From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- drivers/clocksource/timer-stm32-lp.c | 292 +++++++++++++++++++++++++++++++++++ 1 file changed, 292 insertions(+) create mode 100644 drivers/clocksource/timer-stm32-lp.c (limited to 'drivers/clocksource/timer-stm32-lp.c') diff --git a/drivers/clocksource/timer-stm32-lp.c b/drivers/clocksource/timer-stm32-lp.c new file mode 100644 index 000000000..3d804128c --- /dev/null +++ b/drivers/clocksource/timer-stm32-lp.c @@ -0,0 +1,292 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) STMicroelectronics 2019 - All Rights Reserved + * Authors: Benjamin Gaignard for STMicroelectronics. + * Pascal Paillet for STMicroelectronics. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define CFGR_PSC_OFFSET 9 +#define STM32_LP_RATING 1000 +#define STM32_TARGET_CLKRATE (32000 * HZ) +#define STM32_LP_MAX_PSC 7 + +struct stm32_lp_private { + struct regmap *reg; + struct clock_event_device clkevt; + unsigned long period; + u32 psc; + struct device *dev; + struct clk *clk; + u32 version; +}; + +static struct stm32_lp_private* +to_priv(struct clock_event_device *clkevt) +{ + return container_of(clkevt, struct stm32_lp_private, clkevt); +} + +static int stm32_clkevent_lp_shutdown(struct clock_event_device *clkevt) +{ + struct stm32_lp_private *priv = to_priv(clkevt); + + regmap_write(priv->reg, STM32_LPTIM_CR, 0); + regmap_write(priv->reg, STM32_LPTIM_IER, 0); + /* clear pending flags */ + regmap_write(priv->reg, STM32_LPTIM_ICR, STM32_LPTIM_ARRMCF); + + return 0; +} + +static int stm32mp25_clkevent_lp_set_evt(struct stm32_lp_private *priv, unsigned long evt) +{ + int ret; + u32 val; + + regmap_read(priv->reg, STM32_LPTIM_CR, &val); + if (!FIELD_GET(STM32_LPTIM_ENABLE, val)) { + /* Enable LPTIMER to be able to write into IER and ARR registers */ + regmap_write(priv->reg, STM32_LPTIM_CR, STM32_LPTIM_ENABLE); + /* + * After setting the ENABLE bit, a delay of two counter clock cycles is needed + * before the LPTIM is actually enabled. For 32KHz rate, this makes approximately + * 62.5 micro-seconds, round it up. + */ + udelay(63); + } + /* set next event counter */ + regmap_write(priv->reg, STM32_LPTIM_ARR, evt); + /* enable ARR interrupt */ + regmap_write(priv->reg, STM32_LPTIM_IER, STM32_LPTIM_ARRMIE); + + /* Poll DIEROK and ARROK to ensure register access has completed */ + ret = regmap_read_poll_timeout_atomic(priv->reg, STM32_LPTIM_ISR, val, + (val & STM32_LPTIM_DIEROK_ARROK) == + STM32_LPTIM_DIEROK_ARROK, + 10, 500); + if (ret) { + dev_err(priv->dev, "access to LPTIM timed out\n"); + /* Disable LPTIMER */ + regmap_write(priv->reg, STM32_LPTIM_CR, 0); + return ret; + } + /* Clear DIEROK and ARROK flags */ + regmap_write(priv->reg, STM32_LPTIM_ICR, STM32_LPTIM_DIEROKCF_ARROKCF); + + return 0; +} + +static void stm32_clkevent_lp_set_evt(struct stm32_lp_private *priv, unsigned long evt) +{ + /* disable LPTIMER to be able to write into IER register*/ + regmap_write(priv->reg, STM32_LPTIM_CR, 0); + /* enable ARR interrupt */ + regmap_write(priv->reg, STM32_LPTIM_IER, STM32_LPTIM_ARRMIE); + /* enable LPTIMER to be able to write into ARR register */ + regmap_write(priv->reg, STM32_LPTIM_CR, STM32_LPTIM_ENABLE); + /* set next event counter */ + regmap_write(priv->reg, STM32_LPTIM_ARR, evt); +} + +static int stm32_clkevent_lp_set_timer(unsigned long evt, + struct clock_event_device *clkevt, + int is_periodic) +{ + struct stm32_lp_private *priv = to_priv(clkevt); + int ret; + + if (priv->version == STM32_LPTIM_VERR_23) { + ret = stm32mp25_clkevent_lp_set_evt(priv, evt); + if (ret) + return ret; + } else { + stm32_clkevent_lp_set_evt(priv, evt); + } + + /* start counter */ + if (is_periodic) + regmap_write(priv->reg, STM32_LPTIM_CR, + STM32_LPTIM_CNTSTRT | STM32_LPTIM_ENABLE); + else + regmap_write(priv->reg, STM32_LPTIM_CR, + STM32_LPTIM_SNGSTRT | STM32_LPTIM_ENABLE); + + return 0; +} + +static int stm32_clkevent_lp_set_next_event(unsigned long evt, + struct clock_event_device *clkevt) +{ + return stm32_clkevent_lp_set_timer(evt, clkevt, + clockevent_state_periodic(clkevt)); +} + +static int stm32_clkevent_lp_set_periodic(struct clock_event_device *clkevt) +{ + struct stm32_lp_private *priv = to_priv(clkevt); + + return