From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- drivers/clocksource/clps711x-timer.c | 110 +++++++++++++++++++++++++++++++++++ 1 file changed, 110 insertions(+) create mode 100644 drivers/clocksource/clps711x-timer.c (limited to 'drivers/clocksource/clps711x-timer.c') diff --git a/drivers/clocksource/clps711x-timer.c b/drivers/clocksource/clps711x-timer.c new file mode 100644 index 000000000..63ae3a691 --- /dev/null +++ b/drivers/clocksource/clps711x-timer.c @@ -0,0 +1,110 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Cirrus Logic CLPS711X clocksource driver + * + * Copyright (C) 2014 Alexander Shiyan + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +enum { + CLPS711X_CLKSRC_CLOCKSOURCE, + CLPS711X_CLKSRC_CLOCKEVENT, +}; + +static void __iomem *tcd; + +static u64 notrace clps711x_sched_clock_read(void) +{ + return ~readw(tcd); +} + +static void __init clps711x_clksrc_init(struct clk *clock, void __iomem *base) +{ + unsigned long rate = clk_get_rate(clock); + + tcd = base; + + clocksource_mmio_init(tcd, "clps711x-clocksource", rate, 300, 16, + clocksource_mmio_readw_down); + + sched_clock_register(clps711x_sched_clock_read, 16, rate); +} + +static irqreturn_t clps711x_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static int __init _clps711x_clkevt_init(struct clk *clock, void __iomem *base, + unsigned int irq) +{ + struct clock_event_device *clkevt; + unsigned long rate; + + clkevt = kzalloc_obj(*clkevt); + if (!clkevt) + return -ENOMEM; + + rate = clk_get_rate(clock); + + /* Set Timer prescaler */ + writew(DIV_ROUND_CLOSEST(rate, HZ), base); + + clkevt->name = "clps711x-clockevent"; + clkevt->rating = 300; + clkevt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_C3STOP; + clkevt->cpumask = cpumask_of(0); + clockevents_config_and_register(clkevt, HZ, 0, 0); + + return request_irq(irq, clps711x_timer_interrupt, IRQF_TIMER, + "clps711x-timer", clkevt); +} + +static int __init clps711x_timer_init(struct device_node *np) +{ + unsigned int irq = irq_of_parse_and_map(np, 0); + struct clk *clock = of_clk_get(np, 0); + void __iomem *base = of_iomap(np, 0); + int ret = 0; + + if (!base) + return -ENOMEM; + if (!irq) { + ret = -EINVAL; + goto unmap_io; + } + if (IS_ERR(clock)) { + ret = PTR_ERR(clock); + goto unmap_io; + } + + switch (of_alias_get_id(np, "timer")) { + case CLPS711X_CLKSRC_CLOCKSOURCE: + clps711x_clksrc_init(clock, base); + return 0; + case CLPS711X_CLKSRC_CLOCKEVENT: + ret = _clps711x_clkevt_init(clock, base, irq); + break; + default: + ret = -EINVAL; + break; + } + +unmap_io: + iounmap(base); + return ret; +} +TIMER_OF_DECLARE(clps711x, "cirrus,ep7209-timer", clps711x_timer_init); -- cgit v1.3.1