/* SPDX-License-Identifier: GPL-2.0 */ #ifndef __VDSO_DATAPAGE_H #define __VDSO_DATAPAGE_H #ifndef __ASSEMBLY__ #include <linux/compiler.h> #include <uapi/linux/bits.h> #include <uapi/linux/time.h> #include <uapi/linux/types.h> #include <uapi/asm-generic/errno-base.h> #include <vdso/align.h> #include <vdso/bits.h> #include <vdso/cache.h> #include <vdso/clocksource.h> #include <vdso/ktime.h> #include <vdso/limits.h> #include <vdso/math64.h> #include <vdso/page.h> #include <vdso/processor.h> #include <vdso/time.h> #include <vdso/time32.h> #include <vdso/time64.h> #ifdef CONFIG_ARCH_HAS_VDSO_TIME_DATA #include <asm/vdso/time_data.h> #else struct arch_vdso_time_data {}; #endif #if defined(CONFIG_ARCH_HAS_VDSO_ARCH_DATA) #include <asm/vdso/arch_data.h> #else struct vdso_arch_data { /* Needed for the generic code, never actually used at runtime */ char __unused; }; #endif #define VDSO_BASES (CLOCK_TAI + 1) #define VDSO_BASE_AUX 0 #define VDSO_HRES (BIT(CLOCK_REALTIME) | \ BIT(CLOCK_MONOTONIC) | \ BIT(CLOCK_BOOTTIME) | \ BIT(CLOCK_TAI)) #define VDSO_COARSE (BIT(CLOCK_REALTIME_COARSE) | \ BIT(CLOCK_MONOTONIC_COARSE)) #define VDSO_RAW (BIT(CLOCK_MONOTONIC_RAW)) #define VDSO_AUX __GENMASK(CLOCK_AUX_LAST, CLOCK_AUX) #define CS_HRES_COARSE 0 #define CS_RAW 1 #define CS_BASES (CS_RAW + 1) /** * struct vdso_timestamp - basetime per clock_id * @sec: seconds * @nsec: nanoseconds * * There is one vdso_timestamp object in vvar for each vDSO-accelerated * clock_id. For high-resolution clocks, this encodes the time * corresponding to vdso_time_data.cycle_last. For coarse clocks this encodes * the actual time. * * To be noticed that for highres clocks nsec is left-shifted by * vdso_time_data[x].shift. */ struct vdso_timestamp { u64 sec; u64 nsec; }; /** * struct vdso_clock - vdso per clocksource datapage representation * @seq: timebase sequence counter * @clock_mode: clock mode * @cycle_last: timebase at clocksource init * @max_cycles: maximum cycles which won't overflow 64bit multiplication * @mask: clocksource mask * @mult: clocksource multiplier * @shift: clocksource shift * @basetime[clock_id]: basetime per clock_id * @offset[clock_id]: time namespace offset per clock_id * * See also struct vdso_time_data for basic access and ordering information as * struct vdso_clock is used there. * * @basetime is used to store the base time for the system wide time getter * VVAR page. * * @offset is used by the special time namespace VVAR pages which are * installed instead of the real VVAR page. These namespace pages must set * @seq to 1 and @clock_mode to VDSO_CLOCKMODE_TIMENS to force the code into * the time namespace slow path. The namespace aware functions retrieve the * real system wide VVAR page, read host time and add the per clock offset. * For clocks which are not affected by time namespace adjustment the * offset must be zero. */ struct vdso_clock { u32 seq; s32 clock_mode; u64 cycle_last; #ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT u64 max_cycles; #endif u64 mask; u32 mult; u32 shift; union { struct vdso_timestamp basetime[VDSO_BASES]; struct timens_offset offset[VDSO_BASES]; }; }; /** * struct vdso_time_data - vdso datapage representation * @arch_data: architecture specific data (optional, defaults * to an empty struct) * @clock_data: clocksource related data (array) * @aux_clock_data: auxiliary clocksource related data (array) * @tz_minuteswest: minutes west of Greenwich * @tz_dsttime: type of DST correction * @hrtimer_res: hrtimer resolution * @__unused: unused * * vdso_time_data will be accessed by 64 bit and compat code at the same time * so we should be careful before modifying this structure. * * The ordering of the struct members is optimized to have fast acces to the * often required struct members which are related to CLOCK_REALTIME and * CLOCK_MONOTONIC. This information is stored in the first cache lines. */ struct vdso_time_data { struct arch_vdso_time_data arch_data; struct vdso_clock clock_data[CS_BASES]; struct vdso_clock aux_clock_data[MAX_AUX_CLOCKS]; s32 tz_minuteswest; s32 tz_dsttime; u32 hrtimer_res; u32 __unused; } ____cacheline_aligned; /** * struct vdso_rng_data - vdso RNG state information * @generation: counter representing the number of RNG reseeds * @is_ready: boolean signaling whether the RNG is initialized */ struct vdso_rng_data { u64 generation; u8 is_ready; }; /* * We use the hidden visibility to prevent the compiler from generating a GOT * relocation. Not only is going through a GOT useless (the entry couldn't and * must not be overridden by another library), it does not even work: the linker * cannot generate an absolute address to the data page. * * With the hidden visibility, the compiler simply generates a PC-relative * relocation, and this is what we need. */ extern struct vdso_time_data vdso_u_time_data __attribute__((visibility("hidden"))); extern struct vdso_rng_data vdso_u_rng_data __attribute__((visibility("hidden"))); extern struct vdso_arch_data vdso_u_arch_data __attribute__((visibility("hidden"))); extern struct vdso_time_data *vdso_k_time_data; extern struct vdso_rng_data *vdso_k_rng_data; extern struct vdso_arch_data *vdso_k_arch_data; #define VDSO_ARCH_DATA_SIZE ALIGN(sizeof(struct vdso_arch_data), PAGE_SIZE) #define VDSO_ARCH_DATA_PAGES (VDSO_ARCH_DATA_SIZE >> PAGE_SHIFT) enum vdso_pages { VDSO_TIME_PAGE_OFFSET, VDSO_TIMENS_PAGE_OFFSET, VDSO_RNG_PAGE_OFFSET, VDSO_ARCH_PAGES_START, VDSO_ARCH_PAGES_END = VDSO_ARCH_PAGES_START + VDSO_ARCH_DATA_PAGES - 1, VDSO_NR_PAGES }; /* * The generic vDSO implementation requires that gettimeofday.h * provides: * - __arch_get_hw_counter(): to get the hw counter based on the * clock_mode. * - gettimeofday_fallback(): fallback for gettimeofday. * - clock_gettime_fallback(): fallback for clock_gettime. * - clock_getres_fallback(): fallback for clock_getres. */ #include <asm/vdso/gettimeofday.h> #else /* !__ASSEMBLY__ */ #ifdef CONFIG_VDSO_GETRANDOM #define __vdso_u_rng_data PROVIDE(vdso_u_rng_data = vdso_u_data + 2 * PAGE_SIZE); #else #define __vdso_u_rng_data #endif #ifdef CONFIG_ARCH_HAS_VDSO_ARCH_DATA #define __vdso_u_arch_data PROVIDE(vdso_u_arch_data = vdso_u_data + 3 * PAGE_SIZE); #else #define __vdso_u_arch_data #endif #define VDSO_VVAR_SYMS \ PROVIDE(vdso_u_data = . - __VDSO_PAGES * PAGE_SIZE); \ PROVIDE(vdso_u_time_data = vdso_u_data); \ __vdso_u_rng_data \ __vdso_u_arch_data \ #endif /* !__ASSEMBLY__ */ #endif /* __VDSO_DATAPAGE_H */
