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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/arch/arm/mm/init.c
4 *
5 * Copyright (C) 1995-2005 Russell King
6 */
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>
25#include <linux/execmem.h>
26
27#include <asm/cp15.h>
28#include <asm/mach-types.h>
29#include <asm/memblock.h>
30#include <asm/page.h>
31#include <asm/prom.h>
32#include <asm/sections.h>
33#include <asm/setup.h>
34#include <asm/set_memory.h>
35#include <asm/system_info.h>
36#include <asm/tlb.h>
37#include <asm/fixmap.h>
38#include <asm/ptdump.h>
39
40#include <asm/mach/arch.h>
41#include <asm/mach/map.h>
42
43#include "mm.h"
44
45#ifdef CONFIG_CPU_CP15_MMU
46unsigned long __init __clear_cr(unsigned long mask)
47{
48 cr_alignment = cr_alignment & ~mask;
49 return cr_alignment;
50}
51#endif
52
53#ifdef CONFIG_BLK_DEV_INITRD
54static int __init parse_tag_initrd(const struct tag *tag)
55{
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;
60 return 0;
61}
62
63__tagtable(ATAG_INITRD, parse_tag_initrd);
64
65static int __init parse_tag_initrd2(const struct tag *tag)
66{
67 phys_initrd_start = tag->u.initrd.start;
68 phys_initrd_size = tag->u.initrd.size;
69 return 0;
70}
71
72__tagtable(ATAG_INITRD2, parse_tag_initrd2);
73#endif
74
75static void __init find_limits(unsigned long *min, unsigned long *max_low,
76 unsigned long *max_high)
77{
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());
81}
82
83#ifdef CONFIG_ZONE_DMA
84
85phys_addr_t arm_dma_zone_size __read_mostly;
86EXPORT_SYMBOL(arm_dma_zone_size);
87
88/*
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.
93 */
94phys_addr_t arm_dma_limit;
95unsigned long arm_dma_pfn_limit;
96#endif
97
98void __init setup_dma_zone(const struct machine_desc *mdesc)
99{
100#ifdef CONFIG_ZONE_DMA
101 if (mdesc->dma_zone_size) {
102 arm_dma_zone_size = mdesc->dma_zone_size;
103 arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
104 } else
105 arm_dma_limit = 0xffffffff;
106 arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT;
107#endif
108}
109
110static void __init zone_sizes_init(unsigned long min, unsigned long max_low,
111 unsigned long max_high)
112{
113 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
114
115#ifdef CONFIG_ZONE_DMA
116 max_zone_pfn[ZONE_DMA] = min(arm_dma_pfn_limit, max_low);
117#endif
118 max_zone_pfn[ZONE_NORMAL] = max_low;
119#ifdef CONFIG_HIGHMEM
120 max_zone_pfn[ZONE_HIGHMEM] = max_high;
121#endif
122 free_area_init(max_zone_pfn);
123}
124
125#ifdef CONFIG_HAVE_ARCH_PFN_VALID
126int pfn_valid(unsigned long pfn)
127{
128 phys_addr_t addr = __pfn_to_phys(pfn);
129 unsigned long pageblock_size = PAGE_SIZE * pageblock_nr_pages;
130
131 if (__phys_to_pfn(addr) != pfn)
132 return 0;
133
134 /*
135 * If address less than pageblock_size bytes away from a present
136 * memory chunk there still will be a memory map entry for it
137 * because we round freed memory map to the pageblock boundaries.
138 */
139 if (memblock_overlaps_region(&memblock.memory,
140 ALIGN_DOWN(addr, pageblock_size),
141 pageblock_size))
142 return 1;
143
144 return 0;
145}
146EXPORT_SYMBOL(pfn_valid);
147#endif
148
149static bool arm_memblock_steal_permitted = true;
150
151phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
152{
153 phys_addr_t phys;
154
155 BUG_ON(!arm_memblock_steal_permitted);
156
157 phys = memblock_phys_alloc(size, align);
158 if (!phys)
159 panic(fmt: "Failed to steal %pa bytes at %pS\n",
160 &size, (void *)_RET_IP_);
161
162 memblock_phys_free(base: phys, size);
163 memblock_remove(base: phys, size);
164
165 return phys;
166}
167
168#ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND
169void check_cpu_icache_size(int cpuid)
170{
171 u32 size, ctr;
172
173 asm("mrc p15, 0, %0, c0, c0, 1" : "=r" (ctr));
174
175 size = 1 << ((ctr & 0xf) + 2);
176 if (cpuid != 0 && icache_size != size)
177 pr_info("CPU%u: detected I-Cache line size mismatch, workaround enabled\n",
178 cpuid);
179 if (icache_size > size)
180 icache_size = size;
181}
182#endif
183
184void __init arm_memblock_init(const struct machine_desc *mdesc)
185{
186 /* Register the kernel text, kernel data and initrd with memblock. */
187 memblock_reserve(__pa(KERNEL_START), KERNEL_END - KERNEL_START);
188
189 reserve_initrd_mem();
190
191 arm_mm_memblock_reserve();
192
193 /* reserve any platform specific memblock areas */
194 if (mdesc->reserve)
195 mdesc->reserve();
196
197 early_init_fdt_scan_reserved_mem();
198
199 /* reserve memory for DMA contiguous allocations */
200 dma_contiguous_reserve(addr_limit: arm_dma_limit);
201
202 arm_memblock_steal_permitted = false;
203 memblock_dump_all();
204}
205
206void __init bootmem_init(void)
207{
208 memblock_allow_resize();
209
210 find_limits(min: &min_low_pfn, max_low: &max_low_pfn, max_high: &max_pfn);
211
212 early_memtest(start: (phys_addr_t)min_low_pfn << PAGE_SHIFT,
213 end: (phys_addr_t)max_low_pfn << PAGE_SHIFT);
214
215 /*
216 * sparse_init() tries to allocate memory from memblock, so must be
217 * done after the fixed reservations
218 */
219 sparse_init();
220
221 /*
222 * Now free the memory - free_area_init needs
223 * the sparse mem_map arrays initialized by sparse_init()
224 * for memmap_init_zone(), otherwise all PFNs are invalid.
