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 void __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
267 struct 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. */
277 extern char __start_rodata_section_aligned[];
278 
279 static 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 
306 static 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  */
328 static 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_offset(pgd_offset(mm, addr), addr), addr), 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((pmd_val(pmd[1]) & mask) | prot);
340 	else
341 		pmd[0] = __pmd((pmd_val(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. */
348 static 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 
356 static 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, perms[i].mask,
378 				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  */
388 static 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, true, s->mm);
398 	}
399 	set_section_perms(perms, n, true, current->active_mm);
400 	set_section_perms(perms, n, true, &init_mm);
401 }
402 
403 static int __fix_kernmem_perms(void *unused)
404 {
405 	update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
406 	return 0;
407 }
408 
409 static void fix_kernmem_perms(void)
410 {
411 	stop_machine(__fix_kernmem_perms, NULL, NULL);
412 }
413 
414 static int __mark_rodata_ro(void *unused)
415 {
416 	update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
417 	return 0;
418 }
419 
420 void mark_rodata_ro(void)
421 {
422 	stop_machine(__mark_rodata_ro, NULL, NULL);
423 	arm_debug_checkwx();
424 }
425 
426 #else
427 static inline void fix_kernmem_perms(void) { }
428 #endif /* CONFIG_STRICT_KERNEL_RWX */
429 
430 void free_initmem(void)
431 {
432 	fix_kernmem_perms();
433 
434 	poison_init_mem(__init_begin, __init_end - __init_begin);
435 	if (!machine_is_integrator() && !machine_is_cintegrator())
436 		free_initmem_default(-1);
437 }
438 
439 #ifdef CONFIG_BLK_DEV_INITRD
440 void 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((void *)start, PAGE_ALIGN(end) - start);
448 	free_reserved_area((void *)start, (void *)end, -1, "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
466 static struct execmem_info execmem_info __ro_after_init;
467 
468 struct 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