xref: /openbmc/linux/arch/arm/mm/init.c (revision 47010c04) 
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 
26 #include <asm/cp15.h>
27 #include <asm/mach-types.h>
28 #include <asm/memblock.h>
29 #include <asm/memory.h>
30 #include <asm/prom.h>
31 #include <asm/sections.h>
32 #include <asm/setup.h>
33 #include <asm/set_memory.h>
34 #include <asm/system_info.h>
35 #include <asm/tlb.h>
36 #include <asm/fixmap.h>
37 #include <asm/ptdump.h>
38 
39 #include <asm/mach/arch.h>
40 #include <asm/mach/map.h>
41 
42 #include "mm.h"
43 
44 #ifdef CONFIG_CPU_CP15_MMU
45 unsigned long __init __clear_cr(unsigned long mask)
46 {
47 	cr_alignment = cr_alignment & ~mask;
48 	return cr_alignment;
49 }
50 #endif
51 
52 #ifdef CONFIG_BLK_DEV_INITRD
53 static int __init parse_tag_initrd(const struct tag *tag)
54 {
55 	pr_warn("ATAG_INITRD is deprecated; "
56 		"please update your bootloader.\n");
57 	phys_initrd_start = __virt_to_phys(tag->u.initrd.start);
58 	phys_initrd_size = tag->u.initrd.size;
59 	return 0;
60 }
61 
62 __tagtable(ATAG_INITRD, parse_tag_initrd);
63 
64 static int __init parse_tag_initrd2(const struct tag *tag)
65 {
66 	phys_initrd_start = tag->u.initrd.start;
67 	phys_initrd_size = tag->u.initrd.size;
68 	return 0;
69 }
70 
71 __tagtable(ATAG_INITRD2, parse_tag_initrd2);
72 #endif
73 
74 static void __init find_limits(unsigned long *min, unsigned long *max_low,
75 			       unsigned long *max_high)
76 {
77 	*max_low = PFN_DOWN(memblock_get_current_limit());
78 	*min = PFN_UP(memblock_start_of_DRAM());
79 	*max_high = PFN_DOWN(memblock_end_of_DRAM());
80 }
81 
82 #ifdef CONFIG_ZONE_DMA
83 
84 phys_addr_t arm_dma_zone_size __read_mostly;
85 EXPORT_SYMBOL(arm_dma_zone_size);
86 
87 /*
88  * The DMA mask corresponding to the maximum bus address allocatable
89  * using GFP_DMA.  The default here places no restriction on DMA
90  * allocations.  This must be the smallest DMA mask in the system,
91  * so a successful GFP_DMA allocation will always satisfy this.
92  */
93 phys_addr_t arm_dma_limit;
94 unsigned long arm_dma_pfn_limit;
95 #endif
96 
97 void __init setup_dma_zone(const struct machine_desc *mdesc)
98 {
99 #ifdef CONFIG_ZONE_DMA
100 	if (mdesc->dma_zone_size) {
101 		arm_dma_zone_size = mdesc->dma_zone_size;
102 		arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
103 	} else
104 		arm_dma_limit = 0xffffffff;
105 	arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT;
106 #endif
107 }
108 
109 static void __init zone_sizes_init(unsigned long min, unsigned long max_low,
110 	unsigned long max_high)
111 {
112 	unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
113 
114 #ifdef CONFIG_ZONE_DMA
115 	max_zone_pfn[ZONE_DMA] = min(arm_dma_pfn_limit, max_low);
116 #endif
117 	max_zone_pfn[ZONE_NORMAL] = max_low;
118 #ifdef CONFIG_HIGHMEM
119 	max_zone_pfn[ZONE_HIGHMEM] = max_high;
120 #endif
121 	free_area_init(max_zone_pfn);
122 }
123 
124 #ifdef CONFIG_HAVE_ARCH_PFN_VALID
125 int pfn_valid(unsigned long pfn)
126 {
127 	phys_addr_t addr = __pfn_to_phys(pfn);
128 	unsigned long pageblock_size = PAGE_SIZE * pageblock_nr_pages;
129 
130 	if (__phys_to_pfn(addr) != pfn)
131 		return 0;
132 
133 	/*
134 	 * If address less than pageblock_size bytes away from a present
135 	 * memory chunk there still will be a memory map entry for it
136 	 * because we round freed memory map to the pageblock boundaries.
