1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_POWERPC_BOOK3S_64_HASH_64K_H 3 #define _ASM_POWERPC_BOOK3S_64_HASH_64K_H 4 5 #define H_PTE_INDEX_SIZE 8 // size: 8B << 8 = 2KB, maps 2^8 x 64KB = 16MB 6 #define H_PMD_INDEX_SIZE 10 // size: 8B << 10 = 8KB, maps 2^10 x 16MB = 16GB 7 #define H_PUD_INDEX_SIZE 10 // size: 8B << 10 = 8KB, maps 2^10 x 16GB = 16TB 8 #define H_PGD_INDEX_SIZE 8 // size: 8B << 8 = 2KB, maps 2^8 x 16TB = 4PB 9 10 /* 11 * If we store section details in page->flags we can't increase the MAX_PHYSMEM_BITS 12 * if we increase SECTIONS_WIDTH we will not store node details in page->flags and 13 * page_to_nid does a page->section->node lookup 14 * Hence only increase for VMEMMAP. Further depending on SPARSEMEM_EXTREME reduce 15 * memory requirements with large number of sections. 16 * 51 bits is the max physical real address on POWER9 17 */ 18 #if defined(CONFIG_SPARSEMEM_VMEMMAP) && defined(CONFIG_SPARSEMEM_EXTREME) 19 #define H_MAX_PHYSMEM_BITS 51 20 #else 21 #define H_MAX_PHYSMEM_BITS 46 22 #endif 23 24 /* 25 * Each context is 512TB size. SLB miss for first context/default context 26 * is handled in the hotpath. 27 */ 28 #define MAX_EA_BITS_PER_CONTEXT 49 29 #define REGION_SHIFT MAX_EA_BITS_PER_CONTEXT 30 31 /* 32 * We use one context for each MAP area. 33 */ 34 #define H_KERN_MAP_SIZE (1UL << MAX_EA_BITS_PER_CONTEXT) 35 36 /* 37 * Define the address range of the kernel non-linear virtual area 38 * 2PB 39 */ 40 #define H_KERN_VIRT_START ASM_CONST(0xc008000000000000) 41 42 /* 43 * 64k aligned address free up few of the lower bits of RPN for us 44 * We steal that here. For more deatils look at pte_pfn/pfn_pte() 45 */ 46 #define H_PAGE_COMBO _RPAGE_RPN0 /* this is a combo 4k page */ 47 #define H_PAGE_4K_PFN _RPAGE_RPN1 /* PFN is for a single 4k page */ 48 #define H_PAGE_BUSY _RPAGE_RSV1 /* software: PTE & hash are busy */ 49 #define H_PAGE_HASHPTE _RPAGE_RPN43 /* PTE has associated HPTE */ 50 51 /* memory key bits. */ 52 #define H_PTE_PKEY_BIT4 _RPAGE_PKEY_BIT4 53 #define H_PTE_PKEY_BIT3 _RPAGE_PKEY_BIT3 54 #define H_PTE_PKEY_BIT2 _RPAGE_PKEY_BIT2 55 #define H_PTE_PKEY_BIT1 _RPAGE_PKEY_BIT1 56 #define H_PTE_PKEY_BIT0 _RPAGE_PKEY_BIT0 57 58 /* 59 * We need to differentiate between explicit huge page and THP huge 60 * page, since THP huge page also need to track real subpage details 61 */ 62 #define H_PAGE_THP_HUGE H_PAGE_4K_PFN 63 64 /* PTE flags to conserve for HPTE identification */ 65 #define _PAGE_HPTEFLAGS (H_PAGE_BUSY | H_PAGE_HASHPTE | H_PAGE_COMBO) 66 /* 67 * We use a 2K PTE page fragment and another 2K for storing 68 * real_pte_t hash index 69 * 8 bytes per each pte entry and another 8 bytes for storing 70 * slot details. 71 */ 72 #define H_PTE_FRAG_SIZE_SHIFT (H_PTE_INDEX_SIZE + 3 + 1) 73 #define H_PTE_FRAG_NR (PAGE_SIZE >> H_PTE_FRAG_SIZE_SHIFT) 74 75 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLB_PAGE) 76 #define H_PMD_FRAG_SIZE_SHIFT (H_PMD_INDEX_SIZE + 3 + 1) 77 #else 78 #define H_PMD_FRAG_SIZE_SHIFT (H_PMD_INDEX_SIZE + 3) 79 #endif 80 #define H_PMD_FRAG_NR (PAGE_SIZE >> H_PMD_FRAG_SIZE_SHIFT) 81 82 #ifndef __ASSEMBLY__ 83 #include <asm/errno.h> 84 85 /* 86 * With 64K pages on hash table, we have a special PTE format that 87 * uses a second "half" of the page table to encode sub-page information 88 * in order to deal with 64K made of 4K HW pages. Thus we override the 89 * generic accessors and iterators here 90 */ 91 #define __real_pte __real_pte 92 static inline real_pte_t __real_pte(pte_t pte, pte_t *ptep, int offset) 93 { 94 real_pte_t rpte; 95 unsigned long *hidxp; 96 97 rpte.pte = pte; 98 99 /* 100 * Ensure that we do not read the hidx before we read the