xref: /openbmc/linux/arch/arm/mm/init.c (revision 08193d1a)
1 /*
2  *  linux/arch/arm/mm/init.c
3  *
4  *  Copyright (C) 1995-2005 Russell King
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
10 #include <linux/kernel.h>
11 #include <linux/errno.h>
12 #include <linux/swap.h>
13 #include <linux/init.h>
14 #include <linux/bootmem.h>
15 #include <linux/mman.h>
16 #include <linux/sched/signal.h>
17 #include <linux/sched/task.h>
18 #include <linux/export.h>
19 #include <linux/nodemask.h>
20 #include <linux/initrd.h>
21 #include <linux/of_fdt.h>
22 #include <linux/highmem.h>
23 #include <linux/gfp.h>
24 #include <linux/memblock.h>
25 #include <linux/dma-contiguous.h>
26 #include <linux/sizes.h>
27 #include <linux/stop_machine.h>
28 
29 #include <asm/cp15.h>
30 #include <asm/mach-types.h>
31 #include <asm/memblock.h>
32 #include <asm/memory.h>
33 #include <asm/prom.h>
34 #include <asm/sections.h>
35 #include <asm/setup.h>
36 #include <asm/system_info.h>
37 #include <asm/tlb.h>
38 #include <asm/fixmap.h>
39 #include <asm/ptdump.h>
40 
41 #include <asm/mach/arch.h>
42 #include <asm/mach/map.h>
43 
44 #include "mm.h"
45 
46 #ifdef CONFIG_CPU_CP15_MMU
47 unsigned long __init __clear_cr(unsigned long mask)
48 {
49 	cr_alignment = cr_alignment & ~mask;
50 	return cr_alignment;
51 }
52 #endif
53 
54 static phys_addr_t phys_initrd_start __initdata = 0;
55 static unsigned long phys_initrd_size __initdata = 0;
56 
57 static int __init early_initrd(char *p)
58 {
59 	phys_addr_t start;
60 	unsigned long size;
61 	char *endp;
62 
63 	start = memparse(p, &endp);
64 	if (*endp == ',') {
65 		size = memparse(endp + 1, NULL);
66 
67 		phys_initrd_start = start;
68 		phys_initrd_size = size;
69 	}
70 	return 0;
71 }
72 early_param("initrd", early_initrd);
73 
74 static int __init parse_tag_initrd(const struct tag *tag)
75 {
76 	pr_warn("ATAG_INITRD is deprecated; "
77 		"please update your bootloader.\n");
78 	phys_initrd_start = __virt_to_phys(tag->u.initrd.start);
79 	phys_initrd_size = tag->u.initrd.size;
80 	return 0;
81 }
82 
83 __tagtable(ATAG_INITRD, parse_tag_initrd);
84 
85 static int __init parse_tag_initrd2(const struct tag *tag)
86 {
87 	phys_initrd_start = tag->u.initrd.start;
88 	phys_initrd_size = tag->u.initrd.size;
89 	return 0;
90 }
91 
92 __tagtable(ATAG_INITRD2, parse_tag_initrd2);
93 
94 static void __init find_limits(unsigned long *min, unsigned long *max_low,
95 			       unsigned long *max_high)
96 {
97 	*max_low = PFN_DOWN(memblock_get_current_limit());
98 	*min = PFN_UP(memblock_start_of_DRAM());
99 	*max_high = PFN_DOWN(memblock_end_of_DRAM());
100 }
101 
102 #ifdef CONFIG_ZONE_DMA
103 
104 phys_addr_t arm_dma_zone_size __read_mostly;
105 EXPORT_SYMBOL(arm_dma_zone_size);
106 
107 /*
108  * The DMA mask corresponding to the maximum bus address allocatable
109  * using GFP_DMA.  The default here places no restriction on DMA
110  * allocations.  This must be the smallest DMA mask in the system,
111  * so a successful GFP_DMA allocation will always satisfy this.
