xref: /openbmc/linux/arch/arm/mm/init.c (revision 293d5b43)
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/export.h>
17 #include <linux/nodemask.h>
18 #include <linux/initrd.h>
19 #include <linux/of_fdt.h>
20 #include <linux/highmem.h>
21 #include <linux/gfp.h>
22 #include <linux/memblock.h>
23 #include <linux/dma-contiguous.h>
24 #include <linux/sizes.h>
25 #include <linux/stop_machine.h>
26 
27 #include <asm/cp15.h>
28 #include <asm/mach-types.h>
29 #include <asm/memblock.h>
30 #include <asm/prom.h>
31 #include <asm/sections.h>
32 #include <asm/setup.h>
33 #include <asm/system_info.h>
34 #include <asm/tlb.h>
35 #include <asm/fixmap.h>
36 
37 #include <asm/mach/arch.h>
38 #include <asm/mach/map.h>
39 
40 #include "mm.h"
41 
42 #ifdef CONFIG_CPU_CP15_MMU
43 unsigned long __init __clear_cr(unsigned long mask)
44 {
45 	cr_alignment = cr_alignment & ~mask;
46 	return cr_alignment;
47 }
48 #endif
49 
50 static phys_addr_t phys_initrd_start __initdata = 0;
51 static unsigned long phys_initrd_size __initdata = 0;
52 
53 static int __init early_initrd(char *p)
54 {
55 	phys_addr_t start;
56 	unsigned long size;
57 	char *endp;
58 
59 	start = memparse(p, &endp);
60 	if (*endp == ',') {
61 		size = memparse(endp + 1, NULL);
62 
63 		phys_initrd_start = start;
64 		phys_initrd_size = size;
65 	}
66 	return 0;
67 }
68 early_param("initrd", early_initrd);
69 
70 static int __init parse_tag_initrd(const struct tag *tag)
71 {
72 	pr_warn("ATAG_INITRD is deprecated; "
73 		"please update your bootloader.\n");
74 	phys_initrd_start = __virt_to_phys(tag->u.initrd.start);
75 	phys_initrd_size = tag->u.initrd.size;
76 	return 0;
77 }
78 
79 __tagtable(ATAG_INITRD, parse_tag_initrd);
80 
81 static int __init parse_tag_initrd2(const struct tag *tag)
82 {
83 	phys_initrd_start = tag->u.initrd.start;
84 	phys_initrd_size = tag->u.initrd.size;
85 	return 0;
86 }
87 
88 __tagtable(ATAG_INITRD2, parse_tag_initrd2);
89 
90 static void __init find_limits(unsigned long *min, unsigned long *max_low,
91 			       unsigned long *max_high)
92 {
93 	*max_low = PFN_DOWN(memblock_get_current_limit());
94 	*min = PFN_UP(memblock_start_of_DRAM());
95 	*max_high = PFN_DOWN(memblock_end_of_DRAM());
96 }
97 
98 #ifdef CONFIG_ZONE_DMA
99 
100 phys_addr_t arm_dma_zone_size __read_mostly;
101 EXPORT_SYMBOL(arm_dma_zone_size);
102 
103 /*
104  * The DMA mask corresponding to the maximum bus address allocatable
105  * using GFP_DMA.  The default here places no restriction on DMA
106  * allocations.  This must be the smallest DMA mask in the system,
107  * so a successful GFP_DMA allocation will always satisfy this.
