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398 lines
10 KiB
398 lines
10 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Virtual Memory Map support |
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* |
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* (C) 2007 sgi. Christoph Lameter. |
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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 memory 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/memblock.h> |
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#include <linux/memremap.h> |
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#include <linux/highmem.h> |
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#include <linux/slab.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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/* |
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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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static void * __ref __earlyonly_bootmem_alloc(int node, |
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unsigned long size, |
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unsigned long align, |
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unsigned long goal) |
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{ |
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return memblock_alloc_try_nid_raw(size, align, goal, |
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MEMBLOCK_ALLOC_ACCESSIBLE, node); |
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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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gfp_t gfp_mask = GFP_KERNEL|__GFP_RETRY_MAYFAIL|__GFP_NOWARN; |
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int order = get_order(size); |
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static bool warned; |
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struct page *page; |
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page = alloc_pages_node(node, gfp_mask, order); |
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if (page) |
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return page_address(page); |
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if (!warned) { |
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warn_alloc(gfp_mask & ~__GFP_NOWARN, NULL, |
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"vmemmap alloc failure: order:%u", order); |
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warned = true; |
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} |
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return NULL; |
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} else |
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return __earlyonly_bootmem_alloc(node, size, size, |
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__pa(MAX_DMA_ADDRESS)); |
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} |
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static void * __meminit altmap_alloc_block_buf(unsigned long size, |
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struct vmem_altmap *altmap); |
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|
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/* need to make sure size is all the same during early stage */ |
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void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node, |
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struct vmem_altmap *altmap) |
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{ |
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void *ptr; |
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if (altmap) |
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return altmap_alloc_block_buf(size, altmap); |
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ptr = sparse_buffer_alloc(size); |
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if (!ptr) |
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ptr = vmemmap_alloc_block(size, node); |
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return ptr; |
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} |
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static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap) |
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{ |
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return altmap->base_pfn + altmap->reserve + altmap->alloc |
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+ altmap->align; |
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} |
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static unsigned long __meminit vmem_altmap_nr_free(struct vmem_altmap *altmap) |
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{ |
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unsigned long allocated = altmap->alloc + altmap->align; |
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if (altmap->free > allocated) |
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return altmap->free - allocated; |
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return 0; |
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} |
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static void * __meminit altmap_alloc_block_buf(unsigned long size, |
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struct vmem_altmap *altmap) |
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{ |
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unsigned long pfn, nr_pfns, nr_align; |
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if (size & ~PAGE_MASK) { |
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pr_warn_once("%s: allocations must be multiple of PAGE_SIZE (%ld)\n", |
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__func__, size); |
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return NULL; |
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} |
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pfn = vmem_altmap_next_pfn(altmap); |
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nr_pfns = size >> PAGE_SHIFT; |
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nr_align = 1UL << find_first_bit(&nr_pfns, BITS_PER_LONG); |
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nr_align = ALIGN(pfn, nr_align) - pfn; |
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if (nr_pfns + nr_align > vmem_altmap_nr_free(altmap)) |
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return NULL; |
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altmap->alloc += nr_pfns; |
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altmap->align += nr_align; |
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pfn += nr_align; |
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pr_debug("%s: pfn: %#lx alloc: %ld align: %ld nr: %#lx\n", |
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__func__, pfn, altmap->alloc, altmap->align, nr_pfns); |
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return __va(__pfn_to_phys(pfn)); |
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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 (node_distance(actual_node, node) > LOCAL_DISTANCE) |
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pr_warn_once("[%lx-%lx] potential offnode page_structs\n", |
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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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struct vmem_altmap *altmap, |
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struct page *reuse) |
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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; |
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if (!reuse) { |
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p = vmemmap_alloc_block_buf(PAGE_SIZE, node, altmap); |
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if (!p) |
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return NULL; |
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} else { |
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/* |
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* When a PTE/PMD entry is freed from the init_mm |
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* there's a free_pages() call to this page allocated |
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* above. Thus this get_page() is paired with the |
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* put_page_testzero() on the freeing path. |
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* This can only called by certain ZONE_DEVICE path, |
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* and through vmemmap_populate_compound_pages() when |
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* slab is available. |
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*/ |
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get_page(reuse); |
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p = page_to_virt(reuse); |
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} |
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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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static void * __meminit vmemmap_alloc_block_zero(unsigned long size, int node) |
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{ |
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void *p = vmemmap_alloc_block(size, node); |
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if (!p) |
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return NULL; |
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memset(p, 0, size); |
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return p; |
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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_zero(PAGE_SIZE, node); |
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if (!p) |
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return NULL; |
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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(p4d_t *p4d, unsigned long addr, int node) |
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{ |
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pud_t *pud = pud_offset(p4d, addr); |
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if (pud_none(*pud)) { |
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void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); |
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if (!p) |
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return NULL; |
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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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p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node) |
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{ |
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p4d_t *p4d = p4d_offset(pgd, addr); |
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if (p4d_none(*p4d)) { |
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void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node); |
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if (!p) |
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return NULL; |
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p4d_populate(&init_mm, p4d, p); |
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} |
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return p4d; |
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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_zero(PAGE_SIZE, node); |
