diff options
| -rw-r--r-- | arch/arm64/kernel/vdso.c | 103 |
1 files changed, 61 insertions, 42 deletions
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index aea0b929d0b4..17697320ce29 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -38,9 +38,11 @@ #include <asm/vdso.h> #include <asm/vdso_datapage.h> -extern char vdso_start[], vdso_end[]; -static unsigned long vdso_pages; -static struct page **vdso_pagelist; +struct vdso_mappings { + unsigned long num_code_pages; + struct vm_special_mapping data_mapping; + struct vm_special_mapping code_mapping; +}; /* * The vDSO data page. @@ -149,93 +151,110 @@ out: } #endif /* CONFIG_COMPAT */ -static struct vm_special_mapping vdso_spec[2]; - -static int __init vdso_init(void) +static int __init vdso_mappings_init(const char *name, + const char *code_start, + const char *code_end, + struct vdso_mappings *mappings) { - int i; + unsigned long i, vdso_pages; + struct page **vdso_pagelist; unsigned long pfn; - if (memcmp(vdso_start, "\177ELF", 4)) { - pr_err("vDSO is not a valid ELF object!\n"); + if (memcmp(code_start, "\177ELF", 4)) { + pr_err("%s is not a valid ELF object!\n", name); return -EINVAL; } - vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT; - pr_info("vdso: %ld pages (%ld code @ %p, %ld data @ %p)\n", - vdso_pages + 1, vdso_pages, vdso_start, 1L, vdso_data); - - /* Allocate the vDSO pagelist, plus a page for the data. */ - vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *), - GFP_KERNEL); + vdso_pages = (code_end - code_start) >> PAGE_SHIFT; + pr_info("%s: %ld pages (%ld code @ %p, %ld data @ %p)\n", + name, vdso_pages + 1, vdso_pages, code_start, 1L, + vdso_data); + + /* + * Allocate space for storing pointers to the vDSO code pages + the + * data page. The pointers must have the same lifetime as the mappings, + * which are static, so there is no need to keep track of the pointer + * array to free it. + */ + vdso_pagelist = kmalloc_array(vdso_pages + 1, sizeof(struct page *), + GFP_KERNEL); if (vdso_pagelist == NULL) return -ENOMEM; /* Grab the vDSO data page. */ vdso_pagelist[0] = phys_to_page(__pa_symbol(vdso_data)); - /* Grab the vDSO code pages. */ - pfn = sym_to_pfn(vdso_start); + pfn = sym_to_pfn(code_start); for (i = 0; i < vdso_pages; i++) vdso_pagelist[i + 1] = pfn_to_page(pfn + i); /* Populate the special mapping structures */ - vdso_spec[0] = (struct vm_special_mapping) { + mappings->data_mapping = (struct vm_special_mapping) { .name = "[vvar]", - .pages = vdso_pagelist, + .pages = &vdso_pagelist[0], }; - vdso_spec[1] = (struct vm_special_mapping) { + mappings->code_mapping = (struct vm_special_mapping) { .name = "[vdso]", .pages = &vdso_pagelist[1], }; + mappings->num_code_pages = vdso_pages; return 0; } + +static struct vdso_mappings vdso_mappings __ro_after_init; + +static int __init vdso_init(void) +{ + extern char vdso_start[], vdso_end[]; + + return vdso_mappings_init("vdso", vdso_start, vdso_end, + &vdso_mappings); +} + arch_initcall(vdso_init); -int arch_setup_additional_pages(struct linux_binprm *bprm, - int uses_interp) +static int vdso_setup(struct mm_struct *mm, + const struct vdso_mappings *mappings) { - struct mm_struct *mm = current->mm; unsigned long vdso_base, vdso_text_len, vdso_mapping_len; void *ret; - vdso_text_len = vdso_pages << PAGE_SHIFT; + vdso_text_len = mappings->num_code_pages << PAGE_SHIFT; /* Be sure to map the data page */ vdso_mapping_len = vdso_text_len + PAGE_SIZE; - down_write(&mm->mmap_sem); vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0); - if (IS_ERR_VALUE(vdso_base)) { - ret = ERR_PTR(vdso_base); - goto up_fail; - } + if (IS_ERR_VALUE(vdso_base)) + return PTR_ERR_OR_ZERO(ERR_PTR(vdso_base)); ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE, VM_READ|VM_MAYREAD, - &vdso_spec[0]); + &mappings->data_mapping); if (IS_ERR(ret)) - goto up_fail; + return PTR_ERR_OR_ZERO(ret); vdso_base += PAGE_SIZE; - mm->context.vdso = (void *)vdso_base; ret = _install_special_mapping(mm, vdso_base, vdso_text_len, VM_READ|VM_EXEC| VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, - &vdso_spec[1]); - if (IS_ERR(ret)) - goto up_fail; - + &mappings->code_mapping); + if (!IS_ERR(ret)) + mm->context.vdso = (void *)vdso_base; + return PTR_ERR_OR_ZERO(ret); +} - up_write(&mm->mmap_sem); - return 0; +int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) +{ + struct mm_struct *mm = current->mm; + int ret; -up_fail: - mm->context.vdso = NULL; + down_write(&mm->mmap_sem); + ret = vdso_setup(mm, &vdso_mappings); up_write(&mm->mmap_sem); - return PTR_ERR(ret); + return ret; } /* |