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619 lines
16 KiB
619 lines
16 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
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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 <linux/pgtable.h> |
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#include <linux/bootmem_info.h> |
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|
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#include <asm/dma.h> |
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#include <asm/pgalloc.h> |
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#include <asm/tlbflush.h> |
|
|
|
/** |
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* struct vmemmap_remap_walk - walk vmemmap page table |
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* |
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* @remap_pte: called for each lowest-level entry (PTE). |
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* @nr_walked: the number of walked pte. |
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* @reuse_page: the page which is reused for the tail vmemmap pages. |
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* @reuse_addr: the virtual address of the @reuse_page page. |
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* @vmemmap_pages: the list head of the vmemmap pages that can be freed |
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* or is mapped from. |
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*/ |
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struct vmemmap_remap_walk { |
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void (*remap_pte)(pte_t *pte, unsigned long addr, |
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struct vmemmap_remap_walk *walk); |
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unsigned long nr_walked; |
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struct page *reuse_page; |
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unsigned long reuse_addr; |
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struct list_head *vmemmap_pages; |
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}; |
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|
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static int split_vmemmap_huge_pmd(pmd_t *pmd, unsigned long start, |
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struct vmemmap_remap_walk *walk) |
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{ |
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pmd_t __pmd; |
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int i; |
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unsigned long addr = start; |
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struct page *page = pmd_page(*pmd); |
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pte_t *pgtable = pte_alloc_one_kernel(&init_mm); |
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|
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if (!pgtable) |
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return -ENOMEM; |
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|
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pmd_populate_kernel(&init_mm, &__pmd, pgtable); |
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|
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for (i = 0; i < PMD_SIZE / PAGE_SIZE; i++, addr += PAGE_SIZE) { |
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pte_t entry, *pte; |
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pgprot_t pgprot = PAGE_KERNEL; |
|
|
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entry = mk_pte(page + i, pgprot); |
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pte = pte_offset_kernel(&__pmd, addr); |
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set_pte_at(&init_mm, addr, pte, entry); |
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} |
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|
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/* Make pte visible before pmd. See comment in __pte_alloc(). */ |
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smp_wmb(); |
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pmd_populate_kernel(&init_mm, pmd, pgtable); |
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|
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flush_tlb_kernel_range(start, start + PMD_SIZE); |
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|
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return 0; |
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} |
|
|
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static void vmemmap_pte_range(pmd_t *pmd, unsigned long addr, |
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unsigned long end, |
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struct vmemmap_remap_walk *walk) |
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{ |
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pte_t *pte = pte_offset_kernel(pmd, addr); |
|
|
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/* |
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* The reuse_page is found 'first' in table walk before we start |
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* remapping (which is calling @walk->remap_pte). |
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*/ |
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if (!walk->reuse_page) { |
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walk->reuse_page = pte_page(*pte); |
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/* |
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* Because the reuse address is part of the range that we are |
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* walking, skip the reuse address range. |
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*/ |
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addr += PAGE_SIZE; |
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pte++; |
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walk->nr_walked++; |
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} |
|
|
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for (; addr != end; addr += PAGE_SIZE, pte++) { |
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walk->remap_pte(pte, addr, walk); |
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walk->nr_walked++; |
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} |
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} |
|
|
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static int vmemmap_pmd_range(pud_t *pud, unsigned long addr, |
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unsigned long end, |
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struct vmemmap_remap_walk *walk) |
|
{ |
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pmd_t *pmd; |
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unsigned long next; |
|
|
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pmd = pmd_offset(pud, addr); |
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do { |
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if (pmd_leaf(*pmd)) { |
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int ret; |
|
|
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ret = split_vmemmap_huge_pmd(pmd, addr & PMD_MASK, walk); |
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if (ret) |
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return ret; |
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} |
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next = pmd_addr_end(addr, end); |
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vmemmap_pte_range(pmd, addr, next, walk); |
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} while (pmd++, addr = next, addr != end); |
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|
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return 0; |
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} |
|
|
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static int vmemmap_pud_range(p4d_t *p4d, unsigned long addr, |
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unsigned long end, |
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struct vmemmap_remap_walk *walk) |
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{ |
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pud_t *pud; |
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unsigned long next; |
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|
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pud = pud_offset(p4d, addr); |
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do { |
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int ret; |
|
|
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next = pud_addr_end(addr, end); |
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ret = vmemmap_pmd_range(pud, addr, next, walk); |
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if (ret) |
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return ret; |
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} while (pud++, addr = next, addr != end); |
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|
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return 0; |
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} |
|
|
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static int vmemmap_p4d_range(pgd_t *pgd, unsigned long addr, |
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unsigned long end, |
