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/bits.h> 9 #include <uapi/linux/time.h> 10 #include <uapi/linux/types.h> 11 #include <uapi/asm-generic/errno-base.h> 12 13 #include <vdso/align.h> 14 #include <vdso/bits.h> 15 #include <vdso/cache.h> 16 #include <vdso/clocksource.h> 17 #include <vdso/ktime.h> 18 #include <vdso/limits.h> 19 #include <vdso/math64.h> 20 #include <vdso/page.h> 21 #include <vdso/processor.h> 22 #include <vdso/time.h> 23 #include <vdso/time32.h> 24 #include <vdso/time64.h> 25 26 #ifdef CONFIG_ARCH_HAS_VDSO_TIME_DATA 27 #include <asm/vdso/time_data.h> 28 #else 29 struct arch_vdso_time_data {}; 30 #endif 31 32 #if defined(CONFIG_ARCH_HAS_VDSO_ARCH_DATA) 33 #include <asm/vdso/arch_data.h> 34 #elif defined(CONFIG_GENERIC_VDSO_DATA_STORE) 35 struct vdso_arch_data { 36 /* Needed for the generic code, never actually used at runtime */ 37 char __unused; 38 }; 39 #endif 40 41 #define VDSO_BASES (CLOCK_TAI + 1) 42 #define VDSO_BASE_AUX 0 43 #define VDSO_HRES (BIT(CLOCK_REALTIME) | \ 44 BIT(CLOCK_MONOTONIC) | \ 45 BIT(CLOCK_BOOTTIME) | \ 46 BIT(CLOCK_TAI)) 47 #define VDSO_COARSE (BIT(CLOCK_REALTIME_COARSE) | \ 48 BIT(CLOCK_MONOTONIC_COARSE)) 49 #define VDSO_RAW (BIT(CLOCK_MONOTONIC_RAW)) 50 #define VDSO_AUX __GENMASK(CLOCK_AUX_LAST, CLOCK_AUX) 51 52 #define CS_HRES_COARSE 0 53 #define CS_RAW 1 54 #define CS_BASES (CS_RAW + 1) 55 56 /** 57 * struct vdso_timestamp - basetime per clock_id 58 * @sec: seconds 59 * @nsec: nanoseconds 60 * 61 * There is one vdso_timestamp object in vvar for each vDSO-accelerated 62 * clock_id. For high-resolution clocks, this encodes the time 63 * corresponding to vdso_time_data.cycle_last. For coarse clocks this encodes 64 * the actual time. 65 * 66 * To be noticed that for highres clocks nsec is left-shifted by 67 * vdso_time_data[x].shift. 68 */ 69 struct vdso_timestamp { 70 u64 sec; 71 u64 nsec; 72 }; 73 74 /** 75 * struct vdso_clock - vdso per clocksource datapage representation 76 * @seq: timebase sequence counter 77 * @clock_mode: clock mode 78 * @cycle_last: timebase at clocksource init 79 * @max_cycles: maximum cycles which won't overflow 64bit multiplication 80 * @mask: clocksource mask 81 * @mult: clocksource multiplier 82 * @shift: clocksource shift 83 * @basetime[clock_id]: basetime per clock_id 84 * @offset[clock_id]: time namespace offset per clock_id 85 * 86 * See also struct vdso_time_data for basic access and ordering information as 87 * struct vdso_clock is used there. 88 * 89 * @basetime is used to store the base time for the system wide time getter 90 * VVAR page. 91 * 92 * @offset is used by the special time namespace VVAR pages which are 93 * installed instead of the real VVAR page. These namespace pages must set 94 * @seq to 1 and @clock_mode to VDSO_CLOCKMODE_TIMENS to force the code into 95 * the time namespace slow path. The namespace aware functions retrieve the 96 * real system wide VVAR page, read host time and add the per clock offset. 97 * For clocks which are not affected by time namespace adjustment the 98 * offset must be zero. 99 */ 100 struct vdso_clock { 101 u32 seq; 102 103 s32 clock_mode; 104 u64 cycle_last; 105 #ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT 106 u64 max_cycles; 107 #endif 108 u64 mask; 109 u32 mult; 110 u32 shift; 111 112 union { 113 struct vdso_timestamp basetime[VDSO_BASES]; 114 struct timens_offset offset[VDSO_BASES]; 115 }; 116 }; 117 118 /** 119 * struct vdso_time_data - vdso datapage representation 120 * @arch_data: architecture specific data (optional, defaults 121 * to an empty struct) 122 * @clock_data: clocksource related data (array) 123 * @aux_clock_data: auxiliary clocksource related data (array) 124 * @tz_minuteswest: minutes west of Greenwich 125 * @tz_dsttime: type of DST correction 126 * @hrtimer_res: hrtimer resolution 127 * @__unused: unused 128 * 129 * vdso_time_data will be accessed by 64 bit and compat code at the same time 130 * so we should be careful before modifying this structure. 