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To support multiple PTP clocks, the VDSO data structure needs to be reworked. All clock specific data will end up in struct vdso_clock and in struct vdso_time_data there will be an array of VDSO clocks. Now that all preparatory changes are in place: Split the clock related struct members into a separate struct vdso_clock. Make sure all users are aware, that vdso_time_data is no longer initialized as an array and vdso_clock is now the array inside vdso_data. Remove the vdso_clock define, which mapped it to vdso_time_data for the transition. Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de> Signed-off-by: Nam Cao <namcao@linutronix.de> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20250303-vdso-clock-v1-19-c1b5c69a166f@linutronix.de
61 lines
1.4 KiB
C
61 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __VDSO_HELPERS_H
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#define __VDSO_HELPERS_H
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#ifndef __ASSEMBLY__
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#include <asm/barrier.h>
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#include <vdso/datapage.h>
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static __always_inline u32 vdso_read_begin(const struct vdso_clock *vc)
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{
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u32 seq;
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while (unlikely((seq = READ_ONCE(vc->seq)) & 1))
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cpu_relax();
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smp_rmb();
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return seq;
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}
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static __always_inline u32 vdso_read_retry(const struct vdso_clock *vc,
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u32 start)
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{
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u32 seq;
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smp_rmb();
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seq = READ_ONCE(vc->seq);
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return seq != start;
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}
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static __always_inline void vdso_write_begin(struct vdso_time_data *vd)
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{
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struct vdso_clock *vc = vd->clock_data;
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/*
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* WRITE_ONCE() is required otherwise the compiler can validly tear
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* updates to vd[x].seq and it is possible that the value seen by the
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* reader is inconsistent.
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*/
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WRITE_ONCE(vc[CS_HRES_COARSE].seq, vc[CS_HRES_COARSE].seq + 1);
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WRITE_ONCE(vc[CS_RAW].seq, vc[CS_RAW].seq + 1);
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smp_wmb();
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}
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static __always_inline void vdso_write_end(struct vdso_time_data *vd)
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{
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struct vdso_clock *vc = vd->clock_data;
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smp_wmb();
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/*
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* WRITE_ONCE() is required otherwise the compiler can validly tear
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* updates to vd[x].seq and it is possible that the value seen by the
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* reader is inconsistent.
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*/
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WRITE_ONCE(vc[CS_HRES_COARSE].seq, vc[CS_HRES_COARSE].seq + 1);
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WRITE_ONCE(vc[CS_RAW].seq, vc[CS_RAW].seq + 1);
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}
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#endif /* !__ASSEMBLY__ */
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#endif /* __VDSO_HELPERS_H */
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