linux/arch/s390/include/asm/vdso.h
Vincenzo Frascino 478237a595 s390/vdso: fix vDSO clock_getres()
clock_getres in the vDSO library has to preserve the same behaviour
of posix_get_hrtimer_res().

In particular, posix_get_hrtimer_res() does:
    sec = 0;
    ns = hrtimer_resolution;
and hrtimer_resolution depends on the enablement of the high
resolution timers that can happen either at compile or at run time.

Fix the s390 vdso implementation of clock_getres keeping a copy of
hrtimer_resolution in vdso data and using that directly.

Link: https://lkml.kernel.org/r/20200324121027.21665-1-vincenzo.frascino@arm.com
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
[heiko.carstens@de.ibm.com: use llgf for proper zero extension]
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2020-06-16 13:44:05 +02:00

67 lines
2.0 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __S390_VDSO_H__
#define __S390_VDSO_H__
/* Default link addresses for the vDSOs */
#define VDSO32_LBASE 0
#define VDSO64_LBASE 0
#define VDSO_VERSION_STRING LINUX_2.6.29
#ifndef __ASSEMBLY__
/*
* Note about the vdso_data and vdso_per_cpu_data structures:
*
* 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 tb_update_count; /* Timebase atomicity ctr 0x00 */
__u64 xtime_tod_stamp; /* TOD clock for xtime 0x08 */
__u64 xtime_clock_sec; /* Kernel time 0x10 */
__u64 xtime_clock_nsec; /* 0x18 */
__u64 xtime_coarse_sec; /* Coarse kernel time 0x20 */
__u64 xtime_coarse_nsec; /* 0x28 */
__u64 wtom_clock_sec; /* Wall to monotonic clock 0x30 */
__u64 wtom_clock_nsec; /* 0x38 */
__u64 wtom_coarse_sec; /* Coarse wall to monotonic 0x40 */
__u64 wtom_coarse_nsec; /* 0x48 */
__u32 tz_minuteswest; /* Minutes west of Greenwich 0x50 */
__u32 tz_dsttime; /* Type of dst correction 0x54 */
__u32 ectg_available; /* ECTG instruction present 0x58 */
__u32 tk_mult; /* Mult. used for xtime_nsec 0x5c */
__u32 tk_shift; /* Shift used for xtime_nsec 0x60 */
__u32 ts_dir; /* TOD steering direction 0x64 */
__u64 ts_end; /* TOD steering end 0x68 */
__u32 hrtimer_res; /* hrtimer resolution 0x70 */
};
struct vdso_per_cpu_data {
__u64 ectg_timer_base;
__u64 ectg_user_time;
/*
* Note: node_id and cpu_nr must be at adjacent memory locations.
* VDSO userspace must read both values with a single instruction.
*/
union {
__u64 getcpu_val;
struct {
__u32 node_id;
__u32 cpu_nr;
};
};
};
extern struct vdso_data *vdso_data;
extern struct vdso_data boot_vdso_data;
void vdso_alloc_boot_cpu(struct lowcore *lowcore);
int vdso_alloc_per_cpu(struct lowcore *lowcore);
void vdso_free_per_cpu(struct lowcore *lowcore);
#endif /* __ASSEMBLY__ */
#endif /* __S390_VDSO_H__ */