162306a36Sopenharmony_ci// SPDX-License-Identifier: GPL-2.0-only 262306a36Sopenharmony_ci/* 362306a36Sopenharmony_ci * Copyright (C) 2011 Richard Weinberger <richrd@nod.at> 462306a36Sopenharmony_ci */ 562306a36Sopenharmony_ci 662306a36Sopenharmony_ci#include <linux/slab.h> 762306a36Sopenharmony_ci#include <linux/sched.h> 862306a36Sopenharmony_ci#include <linux/mm.h> 962306a36Sopenharmony_ci#include <asm/page.h> 1062306a36Sopenharmony_ci#include <asm/elf.h> 1162306a36Sopenharmony_ci#include <linux/init.h> 1262306a36Sopenharmony_ci 1362306a36Sopenharmony_cistatic unsigned int __read_mostly vdso_enabled = 1; 1462306a36Sopenharmony_ciunsigned long um_vdso_addr; 1562306a36Sopenharmony_ci 1662306a36Sopenharmony_ciextern unsigned long task_size; 1762306a36Sopenharmony_ciextern char vdso_start[], vdso_end[]; 1862306a36Sopenharmony_ci 1962306a36Sopenharmony_cistatic struct page **vdsop; 2062306a36Sopenharmony_ci 2162306a36Sopenharmony_cistatic int __init init_vdso(void) 2262306a36Sopenharmony_ci{ 2362306a36Sopenharmony_ci struct page *um_vdso; 2462306a36Sopenharmony_ci 2562306a36Sopenharmony_ci BUG_ON(vdso_end - vdso_start > PAGE_SIZE); 2662306a36Sopenharmony_ci 2762306a36Sopenharmony_ci um_vdso_addr = task_size - PAGE_SIZE; 2862306a36Sopenharmony_ci 2962306a36Sopenharmony_ci vdsop = kmalloc(sizeof(struct page *), GFP_KERNEL); 3062306a36Sopenharmony_ci if (!vdsop) 3162306a36Sopenharmony_ci goto oom; 3262306a36Sopenharmony_ci 3362306a36Sopenharmony_ci um_vdso = alloc_page(GFP_KERNEL); 3462306a36Sopenharmony_ci if (!um_vdso) { 3562306a36Sopenharmony_ci kfree(vdsop); 3662306a36Sopenharmony_ci 3762306a36Sopenharmony_ci goto oom; 3862306a36Sopenharmony_ci } 3962306a36Sopenharmony_ci 4062306a36Sopenharmony_ci copy_page(page_address(um_vdso), vdso_start); 4162306a36Sopenharmony_ci *vdsop = um_vdso; 4262306a36Sopenharmony_ci 4362306a36Sopenharmony_ci return 0; 4462306a36Sopenharmony_ci 4562306a36Sopenharmony_cioom: 4662306a36Sopenharmony_ci printk(KERN_ERR "Cannot allocate vdso\n"); 4762306a36Sopenharmony_ci vdso_enabled = 0; 4862306a36Sopenharmony_ci 4962306a36Sopenharmony_ci return -ENOMEM; 5062306a36Sopenharmony_ci} 5162306a36Sopenharmony_cisubsys_initcall(init_vdso); 5262306a36Sopenharmony_ci 5362306a36Sopenharmony_ciint arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 5462306a36Sopenharmony_ci{ 5562306a36Sopenharmony_ci int err; 5662306a36Sopenharmony_ci struct mm_struct *mm = current->mm; 5762306a36Sopenharmony_ci 5862306a36Sopenharmony_ci if (!vdso_enabled) 5962306a36Sopenharmony_ci return 0; 6062306a36Sopenharmony_ci 6162306a36Sopenharmony_ci if (mmap_write_lock_killable(mm)) 6262306a36Sopenharmony_ci return -EINTR; 6362306a36Sopenharmony_ci 6462306a36Sopenharmony_ci err = install_special_mapping(mm, um_vdso_addr, PAGE_SIZE, 6562306a36Sopenharmony_ci VM_READ|VM_EXEC| 6662306a36Sopenharmony_ci VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, 6762306a36Sopenharmony_ci vdsop); 6862306a36Sopenharmony_ci 6962306a36Sopenharmony_ci mmap_write_unlock(mm); 7062306a36Sopenharmony_ci 7162306a36Sopenharmony_ci return err; 7262306a36Sopenharmony_ci} 73