mirror of
https://github.com/torvalds/linux.git
synced 2024-11-16 09:02:00 +00:00
e1858b2a21
Code Aurora Forum (CAF) is becoming a part of Linux Foundation Labs. Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
101 lines
2.5 KiB
C
101 lines
2.5 KiB
C
/*
|
|
* vDSO implementation for Hexagon
|
|
*
|
|
* Copyright (c) 2011, The Linux Foundation. All rights reserved.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 and
|
|
* only 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, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
|
|
* 02110-1301, USA.
|
|
*/
|
|
|
|
#include <linux/err.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/vmalloc.h>
|
|
#include <linux/binfmts.h>
|
|
|
|
#include <asm/vdso.h>
|
|
|
|
static struct page *vdso_page;
|
|
|
|
/* Create a vDSO page holding the signal trampoline.
|
|
* We want this for a non-executable stack.
|
|
*/
|
|
static int __init vdso_init(void)
|
|
{
|
|
struct hexagon_vdso *vdso;
|
|
|
|
vdso_page = alloc_page(GFP_KERNEL);
|
|
if (!vdso_page)
|
|
panic("Cannot allocate vdso");
|
|
|
|
vdso = vmap(&vdso_page, 1, 0, PAGE_KERNEL);
|
|
if (!vdso)
|
|
panic("Cannot map vdso");
|
|
clear_page(vdso);
|
|
|
|
/* Install the signal trampoline; currently looks like this:
|
|
* r6 = #__NR_rt_sigreturn;
|
|
* trap0(#1);
|
|
*/
|
|
vdso->rt_signal_trampoline[0] = __rt_sigtramp_template[0];
|
|
vdso->rt_signal_trampoline[1] = __rt_sigtramp_template[1];
|
|
|
|
vunmap(vdso);
|
|
|
|
return 0;
|
|
}
|
|
arch_initcall(vdso_init);
|
|
|
|
/*
|
|
* Called from binfmt_elf. Create a VMA for the vDSO page.
|
|
*/
|
|
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
|
|
{
|
|
int ret;
|
|
unsigned long vdso_base;
|
|
struct mm_struct *mm = current->mm;
|
|
|
|
down_write(&mm->mmap_sem);
|
|
|
|
/* Try to get it loaded right near ld.so/glibc. */
|
|
vdso_base = STACK_TOP;
|
|
|
|
vdso_base = get_unmapped_area(NULL, vdso_base, PAGE_SIZE, 0, 0);
|
|
if (IS_ERR_VALUE(vdso_base)) {
|
|
ret = vdso_base;
|
|
goto up_fail;
|
|
}
|
|
|
|
/* MAYWRITE to allow gdb to COW and set breakpoints. */
|
|
ret = install_special_mapping(mm, vdso_base, PAGE_SIZE,
|
|
VM_READ|VM_EXEC|
|
|
VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
|
|
&vdso_page);
|
|
|
|
if (ret)
|
|
goto up_fail;
|
|
|
|
mm->context.vdso = (void *)vdso_base;
|
|
|
|
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;
|
|
}
|