[linux-2.6-block.git] / arch / s390 / kernel / vdso.c

/*
 * vdso setup for s390
 *
 *  Copyright IBM Corp. 2008
 *  Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License (version 2 only)
 * as published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/user.h>
#include <linux/elf.h>
#include <linux/security.h>
#include <linux/bootmem.h>
#include <linux/compat.h>
#include <asm/asm-offsets.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>
#include <asm/mmu.h>
#include <asm/mmu_context.h>
#include <asm/sections.h>
#include <asm/vdso.h>

#if defined(CONFIG_32BIT) || defined(CONFIG_COMPAT)
extern char vdso32_start, vdso32_end;
static void *vdso32_kbase = &vdso32_start;
static unsigned int vdso32_pages;
static struct page **vdso32_pagelist;
#endif

#ifdef CONFIG_64BIT
extern char vdso64_start, vdso64_end;
static void *vdso64_kbase = &vdso64_start;
static unsigned int vdso64_pages;
static struct page **vdso64_pagelist;
#endif /* CONFIG_64BIT */

/*
 * 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;

static int __init vdso_setup(char *s)
{
	unsigned long val;
	int rc;

	rc = 0;
	if (strncmp(s, "on", 3) == 0)
		vdso_enabled = 1;
	else if (strncmp(s, "off", 4) == 0)
		vdso_enabled = 0;
	else {
		rc = strict_strtoul(s, 0, &val);
		vdso_enabled = rc ? 0 : !!val;
	}
	return !rc;
}
__setup("vdso=", vdso_setup);

/*
 * 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;

/*
 * Setup vdso data page.
 */
static void vdso_init_data(struct vdso_data *vd)
{
	vd->ectg_available = user_mode != HOME_SPACE_MODE && test_facility(31);
}

#ifdef CONFIG_64BIT
/*
 * Setup per cpu vdso data page.
 */
static void vdso_init_per_cpu_data(int cpu, struct vdso_per_cpu_data *vpcd)
{
}

/*
 * Allocate/free per cpu vdso data.
 */
#define SEGMENT_ORDER	2

int vdso_alloc_per_cpu(int cpu, struct _lowcore *lowcore)
{
	unsigned long segment_table, page_table, page_frame;
	u32 *psal, *aste;
	int i;

	lowcore->vdso_per_cpu_data = __LC_PASTE;

	if (user_mode == HOME_SPACE_MODE || !vdso_enabled)
		return 0;

	segment_table = __get_free_pages(GFP_KERNEL, SEGMENT_ORDER);
	page_table = get_zeroed_page(GFP_KERNEL | GFP_DMA);
	page_frame = get_zeroed_page(GFP_KERNEL);
	if (!segment_table || !page_table || !page_frame)
		goto out;

	clear_table((unsigned long *) segment_table, _SEGMENT_ENTRY_EMPTY,
		    PAGE_SIZE << SEGMENT_ORDER);
	clear_table((unsigned long *) page_table, _PAGE_TYPE_EMPTY,
		    256*sizeof(unsigned long));

	*(unsigned long *) segment_table = _SEGMENT_ENTRY + page_table;
	*(unsigned long *) page_table = _PAGE_RO + page_frame;

	psal = (u32 *) (page_table + 256*sizeof(unsigned long));
	aste = psal + 32;

	for (i = 4; i < 32; i += 4)
		psal[i] = 0x80000000;

	lowcore->paste[4] = (u32)(addr_t) psal;
	psal[0] = 0x20000000;
	psal[2] = (u32)(addr_t) aste;
	*(unsigned long *) (aste + 2) = segment_table +
		_ASCE_TABLE_LENGTH + _ASCE_USER_BITS + _ASCE_TYPE_SEGMENT;
	aste[4] = (u32)(addr_t) psal;
	lowcore->vdso_per_cpu_data = page_frame;

	vdso_init_per_cpu_data(cpu, (struct vdso_per_cpu_data *) page_frame);
	return 0;

out:
	free_page(page_frame);
	free_page(page_table);
	free_pages(segment_table, SEGMENT_ORDER);
	return -ENOMEM;
}