112  */
113 phys_addr_t arm_dma_limit;
114 unsigned long arm_dma_pfn_limit;
115 
116 static void __init arm_adjust_dma_zone(unsigned long *size, unsigned long *hole,
117 	unsigned long dma_size)
118 {
119 	if (size[0] <= dma_size)
120 		return;
121 
122 	size[ZONE_NORMAL] = size[0] - dma_size;
123 	size[ZONE_DMA] = dma_size;
124 	hole[ZONE_NORMAL] = hole[0];
125 	hole[ZONE_DMA] = 0;
126 }
127 #endif
128 
129 void __init setup_dma_zone(const struct machine_desc *mdesc)
130 {
131 #ifdef CONFIG_ZONE_DMA
132 	if (mdesc->dma_zone_size) {
133 		arm_dma_zone_size = mdesc->dma_zone_size;
134 		arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
135 	} else
136 		arm_dma_limit = 0xffffffff;
137 	arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT;
138 #endif
139 }
140 
141 static void __init zone_sizes_init(unsigned long min, unsigned long max_low,
142 	unsigned long max_high)
143 {
144 	unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
145 	struct memblock_region *reg;
146 
147 	/*
148 	 * initialise the zones.
149 	 */
150 	memset(zone_size, 0, sizeof(zone_size));
151 
152 	/*
153 	 * The memory size has already been determined.  If we need
154 	 * to do anything fancy with the allocation of this memory
155 	 * to the zones, now is the time to do it.
156 	 */
157 	zone_size[0] = max_low - min;
158 #ifdef CONFIG_HIGHMEM
159 	zone_size[ZONE_HIGHMEM] = max_high - max_low;
160 #endif
161 
162 	/*
163 	 * Calculate the size of the holes.
164 	 *  holes = node_size - sum(bank_sizes)
165 	 */
166 	memcpy(zhole_size, zone_size, sizeof(zhole_size));
167 	for_each_memblock(memory, reg) {
168 		unsigned long start = memblock_region_memory_base_pfn(reg);
169 		unsigned long end = memblock_region_memory_end_pfn(reg);
170 
171 		if (start < max_low) {
172 			unsigned long low_end = min(end, max_low);
173 			zhole_size[0] -= low_end - start;
174 		}
175 #ifdef CONFIG_HIGHMEM
176 		if (end > max_low) {
177 			unsigned long high_start = max(start, max_low);
178 			zhole_size[ZONE_HIGHMEM] -= end - high_start;
179 		}
180 #endif
181 	}
182 
183 #ifdef CONFIG_ZONE_DMA
184 	/*
185 	 * Adjust the sizes according to any special requirements for
186 	 * this machine type.
187 	 */
188 	if (arm_dma_zone_size)
189 		arm_adjust_dma_zone(zone_size, zhole_size,
190 			arm_dma_zone_size >> PAGE_SHIFT);
191 #endif
192 
193 	free_area_init_node(0, zone_size, min, zhole_size);
194 }
195 
196 #ifdef CONFIG_HAVE_ARCH_PFN_VALID
197 int pfn_valid(unsigned long pfn)
198 {
199 	return memblock_is_map_memory(__pfn_to_phys(pfn));
200 }
201 EXPORT_SYMBOL(pfn_valid);
202 #endif
203 
204 #ifndef CONFIG_SPARSEMEM
205 static void __init arm_memory_present(void)
206 {
207 }
208 #else
209 static void __init arm_memory_present(void)
210 {
211 	struct memblock_region *reg;
212 
213 	for_each_memblock(memory, reg)
214 		memory_present(0, memblock_region_memory_base_pfn(reg),
215 			       memblock_region_memory_end_pfn(reg));
216 }
217 #endif
218 
219 static bool arm_memblock_steal_permitted = true;
220 
221 phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
222 {
223 	phys_addr_t phys;
224 
225 	BUG_ON(!arm_memblock_steal_permitted);
226 
227 	phys = memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ANYWHERE);
228 	memblock_free(phys, size);
229 	memblock_remove(phys, size);
230 
231 	return phys;
232 }
233 
234 static void __init arm_initrd_init(void)
235 {
236 #ifdef CONFIG_BLK_DEV_INITRD
237 	phys_addr_t start;
238 	unsigned long size;
239 
240 	/* FDT scan will populate initrd_start */
241 	if (initrd_start && !phys_initrd_size) {
242 		phys_initrd_start = __virt_to_phys(initrd_start);
243 		phys_initrd_size = initrd_end - initrd_start;
244 	}
245 
246 	initrd_start = initrd_end = 0;
247 
248 	if (!phys_initrd_size)
249 		return;
250 
251 	/*
252 	 * Round the memory region to page boundaries as per free_initrd_mem()
253 	 * This allows us to detect whether the pages overlapping the initrd
254 	 * are in use, but more importantly, reserves the entire set of pages
255 	 * as we don't want these pages allocated for other purposes.
