xref: /linux/arch/riscv/mm/init.c (revision c6ca7616f7d5c2ce166280107ba74db1d528fcb7)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2012 Regents of the University of California
4  * Copyright (C) 2019 Western Digital Corporation or its affiliates.
5  */
6 
7 #include <linux/init.h>
8 #include <linux/mm.h>
9 #include <linux/memblock.h>
10 #include <linux/initrd.h>
11 #include <linux/swap.h>
12 #include <linux/sizes.h>
13 #include <linux/of_fdt.h>
14 #include <linux/libfdt.h>
15 #include <linux/set_memory.h>
16 #include <linux/dma-map-ops.h>
17 
18 #include <asm/fixmap.h>
19 #include <asm/tlbflush.h>
20 #include <asm/sections.h>
21 #include <asm/soc.h>
22 #include <asm/io.h>
23 #include <asm/ptdump.h>
24 #include <asm/numa.h>
25 
26 #include "../kernel/head.h"
27 
28 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
29 							__page_aligned_bss;
30 EXPORT_SYMBOL(empty_zero_page);
31 
32 extern char _start[];
33 #define DTB_EARLY_BASE_VA      PGDIR_SIZE
34 void *dtb_early_va __initdata;
35 uintptr_t dtb_early_pa __initdata;
36 
37 struct pt_alloc_ops {
38 	pte_t *(*get_pte_virt)(phys_addr_t pa);
39 	phys_addr_t (*alloc_pte)(uintptr_t va);
40 #ifndef __PAGETABLE_PMD_FOLDED
41 	pmd_t *(*get_pmd_virt)(phys_addr_t pa);
42 	phys_addr_t (*alloc_pmd)(uintptr_t va);
43 #endif
44 };
45 
46 static phys_addr_t dma32_phys_limit __ro_after_init;
47 
48 static void __init zone_sizes_init(void)
49 {
50 	unsigned long max_zone_pfns[MAX_NR_ZONES] = { 0, };
51 
52 #ifdef CONFIG_ZONE_DMA32
53 	max_zone_pfns[ZONE_DMA32] = PFN_DOWN(dma32_phys_limit);
54 #endif
55 	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
56 
57 	free_area_init(max_zone_pfns);
58 }
59 
60 static void setup_zero_page(void)
61 {
62 	memset((void *)empty_zero_page, 0, PAGE_SIZE);
63 }
64 
65 #if defined(CONFIG_MMU) && defined(CONFIG_DEBUG_VM)
66 static inline void print_mlk(char *name, unsigned long b, unsigned long t)
67 {
68 	pr_notice("%12s : 0x%08lx - 0x%08lx   (%4ld kB)\n", name, b, t,
69 		  (((t) - (b)) >> 10));
70 }
71 
72 static inline void print_mlm(char *name, unsigned long b, unsigned long t)
73 {
74 	pr_notice("%12s : 0x%08lx - 0x%08lx   (%4ld MB)\n", name, b, t,
75 		  (((t) - (b)) >> 20));
76 }
77 
78 static void print_vm_layout(void)
79 {
80 	pr_notice("Virtual kernel memory layout:\n");
81 	print_mlk("fixmap", (unsigned long)FIXADDR_START,
82 		  (unsigned long)FIXADDR_TOP);
83 	print_mlm("pci io", (unsigned long)PCI_IO_START,
84 		  (unsigned long)PCI_IO_END);
85 	print_mlm("vmemmap", (unsigned long)VMEMMAP_START,
86 		  (unsigned long)VMEMMAP_END);
87 	print_mlm("vmalloc", (unsigned long)VMALLOC_START,
88 		  (unsigned long)VMALLOC_END);
89 	print_mlm("lowmem", (unsigned long)PAGE_OFFSET,
90 		  (unsigned long)high_memory);
91 }
92 #else
93 static void print_vm_layout(void) { }
94 #endif /* CONFIG_DEBUG_VM */
95 
96 void __init mem_init(void)
97 {
98 #ifdef CONFIG_FLATMEM
99 	BUG_ON(!mem_map);
100 #endif /* CONFIG_FLATMEM */
101 
102 	high_memory = (void *)(__va(PFN_PHYS(max_low_pfn)));
103 	memblock_free_all();
104 
105 	mem_init_print_info(NULL);
106 	print_vm_layout();
107 }
108 
109 void __init setup_bootmem(void)
110 {
111 	phys_addr_t mem_start = 0;
112 	phys_addr_t start, end = 0;
113 	phys_addr_t vmlinux_end = __pa_symbol(&_end);
114 	phys_addr_t vmlinux_start = __pa_symbol(&_start);
115 	u64 i;
116 
117 	/* Find the memory region containing the kernel */
118 	for_each_mem_range(i, &start, &end) {
119 		phys_addr_t size = end - start;
120 		if (!mem_start)
121 			mem_start = start;
122 		if (start <= vmlinux_start && vmlinux_end <= end)
123 			BUG_ON(size == 0);
124 	}
125 
126 	/*
127 	 * The maximal physical memory size is -PAGE_OFFSET.
