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| 2 | |
| 3 |
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| 4 | #include <linux/binfmts.h>
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| 5 | #include <linux/elf.h>
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| 6 | #include <linux/err.h>
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| 7 | #include <linux/mm.h>
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| 8 | #include <linux/slab.h>
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| 9 |
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| 10 | #include <asm/page.h>
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| 11 |
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| 12 | extern char vdso_start[], vdso_end[];
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| 13 |
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| 14 | static unsigned int vdso_pages;
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| 15 | static struct page **vdso_pagelist;
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| 16 |
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| 17 | static int __init vdso_init(void)
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| 18 | {
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| 19 | unsigned int i;
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| 20 |
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| 21 | vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
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| 22 | vdso_pagelist =
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| 23 | kzalloc_objs(struct page *, vdso_pages);
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| 24 | if (unlikely(vdso_pagelist == NULL)) {
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| 25 | pr_err("vdso: pagelist allocation failed\n");
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| 26 | return -ENOMEM;
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| 27 | }
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| 28 |
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| 29 | for (i = 0; i < vdso_pages; i++) {
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| 30 | struct page *pg;
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| 31 |
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| 32 | pg = virt_to_page(vdso_start + (i << PAGE_SHIFT));
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| 33 | vdso_pagelist[i] = pg;
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| 34 | }
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| 35 |
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| 36 | return 0;
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| 37 | }
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| 38 | arch_initcall(vdso_init);
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| 39 |
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| 40 | int arch_setup_additional_pages(struct linux_binprm *bprm,
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| 41 | int uses_interp)
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| 42 | {
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| 43 | struct vm_area_struct *vma;
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| 44 | struct mm_struct *mm = current->mm;
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| 45 | unsigned long vdso_base, vdso_len;
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| 46 | int ret;
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| 47 | static struct vm_special_mapping vdso_mapping = {
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| 48 | .name = "[vdso]",
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| 49 | };
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| 50 |
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| 51 | vdso_len = vdso_pages << PAGE_SHIFT;
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| 52 |
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| 53 | mmap_write_lock(mm);
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| 54 | vdso_base = get_unmapped_area(NULL, 0, vdso_len, 0, 0);
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| 55 | if (IS_ERR_VALUE(vdso_base)) {
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| 56 | ret = vdso_base;
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| 57 | goto end;
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| 58 | }
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| 59 |
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| 60 | |
| 61 | * Put vDSO base into mm struct. We need to do this before calling
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| 62 | * install_special_mapping or the perf counter mmap tracking code
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| 63 | * will fail to recognise it as a vDSO (since arch_vma_name fails).
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| 64 |
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| 65 | mm->context.vdso = (void *)vdso_base;
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| 66 |
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| 67 | vdso_mapping.pages = vdso_pagelist;
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| 68 | vma =
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| 69 | _install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
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| 70 | (VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC),
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| 71 | &vdso_mapping);
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| 72 |
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| 73 | if (IS_ERR(vma)) {
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| 74 | ret = PTR_ERR(vma);
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| 75 | mm->context.vdso = NULL;
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| 76 | goto end;
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| 77 | }
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| 78 |
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| 79 | vdso_base += (vdso_pages << PAGE_SHIFT);
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| 80 | ret = 0;
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| 81 | end:
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| 82 | mmap_write_unlock(mm);
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| 83 | return ret;
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| 84 | }
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