108  */
109 phys_addr_t arm_dma_limit;
110 unsigned long arm_dma_pfn_limit;
111 
112 static void __init arm_adjust_dma_zone(unsigned long *size, unsigned long *hole,
113 	unsigned long dma_size)
114 {
115 	if (size[0] <= dma_size)
116 		return;
117 
118 	size[ZONE_NORMAL] = size[0] - dma_size;
119 	size[ZONE_DMA] = dma_size;
120 	hole[ZONE_NORMAL] = hole[0];
121 	hole[ZONE_DMA] = 0;
122 }
123 #endif
124 
125 void __init setup_dma_zone(const struct machine_desc *mdesc)
126 {
127 #ifdef CONFIG_ZONE_DMA
128 	if (mdesc->dma_zone_size) {
129 		arm_dma_zone_size = mdesc->dma_zone_size;
130 		arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
131 	} else
132 		arm_dma_limit = 0xffffffff;
133 	arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT;
134 #endif
135 }
136 
137 static void __init zone_sizes_init(unsigned long min, unsigned long max_low,
138 	unsigned long max_high)
139 {
140 	unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
141 	struct memblock_region *reg;
142 
143 	/*
144 	 * initialise the zones.
145 	 */
146 	memset(zone_size, 0, sizeof(zone_size));
147 
148 	/*
149 	 * The memory size has already been determined.  If we need
150 	 * to do anything fancy with the allocation of this memory
151 	 * to the zones, now is the time to do it.
152 	 */
153 	zone_size[0] = max_low - min;
154 #ifdef CONFIG_HIGHMEM
155 	zone_size[ZONE_HIGHMEM] = max_high - max_low;
156 #endif
157 
158 	/*
159 	 * Calculate the size of the holes.
160 	 *  holes = node_size - sum(bank_sizes)
161 	 */
162 	memcpy(zhole_size, zone_size, sizeof(zhole_size));
163 	for_each_memblock(memory, reg) {
164 		unsigned long start = memblock_region_memory_base_pfn(reg);
165 		unsigned long end = memblock_region_memory_end_pfn(reg);
166 
167 		if (start < max_low) {
168 			unsigned long low_end = min(end, max_low);
169 			zhole_size[0] -= low_end - start;
170 		}
171 #ifdef CONFIG_HIGHMEM
172 		if (end > max_low) {
173 			unsigned long high_start = max(start, max_low);
174 			zhole_size[ZONE_HIGHMEM] -= end - high_start;
175 		}
176 #endif
177 	}
178 
179 #ifdef CONFIG_ZONE_DMA
180 	/*
181 	 * Adjust the sizes according to any special requirements for
182 	 * this machine type.
183 	 */
184 	if (arm_dma_zone_size)
185 		arm_adjust_dma_zone(zone_size, zhole_size,
186 			arm_dma_zone_size >> PAGE_SHIFT);
187 #endif
188 
189 	free_area_init_node(0, zone_size, min, zhole_size);
190 }
191 
192 #ifdef CONFIG_HAVE_ARCH_PFN_VALID
193 int pfn_valid(unsigned long pfn)
194 {
195 	return memblock_is_map_memory(__pfn_to_phys(pfn));
196 }
197 EXPORT_SYMBOL(pfn_valid);
198 #endif
199 
200 #ifndef CONFIG_SPARSEMEM
201 static void __init arm_memory_present(void)
202 {
203 }
204 #else
205 static void __init arm_memory_present(void)
206 {
207 	struct memblock_region *reg;
208 
209 	for_each_memblock(memory, reg)
210 		memory_present(0, memblock_region_memory_base_pfn(reg),
211 			       memblock_region_memory_end_pfn(reg));
212 }
213 #endif
214 
215 static bool arm_memblock_steal_permitted = true;
216 
217 phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
218 {
219 	phys_addr_t phys;
220 
221 	BUG_ON(!arm_memblock_steal_permitted);
222 
223 	phys = memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ANYWHERE);
224 	memblock_free(phys, size);
225 	memblock_remove(phys, size);
226 
227 	return phys;
228 }
229 
230 void __init arm_memblock_init(const struct machine_desc *mdesc)
231 {
