[deliverable/linux.git] / arch / x86 / kernel / vsyscall_64.c

/*
 *  Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
 *  Copyright 2003 Andi Kleen, SuSE Labs.
 *
 *  Thanks to hpa@transmeta.com for some useful hint.
 *  Special thanks to Ingo Molnar for his early experience with
 *  a different vsyscall implementation for Linux/IA32 and for the name.
 *
 *  vsyscall 1 is located at -10Mbyte, vsyscall 2 is located
 *  at virtual address -10Mbyte+1024bytes etc... There are at max 4
 *  vsyscalls. One vsyscall can reserve more than 1 slot to avoid
 *  jumping out of line if necessary. We cannot add more with this
 *  mechanism because older kernels won't return -ENOSYS.
 *  If we want more than four we need a vDSO.
 *
 *  Note: the concept clashes with user mode linux. If you use UML and
 *  want per guest time just set the kernel.vsyscall64 sysctl to 0.
 */

/* Disable profiling for userspace code: */
#define DISABLE_BRANCH_PROFILING

#include <linux/time.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/seqlock.h>
#include <linux/jiffies.h>
#include <linux/sysctl.h>
#include <linux/clocksource.h>
#include <linux/getcpu.h>
#include <linux/cpu.h>
#include <linux/smp.h>
#include <linux/notifier.h>

#include <asm/vsyscall.h>
#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/unistd.h>
#include <asm/fixmap.h>
#include <asm/errno.h>
#include <asm/io.h>
#include <asm/segment.h>
#include <asm/desc.h>
#include <asm/topology.h>
#include <asm/vgtod.h>

#define __vsyscall(nr) \
		__attribute__ ((unused, __section__(".vsyscall_" #nr))) notrace
#define __syscall_clobber "r11","cx","memory"

/*
 * vsyscall_gtod_data contains data that is :
 * - readonly from vsyscalls
 * - written by timer interrupt or systcl (/proc/sys/kernel/vsyscall64)
 * Try to keep this structure as small as possible to avoid cache line ping pongs
 */
int __vgetcpu_mode __section_vgetcpu_mode;

struct vsyscall_gtod_data __vsyscall_gtod_data __section_vsyscall_gtod_data =
{
	.lock = SEQLOCK_UNLOCKED,
	.sysctl_enabled = 1,
};

void update_vsyscall_tz(void)
{
	unsigned long flags;

	write_seqlock_irqsave(&vsyscall_gtod_data.lock, flags);
	/* sys_tz has changed */
	vsyscall_gtod_data.sys_tz = sys_tz;
	write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags);
}

void update_vsyscall(struct timespec *wall_time, struct clocksource *clock)
{
	unsigned long flags;

	write_seqlock_irqsave(&vsyscall_gtod_data.lock, flags);
	/* copy vsyscall data */
	vsyscall_gtod_data.clock.vread = clock->vread;
	vsyscall_gtod_data.clock.cycle_last = clock->cycle_last;
	vsyscall_gtod_data.clock.mask = clock->mask;
	vsyscall_gtod_data.clock.mult = clock->mult;
	vsyscall_gtod_data.clock.shift = clock->shift;
	vsyscall_gtod_data.wall_time_sec = wall_time->tv_sec;
	vsyscall_gtod_data.wall_time_nsec = wall_time->tv_nsec;
	vsyscall_gtod_data.wall_to_monotonic = wall_to_monotonic;
	write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags);
}

/* RED-PEN may want to readd seq locking, but then the variable should be
 * write-once.
 */
static __always_inline void do_get_tz(struct timezone * tz)
{
	*tz = __vsyscall_gtod_data.sys_tz;
}

static __always_inline int gettimeofday(struct timeval *tv, struct timezone *tz)
{
	int ret;
	asm volatile("syscall"
		: "=a" (ret)
		: "0" (__NR_gettimeofday),"D" (tv),"S" (tz)
		: __syscall_clobber );
	return ret;
}

static __always_inline long time_syscall(long *t)
{
	long secs;
	asm volatile("syscall"
		: "=a" (secs)
		: "0" (__NR_time),"D" (t) : __syscall_clobber);
	return secs;
}

static __always_inline void do_vgettimeofday(struct timeval * tv)
{
	cycle_t now, base, mask, cycle_delta;
	unsigned seq;
	unsigned long mult, shift, nsec;
	cycle_t (*vread)(void);
	do {
		seq = read_seqbegin(&__vsyscall_gtod_data.lock);