131 * 132 * The ordering of the struct members is optimized to have fast acces to the 133 * often required struct members which are related to CLOCK_REALTIME and 134 * CLOCK_MONOTONIC. This information is stored in the first cache lines. 135 */ 136 struct vdso_time_data { 137 struct arch_vdso_time_data arch_data; 138 139 struct vdso_clock clock_data[CS_BASES]; 140 struct vdso_clock aux_clock_data[MAX_AUX_CLOCKS]; 141 142 s32 tz_minuteswest; 143 s32 tz_dsttime; 144 u32 hrtimer_res; 145 u32 __unused; 146 } ____cacheline_aligned; 147 148 /** 149 * struct vdso_rng_data - vdso RNG state information 150 * @generation: counter representing the number of RNG reseeds 151 * @is_ready: boolean signaling whether the RNG is initialized 152 */ 153 struct vdso_rng_data { 154 u64 generation; 155 u8 is_ready; 156 }; 157 158 /* 159 * We use the hidden visibility to prevent the compiler from generating a GOT 160 * relocation. Not only is going through a GOT useless (the entry couldn't and 161 * must not be overridden by another library), it does not even work: the linker 162 * cannot generate an absolute address to the data page. 163 * 164 * With the hidden visibility, the compiler simply generates a PC-relative 165 * relocation, and this is what we need. 166 */ 167 #ifdef CONFIG_GENERIC_VDSO_DATA_STORE 168 extern struct vdso_time_data vdso_u_time_data __attribute__((visibility("hidden"))); 169 extern struct vdso_rng_data vdso_u_rng_data __attribute__((visibility("hidden"))); 170 extern struct vdso_arch_data vdso_u_arch_data __attribute__((visibility("hidden"))); 171 172 extern struct vdso_time_data *vdso_k_time_data; 173 extern struct vdso_rng_data *vdso_k_rng_data; 174 extern struct vdso_arch_data *vdso_k_arch_data; 175 176 #define VDSO_ARCH_DATA_SIZE ALIGN(sizeof(struct vdso_arch_data), PAGE_SIZE) 177 #define VDSO_ARCH_DATA_PAGES (VDSO_ARCH_DATA_SIZE >> PAGE_SHIFT) 178 179 enum vdso_pages { 180 VDSO_TIME_PAGE_OFFSET, 181 VDSO_TIMENS_PAGE_OFFSET, 182 VDSO_RNG_PAGE_OFFSET, 183 VDSO_ARCH_PAGES_START, 184 VDSO_ARCH_PAGES_END = VDSO_ARCH_PAGES_START + VDSO_ARCH_DATA_PAGES - 1, 185 VDSO_NR_PAGES 186 }; 187 188 #endif /* CONFIG_GENERIC_VDSO_DATA_STORE */ 189 190 /* 191 * The generic vDSO implementation requires that gettimeofday.h 192 * provides: 193 * - __arch_get_hw_counter(): to get the hw counter based on the 194 * clock_mode. 195 * - gettimeofday_fallback(): fallback for gettimeofday. 196 * - clock_gettime_fallback(): fallback for clock_gettime. 197 * - clock_getres_fallback(): fallback for clock_getres. 198 */ 199 #ifdef ENABLE_COMPAT_VDSO 200 #include <asm/vdso/compat_gettimeofday.h> 201 #else 202 #include <asm/vdso/gettimeofday.h> 203 #endif /* ENABLE_COMPAT_VDSO */ 204 205 #else /* !__ASSEMBLY__ */ 206 207 #ifdef CONFIG_VDSO_GETRANDOM 208 #define __vdso_u_rng_data PROVIDE(vdso_u_rng_data = vdso_u_data + 2 * PAGE_SIZE); 209 #else 210 #define __vdso_u_rng_data 211 #endif 212 213 #ifdef CONFIG_ARCH_HAS_VDSO_ARCH_DATA 214 #define __vdso_u_arch_data PROVIDE(vdso_u_arch_data = vdso_u_data + 3 * PAGE_SIZE); 215 #else 216 #define __vdso_u_arch_data 217 #endif 218 219 #define VDSO_VVAR_SYMS \ 220 PROVIDE(vdso_u_data = . - __VDSO_PAGES * PAGE_SIZE); \ 221 PROVIDE(vdso_u_time_data = vdso_u_data); \ 222 __vdso_u_rng_data \ 223 __vdso_u_arch_data \ 224 225 226 #endif /* !__ASSEMBLY__ */ 227 228 #endif /* __VDSO_DATAPAGE_H */ 229