void vdso_free_per_cpu(int cpu, struct _lowcore *lowcore)
{
	unsigned long segment_table, page_table, page_frame;
	u32 *psal, *aste;

	if (user_mode == HOME_SPACE_MODE || !vdso_enabled)
		return;

	psal = (u32 *)(addr_t) lowcore->paste[4];
	aste = (u32 *)(addr_t) psal[2];
	segment_table = *(unsigned long *)(aste + 2) & PAGE_MASK;
	page_table = *(unsigned long *) segment_table;
	page_frame = *(unsigned long *) page_table;

	free_page(page_frame);
	free_page(page_table);
	free_pages(segment_table, SEGMENT_ORDER);
}

static void __vdso_init_cr5(void *dummy)
{
	unsigned long cr5;

	cr5 = offsetof(struct _lowcore, paste);
	__ctl_load(cr5, 5, 5);
}

static void vdso_init_cr5(void)
{
	if (user_mode != HOME_SPACE_MODE && vdso_enabled)
		on_each_cpu(__vdso_init_cr5, NULL, 1);
}
#endif /* CONFIG_64BIT */

/*
 * This is called from binfmt_elf, we create the special vma for the
 * vDSO and insert it into the mm struct tree
 */
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
	struct mm_struct *mm = current->mm;
	struct page **vdso_pagelist;
	unsigned long vdso_pages;
	unsigned long vdso_base;
	int rc;

	if (!vdso_enabled)
		return 0;
	/*
	 * Only map the vdso for dynamically linked elf binaries.
	 */
	if (!uses_interp)
		return 0;

	vdso_base = mm->mmap_base;
#ifdef CONFIG_64BIT
	vdso_pagelist = vdso64_pagelist;
	vdso_pages = vdso64_pages;
#ifdef CONFIG_COMPAT
	if (is_compat_task()) {
		vdso_pagelist = vdso32_pagelist;
		vdso_pages = vdso32_pages;
	}
#endif
#else
	vdso_pagelist = vdso32_pagelist;
	vdso_pages = vdso32_pages;
#endif

	/*
	 * vDSO has a problem and was disabled, just don't "enable" it for
	 * the process
	 */
	if (vdso_pages == 0)
		return 0;

	current->mm->context.vdso_base = 0;

	/*
	 * pick a base address for the vDSO in process space. We try to put
	 * it at vdso_base which is the "natural" base for it, but we might
	 * fail and end up putting it elsewhere.
	 */
	down_write(&mm->mmap_sem);
	vdso_base = get_unmapped_area(NULL, vdso_base,
				      vdso_pages << PAGE_SHIFT, 0, 0);
	if (IS_ERR_VALUE(vdso_base)) {
		rc = vdso_base;
		goto out_up;
	}

	/*
	 * 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).
	 */
	current->mm->context.vdso_base = vdso_base;

	/*
	 * our vma flags don't have VM_WRITE so by default, the process
	 * isn't allowed to write those pages.
	 * gdb can break that with ptrace interface, and thus trigger COW
	 * on those pages but it's then your responsibility to never do that
	 * on the "data" page of the vDSO or you'll stop getting kernel
	 * updates and your nice userland gettimeofday will be totally dead.
	 * It's fine to use that for setting breakpoints in the vDSO code
	 * pages though
	 *
	 * Make sure the vDSO gets into every core dump.
	 * Dumping its contents makes post-mortem fully interpretable later
	 * without matching up the same kernel and hardware config to see
	 * what PC values meant.
	 */
	rc = install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
				     VM_READ|VM_EXEC|
				     VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
				     VM_ALWAYSDUMP,
				     vdso_pagelist);
	if (rc)
		current->mm->context.vdso_base = 0;
out_up:
	up_write(&mm->mmap_sem);
	return rc;
}

const char *arch_vma_name(struct vm_area_struct *vma)
{
	if (vma->vm_mm && vma->vm_start == vma->vm_mm->context.vdso_base)
		return "[vdso]";
	return NULL;
}

static int __init vdso_init(void)
{
	int i;

	if (!vdso_enabled)
		return 0;
	vdso_init_data(vdso_data);
#if defined(CONFIG_32BIT) || defined(CONFIG_COMPAT)
	/* Calculate the size of the 32 bit vDSO */
	vdso32_pages = ((&vdso32_end - &vdso32_start
			 + PAGE_SIZE - 1) >> PAGE_SHIFT) + 1;

