xref: /linux/arch/riscv/mm/init.c (revision 8b83369ddcb3fb9cab5c1088987ce477565bb630)
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, dram_end, end = 0;
113 	phys_addr_t vmlinux_end = __pa_symbol(&_end);
114 	phys_addr_t vmlinux_start = __pa_symbol(&_start);
115 	phys_addr_t max_mapped_addr = __pa(~(ulong)0);
116 	u64 i;
117 
118 	/* Find the memory region containing the kernel */
119 	for_each_mem_range(i, &start, &end) {
120 		phys_addr_t size = end - start;
121 		if (!mem_start)
122 			mem_start = start;
123 		if (start <= vmlinux_start && vmlinux_end <= end)
124 			BUG_ON(size == 0);
125 	}
126 
127 	/*
128 	 * The maximal physical memory size is -PAGE_OFFSET.
129 	 * Make sure that any memory beyond mem_start + (-PAGE_OFFSET) is removed
130 	 * as it is unusable by kernel.
131 	 */
132 	memblock_enforce_memory_limit(-PAGE_OFFSET);
133 
134 	/* Reserve from the start of the kernel to the end of the kernel */
135 	memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
136 
137 	dram_end = memblock_end_of_DRAM();
138 
139 	/*
140 	 * memblock allocator is not aware of the fact that last 4K bytes of
141 	 * the addressable memory can not be mapped because of IS_ERR_VALUE
142 	 * macro. Make sure that last 4k bytes are not usable by memblock
143 	 * if end of dram is equal to maximum addressable memory.
144 	 */
145 	if (max_mapped_addr == (dram_end - 1))
146 		memblock_set_current_limit(max_mapped_addr - 4096);
147 
148 	max_pfn = PFN_DOWN(dram_end);
149 	max_low_pfn = max_pfn;
150 	dma32_phys_limit = min(4UL * SZ_1G, (unsigned long)PFN_PHYS(max_low_pfn));
151 	set_max_mapnr(max_low_pfn - ARCH_PFN_OFFSET);
152 
153 	reserve_initrd_mem();
154 	/*
155 	 * If DTB is built in, no need to reserve its memblock.
156 	 * Otherwise, do reserve it but avoid using
157 	 * early_init_fdt_reserve_self() since __pa() does
158 	 * not work for DTB pointers that are fixmap addresses
159 	 */
160 	if (!IS_ENABLED(CONFIG_BUILTIN_DTB))
161 		memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));
162 
163 	early_init_fdt_scan_reserved_mem();
164 	dma_contiguous_reserve(dma32_phys_limit);
165 	memblock_allow_resize();
166 }
167 
168 #ifdef CONFIG_MMU
169 static struct pt_alloc_ops pt_ops;
170 
171 unsigned long va_pa_offset;
172 EXPORT_SYMBOL(va_pa_offset);
173 unsigned long pfn_base;
174 EXPORT_SYMBOL(pfn_base);
175 
176 pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
177 pgd_t trampoline_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
178 pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss;
179 
180 pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
181 
182 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot)
183 {
184 	unsigned long addr = __fix_to_virt(idx);
185 	pte_t *ptep;
186 
187 	BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
188 
189 	ptep = &fixmap_pte[pte_index(addr)];
190 
191 	if (pgprot_val(prot))
192 		set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, prot));
193 	else
194 		pte_clear(&init_mm, addr, ptep);
195 	local_flush_tlb_page(addr);
196 }
197 
198 static inline pte_t *__init get_pte_virt_early(phys_addr_t pa)
199 {
200 	return (pte_t *)((uintptr_t)pa);
201 }
202 
203 static inline pte_t *__init get_pte_virt_fixmap(phys_addr_t pa)
204 {
205 	clear_fixmap(FIX_PTE);
206 	return (pte_t *)set_fixmap_offset(FIX_PTE, pa);
207 }
208 
209 static inline pte_t *get_pte_virt_late(phys_addr_t pa)
210 {
211 	return (pte_t *) __va(pa);
212 }
213 
214 static inline phys_addr_t __init alloc_pte_early(uintptr_t va)
215 {
216 	/*
217 	 * We only create PMD or PGD early mappings so we
218 	 * should never reach here with MMU disabled.
