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[PATCH] time: x86_64: re-enable vsyscall support for x86_64

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Cleanup and re-enable vsyscall gettimeofday using the generic clocksource
infrastructure.

[akpm@osdl.org: cleanup]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@muc.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
john stultz 2007-02-16 01:28:21 -08:00 committed by Linus Torvalds
parent 1489939f0a
commit 7460ed2844
9 changed files with 106 additions and 100 deletions
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4
arch/x86_64/Kconfig
View file

@ -28,6 +28,10 @@ config GENERIC_TIME
bool
default y
config GENERIC_TIME_VSYSCALL
bool
default y
config ZONE_DMA32
bool
default y

6
arch/x86_64/kernel/hpet.c
View file

@ -458,6 +458,11 @@ static cycle_t read_hpet(void)
return (cycle_t)readl(hpet_ptr);
}
static cycle_t __vsyscall_fn vread_hpet(void)
{
return readl((void __iomem *)fix_to_virt(VSYSCALL_HPET) + 0xf0);
}
struct clocksource clocksource_hpet = {
.name = "hpet",
.rating = 250,
@ -466,6 +471,7 @@ struct clocksource clocksource_hpet = {
.mult = 0, /* set below */
.shift = HPET_SHIFT,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
.vread = vread_hpet,
};
static int __init init_hpet_clocksource(void)

6
arch/x86_64/kernel/time.c
View file

@ -53,13 +53,7 @@ DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);
DEFINE_SPINLOCK(i8253_lock);
unsigned long vxtime_hz = PIT_TICK_RATE;
struct vxtime_data __vxtime __section_vxtime; /* for vsyscalls */
volatile unsigned long __jiffies __section_jiffies = INITIAL_JIFFIES;
struct timespec __xtime __section_xtime;
struct timezone __sys_tz __section_sys_tz;
unsigned long profile_pc(struct pt_regs *regs)
{

7
arch/x86_64/kernel/tsc.c
View file

@ -180,6 +180,12 @@ static cycle_t read_tsc(void)
return ret;
}
static cycle_t __vsyscall_fn vread_tsc(void)
{
cycle_t ret = (cycle_t)get_cycles_sync();
return ret;
}
static struct clocksource clocksource_tsc = {
.name = "tsc",
.rating = 300,
@ -188,6 +194,7 @@ static struct clocksource clocksource_tsc = {
.shift = 22,
.flags = CLOCK_SOURCE_IS_CONTINUOUS |
CLOCK_SOURCE_MUST_VERIFY,
.vread = vread_tsc,
};
void mark_tsc_unstable(void)

28
arch/x86_64/kernel/vmlinux.lds.S
View file

@ -88,31 +88,25 @@ SECTIONS
__vsyscall_0 = VSYSCALL_VIRT_ADDR;
. = ALIGN(CONFIG_X86_L1_CACHE_BYTES);
.xtime_lock : AT(VLOAD(.xtime_lock)) { *(.xtime_lock) }
xtime_lock = VVIRT(.xtime_lock);
.vxtime : AT(VLOAD(.vxtime)) { *(.vxtime) }
vxtime = VVIRT(.vxtime);
.vsyscall_fn : AT(VLOAD(.vsyscall_fn)) { *(.vsyscall_fn) }
. = ALIGN(CONFIG_X86_L1_CACHE_BYTES);
.vsyscall_gtod_data : AT(VLOAD(.vsyscall_gtod_data))
{ *(.vsyscall_gtod_data) }
vsyscall_gtod_data = VVIRT(.vsyscall_gtod_data);
.vgetcpu_mode : AT(VLOAD(.vgetcpu_mode)) { *(.vgetcpu_mode) }
vgetcpu_mode = VVIRT(.vgetcpu_mode);
.sys_tz : AT(VLOAD(.sys_tz)) { *(.sys_tz) }
sys_tz = VVIRT(.sys_tz);
.sysctl_vsyscall : AT(VLOAD(.sysctl_vsyscall)) { *(.sysctl_vsyscall) }
sysctl_vsyscall = VVIRT(.sysctl_vsyscall);
.xtime : AT(VLOAD(.xtime)) { *(.xtime) }
xtime = VVIRT(.xtime);
. = ALIGN(CONFIG_X86_L1_CACHE_BYTES);
.jiffies : AT(VLOAD(.jiffies)) { *(.jiffies) }
jiffies = VVIRT(.jiffies);
.vsyscall_1 ADDR(.vsyscall_0) + 1024: AT(VLOAD(.vsyscall_1)) { *(.vsyscall_1) }
.vsyscall_2 ADDR(.vsyscall_0) + 2048: AT(VLOAD(.vsyscall_2)) { *(.vsyscall_2) }
.vsyscall_3 ADDR(.vsyscall_0) + 3072: AT(VLOAD(.vsyscall_3)) { *(.vsyscall_3) }
.vsyscall_1 ADDR(.vsyscall_0) + 1024: AT(VLOAD(.vsyscall_1))
{ *(.vsyscall_1) }
.vsyscall_2 ADDR(.vsyscall_0) + 2048: AT(VLOAD(.vsyscall_2))
{ *(.vsyscall_2) }
.vsyscall_3 ADDR(.vsyscall_0) + 3072: AT(VLOAD(.vsyscall_3))
{ *(.vsyscall_3) }
. = VSYSCALL_VIRT_ADDR + 4096;