		vread = __vsyscall_gtod_data.clock.vread;
		if (unlikely(!__vsyscall_gtod_data.sysctl_enabled || !vread)) {
			gettimeofday(tv,NULL);
			return;
		}

		now = vread();
		base = __vsyscall_gtod_data.clock.cycle_last;
		mask = __vsyscall_gtod_data.clock.mask;
		mult = __vsyscall_gtod_data.clock.mult;
		shift = __vsyscall_gtod_data.clock.shift;

		tv->tv_sec = __vsyscall_gtod_data.wall_time_sec;
		nsec = __vsyscall_gtod_data.wall_time_nsec;
	} while (read_seqretry(&__vsyscall_gtod_data.lock, seq));

	/* calculate interval: */
	cycle_delta = (now - base) & mask;
	/* convert to nsecs: */
	nsec += (cycle_delta * mult) >> shift;

	while (nsec >= NSEC_PER_SEC) {
		tv->tv_sec += 1;
		nsec -= NSEC_PER_SEC;
	}
	tv->tv_usec = nsec / NSEC_PER_USEC;
}

int __vsyscall(0) vgettimeofday(struct timeval * tv, struct timezone * tz)
{
	if (tv)
		do_vgettimeofday(tv);
	if (tz)
		do_get_tz(tz);
	return 0;
}

/* This will break when the xtime seconds get inaccurate, but that is
 * unlikely */
time_t __vsyscall(1) vtime(time_t *t)
{
	struct timeval tv;
	time_t result;
	if (unlikely(!__vsyscall_gtod_data.sysctl_enabled))
		return time_syscall(t);

	vgettimeofday(&tv, NULL);
	result = tv.tv_sec;
	if (t)
		*t = result;
	return result;
}

/* Fast way to get current CPU and node.
   This helps to do per node and per CPU caches in user space.
   The result is not guaranteed without CPU affinity, but usually
   works out because the scheduler tries to keep a thread on the same
   CPU.

   tcache must point to a two element sized long array.
   All arguments can be NULL. */
long __vsyscall(2)
vgetcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *tcache)
{
	unsigned int p;
	unsigned long j = 0;

	/* Fast cache - only recompute value once per jiffies and avoid
	   relatively costly rdtscp/cpuid otherwise.
	   This works because the scheduler usually keeps the process
	   on the same CPU and this syscall doesn't guarantee its
	   results anyways.
	   We do this here because otherwise user space would do it on
	   its own in a likely inferior way (no access to jiffies).
	   If you don't like it pass NULL. */
	if (tcache && tcache->blob[0] == (j = __jiffies)) {
		p = tcache->blob[1];
	} else if (__vgetcpu_mode == VGETCPU_RDTSCP) {
		/* Load per CPU data from RDTSCP */
		native_read_tscp(&p);
	} else {
		/* Load per CPU data from GDT */
		asm("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG));
	}
	if (tcache) {
		tcache->blob[0] = j;
		tcache->blob[1] = p;
	}
	if (cpu)
		*cpu = p & 0xfff;
	if (node)
		*node = p >> 12;
	return 0;
}

static long __vsyscall(3) venosys_1(void)
{
	return -ENOSYS;
}

#ifdef CONFIG_SYSCTL

static int
vsyscall_sysctl_change(ctl_table *ctl, int write, struct file * filp,
		       void __user *buffer, size_t *lenp, loff_t *ppos)
{
	return proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
}

static ctl_table kernel_table2[] = {
	{ .procname = "vsyscall64",
	  .data = &vsyscall_gtod_data.sysctl_enabled, .maxlen = sizeof(int),
	  .mode = 0644,
	  .proc_handler = vsyscall_sysctl_change },
	{}
};

static ctl_table kernel_root_table2[] = {
	{ .ctl_name = CTL_KERN, .procname = "kernel", .mode = 0555,
	  .child = kernel_table2 },
	{}
};
#endif

/* Assume __initcall executes before all user space. Hopefully kmod
   doesn't violate that. We'll find out if it does. */
static void __cpuinit vsyscall_set_cpu(int cpu)
{
	unsigned long d;
	unsigned long node = 0;
#ifdef CONFIG_NUMA
	node = cpu_to_node(cpu);
#endif
	if (cpu_has(&cpu_data(cpu), X86_FEATURE_RDTSCP))
		write_rdtscp_aux((node << 12) | cpu);

