// SPDX-License-Identifier: GPL-2.0/* * Virtual Memory Map support * * (C) 2007 sgi. Christoph Lameter. * * Virtual memory maps allow VM primitives pfn_to_page, page_to_pfn, * virt_to_page, page_address() to be implemented as a base offset * calculation without memory access. * * However, virtual mappings need a page table and TLBs. Many Linux * architectures already map their physical space using 1-1 mappings * via TLBs. For those arches the virtual memory map is essentially * for free if we use the same page size as the 1-1 mappings. In that * case the overhead consists of a few additional pages that are * allocated to create a view of memory for vmemmap. * * The architecture is expected to provide a vmemmap_populate() function * to instantiate the mapping. */#include <linux/mm.h>#include <linux/mmzone.h>#include <linux/memblock.h>#include <linux/memremap.h>#include <linux/highmem.h>#include <linux/slab.h>#include <linux/spinlock.h>#include <linux/vmalloc.h>#include <linux/sched.h>#include <linux/pgalloc.h> #include <asm/dma.h>#include <asm/tlbflush.h> #include "hugetlb_vmemmap.h" /* * Flags for vmemmap_populate_range and friends. *//* Get a ref on the head page struct page, for ZONE_DEVICE compound pages */#define VMEMMAP_POPULATE_PAGEREF	0x0001 #include "internal.h"#include "mm_init.h"#include "sparse.h" /* * Allocate a block of memory to be used to back the virtual memory map * or to back the page tables that are used to create the mapping. * Uses the main allocators if they are available, else bootmem. */ static void * __ref __earlyonly_bootmem_alloc(int node,				unsigned long size,				unsigned long align,				unsigned long goal){	return memmap_alloc(size, align, goal, node, false);} void * __meminit vmemmap_alloc_block(unsigned long size, int node){	/* If the main allocator is up use that, fallback to bootmem. */	if (slab_is_available()) {		gfp_t gfp_mask = GFP_KERNEL|__GFP_RETRY_MAYFAIL|__GFP_NOWARN;		int order = get_order(size);		static bool warned __meminitdata;		struct page *page; 		page = alloc_pages_node(node, gfp_mask, order);		if (page)			return page_address(page); 		if (!warned) {			warn_alloc(gfp_mask & ~__GFP_NOWARN, NULL,				   "vmemmap alloc failure: order:%u", order);			warned = true;		}		return NULL;	} else		return __earlyonly_bootmem_alloc(node, size, size,				__pa(MAX_DMA_ADDRESS));} static void * __meminit altmap_alloc_block_buf(unsigned long size,					       struct vmem_altmap *altmap); /* need to make sure size is all the same during early stage */void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node,					 struct vmem_altmap *altmap){	if (altmap)		return altmap_alloc_block_buf(size, altmap); 	return vmemmap_alloc_block(size, node);} static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap){	return altmap->base_pfn + altmap->reserve + altmap->alloc		+ altmap->align;} static unsigned long __meminit vmem_altmap_nr_free(struct vmem_altmap *altmap){	unsigned long allocated = altmap->alloc + altmap->align; 	if (altmap->free > allocated)		return altmap->free - allocated;	return 0;} static void * __meminit altmap_alloc_block_buf(unsigned long size,					       struct vmem_altmap *altmap){	unsigned long pfn, nr_pfns, nr_align; 	if (size & ~PAGE_MASK) {		pr_warn_once("%s: allocations must be multiple of PAGE_SIZE (%ld)\n",				__func__, size);		return NULL;	} 	pfn = vmem_altmap_next_pfn(altmap);	nr_pfns = size >> PAGE_SHIFT;	nr_align = 1UL << find_first_bit(&nr_pfns, BITS_PER_LONG);	nr_align = ALIGN(pfn, nr_align) - pfn;	if (nr_pfns + nr_align > vmem_altmap_nr_free(altmap))		return NULL; 	altmap->alloc += nr_pfns;	altmap->align += nr_align;	pfn += nr_align; 	pr_debug("%s: pfn: %#lx alloc: %ld align: %ld nr: %#lx\n",			__func__, pfn, altmap->alloc, altmap->align, nr_pfns);	return __va(__pfn_to_phys(pfn));} void __meminit vmemmap_verify(pte_t *pte, int node,				unsigned long start, unsigned long end){	unsigned long pfn = pte_pfn(ptep_get(pte));	int actual_node = early_pfn_to_nid(pfn); 	if (node_distance(actual_node, node) > LOCAL_DISTANCE)		pr_warn_once("[%lx-%lx] potential offnode page_structs\n",			start, end - 1);} static pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node,				       struct vmem_altmap *altmap,				       unsigned long ptpfn, unsigned long flags){	pte_t *pte = pte_offset_kernel(pmd, addr);	if (pte_none(ptep_get(pte))) {		pte_t entry;		void *p; 		if (ptpfn == (unsigned long)-1) {			p = vmemmap_alloc_block_buf(PAGE_SIZE, node, altmap);			if (!p)				return NULL;			ptpfn = PHYS_PFN(__pa(p));		} else {			/*			 * When a PTE/PMD entry is freed from the init_mm			 * there's a free_pages() call to this page allocated			 * above. Thus this get_page() is paired with the			 * put_page_testzero() on the freeing path.			 * This can only called by certain ZONE_DEVICE path,			 * and through vmemmap_populate_compound_pages() when			 * slab is available.			 */			if (flags & VMEMMAP_POPULATE_PAGEREF)				get_page(pfn_to_page(ptpfn));		}		entry = pfn_pte(ptpfn, PAGE_KERNEL);		set_pte_at(&init_mm, addr, pte, entry);	}	return pte;} static void * __meminit vmemmap_alloc_block_zero(unsigned long size, int node){	void *p = vmemmap_alloc_block(size, node); 	if (!p)		return NULL;	memset(p, 0, size); 	return p;} static pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node){	pmd_t *pmd = pmd_offset(pud, addr);	if (pmd_none(*pmd)) {		void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);		if (!p)			return NULL;		kernel_pte_init(p);		pmd_populate_kernel(&init_mm, pmd, p);	}	return pmd;} static pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node){	pud_t *pud = pud_offset(p4d, addr);	if (pud_none(*pud)) {		void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);		if (!p)			return NULL;		pmd_init(p);		pud_populate(&init_mm, pud, p);	}	return pud;} static p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node){	p4d_t *p4d = p4d_offset(pgd, addr);	if (p4d_none(*p4d)) {		void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);		if (!p)			return NULL;		pud_init(p);		p4d_populate_kernel(addr, p4d, p);	}	return p4d;} static pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node){	pgd_t *pgd = pgd_offset_k(addr);	if (pgd_none(*pgd)) {		void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);		if (!p)			return NULL;		pgd_populate_kernel(addr, pgd, p);	}	return pgd;} static pte_t * __meminit vmemmap_populate_address(unsigned long addr, int node,					      struct vmem_altmap *altmap,					      unsigned long ptpfn,					      unsigned long flags){	pgd_t *pgd;	p4d_t *p4d;	pud_t *pud;	pmd_t *pmd;	pte_t *pte; 	pgd = vmemmap_pgd_populate(addr, node);	if (!pgd)		return NULL;	p4d = vmemmap_p4d_populate(pgd, addr, node);	if (!p4d)		return NULL;	pud = vmemmap_pud_populate(p4d, addr, node);	if (!pud)		return NULL;	pmd = vmemmap_pmd_populate(pud, addr, node);	if (!pmd)		return NULL;	pte = vmemmap_pte_populate(pmd, addr, node, altmap, ptpfn, flags);	if (!pte)		return NULL;	vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); 	return pte;} static int __meminit vmemmap_populate_range(unsigned long start,					    unsigned long end, int node,					    struct vmem_altmap *altmap,					    unsigned long ptpfn,					    unsigned long flags){	unsigned long addr = start;	pte_t *pte; 	for (; addr < end; addr += PAGE_SIZE) {		pte = vmemmap_populate_address(addr, node, altmap,					       ptpfn, flags);		if (!pte)			return -ENOMEM;	} 	return 0;} int __meminit vmemmap_populate_basepages(unsigned long start, unsigned long end,					 int node, struct vmem_altmap *altmap){	return vmemmap_populate_range(start, end, node, altmap, -1, 0);} /* * Write protect the mirrored tail page structs for HVO. This will be * called from the hugetlb code when gathering and initializing the * memblock allocated gigantic pages. The write protect can't be * done earlier, since it can't be guaranteed that the reserved * page structures will not be written to during initialization, * even if CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled. * * The PTEs are known to exist, and nothing else should be touching * these pages. The caller is responsible for any TLB flushing. */void vmemmap_wrprotect_hvo(unsigned long addr, unsigned long end,				    int node, unsigned long headsize){	unsigned long maddr;	pte_t *pte; 	for (maddr = addr + headsize; maddr < end; maddr += PAGE_SIZE) {		pte = virt_to_kpte(maddr);		ptep_set_wrprotect(&init_mm, maddr, pte);	}} #ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAPstatic __meminit struct page *vmemmap_get_tail(unsigned int order, struct zone *zone){	struct page *p, *tail;	unsigned int idx;	int node = zone_to_nid(zone); 	if (WARN_ON_ONCE(order < VMEMMAP_TAIL_MIN_ORDER))		return NULL;	if (WARN_ON_ONCE(order > MAX_FOLIO_ORDER))		return NULL; 	idx = order - VMEMMAP_TAIL_MIN_ORDER;	tail = zone->vmemmap_tails[idx];	if (tail)		return tail; 	/*	 * Only allocate the page, but do not initialize it.	 *	 * Any initialization done here will be overwritten by memmap_init().	 *	 * hugetlb_bootmem_struct_page_init() will take care of initialization	 * after memmap_init().	 */ 	p = vmemmap_alloc_block_zero(PAGE_SIZE, node);	if (!p)		return NULL; 	tail = virt_to_page(p);	zone->vmemmap_tails[idx] = tail; 	return tail;} int __meminit vmemmap_populate_hvo(unsigned long addr, unsigned long end,				       unsigned int order, struct zone *zone,				       unsigned long headsize){	unsigned long maddr;	struct page *tail;	pte_t *pte;	int node = zone_to_nid(zone); 	tail = vmemmap_get_tail(order, zone);	if (!tail)		return -ENOMEM; 	for (maddr = addr; maddr < addr + headsize; maddr += PAGE_SIZE) {		pte = vmemmap_populate_address(maddr, node, NULL, -1, 0);		if (!pte)			return -ENOMEM;	} 	/*	 * Reuse the last page struct page mapped above for the rest.	 */	return vmemmap_populate_range(maddr, end, node, NULL,				      page_to_pfn(tail), 0);}#endif void __weak __meminit vmemmap_set_pmd(pmd_t *pmd, void *p, int node,				      unsigned long addr, unsigned long next){	WARN_ON_ONCE(!pmd_set_huge(pmd, virt_to_phys(p), PAGE_KERNEL));} int __weak __meminit vmemmap_check_pmd(pmd_t *pmd, int node,				       unsigned long addr, unsigned long next){	if (!pmd_leaf(pmdp_get(pmd)))		return 0;	vmemmap_verify((pte_t *)pmd, node, addr, next); 	return 1;} int __meminit vmemmap_populate_hugepages(unsigned long start, unsigned long end,					 int node, struct vmem_altmap *altmap){	unsigned long addr;	unsigned long next;	pgd_t *pgd;	p4d_t *p4d;	pud_t *pud;	pmd_t *pmd; 	for (addr = start; addr < end; addr = next) {		next = pmd_addr_end(addr, end); 		pgd = vmemmap_pgd_populate(addr, node);		if (!pgd)			return -ENOMEM; 		p4d = vmemmap_p4d_populate(pgd, addr, node);		if (!p4d)			return -ENOMEM; 		pud = vmemmap_pud_populate(p4d, addr, node);		if (!pud)			return -ENOMEM; 		pmd = pmd_offset(pud, addr);		if (pmd_none(pmdp_get(pmd))) {			void *p; 			p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap);			if (p) {				vmemmap_set_pmd(pmd, p, node, addr, next);				continue;			} else if (altmap) {				/*				 * No fallback: In any case we care about, the				 * altmap should be reasonably sized and aligned				 * such that vmemmap_alloc_block_buf() will always				 * succeed. For consistency with the PTE case,				 * return an error here as failure could indicate				 * a configuration issue with the size of the altmap.				 */				return -ENOMEM;			}		} else if (vmemmap_check_pmd(pmd, node, addr, next))			continue;		if (vmemmap_populate_basepages(addr, next, node, altmap))			return -ENOMEM;	}	return 0;} #ifndef vmemmap_populate_compound_pages/* * For compound pages bigger than section size (e.g. x86 1G compound * pages with 2M subsection size) fill the rest of sections as tail * pages. * * Note that memremap_pages() resets @nr_range value and will increment * it after each range successful onlining. Thus the value or @nr_range * at section memmap populate corresponds to the in-progress range * being onlined here. */static bool __meminit reuse_compound_section(unsigned long start_pfn,					     struct dev_pagemap *pgmap){	unsigned long nr_pages = pgmap_vmemmap_nr(pgmap);	unsigned long offset = start_pfn -		PHYS_PFN(pgmap->ranges[pgmap->nr_range].start); 	return !IS_ALIGNED(offset, nr_pages) && nr_pages > PAGES_PER_SUBSECTION;} static pte_t * __meminit compound_section_tail_page(unsigned long addr){	pte_t *pte; 	addr -= PAGE_SIZE; 	/*	 * Assuming sections are populated sequentially, the previous section's	 * page data can be reused.	 */	pte = pte_offset_kernel(pmd_off_k(addr), addr);	if (!pte)		return NULL; 	return pte;} static int __meminit vmemmap_populate_compound_pages(unsigned long start_pfn,						     unsigned long start,						     unsigned long end, int node,						     struct dev_pagemap *pgmap){	unsigned long size, addr;	pte_t *pte;

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