PTE. Because 101 * the writer side is expected to finish writing the hidx first followed 102 * by the PTE, by using smp_wmb(). pte_set_hash_slot() ensures that. 103 */ 104 smp_rmb(); 105 106 hidxp = (unsigned long *)(ptep + offset); 107 rpte.hidx = *hidxp; 108 return rpte; 109 } 110 111 /* 112 * shift the hidx representation by one-modulo-0xf; i.e hidx 0 is respresented 113 * as 1, 1 as 2,... , and 0xf as 0. This convention lets us represent a 114 * invalid hidx 0xf with a 0x0 bit value. PTEs are anyway zero'd when 115 * allocated. We dont have to zero them gain; thus save on the initialization. 116 */ 117 #define HIDX_UNSHIFT_BY_ONE(x) ((x + 0xfUL) & 0xfUL) /* shift backward by one */ 118 #define HIDX_SHIFT_BY_ONE(x) ((x + 0x1UL) & 0xfUL) /* shift forward by one */ 119 #define HIDX_BITS(x, index) (x << (index << 2)) 120 #define BITS_TO_HIDX(x, index) ((x >> (index << 2)) & 0xfUL) 121 #define INVALID_RPTE_HIDX 0x0UL 122 123 static inline unsigned long __rpte_to_hidx(real_pte_t rpte, unsigned long index) 124 { 125 return HIDX_UNSHIFT_BY_ONE(BITS_TO_HIDX(rpte.hidx, index)); 126 } 127 128 /* 129 * Commit the hidx and return PTE bits that needs to be modified. The caller is 130 * expected to modify the PTE bits accordingly and commit the PTE to memory. 131 */ 132 static inline unsigned long pte_set_hidx(pte_t *ptep, real_pte_t rpte, 133 unsigned int subpg_index, 134 unsigned long hidx, int offset) 135 { 136 unsigned long *hidxp = (unsigned long *)(ptep + offset); 137 138 rpte.hidx &= ~HIDX_BITS(0xfUL, subpg_index); 139 *hidxp = rpte.hidx | HIDX_BITS(HIDX_SHIFT_BY_ONE(hidx), subpg_index); 140 141 /* 142 * Anyone reading PTE must ensure hidx bits are read after reading the 143 * PTE by using the read-side barrier smp_rmb(). __real_pte() can be 144 * used for that. 145 */ 146 smp_wmb(); 147 148 /* No PTE bits to be modified, return 0x0UL */ 149 return 0x0UL; 150 } 151 152 #define __rpte_to_pte(r) ((r).pte) 153 extern bool __rpte_sub_valid(real_pte_t rpte, unsigned long index); 154 /* 155 * Trick: we set __end to va + 64k, which happens works for 156 * a 16M page as well as we want only one iteration 157 */ 158 #define pte_iterate_hashed_subpages(rpte, psize, vpn, index, shift) \ 159 do { \ 160 unsigned long __end = vpn + (1UL << (PAGE_SHIFT - VPN_SHIFT)); \ 161 unsigned __split = (psize == MMU_PAGE_4K || \ 162 psize == MMU_PAGE_64K_AP); \ 163 shift = mmu_psize_defs[psize].shift; \ 164 for (index = 0; vpn < __end; index++, \ 165 vpn += (1L << (shift - VPN_SHIFT))) { \ 166 if (!__split || __rpte_sub_valid(rpte, index)) 167 168 #define pte_iterate_hashed_end() } } while(0) 169 170 #define pte_pagesize_index(mm, addr, pte) \ 171 (((pte) & H_PAGE_COMBO)? MMU_PAGE_4K: MMU_PAGE_64K) 172 173 extern int remap_pfn_range(struct vm_area_struct *, unsigned long addr, 174 unsigned long pfn, unsigned long size, pgprot_t); 175 static inline int hash__remap_4k_pfn(struct vm_area_struct *vma, unsigned long addr, 176 unsigned long pfn, pgprot_t prot) 177 { 178 if (pfn > (PTE_RPN_MASK >> PAGE_SHIFT)) { 179 WARN(1, "remap_4k_pfn called with wrong pfn value\n"); 180 return -EINVAL; 181 } 182 return remap_pfn_range(vma, addr, pfn, PAGE_SIZE, 183 __pgprot(pgprot_val(prot) | H_PAGE_4K_PFN)); 184 } 185 186 #define H_PTE_TABLE_SIZE PTE_FRAG_SIZE 187 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined (CONFIG_HUGETLB_PAGE) 188 #define H_PMD_TABLE_SIZE ((sizeof(pmd_t) << PMD_INDEX_SIZE) + \ 189 (sizeof(unsigned long) << PMD_INDEX_SIZE)) 190 #else 191 #define H_PMD_TABLE_SIZE (sizeof(pmd_t) << PMD_INDEX_SIZE) 192 #endif 193 #ifdef CONFIG_HUGETLB_PAGE 194 #define H_PUD_TABLE_SIZE ((sizeof(pud_t) << PUD_INDEX_SIZE) + \ 195 (sizeof(unsigned