128 	 * Make sure that any memory beyond mem_start + (-PAGE_OFFSET) is removed
129 	 * as it is unusable by kernel.
130 	 */
131 	memblock_enforce_memory_limit(-PAGE_OFFSET);
132 
133 	/* Reserve from the start of the kernel to the end of the kernel */
134 	memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
135 
136 	max_pfn = PFN_DOWN(memblock_end_of_DRAM());
137 	max_low_pfn = max_pfn;
138 	dma32_phys_limit = min(4UL * SZ_1G, (unsigned long)PFN_PHYS(max_low_pfn));
139 	set_max_mapnr(max_low_pfn);
140 
141 	reserve_initrd_mem();
142 	/*
143 	 * If DTB is built in, no need to reserve its memblock.
144 	 * Otherwise, do reserve it but avoid using
145 	 * early_init_fdt_reserve_self() since __pa() does
146 	 * not work for DTB pointers that are fixmap addresses
147 	 */
148 	if (!IS_ENABLED(CONFIG_BUILTIN_DTB))
149 		memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));
150 
151 	early_init_fdt_scan_reserved_mem();
152 	dma_contiguous_reserve(dma32_phys_limit);
153 	memblock_allow_resize();
154 }
155 
156 #ifdef CONFIG_MMU
157 static struct pt_alloc_ops pt_ops;
158 
159 unsigned long va_pa_offset;
160 EXPORT_SYMBOL(va_pa_offset);
161 unsigned long pfn_base;
162 EXPORT_SYMBOL(pfn_base);
163 
164 pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
165 pgd_t trampoline_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
166 pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss;
167 
168 #define MAX_EARLY_MAPPING_SIZE	SZ_128M
169 
170 pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
171 
172 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot)
173 {
174 	unsigned long addr = __fix_to_virt(idx);
175 	pte_t *ptep;
176 
177 	BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
178 
179 	ptep = &fixmap_pte[pte_index(addr)];
180 
181 	if (pgprot_val(prot))
182 		set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, prot));
183 	else
184 		pte_clear(&init_mm, addr, ptep);
185 	local_flush_tlb_page(addr);
186 }
187 
188 static inline pte_t *__init get_pte_virt_early(phys_addr_t pa)
189 {
190 	return (pte_t *)((uintptr_t)pa);
191 }
192 
193 static inline pte_t *__init get_pte_virt_fixmap(phys_addr_t pa)
194 {
195 	clear_fixmap(FIX_PTE);
196 	return (pte_t *)set_fixmap_offset(FIX_PTE, pa);
197 }
198 
199 static inline pte_t *get_pte_virt_late(phys_addr_t pa)
200 {
201 	return (pte_t *) __va(pa);
202 }
203 
204 static inline phys_addr_t __init alloc_pte_early(uintptr_t va)
205 {
206 	/*
207 	 * We only create PMD or PGD early mappings so we
208 	 * should never reach here with MMU disabled.
