linux/arch/arm/include/asm/vdso_datapage.h
Nathan Lynch 1713ce7c43 ARM: 8329/1: miscellaneous vdso infrastructure, preparation
Define the layout of the data structure shared between kernel and
userspace.

Track the vdso address in the mm_context; needed for communicating
AT_SYSINFO_EHDR to the ELF loader.

Add declarations for arm_install_vdso; implementation is in a
following patch.

Define AT_SYSINFO_EHDR, and, if CONFIG_VDSO=y, report the vdso shared
object address via the ELF auxiliary vector.

Note - this adds the AT_SYSINFO_EHDR in a new user-visible header
asm/auxvec.h; this is consistent with other architectures.

Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-03-27 22:20:45 +00:00

61 lines
1.7 KiB
C

/*
* Adapted from arm64 version.
*
* Copyright (C) 2012 ARM Limited
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 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. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ASM_VDSO_DATAPAGE_H
#define __ASM_VDSO_DATAPAGE_H
#ifdef __KERNEL__
#ifndef __ASSEMBLY__
#include <asm/page.h>
/* Try to be cache-friendly on systems that don't implement the
* generic timer: fit the unconditionally updated fields in the first
* 32 bytes.
*/
struct vdso_data {
u32 seq_count; /* sequence count - odd during updates */
u16 tk_is_cntvct; /* fall back to syscall if false */
u16 cs_shift; /* clocksource shift */
u32 xtime_coarse_sec; /* coarse time */
u32 xtime_coarse_nsec;
u32 wtm_clock_sec; /* wall to monotonic offset */
u32 wtm_clock_nsec;
u32 xtime_clock_sec; /* CLOCK_REALTIME - seconds */
u32 cs_mult; /* clocksource multiplier */
u64 cs_cycle_last; /* last cycle value */
u64 cs_mask; /* clocksource mask */
u64 xtime_clock_snsec; /* CLOCK_REALTIME sub-ns base */
u32 tz_minuteswest; /* timezone info for gettimeofday(2) */
u32 tz_dsttime;
};
union vdso_data_store {
struct vdso_data data;
u8 page[PAGE_SIZE];
};
#endif /* !__ASSEMBLY__ */
#endif /* __KERNEL__ */
#endif /* __ASM_VDSO_DATAPAGE_H */