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);
129 if (__phys_to_pfn(addr) != pfn)
132 return memblock_is_map_memory(addr);
134 EXPORT_SYMBOL(pfn_valid);
137 static bool arm_memblock_steal_permitted = true;
139 phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
143 BUG_ON(!arm_memblock_steal_permitted);
145 phys = memblock_phys_alloc(size, align);
147 panic("Failed to steal %pa bytes at %pS\n",
148 &size, (void *)_RET_IP_);
150 memblock_free(phys, size);
151 memblock_remove(phys, size);
156 static void __init arm_initrd_init(void)
158 #ifdef CONFIG_BLK_DEV_INITRD
162 initrd_start = initrd_end = 0;
164 if (!phys_initrd_size)
168 * Round the memory region to page boundaries as per free_initrd_mem()
169 * This allows us to detect whether the pages overlapping the initrd
170 * are in use, but more importantly, reserves the entire set of pages
171 * as we don't want these pages allocated for other purposes.
173 start = round_down(phys_initrd_start, PAGE_SIZE);
174 size = phys_initrd_size + (phys_initrd_start - start);
175 size = round_up(size, PAGE_SIZE);
177 if (!memblock_is_region_memory(start, size)) {
178 pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",
183 if (memblock_is_region_reserved(start, size)) {
184 pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
189 memblock_reserve(start, size);
191 /* Now convert initrd to virtual addresses */
192 initrd_start = __phys_to_virt(phys_initrd_start);
193 initrd_end = initrd_start + phys_initrd_size;
197 #ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND
198 void check_cpu_icache_size(int cpuid)
202 asm("mrc p15, 0, %0, c0, c0, 1" : "=r" (ctr));
204 size = 1 << ((ctr & 0xf) + 2);
205 if (cpuid != 0 && icache_size != size)
206 pr_info("CPU%u: detected I-Cache line size mismatch, workaround enabled\n",
208 if (icache_size > size)
213 void __init arm_memblock_init(const struct machine_desc *mdesc)
215 /* Register the kernel text, kernel data and initrd with memblock. */
216 memblock_reserve(__pa(KERNEL_START), KERNEL_END - KERNEL_START);
220 arm_mm_memblock_reserve();
222 /* reserve any platform specific memblock areas */
226 early_init_fdt_reserve_self();
227 early_init_fdt_scan_reserved_mem();
229 /* reserve memory for DMA contiguous allocations */
230 dma_contiguous_reserve(arm_dma_limit);
232 arm_memblock_steal_permitted = false;
236 void __init bootmem_init(void)
238 memblock_allow_resize();
240 find_limits(&min_low_pfn, &max_low_pfn, &max_pfn);
242 early_memtest((phys_addr_t)min_low_pfn << PAGE_SHIFT,
243 (phys_addr_t)max_low_pfn << PAGE_SHIFT);
246 * sparse_init() tries to allocate memory from memblock, so must be
247 * done after the fixed reservations
252 * Now free the memory - free_area_init needs
253 * the sparse mem_map arrays initialized by sparse_init()
254 * for memmap_init_zone(), otherwise all PFNs are invalid.
256 zone_sizes_init(min_low_pfn, max_low_pfn, max_pfn);
260 * Poison init memory with an undefined instruction (ARM) or a branch to an
261 * undefined instruction (Thumb).
263 static inline void poison_init_mem(void *s, size_t count)
266 for (; count != 0; count -= 4)
270 static void __init free_highpages(void)
272 #ifdef CONFIG_HIGHMEM
273 unsigned long max_low = max_low_pfn;
274 phys_addr_t range_start, range_end;
277 /* set highmem page free */
278 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
279 &range_start, &range_end, NULL) {
280 unsigned long start = PFN_UP(range_start);
281 unsigned long end = PFN_DOWN(range_end);
283 /* Ignore complete lowmem entries */
287 /* Truncate partial highmem entries */
291 for (; start < end; start++)
292 free_highmem_page(pfn_to_page(start));
298 * mem_init() marks the free areas in the mem_map and tells us how much
299 * memory is free. This is done after various parts of the system have
300 * claimed their memory after the kernel image.
302 void __init mem_init(void)
304 #ifdef CONFIG_ARM_LPAE
308 set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
310 /* this will put all unused low memory onto the freelists */
314 /* now that our DMA memory is actually so designated, we can free it */
315 free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
320 mem_init_print_info(NULL);
323 * Check boundaries twice: Some fundamental inconsistencies can
324 * be detected at build time already.