232 	/* Register the kernel text, kernel data and initrd with memblock. */
233 #ifdef CONFIG_XIP_KERNEL
234 	memblock_reserve(__pa(_sdata), _end - _sdata);
235 #else
236 	memblock_reserve(__pa(_stext), _end - _stext);
237 #endif
238 #ifdef CONFIG_BLK_DEV_INITRD
239 	/* FDT scan will populate initrd_start */
240 	if (initrd_start && !phys_initrd_size) {
241 		phys_initrd_start = __virt_to_phys(initrd_start);
242 		phys_initrd_size = initrd_end - initrd_start;
243 	}
244 	initrd_start = initrd_end = 0;
245 	if (phys_initrd_size &&
246 	    !memblock_is_region_memory(phys_initrd_start, phys_initrd_size)) {
247 		pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",
248 		       (u64)phys_initrd_start, phys_initrd_size);
249 		phys_initrd_start = phys_initrd_size = 0;
250 	}
251 	if (phys_initrd_size &&
252 	    memblock_is_region_reserved(phys_initrd_start, phys_initrd_size)) {
253 		pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
254 		       (u64)phys_initrd_start, phys_initrd_size);
255 		phys_initrd_start = phys_initrd_size = 0;
256 	}
257 	if (phys_initrd_size) {
258 		memblock_reserve(phys_initrd_start, phys_initrd_size);
259 
260 		/* Now convert initrd to virtual addresses */
261 		initrd_start = __phys_to_virt(phys_initrd_start);
262 		initrd_end = initrd_start + phys_initrd_size;
263 	}
264 #endif
265 
266 	arm_mm_memblock_reserve();
267 
268 	/* reserve any platform specific memblock areas */
269 	if (mdesc->reserve)
270 		mdesc->reserve();
271 
272 	early_init_fdt_reserve_self();
273 	early_init_fdt_scan_reserved_mem();
274 
275 	/* reserve memory for DMA contiguous allocations */
276 	dma_contiguous_reserve(arm_dma_limit);
277 
278 	arm_memblock_steal_permitted = false;
279 	memblock_dump_all();
280 }
281 
282 void __init bootmem_init(void)
283 {
284 	unsigned long min, max_low, max_high;
285 
286 	memblock_allow_resize();
287 	max_low = max_high = 0;
288 
289 	find_limits(&min, &max_low, &max_high);
290 
291 	early_memtest((phys_addr_t)min << PAGE_SHIFT,
292 		      (phys_addr_t)max_low << PAGE_SHIFT);
293 
294 	/*
295 	 * Sparsemem tries to allocate bootmem in memory_present(),
296 	 * so must be done after the fixed reservations
297 	 */
298 	arm_memory_present();
299 
300 	/*
301 	 * sparse_init() needs the bootmem allocator up and running.
302 	 */
303 	sparse_init();
304 
305 	/*
306 	 * Now free the memory - free_area_init_node needs
307 	 * the sparse mem_map arrays initialized by sparse_init()
308 	 * for memmap_init_zone(), otherwise all PFNs are invalid.
309 	 */
310 	zone_sizes_init(min, max_low, max_high);
311 
312 	/*
313 	 * This doesn't seem to be used by the Linux memory manager any
314 	 * more, but is used by ll_rw_block.  If we can get rid of it, we
315 	 * also get rid of some of the stuff above as well.
316 	 */
317 	min_low_pfn = min;
318 	max_low_pfn = max_low;
319 	max_pfn = max_high;
320 }
321 
322 /*
323  * Poison init memory with an undefined instruction (ARM) or a branch to an
324  * undefined instruction (Thumb).
325  */
326 static inline void poison_init_mem(void *s, size_t count)
327 {
328 	u32 *p = (u32 *)s;
329 	for (; count != 0; count -= 4)
330 		*p++ = 0xe7fddef0;
331 }
332 
333 static inline void
334 free_memmap(unsigned long start_pfn, unsigned long end_pfn)
335 {
336 	struct page *start_pg, *end_pg;
337 	phys_addr_t pg, pgend;
338 
339 	/*
340 	 * Convert start_pfn/end_pfn to a struct page pointer.
