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/align.h> 13 #include <vdso/bits.h> 14 #include <vdso/clocksource.h> 15 #include <vdso/ktime.h> 16 #include <vdso/limits.h> 17 #include <vdso/math64.h> 18 #include <vdso/page.h> 19 #include <vdso/processor.h> 20 #include <vdso/time.h> 21 #include <vdso/time32.h> 22 #include <vdso/time64.h> 23 24 #ifdef CONFIG_ARCH_HAS_VDSO_TIME_DATA 25 #include <asm/vdso/time_data.h> 26 #else 27 struct arch_vdso_time_data {}; 28 #endif 29 30 #if defined(CONFIG_ARCH_HAS_VDSO_ARCH_DATA) 31 #include <asm/vdso/arch_data.h> 32 #elif defined(CONFIG_GENERIC_VDSO_DATA_STORE) 33 struct vdso_arch_data { 34 /* Needed for the generic code, never actually used at runtime */ 35 char __unused; 36 }; 37 #endif 38 39 #define VDSO_BASES (CLOCK_TAI + 1) 40 #define VDSO_HRES (BIT(CLOCK_REALTIME) | \ 41 BIT(CLOCK_MONOTONIC) | \ 42 BIT(CLOCK_BOOTTIME) | \ 43 BIT(CLOCK_TAI)) 44 #define VDSO_COARSE (BIT(CLOCK_REALTIME_COARSE) | \ 45 BIT(CLOCK_MONOTONIC_COARSE)) 46 #define VDSO_RAW (BIT(CLOCK_MONOTONIC_RAW)) 47 48 #define CS_HRES_COARSE 0 49 #define CS_RAW 1 50 #define CS_BASES (CS_RAW + 1) 51 52 /** 53 * struct vdso_timestamp - basetime per clock_id 54 * @sec: seconds 55 * @nsec: nanoseconds 56 * 57 * There is one vdso_timestamp object in vvar for each vDSO-accelerated 58 * clock_id. For high-resolution clocks, this encodes the time 59 * corresponding to vdso_time_data.cycle_last. For coarse clocks this encodes 60 * the actual time. 61 * 62 * To be noticed that for highres clocks nsec is left-shifted by 63 * vdso_time_data[x].shift. 64 */ 65 struct vdso_timestamp { 66 u64 sec; 67 u64 nsec; 68 }; 69 70 /** 71 * struct vdso_time_data - vdso datapage representation 72 * @seq: timebase sequence counter 73 * @clock_mode: clock mode 74 * @cycle_last: timebase at clocksource init 75 * @max_cycles: maximum cycles which won't overflow 64bit multiplication 76 * @mask: clocksource mask 77 * @mult: clocksource multiplier 78 * @shift: clocksource shift 79 * @basetime[clock_id]: basetime per clock_id 80 * @offset[clock_id]: time namespace offset per clock_id 81 * @tz_minuteswest: minutes west of Greenwich 82 * @tz_dsttime: type of DST correction 83 * @hrtimer_res: hrtimer resolution 84 * @__unused: unused 85 * @arch_data: architecture specific data (optional, defaults 86 * to an empty struct) 87 * 88 * vdso_time_data will be accessed by 64 bit and compat code at the same time 89 * so we should be careful before modifying this structure. 90 * 91 * The ordering of the struct members is optimized to have fast access to the 92 * often required struct members which are related to CLOCK_REALTIME and 93 * CLOCK_MONOTONIC. This information is stored in the first cache lines. 94 * 95 * @basetime is used to store the base time for the system wide time getter 96 * VVAR page. 97 * 98 * @offset is used by the special time namespace VVAR pages which are 99 * installed instead of the real VVAR page. These namespace pages must set 100 * @seq to 1 and @clock_mode to VDSO_CLOCKMODE_TIMENS to force the code into 101 * the time namespace slow path. The namespace aware functions retrieve the 102 * real system wide VVAR page, read host time and add the per clock offset. 