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
45unsigned 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
53static 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
64static 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
74static 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
84phys_addr_t arm_dma_zone_size __read_mostly;
85EXPORT_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 */
93phys_addr_t arm_dma_limit;
94unsigned long arm_dma_pfn_limit;
95#endif
96
97void __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
109static 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
125int 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}
145EXPORT_SYMBOL(pfn_valid);
146#endif
147
148static bool arm_memblock_steal_permitted = true;
149
150phys_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
168void 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
183void __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
205void __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 */
232static 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
239static 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 */
271void __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
305struct 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. */
315extern char __start_rodata_section_aligned[];
316
317static 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
344static 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 */
366static 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. */
386static 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
394static 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 */
426static 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
441static int __fix_kernmem_perms(void *unused)
442{
443	update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
444	return 0;
445}
446
447static void fix_kernmem_perms(void)
448{
449	stop_machine(__fix_kernmem_perms, NULL, NULL);
450}
451
452static int __mark_rodata_ro(void *unused)
453{
454	update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
455	return 0;
456}
457
458void mark_rodata_ro(void)
459{
460	stop_machine(__mark_rodata_ro, NULL, NULL);
461	arm_debug_checkwx();
462}
463
464#else
465static inline void fix_kernmem_perms(void) { }
466#endif /* CONFIG_STRICT_KERNEL_RWX */
467
468void 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
478void 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