341 	 */
342 	start_pg = pfn_to_page(start_pfn - 1) + 1;
343 	end_pg = pfn_to_page(end_pfn - 1) + 1;
344 
345 	/*
346 	 * Convert to physical addresses, and
347 	 * round start upwards and end downwards.
348 	 */
349 	pg = PAGE_ALIGN(__pa(start_pg));
350 	pgend = __pa(end_pg) & PAGE_MASK;
351 
352 	/*
353 	 * If there are free pages between these,
354 	 * free the section of the memmap array.
355 	 */
356 	if (pg < pgend)
357 		memblock_free_early(pg, pgend - pg);
358 }
359 
360 /*
361  * The mem_map array can get very big.  Free the unused area of the memory map.
362  */
363 static void __init free_unused_memmap(void)
364 {
365 	unsigned long start, prev_end = 0;
366 	struct memblock_region *reg;
367 
368 	/*
369 	 * This relies on each bank being in address order.
370 	 * The banks are sorted previously in bootmem_init().
371 	 */
372 	for_each_memblock(memory, reg) {
373 		start = memblock_region_memory_base_pfn(reg);
374 
375 #ifdef CONFIG_SPARSEMEM
376 		/*
377 		 * Take care not to free memmap entries that don't exist
378 		 * due to SPARSEMEM sections which aren't present.
379 		 */
380 		start = min(start,
381 				 ALIGN(prev_end, PAGES_PER_SECTION));
382 #else
383 		/*
384 		 * Align down here since the VM subsystem insists that the
385 		 * memmap entries are valid from the bank start aligned to
386 		 * MAX_ORDER_NR_PAGES.
387 		 */
388 		start = round_down(start, MAX_ORDER_NR_PAGES);
389 #endif
390 		/*
391 		 * If we had a previous bank, and there is a space
392 		 * between the current bank and the previous, free it.
393 		 */
394 		if (prev_end && prev_end < start)
395 			free_memmap(prev_end, start);
396 
397 		/*
398 		 * Align up here since the VM subsystem insists that the
399 		 * memmap entries are valid from the bank end aligned to
400 		 * MAX_ORDER_NR_PAGES.
401 		 */
402 		prev_end = ALIGN(memblock_region_memory_end_pfn(reg),
403 				 MAX_ORDER_NR_PAGES);
404 	}
405 
406 #ifdef CONFIG_SPARSEMEM
407 	if (!IS_ALIGNED(prev_end, PAGES_PER_SECTION))
408 		free_memmap(prev_end,
409 			    ALIGN(prev_end, PAGES_PER_SECTION));
410 #endif
411 }
412 
413 #ifdef CONFIG_HIGHMEM
414 static inline void free_area_high(unsigned long pfn, unsigned long end)
415 {
416 	for (; pfn < end; pfn++)
417 		free_highmem_page(pfn_to_page(pfn));
418 }
419 #endif
420 
421 static void __init free_highpages(void)
422 {
423 #ifdef CONFIG_HIGHMEM
424 	unsigned long max_low = max_low_pfn;
425 	struct memblock_region *mem, *res;
426 
427 	/* set highmem page free */
428 	for_each_memblock(memory, mem) {
429 		unsigned long start = memblock_region_memory_base_pfn(mem);
430 		unsigned long end = memblock_region_memory_end_pfn(mem);
431 
432 		/* Ignore complete lowmem entries */
433 		if (end <= max_low)
434 			continue;
435 
436 		if (memblock_is_nomap(mem))
437 			continue;
438 
439 		/* Truncate partial highmem entries */
440 		if (start < max_low)
441 			start = max_low;
442 
443 		/* Find and exclude any reserved regions */
444 		for_each_memblock(reserved, res) {
445 			unsigned long res_start, res_end;
446 
447 			res_start = memblock_region_reserved_base_pfn(res);
448 			res_end = memblock_region_reserved_end_pfn(res);
449 
450 			if (res_end < start)
451 				continue;
452 			if (res_start < start)
453 				res_start = start;
454 			if (res_start > end)
455 				res_start = end;
456 			if (res_end > end)
457 				res_end = end;
458 			if (res_start != start)
459 				free_area_high(start, res_start);
460 			start = res_end;
461 			if (start == end)
462 				break;
463 		}
464 
465 		/* And now free anything which remains */
466 		if (start < end)
467 			free_area_high(start, end);
468 	}
469 #endif
470 }
471 
472 /*
473  * mem_init() marks the free areas in the mem_map and tells us how much
474  * memory is free.  This is done after various parts of the system have
475  * claimed their memory after the kernel image.