327 BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR);
328 BUG_ON(TASK_SIZE > MODULES_VADDR);
331 #ifdef CONFIG_HIGHMEM
332 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
333 BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
337 #ifdef CONFIG_STRICT_KERNEL_RWX
338 struct section_perm {
347 /* First section-aligned location at or after __start_rodata. */
348 extern char __start_rodata_section_aligned[];
350 static struct section_perm nx_perms[] = {
351 /* Make pages tables, etc before _stext RW (set NX). */
353 .name = "pre-text NX",
354 .start = PAGE_OFFSET,
355 .end = (unsigned long)_stext,
356 .mask = ~PMD_SECT_XN,
359 /* Make init RW (set NX). */
362 .start = (unsigned long)__init_begin,
363 .end = (unsigned long)_sdata,
364 .mask = ~PMD_SECT_XN,
367 /* Make rodata NX (set RO in ro_perms below). */
370 .start = (unsigned long)__start_rodata_section_aligned,
371 .end = (unsigned long)__init_begin,
372 .mask = ~PMD_SECT_XN,
377 static struct section_perm ro_perms[] = {
378 /* Make kernel code and rodata RX (set RO). */
380 .name = "text/rodata RO",
381 .start = (unsigned long)_stext,
382 .end = (unsigned long)__init_begin,
383 #ifdef CONFIG_ARM_LPAE
384 .mask = ~(L_PMD_SECT_RDONLY | PMD_SECT_AP2),
385 .prot = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
387 .mask = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
388 .prot = PMD_SECT_APX | PMD_SECT_AP_WRITE,
389 .clear = PMD_SECT_AP_WRITE,
395 * Updates section permissions only for the current mm (sections are
396 * copied into each mm). During startup, this is the init_mm. Is only
397 * safe to be called with preemption disabled, as under stop_machine().
399 static inline void section_update(unsigned long addr, pmdval_t mask,
400 pmdval_t prot, struct mm_struct *mm)
404 pmd = pmd_offset(pud_offset(p4d_offset(pgd_offset(mm, addr), addr), addr), addr);
406 #ifdef CONFIG_ARM_LPAE
407 pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
409 if (addr & SECTION_SIZE)
410 pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
412 pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
414 flush_pmd_entry(pmd);
415 local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
418 /* Make sure extended page tables are in use. */
419 static inline bool arch_has_strict_perms(void)
421 if (cpu_architecture() < CPU_ARCH_ARMv6)
424 return !!(get_cr() & CR_XP);
427 static void set_section_perms(struct section_perm *perms, int n, bool set,
428 struct mm_struct *mm)
433 if (!arch_has_strict_perms())
436 for (i = 0; i < n; i++) {
437 if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
438 !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
439 pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
440 perms[i].name, perms[i].start, perms[i].end,
445 for (addr = perms[i].start;
447 addr += SECTION_SIZE)
448 section_update(addr, perms[i].mask,
449 set ? perms[i].prot : perms[i].clear, mm);
455 * update_sections_early intended to be called only through stop_machine
456 * framework and executed by only one CPU while all other CPUs will spin and
457 * wait, so no locking is required in this function.
459 static void update_sections_early(struct section_perm perms[], int n)
461 struct task_struct *t, *s;
463 for_each_process(t) {
464 if (t->flags & PF_KTHREAD)
466 for_each_thread(t, s)
468 set_section_perms(perms, n, true, s->mm);
470 set_section_perms(perms, n, true, current->active_mm);
471 set_section_perms(perms, n, true, &init_mm);
474 static int __fix_kernmem_perms(void *unused)
476 update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
480 static void fix_kernmem_perms(void)
482 stop_machine(__fix_kernmem_perms, NULL, NULL);
485 static int __mark_rodata_ro(void *unused)
487 update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
491 static int kernel_set_to_readonly __read_mostly;
493 void mark_rodata_ro(void)
495 kernel_set_to_readonly = 1;
496 stop_machine(__mark_rodata_ro, NULL, NULL);
500 void set_kernel_text_rw(void)
502 if (!kernel_set_to_readonly)
505 set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), false,
509 void set_kernel_text_ro(void)
511 if (!kernel_set_to_readonly)
514 set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), true,
519 static inline void fix_kernmem_perms(void) { }
520 #endif /* CONFIG_STRICT_KERNEL_RWX */
522 void free_initmem(void)
526 poison_init_mem(__init_begin, __init_end - __init_begin);
527 if (!machine_is_integrator() && !machine_is_cintegrator())
528 free_initmem_default(-1);
531 #ifdef CONFIG_BLK_DEV_INITRD
532 void free_initrd_mem(unsigned long start, unsigned long end)
534 if (start == initrd_start)
535 start = round_down(start, PAGE_SIZE);
536 if (end == initrd_end)
537 end = round_up(end, PAGE_SIZE);
539 poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
540 free_reserved_area((void *)start, (void *)end, -1, "initrd");