[net-next-2.6.git] / arch / sh / kernel / vsyscall / vsyscall.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/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;
}
Commit	Line	Data
19f9a34f	1	/*
58862699	2	* arch/sh/kernel/vsyscall/vsyscall.c
19f9a34f PM	3	*
	4	* Copyright (C) 2006 Paul Mundt
	5	*
	6	* vDSO randomization
	7	* Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar
	8	*
	9	* This file is subject to the terms and conditions of the GNU General Public
	10	* License. See the file "COPYING" in the main directory of this archive
	11	* for more details.
	12	*/
	13	#include <linux/mm.h>
19f9a34f PM	14	#include <linux/kernel.h>
	15	#include <linux/init.h>
	16	#include <linux/gfp.h>
	17	#include <linux/module.h>
	18	#include <linux/elf.h>
f75522ce	19	#include <linux/sched.h>
e06c4e57	20	#include <linux/err.h>
19f9a34f PM	21
	22	/*
	23	* Should the kernel map a VDSO page into processes and pass its
	24	* address down to glibc upon exec()?
	25	*/
	26	unsigned int __read_mostly vdso_enabled = 1;
	27	EXPORT_SYMBOL_GPL(vdso_enabled);
	28
	29	static int __init vdso_setup(char *s)
	30	{
	31	vdso_enabled = simple_strtoul(s, NULL, 0);
	32	return 1;
	33	}
	34	__setup("vdso=", vdso_setup);
	35
	36	/*
	37	* These symbols are defined by vsyscall.o to mark the bounds
	38	* of the ELF DSO images included therein.
	39	*/
	40	extern const char vsyscall_trapa_start, vsyscall_trapa_end;
2affc857	41	static struct page *syscall_pages[1];
19f9a34f PM	42
	43	int __init vsyscall_init(void)
	44	{
2affc857 PM	45	void syscall_page = (void )get_zeroed_page(GFP_ATOMIC);
2affc857 PM	46	syscall_pages[0] = virt_to_page(syscall_page);
19f9a34f PM	47
	48	/*
	49	* XXX: Map this page to a fixmap entry if we get around
	50	* to adding the page to ELF core dumps
	51	*/
	52
	53	memcpy(syscall_page,
	54	&vsyscall_trapa_start,
	55	&vsyscall_trapa_end - &vsyscall_trapa_start);
	56
	57	return 0;
	58	}
	59
19f9a34f	60	/* Setup a VMA at program startup for the vsyscall page */
fc5243d9	61	int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
19f9a34f	62	{
19f9a34f PM	63	struct mm_struct *mm = current->mm;
	64	unsigned long addr;
	65	int ret;
	66
	67	down_write(&mm->mmap_sem);
	68	addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
	69	if (IS_ERR_VALUE(addr)) {
	70	ret = addr;
	71	goto up_fail;
	72	}
	73
2affc857 PM	74	ret = install_special_mapping(mm, addr, PAGE_SIZE,
	75	VM_READ \| VM_EXEC \|
	76	VM_MAYREAD \| VM_MAYWRITE \| VM_MAYEXEC \|
	77	VM_ALWAYSDUMP,
	78	syscall_pages);
	79	if (unlikely(ret))
19f9a34f	80	goto up_fail;
19f9a34f PM	81
	82	current->mm->context.vdso = (void *)addr;
	83
19f9a34f PM	84	up_fail:
	85	up_write(&mm->mmap_sem);
	86	return ret;
	87	}
	88
	89	const char arch_vma_name(struct vm_area_struct vma)
	90	{
	91	if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
	92	return "[vdso]";
	93
	94	return NULL;
	95	}
	96
	97	struct vm_area_struct get_gate_vma(struct task_struct task)
	98	{
	99	return NULL;
	100	}
	101
	102	int in_gate_area(struct task_struct *task, unsigned long address)
	103	{
	104	return 0;
	105	}
	106
	107	int in_gate_area_no_task(unsigned long address)
	108	{
	109	return 0;
	110	}