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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datapage.h (4219B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2#ifndef __VDSO_DATAPAGE_H
      3#define __VDSO_DATAPAGE_H
      4
      5#ifndef __ASSEMBLY__
      6
      7#include <linux/compiler.h>
      8#include <uapi/linux/time.h>
      9#include <uapi/linux/types.h>
     10#include <uapi/asm-generic/errno-base.h>
     11
     12#include <vdso/bits.h>
     13#include <vdso/clocksource.h>
     14#include <vdso/ktime.h>
     15#include <vdso/limits.h>
     16#include <vdso/math64.h>
     17#include <vdso/processor.h>
     18#include <vdso/time.h>
     19#include <vdso/time32.h>
     20#include <vdso/time64.h>
     21
     22#ifdef CONFIG_ARCH_HAS_VDSO_DATA
     23#include <asm/vdso/data.h>
     24#else
     25struct arch_vdso_data {};
     26#endif
     27
     28#define VDSO_BASES	(CLOCK_TAI + 1)
     29#define VDSO_HRES	(BIT(CLOCK_REALTIME)		| \
     30			 BIT(CLOCK_MONOTONIC)		| \
     31			 BIT(CLOCK_BOOTTIME)		| \
     32			 BIT(CLOCK_TAI))
     33#define VDSO_COARSE	(BIT(CLOCK_REALTIME_COARSE)	| \
     34			 BIT(CLOCK_MONOTONIC_COARSE))
     35#define VDSO_RAW	(BIT(CLOCK_MONOTONIC_RAW))
     36
     37#define CS_HRES_COARSE	0
     38#define CS_RAW		1
     39#define CS_BASES	(CS_RAW + 1)
     40
     41/**
     42 * struct vdso_timestamp - basetime per clock_id
     43 * @sec:	seconds
     44 * @nsec:	nanoseconds
     45 *
     46 * There is one vdso_timestamp object in vvar for each vDSO-accelerated
     47 * clock_id. For high-resolution clocks, this encodes the time
     48 * corresponding to vdso_data.cycle_last. For coarse clocks this encodes
     49 * the actual time.
     50 *
     51 * To be noticed that for highres clocks nsec is left-shifted by
     52 * vdso_data.cs[x].shift.
     53 */
     54struct vdso_timestamp {
     55	u64	sec;
     56	u64	nsec;
     57};
     58
     59/**
     60 * struct vdso_data - vdso datapage representation
     61 * @seq:		timebase sequence counter
     62 * @clock_mode:		clock mode
     63 * @cycle_last:		timebase at clocksource init
     64 * @mask:		clocksource mask
     65 * @mult:		clocksource multiplier
     66 * @shift:		clocksource shift
     67 * @basetime[clock_id]:	basetime per clock_id
     68 * @offset[clock_id]:	time namespace offset per clock_id
     69 * @tz_minuteswest:	minutes west of Greenwich
     70 * @tz_dsttime:		type of DST correction
     71 * @hrtimer_res:	hrtimer resolution
     72 * @__unused:		unused
     73 * @arch_data:		architecture specific data (optional, defaults
     74 *			to an empty struct)
     75 *
     76 * vdso_data will be accessed by 64 bit and compat code at the same time
     77 * so we should be careful before modifying this structure.
     78 *
     79 * @basetime is used to store the base time for the system wide time getter
     80 * VVAR page.
     81 *
     82 * @offset is used by the special time namespace VVAR pages which are
     83 * installed instead of the real VVAR page. These namespace pages must set
     84 * @seq to 1 and @clock_mode to VDSO_CLOCKMODE_TIMENS to force the code into
     85 * the time namespace slow path. The namespace aware functions retrieve the
     86 * real system wide VVAR page, read host time and add the per clock offset.
     87 * For clocks which are not affected by time namespace adjustment the
     88 * offset must be zero.
     89 */
     90struct vdso_data {
     91	u32			seq;
     92
     93	s32			clock_mode;
     94	u64			cycle_last;
     95	u64			mask;
     96	u32			mult;
     97	u32			shift;
     98
     99	union {
    100		struct vdso_timestamp	basetime[VDSO_BASES];
    101		struct timens_offset	offset[VDSO_BASES];
    102	};
    103
    104	s32			tz_minuteswest;
    105	s32			tz_dsttime;
    106	u32			hrtimer_res;
    107	u32			__unused;
    108
    109	struct arch_vdso_data	arch_data;
    110};
    111
    112/*
    113 * We use the hidden visibility to prevent the compiler from generating a GOT
    114 * relocation. Not only is going through a GOT useless (the entry couldn't and
    115 * must not be overridden by another library), it does not even work: the linker
    116 * cannot generate an absolute address to the data page.
    117 *
    118 * With the hidden visibility, the compiler simply generates a PC-relative
    119 * relocation, and this is what we need.
    120 */
    121extern struct vdso_data _vdso_data[CS_BASES] __attribute__((visibility("hidden")));
    122extern struct vdso_data _timens_data[CS_BASES] __attribute__((visibility("hidden")));
    123
    124/*
    125 * The generic vDSO implementation requires that gettimeofday.h
    126 * provides:
    127 * - __arch_get_vdso_data(): to get the vdso datapage.
    128 * - __arch_get_hw_counter(): to get the hw counter based on the
    129 *   clock_mode.
    130 * - gettimeofday_fallback(): fallback for gettimeofday.
    131 * - clock_gettime_fallback(): fallback for clock_gettime.
    132 * - clock_getres_fallback(): fallback for clock_getres.
    133 */
    134#ifdef ENABLE_COMPAT_VDSO
    135#include <asm/vdso/compat_gettimeofday.h>
    136#else
    137#include <asm/vdso/gettimeofday.h>
    138#endif /* ENABLE_COMPAT_VDSO */
    139
    140#endif /* !__ASSEMBLY__ */
    141
    142#endif /* __VDSO_DATAPAGE_H */