137 	 */
138 	if (memblock_overlaps_region(&memblock.memory,
139 				     ALIGN_DOWN(addr, pageblock_size),
140 				     pageblock_size))
141 		return 1;
142 
143 	return 0;
144 }
145 EXPORT_SYMBOL(pfn_valid);
146 #endif
147 
148 static bool arm_memblock_steal_permitted = true;
149 
150 phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
151 {
152 	phys_addr_t phys;
153 
154 	BUG_ON(!arm_memblock_steal_permitted);
155 
156 	phys = memblock_phys_alloc(size, align);
157 	if (!phys)
158 		panic("Failed to steal %pa bytes at %pS\n",
159 		      &size, (void *)_RET_IP_);
160 
161 	memblock_phys_free(phys, size);
162 	memblock_remove(phys, size);
163 
164 	return phys;
165 }
166 
167 #ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND
168 void check_cpu_icache_size(int cpuid)
169 {
170 	u32 size, ctr;
171 
172 	asm("mrc p15, 0, %0, c0, c0, 1" : "=r" (ctr));
173 
174 	size = 1 << ((ctr & 0xf) + 2);
175 	if (cpuid != 0 && icache_size != size)
176 		pr_info("CPU%u: detected I-Cache line size mismatch, workaround enabled\n",
177 			cpuid);
178 	if (icache_size > size)
179 		icache_size = size;
180 }
181 #endif
182 
183 void __init arm_memblock_init(const struct machine_desc *mdesc)
184 {
185 	/* Register the kernel text, kernel data and initrd with memblock. */
186 	memblock_reserve(__pa(KERNEL_START), KERNEL_END - KERNEL_START);
187 
188 	reserve_initrd_mem();
189 
190 	arm_mm_memblock_reserve();
191 
192 	/* reserve any platform specific memblock areas */
193 	if (mdesc->reserve)
194 		mdesc->reserve();
195 
196 	early_init_fdt_scan_reserved_mem();
197 
198 	/* reserve memory for DMA contiguous allocations */
199 	dma_contiguous_reserve(arm_dma_limit);
200 
201 	arm_memblock_steal_permitted = false;
202 	memblock_dump_all();
203 }
204 
205 void __init bootmem_init(void)
206 {
207 	memblock_allow_resize();
208 
209 	find_limits(&min_low_pfn, &max_low_pfn, &max_pfn);
210 
211 	early_memtest((phys_addr_t)min_low_pfn << PAGE_SHIFT,
212 		      (phys_addr_t)max_low_pfn << PAGE_SHIFT);
213 
214 	/*
215 	 * sparse_init() tries to allocate memory from memblock, so must be
216 	 * done after the fixed reservations
217 	 */
218 	sparse_init();
219 
220 	/*
221 	 * Now free the memory - free_area_init needs
222 	 * the sparse mem_map arrays initialized by sparse_init()
223 	 * for memmap_init_zone(), otherwise all PFNs are invalid.
224 	 */
225 	zone_sizes_init(min_low_pfn, max_low_pfn, max_pfn);
226 }
227 
228 /*
229  * Poison init memory with an undefined instruction (ARM) or a branch to an
230  * undefined instruction (Thumb).
