mirror of
https://github.com/torvalds/linux.git
synced 2024-12-20 18:11:47 +00:00
d63285e94a
Implement reset of kernel watchdogs at pvclock read time. This avoids adding special code to every watchdog. This is possible for watchdogs which measure time based on sched_clock() or ktime_get() variants. Suggested by Don Zickus. Acked-by: Don Zickus <dzickus@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
108 lines
2.8 KiB
C
108 lines
2.8 KiB
C
#ifndef _ASM_X86_PVCLOCK_H
|
|
#define _ASM_X86_PVCLOCK_H
|
|
|
|
#include <linux/clocksource.h>
|
|
#include <asm/pvclock-abi.h>
|
|
|
|
/* some helper functions for xen and kvm pv clock sources */
|
|
cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
|
|
u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src);
|
|
void pvclock_set_flags(u8 flags);
|
|
unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
|
|
void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
|
|
struct pvclock_vcpu_time_info *vcpu,
|
|
struct timespec *ts);
|
|
void pvclock_resume(void);
|
|
|
|
void pvclock_touch_watchdogs(void);
|
|
|
|
/*
|
|
* Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
|
|
* yielding a 64-bit result.
|
|
*/
|
|
static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
|
|
{
|
|
u64 product;
|
|
#ifdef __i386__
|
|
u32 tmp1, tmp2;
|
|
#else
|
|
ulong tmp;
|
|
#endif
|
|
|
|
if (shift < 0)
|
|
delta >>= -shift;
|
|
else
|
|
delta <<= shift;
|
|
|
|
#ifdef __i386__
|
|
__asm__ (
|
|
"mul %5 ; "
|
|
"mov %4,%%eax ; "
|
|
"mov %%edx,%4 ; "
|
|
"mul %5 ; "
|
|
"xor %5,%5 ; "
|
|
"add %4,%%eax ; "
|
|
"adc %5,%%edx ; "
|
|
: "=A" (product), "=r" (tmp1), "=r" (tmp2)
|
|
: "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
|
|
#elif defined(__x86_64__)
|
|
__asm__ (
|
|
"mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
|
|
: [lo]"=a"(product),
|
|
[hi]"=d"(tmp)
|
|
: "0"(delta),
|
|
[mul_frac]"rm"((u64)mul_frac));
|
|
#else
|
|
#error implement me!
|
|
#endif
|
|
|
|
return product;
|
|
}
|
|
|
|
static __always_inline
|
|
u64 pvclock_get_nsec_offset(const struct pvclock_vcpu_time_info *src)
|
|
{
|
|
u64 delta = __native_read_tsc() - src->tsc_timestamp;
|
|
return pvclock_scale_delta(delta, src->tsc_to_system_mul,
|
|
src->tsc_shift);
|
|
}
|
|
|
|
static __always_inline
|
|
unsigned __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src,
|
|
cycle_t *cycles, u8 *flags)
|
|
{
|
|
unsigned version;
|
|
cycle_t ret, offset;
|
|
u8 ret_flags;
|
|
|
|
version = src->version;
|
|
/* Note: emulated platforms which do not advertise SSE2 support
|
|
* result in kvmclock not using the necessary RDTSC barriers.
|
|
* Without barriers, it is possible that RDTSC instruction reads from
|
|
* the time stamp counter outside rdtsc_barrier protected section
|
|
* below, resulting in violation of monotonicity.
|
|
*/
|
|
rdtsc_barrier();
|
|
offset = pvclock_get_nsec_offset(src);
|
|
ret = src->system_time + offset;
|
|
ret_flags = src->flags;
|
|
rdtsc_barrier();
|
|
|
|
*cycles = ret;
|
|
*flags = ret_flags;
|
|
return version;
|
|
}
|
|
|
|
struct pvclock_vsyscall_time_info {
|
|
struct pvclock_vcpu_time_info pvti;
|
|
} __attribute__((__aligned__(SMP_CACHE_BYTES)));
|
|
|
|
#define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info)
|
|
#define PVCLOCK_VSYSCALL_NR_PAGES (((NR_CPUS-1)/(PAGE_SIZE/PVTI_SIZE))+1)
|
|
|
|
int __init pvclock_init_vsyscall(struct pvclock_vsyscall_time_info *i,
|
|
int size);
|
|
struct pvclock_vcpu_time_info *pvclock_get_vsyscall_time_info(int cpu);
|
|
|
|
#endif /* _ASM_X86_PVCLOCK_H */
|