2 * linux/arch/arm/mm/init.c
4 * Copyright (C) 1995-2005 Russell King
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 #include <linux/kernel.h>
11 #include <linux/errno.h>
12 #include <linux/swap.h>
13 #include <linux/init.h>
14 #include <linux/mman.h>
15 #include <linux/sched/signal.h>
16 #include <linux/sched/task.h>
17 #include <linux/export.h>
18 #include <linux/nodemask.h>
19 #include <linux/initrd.h>
20 #include <linux/of_fdt.h>
21 #include <linux/highmem.h>
22 #include <linux/gfp.h>
23 #include <linux/memblock.h>
24 #include <linux/dma-contiguous.h>
25 #include <linux/sizes.h>
26 #include <linux/stop_machine.h>
29 #include <asm/mach-types.h>
30 #include <asm/memblock.h>
31 #include <asm/memory.h>
33 #include <asm/sections.h>
34 #include <asm/setup.h>
35 #include <asm/system_info.h>
37 #include <asm/fixmap.h>
38 #include <asm/ptdump.h>
40 #include <asm/mach/arch.h>
41 #include <asm/mach/map.h>
45 #ifdef CONFIG_CPU_CP15_MMU
46 unsigned long __init __clear_cr(unsigned long mask)
48 cr_alignment = cr_alignment & ~mask;
53 #ifdef CONFIG_BLK_DEV_INITRD
54 static int __init parse_tag_initrd(const struct tag *tag)
56 pr_warn("ATAG_INITRD is deprecated; "
57 "please update your bootloader.\n");
58 phys_initrd_start = __virt_to_phys(tag->u.initrd.start);
59 phys_initrd_size = tag->u.initrd.size;
63 __tagtable(ATAG_INITRD, parse_tag_initrd);
65 static int __init parse_tag_initrd2(const struct tag *tag)
67 phys_initrd_start = tag->u.initrd.start;
68 phys_initrd_size = tag->u.initrd.size;
72 __tagtable(ATAG_INITRD2, parse_tag_initrd2);
75 static void __init find_limits(unsigned long *min, unsigned long *max_low,
76 unsigned long *max_high)
78 *max_low = PFN_DOWN(memblock_get_current_limit());
79 *min = PFN_UP(memblock_start_of_DRAM());
80 *max_high = PFN_DOWN(memblock_end_of_DRAM());
83 #ifdef CONFIG_ZONE_DMA
85 phys_addr_t arm_dma_zone_size __read_mostly;
86 EXPORT_SYMBOL(arm_dma_zone_size);
89 * The DMA mask corresponding to the maximum bus address allocatable
90 * using GFP_DMA. The default here places no restriction on DMA
91 * allocations. This must be the smallest DMA mask in the system,
92 * so a successful GFP_DMA allocation will always satisfy this.
94 phys_addr_t arm_dma_limit;
95 unsigned long arm_dma_pfn_limit;
97 static void __init arm_adjust_dma_zone(unsigned long *size, unsigned long *hole,
98 unsigned long dma_size)
100 if (size[0] <= dma_size)
103 size[ZONE_NORMAL] = size[0] - dma_size;
104 size[ZONE_DMA] = dma_size;
105 hole[ZONE_NORMAL] = hole[0];
110 void __init setup_dma_zone(const struct machine_desc *mdesc)
112 #ifdef CONFIG_ZONE_DMA
113 if (mdesc->dma_zone_size) {
114 arm_dma_zone_size = mdesc->dma_zone_size;
115 arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
117 arm_dma_limit = 0xffffffff;
118 arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT;
122 static void __init zone_sizes_init(unsigned long min, unsigned long max_low,
123 unsigned long max_high)
125 unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
126 struct memblock_region *reg;
129 * initialise the zones.
131 memset(zone_size, 0, sizeof(zone_size));
134 * The memory size has already been determined. If we need
135 * to do anything fancy with the allocation of this memory
136 * to the zones, now is the time to do it.
138 zone_size[0] = max_low - min;
139 #ifdef CONFIG_HIGHMEM
140 zone_size[ZONE_HIGHMEM] = max_high - max_low;
144 * Calculate the size of the holes.
