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597bc5c00b
Currently the clock_gettime implementation in the VDSO produces a result with microsecond resolution for the cases that are handled without a system call, i.e. CLOCK_REALTIME and CLOCK_MONOTONIC. The nanoseconds field of the result is obtained by computing a microseconds value and multiplying by 1000. This changes the code in the VDSO to do the computation for clock_gettime with nanosecond resolution. That means that the resolution of the result will ultimately depend on the timebase frequency. Because the timestamp in the VDSO datapage (stamp_xsec, the real time corresponding to the timebase count in tb_orig_stamp) is in units of 2^-20 seconds, it doesn't have sufficient resolution for computing a result with nanosecond resolution. Therefore this adds a copy of xtime to the VDSO datapage and updates it in update_gtod() along with the other time-related fields. Signed-off-by: Paul Mackerras <paulus@samba.org>
125 lines
4.2 KiB
C
125 lines
4.2 KiB
C
#ifndef _VDSO_DATAPAGE_H
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#define _VDSO_DATAPAGE_H
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#ifdef __KERNEL__
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/*
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* Copyright (C) 2002 Peter Bergner <bergner@vnet.ibm.com>, IBM
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* Copyright (C) 2005 Benjamin Herrenschmidy <benh@kernel.crashing.org>,
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* IBM Corp.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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/*
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* Note about this structure:
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*
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* This structure was historically called systemcfg and exposed to
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* userland via /proc/ppc64/systemcfg. Unfortunately, this became an
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* ABI issue as some proprietary software started relying on being able
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* to mmap() it, thus we have to keep the base layout at least for a
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* few kernel versions.
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*
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* However, since ppc32 doesn't suffer from this backward handicap,
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* a simpler version of the data structure is used there with only the
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* fields actually used by the vDSO.
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*
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*/
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/*
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* If the major version changes we are incompatible.
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* Minor version changes are a hint.
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*/
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#define SYSTEMCFG_MAJOR 1
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#define SYSTEMCFG_MINOR 1
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#ifndef __ASSEMBLY__
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#include <linux/unistd.h>
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#include <linux/time.h>
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#define SYSCALL_MAP_SIZE ((__NR_syscalls + 31) / 32)
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/*
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* So here is the ppc64 backward compatible version
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*/
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#ifdef CONFIG_PPC64
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struct vdso_data {
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__u8 eye_catcher[16]; /* Eyecatcher: SYSTEMCFG:PPC64 0x00 */
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struct { /* Systemcfg version numbers */
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__u32 major; /* Major number 0x10 */
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__u32 minor; /* Minor number 0x14 */
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} version;
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/* Note about the platform flags: it now only contains the lpar
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* bit. The actual platform number is dead and burried
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*/
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__u32 platform; /* Platform flags 0x18 */
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__u32 processor; /* Processor type 0x1C */
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__u64 processorCount; /* # of physical processors 0x20 */
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__u64 physicalMemorySize; /* Size of real memory(B) 0x28 */
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__u64 tb_orig_stamp; /* Timebase at boot 0x30 */
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__u64 tb_ticks_per_sec; /* Timebase tics / sec 0x38 */
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__u64 tb_to_xs; /* Inverse of TB to 2^20 0x40 */
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__u64 stamp_xsec; /* 0x48 */
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__u64 tb_update_count; /* Timebase atomicity ctr 0x50 */
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__u32 tz_minuteswest; /* Minutes west of Greenwich 0x58 */
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__u32 tz_dsttime; /* Type of dst correction 0x5C */
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__u32 dcache_size; /* L1 d-cache size 0x60 */
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__u32 dcache_line_size; /* L1 d-cache line size 0x64 */
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__u32 icache_size; /* L1 i-cache size 0x68 */
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__u32 icache_line_size; /* L1 i-cache line size 0x6C */
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/* those additional ones don't have to be located anywhere
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* special as they were not part of the original systemcfg
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*/
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__u32 dcache_block_size; /* L1 d-cache block size */
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__u32 icache_block_size; /* L1 i-cache block size */
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__u32 dcache_log_block_size; /* L1 d-cache log block size */
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__u32 icache_log_block_size; /* L1 i-cache log block size */
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__s32 wtom_clock_sec; /* Wall to monotonic clock */
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__s32 wtom_clock_nsec;
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struct timespec stamp_xtime; /* xtime as at tb_orig_stamp */
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__u32 syscall_map_64[SYSCALL_MAP_SIZE]; /* map of syscalls */
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__u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */
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};
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#else /* CONFIG_PPC64 */
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/*
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* And here is the simpler 32 bits version
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*/
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struct vdso_data {
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__u64 tb_orig_stamp; /* Timebase at boot 0x30 */
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__u64 tb_ticks_per_sec; /* Timebase tics / sec 0x38 */
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__u64 tb_to_xs; /* Inverse of TB to 2^20 0x40 */
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__u64 stamp_xsec; /* 0x48 */
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__u32 tb_update_count; /* Timebase atomicity ctr 0x50 */
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__u32 tz_minuteswest; /* Minutes west of Greenwich 0x58 */
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__u32 tz_dsttime; /* Type of dst correction 0x5C */
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__s32 wtom_clock_sec; /* Wall to monotonic clock */
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__s32 wtom_clock_nsec;
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struct timespec stamp_xtime; /* xtime as at tb_orig_stamp */
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__u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */
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__u32 dcache_block_size; /* L1 d-cache block size */
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__u32 icache_block_size; /* L1 i-cache block size */
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__u32 dcache_log_block_size; /* L1 d-cache log block size */
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__u32 icache_log_block_size; /* L1 i-cache log block size */
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};
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#endif /* CONFIG_PPC64 */
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#ifdef __KERNEL__
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extern struct vdso_data *vdso_data;
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#endif
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#endif /* __ASSEMBLY__ */
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#endif /* __KERNEL__ */
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#endif /* _SYSTEMCFG_H */
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