xref: /openbmc/linux/arch/arm/mm/init.c (revision f77d1a49) 
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/page.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 	swiotlb_init(max_pfn > arm_dma_pfn_limit, SWIOTLB_VERBOSE);
275 #endif
276 
277 	set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
278 
279 	/* this will put all unused low memory onto the freelists */
280 	memblock_free_all();
281 
282 #ifdef CONFIG_SA1111
283 	/* now that our DMA memory is actually so designated, we can free it */
284 	free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
285 #endif
286 
287 	free_highpages();
288 
289 	/*
290 	 * Check boundaries twice: Some fundamental inconsistencies can
291 	 * be detected at build time already.
292 	 */
293 #ifdef CONFIG_MMU
294 	BUILD_BUG_ON(TASK_SIZE				> MODULES_VADDR);
295 	BUG_ON(TASK_SIZE 				> MODULES_VADDR);
296 #endif
297 
298 #ifdef CONFIG_HIGHMEM
299 	BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
300 	BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE	> PAGE_OFFSET);
301 #endif
302 }
303 
304 #ifdef CONFIG_STRICT_KERNEL_RWX
305 struct section_perm {
306 	const char *name;
307 	unsigned long start;
308 	unsigned long end;
309 	pmdval_t mask;
310 	pmdval_t prot;
311 	pmdval_t clear;
312 };
313 
314 /* First section-aligned location at or after __start_rodata. */
315 extern char __start_rodata_section_aligned[];
316 
317 static struct section_perm nx_perms[] = {
318 	/* Make pages tables, etc before _stext RW (set NX). */
319 	{
320 		.name	= "pre-text NX",
321 		.start	= PAGE_OFFSET,
322 		.end	= (unsigned long)_stext,
323 		.mask	= ~PMD_SECT_XN,
324 		.prot	= PMD_SECT_XN,
325 	},
326 	/* Make init RW (set NX). */
327 	{
328 		.name	= "init NX",
329 		.start	= (unsigned long)__init_begin,
330 		.end	= (unsigned long)_sdata,
331 		.mask	= ~PMD_SECT_XN,
332 		.prot	= PMD_SECT_XN,
333 	},
334 	/* Make rodata NX (set RO in ro_perms below). */
335 	{
336 		.name	= "rodata NX",
337 		.start  = (unsigned long)__start_rodata_section_aligned,
338 		.end    = (unsigned long)__init_begin,
339 		.mask   = ~PMD_SECT_XN,
340 		.prot   = PMD_SECT_XN,
341 	},
342 };
343 
344 static struct section_perm ro_perms[] = {
345 	/* Make kernel code and rodata RX (set RO). */
346 	{
347 		.name	= "text/rodata RO",
348 		.start  = (unsigned long)_stext,
349 		.end    = (unsigned long)__init_begin,
350 #ifdef CONFIG_ARM_LPAE
351 		.mask   = ~(L_PMD_SECT_RDONLY | PMD_SECT_AP2),
352 		.prot   = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
353 #else
354 		.mask   = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
355 		.prot   = PMD_SECT_APX | PMD_SECT_AP_WRITE,
356 		.clear  = PMD_SECT_AP_WRITE,
357 #endif
358 	},
359 };
360 
361 /*
362  * Updates section permissions only for the current mm (sections are
363  * copied into each mm). During startup, this is the init_mm. Is only
364  * safe to be called with preemption disabled, as under stop_machine().
365  */
366 static inline void section_update(unsigned long addr, pmdval_t mask,
367 				  pmdval_t prot, struct mm_struct *mm)
368 {
369 	pmd_t *pmd;
370 
371 	pmd = pmd_offset(pud_offset(p4d_offset(pgd_offset(mm, addr), addr), addr), addr);
372 
373 #ifdef CONFIG_ARM_LPAE
374 	pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
375 #else
376 	if (addr & SECTION_SIZE)
377 		pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
378 	else
379 		pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
380 #endif
381 	flush_pmd_entry(pmd);
382 	local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
383 }
384 
385 /* Make sure extended page tables are in use. */
386 static inline bool arch_has_strict_perms(void)
387 {
388 	if (cpu_architecture() < CPU_ARCH_ARMv6)
389 		return false;
390 
391 	return !!(get_cr() & CR_XP);
392 }
393 
394 static void set_section_perms(struct section_perm *perms, int n, bool set,
395 			      struct mm_struct *mm)
396 {
397 	size_t i;
398 	unsigned long addr;
399 
400 	if (!arch_has_strict_perms())
401 		return;
402 
403 	for (i = 0; i < n; i++) {
404 		if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
405 		    !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
406 			pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
407 				perms[i].name, perms[i].start, perms[i].end,
408 				SECTION_SIZE);
409 			continue;
410 		}
411 
412 		for (addr = perms[i].start;
413 		     addr < perms[i].end;
414 		     addr += SECTION_SIZE)
415 			section_update(addr, perms[i].mask,
416 				set ? perms[i].prot : perms[i].clear, mm);
417 	}
418 
419 }
420 
421 /**
422  * update_sections_early intended to be called only through stop_machine
423  * framework and executed by only one CPU while all other CPUs will spin and
424  * wait, so no locking is required in this function.
425  */
426 static void update_sections_early(struct section_perm perms[], int n)
427 {
428 	struct task_struct *t, *s;
429 
430 	for_each_process(t) {
431 		if (t->flags & PF_KTHREAD)
432 			continue;
433 		for_each_thread(t, s)
434 			if (s->mm)
435 				set_section_perms(perms, n, true, s->mm);
436 	}
437 	set_section_perms(perms, n, true, current->active_mm);
438 	set_section_perms(perms, n, true, &init_mm);
439 }
440 
441 static int __fix_kernmem_perms(void *unused)
442 {
443 	update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
444 	return 0;
445 }
446 
447 static void fix_kernmem_perms(void)
448 {
449 	stop_machine(__fix_kernmem_perms, NULL, NULL);
450 }
451 
452 static int __mark_rodata_ro(void *unused)
453 {
454 	update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
455 	return 0;
456 }
457 
458 void mark_rodata_ro(void)
459 {
460 	stop_machine(__mark_rodata_ro, NULL, NULL);
461 	debug_checkwx();
462 }
463 
464 #else
465 static inline void fix_kernmem_perms(void) { }
466 #endif /* CONFIG_STRICT_KERNEL_RWX */
467 
468 void free_initmem(void)
469 {
470 	fix_kernmem_perms();
471 
472 	poison_init_mem(__init_begin, __init_end - __init_begin);
473 	if (!machine_is_integrator() && !machine_is_cintegrator())
474 		free_initmem_default(-1);
475 }
476 
477 #ifdef CONFIG_BLK_DEV_INITRD
478 void free_initrd_mem(unsigned long start, unsigned long end)
479 {
480 	if (start == initrd_start)
481 		start = round_down(start, PAGE_SIZE);
482 	if (end == initrd_end)
483 		end = round_up(end, PAGE_SIZE);
484 
485 	poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
486 	free_reserved_area((void *)start, (void *)end, -1, "initrd");
487 }
488 #endif
489