	/* Store cpu number in limit so that it can be loaded quickly
	   in user space in vgetcpu.
	   12 bits for the CPU and 8 bits for the node. */
	d = 0x0f40000000000ULL;
	d |= cpu;
	d |= (node & 0xf) << 12;
	d |= (node >> 4) << 48;
	write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_PER_CPU, &d, DESCTYPE_S);
}

static void __cpuinit cpu_vsyscall_init(void *arg)
{
	/* preemption should be already off */
	vsyscall_set_cpu(raw_smp_processor_id());
}

static int __cpuinit
cpu_vsyscall_notifier(struct notifier_block *n, unsigned long action, void *arg)
{
	long cpu = (long)arg;
	if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN)
		smp_call_function_single(cpu, cpu_vsyscall_init, NULL, 1);
	return NOTIFY_DONE;
}

void __init map_vsyscall(void)
{
	extern char __vsyscall_0;
	unsigned long physaddr_page0 = __pa_symbol(&__vsyscall_0);

	/* Note that VSYSCALL_MAPPED_PAGES must agree with the code below. */
	__set_fixmap(VSYSCALL_FIRST_PAGE, physaddr_page0, PAGE_KERNEL_VSYSCALL);
}

static int __init vsyscall_init(void)
{
	BUG_ON(((unsigned long) &vgettimeofday !=
			VSYSCALL_ADDR(__NR_vgettimeofday)));
	BUG_ON((unsigned long) &vtime != VSYSCALL_ADDR(__NR_vtime));
	BUG_ON((VSYSCALL_ADDR(0) != __fix_to_virt(VSYSCALL_FIRST_PAGE)));
	BUG_ON((unsigned long) &vgetcpu != VSYSCALL_ADDR(__NR_vgetcpu));
#ifdef CONFIG_SYSCTL
	register_sysctl_table(kernel_root_table2);
#endif
	on_each_cpu(cpu_vsyscall_init, NULL, 1);
	hotcpu_notifier(cpu_vsyscall_notifier, 0);
	return 0;
}

