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/bootmem.h>
10 #include <linux/init.h>
11 #include <linux/list.h>
12 #include <linux/hugetlb.h>
13 #include <linux/slab.h>
14 #include <linux/memblock.h>
15 #include <asm/cacheflush.h>
16 #include <asm/pgalloc.h>
17 #include <asm/pgtable.h>
18 #include <asm/setup.h>
19 #include <asm/tlbflush.h>
20 #include <asm/sections.h>
21 #include <asm/set_memory.h>
23 static DEFINE_MUTEX(vmem_mutex);
25 struct memory_segment {
26 struct list_head list;
31 static LIST_HEAD(mem_segs);
33 static void __ref *vmem_alloc_pages(unsigned int order)
35 unsigned long size = PAGE_SIZE << order;
37 if (slab_is_available())
38 return (void *)__get_free_pages(GFP_KERNEL, order);
39 return (void *) memblock_alloc(size, size);
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 clear_table((unsigned long *) pte, _PAGE_INVALID, size);
68 * Add a physical memory range to the 1:1 mapping.
70 static int vmem_add_mem(unsigned long start, unsigned long size)
72 unsigned long pgt_prot, sgt_prot, r3_prot;
73 unsigned long pages4k, pages1m, pages2g;
74 unsigned long end = start + size;
75 unsigned long address = start;
83 pgt_prot = pgprot_val(PAGE_KERNEL);
84 sgt_prot = pgprot_val(SEGMENT_KERNEL);
85 r3_prot = pgprot_val(REGION3_KERNEL);
86 if (!MACHINE_HAS_NX) {
87 pgt_prot &= ~_PAGE_NOEXEC;
88 sgt_prot &= ~_SEGMENT_ENTRY_NOEXEC;
89 r3_prot &= ~_REGION_ENTRY_NOEXEC;
91 pages4k = pages1m = pages2g = 0;
92 while (address < end) {
93 pg_dir = pgd_offset_k(address);
94 if (pgd_none(*pg_dir)) {
95 p4_dir = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
98 pgd_populate(&init_mm, pg_dir, p4_dir);
100 p4_dir = p4d_offset(pg_dir, address);
101 if (p4d_none(*p4_dir)) {
102 pu_dir = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
105 p4d_populate(&init_mm, p4_dir, pu_dir);
107 pu_dir = pud_offset(p4_dir, address);
108 if (MACHINE_HAS_EDAT2 && pud_none(*pu_dir) && address &&
109 !(address & ~PUD_MASK) && (address + PUD_SIZE <= end) &&
110 !debug_pagealloc_enabled()) {
111 pud_val(*pu_dir) = address | r3_prot;
116 if (pud_none(*pu_dir)) {
117 pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
120 pud_populate(&init_mm, pu_dir, pm_dir);
122 pm_dir = pmd_offset(pu_dir, address);
123 if (MACHINE_HAS_EDAT1 && pmd_none(*pm_dir) && address &&
124 !(address & ~PMD_MASK) && (address + PMD_SIZE <= end) &&
125 !debug_pagealloc_enabled()) {
126 pmd_val(*pm_dir) = address | sgt_prot;
131 if (pmd_none(*pm_dir)) {
132 pt_dir = vmem_pte_alloc();
135 pmd_populate(&init_mm, pm_dir, pt_dir);
138 pt_dir = pte_offset_kernel(pm_dir, address);
139 pte_val(*pt_dir) = address | pgt_prot;
140 address += PAGE_SIZE;
145 update_page_count(PG_DIRECT_MAP_4K, pages4k);
146 update_page_count(PG_DIRECT_MAP_1M, pages1m);
147 update_page_count(PG_DIRECT_MAP_2G, pages2g);
152 * Remove a physical memory range from the 1:1 mapping.
153 * Currently only invalidates page table entries.
