linux-kernel - [PATCH 10/19] vdso/gettimeofday: Prepare do_coarse_timens() for introduction of struct vdso

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Message-Id: <20250303-vdso-clock-v1-10-c1b5c69a166f@linutronix.de>
Date: Mon, 03 Mar 2025 12:11:12 +0100
From: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
To: Andy Lutomirski <luto@...nel.org>, Thomas Gleixner <tglx@...utronix.de>, 
 Vincenzo Frascino <vincenzo.frascino@....com>, 
 Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>, 
 Anna-Maria Behnsen <anna-maria@...utronix.de>, 
 Frederic Weisbecker <frederic@...nel.org>, Ingo Molnar <mingo@...hat.com>, 
 Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>, 
 x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>, 
 Madhavan Srinivasan <maddy@...ux.ibm.com>, 
 Michael Ellerman <mpe@...erman.id.au>, Nicholas Piggin <npiggin@...il.com>, 
 Christophe Leroy <christophe.leroy@...roup.eu>, 
 Naveen N Rao <naveen@...nel.org>, Heiko Carstens <hca@...ux.ibm.com>, 
 Vasily Gorbik <gor@...ux.ibm.com>, 
 Alexander Gordeev <agordeev@...ux.ibm.com>, 
 Christian Borntraeger <borntraeger@...ux.ibm.com>, 
 Sven Schnelle <svens@...ux.ibm.com>, Arnd Bergmann <arnd@...db.de>
Cc: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
 linuxppc-dev@...ts.ozlabs.org, linux-s390@...r.kernel.org, 
 linux-arch@...r.kernel.org, Nam Cao <namcao@...utronix.de>, 
 Thomas Weißschuh <thomas.weissschuh@...utronix.de>
Subject: [PATCH 10/19] vdso/gettimeofday: Prepare do_coarse_timens() for
 introduction of struct vdso_clock

From: Anna-Maria Behnsen <anna-maria@...utronix.de>

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 array of it. At the moment, vdso_clock
is simply a define which maps vdso_clock to vdso_time_data.

Prepare for the rework of these structures by adding struct vdso_clock
pointer argument to do_coarse_timens(), and replace the struct
vdso_time_data pointer with the new pointer arugment whenever applicable.

No functional change.

Signed-off-by: Anna-Maria Behnsen <anna-maria@...utronix.de>
Signed-off-by: Nam Cao <namcao@...utronix.de>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
---
 lib/vdso/gettimeofday.c | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c
index 36ef7de097e6137832605928a155a0ff78123fb4..03fa0393645ac0f5ee465ddc19d84b330913da65 100644
--- a/lib/vdso/gettimeofday.c
+++ b/lib/vdso/gettimeofday.c
@@ -193,21 +193,25 @@ int do_hres(const struct vdso_time_data *vd, const struct vdso_clock *vc,
 }

 #ifdef CONFIG_TIME_NS
-static __always_inline int do_coarse_timens(const struct vdso_time_data *vdns, clockid_t clk,
-					    struct __kernel_timespec *ts)
+static __always_inline
+int do_coarse_timens(const struct vdso_time_data *vdns, const struct vdso_clock *vcns,
+		     clockid_t clk, struct __kernel_timespec *ts)
 {
 	const struct vdso_time_data *vd = __arch_get_vdso_u_timens_data(vdns);
-	const struct vdso_timestamp *vdso_ts = &vd->basetime[clk];
-	const struct timens_offset *offs = &vdns->offset[clk];
+	const struct timens_offset *offs = &vcns->offset[clk];
+	const struct vdso_timestamp *vdso_ts;
+	const struct vdso_clock *vc = vd;
 	u64 nsec;
 	s64 sec;
 	s32 seq;

+	vdso_ts = &vc->basetime[clk];
+
 	do {
-		seq = vdso_read_begin(vd);
+		seq = vdso_read_begin(vc);
 		sec = vdso_ts->sec;
 		nsec = vdso_ts->nsec;
-	} while (unlikely(vdso_read_retry(vd, seq)));
+	} while (unlikely(vdso_read_retry(vc, seq)));

 	/* Add the namespace offset */
 	sec += offs->sec;
@@ -222,8 +226,9 @@ static __always_inline int do_coarse_timens(const struct vdso_time_data *vdns, c
 	return 0;
 }
 #else
-static __always_inline int do_coarse_timens(const struct vdso_time_data *vdns, clockid_t clk,
-					    struct __kernel_timespec *ts)
+static __always_inline
+int do_coarse_timens(const struct vdso_time_data *vdns, const struct vdso_clock *vcns,
+		     clockid_t clk, struct __kernel_timespec *ts)
 {
 	return -1;
 }
@@ -244,7 +249,7 @@ int do_coarse(const struct vdso_time_data *vd, const struct vdso_clock *vc,
 		while ((seq = READ_ONCE(vc->seq)) & 1) {
 			if (IS_ENABLED(CONFIG_TIME_NS) &&
 			    vc->clock_mode == VDSO_CLOCKMODE_TIMENS)
-				return do_coarse_timens(vc, clk, ts);
+				return do_coarse_timens(vd, vc, clk, ts);
 			cpu_relax();
 		}
 		smp_rmb();

-- 
2.48.1