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authorLinus Torvalds <torvalds@linux-foundation.org>2018-03-04 11:34:49 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-03-04 11:34:49 -0800
commit4c4ce3022dc7352d05de4d8e1602c9a2a14458bf (patch)
tree303d93fe80bb913ed780b82c2ef911026db1f170
parentff8d583621143d26123ac1e14470de9bd2384a31 (diff)
parentc52232a49e203a65a6e1a670cd5262f59e9364a0 (diff)
downloadlwn-4c4ce3022dc7352d05de4d8e1602c9a2a14458bf.tar.gz
lwn-4c4ce3022dc7352d05de4d8e1602c9a2a14458bf.zip
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Thomas Gleixner: "A small set of fixes from the timer departement: - Add a missing timer wheel clock forward when migrating timers off a unplugged CPU to prevent operating on a stale clock base and missing timer deadlines. - Use the proper shift count to extract data from a register value to prevent evaluating unrelated bits - Make the error return check in the FSL timer driver work correctly. Checking an unsigned variable for less than zero does not really work well. - Clarify the confusing comments in the ARC timer code" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timers: Forward timer base before migrating timers clocksource/drivers/arc_timer: Update some comments clocksource/drivers/mips-gic-timer: Use correct shift count to extract data clocksource/drivers/fsl_ftm_timer: Fix error return checking
-rw-r--r--drivers/clocksource/arc_timer.c11
-rw-r--r--drivers/clocksource/fsl_ftm_timer.c2
-rw-r--r--drivers/clocksource/mips-gic-timer.c2
-rw-r--r--kernel/time/timer.c6
4 files changed, 16 insertions, 5 deletions
diff --git a/drivers/clocksource/arc_timer.c b/drivers/clocksource/arc_timer.c
index 4927355f9cbe..471b428d8034 100644
--- a/drivers/clocksource/arc_timer.c
+++ b/drivers/clocksource/arc_timer.c
@@ -251,9 +251,14 @@ static irqreturn_t timer_irq_handler(int irq, void *dev_id)
int irq_reenable = clockevent_state_periodic(evt);
/*
- * Any write to CTRL reg ACks the interrupt, we rewrite the
- * Count when [N]ot [H]alted bit.
- * And re-arm it if perioid by [I]nterrupt [E]nable bit
+ * 1. ACK the interrupt
+ * - For ARC700, any write to CTRL reg ACKs it, so just rewrite
+ * Count when [N]ot [H]alted bit.
+ * - For HS3x, it is a bit subtle. On taken count-down interrupt,
+ * IP bit [3] is set, which needs to be cleared for ACK'ing.
+ * The write below can only update the other two bits, hence
+ * explicitly clears IP bit
+ * 2. Re-arm interrupt if periodic by writing to IE bit [0]
*/
write_aux_reg(ARC_REG_TIMER0_CTRL, irq_reenable | TIMER_CTRL_NH);
diff --git a/drivers/clocksource/fsl_ftm_timer.c b/drivers/clocksource/fsl_ftm_timer.c
index 3ee7e6fea621..846d18daf893 100644
--- a/drivers/clocksource/fsl_ftm_timer.c
+++ b/drivers/clocksource/fsl_ftm_timer.c
@@ -281,7 +281,7 @@ static int __init __ftm_clk_init(struct device_node *np, char *cnt_name,
static unsigned long __init ftm_clk_init(struct device_node *np)
{
- unsigned long freq;
+ long freq;
freq = __ftm_clk_init(np, "ftm-evt-counter-en", "ftm-evt");
if (freq <= 0)
diff --git a/drivers/clocksource/mips-gic-timer.c b/drivers/clocksource/mips-gic-timer.c
index 65e18c86d9b9..986b6796b631 100644
--- a/drivers/clocksource/mips-gic-timer.c
+++ b/drivers/clocksource/mips-gic-timer.c
@@ -166,7 +166,7 @@ static int __init __gic_clocksource_init(void)
/* Set clocksource mask. */
count_width = read_gic_config() & GIC_CONFIG_COUNTBITS;
- count_width >>= __fls(GIC_CONFIG_COUNTBITS);
+ count_width >>= __ffs(GIC_CONFIG_COUNTBITS);
count_width *= 4;
count_width += 32;
gic_clocksource.mask = CLOCKSOURCE_MASK(count_width);
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 48150ab42de9..4a4fd567fb26 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1894,6 +1894,12 @@ int timers_dead_cpu(unsigned int cpu)
raw_spin_lock_irq(&new_base->lock);
raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
+ /*
+ * The current CPUs base clock might be stale. Update it
+ * before moving the timers over.
+ */
+ forward_timer_base(new_base);
+
BUG_ON(old_base->running_timer);
for (i = 0; i < WHEEL_SIZE; i++)