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-nxp-pit.c | 385 ++++++++++++++++++++++++++++++++++++ 1 file changed, 385 insertions(+) create mode 100644 drivers/clocksource/timer-nxp-pit.c (limited to 'drivers/clocksource/timer-nxp-pit.c') diff --git a/drivers/clocksource/timer-nxp-pit.c b/drivers/clocksource/timer-nxp-pit.c new file mode 100644 index 000000000..2f70d1d5e --- /dev/null +++ b/drivers/clocksource/timer-nxp-pit.c @@ -0,0 +1,385 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright 2012-2013 Freescale Semiconductor, Inc. + * Copyright 2018,2021-2025 NXP + */ +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * Each pit takes 0x10 Bytes register space + */ +#define PIT0_OFFSET 0x100 +#define PIT_CH(n) (PIT0_OFFSET + 0x10 * (n)) + +#define PITMCR(__base) (__base) + +#define PITMCR_FRZ BIT(0) +#define PITMCR_MDIS BIT(1) + +#define PITLDVAL(__base) (__base) +#define PITTCTRL(__base) ((__base) + 0x08) + +#define PITCVAL_OFFSET 0x04 +#define PITCVAL(__base) ((__base) + 0x04) + +#define PITTCTRL_TEN BIT(0) +#define PITTCTRL_TIE BIT(1) + +#define PITTFLG(__base) ((__base) + 0x0c) + +#define PITTFLG_TIF BIT(0) + +struct pit_timer { + void __iomem *clksrc_base; + void __iomem *clkevt_base; + struct clock_event_device ced; + struct clocksource cs; + int rate; +}; + +struct pit_timer_data { + int max_pit_instances; +}; + +static DEFINE_PER_CPU(struct pit_timer *, pit_timers); + +/* + * Global structure for multiple PITs initialization + */ +static int pit_instances; +static int max_pit_instances = 1; + +static void __iomem *sched_clock_base; + +static inline struct pit_timer *ced_to_pit(struct clock_event_device *ced) +{ + return container_of(ced, struct pit_timer, ced); +} + +static inline struct pit_timer *cs_to_pit(struct clocksource *cs) +{ + return container_of(cs, struct pit_timer, cs); +} + +static inline void pit_module_enable(void __iomem *base) +{ + writel(0, PITMCR(base)); +} + +static inline void pit_module_disable(void __iomem *base) +{ + writel(PITMCR_MDIS, PITMCR(base)); +} + +static inline void pit_timer_enable(void __iomem *base, bool tie) +{ + u32 val = PITTCTRL_TEN | (tie ? PITTCTRL_TIE : 0); + + writel(val, PITTCTRL(base)); +} + +static inline void pit_timer_disable(void __iomem *base) +{ + writel(0, PITTCTRL(base)); +} + +static inline void pit_timer_set_counter(void __iomem *base, unsigned int cnt) +{ + writel(cnt, PITLDVAL(base)); +} + +static inline void pit_timer_irqack(struct pit_timer *pit) +{ + writel(PITTFLG_TIF, PITTFLG(pit->clkevt_base)); +} + +static u64 notrace pit_read_sched_clock(void) +{ + return ~readl(sched_clock_base); +} + +static u64 pit_timer_clocksource_read(struct clocksource *cs) +{ + struct pit_timer *pit = cs_to_pit(cs); + + return (u64)~readl(PITCVAL(pit->clksrc_base)); +} + +static int pit_clocksource_init(struct pit_timer *pit, const char *name, + void __iomem *base, unsigned long rate) +{ + /* + * The channels 0 and 1 can be chained to build a 64-bit + * timer. Let's use the channel 2 as a clocksource and leave + * the channels 0 and 1 unused for anyone else who needs them + */ + pit->clksrc_base = base + PIT_CH(2); + pit->cs.name = name; + pit->cs.rating = 300; + pit->cs.read = pit_timer_clocksource_read; + pit->cs.mask = CLOCKSOURCE_MASK(32); + pit->cs.flags = CLOCK_SOURCE_IS_CONTINUOUS; + + /* set the max load value and start the clock source counter */ + pit_timer_disable(pit->clksrc_base); + pit_timer_set_counter(pit->clksrc_base, ~0); + pit_timer_enable(pit->clksrc_base, 0); + + sched_clock_base = pit->clksrc_base + PITCVAL_OFFSET; + sched_clock_register(pit_read_sched_clock, 32, rate); + + return clocksource_register_hz(&pit->cs, rate); +} + +static int pit_set_next_event(unsigned long delta, struct clock_event_device *ced) +{ + struct pit_timer *pit = ced_to_pit(ced); + + /* + * set a new value to PITLDVAL register will not restart the timer, + * to abort the current cycle and start a timer period with the new + * value, the timer must be disabled and enabled again. + * and the PITLAVAL should be set to delta minus one according to pit + * hardware requirement. + */ + pit_timer_disable(pit->clkevt_base); + pit_timer_set_counter(pit->clkevt_base, delta - 1); + pit_timer_enable(pit->clkevt_base, true); + + return 0; +} + +static int pit_shutdown(struct clock_event_device *ced) +{ + struct pit_timer *pit = ced_to_pit(ced); + + pit_timer_disable(pit->clkevt_base); + + return 0; +} + +static int pit_set_periodic(struct clock_event_device *ced) +{ + struct pit_timer *pit = ced_to_pit(ced); + + pit_set_next_event(pit->rate / HZ, ced); + + return 0; +} + +static irqreturn_t pit_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *ced = dev_id; + struct pit_timer *pit = ced_to_pit(ced); + + pit_timer_irqack(pit); + + /* + * pit hardware doesn't support oneshot, it will generate an interrupt + * and reload the counter value from PITLDVAL when PITCVAL reach zero, + * and start the counter again. So software need to disable the timer + * to stop the counter loop in ONESHOT mode. + */ + if (likely(clockevent_state_oneshot(ced))) + pit_timer_disable(pit->clkevt_base); + + ced->event_handler(ced); + + return IRQ_HANDLED; +} + +static int pit_clockevent_per_cpu_init(struct pit_timer *pit, const char *name, + void __iomem *base, unsigned long rate, + int irq, unsigned int cpu) +{ + int ret; + + /* + * The channels 0 and 1 can be chained to build a 64-bit + * timer. Let's use the channel 3 as a clockevent and leave + * the channels 0 and 1 unused for anyone else who needs them + */ + pit->clkevt_base = base + PIT_CH(3); + pit->rate = rate; + + pit_timer_disable(pit->clkevt_base); + + pit_timer_irqack(pit); + + ret = request_irq(irq, pit_timer_interrupt, IRQF_TIMER | IRQF_NOBALANCING, + name, &pit->ced); + if (ret) + return ret; + + pit->ced.cpumask = cpumask_of(cpu); + pit->ced.irq = irq; + + pit->ced.name = name; + pit->ced.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; + pit->ced.set_state_shutdown = pit_shutdown; + pit->ced.set_state_periodic = pit_set_periodic; + pit->ced.set_next_event = pit_set_next_event; + pit->ced.rating = 300; + + per_cpu(pit_timers, cpu) = pit; + + return 0; +} + +static void pit_clockevent_per_cpu_exit(struct pit_timer *pit, unsigned int cpu) +{ + pit_timer_disable(pit->clkevt_base); + free_irq(pit->ced.irq, &pit->ced); + per_cpu(pit_timers, cpu) = NULL; +} + +static int pit_clockevent_starting_cpu(unsigned int cpu) +{ + struct pit_timer *pit = per_cpu(pit_timers, cpu); + int ret; + + if (!pit) + return 0; + + ret = irq_force_affinity(pit->ced.irq, cpumask_of(cpu)); + if (ret) { + pit_clockevent_per_cpu_exit(pit, cpu); + return ret; + } + + /* + * The value for the LDVAL register trigger is calculated as: + * LDVAL trigger = (period / clock period) - 1 + * The pit is a 32-bit down count timer, when the counter value + * reaches 0, it will generate an interrupt, thus the minimal + * LDVAL trigger value is 1. And then the min_delta is + * minimal LDVAL trigger value + 1, and the max_delta is full 32-bit. + */ + clockevents_config_and_register(&pit->ced, pit->rate, 2, 0xffffffff); + + return 0; +} + +static int pit_timer_init(struct device_node *np) +{ + struct pit_timer *pit; + struct clk *pit_clk; + void __iomem *timer_base; + const char *name = of_node_full_name(np); + unsigned long clk_rate; + int irq, ret; + + pit = kzalloc_obj(*pit); + if (!pit) + return -ENOMEM; + + ret = -ENXIO; + timer_base = of_iomap(np, 0); + if (!timer_base) { + pr_err("Failed to iomap\n"); + goto out_kfree; + } + + ret = -EINVAL; + irq = irq_of_parse_and_map(np, 0); + if (irq <= 0) { + pr_err("Failed to irq_of_parse_and_map\n"); + goto out_iounmap; + } + + pit_clk = of_clk_get(np, 0); + if (IS_ERR(pit_clk)) { + ret = PTR_ERR(pit_clk); + goto out_irq_dispose_mapping; + } + + ret = clk_prepare_enable(pit_clk); + if (ret) + goto out_clk_put; + + clk_rate = clk_get_rate(pit_clk); + + pit_module_disable(timer_base); + + ret = pit_clocksource_init(pit, name, timer_base, clk_rate); + if (ret) { + pr_err("Failed to initialize clocksource '%pOF'\n", np); + goto out_pit_module_disable; + } + + ret = pit_clockevent_per_cpu_init(pit, name, timer_base, clk_rate, irq, pit_instances); + if (ret) { + pr_err("Failed to initialize clockevent '%pOF'\n", np); + goto out_pit_clocksource_unregister; + } + + /* enable the pit module */ + pit_module_enable(timer_base); + + pit_instances++; + + if (pit_instances == max_pit_instances) { + ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "PIT timer:starting", + pit_clockevent_starting_cpu, NULL); + if (ret < 0) { + pit_clockevent_per_cpu_exit(pit, pit_instances); + goto out_pit_clocksource_unregister; + } + } + + return 0; + +out_pit_clocksource_unregister: + clocksource_unregister(&pit->cs); +out_pit_module_disable: + pit_module_disable(timer_base); + clk_disable_unprepare(pit_clk); +out_clk_put: + clk_put(pit_clk); +out_irq_dispose_mapping: + irq_dispose_mapping(irq); +out_iounmap: + iounmap(timer_base); +out_kfree: + kfree(pit); + + return ret; +} + +static int pit_timer_probe(struct platform_device *pdev) +{ + const struct pit_timer_data *pit_timer_data; + + pit_timer_data = of_device_get_match_data(&pdev->dev); + if (pit_timer_data) + max_pit_instances = pit_timer_data->max_pit_instances; + + return pit_timer_init(pdev->dev.of_node); +} + +static struct pit_timer_data s32g2_data = { .max_pit_instances = 2 }; + +static const struct of_device_id pit_timer_of_match[] = { + { .compatible = "nxp,s32g2-pit", .data = &s32g2_data }, + { } +}; +MODULE_DEVICE_TABLE(of, pit_timer_of_match); + +static struct platform_driver nxp_pit_driver = { + .driver = { + .name = "nxp-pit", + .of_match_table = pit_timer_of_match, + .suppress_bind_attrs = true, + }, + .probe = pit_timer_probe, +}; +builtin_platform_driver(nxp_pit_driver); + +TIMER_OF_DECLARE(vf610, "fsl,vf610-pit", pit_timer_init); -- cgit v1.3.1