476  */
477 void __init mem_init(void)
478 {
479 #ifdef CONFIG_HAVE_TCM
480 	/* These pointers are filled in on TCM detection */
481 	extern u32 dtcm_end;
482 	extern u32 itcm_end;
483 #endif
484 
485 	set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
486 
487 	/* this will put all unused low memory onto the freelists */
488 	free_unused_memmap();
489 	free_all_bootmem();
490 
491 #ifdef CONFIG_SA1111
492 	/* now that our DMA memory is actually so designated, we can free it */
493 	free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
494 #endif
495 
496 	free_highpages();
497 
498 	mem_init_print_info(NULL);
499 
500 #define MLK(b, t) b, t, ((t) - (b)) >> 10
501 #define MLM(b, t) b, t, ((t) - (b)) >> 20
502 #define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K)
503 
504 	pr_notice("Virtual kernel memory layout:\n"
505 			"    vector  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
506 #ifdef CONFIG_HAVE_TCM
507 			"    DTCM    : 0x%08lx - 0x%08lx   (%4ld kB)\n"
508 			"    ITCM    : 0x%08lx - 0x%08lx   (%4ld kB)\n"
509 #endif
510 			"    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
511 			"    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
512 			"    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
513 #ifdef CONFIG_HIGHMEM
514 			"    pkmap   : 0x%08lx - 0x%08lx   (%4ld MB)\n"
515 #endif
516 #ifdef CONFIG_MODULES
517 			"    modules : 0x%08lx - 0x%08lx   (%4ld MB)\n"
518 #endif
519 			"      .text : 0x%p" " - 0x%p" "   (%4td kB)\n"
520 			"      .init : 0x%p" " - 0x%p" "   (%4td kB)\n"
521 			"      .data : 0x%p" " - 0x%p" "   (%4td kB)\n"
522 			"       .bss : 0x%p" " - 0x%p" "   (%4td kB)\n",
523 
524 			MLK(UL(CONFIG_VECTORS_BASE), UL(CONFIG_VECTORS_BASE) +
525 				(PAGE_SIZE)),
526 #ifdef CONFIG_HAVE_TCM
527 			MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
528 			MLK(ITCM_OFFSET, (unsigned long) itcm_end),
529 #endif
530 			MLK(FIXADDR_START, FIXADDR_END),
531 			MLM(VMALLOC_START, VMALLOC_END),
532 			MLM(PAGE_OFFSET, (unsigned long)high_memory),
533 #ifdef CONFIG_HIGHMEM
534 			MLM(PKMAP_BASE, (PKMAP_BASE) + (LAST_PKMAP) *
535 				(PAGE_SIZE)),
536 #endif
537 #ifdef CONFIG_MODULES
538 			MLM(MODULES_VADDR, MODULES_END),
539 #endif
540 
541 			MLK_ROUNDUP(_text, _etext),
542 			MLK_ROUNDUP(__init_begin, __init_end),
543 			MLK_ROUNDUP(_sdata, _edata),
544 			MLK_ROUNDUP(__bss_start, __bss_stop));
545 
546 #undef MLK
547 #undef MLM
548 #undef MLK_ROUNDUP
549 
550 	/*
551 	 * Check boundaries twice: Some fundamental inconsistencies can
552 	 * be detected at build time already.