__initcall(vsyscall_init);
Commit	Line	Data
1da177e4	1	/*
1da177e4 LT	2	* Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
	3	* Copyright 2003 Andi Kleen, SuSE Labs.
	4	*
	5	* Thanks to hpa@transmeta.com for some useful hint.
	6	* Special thanks to Ingo Molnar for his early experience with
	7	* a different vsyscall implementation for Linux/IA32 and for the name.
	8	*
	9	* vsyscall 1 is located at -10Mbyte, vsyscall 2 is located
	10	* at virtual address -10Mbyte+1024bytes etc... There are at max 4
	11	* vsyscalls. One vsyscall can reserve more than 1 slot to avoid
	12	* jumping out of line if necessary. We cannot add more with this
	13	* mechanism because older kernels won't return -ENOSYS.
	14	* If we want more than four we need a vDSO.
	15	*
	16	* Note: the concept clashes with user mode linux. If you use UML and
	17	* want per guest time just set the kernel.vsyscall64 sysctl to 0.
	18	*/
	19
2b7d0390	20	/* Disable profiling for userspace code: */
2ed84eeb	21	#define DISABLE_BRANCH_PROFILING
1f0d69a9	22
1da177e4 LT	23	#include <linux/time.h>
	24	#include <linux/init.h>
	25	#include <linux/kernel.h>
	26	#include <linux/timer.h>
	27	#include <linux/seqlock.h>
	28	#include <linux/jiffies.h>
	29	#include <linux/sysctl.h>
7460ed28	30	#include <linux/clocksource.h>
c08c8205	31	#include <linux/getcpu.h>
8c131af1 AK	32	#include <linux/cpu.h>
	33	#include <linux/smp.h>
	34	#include <linux/notifier.h>
1da177e4 LT	35
	36	#include <asm/vsyscall.h>
	37	#include <asm/pgtable.h>
	38	#include <asm/page.h>
7460ed28	39	#include <asm/unistd.h>
1da177e4 LT	40	#include <asm/fixmap.h>
	41	#include <asm/errno.h>
	42	#include <asm/io.h>
c08c8205 VP	43	#include <asm/segment.h>
	44	#include <asm/desc.h>
	45	#include <asm/topology.h>
2aae950b	46	#include <asm/vgtod.h>
1da177e4	47
23adec55 SR	48	#define __vsyscall(nr) \
23adec55 SR	49	__attribute__ ((unused, __section__(".vsyscall_" #nr))) notrace
65ea5b03	50	#define __syscall_clobber "r11","cx","memory"
1da177e4	51
c8118c6c ED	52	/*
	53	* vsyscall_gtod_data contains data that is :
	54	* - readonly from vsyscalls
676b1855	55	* - written by timer interrupt or systcl (/proc/sys/kernel/vsyscall64)
c8118c6c ED	56	* Try to keep this structure as small as possible to avoid cache line ping pongs
c8118c6c ED	57	*/
c08c8205	58	int __vgetcpu_mode __section_vgetcpu_mode;
1da177e4	59
2aae950b	60	struct vsyscall_gtod_data __vsyscall_gtod_data __section_vsyscall_gtod_data =
1da177e4	61	{
7460ed28	62	.lock = SEQLOCK_UNLOCKED,
	63	.sysctl_enabled = 1,
	64	};
1da177e4	65
2c622148 TB	66	void update_vsyscall_tz(void)
	67	{
	68	unsigned long flags;
	69
	70	write_seqlock_irqsave(&vsyscall_gtod_data.lock, flags);
	71	/* sys_tz has changed */
	72	vsyscall_gtod_data.sys_tz = sys_tz;
	73	write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags);
	74	}
	75
7460ed28	76	void update_vsyscall(struct timespec wall_time, struct clocksource clock)
1da177e4	77	{
7460ed28	78	unsigned long flags;
1da177e4	79
7460ed28	80	write_seqlock_irqsave(&vsyscall_gtod_data.lock, flags);
7460ed28	81	/* copy vsyscall data */
c8118c6c ED	82	vsyscall_gtod_data.clock.vread = clock->vread;
	83	vsyscall_gtod_data.clock.cycle_last = clock->cycle_last;
	84	vsyscall_gtod_data.clock.mask = clock->mask;
	85	vsyscall_gtod_data.clock.mult = clock->mult;
	86	vsyscall_gtod_data.clock.shift = clock->shift;
	87	vsyscall_gtod_data.wall_time_sec = wall_time->tv_sec;
	88	vsyscall_gtod_data.wall_time_nsec = wall_time->tv_nsec;
2aae950b	89	vsyscall_gtod_data.wall_to_monotonic = wall_to_monotonic;
7460ed28	90	write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags);
1da177e4 LT	91	}
1da177e4 LT	92
7460ed28	93	/* RED-PEN may want to readd seq locking, but then the variable should be
	94	* write-once.
	95	*/
2c8bc944	96	static __always_inline void do_get_tz(struct timezone * tz)
