linux-kernel - [tip:timers/2038] timekeeping: Add ktime_get_coarse_with

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <tip-b9ff604cff1135cc576cf952d394ed9401aa234b@git.kernel.org>
Date:   Sat, 19 May 2018 05:02:15 -0700
From:   tip-bot for Arnd Bergmann <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     john.stultz@...aro.org, mingo@...nel.org, sboyd@...nel.org,
        arnd@...db.de, hpa@...or.com, tglx@...utronix.de,
        linux-kernel@...r.kernel.org
Subject: [tip:timers/2038] timekeeping: Add ktime_get_coarse_with_offset

Commit-ID:  b9ff604cff1135cc576cf952d394ed9401aa234b
Gitweb:     https://git.kernel.org/tip/b9ff604cff1135cc576cf952d394ed9401aa234b
Author:     Arnd Bergmann <arnd@...db.de>
AuthorDate: Fri, 27 Apr 2018 15:40:15 +0200
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Sat, 19 May 2018 13:57:32 +0200

timekeeping: Add ktime_get_coarse_with_offset

I have run into a couple of drivers using current_kernel_time()
suffering from the y2038 problem, and they could be converted
to using ktime_t, but don't have interfaces that skip the nanosecond
calculation at the moment.

This introduces ktime_get_coarse_with_offset() as a simpler
variant of ktime_get_with_offset(), and adds wrappers for the
three time domains we support with the existing function.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Stephen Boyd <sboyd@...nel.org>
Cc: y2038@...ts.linaro.org
Cc: John Stultz <john.stultz@...aro.org>
Link: https://lkml.kernel.org/r/20180427134016.2525989-5-arnd@arndb.de

---
 include/linux/timekeeping.h | 16 ++++++++++++++++
 kernel/time/timekeeping.c   | 19 +++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 3ef9791d7d75..42f71f4b658a 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -51,6 +51,7 @@ enum tk_offsets {
 
 extern ktime_t ktime_get(void);
 extern ktime_t ktime_get_with_offset(enum tk_offsets offs);
+extern ktime_t ktime_get_coarse_with_offset(enum tk_offsets offs);
 extern ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs);
 extern ktime_t ktime_get_raw(void);
 extern u32 ktime_get_resolution_ns(void);
@@ -63,6 +64,11 @@ static inline ktime_t ktime_get_real(void)
 	return ktime_get_with_offset(TK_OFFS_REAL);
 }
 
+static inline ktime_t ktime_get_coarse_real(void)
+{
+	return ktime_get_coarse_with_offset(TK_OFFS_REAL);
+}
+
 /**
  * ktime_get_boottime - Returns monotonic time since boot in ktime_t format
  *
@@ -74,6 +80,11 @@ static inline ktime_t ktime_get_boottime(void)
 	return ktime_get_with_offset(TK_OFFS_BOOT);
 }
 
+static inline ktime_t ktime_get_coarse_boottime(void)
+{
+	return ktime_get_coarse_with_offset(TK_OFFS_BOOT);
+}
+
 /**
  * ktime_get_clocktai - Returns the TAI time of day in ktime_t format
  */
@@ -82,6 +93,11 @@ static inline ktime_t ktime_get_clocktai(void)
 	return ktime_get_with_offset(TK_OFFS_TAI);
 }
 
+static inline ktime_t ktime_get_coarse_clocktai(void)
+{
+	return ktime_get_coarse_with_offset(TK_OFFS_TAI);
+}
+
 /**
  * ktime_mono_to_real - Convert monotonic time to clock realtime
  */
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index ed9b74ec9c0b..4786df904c22 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -795,6 +795,25 @@ ktime_t ktime_get_with_offset(enum tk_offsets offs)
 }
 EXPORT_SYMBOL_GPL(ktime_get_with_offset);
 
+ktime_t ktime_get_coarse_with_offset(enum tk_offsets offs)
+{
+	struct timekeeper *tk = &tk_core.timekeeper;
+	unsigned int seq;
+	ktime_t base, *offset = offsets[offs];
+
+	WARN_ON(timekeeping_suspended);
+
+	do {
+		seq = read_seqcount_begin(&tk_core.seq);
+		base = ktime_add(tk->tkr_mono.base, *offset);
+
+	} while (read_seqcount_retry(&tk_core.seq, seq));
+
+	return base;
+
+}
+EXPORT_SYMBOL_GPL(ktime_get_coarse_with_offset);
+
 /**
  * ktime_mono_to_any() - convert mononotic time to any other time
  * @tmono:	time to convert.