|
struct vmemmap_remap_walk *walk) |
|
{ |
|
p4d_t *p4d; |
|
unsigned long next; |
|
|
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p4d = p4d_offset(pgd, addr); |
|
do { |
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int ret; |
|
|
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next = p4d_addr_end(addr, end); |
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ret = vmemmap_pud_range(p4d, addr, next, walk); |
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if (ret) |
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return ret; |
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} while (p4d++, addr = next, addr != end); |
|
|
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return 0; |
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} |
|
|
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static int vmemmap_remap_range(unsigned long start, unsigned long end, |
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struct vmemmap_remap_walk *walk) |
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{ |
|
unsigned long addr = start; |
|
unsigned long next; |
|
pgd_t *pgd; |
|
|
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VM_BUG_ON(!IS_ALIGNED(start, PAGE_SIZE)); |
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VM_BUG_ON(!IS_ALIGNED(end, PAGE_SIZE)); |
|
|
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pgd = pgd_offset_k(addr); |
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do { |
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int ret; |
|
|
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next = pgd_addr_end(addr, end); |
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ret = vmemmap_p4d_range(pgd, addr, next, walk); |
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if (ret) |
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return ret; |
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} while (pgd++, addr = next, addr != end); |
|
|
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/* |
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* We only change the mapping of the vmemmap virtual address range |
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* [@start + PAGE_SIZE, end), so we only need to flush the TLB which |
|
* belongs to the range. |
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*/ |
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flush_tlb_kernel_range(start + PAGE_SIZE, end); |
|
|
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return 0; |
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} |
|
|
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/* |
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* Free a vmemmap page. A vmemmap page can be allocated from the memblock |
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* allocator or buddy allocator. If the PG_reserved flag is set, it means |
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* that it allocated from the memblock allocator, just free it via the |
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* free_bootmem_page(). Otherwise, use __free_page(). |
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*/ |
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static inline void free_vmemmap_page(struct page *page) |
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{ |
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if (PageReserved(page)) |
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free_bootmem_page(page); |
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else |
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__free_page(page); |
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} |
|
|
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/* Free a list of the vmemmap pages */ |
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static void free_vmemmap_page_list(struct list_head *list) |
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{ |
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struct page *page, *next; |
|
|
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list_for_each_entry_safe(page, next, list, lru) { |
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list_del(&page->lru); |
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free_vmemmap_page(page); |
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} |
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} |
|
|
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static void vmemmap_remap_pte(pte_t *pte, unsigned long addr, |
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struct vmemmap_remap_walk *walk) |
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{ |
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/* |
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* Remap the tail pages as read-only to catch illegal write operation |
|
* to the tail pages. |
|
*/ |
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pgprot_t pgprot = PAGE_KERNEL_RO; |
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pte_t entry = mk_pte(walk->reuse_page, pgprot); |
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struct page *page = pte_page(*pte); |
|
|
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list_add_tail(&page->lru, walk->vmemmap_pages); |
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set_pte_at(&init_mm, addr, pte, entry); |
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} |
|
|
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static void vmemmap_restore_pte(pte_t *pte, unsigned long addr, |
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struct vmemmap_remap_walk *walk) |
|
{ |
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pgprot_t pgprot = PAGE_KERNEL; |
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struct page *page; |
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void *to; |
|
|
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BUG_ON(pte_page(*pte) != walk->reuse_page); |
|
|
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page = list_first_entry(walk->vmemmap_pages, struct page, lru); |
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list_del(&page->lru); |
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to = page_to_virt(page); |
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copy_page(to, (void *)walk->reuse_addr); |
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|
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set_pte_at(&init_mm, addr, pte, mk_pte(page, pgprot)); |
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} |
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|
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/** |
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* vmemmap_remap_free - remap the vmemmap virtual address range [@start, @end) |
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* to the page which @reuse is mapped to, then free vmemmap |
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* which the range are mapped to. |
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* @start: start address of the vmemmap virtual address range that we want |
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* to remap. |
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* @end: end address of the vmemmap virtual address range that we want to |
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* remap. |
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* @reuse: reuse address. |
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* |
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* Return: %0 on success, negative error code otherwise. |
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*/ |
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int vmemmap_remap_free(unsigned long start, unsigned long end, |
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unsigned long reuse) |
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{ |
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int ret; |
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LIST_HEAD(vmemmap_pages); |
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struct vmemmap_remap_walk walk = { |
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.remap_pte = vmemmap_remap_pte, |
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.reuse_addr = reuse, |
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.vmemmap_pages = &vmemmap_pages, |
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}; |
|
|
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/* |
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* In order to make remapping routine most efficient for the huge pages, |
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* the routine of vmemmap page table walking has the following rules |
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* (see more details from the vmemmap_pte_range()): |
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* |
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* - The range [@start, @end) and the range [@reuse, @reuse + PAGE_SIZE) |
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* should be continuous. |
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* - The @reuse address is part of the range [@reuse, @end) that we are |
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* walking which is passed to vmemmap_remap_range(). |
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* - The @reuse address is the first in the complete range. |
