mm/sparse-vmemmap.c - arm/linux - Git at Google

 // 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/bootmem.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 <asm/dma.h>
 #include <asm/pgalloc.h>
 #include <asm/pgtable.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 memblock_virt_alloc_try_nid(size, align, goal,
 					    BOOTMEM_ALLOC_ACCESSIBLE, node);
 }

 static void *vmemmap_buf;
 static void *vmemmap_buf_end;

 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()) {
 		struct page *page;

 		page = alloc_pages_node(node,
 			GFP_KERNEL | __GFP_ZERO | __GFP_RETRY_MAYFAIL,
 			get_order(size));
 		if (page)
 			return page_address(page);
 		return NULL;
 	} else
 		return __earlyonly_bootmem_alloc(node, size, size,
 				__pa(MAX_DMA_ADDRESS));
 }

 /* need to make sure size is all the same during early stage */
 static void * __meminit alloc_block_buf(unsigned long size, int node)
 {
 	void *ptr;

 	if (!vmemmap_buf)
 		return vmemmap_alloc_block(size, node);

 	/* take the from buf */
 	ptr = (void *)ALIGN((unsigned long)vmemmap_buf, size);
 	if (ptr + size > vmemmap_buf_end)
 		return vmemmap_alloc_block(size, node);

 	vmemmap_buf = ptr + size;

 	return ptr;
 }

 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;
 }

 /**
  * vmem_altmap_alloc - allocate pages from the vmem_altmap reservation
  * @altmap - reserved page pool for the allocation
  * @nr_pfns - size (in pages) of the allocation
  *
  * Allocations are aligned to the size of the request
  */
 static unsigned long __meminit vmem_altmap_alloc(struct vmem_altmap *altmap,
 		unsigned long nr_pfns)
 {
 	unsigned long pfn = vmem_altmap_next_pfn(altmap);
 	unsigned long nr_align;

 	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 ULONG_MAX;
 	altmap->alloc += nr_pfns;
 	altmap->align += nr_align;
 	return pfn + nr_align;
 }

 static void * __meminit altmap_alloc_block_buf(unsigned long size,
 		struct vmem_altmap *altmap)
 {
 	unsigned long pfn, nr_pfns;
 	void *ptr;

 	if (size & ~PAGE_MASK) {
 		pr_warn_once("%s: allocations must be multiple of PAGE_SIZE (%ld)\n",
 				__func__, size);
 		return NULL;
 	}

 	nr_pfns = size >> PAGE_SHIFT;
 	pfn = vmem_altmap_alloc(altmap, nr_pfns);
 	if (pfn < ULONG_MAX)
 		ptr = __va(__pfn_to_phys(pfn));
 	else
 		ptr = NULL;
 	pr_debug("%s: pfn: %#lx alloc: %ld align: %ld nr: %#lx\n",
 			__func__, pfn, altmap->alloc, altmap->align, nr_pfns);

 	return ptr;
 }

 /* 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 alloc_block_buf(size, node);
 }

 void __meminit vmemmap_verify(pte_t *pte, int node,
 				unsigned long start, unsigned long end)
 {
 	unsigned long pfn = pte_pfn(*pte);
 	int actual_node = early_pfn_to_nid(pfn);

 	if (node_distance(actual_node, node) > LOCAL_DISTANCE)
 		pr_warn("[%lx-%lx] potential offnode page_structs\n",
 			start, end - 1);
 }

 pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node)
 {
 	pte_t *pte = pte_offset_kernel(pmd, addr);
 	if (pte_none(*pte)) {
 		pte_t entry;
 		void *p = alloc_block_buf(PAGE_SIZE, node);
 		if (!p)
 			return NULL;
 		entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
 		set_pte_at(&init_mm, addr, pte, entry);
 	}
 	return pte;
 }

 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(PAGE_SIZE, node);
 		if (!p)
 			return NULL;
 		pmd_populate_kernel(&init_mm, pmd, p);
 	}
 	return pmd;
 }

 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(PAGE_SIZE, node);
 		if (!p)
 			return NULL;
 		pud_populate(&init_mm, pud, p);
 	}
 	return pud;
 }

 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(PAGE_SIZE, node);
 		if (!p)
 			return NULL;
 		p4d_populate(&init_mm, p4d, p);
 	}
 	return p4d;
 }