145 * holes = node_size - sum(bank_sizes)
147 memcpy(zhole_size, zone_size, sizeof(zhole_size));
148 for_each_memblock(memory, reg) {
149 unsigned long start = memblock_region_memory_base_pfn(reg);
150 unsigned long end = memblock_region_memory_end_pfn(reg);
152 if (start < max_low) {
153 unsigned long low_end = min(end, max_low);
154 zhole_size[0] -= low_end - start;
156 #ifdef CONFIG_HIGHMEM
158 unsigned long high_start = max(start, max_low);
159 zhole_size[ZONE_HIGHMEM] -= end - high_start;
164 #ifdef CONFIG_ZONE_DMA
166 * Adjust the sizes according to any special requirements for
169 if (arm_dma_zone_size)
170 arm_adjust_dma_zone(zone_size, zhole_size,
171 arm_dma_zone_size >> PAGE_SHIFT);
174 free_area_init_node(0, zone_size, min, zhole_size);
177 #ifdef CONFIG_HAVE_ARCH_PFN_VALID
178 int pfn_valid(unsigned long pfn)
180 return memblock_is_map_memory(__pfn_to_phys(pfn));
182 EXPORT_SYMBOL(pfn_valid);
185 static bool arm_memblock_steal_permitted = true;
187 phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
191 BUG_ON(!arm_memblock_steal_permitted);
193 phys = memblock_phys_alloc(size, align);
195 panic("Failed to steal %pa bytes at %pS\n",
196 &size, (void *)_RET_IP_);
198 memblock_free(phys, size);
199 memblock_remove(phys, size);
204 static void __init arm_initrd_init(void)
206 #ifdef CONFIG_BLK_DEV_INITRD
210 initrd_start = initrd_end = 0;
212 if (!phys_initrd_size)
216 * Round the memory region to page boundaries as per free_initrd_mem()
217 * This allows us to detect whether the pages overlapping the initrd
218 * are in use, but more importantly, reserves the entire set of pages
219 * as we don't want these pages allocated for other purposes.
221 start = round_down(phys_initrd_start, PAGE_SIZE);
222 size = phys_initrd_size + (phys_initrd_start - start);
223 size = round_up(size, PAGE_SIZE);
225 if (!memblock_is_region_memory(start, size)) {
226 pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",
231 if (memblock_is_region_reserved(start, size)) {
232 pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
237 memblock_reserve(start, size);
239 /* Now convert initrd to virtual addresses */
240 initrd_start = __phys_to_virt(phys_initrd_start);
241 initrd_end = initrd_start + phys_initrd_size;
245 void __init arm_memblock_init(const struct machine_desc *mdesc)
247 /* Register the kernel text, kernel data and initrd with memblock. */
248 memblock_reserve(__pa(KERNEL_START), KERNEL_END - KERNEL_START);
252 arm_mm_memblock_reserve();
254 /* reserve any platform specific memblock areas */
258 early_init_fdt_reserve_self();
259 early_init_fdt_scan_reserved_mem();
261 /* reserve memory for DMA contiguous allocations */
262 dma_contiguous_reserve(arm_dma_limit);
264 arm_memblock_steal_permitted = false;
268 void __init bootmem_init(void)
270 memblock_allow_resize();
272 find_limits(&min_low_pfn, &max_low_pfn, &max_pfn);
274 early_memtest((phys_addr_t)min_low_pfn << PAGE_SHIFT,
275 (phys_addr_t)max_low_pfn << PAGE_SHIFT);
278 * Sparsemem tries to allocate bootmem in memory_present(),
279 * so must be done after the fixed reservations
284 * sparse_init() needs the bootmem allocator up and running.
289 * Now free the memory - free_area_init_node needs
290 * the sparse mem_map arrays initialized by sparse_init()
291 * for memmap_init_zone(), otherwise all PFNs are invalid.
293 zone_sizes_init(min_low_pfn, max_low_pfn, max_pfn);
297 * Poison init memory with an undefined instruction (ARM) or a branch to an
298 * undefined instruction (Thumb).
300 static inline void poison_init_mem(void *s, size_t count)
303 for (; count != 0; count -= 4)
308 free_memmap(unsigned long start_pfn, unsigned long end_pfn)
310 struct page *start_pg, *end_pg;
311 phys_addr_t pg, pgend;
314 * Convert start_pfn/end_pfn to a struct page pointer.
