x86: remove get_cycles_sync

rdtsc is now speculation-safe, so no need for the sync variants of
the APIs.

[ mingo@elte.hu: removed the nsec_barrier() complication. ]

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Andi Kleen 2008-01-30 13:32:39 +01:00 committed by Ingo Molnar
parent f06e4ec1c1
commit 6d63de8dbc
4 changed files with 17 additions and 61 deletions

View file

@ -83,7 +83,7 @@ unsigned long __init native_calculate_cpu_khz(void)
rdtscl(tsc_start);
do {
rdmsrl(MSR_K7_PERFCTR0 + i, pmc_now);
tsc_now = get_cycles_sync();
tsc_now = get_cycles();
} while ((tsc_now - tsc_start) < TICK_COUNT);
local_irq_restore(flags);

View file

@ -181,12 +181,12 @@ static unsigned long __init tsc_read_refs(unsigned long *pm,
int i;
for (i = 0; i < MAX_RETRIES; i++) {
t1 = get_cycles_sync();
t1 = get_cycles();
if (hpet)
*hpet = hpet_readl(HPET_COUNTER) & 0xFFFFFFFF;
else
*pm = acpi_pm_read_early();
t2 = get_cycles_sync();
t2 = get_cycles();
if ((t2 - t1) < SMI_TRESHOLD)
return t2;
}
@ -210,9 +210,9 @@ void __init tsc_calibrate(void)
outb(0xb0, 0x43);
outb((CLOCK_TICK_RATE / (1000 / 50)) & 0xff, 0x42);
outb((CLOCK_TICK_RATE / (1000 / 50)) >> 8, 0x42);
tr1 = get_cycles_sync();
tr1 = get_cycles();
while ((inb(0x61) & 0x20) == 0);
tr2 = get_cycles_sync();
tr2 = get_cycles();
tsc2 = tsc_read_refs(&pm2, hpet ? &hpet2 : NULL);
@ -300,13 +300,13 @@ __setup("notsc", notsc_setup);
/* clock source code: */
static cycle_t read_tsc(void)
{
cycle_t ret = (cycle_t)get_cycles_sync();
cycle_t ret = (cycle_t)get_cycles();
return ret;
}
static cycle_t __vsyscall_fn vread_tsc(void)
{
cycle_t ret = (cycle_t)vget_cycles_sync();
cycle_t ret = (cycle_t)vget_cycles();
return ret;
}

View file

@ -46,7 +46,7 @@ static __cpuinit void check_tsc_warp(void)
cycles_t start, now, prev, end;
int i;
start = get_cycles_sync();
start = get_cycles();
/*
* The measurement runs for 20 msecs:
*/
@ -61,7 +61,7 @@ static __cpuinit void check_tsc_warp(void)
*/
__raw_spin_lock(&sync_lock);
prev = last_tsc;
now = get_cycles_sync();
now = get_cycles();
last_tsc = now;
__raw_spin_unlock(&sync_lock);

View file

@ -36,62 +36,18 @@ static inline cycles_t get_cycles(void)
return ret;
}
/* Like get_cycles, but make sure the CPU is synchronized. */
static __always_inline cycles_t __get_cycles_sync(void)
static inline cycles_t vget_cycles(void)
{
unsigned long long ret;
unsigned eax, edx;
/*
* Use RDTSCP if possible; it is guaranteed to be synchronous
* and doesn't cause a VMEXIT on Hypervisors
* We only do VDSOs on TSC capable CPUs, so this shouldnt
* access boot_cpu_data (which is not VDSO-safe):
*/
alternative_io(ASM_NOP3, ".byte 0x0f,0x01,0xf9", X86_FEATURE_RDTSCP,
ASM_OUTPUT2("=a" (eax), "=d" (edx)),
"a" (0U), "d" (0U) : "ecx", "memory");
ret = (((unsigned long long)edx) << 32) | ((unsigned long long)eax);
if (ret)
return ret;
/*
* Don't do an additional sync on CPUs where we know
* RDTSC is already synchronous:
*/
alternative_io("cpuid", ASM_NOP2, X86_FEATURE_SYNC_RDTSC,
"=a" (eax), "0" (1) : "ebx","ecx","edx","memory");
return 0;
}
static __always_inline cycles_t get_cycles_sync(void)
{
unsigned long long ret;
ret = __get_cycles_sync();
if (!ret)
rdtscll(ret);
return ret;
}
#ifdef CONFIG_PARAVIRT
/*
* For paravirt guests, some functionalities are executed through function
* pointers in the various pvops structures.
* These function pointers exist inside the kernel and can not
* be accessed by user space. To avoid this, we make a copy of the
* get_cycles_sync (called in kernel) but force the use of native_read_tsc.
* Ideally, the guest should set up it's own clock and vread
*/
static __always_inline long long vget_cycles_sync(void)
{
unsigned long long ret;
ret = __get_cycles_sync();
if (!ret)
ret = native_read_tsc();
return ret;
}
#else
# define vget_cycles_sync() get_cycles_sync()
#ifndef CONFIG_X86_TSC
if (!cpu_has_tsc)
return 0;
#endif
return (cycles_t) native_read_tsc();
}
extern void tsc_init(void);
extern void mark_tsc_unstable(char *reason);