200 201 #define __pte_to_swp_entry(pte) (__swp_entry(__pteval_swp_type(pte), \ 202 __pteval_swp_offset(pte))) 203 204 /* We borrow bit 7 to store the exclusive marker in swap PTEs. */ 205 #define _PAGE_SWP_EXCLUSIVE _PAGE_PSE 206 207 #include <asm/pgtable-invert.h> 208 209 #endif /* _ASM_X86_PGTABLE_3LEVEL_H */ 210