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/timer-milbeaut.c | 189 +++++++++++++++++++++++++++++++++++ 1 file changed, 189 insertions(+) create mode 100644 drivers/clocksource/timer-milbeaut.c (limited to 'drivers/clocksource/timer-milbeaut.c') diff --git a/drivers/clocksource/timer-milbeaut.c b/drivers/clocksource/timer-milbeaut.c new file mode 100644 index 000000000..fa9fb4eac --- /dev/null +++ b/drivers/clocksource/timer-milbeaut.c @@ -0,0 +1,189 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2018 Socionext Inc. + */ + +#include +#include +#include +#include +#include +#include "timer-of.h" + +#define MLB_TMR_TMCSR_OFS 0x0 +#define MLB_TMR_TMR_OFS 0x4 +#define MLB_TMR_TMRLR1_OFS 0x8 +#define MLB_TMR_TMRLR2_OFS 0xc +#define MLB_TMR_REGSZPCH 0x10 + +#define MLB_TMR_TMCSR_OUTL BIT(5) +#define MLB_TMR_TMCSR_RELD BIT(4) +#define MLB_TMR_TMCSR_INTE BIT(3) +#define MLB_TMR_TMCSR_UF BIT(2) +#define MLB_TMR_TMCSR_CNTE BIT(1) +#define MLB_TMR_TMCSR_TRG BIT(0) + +#define MLB_TMR_TMCSR_CSL_DIV2 0 +#define MLB_TMR_DIV_CNT 2 + +#define MLB_TMR_SRC_CH 1 +#define MLB_TMR_EVT_CH 0 + +#define MLB_TMR_SRC_CH_OFS (MLB_TMR_REGSZPCH * MLB_TMR_SRC_CH) +#define MLB_TMR_EVT_CH_OFS (MLB_TMR_REGSZPCH * MLB_TMR_EVT_CH) + +#define MLB_TMR_SRC_TMCSR_OFS (MLB_TMR_SRC_CH_OFS + MLB_TMR_TMCSR_OFS) +#define MLB_TMR_SRC_TMR_OFS (MLB_TMR_SRC_CH_OFS + MLB_TMR_TMR_OFS) +#define MLB_TMR_SRC_TMRLR1_OFS (MLB_TMR_SRC_CH_OFS + MLB_TMR_TMRLR1_OFS) +#define MLB_TMR_SRC_TMRLR2_OFS (MLB_TMR_SRC_CH_OFS + MLB_TMR_TMRLR2_OFS) + +#define MLB_TMR_EVT_TMCSR_OFS (MLB_TMR_EVT_CH_OFS + MLB_TMR_TMCSR_OFS) +#define MLB_TMR_EVT_TMR_OFS (MLB_TMR_EVT_CH_OFS + MLB_TMR_TMR_OFS) +#define MLB_TMR_EVT_TMRLR1_OFS (MLB_TMR_EVT_CH_OFS + MLB_TMR_TMRLR1_OFS) +#define MLB_TMR_EVT_TMRLR2_OFS (MLB_TMR_EVT_CH_OFS + MLB_TMR_TMRLR2_OFS) + +#define MLB_TIMER_RATING 500 +#define MLB_TIMER_ONESHOT 0 +#define MLB_TIMER_PERIODIC 1 + +static irqreturn_t mlb_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *clk = dev_id; + struct timer_of *to = to_timer_of(clk); + u32 val; + + val = readl_relaxed(timer_of_base(to) + MLB_TMR_EVT_TMCSR_OFS); + val &= ~MLB_TMR_TMCSR_UF; + writel_relaxed(val, timer_of_base(to) + MLB_TMR_EVT_TMCSR_OFS); + + clk->event_handler(clk); + + return IRQ_HANDLED; +} + +static void mlb_evt_timer_start(struct timer_of *to, bool periodic) +{ + u32 val = MLB_TMR_TMCSR_CSL_DIV2; + + val |= MLB_TMR_TMCSR_CNTE | MLB_TMR_TMCSR_TRG | MLB_TMR_TMCSR_INTE; + if (periodic) + val |= MLB_TMR_TMCSR_RELD; + writel_relaxed(val, timer_of_base(to) + MLB_TMR_EVT_TMCSR_OFS); +} + +static void mlb_evt_timer_stop(struct timer_of *to) +{ + u32 val = readl_relaxed(timer_of_base(to) + MLB_TMR_EVT_TMCSR_OFS); + + val &= ~MLB_TMR_TMCSR_CNTE; + writel_relaxed(val, timer_of_base(to) + MLB_TMR_EVT_TMCSR_OFS); +} + +static void mlb_evt_timer_register_count(struct timer_of *to, unsigned long cnt) +{ + writel_relaxed(cnt, timer_of_base(to) + MLB_TMR_EVT_TMRLR1_OFS); +} + +static int mlb_set_state_periodic(struct clock_event_device *clk) +{ + struct timer_of *to = to_timer_of(clk); + + mlb_evt_timer_stop(to); + mlb_evt_timer_register_count(to, to->of_clk.period); + mlb_evt_timer_start(to, MLB_TIMER_PERIODIC); + return 0; +} + +static int mlb_set_state_oneshot(struct clock_event_device *clk) +{ + struct timer_of *to = to_timer_of(clk); + + mlb_evt_timer_stop(to); + mlb_evt_timer_start(to, MLB_TIMER_ONESHOT); + return 0; +} + +static int mlb_set_state_shutdown(struct clock_event_device *clk) +{ + struct timer_of *to = to_timer_of(clk); + + mlb_evt_timer_stop(to); + return 0; +} + +static int mlb_clkevt_next_event(unsigned long event, + struct clock_event_device *clk) +{ + struct timer_of *to = to_timer_of(clk); + + mlb_evt_timer_stop(to); + mlb_evt_timer_register_count(to, event); + mlb_evt_timer_start(to, MLB_TIMER_ONESHOT); + return 0; +} + +static int mlb_config_clock_source(struct timer_of *to) +{ + u32 val = MLB_TMR_TMCSR_CSL_DIV2; + + writel_relaxed(val, timer_of_base(to) + MLB_TMR_SRC_TMCSR_OFS); + writel_relaxed(~0, timer_of_base(to) + MLB_TMR_SRC_TMRLR1_OFS); + writel_relaxed(~0, timer_of_base(to) + MLB_TMR_SRC_TMRLR2_OFS); + val |= MLB_TMR_TMCSR_RELD | MLB_TMR_TMCSR_CNTE | MLB_TMR_TMCSR_TRG; + writel_relaxed(val, timer_of_base(to) + MLB_TMR_SRC_TMCSR_OFS); + return 0; +} + +static int mlb_config_clock_event(struct timer_of *to) +{ + writel_relaxed(0, timer_of_base(to) + MLB_TMR_EVT_TMCSR_OFS); + return 0; +} + +static struct timer_of to = { + .flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK, + + .clkevt = { + .name = "mlb-clkevt", + .rating = MLB_TIMER_RATING, + .cpumask = cpu_possible_mask, + .features = CLOCK_EVT_FEAT_DYNIRQ | CLOCK_EVT_FEAT_ONESHOT, + .set_state_oneshot = mlb_set_state_oneshot, + .set_state_periodic = mlb_set_state_periodic, + .set_state_shutdown = mlb_set_state_shutdown, + .set_next_event = mlb_clkevt_next_event, + }, + + .of_irq = { + .flags = IRQF_TIMER | IRQF_IRQPOLL, + .handler = mlb_timer_interrupt, + }, +}; + +static u64 notrace mlb_timer_sched_read(void) +{ + return ~readl_relaxed(timer_of_base(&to) + MLB_TMR_SRC_TMR_OFS); +} + +static int __init mlb_timer_init(struct device_node *node) +{ + int ret; + unsigned long rate; + + ret = timer_of_init(node, &to); + if (ret) + return ret; + + rate = timer_of_rate(&to) / MLB_TMR_DIV_CNT; + mlb_config_clock_source(&to); + clocksource_mmio_init(timer_of_base(&to) + MLB_TMR_SRC_TMR_OFS, + node->name, rate, MLB_TIMER_RATING, 32, + clocksource_mmio_readl_down); + sched_clock_register(mlb_timer_sched_read, 32, rate); + mlb_config_clock_event(&to); + clockevents_config_and_register(&to.clkevt, timer_of_rate(&to), 15, + 0xffffffff); + return 0; +} +TIMER_OF_DECLARE(mlb_peritimer, "socionext,milbeaut-timer", + mlb_timer_init); -- cgit v1.3.1