init.c

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