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

/*
 *  Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
 *  Copyright 2003 Andi Kleen, SuSE Labs.
 *
 *  [ NOTE: this mechanism is now deprecated in favor of the vDSO. ]
 *
 *  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.
 *
 *  Note: the concept clashes with user mode linux.  UML users should
 *  use the vDSO.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#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/topology.h>
#include <linux/timekeeper_internal.h>
#include <linux/getcpu.h>
#include <linux/cpu.h>
#include <linux/smp.h>
#include <linux/notifier.h>
#include <linux/syscalls.h>
#include <linux/ratelimit.h>

#include <asm/vsyscall.h>
#include <asm/pgtable.h>
#include <asm/compat.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/traps.h>

#define CREATE_TRACE_POINTS
#include "vsyscall_trace.h"

DEFINE_VVAR(int, vgetcpu_mode);

static enum { EMULATE, NATIVE, NONE } vsyscall_mode = EMULATE;

static int __init vsyscall_setup(char *str)
{
	if (str) {
		if (!strcmp("emulate", str))
			vsyscall_mode = EMULATE;
		else if (!strcmp("native", str))
			vsyscall_mode = NATIVE;
		else if (!strcmp("none", str))
			vsyscall_mode = NONE;
		else
			return -EINVAL;

		return 0;
	}

	return -EINVAL;
}
early_param("vsyscall", vsyscall_setup);

static void warn_bad_vsyscall(const char *level, struct pt_regs *regs,
			      const char *message)
{
	if (!show_unhandled_signals)
		return;

	pr_notice_ratelimited("%s%s[%d] %s ip:%lx cs:%lx sp:%lx ax:%lx si:%lx di:%lx\n",
			      level, current->comm, task_pid_nr(current),
			      message, regs->ip, regs->cs,
			      regs->sp, regs->ax, regs->si, regs->di);
}

static int addr_to_vsyscall_nr(unsigned long addr)
{
	int nr;

	if ((addr & ~0xC00UL) != VSYSCALL_ADDR)
		return -EINVAL;

	nr = (addr & 0xC00UL) >> 10;
	if (nr >= 3)
		return -EINVAL;

	return nr;
}

static bool write_ok_or_segv(unsigned long ptr, size_t size)
{
	/*
	 * XXX: if access_ok, get_user, and put_user handled
	 * sig_on_uaccess_error, this could go away.
	 */

	if (!access_ok(VERIFY_WRITE, (void __user *)ptr, size)) {
		siginfo_t info;
		struct thread_struct *thread = &current->thread;

		thread->error_code	= 6;  /* user fault, no page, write */
		thread->cr2		= ptr;
		thread->trap_nr		= X86_TRAP_PF;

		memset(&info, 0, sizeof(info));
		info.si_signo		= SIGSEGV;
		info.si_errno		= 0;
		info.si_code		= SEGV_MAPERR;
		info.si_addr		= (void __user *)ptr;

		force_sig_info(SIGSEGV, &info, current);
		return false;
	} else {
		return true;
	}
}

bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
{
	struct task_struct *tsk;
	unsigned long caller;
	int vsyscall_nr, syscall_nr, tmp;
	int prev_sig_on_uaccess_error;
	long ret;

	/*
	 * No point in checking CS -- the only way to get here is a user mode
	 * trap to a high address, which means that we're in 64-bit user code.
	 */

	WARN_ON_ONCE(address != regs->ip);

	if (vsyscall_mode == NONE) {
		warn_bad_vsyscall(KERN_INFO, regs,
				  "vsyscall attempted with vsyscall=none");
		return false;
	}

	vsyscall_nr = addr_to_vsyscall_nr(address);

	trace_emulate_vsyscall(vsyscall_nr);

	if (vsyscall_nr < 0) {
		warn_bad_vsyscall(KERN_WARNING, regs,
				  "misaligned vsyscall (exploit attempt or buggy program) -- look up the vsyscall kernel parameter if you need a workaround");
		goto sigsegv;
	}

	if (get_user(caller, (unsigned long __user *)regs->sp) != 0) {
		warn_bad_vsyscall(KERN_WARNING, regs,
				  "vsyscall with bad stack (exploit attempt?)");
		goto sigsegv;
	}

	tsk = current;

