1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright IBM Corp. 2006
4 * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
7 #include <linux/memory_hotplug.h>
8 #include <linux/memblock.h>
11 #include <linux/init.h>
12 #include <linux/list.h>
13 #include <linux/hugetlb.h>
14 #include <linux/slab.h>
15 #include <asm/cacheflush.h>
16 #include <asm/pgalloc.h>
17 #include <asm/setup.h>
18 #include <asm/tlbflush.h>
19 #include <asm/sections.h>
20 #include <asm/set_memory.h>
22 static DEFINE_MUTEX(vmem_mutex);
24 static void __ref *vmem_alloc_pages(unsigned int order)
26 unsigned long size = PAGE_SIZE << order;
28 if (slab_is_available())
29 return (void *)__get_free_pages(GFP_KERNEL, order);
30 return memblock_alloc(size, size);
33 static void vmem_free_pages(unsigned long addr, int order)
35 /* We don't expect boot memory to be removed ever. */
36 if (!slab_is_available() ||
37 WARN_ON_ONCE(PageReserved(virt_to_page(addr))))
39 free_pages(addr, order);
42 void *vmem_crst_alloc(unsigned long val)
46 table = vmem_alloc_pages(CRST_ALLOC_ORDER);
48 crst_table_init(table, val);
52 pte_t __ref *vmem_pte_alloc(void)
54 unsigned long size = PTRS_PER_PTE * sizeof(pte_t);
57 if (slab_is_available())
58 pte = (pte_t *) page_table_alloc(&init_mm);
60 pte = (pte_t *) memblock_alloc(size, size);
63 memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE);
67 static void vmem_pte_free(unsigned long *table)
69 /* We don't expect boot memory to be removed ever. */
70 if (!slab_is_available() ||
71 WARN_ON_ONCE(PageReserved(virt_to_page(table))))
73 page_table_free(&init_mm, table);
76 #define PAGE_UNUSED 0xFD
79 * The unused vmemmap range, which was not yet memset(PAGE_UNUSED) ranges
80 * from unused_sub_pmd_start to next PMD_SIZE boundary.
82 static unsigned long unused_sub_pmd_start;
84 static void vmemmap_flush_unused_sub_pmd(void)
86 if (!unused_sub_pmd_start)
88 memset((void *)unused_sub_pmd_start, PAGE_UNUSED,
89 ALIGN(unused_sub_pmd_start, PMD_SIZE) - unused_sub_pmd_start);
90 unused_sub_pmd_start = 0;
93 static void vmemmap_mark_sub_pmd_used(unsigned long start, unsigned long end)
96 * As we expect to add in the same granularity as we remove, it's
97 * sufficient to mark only some piece used to block the memmap page from
98 * getting removed (just in case the memmap never gets initialized,
99 * e.g., because the memory block never gets onlined).
101 memset((void *)start, 0, sizeof(struct page));
104 static void vmemmap_use_sub_pmd(unsigned long start, unsigned long end)
107 * We only optimize if the new used range directly follows the
108 * previously unused range (esp., when populating consecutive sections).
110 if (unused_sub_pmd_start == start) {
111 unused_sub_pmd_start = end;
112 if (likely(IS_ALIGNED(unused_sub_pmd_start, PMD_SIZE)))
113 unused_sub_pmd_start = 0;
116 vmemmap_flush_unused_sub_pmd();
117 vmemmap_mark_sub_pmd_used(start, end);
120 static void vmemmap_use_new_sub_pmd(unsigned long start, unsigned long end)
122 unsigned long page = ALIGN_DOWN(start, PMD_SIZE);
124 vmemmap_flush_unused_sub_pmd();
126 /* Could be our memmap page is filled with PAGE_UNUSED already ... */
127 vmemmap_mark_sub_pmd_used(start, end);
129 /* Mark the unused parts of the new memmap page PAGE_UNUSED. */
130 if (!IS_ALIGNED(start, PMD_SIZE))
131 memset((void *)page, PAGE_UNUSED, start - page);
133 * We want to avoid memset(PAGE_UNUSED) when populating the vmemmap of
134 * consecutive sections. Remember for the last added PMD the last
135 * unused range in the populated PMD.