209 	 */
210 	BUG();
211 }
212 
213 static inline phys_addr_t __init alloc_pte_fixmap(uintptr_t va)
214 {
215 	return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
216 }
217 
218 static phys_addr_t alloc_pte_late(uintptr_t va)
219 {
220 	unsigned long vaddr;
221 
222 	vaddr = __get_free_page(GFP_KERNEL);
223 	if (!vaddr || !pgtable_pte_page_ctor(virt_to_page(vaddr)))
224 		BUG();
225 	return __pa(vaddr);
226 }
227 
228 static void __init create_pte_mapping(pte_t *ptep,
229 				      uintptr_t va, phys_addr_t pa,
230 				      phys_addr_t sz, pgprot_t prot)
231 {
232 	uintptr_t pte_idx = pte_index(va);
233 
234 	BUG_ON(sz != PAGE_SIZE);
235 
236 	if (pte_none(ptep[pte_idx]))
237 		ptep[pte_idx] = pfn_pte(PFN_DOWN(pa), prot);
238 }
239 
240 #ifndef __PAGETABLE_PMD_FOLDED
241 
242 pmd_t trampoline_pmd[PTRS_PER_PMD] __page_aligned_bss;
243 pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss;
244 
245 #if MAX_EARLY_MAPPING_SIZE < PGDIR_SIZE
246 #define NUM_EARLY_PMDS		1UL
247 #else
248 #define NUM_EARLY_PMDS		(1UL + MAX_EARLY_MAPPING_SIZE / PGDIR_SIZE)
249 #endif
250 pmd_t early_pmd[PTRS_PER_PMD * NUM_EARLY_PMDS] __initdata __aligned(PAGE_SIZE);
251 pmd_t early_dtb_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);
252 
253 static pmd_t *__init get_pmd_virt_early(phys_addr_t pa)
254 {
255 	/* Before MMU is enabled */
256 	return (pmd_t *)((uintptr_t)pa);
257 }
258 
259 static pmd_t *__init get_pmd_virt_fixmap(phys_addr_t pa)
260 {
261 	clear_fixmap(FIX_PMD);
262 	return (pmd_t *)set_fixmap_offset(FIX_PMD, pa);
263 }
264 
265 static pmd_t *get_pmd_virt_late(phys_addr_t pa)
266 {
267 	return (pmd_t *) __va(pa);
268 }
269 
270 static phys_addr_t __init alloc_pmd_early(uintptr_t va)
271 {
272 	uintptr_t pmd_num;
273 
274 	pmd_num = (va - PAGE_OFFSET) >> PGDIR_SHIFT;
275 	BUG_ON(pmd_num >= NUM_EARLY_PMDS);
276 	return (uintptr_t)&early_pmd[pmd_num * PTRS_PER_PMD];
277 }
278 
279 static phys_addr_t __init alloc_pmd_fixmap(uintptr_t va)
280 {
281 	return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
282 }
283 
284 static phys_addr_t alloc_pmd_late(uintptr_t va)
285 {
286 	unsigned long vaddr;
287 
288 	vaddr = __get_free_page(GFP_KERNEL);
289 	BUG_ON(!vaddr);
290 	return __pa(vaddr);
291 }
292 
293 static void __init create_pmd_mapping(pmd_t *pmdp,
294 				      uintptr_t va, phys_addr_t pa,
295 				      phys_addr_t sz, pgprot_t prot)
296 {
297 	pte_t *ptep;
298 	phys_addr_t pte_phys;
299 	uintptr_t pmd_idx = pmd_index(va);
300 
301 	if (sz == PMD_SIZE) {
302 		if (pmd_none(pmdp[pmd_idx]))
303 			pmdp[pmd_idx] = pfn_pmd(PFN_DOWN(pa), prot);
304 		return;
305 	}
306 
307 	if (pmd_none(pmdp[pmd_idx])) {
308 		pte_phys = pt_ops.alloc_pte(va);
309 		pmdp[pmd_idx] = pfn_pmd(PFN_DOWN(pte_phys), PAGE_TABLE);
310 		ptep = pt_ops.get_pte_virt(pte_phys);
311 		memset(ptep, 0, PAGE_SIZE);
312 	} else {
313 		pte_phys = PFN_PHYS(_pmd_pfn(pmdp[pmd_idx]));
314 		ptep = pt_ops.get_pte_virt(pte_phys);
315 	}
316 
317 	create_pte_mapping(ptep, va, pa, sz, prot);
318 }
319 
320 #define pgd_next_t		pmd_t
321 #define alloc_pgd_next(__va)	pt_ops.alloc_pmd(__va)
322 #define get_pgd_next_virt(__pa)	pt_ops.get_pmd_virt(__pa)
323 #define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot)	\
324 	create_pmd_mapping(__nextp, __va, __pa, __sz, __prot)
325 #define fixmap_pgd_next		fixmap_pmd
326 #else
327 #define pgd_next_t		pte_t
328 #define alloc_pgd_next(__va)	pt_ops.alloc_pte(__va)
329 #define get_pgd_next_virt(__pa)	pt_ops.get_pte_virt(__pa)
330 #define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot)	\
331 	create_pte_mapping(__nextp, __va, __pa, __sz, __prot)
332 #define fixmap_pgd_next		fixmap_pte
333 #endif
334 
335 void __init create_pgd_mapping(pgd_t *pgdp,
