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authorPeter Zijlstra <peterz@infradead.org>2023-05-19 13:21:04 +0300
committerPeter Zijlstra <peterz@infradead.org>2023-06-05 22:11:06 +0300
commit91b41a237512b569746e1f560a42d9fba077261d (patch)
tree03db4aa84444888fb7d7d731fe61575fe58b47e3
parent6b10fef09f937433563822f4bb6a2f947176e5a0 (diff)
downloadlinux-91b41a237512b569746e1f560a42d9fba077261d.tar.xz
s390/time: Provide sched_clock_noinstr()
With the intent to provide local_clock_noinstr(), a variant of local_clock() that's safe to be called from noinstr code (with the assumption that any such code will already be non-preemptible), prepare for things by providing a noinstr sched_clock_noinstr() function. Specifically, preempt_enable_*() calls out to schedule(), which upsets noinstr validation efforts. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Heiko Carstens <hca@linux.ibm.com> Tested-by: Michael Kelley <mikelley@microsoft.com> # Hyper-V Link: https://lore.kernel.org/r/20230519102715.570170436@infradead.org
-rw-r--r--arch/s390/include/asm/timex.h13
-rw-r--r--arch/s390/kernel/time.c5
2 files changed, 14 insertions, 4 deletions
diff --git a/arch/s390/include/asm/timex.h b/arch/s390/include/asm/timex.h
index ce878e85b6e4..4d646659a5f5 100644
--- a/arch/s390/include/asm/timex.h
+++ b/arch/s390/include/asm/timex.h
@@ -63,7 +63,7 @@ static inline int store_tod_clock_ext_cc(union tod_clock *clk)
return cc;
}
-static inline void store_tod_clock_ext(union tod_clock *tod)
+static __always_inline void store_tod_clock_ext(union tod_clock *tod)
{
asm volatile("stcke %0" : "=Q" (*tod) : : "cc");
}
@@ -177,7 +177,7 @@ static inline void local_tick_enable(unsigned long comp)
typedef unsigned long cycles_t;
-static inline unsigned long get_tod_clock(void)
+static __always_inline unsigned long get_tod_clock(void)
{
union tod_clock clk;
@@ -204,6 +204,11 @@ void init_cpu_timer(void);
extern union tod_clock tod_clock_base;
+static __always_inline unsigned long __get_tod_clock_monotonic(void)
+{
+ return get_tod_clock() - tod_clock_base.tod;
+}
+
/**
* get_clock_monotonic - returns current time in clock rate units
*
@@ -216,7 +221,7 @@ static inline unsigned long get_tod_clock_monotonic(void)
unsigned long tod;
preempt_disable_notrace();
- tod = get_tod_clock() - tod_clock_base.tod;
+ tod = __get_tod_clock_monotonic();
preempt_enable_notrace();
return tod;
}
@@ -240,7 +245,7 @@ static inline unsigned long get_tod_clock_monotonic(void)
* -> ns = (th * 125) + ((tl * 125) >> 9);
*
*/
-static inline unsigned long tod_to_ns(unsigned long todval)
+static __always_inline unsigned long tod_to_ns(unsigned long todval)
{
return ((todval >> 9) * 125) + (((todval & 0x1ff) * 125) >> 9);
}
diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
index 6b7b6d5e3632..276278199c44 100644
--- a/arch/s390/kernel/time.c
+++ b/arch/s390/kernel/time.c
@@ -102,6 +102,11 @@ void __init time_early_init(void)
((long) qui.old_leap * 4096000000L);
}
+unsigned long long noinstr sched_clock_noinstr(void)
+{
+ return tod_to_ns(__get_tod_clock_monotonic());
+}
+
/*
* Scheduler clock - returns current time in nanosec units.
*/