231  */
232 static inline void poison_init_mem(void *s, size_t count)
233 {
234 	u32 *p = (u32 *)s;
235 	for (; count != 0; count -= 4)
236 		*p++ = 0xe7fddef0;
237 }
238 
239 static void __init free_highpages(void)
240 {
241 #ifdef CONFIG_HIGHMEM
242 	unsigned long max_low = max_low_pfn;
243 	phys_addr_t range_start, range_end;
244 	u64 i;
245 
246 	/* set highmem page free */
247 	for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
248 				&range_start, &range_end, NULL) {
249 		unsigned long start = PFN_UP(range_start);
250 		unsigned long end = PFN_DOWN(range_end);
251 
252 		/* Ignore complete lowmem entries */
253 		if (end <= max_low)
254 			continue;
255 
256 		/* Truncate partial highmem entries */
257 		if (start < max_low)
258 			start = max_low;
259 
260 		for (; start < end; start++)
261 			free_highmem_page(pfn_to_page(start));
262 	}
263 #endif
264 }
265 
266 /*
267  * mem_init() marks the free areas in the mem_map and tells us how much
268  * memory is free.  This is done after various parts of the system have
269  * claimed their memory after the kernel image.
270  */
271 void __init mem_init(void)
272 {
273 #ifdef CONFIG_ARM_LPAE
274 	if (swiotlb_force == SWIOTLB_FORCE ||
275 	    max_pfn > arm_dma_pfn_limit)
276 		swiotlb_init(1);
277 	else
278 		swiotlb_force = SWIOTLB_NO_FORCE;
279 #endif
280 
281 	set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
282 
283 	/* this will put all unused low memory onto the freelists */
284 	memblock_free_all();
285 
286 #ifdef CONFIG_SA1111
287 	/* now that our DMA memory is actually so designated, we can free it */
288 	free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
289 #endif
290 
291 	free_highpages();
292 
293 	/*
294 	 * Check boundaries twice: Some fundamental inconsistencies can
295 	 * be detected at build time already.
296 	 */
297 #ifdef CONFIG_MMU
298 	BUILD_BUG_ON(TASK_SIZE				> MODULES_VADDR);
299 	BUG_ON(TASK_SIZE 				> MODULES_VADDR);
300 #endif
301 
302 #ifdef CONFIG_HIGHMEM
303 	BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
304 	BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE	> PAGE_OFFSET);
305 #endif
306 }
307 
308 #ifdef CONFIG_STRICT_KERNEL_RWX
309 struct section_perm {
310 	const char *name;
311 	unsigned long start;
312 	unsigned long end;
313 	pmdval_t mask;
314 	pmdval_t prot;
315 	pmdval_t clear;
316 };
317 
318 /* First section-aligned location at or after __start_rodata. */
319 extern char __start_rodata_section_aligned[];
320 
321 static struct section_perm nx_perms[] = {
322 	/* Make pages tables, etc before _stext RW (set NX). */
323 	{
324 		.name	= "pre-text NX",
325 		.start	= PAGE_OFFSET,
326 		.end	= (unsigned long)_stext,
327 		.mask	= ~PMD_SECT_XN,
328 		.prot	= PMD_SECT_XN,
329 	},
330 	/* Make init RW (set NX). */
331 	{
332 		.name	= "init NX",
333 		.start	= (unsigned long)__init_begin,
334 		.end	= (unsigned long)_sdata,
335 		.mask	= ~PMD_SECT_XN,
336 		.prot	= PMD_SECT_XN,
337 	},
338 	/* Make rodata NX (set RO in ro_perms below). */
339 	{
340 		.name	= "rodata NX",
341 		.start  = (unsigned long)__start_rodata_section_aligned,
342 		.end    = (unsigned long)__init_begin,
343 		.mask   = ~PMD_SECT_XN,
344 		.prot   = PMD_SECT_XN,
345 	},
346 };
347 
348 static struct section_perm ro_perms[] = {
349 	/* Make kernel code and rodata RX (set RO). */
350 	{
351 		.name	= "text/rodata RO",
352 		.start  = (unsigned long)_stext,
353 		.end    = (unsigned long)__init_begin,
354 #ifdef CONFIG_ARM_LPAE
355 		.mask   = ~(L_PMD_SECT_RDONLY | PMD_SECT_AP2),
356 		.prot   = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
357 #else
358 		.mask   = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
359 		.prot   = PMD_SECT_APX | PMD_SECT_AP_WRITE,
360 		.clear  = PMD_SECT_AP_WRITE,
361 #endif
362 	},
363 };
364 
365 /*
366  * Updates section permissions only for the current mm (sections are
367  * copied into each mm). During startup, this is the init_mm. Is only
368  * safe to be called with preemption disabled, as under stop_machine().
