126 lines
3.0 KiB
C
126 lines
3.0 KiB
C
/*
|
|
* 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
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include <linux/mm.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/binfmts.h>
|
|
#include <linux/err.h>
|
|
|
|
#include <asm/vdso.h>
|
|
|
|
extern char vdso_start[], vdso_end[];
|
|
|
|
static unsigned int vdso_pages;
|
|
static struct page **vdso_pagelist;
|
|
|
|
/*
|
|
* The vDSO data page.
|
|
*/
|
|
static union {
|
|
struct vdso_data data;
|
|
u8 page[PAGE_SIZE];
|
|
} vdso_data_store __page_aligned_data;
|
|
struct vdso_data *vdso_data = &vdso_data_store.data;
|
|
|
|
static int __init vdso_init(void)
|
|
{
|
|
unsigned int i;
|
|
|
|
vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
|
|
vdso_pagelist =
|
|
kcalloc(vdso_pages + 1, sizeof(struct page *), GFP_KERNEL);
|
|
if (unlikely(vdso_pagelist == NULL)) {
|
|
pr_err("vdso: pagelist allocation failed\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
for (i = 0; i < vdso_pages; i++) {
|
|
struct page *pg;
|
|
|
|
pg = virt_to_page(vdso_start + (i << PAGE_SHIFT));
|
|
ClearPageReserved(pg);
|
|
vdso_pagelist[i] = pg;
|
|
}
|
|
vdso_pagelist[i] = virt_to_page(vdso_data);
|
|
|
|
return 0;
|
|
}
|
|
arch_initcall(vdso_init);
|
|
|
|
int arch_setup_additional_pages(struct linux_binprm *bprm,
|
|
int uses_interp)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
unsigned long vdso_base, vdso_len;
|
|
int ret;
|
|
|
|
vdso_len = (vdso_pages + 1) << PAGE_SHIFT;
|
|
|
|
down_write(&mm->mmap_sem);
|
|
vdso_base = get_unmapped_area(NULL, 0, vdso_len, 0, 0);
|
|
if (IS_ERR_VALUE(vdso_base)) {
|
|
ret = vdso_base;
|
|
goto end;
|
|
}
|
|
|
|
/*
|
|
* Put vDSO base into mm struct. We need to do this before calling
|
|
* install_special_mapping or the perf counter mmap tracking code
|
|
* will fail to recognise it as a vDSO (since arch_vma_name fails).
|
|
*/
|
|
mm->context.vdso = (void *)vdso_base;
|
|
|
|
ret = install_special_mapping(mm, vdso_base, vdso_len,
|
|
(VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC),
|
|
vdso_pagelist);
|
|
|
|
if (unlikely(ret))
|
|
mm->context.vdso = NULL;
|
|
|
|
end:
|
|
up_write(&mm->mmap_sem);
|
|
return ret;
|
|
}
|
|
|
|
const char *arch_vma_name(struct vm_area_struct *vma)
|
|
{
|
|
if (vma->vm_mm && (vma->vm_start == (long)vma->vm_mm->context.vdso))
|
|
return "[vdso]";
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Function stubs to prevent linker errors when AT_SYSINFO_EHDR is defined
|
|
*/
|
|
|
|
int in_gate_area_no_mm(unsigned long addr)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
int in_gate_area(struct mm_struct *mm, unsigned long addr)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
|
|
{
|
|
return NULL;
|
|
}
|