linux_dsm_epyc7002/arch/tile/include/asm/vdso.h
Chris Metcalf 4a556f4f56 tile: implement gettimeofday() via vDSO
This change creates the framework for vDSO calls, makes the existing
rt_sigreturn() mechanism use it, and adds a fast gettimeofday().
Now that we need to expose the vDSO address to userspace, we add
AT_SYSINFO_EHDR to the set of aux entries provided to userspace.
(You can disable any extra vDSO support by booting with vdso=0,
but the rt_sigreturn vDSO page will still be provided.)

Note that glibc has supported the tile vDSO since release 2.17.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2013-08-13 16:26:21 -04:00

50 lines
1.8 KiB
C

/*
* Copyright 2012 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#ifndef __TILE_VDSO_H__
#define __TILE_VDSO_H__
#include <linux/types.h>
/*
* Note about the vdso_data structure:
*
* NEVER USE THEM IN USERSPACE CODE DIRECTLY. The layout of the
* structure is supposed to be known only to the function in the vdso
* itself and may change without notice.
*/
struct vdso_data {
__u64 tz_update_count; /* Timezone atomicity ctr */
__u64 tb_update_count; /* Timebase atomicity ctr */
__u64 xtime_tod_stamp; /* TOD clock for xtime */
__u64 xtime_clock_sec; /* Kernel time second */
__u64 xtime_clock_nsec; /* Kernel time nanosecond */
__u64 wtom_clock_sec; /* Wall to monotonic clock second */
__u64 wtom_clock_nsec; /* Wall to monotonic clock nanosecond */
__u32 mult; /* Cycle to nanosecond multiplier */
__u32 shift; /* Cycle to nanosecond divisor (power of two) */
__u32 tz_minuteswest; /* Minutes west of Greenwich */
__u32 tz_dsttime; /* Type of dst correction */
};
extern struct vdso_data *vdso_data;
/* __vdso_rt_sigreturn is defined with the addresses in the vdso page. */
extern void __vdso_rt_sigreturn(void);
extern int setup_vdso_pages(void);
#endif /* __TILE_VDSO_H__ */