// 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 <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_alloc_try_nid_raw(size, align, goal, MEMBLOCK_ALLOC_ACCESSIBLE, node); } 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; 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)); } /* need to make sure size is all the same during early stage */ void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node) { void *ptr = sparse_buffer_alloc(size); if (!ptr) ptr = vmemmap_alloc_block(size, node); 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; } /** * altmap_alloc_block_buf - allocate pages from the device page map * @altmap: device page map * @size: size (in bytes) of the allocation * * Allocations are aligned to the size of the request. */ 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(*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 = vmemmap_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; } 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; } 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; 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_zero(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_zero(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_zero(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 __populate_section_memmap(unsigned long pfn, unsigned long nr_pages, int nid, struct vmem_altmap *altmap) { unsigned long start; unsigned long end; /* * The minimum granularity of memmap extensions is * PAGES_PER_SUBSECTION as allocations are tracked in the * 'subsection_map' bitmap of the section. */ end = ALIGN(pfn + nr_pages, PAGES_PER_SUBSECTION); pfn &= PAGE_SUBSECTION_MASK; nr_pages = end - pfn; start = (unsigned long) pfn_to_page(pfn); end = start + nr_pages * sizeof(struct page); if (vmemmap_populate(start, end, nid, altmap)) return NULL; return pfn_to_page(pfn); }