316 start_pg = pfn_to_page(start_pfn - 1) + 1;
317 end_pg = pfn_to_page(end_pfn - 1) + 1;
320 * Convert to physical addresses, and
321 * round start upwards and end downwards.
323 pg = PAGE_ALIGN(__pa(start_pg));
324 pgend = __pa(end_pg) & PAGE_MASK;
327 * If there are free pages between these,
328 * free the section of the memmap array.
331 memblock_free_early(pg, pgend - pg);
335 * The mem_map array can get very big. Free the unused area of the memory map.
337 static void __init free_unused_memmap(void)
339 unsigned long start, prev_end = 0;
340 struct memblock_region *reg;
343 * This relies on each bank being in address order.
344 * The banks are sorted previously in bootmem_init().
346 for_each_memblock(memory, reg) {
347 start = memblock_region_memory_base_pfn(reg);
349 #ifdef CONFIG_SPARSEMEM
351 * Take care not to free memmap entries that don't exist
352 * due to SPARSEMEM sections which aren't present.
355 ALIGN(prev_end, PAGES_PER_SECTION));
358 * Align down here since the VM subsystem insists that the
359 * memmap entries are valid from the bank start aligned to
360 * MAX_ORDER_NR_PAGES.
362 start = round_down(start, MAX_ORDER_NR_PAGES);
365 * If we had a previous bank, and there is a space
366 * between the current bank and the previous, free it.
368 if (prev_end && prev_end < start)
369 free_memmap(prev_end, start);
372 * Align up here since the VM subsystem insists that the
373 * memmap entries are valid from the bank end aligned to
374 * MAX_ORDER_NR_PAGES.
376 prev_end = ALIGN(memblock_region_memory_end_pfn(reg),
380 #ifdef CONFIG_SPARSEMEM
381 if (!IS_ALIGNED(prev_end, PAGES_PER_SECTION))
382 free_memmap(prev_end,
383 ALIGN(prev_end, PAGES_PER_SECTION));
387 #ifdef CONFIG_HIGHMEM
388 static inline void free_area_high(unsigned long pfn, unsigned long end)
390 for (; pfn < end; pfn++)
391 free_highmem_page(pfn_to_page(pfn));
395 static void __init free_highpages(void)
397 #ifdef CONFIG_HIGHMEM
398 unsigned long max_low = max_low_pfn;
399 struct memblock_region *mem, *res;
401 /* set highmem page free */
402 for_each_memblock(memory, mem) {
403 unsigned long start = memblock_region_memory_base_pfn(mem);
404 unsigned long end = memblock_region_memory_end_pfn(mem);
406 /* Ignore complete lowmem entries */
410 if (memblock_is_nomap(mem))
413 /* Truncate partial highmem entries */
417 /* Find and exclude any reserved regions */
418 for_each_memblock(reserved, res) {
419 unsigned long res_start, res_end;
421 res_start = memblock_region_reserved_base_pfn(res);
422 res_end = memblock_region_reserved_end_pfn(res);
426 if (res_start < start)
432 if (res_start != start)
433 free_area_high(start, res_start);
439 /* And now free anything which remains */
441 free_area_high(start, end);
447 * mem_init() marks the free areas in the mem_map and tells us how much
448 * memory is free. This is done after various parts of the system have
449 * claimed their memory after the kernel image.
451 void __init mem_init(void)
453 #ifdef CONFIG_HAVE_TCM
454 /* These pointers are filled in on TCM detection */
459 set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
461 /* this will put all unused low memory onto the freelists */
462 free_unused_memmap();
466 /* now that our DMA memory is actually so designated, we can free it */
467 free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
472 mem_init_print_info(NULL);
475 * Check boundaries twice: Some fundamental inconsistencies can
476 * be detected at build time already.
