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-zevio.c | 213 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 213 insertions(+) create mode 100644 drivers/clocksource/timer-zevio.c (limited to 'drivers/clocksource/timer-zevio.c') diff --git a/drivers/clocksource/timer-zevio.c b/drivers/clocksource/timer-zevio.c new file mode 100644 index 000000000..9a67b84b3 --- /dev/null +++ b/drivers/clocksource/timer-zevio.c @@ -0,0 +1,213 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/drivers/clocksource/zevio-timer.c + * + * Copyright (C) 2013 Daniel Tang + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define IO_CURRENT_VAL 0x00 +#define IO_DIVIDER 0x04 +#define IO_CONTROL 0x08 + +#define IO_TIMER1 0x00 +#define IO_TIMER2 0x0C + +#define IO_MATCH_BEGIN 0x18 +#define IO_MATCH(x) (IO_MATCH_BEGIN + ((x) << 2)) + +#define IO_INTR_STS 0x00 +#define IO_INTR_ACK 0x00 +#define IO_INTR_MSK 0x04 + +#define CNTL_STOP_TIMER (1 << 4) +#define CNTL_RUN_TIMER (0 << 4) + +#define CNTL_INC (1 << 3) +#define CNTL_DEC (0 << 3) + +#define CNTL_TOZERO 0 +#define CNTL_MATCH(x) ((x) + 1) +#define CNTL_FOREVER 7 + +/* There are 6 match registers but we only use one. */ +#define TIMER_MATCH 0 + +#define TIMER_INTR_MSK (1 << (TIMER_MATCH)) +#define TIMER_INTR_ALL 0x3F + +struct zevio_timer { + void __iomem *base; + void __iomem *timer1, *timer2; + void __iomem *interrupt_regs; + + struct clk *clk; + struct clock_event_device clkevt; + + char clocksource_name[64]; + char clockevent_name[64]; +}; + +static int zevio_timer_set_event(unsigned long delta, + struct clock_event_device *dev) +{ + struct zevio_timer *timer = container_of(dev, struct zevio_timer, + clkevt); + + writel(delta, timer->timer1 + IO_CURRENT_VAL); + writel(CNTL_RUN_TIMER | CNTL_DEC | CNTL_MATCH(TIMER_MATCH), + timer->timer1 + IO_CONTROL); + + return 0; +} + +static int zevio_timer_shutdown(struct clock_event_device *dev) +{ + struct zevio_timer *timer = container_of(dev, struct zevio_timer, + clkevt); + + /* Disable timer interrupts */ + writel(0, timer->interrupt_regs + IO_INTR_MSK); + writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK); + /* Stop timer */ + writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL); + return 0; +} + +static int zevio_timer_set_oneshot(struct clock_event_device *dev) +{ + struct zevio_timer *timer = container_of(dev, struct zevio_timer, + clkevt); + + /* Enable timer interrupts */ + writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_MSK); + writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK); + return 0; +} + +static irqreturn_t zevio_timer_interrupt(int irq, void *dev_id) +{ + struct zevio_timer *timer = dev_id; + u32 intr; + + intr = readl(timer->interrupt_regs + IO_INTR_ACK); + if (!(intr & TIMER_INTR_MSK)) + return IRQ_NONE; + + writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_ACK); + writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL); + + if (timer->clkevt.event_handler) + timer->clkevt.event_handler(&timer->clkevt); + + return IRQ_HANDLED; +} + +static int __init zevio_timer_add(struct device_node *node) +{ + struct zevio_timer *timer; + struct resource res; + int irqnr, ret; + + timer = kzalloc_obj(*timer); + if (!timer) + return -ENOMEM; + + timer->base = of_iomap(node, 0); + if (!timer->base) { + ret = -EINVAL; + goto error_free; + } + timer->timer1 = timer->base + IO_TIMER1; + timer->timer2 = timer->base + IO_TIMER2; + + timer->clk = of_clk_get(node, 0); + if (IS_ERR(timer->clk)) { + ret = PTR_ERR(timer->clk); + pr_err("Timer clock not found! (error %d)\n", ret); + goto error_unmap; + } + + timer->interrupt_regs = of_iomap(node, 1); + irqnr = irq_of_parse_and_map(node, 0); + + of_address_to_resource(node, 0, &res); + scnprintf(timer->clocksource_name, sizeof(timer->clocksource_name), + "%llx.%pOFn_clocksource", + (unsigned long long)res.start, node); + + scnprintf(timer->clockevent_name, sizeof(timer->clockevent_name), + "%llx.%pOFn_clockevent", + (unsigned long long)res.start, node); + + if (timer->interrupt_regs && irqnr) { + timer->clkevt.name = timer->clockevent_name; + timer->clkevt.set_next_event = zevio_timer_set_event; + timer->clkevt.set_state_shutdown = zevio_timer_shutdown; + timer->clkevt.set_state_oneshot = zevio_timer_set_oneshot; + timer->clkevt.tick_resume = zevio_timer_set_oneshot; + timer->clkevt.rating = 200; + timer->clkevt.cpumask = cpu_possible_mask; + timer->clkevt.features = CLOCK_EVT_FEAT_ONESHOT; + timer->clkevt.irq = irqnr; + + writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL); + writel(0, timer->timer1 + IO_DIVIDER); + + /* Start with timer interrupts disabled */ + writel(0, timer->interrupt_regs + IO_INTR_MSK); + writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK); + + /* Interrupt to occur when timer value matches 0 */ + writel(0, timer->base + IO_MATCH(TIMER_MATCH)); + + if (request_irq(irqnr, zevio_timer_interrupt, + IRQF_TIMER | IRQF_IRQPOLL, + timer->clockevent_name, timer)) { + pr_err("%s: request_irq() failed\n", + timer->clockevent_name); + } + + clockevents_config_and_register(&timer->clkevt, + clk_get_rate(timer->clk), 0x0001, 0xffff); + pr_info("Added %s as clockevent\n", timer->clockevent_name); + } + + writel(CNTL_STOP_TIMER, timer->timer2 + IO_CONTROL); + writel(0, timer->timer2 + IO_CURRENT_VAL); + writel(0, timer->timer2 + IO_DIVIDER); + writel(CNTL_RUN_TIMER | CNTL_FOREVER | CNTL_INC, + timer->timer2 + IO_CONTROL); + + clocksource_mmio_init(timer->timer2 + IO_CURRENT_VAL, + timer->clocksource_name, + clk_get_rate(timer->clk), + 200, 16, + clocksource_mmio_readw_up); + + pr_info("Added %s as clocksource\n", timer->clocksource_name); + + return 0; +error_unmap: + iounmap(timer->base); +error_free: + kfree(timer); + return ret; +} + +static int __init zevio_timer_init(struct device_node *node) +{ + return zevio_timer_add(node); +} + +TIMER_OF_DECLARE(zevio_timer, "lsi,zevio-timer", zevio_timer_init); -- cgit v1.3.1