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authorMichael Kelley <mikelley@microsoft.com>2021-03-02 13:38:20 -0800
committerWei Liu <wei.liu@kernel.org>2021-03-08 17:33:00 +0000
commiteb3e1d370b4c57be1acbb9de51a7deaa036eff4b (patch)
treed476d56fb76984e4a0eaa2d4efe0a4990133c85f /drivers/clocksource
parente4ab4658f1cff14c82202132f7af2cb5c2741469 (diff)
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clocksource/drivers/hyper-v: Handle sched_clock differences inline
While the Hyper-V Reference TSC code is architecture neutral, the pv_ops.time.sched_clock() function is implemented for x86/x64, but not for ARM64. Current code calls a utility function under arch/x86 (and coming, under arch/arm64) to handle the difference. Change this approach to handle the difference inline based on whether GENERIC_SCHED_CLOCK is present. The new approach removes code under arch/* since the difference is tied more to the specifics of the Linux implementation than to the architecture. No functional change. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: https://lore.kernel.org/r/1614721102-2241-9-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
Diffstat (limited to 'drivers/clocksource')
-rw-r--r--drivers/clocksource/hyperv_timer.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index 06984fa11936..10eb5c645141 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -423,6 +423,30 @@ static struct clocksource hyperv_cs_msr = {
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
+/*
+ * Reference to pv_ops must be inline so objtool
+ * detection of noinstr violations can work correctly.
+ */
+#ifdef CONFIG_GENERIC_SCHED_CLOCK
+static __always_inline void hv_setup_sched_clock(void *sched_clock)
+{
+ /*
+ * We're on an architecture with generic sched clock (not x86/x64).
+ * The Hyper-V sched clock read function returns nanoseconds, not
+ * the normal 100ns units of the Hyper-V synthetic clock.
+ */
+ sched_clock_register(sched_clock, 64, NSEC_PER_SEC);
+}
+#elif defined CONFIG_PARAVIRT
+static __always_inline void hv_setup_sched_clock(void *sched_clock)
+{
+ /* We're on x86/x64 *and* using PV ops */
+ pv_ops.time.sched_clock = sched_clock;
+}
+#else /* !CONFIG_GENERIC_SCHED_CLOCK && !CONFIG_PARAVIRT */
+static __always_inline void hv_setup_sched_clock(void *sched_clock) {}
+#endif /* CONFIG_GENERIC_SCHED_CLOCK */
+
static bool __init hv_init_tsc_clocksource(void)
{
u64 tsc_msr;