336 				      uintptr_t va, phys_addr_t pa,
337 				      phys_addr_t sz, pgprot_t prot)
338 {
339 	pgd_next_t *nextp;
340 	phys_addr_t next_phys;
341 	uintptr_t pgd_idx = pgd_index(va);
342 
343 	if (sz == PGDIR_SIZE) {
344 		if (pgd_val(pgdp[pgd_idx]) == 0)
345 			pgdp[pgd_idx] = pfn_pgd(PFN_DOWN(pa), prot);
346 		return;
347 	}
348 
349 	if (pgd_val(pgdp[pgd_idx]) == 0) {
350 		next_phys = alloc_pgd_next(va);
351 		pgdp[pgd_idx] = pfn_pgd(PFN_DOWN(next_phys), PAGE_TABLE);
352 		nextp = get_pgd_next_virt(next_phys);
353 		memset(nextp, 0, PAGE_SIZE);
354 	} else {
355 		next_phys = PFN_PHYS(_pgd_pfn(pgdp[pgd_idx]));
356 		nextp = get_pgd_next_virt(next_phys);
357 	}
358 
359 	create_pgd_next_mapping(nextp, va, pa, sz, prot);
360 }
361 
362 static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size)
363 {
364 	/* Upgrade to PMD_SIZE mappings whenever possible */
365 	if ((base & (PMD_SIZE - 1)) || (size & (PMD_SIZE - 1)))
366 		return PAGE_SIZE;
367 
368 	return PMD_SIZE;
369 }
370 
371 /*
372  * setup_vm() is called from head.S with MMU-off.
373  *
374  * Following requirements should be honoured for setup_vm() to work
375  * correctly:
376  * 1) It should use PC-relative addressing for accessing kernel symbols.
377  *    To achieve this we always use GCC cmodel=medany.
378  * 2) The compiler instrumentation for FTRACE will not work for setup_vm()
379  *    so disable compiler instrumentation when FTRACE is enabled.
380  *
381  * Currently, the above requirements are honoured by using custom CFLAGS
382  * for init.o in mm/Makefile.
383  */
384 
385 #ifndef __riscv_cmodel_medany
386 #error "setup_vm() is called from head.S before relocate so it should not use absolute addressing."
387 #endif
388 
389 asmlinkage void __init setup_vm(uintptr_t dtb_pa)
390 {
391 	uintptr_t va, pa, end_va;
392 	uintptr_t load_pa = (uintptr_t)(&_start);
393 	uintptr_t load_sz = (uintptr_t)(&_end) - load_pa;
394 	uintptr_t map_size = best_map_size(load_pa, MAX_EARLY_MAPPING_SIZE);
395 #ifndef __PAGETABLE_PMD_FOLDED
396 	pmd_t fix_bmap_spmd, fix_bmap_epmd;
397 #endif
398 
399 	va_pa_offset = PAGE_OFFSET - load_pa;
400 	pfn_base = PFN_DOWN(load_pa);
401 
402 	/*
403 	 * Enforce boot alignment requirements of RV32 and
404 	 * RV64 by only allowing PMD or PGD mappings.
405 	 */
406 	BUG_ON(map_size == PAGE_SIZE);
407 
408 	/* Sanity check alignment and size */
409 	BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
410 	BUG_ON((load_pa % map_size) != 0);
411 	BUG_ON(load_sz > MAX_EARLY_MAPPING_SIZE);
412 
413 	pt_ops.alloc_pte = alloc_pte_early;
414 	pt_ops.get_pte_virt = get_pte_virt_early;
415 #ifndef __PAGETABLE_PMD_FOLDED
416 	pt_ops.alloc_pmd = alloc_pmd_early;
417 	pt_ops.get_pmd_virt = get_pmd_virt_early;
418 #endif
419 	/* Setup early PGD for fixmap */
420 	create_pgd_mapping(early_pg_dir, FIXADDR_START,
421 			   (uintptr_t)fixmap_pgd_next, PGDIR_SIZE, PAGE_TABLE);
422 
423 #ifndef __PAGETABLE_PMD_FOLDED
424 	/* Setup fixmap PMD */
425 	create_pmd_mapping(fixmap_pmd, FIXADDR_START,
426 			   (uintptr_t)fixmap_pte, PMD_SIZE, PAGE_TABLE);
427 	/* Setup trampoline PGD and PMD */
428 	create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET,
429 			   (uintptr_t)trampoline_pmd, PGDIR_SIZE, PAGE_TABLE);
430 	create_pmd_mapping(trampoline_pmd, PAGE_OFFSET,
431 			   load_pa, PMD_SIZE, PAGE_KERNEL_EXEC);
432 #else
433 	/* Setup trampoline PGD */
434 	create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET,
435 			   load_pa, PGDIR_SIZE, PAGE_KERNEL_EXEC);
436 #endif
437 
438 	/*
439 	 * Setup early PGD covering entire kernel which will allows
440 	 * us to reach paging_init(). We map all memory banks later
441 	 * in setup_vm_final() below.