	/*
	 * Check for access_ok violations and find the syscall nr.
	 *
	 * NULL is a valid user pointer (in the access_ok sense) on 32-bit and
	 * 64-bit, so we don't need to special-case it here.  For all the
	 * vsyscalls, NULL means "don't write anything" not "write it at
	 * address 0".
	 */
	switch (vsyscall_nr) {
	case 0:
		if (!write_ok_or_segv(regs->di, sizeof(struct timeval)) ||
		    !write_ok_or_segv(regs->si, sizeof(struct timezone))) {
			ret = -EFAULT;
			goto check_fault;
		}

		syscall_nr = __NR_gettimeofday;
		break;

	case 1:
		if (!write_ok_or_segv(regs->di, sizeof(time_t))) {
			ret = -EFAULT;
			goto check_fault;
		}

		syscall_nr = __NR_time;
		break;

	case 2:
		if (!write_ok_or_segv(regs->di, sizeof(unsigned)) ||
		    !write_ok_or_segv(regs->si, sizeof(unsigned))) {
			ret = -EFAULT;
			goto check_fault;
		}

		syscall_nr = __NR_getcpu;
		break;
	}

	/*
	 * Handle seccomp.  regs->ip must be the original value.
	 * See seccomp_send_sigsys and Documentation/prctl/seccomp_filter.txt.
	 *
	 * We could optimize the seccomp disabled case, but performance
	 * here doesn't matter.
	 */
	regs->orig_ax = syscall_nr;
	regs->ax = -ENOSYS;
	tmp = secure_computing(syscall_nr);
	if ((!tmp && regs->orig_ax != syscall_nr) || regs->ip != address) {
		warn_bad_vsyscall(KERN_DEBUG, regs,
				  "seccomp tried to change syscall nr or ip");
		do_exit(SIGSYS);
	}
	if (tmp)
		goto do_ret;  /* skip requested */

	/*
	 * With a real vsyscall, page faults cause SIGSEGV.  We want to
	 * preserve that behavior to make writing exploits harder.
	 */
	prev_sig_on_uaccess_error = current_thread_info()->sig_on_uaccess_error;
	current_thread_info()->sig_on_uaccess_error = 1;

	ret = -EFAULT;
	switch (vsyscall_nr) {
	case 0:
		ret = sys_gettimeofday(
			(struct timeval __user *)regs->di,
			(struct timezone __user *)regs->si);
		break;

	case 1:
		ret = sys_time((time_t __user *)regs->di);
		break;

	case 2:
		ret = sys_getcpu((unsigned __user *)regs->di,
				 (unsigned __user *)regs->si,
				 NULL);
		break;
	}

	current_thread_info()->sig_on_uaccess_error = prev_sig_on_uaccess_error;

check_fault:
	if (ret == -EFAULT) {
		/* Bad news -- userspace fed a bad pointer to a vsyscall. */
		warn_bad_vsyscall(KERN_INFO, regs,
				  "vsyscall fault (exploit attempt?)");

		/*
		 * If we failed to generate a signal for any reason,
		 * generate one here.  (This should be impossible.)
		 */
		if (WARN_ON_ONCE(!sigismember(&tsk->pending.signal, SIGBUS) &&
				 !sigismember(&tsk->pending.signal, SIGSEGV)))
			goto sigsegv;

		return true;  /* Don't emulate the ret. */
	}

	regs->ax = ret;

do_ret:
	/* Emulate a ret instruction. */
	regs->ip = caller;
	regs->sp += 8;
	return true;

sigsegv:
	force_sig(SIGSEGV, current);
	return true;
}

/*
 * Assume __initcall executes before all user space. Hopefully kmod
 * doesn't violate that. We'll find out if it does.
 */
static void 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 cpu_vsyscall_init(void *arg)
{
	/* preemption should be already off */
	vsyscall_set_cpu(raw_smp_processor_id());
}

static int
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_page;
	unsigned long physaddr_vsyscall = __pa_symbol(&__vsyscall_page);