219 	 */
220 	BUG();
221 }
222 
223 static inline phys_addr_t __init alloc_pte_fixmap(uintptr_t va)
224 {
225 	return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
226 }
227 
228 static phys_addr_t alloc_pte_late(uintptr_t va)
229 {
230 	unsigned long vaddr;
231 
232 	vaddr = __get_free_page(GFP_KERNEL);
233 	if (!vaddr || !pgtable_pte_page_ctor(virt_to_page(vaddr)))
234 		BUG();
235 	return __pa(vaddr);
236 }
237 
238 static void __init create_pte_mapping(pte_t *ptep,
239 				      uintptr_t va, phys_addr_t pa,
240 				      phys_addr_t sz, pgprot_t prot)
241 {
242 	uintptr_t pte_idx = pte_index(va);
243 
244 	BUG_ON(sz != PAGE_SIZE);
245 
246 	if (pte_none(ptep[pte_idx]))
247 		ptep[pte_idx] = pfn_pte(PFN_DOWN(pa), prot);
248 }
249 
250 #ifndef __PAGETABLE_PMD_FOLDED
251 
252 pmd_t trampoline_pmd[PTRS_PER_PMD] __page_aligned_bss;
253 pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss;
254 pmd_t early_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);
255 pmd_t early_dtb_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);
256 
257 static pmd_t *__init get_pmd_virt_early(phys_addr_t pa)
258 {
259 	/* Before MMU is enabled */
260 	return (pmd_t *)((uintptr_t)pa);
261 }
262 
263 static pmd_t *__init get_pmd_virt_fixmap(phys_addr_t pa)
264 {
265 	clear_fixmap(FIX_PMD);
266 	return (pmd_t *)set_fixmap_offset(FIX_PMD, pa);
267 }
268 
269 static pmd_t *get_pmd_virt_late(phys_addr_t pa)
270 {
271 	return (pmd_t *) __va(pa);
272 }
273 
274 static phys_addr_t __init alloc_pmd_early(uintptr_t va)
275 {
276 	BUG_ON((va - PAGE_OFFSET) >> PGDIR_SHIFT);
277 
278 	return (uintptr_t)early_pmd;
279 }
280 
281 static phys_addr_t __init alloc_pmd_fixmap(uintptr_t va)
282 {
283 	return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
284 }
285 
286 static phys_addr_t alloc_pmd_late(uintptr_t va)
287 {
288 	unsigned long vaddr;
289 
290 	vaddr = __get_free_page(GFP_KERNEL);
291 	BUG_ON(!vaddr);
292 	return __pa(vaddr);
293 }
294 
295 static void __init create_pmd_mapping(pmd_t *pmdp,
296 				      uintptr_t va, phys_addr_t pa,
297 				      phys_addr_t sz, pgprot_t prot)
298 {
299 	pte_t *ptep;
300 	phys_addr_t pte_phys;
301 	uintptr_t pmd_idx = pmd_index(va);
302 
303 	if (sz == PMD_SIZE) {
304 		if (pmd_none(pmdp[pmd_idx]))
305 			pmdp[pmd_idx] = pfn_pmd(PFN_DOWN(pa), prot);
306 		return;
307 	}
308 
309 	if (pmd_none(pmdp[pmd_idx])) {
310 		pte_phys = pt_ops.alloc_pte(va);
311 		pmdp[pmd_idx] = pfn_pmd(PFN_DOWN(pte_phys), PAGE_TABLE);
312 		ptep = pt_ops.get_pte_virt(pte_phys);
313 		memset(ptep, 0, PAGE_SIZE);
314 	} else {
315 		pte_phys = PFN_PHYS(_pmd_pfn(pmdp[pmd_idx]));
316 		ptep = pt_ops.get_pte_virt(pte_phys);
317 	}
318 
319 	create_pte_mapping(ptep, va, pa, sz, prot);
320 }
321 
322 #define pgd_next_t		pmd_t
323 #define alloc_pgd_next(__va)	pt_ops.alloc_pmd(__va)
324 #define get_pgd_next_virt(__pa)	pt_ops.get_pmd_virt(__pa)
325 #define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot)	\
326 	create_pmd_mapping(__nextp, __va, __pa, __sz, __prot)
327 #define fixmap_pgd_next		fixmap_pmd
328 #else
329 #define pgd_next_t		pte_t
330 #define alloc_pgd_next(__va)	pt_ops.alloc_pte(__va)
331 #define get_pgd_next_virt(__pa)	pt_ops.get_pte_virt(__pa)
332 #define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot)	\
333 	create_pte_mapping(__nextp, __va, __pa, __sz, __prot)
334 #define fixmap_pgd_next		fixmap_pte
335 #endif
336 
337 void __init create_pgd_mapping(pgd_t *pgdp,
338 				      uintptr_t va, phys_addr_t pa,
339 				      phys_addr_t sz, pgprot_t prot)