	/* Make sure pages are in the correct state */
	vdso32_pagelist = kzalloc(sizeof(struct page *) * (vdso32_pages + 1),
				  GFP_KERNEL);
	BUG_ON(vdso32_pagelist == NULL);
	for (i = 0; i < vdso32_pages - 1; i++) {
		struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE);
		ClearPageReserved(pg);
		get_page(pg);
		vdso32_pagelist[i] = pg;
	}
	vdso32_pagelist[vdso32_pages - 1] = virt_to_page(vdso_data);
	vdso32_pagelist[vdso32_pages] = NULL;
#endif

#ifdef CONFIG_64BIT
	/* Calculate the size of the 64 bit vDSO */
	vdso64_pages = ((&vdso64_end - &vdso64_start
			 + PAGE_SIZE - 1) >> PAGE_SHIFT) + 1;

	/* Make sure pages are in the correct state */
	vdso64_pagelist = kzalloc(sizeof(struct page *) * (vdso64_pages + 1),
				  GFP_KERNEL);
	BUG_ON(vdso64_pagelist == NULL);
	for (i = 0; i < vdso64_pages - 1; i++) {
		struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE);
		ClearPageReserved(pg);
		get_page(pg);
		vdso64_pagelist[i] = pg;
	}
	vdso64_pagelist[vdso64_pages - 1] = virt_to_page(vdso_data);
	vdso64_pagelist[vdso64_pages] = NULL;
#ifndef CONFIG_SMP
	if (vdso_alloc_per_cpu(0, &S390_lowcore))
		BUG();
#endif
	vdso_init_cr5();
#endif /* CONFIG_64BIT */

	get_page(virt_to_page(vdso_data));

	smp_wmb();

	return 0;
}
arch_initcall(vdso_init);

