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
46 unsigned 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
54 static 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
65 static 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
75 static 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
85 phys_addr_t arm_dma_zone_size __read_mostly;
86 EXPORT_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 */
94 phys_addr_t arm_dma_limit;
95 unsigned long arm_dma_pfn_limit;
96 #endif
97
98 void __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
110 static 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
126 int 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 }
146 EXPORT_SYMBOL(pfn_valid);
147 #endif
148
149 static bool arm_memblock_steal_permitted = true;
150
151 phys_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("Failed to steal %pa bytes at %pS\n",
160 &size, (void *)_RET_IP_);
161
162 memblock_phys_free(phys, size);
163 memblock_remove(phys, size);
164
165 return phys;
166 }
167
168 #ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND
169 void 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
184 void __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(arm_dma_limit);
201
202 arm_memblock_steal_permitted = false;
203 memblock_dump_all();
204 }
205
206 void __init bootmem_init(void)
207 {
208 memblock_allow_resize();
209
210 find_limits(&min_low_pfn, &max_low_pfn, &max_pfn);
211
212 early_memtest((phys_addr_t)min_low_pfn << PAGE_SHIFT,
213 (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_low_pfn, max_low_pfn, max_pfn);
227 }
228
229 /*
230 * Poison init memory with an undefined instruction (ARM) or a branch to an
231 * undefined instruction (Thumb).
232 */
233 static 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
240 static void __init free_highpages(void)
241 {
242 #ifdef CONFIG_HIGHMEM
243 unsigned long max_low = max_low_pfn;
244 phys_addr_t range_start, range_end;
245 u64 i;
246
247 /* set highmem page free */
248 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
249 &range_start, &range_end, NULL) {
250 unsigned long start = PFN_UP(range_start);
251 unsigned long end = PFN_DOWN(range_end);
252
253 /* Ignore complete lowmem entries */
254 if (end <= max_low)
255 continue;
256
257 /* Truncate partial highmem entries */
258 if (start < max_low)
259 start = max_low;
260
261 for (; start < end; start++)
262 free_highmem_page(pfn_to_page(start));
263 }
264 #endif
265 }
266
267 /*
268 * mem_init() marks the free areas in the mem_map and tells us how much
269 * memory is free. This is done after various parts of the system have
270 * claimed their memory after the kernel image.
271 */
272 void __init mem_init(void)
273 {
274 #ifdef CONFIG_ARM_LPAE
275 swiotlb_init(max_pfn > arm_dma_pfn_limit, SWIOTLB_VERBOSE);
276 #endif
277
278 set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
279
280 /* this will put all unused low memory onto the freelists */
281 memblock_free_all();
282
283 #ifdef CONFIG_SA1111
284 /* now that our DMA memory is actually so designated, we can free it */
285 free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
286 #endif
287
288 free_highpages();
289
290 /*
291 * Check boundaries twice: Some fundamental inconsistencies can
292 * be detected at build time already.
293 */
294 #ifdef CONFIG_MMU
295 BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR);
296 BUG_ON(TASK_SIZE > MODULES_VADDR);
297 #endif
298
299 #ifdef CONFIG_HIGHMEM
300 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
301 BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
302 #endif
303 }
304
305 #ifdef CONFIG_STRICT_KERNEL_RWX
306 struct section_perm {
307 const char *name;
308 unsigned long start;
309 unsigned long end;
310 pmdval_t mask;
311 pmdval_t prot;
312 pmdval_t clear;
313 };
314
315 /* First section-aligned location at or after __start_rodata. */
316 extern char __start_rodata_section_aligned[];
317
318 static struct section_perm nx_perms[] = {
319 /* Make pages tables, etc before _stext RW (set NX). */
320 {
321 .name = "pre-text NX",
322 .start = PAGE_OFFSET,
323 .end = (unsigned long)_stext,
324 .mask = ~PMD_SECT_XN,
325 .prot = PMD_SECT_XN,
326 },
327 /* Make init RW (set NX). */
328 {
329 .name = "init NX",
330 .start = (unsigned long)__init_begin,
331 .end = (unsigned long)_sdata,
332 .mask = ~PMD_SECT_XN,
333 .prot = PMD_SECT_XN,
334 },
335 /* Make rodata NX (set RO in ro_perms below). */
336 {
337 .name = "rodata NX",
338 .start = (unsigned long)__start_rodata_section_aligned,
339 .end = (unsigned long)__init_begin,
340 .mask = ~PMD_SECT_XN,
341 .prot = PMD_SECT_XN,
342 },
343 };
344
345 static struct section_perm ro_perms[] = {
346 /* Make kernel code and rodata RX (set RO). */
347 {
348 .name = "text/rodata RO",
349 .start = (unsigned long)_stext,
350 .end = (unsigned long)__init_begin,
351 #ifdef CONFIG_ARM_LPAE
352 .mask = ~(L_PMD_SECT_RDONLY | PMD_SECT_AP2),
353 .prot = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
354 #else
355 .mask = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
356 .prot = PMD_SECT_APX | PMD_SECT_AP_WRITE,
357 .clear = PMD_SECT_AP_WRITE,
358 #endif
359 },
360 };
361
362 /*
363 * Updates section permissions only for the current mm (sections are
364 * copied into each mm). During startup, this is the init_mm. Is only
365 * safe to be called with preemption disabled, as under stop_machine().