340 {
341 	pgd_next_t *nextp;
342 	phys_addr_t next_phys;
343 	uintptr_t pgd_idx = pgd_index(va);
344 
345 	if (sz == PGDIR_SIZE) {
346 		if (pgd_val(pgdp[pgd_idx]) == 0)
347 			pgdp[pgd_idx] = pfn_pgd(PFN_DOWN(pa), prot);
348 		return;
349 	}
350 
351 	if (pgd_val(pgdp[pgd_idx]) == 0) {
352 		next_phys = alloc_pgd_next(va);
353 		pgdp[pgd_idx] = pfn_pgd(PFN_DOWN(next_phys), PAGE_TABLE);
354 		nextp = get_pgd_next_virt(next_phys);
355 		memset(nextp, 0, PAGE_SIZE);
356 	} else {
357 		next_phys = PFN_PHYS(_pgd_pfn(pgdp[pgd_idx]));
358 		nextp = get_pgd_next_virt(next_phys);
359 	}
360 
361 	create_pgd_next_mapping(nextp, va, pa, sz, prot);
362 }
363 
364 static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size)
365 {
366 	/* Upgrade to PMD_SIZE mappings whenever possible */
367 	if ((base & (PMD_SIZE - 1)) || (size & (PMD_SIZE - 1)))
368 		return PAGE_SIZE;
369 
370 	return PMD_SIZE;
371 }
372 
373 /*
374  * setup_vm() is called from head.S with MMU-off.
375  *
376  * Following requirements should be honoured for setup_vm() to work
377  * correctly:
378  * 1) It should use PC-relative addressing for accessing kernel symbols.
379  *    To achieve this we always use GCC cmodel=medany.
380  * 2) The compiler instrumentation for FTRACE will not work for setup_vm()
381  *    so disable compiler instrumentation when FTRACE is enabled.
382  *
383  * Currently, the above requirements are honoured by using custom CFLAGS
384  * for init.o in mm/Makefile.
385  */
386 
387 #ifndef __riscv_cmodel_medany
388 #error "setup_vm() is called from head.S before relocate so it should not use absolute addressing."
389 #endif
390 
391 asmlinkage void __init setup_vm(uintptr_t dtb_pa)
392 {
393 	uintptr_t va, pa, end_va;
394 	uintptr_t load_pa = (uintptr_t)(&_start);
395 	uintptr_t load_sz = (uintptr_t)(&_end) - load_pa;
396 	uintptr_t map_size;
397 #ifndef __PAGETABLE_PMD_FOLDED
398 	pmd_t fix_bmap_spmd, fix_bmap_epmd;
399 #endif
400 
401 	va_pa_offset = PAGE_OFFSET - load_pa;
402 	pfn_base = PFN_DOWN(load_pa);
403 
404 	/*
405 	 * Enforce boot alignment requirements of RV32 and
406 	 * RV64 by only allowing PMD or PGD mappings.
407 	 */
408 	map_size = PMD_SIZE;
409 
410 	/* Sanity check alignment and size */
411 	BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
412 	BUG_ON((load_pa % map_size) != 0);
413 
414 	pt_ops.alloc_pte = alloc_pte_early;
415 	pt_ops.get_pte_virt = get_pte_virt_early;
416 #ifndef __PAGETABLE_PMD_FOLDED
417 	pt_ops.alloc_pmd = alloc_pmd_early;
418 	pt_ops.get_pmd_virt = get_pmd_virt_early;
419 #endif
420 	/* Setup early PGD for fixmap */
421 	create_pgd_mapping(early_pg_dir, FIXADDR_START,
422 			   (uintptr_t)fixmap_pgd_next, PGDIR_SIZE, PAGE_TABLE);
423 
424 #ifndef __PAGETABLE_PMD_FOLDED
425 	/* Setup fixmap PMD */
426 	create_pmd_mapping(fixmap_pmd, FIXADDR_START,
427 			   (uintptr_t)fixmap_pte, PMD_SIZE, PAGE_TABLE);
428 	/* Setup trampoline PGD and PMD */
429 	create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET,
430 			   (uintptr_t)trampoline_pmd, PGDIR_SIZE, PAGE_TABLE);
431 	create_pmd_mapping(trampoline_pmd, PAGE_OFFSET,
432 			   load_pa, PMD_SIZE, PAGE_KERNEL_EXEC);
433 #else
434 	/* Setup trampoline PGD */
435 	create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET,
436 			   load_pa, PGDIR_SIZE, PAGE_KERNEL_EXEC);
437 #endif
438 
439 	/*
440 	 * Setup early PGD covering entire kernel which will allows
441 	 * us to reach paging_init(). We map all memory banks later
442 	 * in setup_vm_final() below.
