c742b31c03
The extract cpu time instruction (ectg) instruction allows the user process to get the current thread cputime without calling into the kernel. The code that uses the instruction needs to switch to the access registers mode to get access to the per-cpu info page that contains the two base values that are needed to calculate the current cputime from the CPU timer with the ectg instruction. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
50 lines
1.2 KiB
C
50 lines
1.2 KiB
C
#ifndef __S390_VDSO_H__
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#define __S390_VDSO_H__
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#ifdef __KERNEL__
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/* Default link addresses for the vDSOs */
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#define VDSO32_LBASE 0
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#define VDSO64_LBASE 0
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#define VDSO_VERSION_STRING LINUX_2.6.26
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#ifndef __ASSEMBLY__
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/*
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* Note about the vdso_data and vdso_per_cpu_data structures:
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*
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* NEVER USE THEM IN USERSPACE CODE DIRECTLY. The layout of the
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* structure is supposed to be known only to the function in the vdso
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* itself and may change without notice.
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*/
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struct vdso_data {
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__u64 tb_update_count; /* Timebase atomicity ctr 0x00 */
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__u64 xtime_tod_stamp; /* TOD clock for xtime 0x08 */
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__u64 xtime_clock_sec; /* Kernel time 0x10 */
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__u64 xtime_clock_nsec; /* 0x18 */
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__u64 wtom_clock_sec; /* Wall to monotonic clock 0x20 */
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__u64 wtom_clock_nsec; /* 0x28 */
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__u32 tz_minuteswest; /* Minutes west of Greenwich 0x30 */
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__u32 tz_dsttime; /* Type of dst correction 0x34 */
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__u32 ectg_available;
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};
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struct vdso_per_cpu_data {
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__u64 ectg_timer_base;
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__u64 ectg_user_time;
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};
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extern struct vdso_data *vdso_data;
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#ifdef CONFIG_64BIT
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int vdso_alloc_per_cpu(int cpu, struct _lowcore *lowcore);
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void vdso_free_per_cpu(int cpu, struct _lowcore *lowcore);
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#endif
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#endif /* __ASSEMBLY__ */
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#endif /* __KERNEL__ */
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#endif /* __S390_VDSO_H__ */
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