256 	 */
257 	start = round_down(phys_initrd_start, PAGE_SIZE);
258 	size = phys_initrd_size + (phys_initrd_start - start);
259 	size = round_up(size, PAGE_SIZE);
260 
261 	if (!memblock_is_region_memory(start, size)) {
262 		pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",
263 		       (u64)start, size);
264 		return;
265 	}
266 
267 	if (memblock_is_region_reserved(start, size)) {
268 		pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
269 		       (u64)start, size);
270 		return;
271 	}
272 
273 	memblock_reserve(start, size);
274 
275 	/* Now convert initrd to virtual addresses */
276 	initrd_start = __phys_to_virt(phys_initrd_start);
277 	initrd_end = initrd_start + phys_initrd_size;
278 #endif
279 }
280 
281 void __init arm_memblock_init(const struct machine_desc *mdesc)
282 {
283 	/* Register the kernel text, kernel data and initrd with memblock. */
284 	memblock_reserve(__pa(KERNEL_START), KERNEL_END - KERNEL_START);
285 
286 	arm_initrd_init();
287 
288 	arm_mm_memblock_reserve();
289 
290 	/* reserve any platform specific memblock areas */
291 	if (mdesc->reserve)
292 		mdesc->reserve();
293 
294 	early_init_fdt_reserve_self();
295 	early_init_fdt_scan_reserved_mem();
296 
297 	/* reserve memory for DMA contiguous allocations */
298 	dma_contiguous_reserve(arm_dma_limit);
299 
300 	arm_memblock_steal_permitted = false;
301 	memblock_dump_all();
302 }
303 
304 void __init bootmem_init(void)
305 {
306 	unsigned long min, max_low, max_high;
307 
308 	memblock_allow_resize();
309 	max_low = max_high = 0;
310 
311 	find_limits(&min, &max_low, &max_high);
312 
313 	early_memtest((phys_addr_t)min << PAGE_SHIFT,
314 		      (phys_addr_t)max_low << PAGE_SHIFT);
315 
316 	/*
317 	 * Sparsemem tries to allocate bootmem in memory_present(),
318 	 * so must be done after the fixed reservations
319 	 */
320 	arm_memory_present();
321 
322 	/*
323 	 * sparse_init() needs the bootmem allocator up and running.
324 	 */
325 	sparse_init();
326 
327 	/*
328 	 * Now free the memory - free_area_init_node needs
329 	 * the sparse mem_map arrays initialized by sparse_init()
330 	 * for memmap_init_zone(), otherwise all PFNs are invalid.
331 	 */
332 	zone_sizes_init(min, max_low, max_high);
333 
334 	/*
335 	 * This doesn't seem to be used by the Linux memory manager any
336 	 * more, but is used by ll_rw_block.  If we can get rid of it, we
337 	 * also get rid of some of the stuff above as well.
