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/memblock.h>
10 #include <linux/init.h>
11 #include <linux/list.h>
12 #include <linux/hugetlb.h>
13 #include <linux/slab.h>
14 #include <asm/cacheflush.h>
15 #include <asm/pgalloc.h>
16 #include <asm/pgtable.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 struct memory_segment {
25 struct list_head list;
30 static LIST_HEAD(mem_segs);
32 static void __ref *vmem_alloc_pages(unsigned int order)
34 unsigned long size = PAGE_SIZE << order;
36 if (slab_is_available())
37 return (void *)__get_free_pages(GFP_KERNEL, order);
38 return (void *) memblock_phys_alloc(size, size);
41 void *vmem_crst_alloc(unsigned long val)
45 table = vmem_alloc_pages(CRST_ALLOC_ORDER);
47 crst_table_init(table, val);
51 pte_t __ref *vmem_pte_alloc(void)
53 unsigned long size = PTRS_PER_PTE * sizeof(pte_t);
56 if (slab_is_available())
57 pte = (pte_t *) page_table_alloc(&init_mm);
59 pte = (pte_t *) memblock_phys_alloc(size, size);
62 memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE);
67 * Add a physical memory range to the 1:1 mapping.
69 static int vmem_add_mem(unsigned long start, unsigned long size)
71 unsigned long pgt_prot, sgt_prot, r3_prot;
72 unsigned long pages4k, pages1m, pages2g;
73 unsigned long end = start + size;
74 unsigned long address = start;
82 pgt_prot = pgprot_val(PAGE_KERNEL);
83 sgt_prot = pgprot_val(SEGMENT_KERNEL);
84 r3_prot = pgprot_val(REGION3_KERNEL);
85 if (!MACHINE_HAS_NX) {
86 pgt_prot &= ~_PAGE_NOEXEC;
87 sgt_prot &= ~_SEGMENT_ENTRY_NOEXEC;
88 r3_prot &= ~_REGION_ENTRY_NOEXEC;
90 pages4k = pages1m = pages2g = 0;
91 while (address < end) {
92 pg_dir = pgd_offset_k(address);
93 if (pgd_none(*pg_dir)) {
94 p4_dir = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
97 pgd_populate(&init_mm, pg_dir, p4_dir);
99 p4_dir = p4d_offset(pg_dir, address);
100 if (p4d_none(*p4_dir)) {
101 pu_dir = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
104 p4d_populate(&init_mm, p4_dir, pu_dir);
106 pu_dir = pud_offset(p4_dir, address);
107 if (MACHINE_HAS_EDAT2 && pud_none(*pu_dir) && address &&
108 !(address & ~PUD_MASK) && (address + PUD_SIZE <= end) &&
109 !debug_pagealloc_enabled()) {
110 pud_val(*pu_dir) = address | r3_prot;
115 if (pud_none(*pu_dir)) {
116 pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
119 pud_populate(&init_mm, pu_dir, pm_dir);
121 pm_dir = pmd_offset(pu_dir, address);
122 if (MACHINE_HAS_EDAT1 && pmd_none(*pm_dir) && address &&
123 !(address & ~PMD_MASK) && (address + PMD_SIZE <= end) &&
124 !debug_pagealloc_enabled()) {
125 pmd_val(*pm_dir) = address | sgt_prot;
130 if (pmd_none(*pm_dir)) {
131 pt_dir = vmem_pte_alloc();
134 pmd_populate(&init_mm, pm_dir, pt_dir);
137 pt_dir = pte_offset_kernel(pm_dir, address);
138 pte_val(*pt_dir) = address | pgt_prot;
139 address += PAGE_SIZE;
144 update_page_count(PG_DIRECT_MAP_4K, pages4k);
145 update_page_count(PG_DIRECT_MAP_1M, pages1m);
146 update_page_count(PG_DIRECT_MAP_2G, pages2g);
151 * Remove a physical memory range from the 1:1 mapping.
152 * Currently only invalidates page table entries.
154 static void vmem_remove_range(unsigned long start, unsigned long size)
156 unsigned long pages4k, pages1m, pages2g;
157 unsigned long end = start + size;
158 unsigned long address = start;
165 pages4k = pages1m = pages2g = 0;
166 while (address < end) {
167 pg_dir = pgd_offset_k(address);
168 if (pgd_none(*pg_dir)) {
169 address += PGDIR_SIZE;
172 p4_dir = p4d_offset(pg_dir, address);
173 if (p4d_none(*p4_dir)) {
177 pu_dir = pud_offset(p4_dir, address);
178 if (pud_none(*pu_dir)) {
182 if (pud_large(*pu_dir)) {
188 pm_dir = pmd_offset(pu_dir, address);
189 if (pmd_none(*pm_dir)) {
193 if (pmd_large(*pm_dir)) {
199 pt_dir = pte_offset_kernel(pm_dir, address);
200 pte_clear(&init_mm, address, pt_dir);
201 address += PAGE_SIZE;
204 flush_tlb_kernel_range(start, end);
205 update_page_count(PG_DIRECT_MAP_4K, -pages4k);
206 update_page_count(PG_DIRECT_MAP_1M, -pages1m);
207 update_page_count(PG_DIRECT_MAP_2G, -pages2g);
211 * Add a backed mem_map array to the virtual mem_map array.