int in_gate_area_no_task(unsigned long addr)
{
	return 0;
}

int in_gate_area(struct task_struct *task, unsigned long addr)
{
	return 0;
}

struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
{
	return NULL;
}
Commit	Line	Data
b020632e MS	1	/*
	2	* vdso setup for s390
	3	*
	4	* Copyright IBM Corp. 2008
	5	* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License (version 2 only)
	9	* as published by the Free Software Foundation.
	10	*/
	11
	12	#include <linux/module.h>
	13	#include <linux/errno.h>
	14	#include <linux/sched.h>
	15	#include <linux/kernel.h>
	16	#include <linux/mm.h>
	17	#include <linux/smp.h>
	18	#include <linux/stddef.h>
	19	#include <linux/unistd.h>
	20	#include <linux/slab.h>
	21	#include <linux/user.h>
	22	#include <linux/elf.h>
	23	#include <linux/security.h>
	24	#include <linux/bootmem.h>
7757591a	25	#include <linux/compat.h>
cbb870c8	26	#include <asm/asm-offsets.h>
b020632e MS	27	#include <asm/pgtable.h>
	28	#include <asm/system.h>
	29	#include <asm/processor.h>
	30	#include <asm/mmu.h>
	31	#include <asm/mmu_context.h>
	32	#include <asm/sections.h>
	33	#include <asm/vdso.h>
	34
b020632e MS	35	#if defined(CONFIG_32BIT) \|\| defined(CONFIG_COMPAT)
	36	extern char vdso32_start, vdso32_end;
	37	static void *vdso32_kbase = &vdso32_start;
	38	static unsigned int vdso32_pages;
	39	static struct page **vdso32_pagelist;
	40	#endif
	41
	42	#ifdef CONFIG_64BIT
	43	extern char vdso64_start, vdso64_end;
	44	static void *vdso64_kbase = &vdso64_start;
	45	static unsigned int vdso64_pages;
	46	static struct page **vdso64_pagelist;
	47	#endif /* CONFIG_64BIT */
	48
	49	/*
	50	* Should the kernel map a VDSO page into processes and pass its
	51	* address down to glibc upon exec()?
	52	*/
	53	unsigned int __read_mostly vdso_enabled = 1;
	54
	55	static int __init vdso_setup(char *s)
	56	{
7aa79f94 MS	57	unsigned long val;
	58	int rc;
	59
	60	rc = 0;
	61	if (strncmp(s, "on", 3) == 0)
	62	vdso_enabled = 1;
	63	else if (strncmp(s, "off", 4) == 0)
	64	vdso_enabled = 0;
	65	else {
	66	rc = strict_strtoul(s, 0, &val);
	67	vdso_enabled = rc ? 0 : !!val;
	68	}
	69	return !rc;
b020632e MS	70	}
	71	__setup("vdso=", vdso_setup);
	72
	73	/*
	74	* The vdso data page
	75	*/
	76	static union {
	77	struct vdso_data data;
	78	u8 page[PAGE_SIZE];
abe1ee3a	79	} vdso_data_store __page_aligned_data;
b020632e MS	80	struct vdso_data *vdso_data = &vdso_data_store.data;
b020632e MS	81
c742b31c MS	82	/*
	83	* Setup vdso data page.
	84	*/
	85	static void vdso_init_data(struct vdso_data *vd)
	86	{
14375bc4	87	vd->ectg_available = user_mode != HOME_SPACE_MODE && test_facility(31);
c742b31c MS	88	}
	89
	90	#ifdef CONFIG_64BIT
	91	/*
	92	* Setup per cpu vdso data page.
	93	*/
	94	static void vdso_init_per_cpu_data(int cpu, struct vdso_per_cpu_data *vpcd)
	95	{
	96	}
	97
	98	/*
	99	* Allocate/free per cpu vdso data.
	100	*/
c742b31c	101	#define SEGMENT_ORDER 2
c742b31c MS	102
	103	int vdso_alloc_per_cpu(int cpu, struct _lowcore *lowcore)
	104	{
	105	unsigned long segment_table, page_table, page_frame;
	106	u32 psal, aste;
	107	int i;
	108
	109	lowcore->vdso_per_cpu_data = __LC_PASTE;
	110
b11b5334	111	if (user_mode == HOME_SPACE_MODE \|\| !vdso_enabled)
c742b31c MS	112	return 0;
	113
	114	segment_table = __get_free_pages(GFP_KERNEL, SEGMENT_ORDER);
	115	page_table = get_zeroed_page(GFP_KERNEL \| GFP_DMA);
	116	page_frame = get_zeroed_page(GFP_KERNEL);
	117	if (!segment_table \|\| !page_table \|\| !page_frame)
	118	goto out;
	119
	120	clear_table((unsigned long *) segment_table, _SEGMENT_ENTRY_EMPTY,
	121	PAGE_SIZE << SEGMENT_ORDER);
