112 lines
2.4 KiB
C
112 lines
2.4 KiB
C
|
/*
|
||
|
|
* arch/sh/kernel/vsyscall/vsyscall.c
|
||
|
|
*
|
||
|
|
* Copyright (C) 2006 Paul Mundt
|
||
|
|
*
|
||
|
|
* vDSO randomization
|
||
|
|
* Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar
|
||
|
|
*
|
||
|
|
* This file is subject to the terms and conditions of the GNU General Public
|
||
|
|
* License. See the file "COPYING" in the main directory of this archive
|
||
|
|
* for more details.
|
||
|
|
*/
|
||
|
|
#include <linux/mm.h>
|
||
|
|
#include <linux/slab.h>
|
||
|
|
#include <linux/kernel.h>
|
||
|
|
#include <linux/init.h>
|
||
|
|
#include <linux/gfp.h>
|
||
|
|
#include <linux/module.h>
|
||
|
|
#include <linux/elf.h>
|
||
|
|
#include <linux/sched.h>
|
||
|
|
#include <linux/err.h>
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Should the kernel map a VDSO page into processes and pass its
|
||
|
|
* address down to glibc upon exec()?
|
||
|
|
*/
|
||
|
|
unsigned int __read_mostly vdso_enabled = 1;
|
||
|
|
EXPORT_SYMBOL_GPL(vdso_enabled);
|
||
|
|
|
||
|
|
static int __init vdso_setup(char *s)
|
||
|
|
{
|
||
|
|
vdso_enabled = simple_strtoul(s, NULL, 0);
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
__setup("vdso=", vdso_setup);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* These symbols are defined by vsyscall.o to mark the bounds
|
||
|
|
* of the ELF DSO images included therein.
|
||
|
|
*/
|
||
|
|
extern const char vsyscall_trapa_start, vsyscall_trapa_end;
|
||
|
|
static struct page *syscall_pages[1];
|
||
|
|
|
||
|
|
int __init vsyscall_init(void)
|
||
|
|
{
|
||
|
|
void *syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);
|
||
|
|
syscall_pages[0] = virt_to_page(syscall_page);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* XXX: Map this page to a fixmap entry if we get around
|
||
|
|
* to adding the page to ELF core dumps
|
||
|
|
*/
|
||
|
|
|
||
|
|
memcpy(syscall_page,
|
||
|
|
&vsyscall_trapa_start,
|
||
|
|
&vsyscall_trapa_end - &vsyscall_trapa_start);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Setup a VMA at program startup for the vsyscall page */
|
||
|
|
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
|
||
|
|
{
|
||
|
|
struct mm_struct *mm = current->mm;
|
||
|
|
unsigned long addr;
|
||
|
|
int ret;
|
||
|
|
|
||
|
|
down_write(&mm->mmap_sem);
|
||
|
|
addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
|
||
|
|
if (IS_ERR_VALUE(addr)) {
|
||
|
|
ret = addr;
|
||
|
|
goto up_fail;
|
||
|
|
}
|
||
|
|
|
||
|
|
ret = install_special_mapping(mm, addr, PAGE_SIZE,
|
||
|
|
VM_READ | VM_EXEC |
|
||
|
|
VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC |
|
||
|
|
VM_ALWAYSDUMP,
|
||
|
|
syscall_pages);
|
||
|
|
if (unlikely(ret))
|
||
|
|
goto up_fail;
|
||
|
|
|
||
|
|
current->mm->context.vdso = (void *)addr;
|
||
|
|
|
||
|
|
up_fail:
|
||
|
|
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;
|
||
|
|
}
|
||
|
|
|
||
|
|
struct vm_area_struct *get_gate_vma(struct task_struct *task)
|
||
|
|
{
|
||
|
|
return NULL;
|
||
|
|
}
|
||
|
|
|
||
|
|
int in_gate_area(struct task_struct *task, unsigned long address)
|
||
|
|
{
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
int in_gate_area_no_task(unsigned long address)
|
||
|
|
{
|
||
|
|
return 0;
|
||
|
|
}
|