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
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