103 * For clocks which are not affected by time namespace adjustment the 104 * offset must be zero. 105 */ 106 struct vdso_time_data { 107 u32 seq; 108 109 s32 clock_mode; 110 u64 cycle_last; 111 #ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT 112 u64 max_cycles; 113 #endif 114 u64 mask; 115 u32 mult; 116 u32 shift; 117 118 union { 119 struct vdso_timestamp basetime[VDSO_BASES]; 120 struct timens_offset offset[VDSO_BASES]; 121 }; 122 123 s32 tz_minuteswest; 124 s32 tz_dsttime; 125 u32 hrtimer_res; 126 u32 __unused; 127 128 struct arch_vdso_time_data arch_data; 129 }; 130 131 /** 132 * struct vdso_rng_data - vdso RNG state information 133 * @generation: counter representing the number of RNG reseeds 134 * @is_ready: boolean signaling whether the RNG is initialized 135 */ 136 struct vdso_rng_data { 137 u64 generation; 138 u8 is_ready; 139 }; 140 141 /* 142 * We use the hidden visibility to prevent the compiler from generating a GOT 143 * relocation. Not only is going through a GOT useless (the entry couldn't and 144 * must not be overridden by another library), it does not even work: the linker 145 * cannot generate an absolute address to the data page. 146 * 147 * With the hidden visibility, the compiler simply generates a PC-relative 148 * relocation, and this is what we need. 149 */ 150 #ifdef CONFIG_GENERIC_VDSO_DATA_STORE 151 extern struct vdso_time_data vdso_u_time_data[CS_BASES] __attribute__((visibility("hidden"))); 152 extern struct vdso_rng_data vdso_u_rng_data __attribute__((visibility("hidden"))); 153 extern struct vdso_arch_data vdso_u_arch_data __attribute__((visibility("hidden"))); 154 155 extern struct vdso_time_data *vdso_k_time_data; 156 extern struct vdso_rng_data *vdso_k_rng_data; 157 extern struct vdso_arch_data *vdso_k_arch_data; 158 159 #define VDSO_ARCH_DATA_SIZE ALIGN(sizeof(struct vdso_arch_data), PAGE_SIZE) 160 #define VDSO_ARCH_DATA_PAGES (VDSO_ARCH_DATA_SIZE >> PAGE_SHIFT) 161 162 enum vdso_pages { 163 VDSO_TIME_PAGE_OFFSET, 164 VDSO_TIMENS_PAGE_OFFSET, 165 VDSO_RNG_PAGE_OFFSET, 166 VDSO_ARCH_PAGES_START, 167 VDSO_ARCH_PAGES_END = VDSO_ARCH_PAGES_START + VDSO_ARCH_DATA_PAGES - 1, 168 VDSO_NR_PAGES 169 }; 170 171 #endif /* CONFIG_GENERIC_VDSO_DATA_STORE */ 172 173 /* 174 * The generic vDSO implementation requires that gettimeofday.h 175 * provides: 176 * - __arch_get_hw_counter(): to get the hw counter based on the 177 * clock_mode. 178 * - gettimeofday_fallback(): fallback for gettimeofday. 179 * - clock_gettime_fallback(): fallback for clock_gettime. 180 * - clock_getres_fallback(): fallback for clock_getres. 181 */ 182 #ifdef ENABLE_COMPAT_VDSO 183 #include <asm/vdso/compat_gettimeofday.h> 184 #else 185 #include <asm/vdso/gettimeofday.h> 186 #endif /* ENABLE_COMPAT_VDSO */ 187 188 #else /* !__ASSEMBLY__ */ 189 190 #ifdef CONFIG_VDSO_GETRANDOM 191 #define __vdso_u_rng_data PROVIDE(vdso_u_rng_data = vdso_u_data + 2 * PAGE_SIZE); 192 #else 193 #define __vdso_u_rng_data 194 #endif 195 196 #ifdef CONFIG_ARCH_HAS_VDSO_ARCH_DATA 197 #define __vdso_u_arch_data PROVIDE(vdso_u_arch_data = vdso_u_data + 3 * PAGE_SIZE); 198 #else 199 #define __vdso_u_arch_data 200 #endif 201 202 #define VDSO_VVAR_SYMS \ 203 PROVIDE(vdso_u_data = . - __VDSO_PAGES * PAGE_SIZE); \ 204 PROVIDE(vdso_u_time_data = vdso_u_data); \ 205 __vdso_u_rng_data \ 206 __vdso_u_arch_data \ 207 208 209 #endif /* !__ASSEMBLY__ */ 210 211 #endif /* __VDSO_DATAPAGE_H */ 212