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1/* SPDX-License-Identifier: GPL-2.0 */2#ifndef __VDSO_DATAPAGE_H3#define __VDSO_DATAPAGE_H4 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_DATA23#include <asm/vdso/data.h>24#else25struct arch_vdso_data {};26#endif27 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 038#define CS_RAW 139#define CS_BASES (CS_RAW + 1)40 41/**42 * struct vdso_timestamp - basetime per clock_id43 * @sec: seconds44 * @nsec: nanoseconds45 *46 * There is one vdso_timestamp object in vvar for each vDSO-accelerated47 * clock_id. For high-resolution clocks, this encodes the time48 * corresponding to vdso_data.cycle_last. For coarse clocks this encodes49 * the actual time.50 *51 * To be noticed that for highres clocks nsec is left-shifted by52 * vdso_data.cs[x].shift.53 */54struct vdso_timestamp {55 u64 sec;56 u64 nsec;57};58 59/**60 * struct vdso_data - vdso datapage representation61 * @seq: timebase sequence counter62 * @clock_mode: clock mode63 * @cycle_last: timebase at clocksource init64 * @max_cycles: maximum cycles which won't overflow 64bit multiplication65 * @mask: clocksource mask66 * @mult: clocksource multiplier67 * @shift: clocksource shift68 * @basetime[clock_id]: basetime per clock_id69 * @offset[clock_id]: time namespace offset per clock_id70 * @tz_minuteswest: minutes west of Greenwich71 * @tz_dsttime: type of DST correction72 * @hrtimer_res: hrtimer resolution73 * @__unused: unused74 * @arch_data: architecture specific data (optional, defaults75 * to an empty struct)76 *77 * vdso_data will be accessed by 64 bit and compat code at the same time78 * so we should be careful before modifying this structure.79 *80 * The ordering of the struct members is optimized to have fast access to the81 * often required struct members which are related to CLOCK_REALTIME and82 * CLOCK_MONOTONIC. This information is stored in the first cache lines.83 *84 * @basetime is used to store the base time for the system wide time getter85 * VVAR page.86 *87 * @offset is used by the special time namespace VVAR pages which are88 * installed instead of the real VVAR page. These namespace pages must set89 * @seq to 1 and @clock_mode to VDSO_CLOCKMODE_TIMENS to force the code into90 * the time namespace slow path. The namespace aware functions retrieve the91 * real system wide VVAR page, read host time and add the per clock offset.92 * For clocks which are not affected by time namespace adjustment the93 * offset must be zero.94 */95struct vdso_data {96 u32 seq;97 98 s32 clock_mode;99 u64 cycle_last;100#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT101 u64 max_cycles;102#endif103 u64 mask;104 u32 mult;105 u32 shift;106 107 union {108 struct vdso_timestamp basetime[VDSO_BASES];109 struct timens_offset offset[VDSO_BASES];110 };111 112 s32 tz_minuteswest;113 s32 tz_dsttime;114 u32 hrtimer_res;115 u32 __unused;116 117 struct arch_vdso_data arch_data;118};119 120/**121 * struct vdso_rng_data - vdso RNG state information122 * @generation: counter representing the number of RNG reseeds123 * @is_ready: boolean signaling whether the RNG is initialized124 */125struct vdso_rng_data {126 u64 generation;127 u8 is_ready;128};129 130/*131 * We use the hidden visibility to prevent the compiler from generating a GOT132 * relocation. Not only is going through a GOT useless (the entry couldn't and133 * must not be overridden by another library), it does not even work: the linker134 * cannot generate an absolute address to the data page.135 *136 * With the hidden visibility, the compiler simply generates a PC-relative137 * relocation, and this is what we need.138 */139extern struct vdso_data _vdso_data[CS_BASES] __attribute__((visibility("hidden")));140extern struct vdso_data _timens_data[CS_BASES] __attribute__((visibility("hidden")));141extern struct vdso_rng_data _vdso_rng_data __attribute__((visibility("hidden")));142 143/**144 * union vdso_data_store - Generic vDSO data page145 */146union vdso_data_store {147 struct vdso_data data[CS_BASES];148 u8 page[1U << CONFIG_PAGE_SHIFT];149};150 151/*152 * The generic vDSO implementation requires that gettimeofday.h153 * provides:154 * - __arch_get_vdso_data(): to get the vdso datapage.155 * - __arch_get_hw_counter(): to get the hw counter based on the156 * clock_mode.157 * - gettimeofday_fallback(): fallback for gettimeofday.158 * - clock_gettime_fallback(): fallback for clock_gettime.159 * - clock_getres_fallback(): fallback for clock_getres.160 */161#ifdef ENABLE_COMPAT_VDSO162#include <asm/vdso/compat_gettimeofday.h>163#else164#include <asm/vdso/gettimeofday.h>165#endif /* ENABLE_COMPAT_VDSO */166 167#endif /* !__ASSEMBLY__ */168 169#endif /* __VDSO_DATAPAGE_H */170