	122	clear_table((unsigned long *) page_table, _PAGE_TYPE_EMPTY,
	123	256*sizeof(unsigned long));
	124
	125	(unsigned long ) segment_table = _SEGMENT_ENTRY + page_table;
	126	(unsigned long ) page_table = _PAGE_RO + page_frame;
	127
	128	psal = (u32 ) (page_table + 256sizeof(unsigned long));
	129	aste = psal + 32;
	130
	131	for (i = 4; i < 32; i += 4)
	132	psal[i] = 0x80000000;
	133
	134	lowcore->paste[4] = (u32)(addr_t) psal;
	135	psal[0] = 0x20000000;
	136	psal[2] = (u32)(addr_t) aste;
	137	(unsigned long ) (aste + 2) = segment_table +
	138	_ASCE_TABLE_LENGTH + _ASCE_USER_BITS + _ASCE_TYPE_SEGMENT;
	139	aste[4] = (u32)(addr_t) psal;
	140	lowcore->vdso_per_cpu_data = page_frame;
	141
	142	vdso_init_per_cpu_data(cpu, (struct vdso_per_cpu_data *) page_frame);
	143	return 0;
	144
	145	out:
	146	free_page(page_frame);
	147	free_page(page_table);
	148	free_pages(segment_table, SEGMENT_ORDER);
	149	return -ENOMEM;
	150	}
	151
c742b31c MS	152	void vdso_free_per_cpu(int cpu, struct _lowcore *lowcore)
	153	{
	154	unsigned long segment_table, page_table, page_frame;
	155	u32 psal, aste;
	156
b11b5334	157	if (user_mode == HOME_SPACE_MODE \|\| !vdso_enabled)
c742b31c MS	158	return;
	159
	160	psal = (u32 *)(addr_t) lowcore->paste[4];
	161	aste = (u32 *)(addr_t) psal[2];
	162	segment_table = (unsigned long )(aste + 2) & PAGE_MASK;
	163	page_table = (unsigned long ) segment_table;
	164	page_frame = (unsigned long ) page_table;
	165
	166	free_page(page_frame);
	167	free_page(page_table);
	168	free_pages(segment_table, SEGMENT_ORDER);
	169	}
c742b31c MS	170
	171	static void __vdso_init_cr5(void *dummy)
	172	{
	173	unsigned long cr5;
	174
	175	cr5 = offsetof(struct _lowcore, paste);
	176	__ctl_load(cr5, 5, 5);
	177	}
	178
	179	static void vdso_init_cr5(void)
	180	{
b11b5334	181	if (user_mode != HOME_SPACE_MODE && vdso_enabled)
c742b31c MS	182	on_each_cpu(__vdso_init_cr5, NULL, 1);
	183	}
	184	#endif /* CONFIG_64BIT */
	185
b020632e MS	186	/*
	187	* This is called from binfmt_elf, we create the special vma for the
	188	* vDSO and insert it into the mm struct tree
	189	*/
	190	int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
	191	{
	192	struct mm_struct *mm = current->mm;
	193	struct page **vdso_pagelist;
	194	unsigned long vdso_pages;
	195	unsigned long vdso_base;
	196	int rc;
	197
	198	if (!vdso_enabled)
	199	return 0;
	200	/*
	201	* Only map the vdso for dynamically linked elf binaries.
	202	*/
	203	if (!uses_interp)
	204	return 0;
	205
	206	vdso_base = mm->mmap_base;
	207	#ifdef CONFIG_64BIT
	208	vdso_pagelist = vdso64_pagelist;
	209	vdso_pages = vdso64_pages;
	210	#ifdef CONFIG_COMPAT
7757591a	211	if (is_compat_task()) {
b020632e MS	212	vdso_pagelist = vdso32_pagelist;
	213	vdso_pages = vdso32_pages;
	214	}
	215	#endif
	216	#else
	217	vdso_pagelist = vdso32_pagelist;
	218	vdso_pages = vdso32_pages;
	219	#endif
	220
	221	/*
	222	* vDSO has a problem and was disabled, just don't "enable" it for
	223	* the process
	224	*/
	225	if (vdso_pages == 0)
	226	return 0;
	227
	228	current->mm->context.vdso_base = 0;
	229
	230	/*
	231	* pick a base address for the vDSO in process space. We try to put
	232	* it at vdso_base which is the "natural" base for it, but we might
	233	* fail and end up putting it elsewhere.
	234	*/
	235	down_write(&mm->mmap_sem);
	236	vdso_base = get_unmapped_area(NULL, vdso_base,
	237	vdso_pages << PAGE_SHIFT, 0, 0);
	238	if (IS_ERR_VALUE(vdso_base)) {
	239	rc = vdso_base;
	240	goto out_up;
	241	}
	242
930e44fb HC	243	/*
	244	* Put vDSO base into mm struct. We need to do this before calling