443 	 */
444 	end_va = PAGE_OFFSET + load_sz;
445 	for (va = PAGE_OFFSET; va < end_va; va += map_size)
446 		create_pgd_mapping(early_pg_dir, va,
447 				   load_pa + (va - PAGE_OFFSET),
448 				   map_size, PAGE_KERNEL_EXEC);
449 
450 #ifndef __PAGETABLE_PMD_FOLDED
451 	/* Setup early PMD for DTB */
452 	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA,
453 			   (uintptr_t)early_dtb_pmd, PGDIR_SIZE, PAGE_TABLE);
454 #ifndef CONFIG_BUILTIN_DTB
455 	/* Create two consecutive PMD mappings for FDT early scan */
456 	pa = dtb_pa & ~(PMD_SIZE - 1);
457 	create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA,
458 			   pa, PMD_SIZE, PAGE_KERNEL);
459 	create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA + PMD_SIZE,
460 			   pa + PMD_SIZE, PMD_SIZE, PAGE_KERNEL);
461 	dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PMD_SIZE - 1));
462 #else /* CONFIG_BUILTIN_DTB */
463 	dtb_early_va = __va(dtb_pa);
464 #endif /* CONFIG_BUILTIN_DTB */
465 #else
466 #ifndef CONFIG_BUILTIN_DTB
467 	/* Create two consecutive PGD mappings for FDT early scan */
468 	pa = dtb_pa & ~(PGDIR_SIZE - 1);
469 	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA,
470 			   pa, PGDIR_SIZE, PAGE_KERNEL);
471 	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA + PGDIR_SIZE,
472 			   pa + PGDIR_SIZE, PGDIR_SIZE, PAGE_KERNEL);
473 	dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PGDIR_SIZE - 1));
474 #else /* CONFIG_BUILTIN_DTB */
475 	dtb_early_va = __va(dtb_pa);
476 #endif /* CONFIG_BUILTIN_DTB */
477 #endif
478 	dtb_early_pa = dtb_pa;
479 
480 	/*
481 	 * Bootime fixmap only can handle PMD_SIZE mapping. Thus, boot-ioremap
482 	 * range can not span multiple pmds.
483 	 */
484 	BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
485 		     != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
486 
487 #ifndef __PAGETABLE_PMD_FOLDED
488 	/*
489 	 * Early ioremap fixmap is already created as it lies within first 2MB
490 	 * of fixmap region. We always map PMD_SIZE. Thus, both FIX_BTMAP_END
491 	 * FIX_BTMAP_BEGIN should lie in the same pmd. Verify that and warn
492 	 * the user if not.
493 	 */
494 	fix_bmap_spmd = fixmap_pmd[pmd_index(__fix_to_virt(FIX_BTMAP_BEGIN))];
495 	fix_bmap_epmd = fixmap_pmd[pmd_index(__fix_to_virt(FIX_BTMAP_END))];
496 	if (pmd_val(fix_bmap_spmd) != pmd_val(fix_bmap_epmd)) {
497 		WARN_ON(1);
498 		pr_warn("fixmap btmap start [%08lx] != end [%08lx]\n",
499 			pmd_val(fix_bmap_spmd), pmd_val(fix_bmap_epmd));
500 		pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
501 			fix_to_virt(FIX_BTMAP_BEGIN));
502 		pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
503 			fix_to_virt(FIX_BTMAP_END));
504 
505 		pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
506 		pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
507 	}
508 #endif
509 }
510 
511 static void __init setup_vm_final(void)
512 {
513 	uintptr_t va, map_size;
514 	phys_addr_t pa, start, end;
515 	u64 i;
516 
517 	/**
518 	 * MMU is enabled at this point. But page table setup is not complete yet.
