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/*
* 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.
*
* Copyright (C) 2009, 2010 Cavium Networks, Inc.
*/
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/binfmts.h>
#include <linux/elf.h>
#include <linux/vmalloc.h>
#include <linux/unistd.h>
#include <linux/random.h>
#include <asm/vdso.h>
#include <asm/uasm.h>
#include <asm/processor.h>
/*
* Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
*/
#define __NR_O32_sigreturn 4119
#define __NR_O32_rt_sigreturn 4193
#define __NR_N32_rt_sigreturn 6211
static struct page *vdso_page;
static void __init install_trampoline(u32 *tramp, unsigned int sigreturn)
{
uasm_i_addiu(&tramp, 2, 0, sigreturn); /* li v0, sigreturn */
uasm_i_syscall(&tramp, 0);
}
static int __init init_vdso(void)
{
struct mips_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_trampoline(vdso->rt_signal_trampoline, __NR_rt_sigreturn);
#ifdef CONFIG_32BIT
install_trampoline(vdso->signal_trampoline, __NR_sigreturn);
#else
install_trampoline(vdso->n32_rt_signal_trampoline,
__NR_N32_rt_sigreturn);
install_trampoline(vdso->o32_signal_trampoline, __NR_O32_sigreturn);
install_trampoline(vdso->o32_rt_signal_trampoline,
__NR_O32_rt_sigreturn);
#endif
vunmap(vdso);
return 0;
}
subsys_initcall(init_vdso);
static unsigned long vdso_addr(unsigned long start)
{
unsigned long offset = 0UL;
if (current->flags & PF_RANDOMIZE) {
offset = get_random_int();
offset <<= PAGE_SHIFT;
if (TASK_IS_32BIT_ADDR)
offset &= 0xfffffful;
else
offset &= 0xffffffful;
}
return STACK_TOP + offset;
}
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
int ret;
unsigned long addr;
struct mm_struct *mm = current->mm;
down_write(&mm->mmap_sem);
addr = vdso_addr(mm->start_stack);
addr = get_unmapped_area(NULL, addr, 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,
&vdso_page);
if (ret)
goto up_fail;
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;
}
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