1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/arch/arm/mm/init.c
5 * Copyright (C) 1995-2005 Russell King
7 #include <linux/kernel.h>
8 #include <linux/errno.h>
9 #include <linux/swap.h>
10 #include <linux/init.h>
11 #include <linux/mman.h>
12 #include <linux/sched/signal.h>
13 #include <linux/sched/task.h>
14 #include <linux/export.h>
15 #include <linux/nodemask.h>
16 #include <linux/initrd.h>
17 #include <linux/of_fdt.h>
18 #include <linux/highmem.h>
19 #include <linux/gfp.h>
20 #include <linux/memblock.h>
21 #include <linux/dma-map-ops.h>
22 #include <linux/sizes.h>
23 #include <linux/stop_machine.h>
24 #include <linux/swiotlb.h>
27 #include <asm/mach-types.h>
28 #include <asm/memblock.h>
29 #include <asm/memory.h>
31 #include <asm/sections.h>
32 #include <asm/setup.h>
33 #include <asm/set_memory.h>
34 #include <asm/system_info.h>
36 #include <asm/fixmap.h>
37 #include <asm/ptdump.h>
39 #include <asm/mach/arch.h>
40 #include <asm/mach/map.h>
44 #ifdef CONFIG_CPU_CP15_MMU
45 unsigned long __init __clear_cr(unsigned long mask)
47 cr_alignment = cr_alignment & ~mask;
52 #ifdef CONFIG_BLK_DEV_INITRD
53 static int __init parse_tag_initrd(const struct tag *tag)
55 pr_warn("ATAG_INITRD is deprecated; "
56 "please update your bootloader.\n");
57 phys_initrd_start = __virt_to_phys(tag->u.initrd.start);
58 phys_initrd_size = tag->u.initrd.size;
62 __tagtable(ATAG_INITRD, parse_tag_initrd);
64 static int __init parse_tag_initrd2(const struct tag *tag)
66 phys_initrd_start = tag->u.initrd.start;
67 phys_initrd_size = tag->u.initrd.size;
71 __tagtable(ATAG_INITRD2, parse_tag_initrd2);
74 static void __init find_limits(unsigned long *min, unsigned long *max_low,
75 unsigned long *max_high)
77 *max_low = PFN_DOWN(memblock_get_current_limit());
78 *min = PFN_UP(memblock_start_of_DRAM());
79 *max_high = PFN_DOWN(memblock_end_of_DRAM());
82 #ifdef CONFIG_ZONE_DMA
84 phys_addr_t arm_dma_zone_size __read_mostly;
85 EXPORT_SYMBOL(arm_dma_zone_size);
88 * The DMA mask corresponding to the maximum bus address allocatable
89 * using GFP_DMA. The default here places no restriction on DMA
90 * allocations. This must be the smallest DMA mask in the system,
91 * so a successful GFP_DMA allocation will always satisfy this.
93 phys_addr_t arm_dma_limit;
94 unsigned long arm_dma_pfn_limit;
97 void __init setup_dma_zone(const struct machine_desc *mdesc)
99 #ifdef CONFIG_ZONE_DMA
100 if (mdesc->dma_zone_size) {
101 arm_dma_zone_size = mdesc->dma_zone_size;
102 arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
104 arm_dma_limit = 0xffffffff;
105 arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT;
109 static void __init zone_sizes_init(unsigned long min, unsigned long max_low,
110 unsigned long max_high)
112 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
114 #ifdef CONFIG_ZONE_DMA
115 max_zone_pfn[ZONE_DMA] = min(arm_dma_pfn_limit, max_low);
117 max_zone_pfn[ZONE_NORMAL] = max_low;
118 #ifdef CONFIG_HIGHMEM
119 max_zone_pfn[ZONE_HIGHMEM] = max_high;
121 free_area_init(max_zone_pfn);
124 #ifdef CONFIG_HAVE_ARCH_PFN_VALID
125 int pfn_valid(unsigned long pfn)
127 phys_addr_t addr = __pfn_to_phys(pfn);
128 unsigned long pageblock_size = PAGE_SIZE * pageblock_nr_pages;
130 if (__phys_to_pfn(addr) != pfn)
134 * If address less than pageblock_size bytes away from a present
135 * memory chunk there still will be a memory map entry for it
136 * because we round freed memory map to the pageblock boundaries.