553 	 */
554 #ifdef CONFIG_MMU
555 	BUILD_BUG_ON(TASK_SIZE				> MODULES_VADDR);
556 	BUG_ON(TASK_SIZE 				> MODULES_VADDR);
557 #endif
558 
559 #ifdef CONFIG_HIGHMEM
560 	BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
561 	BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE	> PAGE_OFFSET);
562 #endif
563 
564 	if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) {
565 		extern int sysctl_overcommit_memory;
566 		/*
567 		 * On a machine this small we won't get
568 		 * anywhere without overcommit, so turn
569 		 * it on by default.
570 		 */
571 		sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
572 	}
573 }
574 
575 #ifdef CONFIG_DEBUG_RODATA
576 struct section_perm {
577 	const char *name;
578 	unsigned long start;
579 	unsigned long end;
580 	pmdval_t mask;
581 	pmdval_t prot;
582 	pmdval_t clear;
583 };
584 
585 /* First section-aligned location at or after __start_rodata. */
586 extern char __start_rodata_section_aligned[];
587 
588 static struct section_perm nx_perms[] = {
589 	/* Make pages tables, etc before _stext RW (set NX). */
590 	{
591 		.name	= "pre-text NX",
592 		.start	= PAGE_OFFSET,
593 		.end	= (unsigned long)_stext,
594 		.mask	= ~PMD_SECT_XN,
595 		.prot	= PMD_SECT_XN,
596 	},
597 	/* Make init RW (set NX). */
598 	{
599 		.name	= "init NX",
600 		.start	= (unsigned long)__init_begin,
601 		.end	= (unsigned long)_sdata,
602 		.mask	= ~PMD_SECT_XN,
603 		.prot	= PMD_SECT_XN,
604 	},
605 	/* Make rodata NX (set RO in ro_perms below). */
606 	{
607 		.name	= "rodata NX",
608 		.start  = (unsigned long)__start_rodata_section_aligned,
609 		.end    = (unsigned long)__init_begin,
610 		.mask   = ~PMD_SECT_XN,
611 		.prot   = PMD_SECT_XN,
612 	},
613 };
614 
615 static struct section_perm ro_perms[] = {
616 	/* Make kernel code and rodata RX (set RO). */
617 	{
618 		.name	= "text/rodata RO",
619 		.start  = (unsigned long)_stext,
620 		.end    = (unsigned long)__init_begin,
621 #ifdef CONFIG_ARM_LPAE
622 		.mask   = ~L_PMD_SECT_RDONLY,
623 		.prot   = L_PMD_SECT_RDONLY,
624 #else
625 		.mask   = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
626 		.prot   = PMD_SECT_APX | PMD_SECT_AP_WRITE,
627 		.clear  = PMD_SECT_AP_WRITE,
628 #endif
629 	},
630 };
631 
632 /*
633  * Updates section permissions only for the current mm (sections are
634  * copied into each mm). During startup, this is the init_mm. Is only
635  * safe to be called with preemption disabled, as under stop_machine().