338 	 */
339 	min_low_pfn = min;
340 	max_low_pfn = max_low;
341 	max_pfn = max_high;
342 }
343 
344 /*
345  * Poison init memory with an undefined instruction (ARM) or a branch to an
346  * undefined instruction (Thumb).
347  */
348 static inline void poison_init_mem(void *s, size_t count)
349 {
350 	u32 *p = (u32 *)s;
351 	for (; count != 0; count -= 4)
352 		*p++ = 0xe7fddef0;
353 }
354 
355 static inline void
356 free_memmap(unsigned long start_pfn, unsigned long end_pfn)
357 {
358 	struct page *start_pg, *end_pg;
359 	phys_addr_t pg, pgend;
360 
361 	/*
362 	 * Convert start_pfn/end_pfn to a struct page pointer.
363 	 */
364 	start_pg = pfn_to_page(start_pfn - 1) + 1;
365 	end_pg = pfn_to_page(end_pfn - 1) + 1;
366 
367 	/*
368 	 * Convert to physical addresses, and
369 	 * round start upwards and end downwards.
370 	 */
371 	pg = PAGE_ALIGN(__pa(start_pg));
372 	pgend = __pa(end_pg) & PAGE_MASK;
373 
374 	/*
375 	 * If there are free pages between these,
376 	 * free the section of the memmap array.
377 	 */
378 	if (pg < pgend)
379 		memblock_free_early(pg, pgend - pg);
380 }
381 
382 /*
383  * The mem_map array can get very big.  Free the unused area of the memory map.
384  */
385 static void __init free_unused_memmap(void)
386 {
387 	unsigned long start, prev_end = 0;
388 	struct memblock_region *reg;
389 
390 	/*
391 	 * This relies on each bank being in address order.
392 	 * The banks are sorted previously in bootmem_init().
393 	 */
394 	for_each_memblock(memory, reg) {
395 		start = memblock_region_memory_base_pfn(reg);
396 
397 #ifdef CONFIG_SPARSEMEM
398 		/*
399 		 * Take care not to free memmap entries that don't exist
400 		 * due to SPARSEMEM sections which aren't present.
401 		 */
402 		start = min(start,
403 				 ALIGN(prev_end, PAGES_PER_SECTION));
404 #else
405 		/*
406 		 * Align down here since the VM subsystem insists that the
407 		 * memmap entries are valid from the bank start aligned to
408 		 * MAX_ORDER_NR_PAGES.
409 		 */
410 		start = round_down(start, MAX_ORDER_NR_PAGES);
411 #endif
412 		/*
413 		 * If we had a previous bank, and there is a space
414 		 * between the current bank and the previous, free it.
415 		 */
416 		if (prev_end && prev_end < start)
417 			free_memmap(prev_end, start);
418 
419 		/*
420 		 * Align up here since the VM subsystem insists that the
421 		 * memmap entries are valid from the bank end aligned to
422 		 * MAX_ORDER_NR_PAGES.