137 if (!IS_ALIGNED(end, PMD_SIZE))
138 unused_sub_pmd_start = end;
141 /* Returns true if the PMD is completely unused and can be freed. */
142 static bool vmemmap_unuse_sub_pmd(unsigned long start, unsigned long end)
144 unsigned long page = ALIGN_DOWN(start, PMD_SIZE);
146 vmemmap_flush_unused_sub_pmd();
147 memset((void *)start, PAGE_UNUSED, end - start);
148 return !memchr_inv((void *)page, PAGE_UNUSED, PMD_SIZE);
151 /* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */
152 static int __ref modify_pte_table(pmd_t *pmd, unsigned long addr,
153 unsigned long end, bool add, bool direct)
155 unsigned long prot, pages = 0;
159 prot = pgprot_val(PAGE_KERNEL);
161 prot &= ~_PAGE_NOEXEC;
163 pte = pte_offset_kernel(pmd, addr);
164 for (; addr < end; addr += PAGE_SIZE, pte++) {
169 vmem_free_pages((unsigned long) pfn_to_virt(pte_pfn(*pte)), 0);
170 pte_clear(&init_mm, addr, pte);
171 } else if (pte_none(*pte)) {
173 void *new_page = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
177 pte_val(*pte) = __pa(new_page) | prot;
179 pte_val(*pte) = __pa(addr) | prot;
189 update_page_count(PG_DIRECT_MAP_4K, add ? pages : -pages);
193 static void try_free_pte_table(pmd_t *pmd, unsigned long start)
198 /* We can safely assume this is fully in 1:1 mapping & vmemmap area */
199 pte = pte_offset_kernel(pmd, start);
200 for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
204 vmem_pte_free((unsigned long *) pmd_deref(*pmd));
208 /* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */
209 static int __ref modify_pmd_table(pud_t *pud, unsigned long addr,
210 unsigned long end, bool add, bool direct)
212 unsigned long next, prot, pages = 0;
217 prot = pgprot_val(SEGMENT_KERNEL);
219 prot &= ~_SEGMENT_ENTRY_NOEXEC;
221 pmd = pmd_offset(pud, addr);
222 for (; addr < end; addr = next, pmd++) {
223 next = pmd_addr_end(addr, end);
227 if (pmd_large(*pmd)) {
228 if (IS_ALIGNED(addr, PMD_SIZE) &&
229 IS_ALIGNED(next, PMD_SIZE)) {
231 vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE));
234 } else if (!direct && vmemmap_unuse_sub_pmd(addr, next)) {
235 vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE));
240 } else if (pmd_none(*pmd)) {
241 if (IS_ALIGNED(addr, PMD_SIZE) &&
242 IS_ALIGNED(next, PMD_SIZE) &&
243 MACHINE_HAS_EDAT1 && addr && direct &&
244 !debug_pagealloc_enabled()) {
245 pmd_val(*pmd) = __pa(addr) | prot;
248 } else if (!direct && MACHINE_HAS_EDAT1) {
252 * Use 1MB frames for vmemmap if available. We
253 * always use large frames even if they are only
254 * partially used. Otherwise we would have also
255 * page tables since vmemmap_populate gets
256 * called for each section separately.
258 new_page = vmemmap_alloc_block(PMD_SIZE, NUMA_NO_NODE);
260 pmd_val(*pmd) = __pa(new_page) | prot;
261 if (!IS_ALIGNED(addr, PMD_SIZE) ||
262 !IS_ALIGNED(next, PMD_SIZE)) {
263 vmemmap_use_new_sub_pmd(addr, next);
268 pte = vmem_pte_alloc();
271 pmd_populate(&init_mm, pmd, pte);
272 } else if (pmd_large(*pmd)) {
274 vmemmap_use_sub_pmd(addr, next);
277 ret = modify_pte_table(pmd, addr, next, add, direct);
281 try_free_pte_table(pmd, addr & PMD_MASK);
286 update_page_count(PG_DIRECT_MAP_1M, add ? pages : -pages);
290 static void try_free_pmd_table(pud_t *pud, unsigned long start)
292 const unsigned long end = start + PUD_SIZE;
296 /* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
297 if (end > VMALLOC_START)
300 if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end)
303 pmd = pmd_offset(pud, start);
304 for (i = 0; i < PTRS_PER_PMD; i++, pmd++)
307 vmem_free_pages(pud_deref(*pud), CRST_ALLOC_ORDER);
311 static int modify_pud_table(p4d_t *p4d, unsigned long addr, unsigned long end,
312 bool add, bool direct)
314 unsigned long next, prot, pages = 0;
319 prot = pgprot_val(REGION3_KERNEL);
321 prot &= ~_REGION_ENTRY_NOEXEC;
322 pud = pud_offset(p4d, addr);
323 for (; addr < end; addr = next, pud++) {
324 next = pud_addr_end(addr, end);
328 if (pud_large(*pud)) {
329 if (IS_ALIGNED(addr, PUD_SIZE) &&
330 IS_ALIGNED(next, PUD_SIZE)) {
336 } else if (pud_none(*pud)) {
337 if (IS_ALIGNED(addr, PUD_SIZE) &&
338 IS_ALIGNED(next, PUD_SIZE) &&
339 MACHINE_HAS_EDAT2 && addr && direct &&
340 !debug_pagealloc_enabled()) {
341 pud_val(*pud) = __pa(addr) | prot;
345 pmd = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
348 pud_populate(&init_mm, pud, pmd);
349 } else if (pud_large(*pud)) {
352 ret = modify_pmd_table(pud, addr, next, add, direct);
356 try_free_pmd_table(pud, addr & PUD_MASK);
361 update_page_count(PG_DIRECT_MAP_2G, add ? pages : -pages);
365 static void try_free_pud_table(p4d_t *p4d, unsigned long start)