	__set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall,
		     vsyscall_mode == NATIVE
		     ? PAGE_KERNEL_VSYSCALL
		     : PAGE_KERNEL_VVAR);
	BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) !=
		     (unsigned long)VSYSCALL_ADDR);
}

static int __init vsyscall_init(void)
{
	cpu_notifier_register_begin();

	on_each_cpu(cpu_vsyscall_init, NULL, 1);
	/* notifier priority > KVM */
	__hotcpu_notifier(cpu_vsyscall_notifier, 30);

	cpu_notifier_register_done();

	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	*
5cec93c2 AL	5	* [ NOTE: this mechanism is now deprecated in favor of the vDSO. ]
5cec93c2 AL	6	*
1da177e4 LT	7	* Thanks to hpa@transmeta.com for some useful hint.
	8	* Special thanks to Ingo Molnar for his early experience with
	9	* a different vsyscall implementation for Linux/IA32 and for the name.
	10	*
	11	* vsyscall 1 is located at -10Mbyte, vsyscall 2 is located
	12	* at virtual address -10Mbyte+1024bytes etc... There are at max 4
	13	* vsyscalls. One vsyscall can reserve more than 1 slot to avoid
	14	* jumping out of line if necessary. We cannot add more with this
	15	* mechanism because older kernels won't return -ENOSYS.
1da177e4	16	*
5cec93c2 AL	17	* Note: the concept clashes with user mode linux. UML users should
5cec93c2 AL	18	* use the vDSO.
1da177e4 LT	19	*/
1da177e4 LT	20
c767a54b JP	21	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
c767a54b JP	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>
29574022	30	#include <linux/topology.h>
189374ae	31	#include <linux/timekeeper_internal.h>
c08c8205	32	#include <linux/getcpu.h>
8c131af1 AK	33	#include <linux/cpu.h>
	34	#include <linux/smp.h>
	35	#include <linux/notifier.h>
5cec93c2 AL	36	#include <linux/syscalls.h>
5cec93c2 AL	37	#include <linux/ratelimit.h>
1da177e4 LT	38
	39	#include <asm/vsyscall.h>
	40	#include <asm/pgtable.h>
c9712944	41	#include <asm/compat.h>
1da177e4	42	#include <asm/page.h>
7460ed28	43	#include <asm/unistd.h>
1da177e4 LT	44	#include <asm/fixmap.h>
	45	#include <asm/errno.h>
	46	#include <asm/io.h>
c08c8205 VP	47	#include <asm/segment.h>
	48	#include <asm/desc.h>
	49	#include <asm/topology.h>
5cec93c2	50	#include <asm/traps.h>
1da177e4	51
c149a665 AL	52	#define CREATE_TRACE_POINTS
	53	#include "vsyscall_trace.h"
	54
8c49d9a7	55	DEFINE_VVAR(int, vgetcpu_mode);
1da177e4	56
2e57ae05	57	static enum { EMULATE, NATIVE, NONE } vsyscall_mode = EMULATE;
3ae36655 AL	58
	59	static int __init vsyscall_setup(char *str)
	60	{
	61	if (str) {
	62	if (!strcmp("emulate", str))
	63	vsyscall_mode = EMULATE;
	64	else if (!strcmp("native", str))
	65	vsyscall_mode = NATIVE;
	66	else if (!strcmp("none", str))
	67	vsyscall_mode = NONE;
	68	else
	69	return -EINVAL;
	70
	71	return 0;
	72	}
	73
	74	return -EINVAL;
	75	}
	76	early_param("vsyscall", vsyscall_setup);
	77
5cec93c2 AL	78	static void warn_bad_vsyscall(const char level, struct pt_regs regs,
5cec93c2 AL	79	const char *message)