442 	 */
443 	end_va = PAGE_OFFSET + load_sz;
444 	for (va = PAGE_OFFSET; va < end_va; va += map_size)
445 		create_pgd_mapping(early_pg_dir, va,
446 				   load_pa + (va - PAGE_OFFSET),
447 				   map_size, PAGE_KERNEL_EXEC);
448 
449 #ifndef __PAGETABLE_PMD_FOLDED
450 	/* Setup early PMD for DTB */
451 	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA,
452 			   (uintptr_t)early_dtb_pmd, PGDIR_SIZE, PAGE_TABLE);
453 #ifndef CONFIG_BUILTIN_DTB
454 	/* Create two consecutive PMD mappings for FDT early scan */
455 	pa = dtb_pa & ~(PMD_SIZE - 1);
456 	create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA,
457 			   pa, PMD_SIZE, PAGE_KERNEL);
458 	create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA + PMD_SIZE,
459 			   pa + PMD_SIZE, PMD_SIZE, PAGE_KERNEL);
460 	dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PMD_SIZE - 1));
461 #else /* CONFIG_BUILTIN_DTB */
462 	dtb_early_va = __va(dtb_pa);
463 #endif /* CONFIG_BUILTIN_DTB */
464 #else
465 #ifndef CONFIG_BUILTIN_DTB
466 	/* Create two consecutive PGD mappings for FDT early scan */
467 	pa = dtb_pa & ~(PGDIR_SIZE - 1);
468 	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA,
469 			   pa, PGDIR_SIZE, PAGE_KERNEL);
470 	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA + PGDIR_SIZE,
471 			   pa + PGDIR_SIZE, PGDIR_SIZE, PAGE_KERNEL);
472 	dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PGDIR_SIZE - 1));
473 #else /* CONFIG_BUILTIN_DTB */
474 	dtb_early_va = __va(dtb_pa);
475 #endif /* CONFIG_BUILTIN_DTB */
476 #endif
477 	dtb_early_pa = dtb_pa;
478 
479 	/*
480 	 * Bootime fixmap only can handle PMD_SIZE mapping. Thus, boot-ioremap
481 	 * range can not span multiple pmds.
482 	 */
483 	BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
484 		     != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
485 
486 #ifndef __PAGETABLE_PMD_FOLDED
487 	/*
488 	 * Early ioremap fixmap is already created as it lies within first 2MB
489 	 * of fixmap region. We always map PMD_SIZE. Thus, both FIX_BTMAP_END
490 	 * FIX_BTMAP_BEGIN should lie in the same pmd. Verify that and warn
491 	 * the user if not.
492 	 */
493 	fix_bmap_spmd = fixmap_pmd[pmd_index(__fix_to_virt(FIX_BTMAP_BEGIN))];
494 	fix_bmap_epmd = fixmap_pmd[pmd_index(__fix_to_virt(FIX_BTMAP_END))];
495 	if (pmd_val(fix_bmap_spmd) != pmd_val(fix_bmap_epmd)) {
496 		WARN_ON(1);
497 		pr_warn("fixmap btmap start [%08lx] != end [%08lx]\n",
498 			pmd_val(fix_bmap_spmd), pmd_val(fix_bmap_epmd));
499 		pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
500 			fix_to_virt(FIX_BTMAP_BEGIN));
501 		pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
502 			fix_to_virt(FIX_BTMAP_END));
503 
504 		pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
505 		pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
506 	}
507 #endif
508 }
509 
510 static void __init setup_vm_final(void)
511 {
512 	uintptr_t va, map_size;
513 	phys_addr_t pa, start, end;
514 	u64 i;
515 
516 	/**
517 	 * MMU is enabled at this point. But page table setup is not complete yet.