367 const unsigned long end = start + P4D_SIZE;
371 /* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
372 if (end > VMALLOC_START)
375 if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end)
379 pud = pud_offset(p4d, start);
380 for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
384 vmem_free_pages(p4d_deref(*p4d), CRST_ALLOC_ORDER);
388 static int modify_p4d_table(pgd_t *pgd, unsigned long addr, unsigned long end,
389 bool add, bool direct)
396 p4d = p4d_offset(pgd, addr);
397 for (; addr < end; addr = next, p4d++) {
398 next = p4d_addr_end(addr, end);
402 } else if (p4d_none(*p4d)) {
403 pud = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
406 p4d_populate(&init_mm, p4d, pud);
408 ret = modify_pud_table(p4d, addr, next, add, direct);
412 try_free_pud_table(p4d, addr & P4D_MASK);
419 static void try_free_p4d_table(pgd_t *pgd, unsigned long start)
421 const unsigned long end = start + PGDIR_SIZE;
425 /* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
426 if (end > VMALLOC_START)
429 if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end)
433 p4d = p4d_offset(pgd, start);
434 for (i = 0; i < PTRS_PER_P4D; i++, p4d++) {
438 vmem_free_pages(pgd_deref(*pgd), CRST_ALLOC_ORDER);
442 static int modify_pagetable(unsigned long start, unsigned long end, bool add,
445 unsigned long addr, next;
450 if (WARN_ON_ONCE(!PAGE_ALIGNED(start | end)))
452 for (addr = start; addr < end; addr = next) {
453 next = pgd_addr_end(addr, end);
454 pgd = pgd_offset_k(addr);
459 } else if (pgd_none(*pgd)) {
460 p4d = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
463 pgd_populate(&init_mm, pgd, p4d);
465 ret = modify_p4d_table(pgd, addr, next, add, direct);
469 try_free_p4d_table(pgd, addr & PGDIR_MASK);
474 flush_tlb_kernel_range(start, end);
478 static int add_pagetable(unsigned long start, unsigned long end, bool direct)
480 return modify_pagetable(start, end, true, direct);
483 static int remove_pagetable(unsigned long start, unsigned long end, bool direct)
485 return modify_pagetable(start, end, false, direct);
489 * Add a physical memory range to the 1:1 mapping.
491 static int vmem_add_range(unsigned long start, unsigned long size)
493 return add_pagetable(start, start + size, true);
497 * Remove a physical memory range from the 1:1 mapping.
499 static void vmem_remove_range(unsigned long start, unsigned long size)
501 remove_pagetable(start, start + size, true);
505 * Add a backed mem_map array to the virtual mem_map array.
507 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
508 struct vmem_altmap *altmap)
512 mutex_lock(&vmem_mutex);
513 /* We don't care about the node, just use NUMA_NO_NODE on allocations */
514 ret = add_pagetable(start, end, false);
516 remove_pagetable(start, end, false);
517 mutex_unlock(&vmem_mutex);
521 void vmemmap_free(unsigned long start, unsigned long end,
522 struct vmem_altmap *altmap)
524 mutex_lock(&vmem_mutex);
525 remove_pagetable(start, end, false);
526 mutex_unlock(&vmem_mutex);
529 void vmem_remove_mapping(unsigned long start, unsigned long size)
531 mutex_lock(&vmem_mutex);
532 vmem_remove_range(start, size);
533 mutex_unlock(&vmem_mutex);
536 struct range arch_get_mappable_range(void)
538 struct range mhp_range;
541 mhp_range.end = VMEM_MAX_PHYS - 1;
545 int vmem_add_mapping(unsigned long start, unsigned long size)
547 struct range range = arch_get_mappable_range();
550 if (start < range.start ||
551 start + size > range.end + 1 ||
552 start + size < start)
555 mutex_lock(&vmem_mutex);
556 ret = vmem_add_range(start, size);
558 vmem_remove_range(start, size);
559 mutex_unlock(&vmem_mutex);
564 * map whole physical memory to virtual memory (identity mapping)
565 * we reserve enough space in the vmalloc area for vmemmap to hotplug
566 * additional memory segments.
568 void __init vmem_map_init(void)
570 phys_addr_t base, end;
573 for_each_mem_range(i, &base, &end)
574 vmem_add_range(base, end - base);
575 __set_memory((unsigned long)_stext,
576 (unsigned long)(_etext - _stext) >> PAGE_SHIFT,
577 SET_MEMORY_RO | SET_MEMORY_X);
578 __set_memory((unsigned long)_etext,
579 (unsigned long)(__end_rodata - _etext) >> PAGE_SHIFT,
581 __set_memory((unsigned long)_sinittext,
582 (unsigned long)(_einittext - _sinittext) >> PAGE_SHIFT,
583 SET_MEMORY_RO | SET_MEMORY_X);
584 __set_memory(__stext_dma, (__etext_dma - __stext_dma) >> PAGE_SHIFT,
585 SET_MEMORY_RO | SET_MEMORY_X);
587 /* we need lowcore executable for our LPSWE instructions */
590 pr_info("Write protected kernel read-only data: %luk\n",
591 (unsigned long)(__end_rodata - _stext) >> 10);