 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(PAGE_SIZE, node);
 		if (!p)
 			return NULL;
 		pgd_populate(&init_mm, pgd, p);
 	}
 	return pgd;
 }

 int __meminit vmemmap_populate_basepages(unsigned long start,
 					 unsigned long end, int node)
 {
 	unsigned long addr = start;
 	pgd_t *pgd;
 	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;

 	for (; addr < end; addr += PAGE_SIZE) {
 		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 = vmemmap_pmd_populate(pud, addr, node);
 		if (!pmd)
 			return -ENOMEM;
 		pte = vmemmap_pte_populate(pmd, addr, node);
 		if (!pte)
 			return -ENOMEM;
 		vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
 	}

 	return 0;
 }

 struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid)
 {
 	unsigned long start;
 	unsigned long end;
 	struct page *map;

 	map = pfn_to_page(pnum * PAGES_PER_SECTION);
 	start = (unsigned long)map;
 	end = (unsigned long)(map + PAGES_PER_SECTION);

 	if (vmemmap_populate(start, end, nid))
 		return NULL;

 	return map;
 }

 void __init sparse_mem_maps_populate_node(struct page **map_map,
 					  unsigned long pnum_begin,
 					  unsigned long pnum_end,
 					  unsigned long map_count, int nodeid)
 {
 	unsigned long pnum;
 	unsigned long size = sizeof(struct page) * PAGES_PER_SECTION;
 	void *vmemmap_buf_start;

 	size = ALIGN(size, PMD_SIZE);
 	vmemmap_buf_start = __earlyonly_bootmem_alloc(nodeid, size * map_count,
 			 PMD_SIZE, __pa(MAX_DMA_ADDRESS));

 	if (vmemmap_buf_start) {
 		vmemmap_buf = vmemmap_buf_start;
 		vmemmap_buf_end = vmemmap_buf_start + size * map_count;
 	}

 	for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
 		struct mem_section *ms;

 		if (!present_section_nr(pnum))
 			continue;

 		map_map[pnum] = sparse_mem_map_populate(pnum, nodeid);
 		if (map_map[pnum])
 			continue;
 		ms = __nr_to_section(pnum);
 		pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
 		       __func__);
 		ms->section_mem_map = 0;
 	}

 	if (vmemmap_buf_start) {
 		/* need to free left buf */
 		memblock_free_early(__pa(vmemmap_buf),
 				    vmemmap_buf_end - vmemmap_buf);
 		vmemmap_buf = NULL;
 		vmemmap_buf_end = NULL;
 	}
 }
	// 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/bootmem.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 <asm/dma.h>
	#include <asm/pgalloc.h>
	#include <asm/pgtable.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 memblock_virt_alloc_try_nid(size, align, goal,
	BOOTMEM_ALLOC_ACCESSIBLE, node);
	}

	static void *vmemmap_buf;
	static void *vmemmap_buf_end;

	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()) {
	struct page *page;

	page = alloc_pages_node(node,
	GFP_KERNEL \| __GFP_ZERO \| __GFP_RETRY_MAYFAIL,
	get_order(size));
	if (page)
	return page_address(page);
	return NULL;
	} else
	return __earlyonly_bootmem_alloc(node, size, size,
	__pa(MAX_DMA_ADDRESS));
	}

	/* need to make sure size is all the same during early stage */
	static void * __meminit alloc_block_buf(unsigned long size, int node)
	{
	void *ptr;

	if (!vmemmap_buf)
	return vmemmap_alloc_block(size, node);

	/* take the from buf */
	ptr = (void *)ALIGN((unsigned long)vmemmap_buf, size);
	if (ptr + size > vmemmap_buf_end)
	return vmemmap_alloc_block(size, node);

	vmemmap_buf = ptr + size;

	return ptr;
	}

	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;
	}

	/**
	* vmem_altmap_alloc - allocate pages from the vmem_altmap reservation
	* @altmap - reserved page pool for the allocation
	* @nr_pfns - size (in pages) of the allocation
	*
	* Allocations are aligned to the size of the request
	*/
	static unsigned long __meminit vmem_altmap_alloc(struct vmem_altmap *altmap,
	unsigned long nr_pfns)
	{
	unsigned long pfn = vmem_altmap_next_pfn(altmap);
	unsigned long nr_align;

