cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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pvclock.h (2702B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2#ifndef _ASM_X86_PVCLOCK_H
      3#define _ASM_X86_PVCLOCK_H
      4
      5#include <asm/clocksource.h>
      6#include <asm/pvclock-abi.h>
      7
      8/* some helper functions for xen and kvm pv clock sources */
      9u64 pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
     10u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src);
     11void pvclock_set_flags(u8 flags);
     12unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
     13void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
     14			    struct pvclock_vcpu_time_info *vcpu,
     15			    struct timespec64 *ts);
     16void pvclock_resume(void);
     17
     18void pvclock_touch_watchdogs(void);
     19
     20static __always_inline
     21unsigned pvclock_read_begin(const struct pvclock_vcpu_time_info *src)
     22{
     23	unsigned version = src->version & ~1;
     24	/* Make sure that the version is read before the data. */
     25	virt_rmb();
     26	return version;
     27}
     28
     29static __always_inline
     30bool pvclock_read_retry(const struct pvclock_vcpu_time_info *src,
     31			unsigned version)
     32{
     33	/* Make sure that the version is re-read after the data. */
     34	virt_rmb();
     35	return unlikely(version != src->version);
     36}
     37
     38/*
     39 * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
     40 * yielding a 64-bit result.
     41 */
     42static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
     43{
     44	u64 product;
     45#ifdef __i386__
     46	u32 tmp1, tmp2;
     47#else
     48	ulong tmp;
     49#endif
     50
     51	if (shift < 0)
     52		delta >>= -shift;
     53	else
     54		delta <<= shift;
     55
     56#ifdef __i386__
     57	__asm__ (
     58		"mul  %5       ; "
     59		"mov  %4,%%eax ; "
     60		"mov  %%edx,%4 ; "
     61		"mul  %5       ; "
     62		"xor  %5,%5    ; "
     63		"add  %4,%%eax ; "
     64		"adc  %5,%%edx ; "
     65		: "=A" (product), "=r" (tmp1), "=r" (tmp2)
     66		: "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
     67#elif defined(__x86_64__)
     68	__asm__ (
     69		"mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"
     70		: [lo]"=a"(product),
     71		  [hi]"=d"(tmp)
     72		: "0"(delta),
     73		  [mul_frac]"rm"((u64)mul_frac));
     74#else
     75#error implement me!
     76#endif
     77
     78	return product;
     79}
     80
     81static __always_inline
     82u64 __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src, u64 tsc)
     83{
     84	u64 delta = tsc - src->tsc_timestamp;
     85	u64 offset = pvclock_scale_delta(delta, src->tsc_to_system_mul,
     86					     src->tsc_shift);
     87	return src->system_time + offset;
     88}
     89
     90struct pvclock_vsyscall_time_info {
     91	struct pvclock_vcpu_time_info pvti;
     92} __attribute__((__aligned__(SMP_CACHE_BYTES)));
     93
     94#define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info)
     95
     96#ifdef CONFIG_PARAVIRT_CLOCK
     97void pvclock_set_pvti_cpu0_va(struct pvclock_vsyscall_time_info *pvti);
     98struct pvclock_vsyscall_time_info *pvclock_get_pvti_cpu0_va(void);
     99#else
    100static inline struct pvclock_vsyscall_time_info *pvclock_get_pvti_cpu0_va(void)
    101{
    102	return NULL;
    103}
    104#endif
    105
    106#endif /* _ASM_X86_PVCLOCK_H */