123
arch/x86_64/kernel/vsyscall.c
View file

@ -26,6 +26,7 @@
#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>
@ -34,6 +35,7 @@
#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>
@ -44,56 +46,41 @@
#define __vsyscall(nr) __attribute__ ((unused,__section__(".vsyscall_" #nr)))
#define __syscall_clobber "r11","rcx","memory"
int __sysctl_vsyscall __section_sysctl_vsyscall = 1;
seqlock_t __xtime_lock __section_xtime_lock = SEQLOCK_UNLOCKED;
struct vsyscall_gtod_data_t {
seqlock_t lock;
int sysctl_enabled;
struct timeval wall_time_tv;
struct timezone sys_tz;
cycle_t offset_base;
struct clocksource clock;
};
int __vgetcpu_mode __section_vgetcpu_mode;
#include <asm/unistd.h>
static __always_inline void timeval_normalize(struct timeval * tv)
struct vsyscall_gtod_data_t __vsyscall_gtod_data __section_vsyscall_gtod_data =
{
time_t __sec;
.lock = SEQLOCK_UNLOCKED,
.sysctl_enabled = 1,
};
__sec = tv->tv_usec / 1000000;
if (__sec) {
tv->tv_usec %= 1000000;
tv->tv_sec += __sec;
}
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 = *clock;
vsyscall_gtod_data.wall_time_tv.tv_sec = wall_time->tv_sec;
vsyscall_gtod_data.wall_time_tv.tv_usec = wall_time->tv_nsec/1000;
vsyscall_gtod_data.sys_tz = sys_tz;
write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags);
}
static __always_inline void do_vgettimeofday(struct timeval * tv)
{
long sequence, t;
unsigned long sec, usec;
do {
sequence = read_seqbegin(&__xtime_lock);
sec = __xtime.tv_sec;
usec = __xtime.tv_nsec / 1000;
if (__vxtime.mode != VXTIME_HPET) {
t = get_cycles_sync();
if (t < __vxtime.last_tsc)
t = __vxtime.last_tsc;
usec += ((t - __vxtime.last_tsc) *
__vxtime.tsc_quot) >> 32;
/* See comment in x86_64 do_gettimeofday. */
} else {
usec += ((readl((void __iomem *)
fix_to_virt(VSYSCALL_HPET) + 0xf0) -
__vxtime.last) * __vxtime.quot) >> 32;
}
} while (read_seqretry(&__xtime_lock, sequence));
tv->tv_sec = sec + usec / 1000000;
tv->tv_usec = usec % 1000000;
}
/* RED-PEN may want to readd seq locking, but then the variable should be write-once. */
/* 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 = __sys_tz;
*tz = __vsyscall_gtod_data.sys_tz;
}
static __always_inline int gettimeofday(struct timeval *tv, struct timezone *tz)
@ -101,7 +88,8 @@ 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 );
: "0" (__NR_gettimeofday),"D" (tv),"S" (tz)
: __syscall_clobber );
return ret;
}
@ -114,10 +102,44 @@ static __always_inline long time_syscall(long *t)
return secs;
}
static __always_inline void do_vgettimeofday(struct timeval * tv)
{
cycle_t now, base, mask, cycle_delta;
unsigned long seq, mult, shift, nsec_delta;
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,0);
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 = __vsyscall_gtod_data.wall_time_tv;
} while (read_seqretry(&__vsyscall_gtod_data.lock, seq));
/* calculate interval: */
cycle_delta = (now - base) & mask;
/* convert to nsecs: */
nsec_delta = (cycle_delta * mult) >> shift;
/* convert to usecs and add to timespec: */
tv->tv_usec += nsec_delta / NSEC_PER_USEC;
while (tv->tv_usec > USEC_PER_SEC) {
tv->tv_sec += 1;
tv->tv_usec -= USEC_PER_SEC;
}
}
int __vsyscall(0) vgettimeofday(struct timeval * tv, struct timezone * tz)
{
if (!__sysctl_vsyscall)
return gettimeofday(tv,tz);
if (tv)
do_vgettimeofday(tv);
if (tz)
@ -129,11 +151,11 @@ int __vsyscall(0) vgettimeofday(struct timeval * tv, struct timezone * tz)
* unlikely */
time_t __vsyscall(1) vtime(time_t *t)
{
if (!__sysctl_vsyscall)
if (unlikely(!__vsyscall_gtod_data.sysctl_enabled))
return time_syscall(t);
else if (t)
*t = __xtime.tv_sec;
return __xtime.tv_sec;
*t = __vsyscall_gtod_data.wall_time_tv.tv_sec;
return __vsyscall_gtod_data.wall_time_tv.tv_sec;
}
/* Fast way to get current CPU and node.
@ -210,7 +232,7 @@ static int vsyscall_sysctl_change(ctl_table *ctl, int write, struct file * filp,
ret = -ENOMEM;
goto out;
}
if (!sysctl_vsyscall) {
if (!vsyscall_gtod_data.sysctl_enabled) {
writew(SYSCALL, map1);
writew(SYSCALL, map2);
} else {
@ -232,7 +254,8 @@ static int vsyscall_sysctl_nostrat(ctl_table *t, int __user *name, int nlen,
static ctl_table kernel_table2[] = {
{ .ctl_name = 99, .procname = "vsyscall64",
.data = &sysctl_vsyscall, .maxlen = sizeof(int), .mode = 0644,
.data = &vsyscall_gtod_data.sysctl_enabled, .maxlen = sizeof(int),
.mode = 0644,
.strategy = vsyscall_sysctl_nostrat,
.proc_handler = vsyscall_sysctl_change },
{}