423 		 */
424 		prev_end = ALIGN(memblock_region_memory_end_pfn(reg),
425 				 MAX_ORDER_NR_PAGES);
426 	}
427 
428 #ifdef CONFIG_SPARSEMEM
429 	if (!IS_ALIGNED(prev_end, PAGES_PER_SECTION))
430 		free_memmap(prev_end,
431 			    ALIGN(prev_end, PAGES_PER_SECTION));
432 #endif
433 }
434 
435 #ifdef CONFIG_HIGHMEM
436 static inline void free_area_high(unsigned long pfn, unsigned long end)
437 {
438 	for (; pfn < end; pfn++)
439 		free_highmem_page(pfn_to_page(pfn));
440 }
441 #endif
442 
443 static void __init free_highpages(void)
444 {
445 #ifdef CONFIG_HIGHMEM
446 	unsigned long max_low = max_low_pfn;
447 	struct memblock_region *mem, *res;
448 
449 	/* set highmem page free */
450 	for_each_memblock(memory, mem) {
451 		unsigned long start = memblock_region_memory_base_pfn(mem);
452 		unsigned long end = memblock_region_memory_end_pfn(mem);
453 
454 		/* Ignore complete lowmem entries */
455 		if (end <= max_low)
456 			continue;
457 
458 		if (memblock_is_nomap(mem))
459 			continue;
460 
461 		/* Truncate partial highmem entries */
462 		if (start < max_low)
463 			start = max_low;
464 
465 		/* Find and exclude any reserved regions */
466 		for_each_memblock(reserved, res) {
467 			unsigned long res_start, res_end;
468 
469 			res_start = memblock_region_reserved_base_pfn(res);
470 			res_end = memblock_region_reserved_end_pfn(res);
471 
472 			if (res_end < start)
473 				continue;
474 			if (res_start < start)
475 				res_start = start;
476 			if (res_start > end)
477 				res_start = end;
478 			if (res_end > end)
479 				res_end = end;
480 			if (res_start != start)
481 				free_area_high(start, res_start);
482 			start = res_end;
483 			if (start == end)
484 				break;
485 		}
486 
487 		/* And now free anything which remains */
488 		if (start < end)
489 			free_area_high(start, end);
490 	}
491 #endif
492 }
493 
494 /*
495  * mem_init() marks the free areas in the mem_map and tells us how much
496  * memory is free.  This is done after various parts of the system have
497  * claimed their memory after the kernel image.
498  */
499 void __init mem_init(void)
500 {
501 #ifdef CONFIG_HAVE_TCM
502 	/* These pointers are filled in on TCM detection */
503 	extern u32 dtcm_end;
504 	extern u32 itcm_end;
505 #endif
506 
507 	set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
508 
509 	/* this will put all unused low memory onto the freelists */
510 	free_unused_memmap();
511 	free_all_bootmem();
512 
513 #ifdef CONFIG_SA1111
514 	/* now that our DMA memory is actually so designated, we can free it */
515 	free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
516 #endif
517 
518 	free_highpages();
519 
520 	mem_init_print_info(NULL);
521 
522 #define MLK(b, t) b, t, ((t) - (b)) >> 10
523 #define MLM(b, t) b, t, ((t) - (b)) >> 20
524 #define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K)
525 
526 	pr_notice("Virtual kernel memory layout:\n"
527 			"    vector  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
528 #ifdef CONFIG_HAVE_TCM
529 			"    DTCM    : 0x%08lx - 0x%08lx   (%4ld kB)\n"
530 			"    ITCM    : 0x%08lx - 0x%08lx   (%4ld kB)\n"
531 #endif
532 			"    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
533 			"    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
534 			"    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
535 #ifdef CONFIG_HIGHMEM
536 			"    pkmap   : 0x%08lx - 0x%08lx   (%4ld MB)\n"
537 #endif
538 #ifdef CONFIG_MODULES
539 			"    modules : 0x%08lx - 0x%08lx   (%4ld MB)\n"
540 #endif
541 			"      .text : 0x%p" " - 0x%p" "   (%4td kB)\n"
542 			"      .init : 0x%p" " - 0x%p" "   (%4td kB)\n"
543 			"      .data : 0x%p" " - 0x%p" "   (%4td kB)\n"
544 			"       .bss : 0x%p" " - 0x%p" "   (%4td kB)\n",
545 
546 			MLK(VECTORS_BASE, VECTORS_BASE + PAGE_SIZE),
547 #ifdef CONFIG_HAVE_TCM
548 			MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
549 			MLK(ITCM_OFFSET, (unsigned long) itcm_end),
550 #endif
551 			MLK(FIXADDR_START, FIXADDR_END),
552 			MLM(VMALLOC_START, VMALLOC_END),
553 			MLM(PAGE_OFFSET, (unsigned long)high_memory),
554 #ifdef CONFIG_HIGHMEM
555 			MLM(PKMAP_BASE, (PKMAP_BASE) + (LAST_PKMAP) *
556 				(PAGE_SIZE)),
557 #endif
558 #ifdef CONFIG_MODULES
559 			MLM(MODULES_VADDR, MODULES_END),
560 #endif
561 
562 			MLK_ROUNDUP(_text, _etext),
563 			MLK_ROUNDUP(__init_begin, __init_end),
564 			MLK_ROUNDUP(_sdata, _edata),
565 			MLK_ROUNDUP(__bss_start, __bss_stop));
566 
567 #undef MLK
568 #undef MLM
569 #undef MLK_ROUNDUP
570 
571 	/*
572 	 * Check boundaries twice: Some fundamental inconsistencies can
573 	 * be detected at build time already.
