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/types.h> 8 9 #include <uapi/linux/bits.h> 10 #include <uapi/linux/time.h> 11 12 #include <vdso/align.h> 13 #include <vdso/bits.h> 14 #include <vdso/cache.h> 15 #include <vdso/page.h> 16 #include <vdso/time.h> 17 18 #ifdef CONFIG_ARCH_HAS_VDSO_TIME_DATA 19 #include <asm/vdso/time_data.h> 20 #else 21 struct arch_vdso_time_data {}; 22 #endif 23 24 #if defined(CONFIG_ARCH_HAS_VDSO_ARCH_DATA) 25 #include <asm/vdso/arch_data.h> 26 #else 27 struct vdso_arch_data { 28 /* Needed for the generic code, never actually used at runtime */ 29 char __unused; 30 }; 31 #endif 32 33 #define VDSO_BASES (CLOCK_TAI + 1) 34 #define VDSO_BASE_AUX 0 35 #define VDSO_HRES (BIT(CLOCK_REALTIME) | \ 36 BIT(CLOCK_MONOTONIC) | \ 37 BIT(CLOCK_BOOTTIME) | \ 38 BIT(CLOCK_TAI)) 39 #define VDSO_COARSE (BIT(CLOCK_REALTIME_COARSE) | \ 40 BIT(CLOCK_MONOTONIC_COARSE)) 41 #define VDSO_RAW (BIT(CLOCK_MONOTONIC_RAW)) 42 #define VDSO_AUX __GENMASK(CLOCK_AUX_LAST, CLOCK_AUX) 43 44 #define CS_HRES_COARSE 0 45 #define CS_RAW 1 46 #define CS_BASES (CS_RAW + 1) 47 48 /** 49 * struct vdso_timestamp - basetime per clock_id 50 * @sec: seconds 51 * @nsec: nanoseconds 52 * 53 * There is one vdso_timestamp object in vvar for each vDSO-accelerated 54 * clock_id. For high-resolution clocks, this encodes the time 55 * corresponding to vdso_time_data.cycle_last. For coarse clocks this encodes 56 * the actual time. 57 * 58 * To be noticed that for highres clocks nsec is left-shifted by 59 * vdso_time_data[x].shift. 60 */ 61 struct vdso_timestamp { 62 u64 sec; 63 u64 nsec; 64 }; 65 66 /** 67 * struct vdso_clock - vdso per clocksource datapage representation 68 * @seq: timebase sequence counter 69 * @clock_mode: clock mode 70 * @cycle_last: timebase at clocksource init 71 * @max_cycles: maximum cycles which won't overflow 64bit multiplication 72 * @mask: clocksource mask 73 * @mult: clocksource multiplier 74 * @shift: clocksource shift 75 * @basetime: basetime per clock_id 76 * @offset: time namespace offset per clock_id 77 * 78 * See also struct vdso_time_data for basic access and ordering information as 79 * struct vdso_clock is used there. 80 * 81 * @basetime is used to store the base time for the system wide time getter 82 * VVAR page. 83 * 84 * @offset is used by the special time namespace VVAR pages which are 85 * installed instead of the real VVAR page. These namespace pages must set 86 * @seq to 1 and @clock_mode to VDSO_CLOCKMODE_TIMENS to force the code into 87 * the time namespace slow path. The namespace aware functions retrieve the 88 * real system wide VVAR page, read host time and add the per clock offset. 89 * For clocks which are not affected by time namespace adjustment the 90 * offset must be zero. 91 */ 92 struct vdso_clock { 93 u32 seq; 94 95 s32 clock_mode; 96 u64 cycle_last; 97 #ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT 98 u64 max_cycles; 99 #endif 100 u64 mask; 101 u32 mult; 102 u32 shift; 103 104 union { 105 struct vdso_timestamp basetime[VDSO_BASES]; 106 struct timens_offset offset[VDSO_BASES]; 107 }; 108 }; 109 110 /** 111 * struct vdso_time_data - vdso datapage representation 112 * @arch_data: architecture specific data (optional, defaults 113 * to an empty struct) 114 * @clock_data: clocksource related data (array) 115 * @aux_clock_data: auxiliary clocksource related data (array) 116 * @tz_minuteswest: minutes west of Greenwich 117 * @tz_dsttime: type of DST correction 118 * @hrtimer_res: hrtimer resolution 119 * @__unused: unused 120 * 121 * vdso_time_data will be accessed by 64 bit and compat code at the same time 122 * so we should be careful before modifying this structure. 