2
include/asm-x86_64/proto.h
View file

@ -45,9 +45,7 @@ extern u32 pmtmr_ioport;
#else
#define pmtmr_ioport 0
#endif
extern int sysctl_vsyscall;
extern int nohpet;
extern unsigned long vxtime_hz;
extern void early_printk(const char *fmt, ...) __attribute__((format(printf,1,2)));

1
include/asm-x86_64/timex.h
View file

@ -27,7 +27,6 @@ extern int read_current_timer(unsigned long *timer_value);
#define NS_SCALE 10 /* 2^10, carefully chosen */
#define US_SCALE 32 /* 2^32, arbitralrily chosen */
extern struct vxtime_data vxtime;
extern void mark_tsc_unstable(void);
extern void set_cyc2ns_scale(unsigned long khz);
#endif

29
include/asm-x86_64/vsyscall.h
View file

@ -16,46 +16,27 @@ enum vsyscall_num {
#ifdef __KERNEL__
#include <linux/seqlock.h>
#define __section_vxtime __attribute__ ((unused, __section__ (".vxtime"), aligned(16)))
#define __section_vgetcpu_mode __attribute__ ((unused, __section__ (".vgetcpu_mode"), aligned(16)))
#define __section_jiffies __attribute__ ((unused, __section__ (".jiffies"), aligned(16)))
#define __section_sys_tz __attribute__ ((unused, __section__ (".sys_tz"), aligned(16)))
#define __section_sysctl_vsyscall __attribute__ ((unused, __section__ (".sysctl_vsyscall"), aligned(16)))
#define __section_xtime __attribute__ ((unused, __section__ (".xtime"), aligned(16)))
#define __section_xtime_lock __attribute__ ((unused, __section__ (".xtime_lock"), aligned(16)))
#define VXTIME_TSC 1
#define VXTIME_HPET 2
#define VXTIME_PMTMR 3
/* Definitions for CONFIG_GENERIC_TIME definitions */
#define __section_vsyscall_gtod_data __attribute__ \
((unused, __section__ (".vsyscall_gtod_data"),aligned(16)))
#define __vsyscall_fn __attribute__ ((unused,__section__(".vsyscall_fn")))
#define VGETCPU_RDTSCP 1
#define VGETCPU_LSL 2
struct vxtime_data {
long hpet_address; /* HPET base address */
int last;
unsigned long last_tsc;
long quot;
long tsc_quot;
int mode;
};
#define hpet_readl(a) readl((const void __iomem *)fix_to_virt(FIX_HPET_BASE) + a)
#define hpet_writel(d,a) writel(d, (void __iomem *)fix_to_virt(FIX_HPET_BASE) + a)
/* vsyscall space (readonly) */
extern struct vxtime_data __vxtime;
extern int __vgetcpu_mode;
extern struct timespec __xtime;
extern volatile unsigned long __jiffies;
extern struct timezone __sys_tz;
extern seqlock_t __xtime_lock;
/* kernel space (writeable) */
extern struct vxtime_data vxtime;
extern int vgetcpu_mode;
extern struct timezone sys_tz;
extern int sysctl_vsyscall;
extern struct vsyscall_gtod_data_t vsyscall_gtod_data;
#endif /* __KERNEL__ */