138 if (memblock_overlaps_region(&memblock.memory,
139 ALIGN_DOWN(addr, pageblock_size),
145 EXPORT_SYMBOL(pfn_valid);
148 static bool arm_memblock_steal_permitted = true;
150 phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
154 BUG_ON(!arm_memblock_steal_permitted);
156 phys = memblock_phys_alloc(size, align);
158 panic("Failed to steal %pa bytes at %pS\n",
159 &size, (void *)_RET_IP_);
161 memblock_free(phys, size);
162 memblock_remove(phys, size);
167 static void __init arm_initrd_init(void)
169 #ifdef CONFIG_BLK_DEV_INITRD
173 initrd_start = initrd_end = 0;
175 if (!phys_initrd_size)
179 * Round the memory region to page boundaries as per free_initrd_mem()
180 * This allows us to detect whether the pages overlapping the initrd
181 * are in use, but more importantly, reserves the entire set of pages
182 * as we don't want these pages allocated for other purposes.
184 start = round_down(phys_initrd_start, PAGE_SIZE);
185 size = phys_initrd_size + (phys_initrd_start - start);
186 size = round_up(size, PAGE_SIZE);
188 if (!memblock_is_region_memory(start, size)) {
189 pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",
194 if (memblock_is_region_reserved(start, size)) {
195 pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
200 memblock_reserve(start, size);
202 /* Now convert initrd to virtual addresses */
203 initrd_start = __phys_to_virt(phys_initrd_start);
204 initrd_end = initrd_start + phys_initrd_size;
208 #ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND
209 void check_cpu_icache_size(int cpuid)
213 asm("mrc p15, 0, %0, c0, c0, 1" : "=r" (ctr));
215 size = 1 << ((ctr & 0xf) + 2);
216 if (cpuid != 0 && icache_size != size)
217 pr_info("CPU%u: detected I-Cache line size mismatch, workaround enabled\n",
219 if (icache_size > size)
224 void __init arm_memblock_init(const struct machine_desc *mdesc)
226 /* Register the kernel text, kernel data and initrd with memblock. */
227 memblock_reserve(__pa(KERNEL_START), KERNEL_END - KERNEL_START);
231 arm_mm_memblock_reserve();
233 /* reserve any platform specific memblock areas */
237 early_init_fdt_scan_reserved_mem();
239 /* reserve memory for DMA contiguous allocations */
240 dma_contiguous_reserve(arm_dma_limit);
242 arm_memblock_steal_permitted = false;
246 void __init bootmem_init(void)
248 memblock_allow_resize();
250 find_limits(&min_low_pfn, &max_low_pfn, &max_pfn);
252 early_memtest((phys_addr_t)min_low_pfn << PAGE_SHIFT,
253 (phys_addr_t)max_low_pfn << PAGE_SHIFT);
256 * sparse_init() tries to allocate memory from memblock, so must be
257 * done after the fixed reservations
262 * Now free the memory - free_area_init needs
263 * the sparse mem_map arrays initialized by sparse_init()
264 * for memmap_init_zone(), otherwise all PFNs are invalid.
266 zone_sizes_init(min_low_pfn, max_low_pfn, max_pfn);
270 * Poison init memory with an undefined instruction (ARM) or a branch to an
271 * undefined instruction (Thumb).
273 static inline void poison_init_mem(void *s, size_t count)
276 for (; count != 0; count -= 4)
280 static void __init free_highpages(void)
282 #ifdef CONFIG_HIGHMEM
283 unsigned long max_low = max_low_pfn;
284 phys_addr_t range_start, range_end;
287 /* set highmem page free */
288 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
289 &range_start, &range_end, NULL) {
290 unsigned long start = PFN_UP(range_start);
291 unsigned long end = PFN_DOWN(range_end);
293 /* Ignore complete lowmem entries */
297 /* Truncate partial highmem entries */
301 for (; start < end; start++)
302 free_highmem_page(pfn_to_page(start));
308 * mem_init() marks the free areas in the mem_map and tells us how much
309 * memory is free. This is done after various parts of the system have
310 * claimed their memory after the kernel image.
312 void __init mem_init(void)
314 #ifdef CONFIG_ARM_LPAE
315 if (swiotlb_force == SWIOTLB_FORCE ||
316 max_pfn > arm_dma_pfn_limit)
319 swiotlb_force = SWIOTLB_NO_FORCE;
322 set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
324 /* this will put all unused low memory onto the freelists */
328 /* now that our DMA memory is actually so designated, we can free it */
329 free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
335 * Check boundaries twice: Some fundamental inconsistencies can
336 * be detected at build time already.