574 	 */
575 #ifdef CONFIG_MMU
576 	BUILD_BUG_ON(TASK_SIZE				> MODULES_VADDR);
577 	BUG_ON(TASK_SIZE 				> MODULES_VADDR);
578 #endif
579 
580 #ifdef CONFIG_HIGHMEM
581 	BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
582 	BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE	> PAGE_OFFSET);
583 #endif
584 }
585 
586 #ifdef CONFIG_STRICT_KERNEL_RWX
587 struct section_perm {
588 	const char *name;
589 	unsigned long start;
590 	unsigned long end;
591 	pmdval_t mask;
592 	pmdval_t prot;
593 	pmdval_t clear;
594 };
595 
596 /* First section-aligned location at or after __start_rodata. */
597 extern char __start_rodata_section_aligned[];
598 
599 static struct section_perm nx_perms[] = {
600 	/* Make pages tables, etc before _stext RW (set NX). */
601 	{
602 		.name	= "pre-text NX",
603 		.start	= PAGE_OFFSET,
604 		.end	= (unsigned long)_stext,
605 		.mask	= ~PMD_SECT_XN,
606 		.prot	= PMD_SECT_XN,
607 	},
608 	/* Make init RW (set NX). */
609 	{
610 		.name	= "init NX",
611 		.start	= (unsigned long)__init_begin,
612 		.end	= (unsigned long)_sdata,
613 		.mask	= ~PMD_SECT_XN,
614 		.prot	= PMD_SECT_XN,
615 	},
616 	/* Make rodata NX (set RO in ro_perms below). */
617 	{
618 		.name	= "rodata NX",
619 		.start  = (unsigned long)__start_rodata_section_aligned,
620 		.end    = (unsigned long)__init_begin,
621 		.mask   = ~PMD_SECT_XN,
622 		.prot   = PMD_SECT_XN,
623 	},
624 };
625 
626 static struct section_perm ro_perms[] = {
627 	/* Make kernel code and rodata RX (set RO). */
628 	{
629 		.name	= "text/rodata RO",
630 		.start  = (unsigned long)_stext,
631 		.end    = (unsigned long)__init_begin,
632 #ifdef CONFIG_ARM_LPAE
633 		.mask   = ~(L_PMD_SECT_RDONLY | PMD_SECT_AP2),
634 		.prot   = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
635 #else
636 		.mask   = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
637 		.prot   = PMD_SECT_APX | PMD_SECT_AP_WRITE,
638 		.clear  = PMD_SECT_AP_WRITE,
639 #endif
640 	},
641 };
642 
643 /*
644  * Updates section permissions only for the current mm (sections are
645  * copied into each mm). During startup, this is the init_mm. Is only
646  * safe to be called with preemption disabled, as under stop_machine().
