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_phys_free(phys, size);
162 memblock_remove(phys, size);
167 #ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND
168 void check_cpu_icache_size(int cpuid)
172 asm("mrc p15, 0, %0, c0, c0, 1" : "=r" (ctr));
174 size = 1 << ((ctr & 0xf) + 2);
175 if (cpuid != 0 && icache_size != size)
176 pr_info("CPU%u: detected I-Cache line size mismatch, workaround enabled\n",
178 if (icache_size > size)
183 void __init arm_memblock_init(const struct machine_desc *mdesc)
185 /* Register the kernel text, kernel data and initrd with memblock. */
186 memblock_reserve(__pa(KERNEL_START), KERNEL_END - KERNEL_START);
188 reserve_initrd_mem();
190 arm_mm_memblock_reserve();
192 /* reserve any platform specific memblock areas */
196 early_init_fdt_scan_reserved_mem();
198 /* reserve memory for DMA contiguous allocations */
199 dma_contiguous_reserve(arm_dma_limit);
201 arm_memblock_steal_permitted = false;
205 void __init bootmem_init(void)
207 memblock_allow_resize();
209 find_limits(&min_low_pfn, &max_low_pfn, &max_pfn);
211 early_memtest((phys_addr_t)min_low_pfn << PAGE_SHIFT,
212 (phys_addr_t)max_low_pfn << PAGE_SHIFT);
215 * sparse_init() tries to allocate memory from memblock, so must be
216 * done after the fixed reservations
221 * Now free the memory - free_area_init needs
222 * the sparse mem_map arrays initialized by sparse_init()
223 * for memmap_init_zone(), otherwise all PFNs are invalid.
225 zone_sizes_init(min_low_pfn, max_low_pfn, max_pfn);
229 * Poison init memory with an undefined instruction (ARM) or a branch to an
230 * undefined instruction (Thumb).
232 static inline void poison_init_mem(void *s, size_t count)
235 for (; count != 0; count -= 4)
239 static void __init free_highpages(void)
241 #ifdef CONFIG_HIGHMEM
242 unsigned long max_low = max_low_pfn;
243 phys_addr_t range_start, range_end;
246 /* set highmem page free */
247 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
248 &range_start, &range_end, NULL) {
249 unsigned long start = PFN_UP(range_start);
250 unsigned long end = PFN_DOWN(range_end);
252 /* Ignore complete lowmem entries */
256 /* Truncate partial highmem entries */
260 for (; start < end; start++)
261 free_highmem_page(pfn_to_page(start));
267 * mem_init() marks the free areas in the mem_map and tells us how much
268 * memory is free. This is done after various parts of the system have
269 * claimed their memory after the kernel image.
271 void __init mem_init(void)
273 #ifdef CONFIG_ARM_LPAE
274 swiotlb_init(max_pfn > arm_dma_pfn_limit, SWIOTLB_VERBOSE);
277 set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
279 /* this will put all unused low memory onto the freelists */
283 /* now that our DMA memory is actually so designated, we can free it */
284 free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
290 * Check boundaries twice: Some fundamental inconsistencies can
291 * be detected at build time already.
294 BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR);
295 BUG_ON(TASK_SIZE > MODULES_VADDR);
298 #ifdef CONFIG_HIGHMEM
299 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
300 BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
304 #ifdef CONFIG_STRICT_KERNEL_RWX
305 struct section_perm {
314 /* First section-aligned location at or after __start_rodata. */
315 extern char __start_rodata_section_aligned[];
317 static struct section_perm nx_perms[] = {
318 /* Make pages tables, etc before _stext RW (set NX). */
320 .name = "pre-text NX",
321 .start = PAGE_OFFSET,
322 .end = (unsigned long)_stext,
323 .mask = ~PMD_SECT_XN,
326 /* Make init RW (set NX). */
329 .start = (unsigned long)__init_begin,
330 .end = (unsigned long)_sdata,
331 .mask = ~PMD_SECT_XN,
334 /* Make rodata NX (set RO in ro_perms below). */
337 .start = (unsigned long)__start_rodata_section_aligned,
338 .end = (unsigned long)__init_begin,
339 .mask = ~PMD_SECT_XN,
344 static struct section_perm ro_perms[] = {
345 /* Make kernel code and rodata RX (set RO). */
347 .name = "text/rodata RO",
348 .start = (unsigned long)_stext,
349 .end = (unsigned long)__init_begin,
350 #ifdef CONFIG_ARM_LPAE
351 .mask = ~(L_PMD_SECT_RDONLY | PMD_SECT_AP2),
352 .prot = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
354 .mask = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
355 .prot = PMD_SECT_APX | PMD_SECT_AP_WRITE,
356 .clear = PMD_SECT_AP_WRITE,
362 * Updates section permissions only for the current mm (sections are
363 * copied into each mm). During startup, this is the init_mm. Is only
364 * safe to be called with preemption disabled, as under stop_machine().
366 static inline void section_update(unsigned long addr, pmdval_t mask,
367 pmdval_t prot, struct mm_struct *mm)
371 pmd = pmd_offset(pud_offset(p4d_offset(pgd_offset(mm, addr), addr), addr), addr);
373 #ifdef CONFIG_ARM_LPAE
374 pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
376 if (addr & SECTION_SIZE)
377 pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
379 pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
381 flush_pmd_entry(pmd);
382 local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
385 /* Make sure extended page tables are in use. */
386 static inline bool arch_has_strict_perms(void)
388 if (cpu_architecture() < CPU_ARCH_ARMv6)
391 return !!(get_cr() & CR_XP);
394 static void set_section_perms(struct section_perm *perms, int n, bool set,
395 struct mm_struct *mm)
400 if (!arch_has_strict_perms())
403 for (i = 0; i < n; i++) {
404 if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
405 !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
406 pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
407 perms[i].name, perms[i].start, perms[i].end,
412 for (addr = perms[i].start;
414 addr += SECTION_SIZE)
415 section_update(addr, perms[i].mask,
416 set ? perms[i].prot : perms[i].clear, mm);
422 * update_sections_early intended to be called only through stop_machine
423 * framework and executed by only one CPU while all other CPUs will spin and
424 * wait, so no locking is required in this function.
426 static void update_sections_early(struct section_perm perms[], int n)
428 struct task_struct *t, *s;
430 for_each_process(t) {
431 if (t->flags & PF_KTHREAD)
433 for_each_thread(t, s)
435 set_section_perms(perms, n, true, s->mm);
437 set_section_perms(perms, n, true, current->active_mm);
438 set_section_perms(perms, n, true, &init_mm);
441 static int __fix_kernmem_perms(void *unused)
443 update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
447 static void fix_kernmem_perms(void)
449 stop_machine(__fix_kernmem_perms, NULL, NULL);
452 static int __mark_rodata_ro(void *unused)
454 update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
458 void mark_rodata_ro(void)
460 stop_machine(__mark_rodata_ro, NULL, NULL);
465 static inline void fix_kernmem_perms(void) { }
466 #endif /* CONFIG_STRICT_KERNEL_RWX */
468 void free_initmem(void)
472 poison_init_mem(__init_begin, __init_end - __init_begin);
473 if (!machine_is_integrator() && !machine_is_cintegrator())
474 free_initmem_default(-1);
477 #ifdef CONFIG_BLK_DEV_INITRD
478 void free_initrd_mem(unsigned long start, unsigned long end)
480 if (start == initrd_start)
481 start = round_down(start, PAGE_SIZE);
482 if (end == initrd_end)
483 end = round_up(end, PAGE_SIZE);
485 poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
486 free_reserved_area((void *)start, (void *)end, -1, "initrd");