[tip: timers/vdso] vdso/datapage: Define vdso_clock to prepare for multiple PTP clocks

["tip-bot2 for Anna-Maria Behnsen" <tip-bot2@linutronix.de>]

The following commit has been merged into the timers/vdso branch of tip:

Commit-ID:     a05f14de04e989f0bc32cea128243090e5e5d54b
Gitweb:        https://git.kernel.org/tip/a05f14de04e989f0bc32cea128243090e5e5d54b
Author:        Anna-Maria Behnsen <anna-maria@linutronix.de>
AuthorDate:    Mon, 03 Mar 2025 12:11:06 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Sat, 08 Mar 2025 14:37:40 +01:00

vdso/datapage: Define vdso_clock to prepare for multiple PTP clocks

Multiple PTP clocks, which are independent of timekeeping, are required for
systems, which utilize PTP for synchronizing e.g. automation systems
independent of clock TAI.

PTP clocks are slow to access, but applications require fast access to the
relevant time similar to the regular timekeeping relevant clocks.

To prepare for that the VDSO data representation must be reworked. For
transition to the new structure of the vdso, add a define which maps
vdso_clock to vdso_data. This will be removed when all users are updated
step by step.

No functional change.

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-v1-4-c1b5c69a166f@linutronix.de

---
 include/vdso/datapage.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h
index dfd98f9..1df22e8 100644
--- a/include/vdso/datapage.h
+++ b/include/vdso/datapage.h
@@ -129,6 +129,8 @@ struct vdso_time_data {
 	struct arch_vdso_time_data arch_data;
 } ____cacheline_aligned;
 
+#define vdso_clock vdso_time_data
+
 /**
  * struct vdso_rng_data - vdso RNG state information
  * @generation:	counter representing the number of RNG reseeds