366 */
367 static inline void section_update(unsigned long addr, pmdval_t mask,
368 pmdval_t prot, struct mm_struct *mm)
369 {
370 pmd_t *pmd;
371
372 pmd = pmd_offset(pud_offset(p4d_offset(pgd_offset(mm, addr), addr), addr), addr);
373
374 #ifdef CONFIG_ARM_LPAE
375 pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
376 #else
377 if (addr & SECTION_SIZE)
378 pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
379 else
380 pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
381 #endif
382 flush_pmd_entry(pmd);
383 local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
384 }
385
386 /* Make sure extended page tables are in use. */
387 static inline bool arch_has_strict_perms(void)
388 {
389 if (cpu_architecture() < CPU_ARCH_ARMv6)
390 return false;
391
392 return !!(get_cr() & CR_XP);
393 }
394
395 static void set_section_perms(struct section_perm *perms, int n, bool set,
396 struct mm_struct *mm)
397 {
398 size_t i;
399 unsigned long addr;
400
401 if (!arch_has_strict_perms())
402 return;
403
404 for (i = 0; i < n; i++) {
405 if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
406 !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
407 pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
408 perms[i].name, perms[i].start, perms[i].end,
409 SECTION_SIZE);
410 continue;
411 }
412
413 for (addr = perms[i].start;
414 addr < perms[i].end;
415 addr += SECTION_SIZE)
416 section_update(addr, perms[i].mask,
417 set ? perms[i].prot : perms[i].clear, mm);
418 }
419
420 }
421
422 /*
423 * update_sections_early intended to be called only through stop_machine
424 * framework and executed by only one CPU while all other CPUs will spin and
425 * wait, so no locking is required in this function.
426 */
427 static void update_sections_early(struct section_perm perms[], int n)
428 {
429 struct task_struct *t, *s;
430
431 for_each_process(t) {
432 if (t->flags & PF_KTHREAD)
433 continue;
434 for_each_thread(t, s)
435 if (s->mm)
436 set_section_perms(perms, n, true, s->mm);
437 }
438 set_section_perms(perms, n, true, current->active_mm);
439 set_section_perms(perms, n, true, &init_mm);
440 }
441
442 static int __fix_kernmem_perms(void *unused)
443 {
444 update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
445 return 0;
446 }
447
448 static void fix_kernmem_perms(void)
449 {
450 stop_machine(__fix_kernmem_perms, NULL, NULL);
451 }
452
453 static int __mark_rodata_ro(void *unused)
454 {
455 update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
456 return 0;
457 }
458
459 void mark_rodata_ro(void)
460 {
461 stop_machine(__mark_rodata_ro, NULL, NULL);
462 arm_debug_checkwx();
463 }
464
465 #else
466 static inline void fix_kernmem_perms(void) { }
467 #endif /* CONFIG_STRICT_KERNEL_RWX */
468
469 void free_initmem(void)
470 {
471 fix_kernmem_perms();
472
473 poison_init_mem(__init_begin, __init_end - __init_begin);
474 if (!machine_is_integrator() && !machine_is_cintegrator())
475 free_initmem_default(-1);
476 }
477
478 #ifdef CONFIG_BLK_DEV_INITRD
479 void free_initrd_mem(unsigned long start, unsigned long end)
480 {
481 if (start == initrd_start)
482 start = round_down(start, PAGE_SIZE);
483 if (end == initrd_end)
484 end = round_up(end, PAGE_SIZE);
485
486 poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
487 free_reserved_area((void *)start, (void *)end, -1, "initrd");
488 }
489 #endif
490
491 #ifdef CONFIG_EXECMEM
492
493 #ifdef CONFIG_XIP_KERNEL
494 /*
495 * The XIP kernel text is mapped in the module area for modules and
496 * some other stuff to work without any indirect relocations.
497 * MODULES_VADDR is redefined here and not in asm/memory.h to avoid
498 * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off.
499 */
500 #undef MODULES_VADDR
501 #define MODULES_VADDR (((unsigned long)_exiprom + ~PMD_MASK) & PMD_MASK)
502 #endif
503
504 #ifdef CONFIG_MMU
505 static struct execmem_info execmem_info __ro_after_init;
506
507 struct execmem_info __init *execmem_arch_setup(void)
508 {
509 unsigned long fallback_start = 0, fallback_end = 0;
510
511 if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS)) {
512 fallback_start = VMALLOC_START;
513 fallback_end = VMALLOC_END;
514 }
515
516 execmem_info = (struct execmem_info){
517 .ranges = {
518 [EXECMEM_DEFAULT] = {
519 .start = MODULES_VADDR,
520 .end = MODULES_END,
521 .pgprot = PAGE_KERNEL_EXEC,
522 .alignment = 1,
523 .fallback_start = fallback_start,
524 .fallback_end = fallback_end,
525 },
526 },
527 };
528
529 return &execmem_info;
530 }
531 #endif /* CONFIG_MMU */
532
533 #endif /* CONFIG_EXECMEM */
534
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