	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 ULONG_MAX;
	altmap->alloc += nr_pfns;
	altmap->align += nr_align;
	return pfn + nr_align;
	}

	static void * __meminit altmap_alloc_block_buf(unsigned long size,
	struct vmem_altmap *altmap)
	{
	unsigned long pfn, nr_pfns;
	void *ptr;

	if (size & ~PAGE_MASK) {
	pr_warn_once("%s: allocations must be multiple of PAGE_SIZE (%ld)\n",
	__func__, size);
	return NULL;
	}

	nr_pfns = size >> PAGE_SHIFT;
	pfn = vmem_altmap_alloc(altmap, nr_pfns);
	if (pfn < ULONG_MAX)
	ptr = __va(__pfn_to_phys(pfn));
	else
	ptr = NULL;
	pr_debug("%s: pfn: %#lx alloc: %ld align: %ld nr: %#lx\n",
	__func__, pfn, altmap->alloc, altmap->align, nr_pfns);

	return ptr;
	}

	/* 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 alloc_block_buf(size, node);
	}

	void __meminit vmemmap_verify(pte_t *pte, int node,
	unsigned long start, unsigned long end)
	{
	unsigned long pfn = pte_pfn(*pte);
	int actual_node = early_pfn_to_nid(pfn);

	if (node_distance(actual_node, node) > LOCAL_DISTANCE)
	pr_warn("[%lx-%lx] potential offnode page_structs\n",
	start, end - 1);
	}

	pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node)
	{
	pte_t *pte = pte_offset_kernel(pmd, addr);
	if (pte_none(*pte)) {
	pte_t entry;
	void *p = alloc_block_buf(PAGE_SIZE, node);
	if (!p)
	return NULL;
	entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
	set_pte_at(&init_mm, addr, pte, entry);
	}
	return pte;
	}

	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(PAGE_SIZE, node);
	if (!p)
	return NULL;
	pmd_populate_kernel(&init_mm, pmd, p);
	}
	return pmd;
	}

	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(PAGE_SIZE, node);
	if (!p)
	return NULL;
	pud_populate(&init_mm, pud, p);
	}
	return pud;
	}

	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(PAGE_SIZE, node);
	if (!p)
	return NULL;
	p4d_populate(&init_mm, p4d, p);
	}
	return p4d;
	}

	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(PAGE_SIZE, node);
	if (!p)
	return NULL;
	pgd_populate(&init_mm, pgd, p);
	}
	return pgd;
	}

	int __meminit vmemmap_populate_basepages(unsigned long start,
	unsigned long end, int node)
	{
	unsigned long addr = start;
	pgd_t *pgd;
	p4d_t *p4d;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;

	for (; addr < end; addr += PAGE_SIZE) {
	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 = vmemmap_pmd_populate(pud, addr, node);
	if (!pmd)
	return -ENOMEM;
	pte = vmemmap_pte_populate(pmd, addr, node);
	if (!pte)
	return -ENOMEM;
	vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
	}

	return 0;
	}

	struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid)
	{
	unsigned long start;
	unsigned long end;
	struct page *map;

	map = pfn_to_page(pnum * PAGES_PER_SECTION);
	start = (unsigned long)map;
	end = (unsigned long)(map + PAGES_PER_SECTION);

	if (vmemmap_populate(start, end, nid))
	return NULL;

	return map;
	}

	void __init sparse_mem_maps_populate_node(struct page **map_map,
	unsigned long pnum_begin,
	unsigned long pnum_end,
	unsigned long map_count, int nodeid)
	{
	unsigned long pnum;
	unsigned long size = sizeof(struct page) * PAGES_PER_SECTION;
	void *vmemmap_buf_start;

	size = ALIGN(size, PMD_SIZE);
	vmemmap_buf_start = __earlyonly_bootmem_alloc(nodeid, size * map_count,
	PMD_SIZE, __pa(MAX_DMA_ADDRESS));

	if (vmemmap_buf_start) {
	vmemmap_buf = vmemmap_buf_start;
	vmemmap_buf_end = vmemmap_buf_start + size * map_count;
	}

	for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
	struct mem_section *ms;

	if (!present_section_nr(pnum))
	continue;

	map_map[pnum] = sparse_mem_map_populate(pnum, nodeid);
	if (map_map[pnum])
	continue;
	ms = __nr_to_section(pnum);
	pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
	__func__);
	ms->section_mem_map = 0;
	}

	if (vmemmap_buf_start) {
	/* need to free left buf */
	memblock_free_early(__pa(vmemmap_buf),
	vmemmap_buf_end - vmemmap_buf);
	vmemmap_buf = NULL;
	vmemmap_buf_end = NULL;
	}
	}