225 */
226 zone_sizes_init(min: min_low_pfn, max_low: max_low_pfn, max_high: max_pfn);
227}
228
229/*
230 * Poison init memory with an undefined instruction (ARM) or a branch to an
231 * undefined instruction (Thumb).
232 */
233static inline void poison_init_mem(void *s, size_t count)
234{
235 u32 *p = (u32 *)s;
236 for (; count != 0; count -= 4)
237 *p++ = 0xe7fddef0;
238}
239
240void __init arch_mm_preinit(void)
241{
242#ifdef CONFIG_ARM_LPAE
243 swiotlb_init(max_pfn > arm_dma_pfn_limit, SWIOTLB_VERBOSE);
244#endif
245
246#ifdef CONFIG_SA1111
247 /* now that our DMA memory is actually so designated, we can free it */
248 memblock_phys_free(PHYS_OFFSET, __pa(swapper_pg_dir) - PHYS_OFFSET);
249#endif
250
251 /*
252 * Check boundaries twice: Some fundamental inconsistencies can
253 * be detected at build time already.
254 */
255#ifdef CONFIG_MMU
256 BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR);
257 BUG_ON(TASK_SIZE > MODULES_VADDR);
258#endif
259
260#ifdef CONFIG_HIGHMEM
261 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
262 BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
263#endif
264}
265
266#ifdef CONFIG_STRICT_KERNEL_RWX
267struct section_perm {
268 const char *name;
269 unsigned long start;
270 unsigned long end;
271 pmdval_t mask;
272 pmdval_t prot;
273 pmdval_t clear;
274};
275
276/* First section-aligned location at or after __start_rodata. */
277extern char __start_rodata_section_aligned[];
278
279static struct section_perm nx_perms[] = {
280 /* Make pages tables, etc before _stext RW (set NX). */
281 {
282 .name = "pre-text NX",
283 .start = PAGE_OFFSET,
284 .end = (unsigned long)_stext,
285 .mask = ~PMD_SECT_XN,
286 .prot = PMD_SECT_XN,
287 },
288 /* Make init RW (set NX). */
289 {
290 .name = "init NX",
291 .start = (unsigned long)__init_begin,
292 .end = (unsigned long)_sdata,
293 .mask = ~PMD_SECT_XN,
294 .prot = PMD_SECT_XN,
295 },
296 /* Make rodata NX (set RO in ro_perms below). */
297 {
298 .name = "rodata NX",
299 .start = (unsigned long)__start_rodata_section_aligned,
300 .end = (unsigned long)__init_begin,
301 .mask = ~PMD_SECT_XN,
302 .prot = PMD_SECT_XN,
303 },
304};
305
306static struct section_perm ro_perms[] = {
307 /* Make kernel code and rodata RX (set RO). */
308 {
309 .name = "text/rodata RO",
310 .start = (unsigned long)_stext,
311 .end = (unsigned long)__init_begin,
312#ifdef CONFIG_ARM_LPAE
313 .mask = ~(L_PMD_SECT_RDONLY | PMD_SECT_AP2),
314 .prot = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
315#else
316 .mask = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
317 .prot = PMD_SECT_APX | PMD_SECT_AP_WRITE,
318 .clear = PMD_SECT_AP_WRITE,
319#endif
320 },
321};
322
323/*
324 * Updates section permissions only for the current mm (sections are
325 * copied into each mm). During startup, this is the init_mm. Is only
326 * safe to be called with preemption disabled, as under stop_machine().