636  */
637 static inline void section_update(unsigned long addr, pmdval_t mask,
638 				  pmdval_t prot, struct mm_struct *mm)
639 {
640 	pmd_t *pmd;
641 
642 	pmd = pmd_offset(pud_offset(pgd_offset(mm, addr), addr), addr);
643 
644 #ifdef CONFIG_ARM_LPAE
645 	pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
646 #else
647 	if (addr & SECTION_SIZE)
648 		pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
649 	else
650 		pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
651 #endif
652 	flush_pmd_entry(pmd);
653 	local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
654 }
655 
656 /* Make sure extended page tables are in use. */
657 static inline bool arch_has_strict_perms(void)
658 {
659 	if (cpu_architecture() < CPU_ARCH_ARMv6)
660 		return false;
661 
662 	return !!(get_cr() & CR_XP);
663 }
664 
665 void set_section_perms(struct section_perm *perms, int n, bool set,
666 			struct mm_struct *mm)
667 {
668 	size_t i;
669 	unsigned long addr;
670 
671 	if (!arch_has_strict_perms())
672 		return;
673 
674 	for (i = 0; i < n; i++) {
675 		if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
676 		    !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
677 			pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
678 				perms[i].name, perms[i].start, perms[i].end,
679 				SECTION_SIZE);
680 			continue;
681 		}
682 
683 		for (addr = perms[i].start;
684 		     addr < perms[i].end;
685 		     addr += SECTION_SIZE)
686 			section_update(addr, perms[i].mask,
687 				set ? perms[i].prot : perms[i].clear, mm);
688 	}
689 
690 }
691 
692 static void update_sections_early(struct section_perm perms[], int n)
693 {
694 	struct task_struct *t, *s;
695 
696 	read_lock(&tasklist_lock);
697 	for_each_process(t) {
698 		if (t->flags & PF_KTHREAD)
699 			continue;
700 		for_each_thread(t, s)
701 			set_section_perms(perms, n, true, s->mm);
702 	}
703 	read_unlock(&tasklist_lock);
704 	set_section_perms(perms, n, true, current->active_mm);
705 	set_section_perms(perms, n, true, &init_mm);
706 }
707 
708 int __fix_kernmem_perms(void *unused)
709 {
710 	update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
711 	return 0;
712 }
713 
714 void fix_kernmem_perms(void)
715 {
716 	stop_machine(__fix_kernmem_perms, NULL, NULL);
717 }
718 
719 int __mark_rodata_ro(void *unused)
720 {
721 	update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
722 	return 0;
723 }
724 
725 void mark_rodata_ro(void)
726 {
727 	stop_machine(__mark_rodata_ro, NULL, NULL);
728 }
729 
730 void set_kernel_text_rw(void)
731 {
732 	set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), false,
733 				current->active_mm);
734 }
735 
736 void set_kernel_text_ro(void)
737 {
738 	set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), true,
739 				current->active_mm);
740 }
741 
742 #else
743 static inline void fix_kernmem_perms(void) { }
744 #endif /* CONFIG_DEBUG_RODATA */
745 
746 void free_tcmmem(void)
747 {
748 #ifdef CONFIG_HAVE_TCM
749 	extern char __tcm_start, __tcm_end;
750 
751 	poison_init_mem(&__tcm_start, &__tcm_end - &__tcm_start);
752 	free_reserved_area(&__tcm_start, &__tcm_end, -1, "TCM link");
753 #endif
754 }
755 
756 void free_initmem(void)
757 {
758 	fix_kernmem_perms();
759 	free_tcmmem();
760 
761 	poison_init_mem(__init_begin, __init_end - __init_begin);
762 	if (!machine_is_integrator() && !machine_is_cintegrator())
763 		free_initmem_default(-1);
764 }
765 
766 #ifdef CONFIG_BLK_DEV_INITRD
767 
768 static int keep_initrd;
769 
770 void free_initrd_mem(unsigned long start, unsigned long end)
771 {
772 	if (!keep_initrd) {
773 		if (start == initrd_start)
774 			start = round_down(start, PAGE_SIZE);
775 		if (end == initrd_end)
776 			end = round_up(end, PAGE_SIZE);
777 
778 		poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
779 		free_reserved_area((void *)start, (void *)end, -1, "initrd");
780 	}
781 }
782 
783 static int __init keepinitrd_setup(char *__unused)
784 {
785 	keep_initrd = 1;
786 	return 1;
787 }
788 
789 __setup("keepinitrd", keepinitrd_setup);
790 #endif
791