1da177e4	97	{
7460ed28	98	*tz = __vsyscall_gtod_data.sys_tz;
1da177e4 LT	99	}
1da177e4 LT	100
2c8bc944	101	static __always_inline int gettimeofday(struct timeval tv, struct timezone tz)
1da177e4 LT	102	{
1da177e4 LT	103	int ret;
ce28b986	104	asm volatile("syscall"
1da177e4	105	: "=a" (ret)
7460ed28	106	: "0" (__NR_gettimeofday),"D" (tv),"S" (tz)
7460ed28	107	: __syscall_clobber );
1da177e4 LT	108	return ret;
	109	}
	110
2c8bc944	111	static __always_inline long time_syscall(long *t)
1da177e4 LT	112	{
1da177e4 LT	113	long secs;
ce28b986	114	asm volatile("syscall"
1da177e4 LT	115	: "=a" (secs)
	116	: "0" (__NR_time),"D" (t) : __syscall_clobber);
	117	return secs;
	118	}
	119
7460ed28	120	static __always_inline void do_vgettimeofday(struct timeval * tv)
	121	{
	122	cycle_t now, base, mask, cycle_delta;
c8118c6c ED	123	unsigned seq;
c8118c6c ED	124	unsigned long mult, shift, nsec;
7460ed28	125	cycle_t (*vread)(void);
	126	do {
	127	seq = read_seqbegin(&__vsyscall_gtod_data.lock);
	128
	129	vread = __vsyscall_gtod_data.clock.vread;
	130	if (unlikely(!__vsyscall_gtod_data.sysctl_enabled \|\| !vread)) {
89952d13	131	gettimeofday(tv,NULL);
7460ed28	132	return;
7460ed28	133	}
cb9e35dc	134
7460ed28	135	now = vread();
	136	base = __vsyscall_gtod_data.clock.cycle_last;
	137	mask = __vsyscall_gtod_data.clock.mask;
	138	mult = __vsyscall_gtod_data.clock.mult;
	139	shift = __vsyscall_gtod_data.clock.shift;
	140
c8118c6c ED	141	tv->tv_sec = __vsyscall_gtod_data.wall_time_sec;
c8118c6c ED	142	nsec = __vsyscall_gtod_data.wall_time_nsec;
7460ed28	143	} while (read_seqretry(&__vsyscall_gtod_data.lock, seq));
	144
	145	/* calculate interval: */
	146	cycle_delta = (now - base) & mask;
	147	/* convert to nsecs: */
c8118c6c	148	nsec += (cycle_delta * mult) >> shift;
7460ed28	149
c8118c6c	150	while (nsec >= NSEC_PER_SEC) {
7460ed28	151	tv->tv_sec += 1;
c8118c6c	152	nsec -= NSEC_PER_SEC;
7460ed28	153	}
c8118c6c	154	tv->tv_usec = nsec / NSEC_PER_USEC;
7460ed28	155	}
7460ed28	156
2e8ad43e	157	int __vsyscall(0) vgettimeofday(struct timeval * tv, struct timezone * tz)
1da177e4	158	{
1da177e4 LT	159	if (tv)
	160	do_vgettimeofday(tv);
	161	if (tz)
	162	do_get_tz(tz);
	163	return 0;
	164	}
	165
	166	/* This will break when the xtime seconds get inaccurate, but that is
	167	* unlikely */
2e8ad43e	168	time_t __vsyscall(1) vtime(time_t *t)
1da177e4	169	{
d0aff6e6	170	struct timeval tv;
272a3713	171	time_t result;
7460ed28	172	if (unlikely(!__vsyscall_gtod_data.sysctl_enabled))
1da177e4	173	return time_syscall(t);
d0aff6e6	174
c80544dc	175	vgettimeofday(&tv, NULL);
d0aff6e6	176	result = tv.tv_sec;
272a3713 ED	177	if (t)
	178	*t = result;
	179	return result;
1da177e4 LT	180	}
1da177e4 LT	181
c08c8205 VP	182	/* Fast way to get current CPU and node.
	183	This helps to do per node and per CPU caches in user space.
	184	The result is not guaranteed without CPU affinity, but usually
	185	works out because the scheduler tries to keep a thread on the same
	186	CPU.
	187
	188	tcache must point to a two element sized long array.
	189	All arguments can be NULL. */
	190	long __vsyscall(2)
	191	vgetcpu(unsigned cpu, unsigned node, struct getcpu_cache *tcache)
1da177e4	192	{
8f12dea6	193	unsigned int p;
c08c8205 VP	194	unsigned long j = 0;
	195
	196	/* Fast cache - only recompute value once per jiffies and avoid
	197	relatively costly rdtscp/cpuid otherwise.
	198	This works because the scheduler usually keeps the process
	199	on the same CPU and this syscall doesn't guarantee its
	200	results anyways.
	201	We do this here because otherwise user space would do it on
	202	its own in a likely inferior way (no access to jiffies).
	203	If you don't like it pass NULL. */
34596dc9 AK	204	if (tcache && tcache->blob[0] == (j = __jiffies)) {
34596dc9 AK	205	p = tcache->blob[1];
