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authorJohannes Berg <johannes.berg@intel.com>2020-02-13 14:26:48 +0100
committerRichard Weinberger <richard@nod.at>2020-03-29 23:29:52 +0200
commit0bc8fb4dda2b461491ec567b2333d13897780d8c (patch)
treeced5713f42b176386f212534ecf07822088d3709 /arch/um
parent88ce642492339f49a0b391af40e5798c08948e49 (diff)
downloadlinux-0bc8fb4dda2b461491ec567b2333d13897780d8c.tar.bz2
um: Implement ndelay/udelay in time-travel mode
In external or inf-cpu time-travel mode, ndelay/udelay currently just waste CPU time since the simulation time doesn't advance. Implement them properly in this case. Note that the "if (time_travel_mode == ...)" parts compile out if CONFIG_UML_TIME_TRAVEL_SUPPORT isn't set, time_travel_mode is defined to TT_MODE_OFF in that case. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/include/asm/Kbuild1
-rw-r--r--arch/um/include/asm/delay.h30
-rw-r--r--arch/um/include/linux/time-internal.h6
-rw-r--r--arch/um/kernel/time.c6
4 files changed, 42 insertions, 1 deletions
diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild
index db7d9d4e30d8..8d435f8a6dec 100644
--- a/arch/um/include/asm/Kbuild
+++ b/arch/um/include/asm/Kbuild
@@ -3,7 +3,6 @@ generic-y += bpf_perf_event.h
generic-y += bug.h
generic-y += compat.h
generic-y += current.h
-generic-y += delay.h
generic-y += device.h
generic-y += emergency-restart.h
generic-y += exec.h
diff --git a/arch/um/include/asm/delay.h b/arch/um/include/asm/delay.h
new file mode 100644
index 000000000000..56fc2b8f2dd0
--- /dev/null
+++ b/arch/um/include/asm/delay.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __UM_DELAY_H
+#define __UM_DELAY_H
+#include <asm-generic/delay.h>
+#include <linux/time-internal.h>
+
+static inline void um_ndelay(unsigned long nsecs)
+{
+ if (time_travel_mode == TT_MODE_INFCPU ||
+ time_travel_mode == TT_MODE_EXTERNAL) {
+ time_travel_ndelay(nsecs);
+ return;
+ }
+ ndelay(nsecs);
+}
+#undef ndelay
+#define ndelay um_ndelay
+
+static inline void um_udelay(unsigned long usecs)
+{
+ if (time_travel_mode == TT_MODE_INFCPU ||
+ time_travel_mode == TT_MODE_EXTERNAL) {
+ time_travel_ndelay(1000 * usecs);
+ return;
+ }
+ udelay(usecs);
+}
+#undef udelay
+#define udelay um_udelay
+#endif /* __UM_DELAY_H */
diff --git a/arch/um/include/linux/time-internal.h b/arch/um/include/linux/time-internal.h
index e21655926f08..f3b03d39a854 100644
--- a/arch/um/include/linux/time-internal.h
+++ b/arch/um/include/linux/time-internal.h
@@ -75,4 +75,10 @@ static inline void time_travel_wait_readable(int fd)
{
}
#endif /* CONFIG_UML_TIME_TRAVEL_SUPPORT */
+
+/*
+ * Without CONFIG_UML_TIME_TRAVEL_SUPPORT this is a linker error if used,
+ * which is intentional since we really shouldn't link it in that case.
+ */
+void time_travel_ndelay(unsigned long nsec);
#endif /* __TIMER_INTERNAL_H__ */
diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c
index 15c4825b857e..25eaa6a0c658 100644
--- a/arch/um/kernel/time.c
+++ b/arch/um/kernel/time.c
@@ -374,6 +374,12 @@ static void time_travel_update_time(unsigned long long next, bool idle)
time_travel_del_event(&ne);
}
+void time_travel_ndelay(unsigned long nsec)
+{
+ time_travel_update_time(time_travel_time + nsec, false);
+}
+EXPORT_SYMBOL(time_travel_ndelay);
+
void time_travel_add_irq_event(struct time_travel_event *e)
{
BUG_ON(time_travel_mode != TT_MODE_EXTERNAL);