1 /* 2 * s390x MMU 3 * 4 * Copyright (c) 2017 Red Hat Inc 5 * 6 * Authors: 7 * David Hildenbrand <david@redhat.com> 8 * 9 * This code is free software; you can redistribute it and/or modify it 10 * under the terms of the GNU Library General Public License version 2. 11 */ 12 13 #include <libcflat.h> 14 #include <asm/pgtable.h> 15 #include <asm/arch_def.h> 16 #include <asm/barrier.h> 17 #include <vmalloc.h> 18 19 static pgd_t *table_root; 20 21 void configure_dat(int enable) 22 { 23 uint64_t mask; 24 25 if (enable) 26 mask = extract_psw_mask() | PSW_MASK_DAT; 27 else 28 mask = extract_psw_mask() & ~PSW_MASK_DAT; 29 30 load_psw_mask(mask); 31 } 32 33 static void mmu_enable(pgd_t *pgtable) 34 { 35 struct lowcore *lc = NULL; 36 const uint64_t asce = __pa(pgtable) | ASCE_DT_REGION1 | 37 REGION_TABLE_LENGTH; 38 39 /* set primary asce */ 40 lctlg(1, asce); 41 assert(stctg(1) == asce); 42 43 /* enable dat (primary == 0 set as default) */ 44 configure_dat(1); 45 46 /* we can now also use DAT unconditionally in our PGM handler */ 47 lc->pgm_new_psw.mask |= PSW_MASK_DAT; 48 } 49 50 static pteval_t *get_pte(pgd_t *pgtable, uintptr_t vaddr) 51 { 52 pgd_t *pgd = pgd_offset(pgtable, vaddr); 53 p4d_t *p4d = p4d_alloc(pgd, vaddr); 54 pud_t *pud = pud_alloc(p4d, vaddr); 55 pmd_t *pmd = pmd_alloc(pud, vaddr); 56 pte_t *pte = pte_alloc(pmd, vaddr); 57 58 return &pte_val(*pte); 59 } 60 61 phys_addr_t virt_to_pte_phys(pgd_t *pgtable, void *vaddr) 62 { 63 return (*get_pte(pgtable, (uintptr_t)vaddr) & PAGE_MASK) + 64 ((unsigned long)vaddr & ~PAGE_MASK); 65 } 66 67 static pteval_t *set_pte(pgd_t *pgtable, pteval_t val, void *vaddr) 68 { 69 pteval_t *p_pte = get_pte(pgtable, (uintptr_t)vaddr); 70 71 /* first flush the old entry (if we're replacing anything) */ 72 if (!(*p_pte & PAGE_ENTRY_I)) 73 ipte((uintptr_t)vaddr, p_pte); 74 75 *p_pte = val; 76 return p_pte; 77 } 78 79 pteval_t *install_page(pgd_t *pgtable, phys_addr_t phys, void *vaddr) 80 { 81 return set_pte(pgtable, __pa(phys), vaddr); 82 } 83 84 void protect_page(void *vaddr, unsigned long prot) 85 { 86 pteval_t *p_pte = get_pte(table_root, (uintptr_t)vaddr); 87 pteval_t n_pte = *p_pte | prot; 88 89 set_pte(table_root, n_pte, vaddr); 90 } 91 92 void unprotect_page(void *vaddr, unsigned long prot) 93 { 94 pteval_t *p_pte = get_pte(table_root, (uintptr_t)vaddr); 95 pteval_t n_pte = *p_pte & ~prot; 96 97 set_pte(table_root, n_pte, vaddr); 98 } 99 100 void protect_range(void *start, unsigned long len, unsigned long prot) 101 { 102 uintptr_t curr = (uintptr_t)start & PAGE_MASK; 103 104 len &= PAGE_MASK; 105 for (; len; len -= PAGE_SIZE, curr += PAGE_SIZE) 106 protect_page((void *)curr, prot); 107 } 108 109 void unprotect_range(void *start, unsigned long len, unsigned long prot) 110 { 111 uintptr_t curr = (uintptr_t)start & PAGE_MASK; 112 113 len &= PAGE_MASK; 114 for (; len; len -= PAGE_SIZE, curr += PAGE_SIZE) 115 unprotect_page((void *)curr, prot); 116 } 117 118 static void setup_identity(pgd_t *pgtable, phys_addr_t start_addr, 119 phys_addr_t end_addr) 120 { 121 phys_addr_t cur; 122 123 start_addr &= PAGE_MASK; 124 for (cur = start_addr; true; cur += PAGE_SIZE) { 125 if (start_addr < end_addr && cur >= end_addr) 126 break; 127 if (start_addr > end_addr && cur <= end_addr) 128 break; 129 install_page(pgtable, cur, __va(cur)); 130 } 131 } 132 133 void *setup_mmu(phys_addr_t phys_end){ 134 pgd_t *page_root; 135 136 /* allocate a region-1 table */ 137 page_root = pgd_alloc_one(); 138 139 /* map all physical memory 1:1 */ 140 setup_identity(page_root, 0, phys_end); 141 142 /* generate 128MB of invalid adresses at the end (for testing PGM) */ 143 init_alloc_vpage((void *) -(1UL << 27)); 144 setup_identity(page_root, -(1UL << 27), 0); 145 146 /* finally enable DAT with the new table */ 147 mmu_enable(page_root); 148 table_root = page_root; 149 return page_root; 150 } 151