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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
*/
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <asm/page.h>
#include <asm/elf.h>
#include <linux/init.h>
static unsigned int __read_mostly vdso_enabled = 1;
unsigned long um_vdso_addr;
extern unsigned long task_size;
extern char vdso_start[], vdso_end[];
static struct page **vdsop;
static int __init init_vdso(void)
{
struct page *um_vdso;
BUG_ON(vdso_end - vdso_start > PAGE_SIZE);
um_vdso_addr = task_size - PAGE_SIZE;
vdsop = kmalloc(sizeof(struct page *), GFP_KERNEL);
if (!vdsop)
goto oom;
um_vdso = alloc_page(GFP_KERNEL);
if (!um_vdso) {
kfree(vdsop);
goto oom;
}
copy_page(page_address(um_vdso), vdso_start);
*vdsop = um_vdso;
return 0;
oom:
printk(KERN_ERR "Cannot allocate vdso\n");
vdso_enabled = 0;
return -ENOMEM;
}
subsys_initcall(init_vdso);
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
int err;
struct mm_struct *mm = current->mm;
if (!vdso_enabled)
return 0;
if (down_write_killable(&mm->mmap_sem))
return -EINTR;
err = install_special_mapping(mm, um_vdso_addr, PAGE_SIZE,
VM_READ|VM_EXEC|
VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
vdsop);
up_write(&mm->mmap_sem);
return err;
}
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