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* |
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* So we need to make sure that @start and @reuse meet the above rules. |
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*/ |
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BUG_ON(start - reuse != PAGE_SIZE); |
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|
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mmap_write_lock(&init_mm); |
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ret = vmemmap_remap_range(reuse, end, &walk); |
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mmap_write_downgrade(&init_mm); |
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|
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if (ret && walk.nr_walked) { |
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end = reuse + walk.nr_walked * PAGE_SIZE; |
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/* |
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* vmemmap_pages contains pages from the previous |
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* vmemmap_remap_range call which failed. These |
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* are pages which were removed from the vmemmap. |
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* They will be restored in the following call. |
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*/ |
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walk = (struct vmemmap_remap_walk) { |
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.remap_pte = vmemmap_restore_pte, |
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.reuse_addr = reuse, |
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.vmemmap_pages = &vmemmap_pages, |
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}; |
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|
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vmemmap_remap_range(reuse, end, &walk); |
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} |
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mmap_read_unlock(&init_mm); |
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|
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free_vmemmap_page_list(&vmemmap_pages); |
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|
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return ret; |
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} |
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|
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static int alloc_vmemmap_page_list(unsigned long start, unsigned long end, |
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gfp_t gfp_mask, struct list_head *list) |
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{ |
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unsigned long nr_pages = (end - start) >> PAGE_SHIFT; |
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int nid = page_to_nid((struct page *)start); |
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struct page *page, *next; |
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|
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while (nr_pages--) { |
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page = alloc_pages_node(nid, gfp_mask, 0); |
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if (!page) |
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goto out; |
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list_add_tail(&page->lru, list); |
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} |
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|
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return 0; |
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out: |
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list_for_each_entry_safe(page, next, list, lru) |
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__free_pages(page, 0); |
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return -ENOMEM; |
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} |
|
|
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/** |
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* vmemmap_remap_alloc - remap the vmemmap virtual address range [@start, end) |
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* to the page which is from the @vmemmap_pages |
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* respectively. |
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* @start: start address of the vmemmap virtual address range that we want |
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* to remap. |
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* @end: end address of the vmemmap virtual address range that we want to |
|
* remap. |
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* @reuse: reuse address. |
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* @gfp_mask: GFP flag for allocating vmemmap pages. |
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* |
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* Return: %0 on success, negative error code otherwise. |
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*/ |
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int vmemmap_remap_alloc(unsigned long start, unsigned long end, |
|
unsigned long reuse, gfp_t gfp_mask) |
|
{ |
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LIST_HEAD(vmemmap_pages); |
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struct vmemmap_remap_walk walk = { |
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.remap_pte = vmemmap_restore_pte, |
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.reuse_addr = reuse, |
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.vmemmap_pages = &vmemmap_pages, |
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}; |
|
|
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/* See the comment in the vmemmap_remap_free(). */ |
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BUG_ON(start - reuse != PAGE_SIZE); |
|
|
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if (alloc_vmemmap_page_list(start, end, gfp_mask, &vmemmap_pages)) |
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return -ENOMEM; |
|
|
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mmap_read_lock(&init_mm); |
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vmemmap_remap_range(reuse, end, &walk); |
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mmap_read_unlock(&init_mm); |
|
|
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return 0; |
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} |
|
|
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/* |
|
* 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. |
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* Uses the main allocators if they are available, else bootmem. |
|
*/ |
|
|
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static void * __ref __earlyonly_bootmem_alloc(int node, |
|
unsigned long size, |
|
unsigned long align, |
|
unsigned long goal) |
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{ |
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return memblock_alloc_try_nid_raw(size, align, goal, |
|
MEMBLOCK_ALLOC_ACCESSIBLE, node); |
|
} |
|
|
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void * __meminit vmemmap_alloc_block(unsigned long size, int node) |
|
{ |
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/* 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; |
|
|
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page = alloc_pages_node(node, gfp_mask, order); |
|
if (page) |
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return page_address(page); |
|
|
|
if (!warned) { |
|
warn_alloc(gfp_mask & ~__GFP_NOWARN, NULL, |
|
"vmemmap alloc failure: order:%u", order); |
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warned = true; |
|
} |
|
return NULL; |
|
} else |
|
return __earlyonly_bootmem_alloc(node, size, size, |
|
__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); |
|
|
|
/* 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) |
|
{ |
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void *ptr; |
|
|
|
if (altmap) |
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return altmap_alloc_block_buf(size, altmap); |
|
|
|
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; |
|
} |
|
|
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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; |
|
} |
|
|
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static void * __meminit altmap_alloc_block_buf(unsigned long size, |
|
struct vmem_altmap *altmap) |
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{ |
|
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, |
|
struct vmem_altmap *altmap) |
|
{ |
|
pte_t *pte = pte_offset_kernel(pmd, addr); |
|
if (pte_none(*pte)) { |
|
pte_t entry; |
|
void *p; |
|
|
|
p = vmemmap_alloc_block_buf(PAGE_SIZE, node, altmap); |
|
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, struct vmem_altmap *altmap) |
|
{ |
|
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, altmap); |
|
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) pfn_to_page(pfn); |
|
unsigned long end = start + nr_pages * sizeof(struct page); |
|
|
|
if (WARN_ON_ONCE(!IS_ALIGNED(pfn, PAGES_PER_SUBSECTION) || |
|
!IS_ALIGNED(nr_pages, PAGES_PER_SUBSECTION))) |
|
return NULL; |
|
|
|
if (vmemmap_populate(start, end, nid, altmap)) |
|
return NULL; |
|
|
|
return pfn_to_page(pfn); |
|
}
|
|
|