stm32_clkevent_lp_set_timer(priv->period, clkevt, true); +} + +static int stm32_clkevent_lp_set_oneshot(struct clock_event_device *clkevt) +{ + struct stm32_lp_private *priv = to_priv(clkevt); + + return stm32_clkevent_lp_set_timer(priv->period, clkevt, false); +} + +static irqreturn_t stm32_clkevent_lp_irq_handler(int irq, void *dev_id) +{ + struct clock_event_device *clkevt = (struct clock_event_device *)dev_id; + struct stm32_lp_private *priv = to_priv(clkevt); + + regmap_write(priv->reg, STM32_LPTIM_ICR, STM32_LPTIM_ARRMCF); + + if (clkevt->event_handler) + clkevt->event_handler(clkevt); + + return IRQ_HANDLED; +} + +static void stm32_clkevent_lp_set_prescaler(struct stm32_lp_private *priv, + unsigned long *rate) +{ + int i; + + for (i = 0; i <= STM32_LP_MAX_PSC; i++) { + if (DIV_ROUND_CLOSEST(*rate, 1 << i) < STM32_TARGET_CLKRATE) + break; + } + + regmap_write(priv->reg, STM32_LPTIM_CFGR, i << CFGR_PSC_OFFSET); + + /* Adjust rate and period given the prescaler value */ + *rate = DIV_ROUND_CLOSEST(*rate, (1 << i)); + priv->period = DIV_ROUND_UP(*rate, HZ); + priv->psc = i; +} + +static void stm32_clkevent_lp_suspend(struct clock_event_device *clkevt) +{ + struct stm32_lp_private *priv = to_priv(clkevt); + + stm32_clkevent_lp_shutdown(clkevt); + + /* balance clk_prepare_enable() from the probe */ + clk_disable_unprepare(priv->clk); +} + +static void stm32_clkevent_lp_resume(struct clock_event_device *clkevt) +{ + struct stm32_lp_private *priv = to_priv(clkevt); + + clk_prepare_enable(priv->clk); + + /* restore prescaler */ + regmap_write(priv->reg, STM32_LPTIM_CFGR, priv->psc << CFGR_PSC_OFFSET); +} + +static void stm32_clkevent_lp_init(struct stm32_lp_private *priv, + struct device_node *np, unsigned long rate) +{ + priv->clkevt.name = np->full_name; + priv->clkevt.cpumask = cpu_possible_mask; + priv->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | + CLOCK_EVT_FEAT_ONESHOT; + priv->clkevt.set_state_shutdown = stm32_clkevent_lp_shutdown; + priv->clkevt.set_state_periodic = stm32_clkevent_lp_set_periodic; + priv->clkevt.set_state_oneshot = stm32_clkevent_lp_set_oneshot; + priv->clkevt.set_next_event = stm32_clkevent_lp_set_next_event; + priv->clkevt.rating = STM32_LP_RATING; + priv->clkevt.suspend = stm32_clkevent_lp_suspend; + priv->clkevt.resume = stm32_clkevent_lp_resume; + priv->clkevt.owner = THIS_MODULE; + + clockevents_config_and_register(&priv->clkevt, rate, 0x1, + STM32_LPTIM_MAX_ARR); +} + +static int stm32_clkevent_lp_probe(struct platform_device *pdev) +{ + struct stm32_lptimer *ddata = dev_get_drvdata(pdev->dev.parent); + struct stm32_lp_private *priv; + unsigned long rate; + int ret, irq; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->reg = ddata->regmap; + priv->version = ddata->version; + priv->clk = ddata->clk; + ret = clk_prepare_enable(priv->clk); + if (ret) + return -EINVAL; + + rate = clk_get_rate(priv->clk); + if (!rate) { + ret = -EINVAL; + goto out_clk_disable; + } + + irq = platform_get_irq(to_platform_device(pdev->dev.parent), 0); + if (irq <= 0) { + ret = irq; + goto out_clk_disable; + } + + if (of_property_read_bool(pdev->dev.parent->of_node, "wakeup-source")) { + device_set_wakeup_capable(&pdev->dev, true); + + ret = dev_pm_set_wake_irq(&pdev->dev, irq); + if (ret) + goto out_clk_disable; + } + + ret = devm_request_irq(&pdev->dev, irq, stm32_clkevent_lp_irq_handler, + IRQF_TIMER, pdev->name, &priv->clkevt); + if (ret) + goto out_clk_disable; + + stm32_clkevent_lp_set_prescaler(priv, &rate); + + stm32_clkevent_lp_init(priv, pdev->dev.parent->of_node, rate); + + priv->dev = &pdev->dev; + + return 0; + +out_clk_disable: + clk_disable_unprepare(priv->clk); + return ret; +} + +static const struct of_device_id stm32_clkevent_lp_of_match[] = { + { .compatible = "st,stm32-lptimer-timer", }, + {}, +}; +MODULE_DEVICE_TABLE(of, stm32_clkevent_lp_of_match); + +static struct platform_driver stm32_clkevent_lp_driver = { + .probe = stm32_clkevent_lp_probe, + .driver = { + .name = "stm32-lptimer-timer", + .of_match_table = stm32_clkevent_lp_of_match, + .suppress_bind_attrs = true, + }, +}; +module_platform_driver(stm32_clkevent_lp_driver); + +MODULE_DESCRIPTION("STMicroelectronics STM32 clockevent low power driver"); -- cgit v1.3.1