369  */
370 static inline void section_update(unsigned long addr, pmdval_t mask,
371 				  pmdval_t prot, struct mm_struct *mm)
372 {
373 	pmd_t *pmd;
374 
375 	pmd = pmd_offset(pud_offset(p4d_offset(pgd_offset(mm, addr), addr), addr), addr);
376 
377 #ifdef CONFIG_ARM_LPAE
378 	pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
379 #else
380 	if (addr & SECTION_SIZE)
381 		pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
382 	else
383 		pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
384 #endif
385 	flush_pmd_entry(pmd);
386 	local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
387 }
388 
389 /* Make sure extended page tables are in use. */
390 static inline bool arch_has_strict_perms(void)
391 {
392 	if (cpu_architecture() < CPU_ARCH_ARMv6)
393 		return false;
394 
395 	return !!(get_cr() & CR_XP);
396 }
397 
398 static void set_section_perms(struct section_perm *perms, int n, bool set,
399 			      struct mm_struct *mm)
400 {
401 	size_t i;
402 	unsigned long addr;
403 
404 	if (!arch_has_strict_perms())
405 		return;
406 
407 	for (i = 0; i < n; i++) {
408 		if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
409 		    !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
410 			pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
411 				perms[i].name, perms[i].start, perms[i].end,
412 				SECTION_SIZE);
413 			continue;
414 		}
415 
416 		for (addr = perms[i].start;
417 		     addr < perms[i].end;
418 		     addr += SECTION_SIZE)
419 			section_update(addr, perms[i].mask,
420 				set ? perms[i].prot : perms[i].clear, mm);
421 	}
422 
423 }
424 
425 /**
426  * update_sections_early intended to be called only through stop_machine
427  * framework and executed by only one CPU while all other CPUs will spin and
428  * wait, so no locking is required in this function.
429  */
430 static void update_sections_early(struct section_perm perms[], int n)
431 {
432 	struct task_struct *t, *s;
433 
434 	for_each_process(t) {
435 		if (t->flags & PF_KTHREAD)
436 			continue;
437 		for_each_thread(t, s)
438 			if (s->mm)
439 				set_section_perms(perms, n, true, s->mm);
440 	}
441 	set_section_perms(perms, n, true, current->active_mm);
442 	set_section_perms(perms, n, true, &init_mm);
443 }
444 
445 static int __fix_kernmem_perms(void *unused)
446 {
447 	update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
448 	return 0;
449 }
450 
451 static void fix_kernmem_perms(void)
452 {
453 	stop_machine(__fix_kernmem_perms, NULL, NULL);
454 }
455 
456 static int __mark_rodata_ro(void *unused)
457 {
458 	update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
459 	return 0;
460 }
461 
462 void mark_rodata_ro(void)
463 {
464 	stop_machine(__mark_rodata_ro, NULL, NULL);
465 	debug_checkwx();
466 }
467 
468 #else
469 static inline void fix_kernmem_perms(void) { }
470 #endif /* CONFIG_STRICT_KERNEL_RWX */
471 
472 void free_initmem(void)
473 {
474 	fix_kernmem_perms();
475 
476 	poison_init_mem(__init_begin, __init_end - __init_begin);
477 	if (!machine_is_integrator() && !machine_is_cintegrator())
478 		free_initmem_default(-1);
479 }
480 
481 #ifdef CONFIG_BLK_DEV_INITRD
482 void free_initrd_mem(unsigned long start, unsigned long end)
483 {
484 	if (start == initrd_start)
485 		start = round_down(start, PAGE_SIZE);
486 	if (end == initrd_end)
487 		end = round_up(end, PAGE_SIZE);
488 
489 	poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
490 	free_reserved_area((void *)start, (void *)end, -1, "initrd");
491 }
492 #endif
493