	245	* install_special_mapping or the perf counter mmap tracking code
	246	* will fail to recognise it as a vDSO (since arch_vma_name fails).
	247	*/
	248	current->mm->context.vdso_base = vdso_base;
	249
b020632e MS	250	/*
	251	* our vma flags don't have VM_WRITE so by default, the process
	252	* isn't allowed to write those pages.
	253	* gdb can break that with ptrace interface, and thus trigger COW
	254	* on those pages but it's then your responsibility to never do that
	255	* on the "data" page of the vDSO or you'll stop getting kernel
	256	* updates and your nice userland gettimeofday will be totally dead.
	257	* It's fine to use that for setting breakpoints in the vDSO code
	258	* pages though
	259	*
	260	* Make sure the vDSO gets into every core dump.
	261	* Dumping its contents makes post-mortem fully interpretable later
	262	* without matching up the same kernel and hardware config to see
	263	* what PC values meant.
	264	*/
	265	rc = install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT,
	266	VM_READ\|VM_EXEC\|
	267	VM_MAYREAD\|VM_MAYWRITE\|VM_MAYEXEC\|
	268	VM_ALWAYSDUMP,
	269	vdso_pagelist);
	270	if (rc)
930e44fb	271	current->mm->context.vdso_base = 0;
b020632e MS	272	out_up:
	273	up_write(&mm->mmap_sem);
	274	return rc;
	275	}
	276
	277	const char arch_vma_name(struct vm_area_struct vma)
	278	{
	279	if (vma->vm_mm && vma->vm_start == vma->vm_mm->context.vdso_base)
	280	return "[vdso]";
	281	return NULL;
	282	}
	283
	284	static int __init vdso_init(void)
	285	{
	286	int i;
	287
c742b31c MS	288	if (!vdso_enabled)
	289	return 0;
	290	vdso_init_data(vdso_data);
b020632e MS	291	#if defined(CONFIG_32BIT) \|\| defined(CONFIG_COMPAT)
	292	/* Calculate the size of the 32 bit vDSO */
	293	vdso32_pages = ((&vdso32_end - &vdso32_start
	294	+ PAGE_SIZE - 1) >> PAGE_SHIFT) + 1;
	295
	296	/* Make sure pages are in the correct state */
	297	vdso32_pagelist = kzalloc(sizeof(struct page ) (vdso32_pages + 1),
	298	GFP_KERNEL);
	299	BUG_ON(vdso32_pagelist == NULL);
	300	for (i = 0; i < vdso32_pages - 1; i++) {
	301	struct page pg = virt_to_page(vdso32_kbase + iPAGE_SIZE);
	302	ClearPageReserved(pg);
	303	get_page(pg);
	304	vdso32_pagelist[i] = pg;
	305	}
	306	vdso32_pagelist[vdso32_pages - 1] = virt_to_page(vdso_data);
	307	vdso32_pagelist[vdso32_pages] = NULL;
	308	#endif
	309
	310	#ifdef CONFIG_64BIT
	311	/* Calculate the size of the 64 bit vDSO */
	312	vdso64_pages = ((&vdso64_end - &vdso64_start
	313	+ PAGE_SIZE - 1) >> PAGE_SHIFT) + 1;
	314
	315	/* Make sure pages are in the correct state */
	316	vdso64_pagelist = kzalloc(sizeof(struct page ) (vdso64_pages + 1),
	317	GFP_KERNEL);
	318	BUG_ON(vdso64_pagelist == NULL);
	319	for (i = 0; i < vdso64_pages - 1; i++) {
	320	struct page pg = virt_to_page(vdso64_kbase + iPAGE_SIZE);
	321	ClearPageReserved(pg);
	322	get_page(pg);
	323	vdso64_pagelist[i] = pg;
	324	}
	325	vdso64_pagelist[vdso64_pages - 1] = virt_to_page(vdso_data);
	326	vdso64_pagelist[vdso64_pages] = NULL;
c742b31c	327	#ifndef CONFIG_SMP
81ffa041 HC	328	if (vdso_alloc_per_cpu(0, &S390_lowcore))
81ffa041 HC	329	BUG();
c742b31c MS	330	#endif
c742b31c MS	331	vdso_init_cr5();
b020632e MS	332	#endif /* CONFIG_64BIT */
	333
	334	get_page(virt_to_page(vdso_data));
	335
	336	smp_wmb();
	337
	338	return 0;
	339	}
	340	arch_initcall(vdso_init);
	341
	342	int in_gate_area_no_task(unsigned long addr)
	343	{
	344	return 0;
	345	}
	346
	347	int in_gate_area(struct task_struct *task, unsigned long addr)
	348	{
	349	return 0;
	350	}
	351
	352	struct vm_area_struct get_gate_vma(struct task_struct tsk)
	353	{
	354	return NULL;
	355	}