43 lines
1.6 KiB
Diff
43 lines
1.6 KiB
Diff
From: Anna-Maria Gleixner <anna-maria@linutronix.de>
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Date: Sun, 22 Oct 2017 23:39:43 +0200
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Subject: [PATCH 06/36] hrtimer: Ensure POSIX compliance (relative
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CLOCK_REALTIME hrtimers)
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.14/older/patches-4.14-rt1.tar.xz
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POSIX specification defines, that relative CLOCK_REALTIME timers are not
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affected by clock modifications. Those timers have to use CLOCK_MONOTONIC
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to ensure POSIX compliance.
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The introduction of the additional mode HRTIMER_MODE_PINNED broke this
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requirement for pinned timers. There is no user space visible impact
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because user space timers are not using the pinned mode, but for
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consistency reasons this needs to be fixed.
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Check whether the mode has the HRTIMER_MODE_REL bit set instead of
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comparing with HRTIMER_MODE_ABS.
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Fixes: 597d0275736d ("timers: Framework for identifying pinned timers")
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Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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kernel/time/hrtimer.c | 7 ++++++-
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1 file changed, 6 insertions(+), 1 deletion(-)
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--- a/kernel/time/hrtimer.c
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+++ b/kernel/time/hrtimer.c
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@@ -1097,7 +1097,12 @@ static void __hrtimer_init(struct hrtime
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cpu_base = raw_cpu_ptr(&hrtimer_bases);
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- if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
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+ /*
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+ * Posix magic: Relative CLOCK_REALTIME timers are not affected by
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+ * clock modifications, so they needs to become CLOCK_MONOTONIC to
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+ * ensure Posix compliance.
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+ */
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+ if (clock_id == CLOCK_REALTIME && mode & HRTIMER_MODE_REL)
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clock_id = CLOCK_MONOTONIC;
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base = hrtimer_clockid_to_base(clock_id);
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