647  */
648 static inline void section_update(unsigned long addr, pmdval_t mask,
649 				  pmdval_t prot, struct mm_struct *mm)
650 {
651 	pmd_t *pmd;
652 
653 	pmd = pmd_offset(pud_offset(pgd_offset(mm, addr), addr), addr);
654 
655 #ifdef CONFIG_ARM_LPAE
656 	pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
657 #else
658 	if (addr & SECTION_SIZE)
659 		pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
660 	else
661 		pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
662 #endif
663 	flush_pmd_entry(pmd);
664 	local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
665 }
666 
667 /* Make sure extended page tables are in use. */
668 static inline bool arch_has_strict_perms(void)
669 {
670 	if (cpu_architecture() < CPU_ARCH_ARMv6)
671 		return false;
672 
673 	return !!(get_cr() & CR_XP);
674 }
675 
676 void set_section_perms(struct section_perm *perms, int n, bool set,
677 			struct mm_struct *mm)
678 {
679 	size_t i;
680 	unsigned long addr;
681 
682 	if (!arch_has_strict_perms())
683 		return;
684 
685 	for (i = 0; i < n; i++) {
686 		if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
687 		    !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
688 			pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
689 				perms[i].name, perms[i].start, perms[i].end,
690 				SECTION_SIZE);
691 			continue;
692 		}
693 
694 		for (addr = perms[i].start;
695 		     addr < perms[i].end;
696 		     addr += SECTION_SIZE)
697 			section_update(addr, perms[i].mask,
698 				set ? perms[i].prot : perms[i].clear, mm);
699 	}
700 
701 }
702 
703 /**
704  * update_sections_early intended to be called only through stop_machine
705  * framework and executed by only one CPU while all other CPUs will spin and
706  * wait, so no locking is required in this function.
707  */
708 static void update_sections_early(struct section_perm perms[], int n)
709 {
710 	struct task_struct *t, *s;
711 
712 	for_each_process(t) {
713 		if (t->flags & PF_KTHREAD)
714 			continue;
715 		for_each_thread(t, s)
716 			set_section_perms(perms, n, true, s->mm);
717 	}
718 	set_section_perms(perms, n, true, current->active_mm);
719 	set_section_perms(perms, n, true, &init_mm);
720 }
721 
722 static int __fix_kernmem_perms(void *unused)
723 {
724 	update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
725 	return 0;
726 }
727 
728 static void fix_kernmem_perms(void)
729 {
730 	stop_machine(__fix_kernmem_perms, NULL, NULL);
731 }
732 
733 static int __mark_rodata_ro(void *unused)
734 {
735 	update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
736 	return 0;
737 }
738 
739 static int kernel_set_to_readonly __read_mostly;
740 
741 void mark_rodata_ro(void)
742 {
743 	kernel_set_to_readonly = 1;
744 	stop_machine(__mark_rodata_ro, NULL, NULL);
745 	debug_checkwx();
746 }
747 
748 void set_kernel_text_rw(void)
749 {
750 	if (!kernel_set_to_readonly)
751 		return;
752 
753 	set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), false,
754 				current->active_mm);
755 }
756 
757 void set_kernel_text_ro(void)
758 {
759 	if (!kernel_set_to_readonly)
760 		return;
761 
762 	set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), true,
763 				current->active_mm);
764 }
765 
766 #else
767 static inline void fix_kernmem_perms(void) { }
768 #endif /* CONFIG_STRICT_KERNEL_RWX */
769 
770 void free_initmem(void)
771 {
772 	fix_kernmem_perms();
773 
774 	poison_init_mem(__init_begin, __init_end - __init_begin);
775 	if (!machine_is_integrator() && !machine_is_cintegrator())
776 		free_initmem_default(-1);
777 }
778 
779 #ifdef CONFIG_BLK_DEV_INITRD
780 
781 static int keep_initrd;
782 
783 void free_initrd_mem(unsigned long start, unsigned long end)
784 {
785 	if (!keep_initrd) {
786 		if (start == initrd_start)
787 			start = round_down(start, PAGE_SIZE);
788 		if (end == initrd_end)
789 			end = round_up(end, PAGE_SIZE);
790 
791 		poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
792 		free_reserved_area((void *)start, (void *)end, -1, "initrd");
793 	}
794 }
795 
796 static int __init keepinitrd_setup(char *__unused)
797 {
798 	keep_initrd = 1;
799 	return 1;
800 }
801 
802 __setup("keepinitrd", keepinitrd_setup);
803 #endif
804