1da177e4	80	{
c767a54b	81	if (!show_unhandled_signals)
5cec93c2	82	return;
1da177e4	83
c767a54b JP	84	pr_notice_ratelimited("%s%s[%d] %s ip:%lx cs:%lx sp:%lx ax:%lx si:%lx di:%lx\n",
	85	level, current->comm, task_pid_nr(current),
	86	message, regs->ip, regs->cs,
	87	regs->sp, regs->ax, regs->si, regs->di);
c9712944 AL	88	}
	89
	90	static int addr_to_vsyscall_nr(unsigned long addr)
	91	{
	92	int nr;
	93
f40c3300	94	if ((addr & ~0xC00UL) != VSYSCALL_ADDR)
c9712944 AL	95	return -EINVAL;
	96
	97	nr = (addr & 0xC00UL) >> 10;
	98	if (nr >= 3)
	99	return -EINVAL;
	100
	101	return nr;
1da177e4 LT	102	}
1da177e4 LT	103
4fc34901 AL	104	static bool write_ok_or_segv(unsigned long ptr, size_t size)
	105	{
	106	/*
	107	* XXX: if access_ok, get_user, and put_user handled
	108	* sig_on_uaccess_error, this could go away.
	109	*/
	110
	111	if (!access_ok(VERIFY_WRITE, (void __user *)ptr, size)) {
	112	siginfo_t info;
	113	struct thread_struct *thread = &current->thread;
	114
	115	thread->error_code = 6; /* user fault, no page, write */
	116	thread->cr2 = ptr;
51e7dc70	117	thread->trap_nr = X86_TRAP_PF;
4fc34901 AL	118
	119	memset(&info, 0, sizeof(info));
	120	info.si_signo = SIGSEGV;
	121	info.si_errno = 0;
	122	info.si_code = SEGV_MAPERR;
	123	info.si_addr = (void __user *)ptr;
	124
	125	force_sig_info(SIGSEGV, &info, current);
	126	return false;
	127	} else {
	128	return true;
	129	}
	130	}
	131
3ae36655	132	bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
1da177e4	133	{
5cec93c2 AL	134	struct task_struct *tsk;
5cec93c2 AL	135	unsigned long caller;
87b526d3	136	int vsyscall_nr, syscall_nr, tmp;
4fc34901	137	int prev_sig_on_uaccess_error;
5cec93c2 AL	138	long ret;
5cec93c2 AL	139
3ae36655 AL	140	/*
	141	* No point in checking CS -- the only way to get here is a user mode
	142	* trap to a high address, which means that we're in 64-bit user code.
	143	*/
5cec93c2	144
3ae36655	145	WARN_ON_ONCE(address != regs->ip);
c9712944	146
3ae36655 AL	147	if (vsyscall_mode == NONE) {
	148	warn_bad_vsyscall(KERN_INFO, regs,
	149	"vsyscall attempted with vsyscall=none");
	150	return false;
c9712944 AL	151	}
c9712944 AL	152
3ae36655	153	vsyscall_nr = addr_to_vsyscall_nr(address);
c149a665 AL	154
	155	trace_emulate_vsyscall(vsyscall_nr);
	156
c9712944 AL	157	if (vsyscall_nr < 0) {
c9712944 AL	158	warn_bad_vsyscall(KERN_WARNING, regs,
3ae36655	159	"misaligned vsyscall (exploit attempt or buggy program) -- look up the vsyscall kernel parameter if you need a workaround");
5cec93c2 AL	160	goto sigsegv;
5cec93c2 AL	161	}
d0aff6e6	162
5cec93c2	163	if (get_user(caller, (unsigned long __user *)regs->sp) != 0) {
3ae36655 AL	164	warn_bad_vsyscall(KERN_WARNING, regs,
3ae36655 AL	165	"vsyscall with bad stack (exploit attempt?)");
5cec93c2 AL	166	goto sigsegv;
5cec93c2 AL	167	}
8c73626a	168
5cec93c2	169	tsk = current;
4fc34901 AL	170
4fc34901 AL	171	/*
87b526d3 AL	172	* Check for access_ok violations and find the syscall nr.