479 BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR);
480 BUG_ON(TASK_SIZE > MODULES_VADDR);
483 #ifdef CONFIG_HIGHMEM
484 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
485 BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
489 #ifdef CONFIG_STRICT_KERNEL_RWX
490 struct section_perm {
499 /* First section-aligned location at or after __start_rodata. */
500 extern char __start_rodata_section_aligned[];
502 static struct section_perm nx_perms[] = {
503 /* Make pages tables, etc before _stext RW (set NX). */
505 .name = "pre-text NX",
506 .start = PAGE_OFFSET,
507 .end = (unsigned long)_stext,
508 .mask = ~PMD_SECT_XN,
511 /* Make init RW (set NX). */
514 .start = (unsigned long)__init_begin,
515 .end = (unsigned long)_sdata,
516 .mask = ~PMD_SECT_XN,
519 /* Make rodata NX (set RO in ro_perms below). */
522 .start = (unsigned long)__start_rodata_section_aligned,
523 .end = (unsigned long)__init_begin,
524 .mask = ~PMD_SECT_XN,
529 static struct section_perm ro_perms[] = {
530 /* Make kernel code and rodata RX (set RO). */
532 .name = "text/rodata RO",
533 .start = (unsigned long)_stext,
534 .end = (unsigned long)__init_begin,
535 #ifdef CONFIG_ARM_LPAE
536 .mask = ~(L_PMD_SECT_RDONLY | PMD_SECT_AP2),
537 .prot = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
539 .mask = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
540 .prot = PMD_SECT_APX | PMD_SECT_AP_WRITE,
541 .clear = PMD_SECT_AP_WRITE,
547 * Updates section permissions only for the current mm (sections are
548 * copied into each mm). During startup, this is the init_mm. Is only
549 * safe to be called with preemption disabled, as under stop_machine().
551 static inline void section_update(unsigned long addr, pmdval_t mask,
552 pmdval_t prot, struct mm_struct *mm)
556 pmd = pmd_offset(pud_offset(pgd_offset(mm, addr), addr), addr);
558 #ifdef CONFIG_ARM_LPAE
559 pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
561 if (addr & SECTION_SIZE)
562 pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
564 pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
566 flush_pmd_entry(pmd);
567 local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
570 /* Make sure extended page tables are in use. */
571 static inline bool arch_has_strict_perms(void)
573 if (cpu_architecture() < CPU_ARCH_ARMv6)
576 return !!(get_cr() & CR_XP);
579 void set_section_perms(struct section_perm *perms, int n, bool set,
580 struct mm_struct *mm)
585 if (!arch_has_strict_perms())
588 for (i = 0; i < n; i++) {
589 if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
590 !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
591 pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
592 perms[i].name, perms[i].start, perms[i].end,
597 for (addr = perms[i].start;
599 addr += SECTION_SIZE)
600 section_update(addr, perms[i].mask,
601 set ? perms[i].prot : perms[i].clear, mm);
607 * update_sections_early intended to be called only through stop_machine
608 * framework and executed by only one CPU while all other CPUs will spin and
609 * wait, so no locking is required in this function.
611 static void update_sections_early(struct section_perm perms[], int n)
613 struct task_struct *t, *s;
615 for_each_process(t) {
616 if (t->flags & PF_KTHREAD)
618 for_each_thread(t, s)
619 set_section_perms(perms, n, true, s->mm);
621 set_section_perms(perms, n, true, current->active_mm);
622 set_section_perms(perms, n, true, &init_mm);
625 static int __fix_kernmem_perms(void *unused)
627 update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
631 static void fix_kernmem_perms(void)
633 stop_machine(__fix_kernmem_perms, NULL, NULL);
636 static int __mark_rodata_ro(void *unused)
638 update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
642 static int kernel_set_to_readonly __read_mostly;
644 void mark_rodata_ro(void)
646 kernel_set_to_readonly = 1;
647 stop_machine(__mark_rodata_ro, NULL, NULL);
651 void set_kernel_text_rw(void)
653 if (!kernel_set_to_readonly)
656 set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), false,
660 void set_kernel_text_ro(void)
662 if (!kernel_set_to_readonly)
665 set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), true,
670 static inline void fix_kernmem_perms(void) { }
671 #endif /* CONFIG_STRICT_KERNEL_RWX */
673 void free_initmem(void)
677 poison_init_mem(__init_begin, __init_end - __init_begin);
678 if (!machine_is_integrator() && !machine_is_cintegrator())
679 free_initmem_default(-1);
682 #ifdef CONFIG_BLK_DEV_INITRD
683 void free_initrd_mem(unsigned long start, unsigned long end)
685 if (start == initrd_start)
686 start = round_down(start, PAGE_SIZE);
687 if (end == initrd_end)
688 end = round_up(end, PAGE_SIZE);
690 poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
691 free_reserved_area((void *)start, (void *)end, -1, "initrd");