123 * 124 * The ordering of the struct members is optimized to have fast acces to the 125 * often required struct members which are related to CLOCK_REALTIME and 126 * CLOCK_MONOTONIC. This information is stored in the first cache lines. 127 */ 128 struct vdso_time_data { 129 struct arch_vdso_time_data arch_data; 130 131 struct vdso_clock clock_data[CS_BASES]; 132 struct vdso_clock aux_clock_data[MAX_AUX_CLOCKS]; 133 134 s32 tz_minuteswest; 135 s32 tz_dsttime; 136 u32 hrtimer_res; 137 u32 __unused; 138 } ____cacheline_aligned; 139 140 /** 141 * struct vdso_rng_data - vdso RNG state information 142 * @generation: counter representing the number of RNG reseeds 143 * @is_ready: boolean signaling whether the RNG is initialized 144 */ 145 struct vdso_rng_data { 146 u64 generation; 147 u8 is_ready; 148 }; 149 150 /* 151 * We use the hidden visibility to prevent the compiler from generating a GOT 152 * relocation. Not only is going through a GOT useless (the entry couldn't and 153 * must not be overridden by another library), it does not even work: the linker 154 * cannot generate an absolute address to the data page. 155 * 156 * With the hidden visibility, the compiler simply generates a PC-relative 157 * relocation, and this is what we need. 158 */ 159 extern struct vdso_time_data vdso_u_time_data __attribute__((visibility("hidden"))); 160 extern struct vdso_rng_data vdso_u_rng_data __attribute__((visibility("hidden"))); 161 extern struct vdso_arch_data vdso_u_arch_data __attribute__((visibility("hidden"))); 162 163 extern struct vdso_time_data *vdso_k_time_data; 164 extern struct vdso_rng_data *vdso_k_rng_data; 165 extern struct vdso_arch_data *vdso_k_arch_data; 166 167 #define VDSO_ARCH_DATA_SIZE ALIGN(sizeof(struct vdso_arch_data), PAGE_SIZE) 168 #define VDSO_ARCH_DATA_PAGES (VDSO_ARCH_DATA_SIZE >> PAGE_SHIFT) 169 170 enum vdso_pages { 171 VDSO_TIME_PAGE_OFFSET, 172 VDSO_TIMENS_PAGE_OFFSET, 173 VDSO_RNG_PAGE_OFFSET, 174 VDSO_ARCH_PAGES_START, 175 VDSO_ARCH_PAGES_END = VDSO_ARCH_PAGES_START + VDSO_ARCH_DATA_PAGES - 1, 176 VDSO_NR_PAGES 177 }; 178 179 #else /* !__ASSEMBLY__ */ 180 181 #ifdef CONFIG_VDSO_GETRANDOM 182 #define __vdso_u_rng_data PROVIDE(vdso_u_rng_data = vdso_u_data + 2 * PAGE_SIZE); 183 #else 184 #define __vdso_u_rng_data 185 #endif 186 187 #ifdef CONFIG_ARCH_HAS_VDSO_ARCH_DATA 188 #define __vdso_u_arch_data PROVIDE(vdso_u_arch_data = vdso_u_data + 3 * PAGE_SIZE); 189 #else 190 #define __vdso_u_arch_data 191 #endif 192 193 #define VDSO_VVAR_SYMS \ 194 PROVIDE(vdso_u_data = . - __VDSO_PAGES * PAGE_SIZE); \ 195 PROVIDE(vdso_u_time_data = vdso_u_data); \ 196 __vdso_u_rng_data \ 197 __vdso_u_arch_data \ 198 199 200 #endif /* !__ASSEMBLY__ */ 201 202 #endif /* __VDSO_DATAPAGE_H */ 203