339 BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR);
340 BUG_ON(TASK_SIZE > MODULES_VADDR);
343 #ifdef CONFIG_HIGHMEM
344 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
345 BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
349 #ifdef CONFIG_STRICT_KERNEL_RWX
350 struct section_perm {
359 /* First section-aligned location at or after __start_rodata. */
360 extern char __start_rodata_section_aligned[];
362 static struct section_perm nx_perms[] = {
363 /* Make pages tables, etc before _stext RW (set NX). */
365 .name = "pre-text NX",
366 .start = PAGE_OFFSET,
367 .end = (unsigned long)_stext,
368 .mask = ~PMD_SECT_XN,
371 /* Make init RW (set NX). */
374 .start = (unsigned long)__init_begin,
375 .end = (unsigned long)_sdata,
376 .mask = ~PMD_SECT_XN,
379 /* Make rodata NX (set RO in ro_perms below). */
382 .start = (unsigned long)__start_rodata_section_aligned,
383 .end = (unsigned long)__init_begin,
384 .mask = ~PMD_SECT_XN,
389 static struct section_perm ro_perms[] = {
390 /* Make kernel code and rodata RX (set RO). */
392 .name = "text/rodata RO",
393 .start = (unsigned long)_stext,
394 .end = (unsigned long)__init_begin,
395 #ifdef CONFIG_ARM_LPAE
396 .mask = ~(L_PMD_SECT_RDONLY | PMD_SECT_AP2),
397 .prot = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
399 .mask = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
400 .prot = PMD_SECT_APX | PMD_SECT_AP_WRITE,
401 .clear = PMD_SECT_AP_WRITE,
407 * Updates section permissions only for the current mm (sections are
408 * copied into each mm). During startup, this is the init_mm. Is only
409 * safe to be called with preemption disabled, as under stop_machine().
411 static inline void section_update(unsigned long addr, pmdval_t mask,
412 pmdval_t prot, struct mm_struct *mm)
416 pmd = pmd_offset(pud_offset(p4d_offset(pgd_offset(mm, addr), addr), addr), addr);
418 #ifdef CONFIG_ARM_LPAE
419 pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
421 if (addr & SECTION_SIZE)
422 pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
424 pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
426 flush_pmd_entry(pmd);
427 local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
430 /* Make sure extended page tables are in use. */
431 static inline bool arch_has_strict_perms(void)
433 if (cpu_architecture() < CPU_ARCH_ARMv6)
436 return !!(get_cr() & CR_XP);
439 static void set_section_perms(struct section_perm *perms, int n, bool set,
440 struct mm_struct *mm)
445 if (!arch_has_strict_perms())
448 for (i = 0; i < n; i++) {
449 if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
450 !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
451 pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
452 perms[i].name, perms[i].start, perms[i].end,
457 for (addr = perms[i].start;
459 addr += SECTION_SIZE)
460 section_update(addr, perms[i].mask,
461 set ? perms[i].prot : perms[i].clear, mm);
467 * update_sections_early intended to be called only through stop_machine
468 * framework and executed by only one CPU while all other CPUs will spin and
469 * wait, so no locking is required in this function.
471 static void update_sections_early(struct section_perm perms[], int n)
473 struct task_struct *t, *s;
475 for_each_process(t) {
476 if (t->flags & PF_KTHREAD)
478 for_each_thread(t, s)
480 set_section_perms(perms, n, true, s->mm);
482 set_section_perms(perms, n, true, current->active_mm);
483 set_section_perms(perms, n, true, &init_mm);
486 static int __fix_kernmem_perms(void *unused)
488 update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
492 static void fix_kernmem_perms(void)
494 stop_machine(__fix_kernmem_perms, NULL, NULL);
497 static int __mark_rodata_ro(void *unused)
499 update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
503 void mark_rodata_ro(void)
505 stop_machine(__mark_rodata_ro, NULL, NULL);
510 static inline void fix_kernmem_perms(void) { }
511 #endif /* CONFIG_STRICT_KERNEL_RWX */
513 void free_initmem(void)
517 poison_init_mem(__init_begin, __init_end - __init_begin);
518 if (!machine_is_integrator() && !machine_is_cintegrator())
519 free_initmem_default(-1);
522 #ifdef CONFIG_BLK_DEV_INITRD
523 void free_initrd_mem(unsigned long start, unsigned long end)
525 if (start == initrd_start)
526 start = round_down(start, PAGE_SIZE);
527 if (end == initrd_end)
528 end = round_up(end, PAGE_SIZE);
530 poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
531 free_reserved_area((void *)start, (void *)end, -1, "initrd");