213 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
214 struct vmem_altmap *altmap)
216 unsigned long pgt_prot, sgt_prot;
217 unsigned long address = start;
225 pgt_prot = pgprot_val(PAGE_KERNEL);
226 sgt_prot = pgprot_val(SEGMENT_KERNEL);
227 if (!MACHINE_HAS_NX) {
228 pgt_prot &= ~_PAGE_NOEXEC;
229 sgt_prot &= ~_SEGMENT_ENTRY_NOEXEC;
231 for (address = start; address < end;) {
232 pg_dir = pgd_offset_k(address);
233 if (pgd_none(*pg_dir)) {
234 p4_dir = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
237 pgd_populate(&init_mm, pg_dir, p4_dir);
240 p4_dir = p4d_offset(pg_dir, address);
241 if (p4d_none(*p4_dir)) {
242 pu_dir = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
245 p4d_populate(&init_mm, p4_dir, pu_dir);
248 pu_dir = pud_offset(p4_dir, address);
249 if (pud_none(*pu_dir)) {
250 pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
253 pud_populate(&init_mm, pu_dir, pm_dir);
256 pm_dir = pmd_offset(pu_dir, address);
257 if (pmd_none(*pm_dir)) {
258 /* Use 1MB frames for vmemmap if available. We always
259 * use large frames even if they are only partially
261 * Otherwise we would have also page tables since
262 * vmemmap_populate gets called for each section
264 if (MACHINE_HAS_EDAT1) {
267 new_page = vmemmap_alloc_block(PMD_SIZE, node);
270 pmd_val(*pm_dir) = __pa(new_page) | sgt_prot;
271 address = (address + PMD_SIZE) & PMD_MASK;
274 pt_dir = vmem_pte_alloc();
277 pmd_populate(&init_mm, pm_dir, pt_dir);
278 } else if (pmd_large(*pm_dir)) {
279 address = (address + PMD_SIZE) & PMD_MASK;
283 pt_dir = pte_offset_kernel(pm_dir, address);
284 if (pte_none(*pt_dir)) {
287 new_page = vmemmap_alloc_block(PAGE_SIZE, node);
290 pte_val(*pt_dir) = __pa(new_page) | pgt_prot;
292 address += PAGE_SIZE;
299 void vmemmap_free(unsigned long start, unsigned long end,
300 struct vmem_altmap *altmap)
305 * Add memory segment to the segment list if it doesn't overlap with
306 * an already present segment.
308 static int insert_memory_segment(struct memory_segment *seg)
310 struct memory_segment *tmp;
312 if (seg->start + seg->size > VMEM_MAX_PHYS ||
313 seg->start + seg->size < seg->start)
316 list_for_each_entry(tmp, &mem_segs, list) {
317 if (seg->start >= tmp->start + tmp->size)
319 if (seg->start + seg->size <= tmp->start)
323 list_add(&seg->list, &mem_segs);
328 * Remove memory segment from the segment list.
330 static void remove_memory_segment(struct memory_segment *seg)
332 list_del(&seg->list);
335 static void __remove_shared_memory(struct memory_segment *seg)
337 remove_memory_segment(seg);
338 vmem_remove_range(seg->start, seg->size);
341 int vmem_remove_mapping(unsigned long start, unsigned long size)
343 struct memory_segment *seg;
346 mutex_lock(&vmem_mutex);
349 list_for_each_entry(seg, &mem_segs, list) {
350 if (seg->start == start && seg->size == size)
354 if (seg->start != start || seg->size != size)
358 __remove_shared_memory(seg);
361 mutex_unlock(&vmem_mutex);
365 int vmem_add_mapping(unsigned long start, unsigned long size)
367 struct memory_segment *seg;
370 mutex_lock(&vmem_mutex);
372 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
378 ret = insert_memory_segment(seg);
382 ret = vmem_add_mem(start, size);
388 __remove_shared_memory(seg);
392 mutex_unlock(&vmem_mutex);
397 * map whole physical memory to virtual memory (identity mapping)
398 * we reserve enough space in the vmalloc area for vmemmap to hotplug
399 * additional memory segments.
401 void __init vmem_map_init(void)
403 struct memblock_region *reg;
405 for_each_memblock(memory, reg)
406 vmem_add_mem(reg->base, reg->size);
407 __set_memory((unsigned long)_stext,
408 (unsigned long)(_etext - _stext) >> PAGE_SHIFT,
409 SET_MEMORY_RO | SET_MEMORY_X);
410 __set_memory((unsigned long)_etext,
411 (unsigned long)(__end_rodata - _etext) >> PAGE_SHIFT,
413 __set_memory((unsigned long)_sinittext,
414 (unsigned long)(_einittext - _sinittext) >> PAGE_SHIFT,
415 SET_MEMORY_RO | SET_MEMORY_X);
416 __set_memory(__stext_dma, (__etext_dma - __stext_dma) >> PAGE_SHIFT,
417 SET_MEMORY_RO | SET_MEMORY_X);
418 pr_info("Write protected kernel read-only data: %luk\n",
419 (unsigned long)(__end_rodata - _stext) >> 10);
423 * Convert memblock.memory to a memory segment list so there is a single
424 * list that contains all memory segments.
426 static int __init vmem_convert_memory_chunk(void)
428 struct memblock_region *reg;
429 struct memory_segment *seg;
431 mutex_lock(&vmem_mutex);
432 for_each_memblock(memory, reg) {
433 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
435 panic("Out of memory...\n");
436 seg->start = reg->base;
437 seg->size = reg->size;
438 insert_memory_segment(seg);
440 mutex_unlock(&vmem_mutex);
444 core_initcall(vmem_convert_memory_chunk);