87b526d3 AL	173	*
46ed99d1	174	* NULL is a valid user pointer (in the access_ok sense) on 32-bit and
4fc34901	175	* 64-bit, so we don't need to special-case it here. For all the
46ed99d1	176	* vsyscalls, NULL means "don't write anything" not "write it at
4fc34901 AL	177	* address 0".
4fc34901 AL	178	*/
5cec93c2 AL	179	switch (vsyscall_nr) {
5cec93c2 AL	180	case 0:
4fc34901	181	if (!write_ok_or_segv(regs->di, sizeof(struct timeval)) \|\|
87b526d3 AL	182	!write_ok_or_segv(regs->si, sizeof(struct timezone))) {
	183	ret = -EFAULT;
	184	goto check_fault;
	185	}
4fc34901	186
87b526d3 AL	187	syscall_nr = __NR_gettimeofday;
	188	break;
	189
	190	case 1:
	191	if (!write_ok_or_segv(regs->di, sizeof(time_t))) {
	192	ret = -EFAULT;
	193	goto check_fault;
	194	}
	195
	196	syscall_nr = __NR_time;
	197	break;
	198
	199	case 2:
	200	if (!write_ok_or_segv(regs->di, sizeof(unsigned)) \|\|
	201	!write_ok_or_segv(regs->si, sizeof(unsigned))) {
	202	ret = -EFAULT;
	203	goto check_fault;
	204	}
	205
	206	syscall_nr = __NR_getcpu;
	207	break;
	208	}
	209
	210	/*
	211	* Handle seccomp. regs->ip must be the original value.
	212	* See seccomp_send_sigsys and Documentation/prctl/seccomp_filter.txt.
	213	*
	214	* We could optimize the seccomp disabled case, but performance
	215	* here doesn't matter.
	216	*/
	217	regs->orig_ax = syscall_nr;
	218	regs->ax = -ENOSYS;
	219	tmp = secure_computing(syscall_nr);
	220	if ((!tmp && regs->orig_ax != syscall_nr) \|\| regs->ip != address) {
	221	warn_bad_vsyscall(KERN_DEBUG, regs,
	222	"seccomp tried to change syscall nr or ip");
	223	do_exit(SIGSYS);
	224	}
	225	if (tmp)
	226	goto do_ret; /* skip requested */
	227
	228	/*
	229	* With a real vsyscall, page faults cause SIGSEGV. We want to
	230	* preserve that behavior to make writing exploits harder.
	231	*/
	232	prev_sig_on_uaccess_error = current_thread_info()->sig_on_uaccess_error;
	233	current_thread_info()->sig_on_uaccess_error = 1;
	234
	235	ret = -EFAULT;
	236	switch (vsyscall_nr) {
	237	case 0:
5cec93c2 AL	238	ret = sys_gettimeofday(
	239	(struct timeval __user *)regs->di,
	240	(struct timezone __user *)regs->si);
	241	break;
	242
	243	case 1:
5cec93c2 AL	244	ret = sys_time((time_t __user *)regs->di);
	245	break;
	246
	247	case 2:
5cec93c2 AL	248	ret = sys_getcpu((unsigned __user *)regs->di,
5cec93c2 AL	249	(unsigned __user *)regs->si,
46ed99d1	250	NULL);
5cec93c2	251	break;
5cec93c2	252	}
8c73626a	253
4fc34901 AL	254	current_thread_info()->sig_on_uaccess_error = prev_sig_on_uaccess_error;
4fc34901 AL	255
87b526d3	256	check_fault:
5cec93c2	257	if (ret == -EFAULT) {
4fc34901	258	/* Bad news -- userspace fed a bad pointer to a vsyscall. */
5cec93c2 AL	259	warn_bad_vsyscall(KERN_INFO, regs,
5cec93c2 AL	260	"vsyscall fault (exploit attempt?)");
4fc34901 AL	261
	262	/*
	263	* If we failed to generate a signal for any reason,
	264	* generate one here. (This should be impossible.)
	265	*/