518 	 * fixmap page table alloc functions should be used at this point
519 	 */
520 	pt_ops.alloc_pte = alloc_pte_fixmap;
521 	pt_ops.get_pte_virt = get_pte_virt_fixmap;
522 #ifndef __PAGETABLE_PMD_FOLDED
523 	pt_ops.alloc_pmd = alloc_pmd_fixmap;
524 	pt_ops.get_pmd_virt = get_pmd_virt_fixmap;
525 #endif
526 	/* Setup swapper PGD for fixmap */
527 	create_pgd_mapping(swapper_pg_dir, FIXADDR_START,
528 			   __pa_symbol(fixmap_pgd_next),
529 			   PGDIR_SIZE, PAGE_TABLE);
530 
531 	/* Map all memory banks */
532 	for_each_mem_range(i, &start, &end) {
533 		if (start >= end)
534 			break;
535 		if (start <= __pa(PAGE_OFFSET) &&
536 		    __pa(PAGE_OFFSET) < end)
537 			start = __pa(PAGE_OFFSET);
538 
539 		map_size = best_map_size(start, end - start);
540 		for (pa = start; pa < end; pa += map_size) {
541 			va = (uintptr_t)__va(pa);
542 			create_pgd_mapping(swapper_pg_dir, va, pa,
543 					   map_size, PAGE_KERNEL_EXEC);
544 		}
545 	}
546 
547 	/* Clear fixmap PTE and PMD mappings */
548 	clear_fixmap(FIX_PTE);
549 	clear_fixmap(FIX_PMD);
550 
551 	/* Move to swapper page table */
552 	csr_write(CSR_SATP, PFN_DOWN(__pa_symbol(swapper_pg_dir)) | SATP_MODE);
553 	local_flush_tlb_all();
554 
555 	/* generic page allocation functions must be used to setup page table */
556 	pt_ops.alloc_pte = alloc_pte_late;
557 	pt_ops.get_pte_virt = get_pte_virt_late;
558 #ifndef __PAGETABLE_PMD_FOLDED
559 	pt_ops.alloc_pmd = alloc_pmd_late;
560 	pt_ops.get_pmd_virt = get_pmd_virt_late;
561 #endif
562 }
563 #else
564 asmlinkage void __init setup_vm(uintptr_t dtb_pa)
565 {
566 	dtb_early_va = (void *)dtb_pa;
567 	dtb_early_pa = dtb_pa;
568 }
569 
570 static inline void setup_vm_final(void)
571 {
572 }
573 #endif /* CONFIG_MMU */
574 
575 #ifdef CONFIG_STRICT_KERNEL_RWX
576 void protect_kernel_text_data(void)
577 {
578 	unsigned long text_start = (unsigned long)_start;
579 	unsigned long init_text_start = (unsigned long)__init_text_begin;
580 	unsigned long init_data_start = (unsigned long)__init_data_begin;
581 	unsigned long rodata_start = (unsigned long)__start_rodata;
582 	unsigned long data_start = (unsigned long)_data;
583 	unsigned long max_low = (unsigned long)(__va(PFN_PHYS(max_low_pfn)));
584 
585 	set_memory_ro(text_start, (init_text_start - text_start) >> PAGE_SHIFT);
586 	set_memory_ro(init_text_start, (init_data_start - init_text_start) >> PAGE_SHIFT);
587 	set_memory_nx(init_data_start, (rodata_start - init_data_start) >> PAGE_SHIFT);
588 	/* rodata section is marked readonly in mark_rodata_ro */
589 	set_memory_nx(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
590 	set_memory_nx(data_start, (max_low - data_start) >> PAGE_SHIFT);
591 }
592 
593 void mark_rodata_ro(void)
594 {
595 	unsigned long rodata_start = (unsigned long)__start_rodata;
596 	unsigned long data_start = (unsigned long)_data;
597 
598 	set_memory_ro(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
599 
600 	debug_checkwx();
601 }
602 #endif
603 
604 void __init paging_init(void)
605 {
606 	setup_vm_final();
607 	setup_zero_page();
608 }
609 
610 void __init misc_mem_init(void)
611 {
612 	arch_numa_init();
613 	sparse_init();
614 	zone_sizes_init();
615 	memblock_dump_all();
616 }
617 
618 #ifdef CONFIG_SPARSEMEM_VMEMMAP
619 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
620 			       struct vmem_altmap *altmap)
621 {
622 	return vmemmap_populate_basepages(start, end, node, NULL);
623 }
624 #endif
625