x86_64: move kernel
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Thomas Gleixner
349
arch/x86/kernel/vsyscall_64.c
Normal file
349
arch/x86/kernel/vsyscall_64.c
Normal file
@@ -0,0 +1,349 @@
|
||||
/*
|
||||
* linux/arch/x86_64/kernel/vsyscall.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.
|
||||
*/
|
||||
|
||||
#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)))
|
||||
#define __syscall_clobber "r11","rcx","memory"
|
||||
#define __pa_vsymbol(x) \
|
||||
({unsigned long v; \
|
||||
extern char __vsyscall_0; \
|
||||
asm("" : "=r" (v) : "0" (x)); \
|
||||
((v - VSYSCALL_FIRST_PAGE) + __pa_symbol(&__vsyscall_0)); })
|
||||
|
||||
/*
|
||||
* vsyscall_gtod_data contains data that is :
|
||||
* - readonly from vsyscalls
|
||||
* - writen 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(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.sys_tz = sys_tz;
|
||||
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("vsysc2: 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("vsysc1: 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, 0);
|
||||
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 dummy, 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 */
|
||||
rdtscp(dummy, dummy, 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;
|
||||
}
|
||||
|
||||
long __vsyscall(3) venosys_1(void)
|
||||
{
|
||||
return -ENOSYS;
|
||||
}
|
||||
|
||||
#ifdef CONFIG_SYSCTL
|
||||
|
||||
#define SYSCALL 0x050f
|
||||
#define NOP2 0x9090
|
||||
|
||||
/*
|
||||
* NOP out syscall in vsyscall page when not needed.
|
||||
*/
|
||||
static int vsyscall_sysctl_change(ctl_table *ctl, int write, struct file * filp,
|
||||
void __user *buffer, size_t *lenp, loff_t *ppos)
|
||||
{
|
||||
extern u16 vsysc1, vsysc2;
|
||||
u16 __iomem *map1;
|
||||
u16 __iomem *map2;
|
||||
int ret = proc_dointvec(ctl, write, filp, buffer, lenp, ppos);
|
||||
if (!write)
|
||||
return ret;
|
||||
/* gcc has some trouble with __va(__pa()), so just do it this
|
||||
way. */
|
||||
map1 = ioremap(__pa_vsymbol(&vsysc1), 2);
|
||||
if (!map1)
|
||||
return -ENOMEM;
|
||||
map2 = ioremap(__pa_vsymbol(&vsysc2), 2);
|
||||
if (!map2) {
|
||||
ret = -ENOMEM;
|
||||
goto out;
|
||||
}
|
||||
if (!vsyscall_gtod_data.sysctl_enabled) {
|
||||
writew(SYSCALL, map1);
|
||||
writew(SYSCALL, map2);
|
||||
} else {
|
||||
writew(NOP2, map1);
|
||||
writew(NOP2, map2);
|
||||
}
|
||||
iounmap(map2);
|
||||
out:
|
||||
iounmap(map1);
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int vsyscall_sysctl_nostrat(ctl_table *t, int __user *name, int nlen,
|
||||
void __user *oldval, size_t __user *oldlenp,
|
||||
void __user *newval, size_t newlen)
|
||||
{
|
||||
return -ENOSYS;
|
||||
}
|
||||
|
||||
static ctl_table kernel_table2[] = {
|
||||
{ .ctl_name = 99, .procname = "vsyscall64",
|
||||
.data = &vsyscall_gtod_data.sysctl_enabled, .maxlen = sizeof(int),
|
||||
.mode = 0644,
|
||||
.strategy = vsyscall_sysctl_nostrat,
|
||||
.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 = (unsigned long *)(cpu_gdt(cpu) + GDT_ENTRY_PER_CPU);
|
||||
*d = 0x0f40000000000ULL;
|
||||
*d |= cpu;
|
||||
*d |= (node & 0xf) << 12;
|
||||
*d |= (node >> 4) << 48;
|
||||
}
|
||||
|
||||
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, 0, 1);
|
||||
return NOTIFY_DONE;
|
||||
}
|
||||
|
||||
static 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));
|
||||
map_vsyscall();
|
||||
#ifdef CONFIG_SYSCTL
|
||||
register_sysctl_table(kernel_root_table2);
|
||||
#endif
|
||||
on_each_cpu(cpu_vsyscall_init, NULL, 0, 1);
|
||||
hotcpu_notifier(cpu_vsyscall_notifier, 0);
|
||||
return 0;
|
||||
}
|
||||
|
||||
__initcall(vsyscall_init);
|
||||
Reference in New Issue
Block a user