155 static void vmem_remove_range(unsigned long start, unsigned long size)
157 unsigned long pages4k, pages1m, pages2g;
158 unsigned long end = start + size;
159 unsigned long address = start;
166 pages4k = pages1m = pages2g = 0;
167 while (address < end) {
168 pg_dir = pgd_offset_k(address);
169 if (pgd_none(*pg_dir)) {
170 address += PGDIR_SIZE;
173 p4_dir = p4d_offset(pg_dir, address);
174 if (p4d_none(*p4_dir)) {
178 pu_dir = pud_offset(p4_dir, address);
179 if (pud_none(*pu_dir)) {
183 if (pud_large(*pu_dir)) {
189 pm_dir = pmd_offset(pu_dir, address);
190 if (pmd_none(*pm_dir)) {
194 if (pmd_large(*pm_dir)) {
200 pt_dir = pte_offset_kernel(pm_dir, address);
201 pte_clear(&init_mm, address, pt_dir);
202 address += PAGE_SIZE;
205 flush_tlb_kernel_range(start, end);
206 update_page_count(PG_DIRECT_MAP_4K, -pages4k);
207 update_page_count(PG_DIRECT_MAP_1M, -pages1m);
208 update_page_count(PG_DIRECT_MAP_2G, -pages2g);
212 * Add a backed mem_map array to the virtual mem_map array.
214 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
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)
304 * Add memory segment to the segment list if it doesn't overlap with
305 * an already present segment.
307 static int insert_memory_segment(struct memory_segment *seg)
309 struct memory_segment *tmp;
311 if (seg->start + seg->size > VMEM_MAX_PHYS ||
312 seg->start + seg->size < seg->start)
315 list_for_each_entry(tmp, &mem_segs, list) {
316 if (seg->start >= tmp->start + tmp->size)
318 if (seg->start + seg->size <= tmp->start)
322 list_add(&seg->list, &mem_segs);
327 * Remove memory segment from the segment list.
329 static void remove_memory_segment(struct memory_segment *seg)
331 list_del(&seg->list);
334 static void __remove_shared_memory(struct memory_segment *seg)
336 remove_memory_segment(seg);
337 vmem_remove_range(seg->start, seg->size);
340 int vmem_remove_mapping(unsigned long start, unsigned long size)
342 struct memory_segment *seg;
345 mutex_lock(&vmem_mutex);
348 list_for_each_entry(seg, &mem_segs, list) {
349 if (seg->start == start && seg->size == size)
353 if (seg->start != start || seg->size != size)
357 __remove_shared_memory(seg);
360 mutex_unlock(&vmem_mutex);
364 int vmem_add_mapping(unsigned long start, unsigned long size)
366 struct memory_segment *seg;
369 mutex_lock(&vmem_mutex);
371 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
377 ret = insert_memory_segment(seg);
381 ret = vmem_add_mem(start, size);
387 __remove_shared_memory(seg);
391 mutex_unlock(&vmem_mutex);
396 * map whole physical memory to virtual memory (identity mapping)
397 * we reserve enough space in the vmalloc area for vmemmap to hotplug
398 * additional memory segments.
400 void __init vmem_map_init(void)
402 struct memblock_region *reg;
404 for_each_memblock(memory, reg)
405 vmem_add_mem(reg->base, reg->size);
406 __set_memory((unsigned long) _stext,
407 (_etext - _stext) >> PAGE_SHIFT,
408 SET_MEMORY_RO | SET_MEMORY_X);
409 __set_memory((unsigned long) _etext,
410 (_eshared - _etext) >> PAGE_SHIFT,
412 __set_memory((unsigned long) _sinittext,
413 (_einittext - _sinittext) >> PAGE_SHIFT,
414 SET_MEMORY_RO | SET_MEMORY_X);
415 pr_info("Write protected kernel read-only data: %luk\n",
416 (_eshared - _stext) >> 10);
420 * Convert memblock.memory to a memory segment list so there is a single
421 * list that contains all memory segments.
423 static int __init vmem_convert_memory_chunk(void)
425 struct memblock_region *reg;
426 struct memory_segment *seg;
428 mutex_lock(&vmem_mutex);
429 for_each_memblock(memory, reg) {
430 seg = kzalloc(sizeof(*seg), GFP_KERNEL);
432 panic("Out of memory...\n");
433 seg->start = reg->base;
434 seg->size = reg->size;
435 insert_memory_segment(seg);
437 mutex_unlock(&vmem_mutex);
441 core_initcall(vmem_convert_memory_chunk);