327 */
328static inline void section_update(unsigned long addr, pmdval_t mask,
329 pmdval_t prot, struct mm_struct *mm)
330{
331 pmd_t *pmd;
332
333 pmd = pmd_offset(pud_offset(p4d: p4d_offset(pgd_offset(mm, addr), address: addr), address: addr), address: addr);
334
335#ifdef CONFIG_ARM_LPAE
336 pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
337#else
338 if (addr & SECTION_SIZE)
339 pmd[1] = __pmd(val: (pmd_val(pmd: pmd[1]) & mask) | prot);
340 else
341 pmd[0] = __pmd(val: (pmd_val(pmd: pmd[0]) & mask) | prot);
342#endif
343 flush_pmd_entry(pmd);
344 local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
345}
346
347/* Make sure extended page tables are in use. */
348static inline bool arch_has_strict_perms(void)
349{
350 if (cpu_architecture() < CPU_ARCH_ARMv6)
351 return false;
352
353 return !!(get_cr() & CR_XP);
354}
355
356static void set_section_perms(struct section_perm *perms, int n, bool set,
357 struct mm_struct *mm)
358{
359 size_t i;
360 unsigned long addr;
361
362 if (!arch_has_strict_perms())
363 return;
364
365 for (i = 0; i < n; i++) {
366 if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
367 !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
368 pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
369 perms[i].name, perms[i].start, perms[i].end,
370 SECTION_SIZE);
371 continue;
372 }
373
374 for (addr = perms[i].start;
375 addr < perms[i].end;
376 addr += SECTION_SIZE)
377 section_update(addr, mask: perms[i].mask,
378 prot: set ? perms[i].prot : perms[i].clear, mm);
379 }
380
381}
382
383/*
384 * update_sections_early intended to be called only through stop_machine
385 * framework and executed by only one CPU while all other CPUs will spin and
386 * wait, so no locking is required in this function.
387 */
388static void update_sections_early(struct section_perm perms[], int n)
389{
390 struct task_struct *t, *s;
391
392 for_each_process(t) {
393 if (t->flags & PF_KTHREAD)
394 continue;
395 for_each_thread(t, s)
396 if (s->mm)
397 set_section_perms(perms, n, set: true, mm: s->mm);
398 }
399 set_section_perms(perms, n, set: true, current->active_mm);
400 set_section_perms(perms, n, set: true, mm: &init_mm);
401}
402
403static int __fix_kernmem_perms(void *unused)
404{
405 update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
406 return 0;
407}
408
409static void fix_kernmem_perms(void)
410{
411 stop_machine(fn: __fix_kernmem_perms, NULL, NULL);
412}
413
414static int __mark_rodata_ro(void *unused)
415{
416 update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
417 return 0;
418}
419
420void mark_rodata_ro(void)
421{
422 stop_machine(fn: __mark_rodata_ro, NULL, NULL);
423 arm_debug_checkwx();
424}
425
426#else
427static inline void fix_kernmem_perms(void) { }
428#endif /* CONFIG_STRICT_KERNEL_RWX */
429
430void free_initmem(void)
431{
432 fix_kernmem_perms();
433
434 poison_init_mem(s: __init_begin, count: __init_end - __init_begin);
435 if (!machine_is_integrator() && !machine_is_cintegrator())
436 free_initmem_default(poison: -1);
437}
438
439#ifdef CONFIG_BLK_DEV_INITRD
440void free_initrd_mem(unsigned long start, unsigned long end)
441{
442 if (start == initrd_start)
443 start = round_down(start, PAGE_SIZE);
444 if (end == initrd_end)
445 end = round_up(end, PAGE_SIZE);
446
447 poison_init_mem(s: (void *)start, PAGE_ALIGN(end) - start);
448 free_reserved_area(start: (void *)start, end: (void *)end, poison: -1, s: "initrd");
449}
450#endif
451
452#ifdef CONFIG_EXECMEM
453
454#ifdef CONFIG_XIP_KERNEL
455/*
456 * The XIP kernel text is mapped in the module area for modules and
457 * some other stuff to work without any indirect relocations.
458 * MODULES_VADDR is redefined here and not in asm/memory.h to avoid
459 * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off.
460 */
461#undef MODULES_VADDR
462#define MODULES_VADDR (((unsigned long)_exiprom + ~PMD_MASK) & PMD_MASK)
463#endif
464
465#ifdef CONFIG_MMU
466static struct execmem_info execmem_info __ro_after_init;
467
468struct execmem_info __init *execmem_arch_setup(void)
469{
470 unsigned long fallback_start = 0, fallback_end = 0;
471
472 if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS)) {
473 fallback_start = VMALLOC_START;
474 fallback_end = VMALLOC_END;
475 }
476
477 execmem_info = (struct execmem_info){
478 .ranges = {
479 [EXECMEM_DEFAULT] = {
480 .start = MODULES_VADDR,
481 .end = MODULES_END,
482 .pgprot = PAGE_KERNEL_EXEC,
483 .alignment = 1,
484 .fallback_start = fallback_start,
485 .fallback_end = fallback_end,
486 },
487 },
488 };
489
490 return &execmem_info;
491}
492#endif /* CONFIG_MMU */
493
494#endif /* CONFIG_EXECMEM */
495

source code of linux/arch/arm/mm/init.c