long) << PUD_INDEX_SIZE)) 196 #else 197 #define H_PUD_TABLE_SIZE (sizeof(pud_t) << PUD_INDEX_SIZE) 198 #endif 199 #define H_PGD_TABLE_SIZE (sizeof(pgd_t) << PGD_INDEX_SIZE) 200 201 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 202 static inline char *get_hpte_slot_array(pmd_t *pmdp) 203 { 204 /* 205 * The hpte hindex is stored in the pgtable whose address is in the 206 * second half of the PMD 207 * 208 * Order this load with the test for pmd_trans_huge in the caller 209 */ 210 smp_rmb(); 211 return *(char **)(pmdp + PTRS_PER_PMD); 212 213 214 } 215 /* 216 * The linux hugepage PMD now include the pmd entries followed by the address 217 * to the stashed pgtable_t. The stashed pgtable_t contains the hpte bits. 218 * [ 000 | 1 bit secondary | 3 bit hidx | 1 bit valid]. We use one byte per 219 * each HPTE entry. With 16MB hugepage and 64K HPTE we need 256 entries and 220 * with 4K HPTE we need 4096 entries. Both will fit in a 4K pgtable_t. 221 * 222 * The top three bits are intentionally left as zero. This memory location 223 * are also used as normal page PTE pointers. So if we have any pointers 224 * left around while we collapse a hugepage, we need to make sure 225 * _PAGE_PRESENT bit of that is zero when we look at them 226 */ 227 static inline unsigned int hpte_valid(unsigned char *hpte_slot_array, int index) 228 { 229 return hpte_slot_array[index] & 0x1; 230 } 231 232 static inline unsigned int hpte_hash_index(unsigned char *hpte_slot_array, 233 int index) 234 { 235 return hpte_slot_array[index] >> 1; 236 } 237 238 static inline void mark_hpte_slot_valid(unsigned char *hpte_slot_array, 239 unsigned int index, unsigned int hidx) 240 { 241 hpte_slot_array[index] = (hidx << 1) | 0x1; 242 } 243 244 /* 245 * 246 * For core kernel code by design pmd_trans_huge is never run on any hugetlbfs 247 * page. The hugetlbfs page table walking and mangling paths are totally 248 * separated form the core VM paths and they're differentiated by 249 * VM_HUGETLB being set on vm_flags well before any pmd_trans_huge could run. 250 * 251 * pmd_trans_huge() is defined as false at build time if 252 * CONFIG_TRANSPARENT_HUGEPAGE=n to optimize away code blocks at build 253 * time in such case. 254 * 255 * For ppc64 we need to differntiate from explicit hugepages from THP, because 256 * for THP we also track the subpage details at the pmd level. We don't do 257 * that for explicit huge pages. 258 * 259 */ 260 static inline int hash__pmd_trans_huge(pmd_t pmd) 261 { 262 return !!((pmd_val(pmd) & (_PAGE_PTE | H_PAGE_THP_HUGE | _PAGE_DEVMAP)) == 263 (_PAGE_PTE | H_PAGE_THP_HUGE)); 264 } 265 266 static inline pmd_t hash__pmd_mkhuge(pmd_t pmd) 267 { 268 return __pmd(pmd_val(pmd) | (_PAGE_PTE | H_PAGE_THP_HUGE)); 269 } 270 271 extern unsigned long hash__pmd_hugepage_update(struct mm_struct *mm, 272 unsigned long addr, pmd_t *pmdp, 273 unsigned long clr, unsigned long set); 274 extern pmd_t hash__pmdp_collapse_flush(struct vm_area_struct *vma, 275 unsigned long address, pmd_t *pmdp); 276 extern void hash__pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, 277 pgtable_t pgtable); 278 extern pgtable_t hash__pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp); 279 extern pmd_t hash__pmdp_huge_get_and_clear(struct mm_struct *mm, 280 unsigned long addr, pmd_t *pmdp); 281 extern int hash__has_transparent_hugepage(void); 282 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 283 284 static inline pmd_t hash__pmd_mkdevmap(pmd_t pmd) 285 { 286 return __pmd(pmd_val(pmd) | (_PAGE_PTE | H_PAGE_THP_HUGE | _PAGE_DEVMAP)); 287 } 288 289 #endif /* __ASSEMBLY__ */ 290 291 #endif /* _ASM_POWERPC_BOOK3S_64_HASH_64K_H */ 292