	266	if (WARN_ON_ONCE(!sigismember(&tsk->pending.signal, SIGBUS) &&
	267	!sigismember(&tsk->pending.signal, SIGSEGV)))
	268	goto sigsegv;
	269
	270	return true; /* Don't emulate the ret. */
5cec93c2	271	}
8c73626a	272
5cec93c2	273	regs->ax = ret;
1da177e4	274
5651721e	275	do_ret:
5cec93c2 AL	276	/* Emulate a ret instruction. */
	277	regs->ip = caller;
	278	regs->sp += 8;
3ae36655	279	return true;
5cec93c2 AL	280
5cec93c2 AL	281	sigsegv:
5cec93c2	282	force_sig(SIGSEGV, current);
3ae36655	283	return true;
1da177e4 LT	284	}
1da177e4 LT	285
5cec93c2 AL	286	/*
	287	* Assume __initcall executes before all user space. Hopefully kmod
	288	* doesn't violate that. We'll find out if it does.
	289	*/
148f9bb8	290	static void vsyscall_set_cpu(int cpu)
c08c8205	291	{
fc8b8a60	292	unsigned long d;
c08c8205 VP	293	unsigned long node = 0;
c08c8205 VP	294	#ifdef CONFIG_NUMA
98c9e27a	295	node = cpu_to_node(cpu);
c08c8205	296	#endif
92cb7612	297	if (cpu_has(&cpu_data(cpu), X86_FEATURE_RDTSCP))
8c131af1	298	write_rdtscp_aux((node << 12) \| cpu);
c08c8205	299
5cec93c2 AL	300	/*
	301	* Store cpu number in limit so that it can be loaded quickly
	302	* in user space in vgetcpu. (12 bits for the CPU and 8 bits for the node)
	303	*/
fc8b8a60 JF	304	d = 0x0f40000000000ULL;
	305	d \|= cpu;
	306	d \|= (node & 0xf) << 12;
	307	d \|= (node >> 4) << 48;
5cec93c2	308
fc8b8a60	309	write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_PER_CPU, &d, DESCTYPE_S);
c08c8205 VP	310	}
c08c8205 VP	311
148f9bb8	312	static void cpu_vsyscall_init(void *arg)
8c131af1 AK	313	{
	314	/* preemption should be already off */
	315	vsyscall_set_cpu(raw_smp_processor_id());
	316	}
	317
148f9bb8	318	static int
8c131af1 AK	319	cpu_vsyscall_notifier(struct notifier_block n, unsigned long action, void arg)
	320	{
	321	long cpu = (long)arg;
5cec93c2	322
8bb78442	323	if (action == CPU_ONLINE \|\| action == CPU_ONLINE_FROZEN)
8691e5a8	324	smp_call_function_single(cpu, cpu_vsyscall_init, NULL, 1);
5cec93c2	325
8c131af1 AK	326	return NOTIFY_DONE;
	327	}
	328
e4026440	329	void __init map_vsyscall(void)
1da177e4	330	{
3ae36655 AL	331	extern char __vsyscall_page;
3ae36655 AL	332	unsigned long physaddr_vsyscall = __pa_symbol(&__vsyscall_page);
1da177e4	333
f40c3300	334	__set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall,
3ae36655 AL	335	vsyscall_mode == NATIVE
	336	? PAGE_KERNEL_VSYSCALL
	337	: PAGE_KERNEL_VVAR);
f40c3300 AL	338	BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) !=
f40c3300 AL	339	(unsigned long)VSYSCALL_ADDR);
1da177e4 LT	340	}
	341
	342	static int __init vsyscall_init(void)
	343	{
42112a0f SB	344	cpu_notifier_register_begin();
42112a0f SB	345
15c8b6c1	346	on_each_cpu(cpu_vsyscall_init, NULL, 1);
be43f83d	347	/* notifier priority > KVM */
42112a0f SB	348	__hotcpu_notifier(cpu_vsyscall_notifier, 30);
	349
	350	cpu_notifier_register_done();
5cec93c2	351
1da177e4 LT	352	return 0;
1da177e4 LT	353	}
1da177e4	354	__initcall(vsyscall_init);