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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2004 Benjamin Herrenschmidt, IBM Corp.
* <benh@kernel.crashing.org>
* Copyright (C) 2012 ARM Limited
* Copyright (C) 2015 Regents of the University of California
*/
#include <linux/elf.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/binfmts.h>
#include <linux/err.h>
#include <asm/page.h>
#include <asm/vdso.h>
#include <linux/vdso_datastore.h>
#include <vdso/datapage.h>
#include <vdso/vsyscall.h>
#define VVAR_SIZE (VDSO_NR_PAGES << PAGE_SHIFT)
struct __vdso_info {
const char *name;
const char *vdso_code_start;
const char *vdso_code_end;
unsigned long vdso_pages;
/* Code Mapping */
struct vm_special_mapping *cm;
};
static struct __vdso_info vdso_info;
#ifdef CONFIG_COMPAT
static struct __vdso_info compat_vdso_info;
#endif
static int vdso_mremap(const struct vm_special_mapping *sm,
struct vm_area_struct *new_vma)
{
current->mm->context.vdso = (void *)new_vma->vm_start;
return 0;
}
static void __init __vdso_init(struct __vdso_info *vdso_info)
{
unsigned int i;
struct page **vdso_pagelist;
unsigned long pfn;
if (memcmp(vdso_info->vdso_code_start, "\177ELF", 4))
panic("vDSO is not a valid ELF object!\n");
vdso_info->vdso_pages = (
vdso_info->vdso_code_end -
vdso_info->vdso_code_start) >>
PAGE_SHIFT;
vdso_pagelist = kcalloc(vdso_info->vdso_pages,
sizeof(struct page *),
GFP_KERNEL);
if (vdso_pagelist == NULL)
panic("vDSO kcalloc failed!\n");
/* Grab the vDSO code pages. */
pfn = sym_to_pfn(vdso_info->vdso_code_start);
for (i = 0; i < vdso_info->vdso_pages; i++)
vdso_pagelist[i] = pfn_to_page(pfn + i);
vdso_info->cm->pages = vdso_pagelist;
}
static struct vm_special_mapping rv_vdso_map __ro_after_init = {
.name = "[vdso]",
.mremap = vdso_mremap,
};
static struct __vdso_info vdso_info __ro_after_init = {
.name = "vdso",
.vdso_code_start = vdso_start,
.vdso_code_end = vdso_end,
.cm = &rv_vdso_map,
};
#ifdef CONFIG_COMPAT
static struct vm_special_mapping rv_compat_vdso_map __ro_after_init = {
.name = "[vdso]",
.mremap = vdso_mremap,
};
static struct __vdso_info compat_vdso_info __ro_after_init = {
.name = "compat_vdso",
.vdso_code_start = compat_vdso_start,
.vdso_code_end = compat_vdso_end,
.cm = &rv_compat_vdso_map,
};
#endif
static int __init vdso_init(void)
{
__vdso_init(&vdso_info);
#ifdef CONFIG_COMPAT
__vdso_init(&compat_vdso_info);
#endif
return 0;
}
arch_initcall(vdso_init);
static int __setup_additional_pages(struct mm_struct *mm,
struct linux_binprm *bprm,
int uses_interp,
struct __vdso_info *vdso_info)
{
unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
void *ret;
BUILD_BUG_ON(VDSO_NR_PAGES != __VDSO_PAGES);
vdso_text_len = vdso_info->vdso_pages << PAGE_SHIFT;
/* Be sure to map the data page */
vdso_mapping_len = vdso_text_len + VVAR_SIZE;
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;
}
ret = vdso_install_vvar_mapping(mm, vdso_base);
if (IS_ERR(ret))
goto up_fail;
vdso_base += VVAR_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_info->cm);
if (IS_ERR(ret))
goto up_fail;
return 0;
up_fail:
mm->context.vdso = NULL;
return PTR_ERR(ret);
}
#ifdef CONFIG_COMPAT
int compat_arch_setup_additional_pages(struct linux_binprm *bprm,
int uses_interp)
{
struct mm_struct *mm = current->mm;
int ret;
if (mmap_write_lock_killable(mm))
return -EINTR;
ret = __setup_additional_pages(mm, bprm, uses_interp,
&compat_vdso_info);
mmap_write_unlock(mm);
return ret;
}
#endif
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
struct mm_struct *mm = current->mm;
int ret;
if (mmap_write_lock_killable(mm))
return -EINTR;
ret = __setup_additional_pages(mm, bprm, uses_interp, &vdso_info);
mmap_write_unlock(mm);
return ret;
}
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