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if (!p) |
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return NULL; |
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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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static pte_t * __meminit vmemmap_populate_address(unsigned long addr, int node, |
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struct vmem_altmap *altmap, |
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struct page *reuse) |
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{ |
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pgd_t *pgd; |
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p4d_t *p4d; |
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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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pgd = vmemmap_pgd_populate(addr, node); |
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if (!pgd) |
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return NULL; |
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p4d = vmemmap_p4d_populate(pgd, addr, node); |
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if (!p4d) |
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return NULL; |
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pud = vmemmap_pud_populate(p4d, addr, node); |
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if (!pud) |
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return NULL; |
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pmd = vmemmap_pmd_populate(pud, addr, node); |
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if (!pmd) |
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return NULL; |
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pte = vmemmap_pte_populate(pmd, addr, node, altmap, reuse); |
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if (!pte) |
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return NULL; |
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vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); |
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return pte; |
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} |
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static int __meminit vmemmap_populate_range(unsigned long start, |
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unsigned long end, int node, |
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struct vmem_altmap *altmap, |
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struct page *reuse) |
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{ |
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unsigned long addr = start; |
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pte_t *pte; |
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for (; addr < end; addr += PAGE_SIZE) { |
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pte = vmemmap_populate_address(addr, node, altmap, reuse); |
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if (!pte) |
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return -ENOMEM; |
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} |
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return 0; |
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} |
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int __meminit vmemmap_populate_basepages(unsigned long start, unsigned long end, |
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int node, struct vmem_altmap *altmap) |
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{ |
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return vmemmap_populate_range(start, end, node, altmap, NULL); |
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} |
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/* |
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* For compound pages bigger than section size (e.g. x86 1G compound |
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* pages with 2M subsection size) fill the rest of sections as tail |
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* pages. |
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* |
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* Note that memremap_pages() resets @nr_range value and will increment |
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* it after each range successful onlining. Thus the value or @nr_range |
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* at section memmap populate corresponds to the in-progress range |
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* being onlined here. |
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*/ |
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static bool __meminit reuse_compound_section(unsigned long start_pfn, |
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struct dev_pagemap *pgmap) |
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{ |
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unsigned long nr_pages = pgmap_vmemmap_nr(pgmap); |
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unsigned long offset = start_pfn - |
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PHYS_PFN(pgmap->ranges[pgmap->nr_range].start); |
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return !IS_ALIGNED(offset, nr_pages) && nr_pages > PAGES_PER_SUBSECTION; |
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} |
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static pte_t * __meminit compound_section_tail_page(unsigned long addr) |
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{ |
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pte_t *pte; |
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addr -= PAGE_SIZE; |
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/* |
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* Assuming sections are populated sequentially, the previous section's |
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* page data can be reused. |
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*/ |
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pte = pte_offset_kernel(pmd_off_k(addr), addr); |
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if (!pte) |
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return NULL; |
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return pte; |
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} |
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static int __meminit vmemmap_populate_compound_pages(unsigned long start_pfn, |
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unsigned long start, |
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unsigned long end, int node, |
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struct dev_pagemap *pgmap) |
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{ |
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unsigned long size, addr; |
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pte_t *pte; |
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int rc; |
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if (reuse_compound_section(start_pfn, pgmap)) { |
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pte = compound_section_tail_page(start); |
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if (!pte) |
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return -ENOMEM; |
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/* |
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* Reuse the page that was populated in the prior iteration |
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* with just tail struct pages. |
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*/ |
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return vmemmap_populate_range(start, end, node, NULL, |
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pte_page(*pte)); |
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} |
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size = min(end - start, pgmap_vmemmap_nr(pgmap) * sizeof(struct page)); |
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for (addr = start; addr < end; addr += size) { |
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unsigned long next, last = addr + size; |
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/* Populate the head page vmemmap page */ |
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pte = vmemmap_populate_address(addr, node, NULL, NULL); |
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if (!pte) |
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return -ENOMEM; |
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/* Populate the tail pages vmemmap page */ |
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next = addr + PAGE_SIZE; |
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pte = vmemmap_populate_address(next, node, NULL, NULL); |
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if (!pte) |
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return -ENOMEM; |
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/* |
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* Reuse the previous page for the rest of tail pages |
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* See layout diagram in Documentation/mm/vmemmap_dedup.rst |
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*/ |
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next += PAGE_SIZE; |
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rc = vmemmap_populate_range(next, last, node, NULL, |
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pte_page(*pte)); |
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if (rc) |
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return -ENOMEM; |
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} |
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return 0; |
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} |
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struct page * __meminit __populate_section_memmap(unsigned long pfn, |
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unsigned long nr_pages, int nid, struct vmem_altmap *altmap, |
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struct dev_pagemap *pgmap) |
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{ |
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unsigned long start = (unsigned long) pfn_to_page(pfn); |
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unsigned long end = start + nr_pages * sizeof(struct page); |
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int r; |
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if (WARN_ON_ONCE(!IS_ALIGNED(pfn, PAGES_PER_SUBSECTION) || |
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!IS_ALIGNED(nr_pages, PAGES_PER_SUBSECTION))) |
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return NULL; |
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if (is_power_of_2(sizeof(struct page)) && |
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pgmap && pgmap_vmemmap_nr(pgmap) > 1 && !altmap) |
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r = vmemmap_populate_compound_pages(pfn, start, end, nid, pgmap); |
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else |
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r = vmemmap_populate(start, end, nid, altmap); |
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if (r < 0) |
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return NULL; |
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return pfn_to_page(pfn); |
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}
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