/* * Virtual Memory Map support * * (C) 2007 sgi. Christoph Lameter <clameter@sgi.com>. * * 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 memmory 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/highmem.h> #include <linux/module.h> #include <linux/spinlock.h> #include <linux/vmalloc.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. */ 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 = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, get_order(size)); if (page) return page_address(page); return NULL; } else return __alloc_bootmem_node(NODE_DATA(node), size, size, __pa(MAX_DMA_ADDRESS)); } 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 (actual_node != node) printk(KERN_WARNING "[%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(PAGE_SIZE, node); if (!p) return 0; 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 0; pmd_populate_kernel(&init_mm, pmd, p); } return pmd; } pud_t * __meminit vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node) { pud_t *pud = pud_offset(pgd, addr); if (pud_none(*pud)) { void *p = vmemmap_alloc_block(PAGE_SIZE, node); if (!p) return 0; pud_populate(&init_mm, pud, p); } return pud; } 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 0; pgd_populate(&init_mm, pgd, p); } return pgd; } int __meminit vmemmap_populate_basepages(struct page *start_page, unsigned long size, int node) { unsigned long addr = (unsigned long)start_page; unsigned long end = (unsigned long)(start_page + size); pgd_t *pgd; 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; pud = vmemmap_pud_populate(pgd, 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) { struct page *map = pfn_to_page(pnum * PAGES_PER_SECTION); int error = vmemmap_populate(map, PAGES_PER_SECTION, nid); if (error) return NULL; return map; }