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