c08c8205 VP	206	} else if (__vgetcpu_mode == VGETCPU_RDTSCP) {
c08c8205 VP	207	/* Load per CPU data from RDTSCP */
8f12dea6	208	native_read_tscp(&p);
c08c8205 VP	209	} else {
	210	/* Load per CPU data from GDT */
	211	asm("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG));
	212	}
	213	if (tcache) {
34596dc9 AK	214	tcache->blob[0] = j;
34596dc9 AK	215	tcache->blob[1] = p;
c08c8205 VP	216	}
	217	if (cpu)
	218	*cpu = p & 0xfff;
	219	if (node)
	220	*node = p >> 12;
	221	return 0;
1da177e4 LT	222	}
1da177e4 LT	223
a4928cff	224	static long __vsyscall(3) venosys_1(void)
1da177e4 LT	225	{
	226	return -ENOSYS;
	227	}
	228
	229	#ifdef CONFIG_SYSCTL
d67bbacb TG	230
	231	static int
	232	vsyscall_sysctl_change(ctl_table ctl, int write, struct file filp,
	233	void __user buffer, size_t lenp, loff_t *ppos)
	234	{
	235	return proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
	236	}
	237
1da177e4	238	static ctl_table kernel_table2[] = {
282a821f	239	{ .procname = "vsyscall64",
7460ed28	240	.data = &vsyscall_gtod_data.sysctl_enabled, .maxlen = sizeof(int),
d67bbacb TG	241	.mode = 0644,
d67bbacb TG	242	.proc_handler = vsyscall_sysctl_change },
7a44d37d	243	{}
1da177e4 LT	244	};
	245
	246	static ctl_table kernel_root_table2[] = {
	247	{ .ctl_name = CTL_KERN, .procname = "kernel", .mode = 0555,
	248	.child = kernel_table2 },
7a44d37d	249	{}
1da177e4	250	};
1da177e4 LT	251	#endif
1da177e4 LT	252
8c131af1 AK	253	/* Assume __initcall executes before all user space. Hopefully kmod
	254	doesn't violate that. We'll find out if it does. */
	255	static void __cpuinit vsyscall_set_cpu(int cpu)
c08c8205	256	{
fc8b8a60	257	unsigned long d;
c08c8205 VP	258	unsigned long node = 0;
c08c8205 VP	259	#ifdef CONFIG_NUMA
98c9e27a	260	node = cpu_to_node(cpu);
c08c8205	261	#endif
92cb7612	262	if (cpu_has(&cpu_data(cpu), X86_FEATURE_RDTSCP))
8c131af1	263	write_rdtscp_aux((node << 12) \| cpu);
c08c8205 VP	264
	265	/* Store cpu number in limit so that it can be loaded quickly
	266	in user space in vgetcpu.
	267	12 bits for the CPU and 8 bits for the node. */
fc8b8a60 JF	268	d = 0x0f40000000000ULL;
	269	d \|= cpu;
	270	d \|= (node & 0xf) << 12;
	271	d \|= (node >> 4) << 48;
	272	write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_PER_CPU, &d, DESCTYPE_S);
c08c8205 VP	273	}
c08c8205 VP	274
8c131af1 AK	275	static void __cpuinit cpu_vsyscall_init(void *arg)
	276	{
	277	/* preemption should be already off */
	278	vsyscall_set_cpu(raw_smp_processor_id());
	279	}
	280
	281	static int __cpuinit
	282	cpu_vsyscall_notifier(struct notifier_block n, unsigned long action, void arg)
	283	{
	284	long cpu = (long)arg;
8bb78442	285	if (action == CPU_ONLINE \|\| action == CPU_ONLINE_FROZEN)
8691e5a8	286	smp_call_function_single(cpu, cpu_vsyscall_init, NULL, 1);
8c131af1 AK	287	return NOTIFY_DONE;
	288	}
	289
e4026440	290	void __init map_vsyscall(void)
1da177e4 LT	291	{
	292	extern char __vsyscall_0;
	293	unsigned long physaddr_page0 = __pa_symbol(&__vsyscall_0);
	294
103efcd9	295	/* Note that VSYSCALL_MAPPED_PAGES must agree with the code below. */
1da177e4 LT	296	__set_fixmap(VSYSCALL_FIRST_PAGE, physaddr_page0, PAGE_KERNEL_VSYSCALL);
	297	}
	298
	299	static int __init vsyscall_init(void)
	300	{
	301	BUG_ON(((unsigned long) &vgettimeofday !=
	302	VSYSCALL_ADDR(__NR_vgettimeofday)));
	303	BUG_ON((unsigned long) &vtime != VSYSCALL_ADDR(__NR_vtime));
	304	BUG_ON((VSYSCALL_ADDR(0) != __fix_to_virt(VSYSCALL_FIRST_PAGE)));
c08c8205	305	BUG_ON((unsigned long) &vgetcpu != VSYSCALL_ADDR(__NR_vgetcpu));
f3c5f5e7	306	#ifdef CONFIG_SYSCTL
0b4d4147	307	register_sysctl_table(kernel_root_table2);
f3c5f5e7	308	#endif
15c8b6c1	309	on_each_cpu(cpu_vsyscall_init, NULL, 1);
8c131af1	310	hotcpu_notifier(cpu_vsyscall_notifier, 0);
1da177e4 LT	311	return 0;
	312	}
	313
	314	__initcall(vsyscall_init);