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/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef CPU_X86_TSC_H
#define CPU_X86_TSC_H
#include <stdint.h>
#if CONFIG(TSC_SYNC_MFENCE)
#define TSC_SYNC "mfence\n"
#elif CONFIG(TSC_SYNC_LFENCE)
#define TSC_SYNC "lfence\n"
#else
#define TSC_SYNC
#endif
struct tsc_struct {
unsigned int lo;
unsigned int hi;
};
typedef struct tsc_struct tsc_t;
static inline tsc_t rdtsc(void)
{
tsc_t res;
asm volatile (
TSC_SYNC
"rdtsc"
: "=a" (res.lo), "=d"(res.hi) /* outputs */
);
return res;
}
/* Simple 32- to 64-bit multiplication. Uses 16-bit words to avoid overflow.
* This code is used to prevent use of libgcc's umoddi3.
*/
static inline void multiply_to_tsc(tsc_t *const tsc, const u32 a, const u32 b)
{
tsc->lo = (a & 0xffff) * (b & 0xffff);
tsc->hi = ((tsc->lo >> 16)
+ ((a & 0xffff) * (b >> 16))
+ ((b & 0xffff) * (a >> 16)));
tsc->lo = ((tsc->hi & 0xffff) << 16) | (tsc->lo & 0xffff);
tsc->hi = ((a >> 16) * (b >> 16)) + (tsc->hi >> 16);
}
static inline uint64_t tsc_to_uint64(tsc_t tstamp)
{
return (((uint64_t)tstamp.hi) << 32) + tstamp.lo;
}
static inline unsigned long long rdtscll(void)
{
return tsc_to_uint64(rdtsc());
}
/* Provided by CPU/chipset code for the TSC rate in MHz. */
unsigned long tsc_freq_mhz(void);
static inline int tsc_constant_rate(void)
{
return !CONFIG(UNKNOWN_TSC_RATE);
}
#endif /* CPU_X86_TSC_H */
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