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19d0070a27
Architectures can have the requirement to add additional architecture specific data to the VDSO data page which needs to be updated independent of the timekeeper updates. To protect these updates vs. concurrent readers and a conflicting update through timekeeping, provide helper functions to make such updates safe. vdso_update_begin() takes the timekeeper_lock to protect against a potential update from timekeeper code and increments the VDSO sequence count to signal data inconsistency to concurrent readers. vdso_update_end() makes the sequence count even again to signal data consistency and drops the timekeeper lock. [ Sven: Add interrupt disable handling to the functions ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20200804150124.41692-3-svens@linux.ibm.com
15 lines
288 B
C
15 lines
288 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __VDSO_VSYSCALL_H
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#define __VDSO_VSYSCALL_H
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#ifndef __ASSEMBLY__
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#include <asm/vdso/vsyscall.h>
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unsigned long vdso_update_begin(void);
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void vdso_update_end(unsigned long flags);
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#endif /* !__ASSEMBLY__ */
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#endif /* __VDSO_VSYSCALL_H */
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