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 (2537B)

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