150 lines
4.0 KiB
C
150 lines
4.0 KiB
C
/*
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* Virtual Memory Map support
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*
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* (C) 2007 sgi. Christoph Lameter <clameter@sgi.com>.
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*
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* Virtual memory maps allow VM primitives pfn_to_page, page_to_pfn,
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* virt_to_page, page_address() to be implemented as a base offset
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* calculation without memory access.
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*
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* However, virtual mappings need a page table and TLBs. Many Linux
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* architectures already map their physical space using 1-1 mappings
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* via TLBs. For those arches the virtual memmory map is essentially
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* for free if we use the same page size as the 1-1 mappings. In that
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* case the overhead consists of a few additional pages that are
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* allocated to create a view of memory for vmemmap.
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*
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* The architecture is expected to provide a vmemmap_populate() function
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* to instantiate the mapping.
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*/
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#include <linux/mm.h>
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#include <linux/mmzone.h>
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#include <linux/bootmem.h>
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#include <linux/highmem.h>
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/vmalloc.h>
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#include <linux/sched.h>
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#include <asm/dma.h>
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#include <asm/pgalloc.h>
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#include <asm/pgtable.h>
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/*
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* Allocate a block of memory to be used to back the virtual memory map
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* or to back the page tables that are used to create the mapping.
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* Uses the main allocators if they are available, else bootmem.
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*/
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void * __meminit vmemmap_alloc_block(unsigned long size, int node)
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{
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/* If the main allocator is up use that, fallback to bootmem. */
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if (slab_is_available()) {
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struct page *page = alloc_pages_node(node,
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GFP_KERNEL | __GFP_ZERO, get_order(size));
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if (page)
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return page_address(page);
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return NULL;
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} else
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return __alloc_bootmem_node(NODE_DATA(node), size, size,
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__pa(MAX_DMA_ADDRESS));
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}
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void __meminit vmemmap_verify(pte_t *pte, int node,
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unsigned long start, unsigned long end)
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{
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unsigned long pfn = pte_pfn(*pte);
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int actual_node = early_pfn_to_nid(pfn);
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if (actual_node != node)
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printk(KERN_WARNING "[%lx-%lx] potential offnode "
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"page_structs\n", start, end - 1);
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}
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pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node)
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{
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pte_t *pte = pte_offset_kernel(pmd, addr);
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if (pte_none(*pte)) {
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pte_t entry;
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void *p = vmemmap_alloc_block(PAGE_SIZE, node);
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if (!p)
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return 0;
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entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
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set_pte_at(&init_mm, addr, pte, entry);
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}
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return pte;
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}
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pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node)
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{
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pmd_t *pmd = pmd_offset(pud, addr);
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if (pmd_none(*pmd)) {
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void *p = vmemmap_alloc_block(PAGE_SIZE, node);
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if (!p)
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return 0;
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pmd_populate_kernel(&init_mm, pmd, p);
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}
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return pmd;
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}
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pud_t * __meminit vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node)
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{
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pud_t *pud = pud_offset(pgd, addr);
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if (pud_none(*pud)) {
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void *p = vmemmap_alloc_block(PAGE_SIZE, node);
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if (!p)
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return 0;
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pud_populate(&init_mm, pud, p);
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}
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return pud;
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}
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pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node)
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{
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pgd_t *pgd = pgd_offset_k(addr);
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if (pgd_none(*pgd)) {
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void *p = vmemmap_alloc_block(PAGE_SIZE, node);
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if (!p)
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return 0;
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pgd_populate(&init_mm, pgd, p);
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}
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return pgd;
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}
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int __meminit vmemmap_populate_basepages(struct page *start_page,
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unsigned long size, int node)
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{
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unsigned long addr = (unsigned long)start_page;
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unsigned long end = (unsigned long)(start_page + size);
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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for (; addr < end; addr += PAGE_SIZE) {
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pgd = vmemmap_pgd_populate(addr, node);
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if (!pgd)
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return -ENOMEM;
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pud = vmemmap_pud_populate(pgd, addr, node);
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if (!pud)
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return -ENOMEM;
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pmd = vmemmap_pmd_populate(pud, addr, node);
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if (!pmd)
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return -ENOMEM;
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pte = vmemmap_pte_populate(pmd, addr, node);
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if (!pte)
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return -ENOMEM;
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vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
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}
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return 0;
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}
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struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid)
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{
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struct page *map = pfn_to_page(pnum * PAGES_PER_SECTION);
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int error = vmemmap_populate(map, PAGES_PER_SECTION, nid);
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if (error)
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return NULL;
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return map;
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}
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