519 	 * fixmap page table alloc functions should be used at this point
520 	 */
521 	pt_ops.alloc_pte = alloc_pte_fixmap;
522 	pt_ops.get_pte_virt = get_pte_virt_fixmap;
523 #ifndef __PAGETABLE_PMD_FOLDED
524 	pt_ops.alloc_pmd = alloc_pmd_fixmap;
525 	pt_ops.get_pmd_virt = get_pmd_virt_fixmap;
526 #endif
527 	/* Setup swapper PGD for fixmap */
528 	create_pgd_mapping(swapper_pg_dir, FIXADDR_START,
529 			   __pa_symbol(fixmap_pgd_next),
530 			   PGDIR_SIZE, PAGE_TABLE);
531 
532 	/* Map all memory banks */
533 	for_each_mem_range(i, &start, &end) {
534 		if (start >= end)
535 			break;
536 		if (start <= __pa(PAGE_OFFSET) &&
537 		    __pa(PAGE_OFFSET) < end)
538 			start = __pa(PAGE_OFFSET);
539 
540 		map_size = best_map_size(start, end - start);
541 		for (pa = start; pa < end; pa += map_size) {
542 			va = (uintptr_t)__va(pa);
543 			create_pgd_mapping(swapper_pg_dir, va, pa,
544 					   map_size, PAGE_KERNEL_EXEC);
545 		}
546 	}
547 
548 	/* Clear fixmap PTE and PMD mappings */
549 	clear_fixmap(FIX_PTE);
550 	clear_fixmap(FIX_PMD);
551 
552 	/* Move to swapper page table */
553 	csr_write(CSR_SATP, PFN_DOWN(__pa_symbol(swapper_pg_dir)) | SATP_MODE);
554 	local_flush_tlb_all();
555 
556 	/* generic page allocation functions must be used to setup page table */
557 	pt_ops.alloc_pte = alloc_pte_late;
558 	pt_ops.get_pte_virt = get_pte_virt_late;
559 #ifndef __PAGETABLE_PMD_FOLDED
560 	pt_ops.alloc_pmd = alloc_pmd_late;
561 	pt_ops.get_pmd_virt = get_pmd_virt_late;
562 #endif
563 }
564 #else
565 asmlinkage void __init setup_vm(uintptr_t dtb_pa)
566 {
567 	dtb_early_va = (void *)dtb_pa;
568 	dtb_early_pa = dtb_pa;
569 }
570 
571 static inline void setup_vm_final(void)
572 {
573 }
574 #endif /* CONFIG_MMU */
575 
576 #ifdef CONFIG_STRICT_KERNEL_RWX
577 void protect_kernel_text_data(void)
578 {
579 	unsigned long text_start = (unsigned long)_start;
580 	unsigned long init_text_start = (unsigned long)__init_text_begin;
581 	unsigned long init_data_start = (unsigned long)__init_data_begin;
582 	unsigned long rodata_start = (unsigned long)__start_rodata;
583 	unsigned long data_start = (unsigned long)_data;
584 	unsigned long max_low = (unsigned long)(__va(PFN_PHYS(max_low_pfn)));
585 
586 	set_memory_ro(text_start, (init_text_start - text_start) >> PAGE_SHIFT);
587 	set_memory_ro(init_text_start, (init_data_start - init_text_start) >> PAGE_SHIFT);
588 	set_memory_nx(init_data_start, (rodata_start - init_data_start) >> PAGE_SHIFT);
589 	/* rodata section is marked readonly in mark_rodata_ro */
590 	set_memory_nx(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
591 	set_memory_nx(data_start, (max_low - data_start) >> PAGE_SHIFT);
592 }
593 
594 void mark_rodata_ro(void)
595 {
596 	unsigned long rodata_start = (unsigned long)__start_rodata;
597 	unsigned long data_start = (unsigned long)_data;
598 
599 	set_memory_ro(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
600 
601 	debug_checkwx();
602 }
603 #endif
604 
605 void __init paging_init(void)
606 {
607 	setup_vm_final();
608 	setup_zero_page();
609 }
610 
611 void __init misc_mem_init(void)
612 {
613 	arch_numa_init();
614 	sparse_init();
615 	zone_sizes_init();
616 	memblock_dump_all();
617 }
618 
619 #ifdef CONFIG_SPARSEMEM_VMEMMAP
620 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
621 			       struct vmem_altmap *altmap)
622 {
623 	return vmemmap_populate_basepages(start, end, node, NULL);
624 }
625 #endif
626