From 4310c6b8e75d6a47f7548e5948fbe6318aa4440a Mon Sep 17 00:00:00 2001 From: Fedor Pchelkin Date: Mon, 31 Aug 2026 10:58:09 +0300 Subject: thunderbolt: Fix NULL dereference in tb_remove_work() There is a slight race between tb_remove_work() and tb_domain_remove() which leads to dereferencing a NULL tb->root_switch pointer inside tb_free_unplugged_xdomains(): Thread A Thread B tb_remove_work() tb_domain_remove() mutex_lock(&tb->lock) tb_stop() /* doesn't cancel a running callback */ cancel_delayed_work(&tcm->remove_work) ... tb_switch_remove(tb->root_switch) tb->root_switch = NULL mutex_unlock(&tb->lock) mutex_lock(&tb->lock) ... /* without checking ->root_switch */ tb_free_unplugged_xdomains(tb->root_switch) mutex_unlock(&tb->lock) Commit a8937f35cf39 ("thunderbolt: Remove XDomain from the bus without holding tb->lock") doesn't seem right to move tb_free_unplugged_xdomains() out of the &tb->lock section and the check for tb->root_switch, in particular. It states: For this reason separate removing the XDomain from the topology data structures (where we need the lock) from unregistering the device from the bus (where remove callbacks of the drivers are being called). tb_free_unplugged_xdomains() belongs to the former group of functions requiring the lock. And it also calls tb_xdomain_remove() which should only be called with &tb->lock held. Found by Linux Verification Center (linuxtesting.org) with Svace static analysis tool. Fixes: a8937f35cf39 ("thunderbolt: Remove XDomain from the bus without holding tb->lock") Cc: stable@vger.kernel.org Signed-off-by: Fedor Pchelkin Signed-off-by: Mika Westerberg --- drivers/clocksource/timer-rda.c | 202 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 202 insertions(+) create mode 100644 drivers/clocksource/timer-rda.c (limited to 'drivers/clocksource/timer-rda.c') diff --git a/drivers/clocksource/timer-rda.c b/drivers/clocksource/timer-rda.c new file mode 100644 index 000000000..0be8e0597 --- /dev/null +++ b/drivers/clocksource/timer-rda.c @@ -0,0 +1,202 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * RDA8810PL SoC timer driver + * + * Copyright RDA Microelectronics Company Limited + * Copyright (c) 2017 Andreas Färber + * Copyright (c) 2018 Manivannan Sadhasivam + * + * RDA8810PL has two independent timers: OSTIMER (56 bit) and HWTIMER (64 bit). + * Each timer provides optional interrupt support. In this driver, OSTIMER is + * used for clockevents and HWTIMER is used for clocksource. + */ + +#include +#include +#include + +#include "timer-of.h" + +#define RDA_OSTIMER_LOADVAL_L 0x000 +#define RDA_OSTIMER_CTRL 0x004 +#define RDA_HWTIMER_LOCKVAL_L 0x024 +#define RDA_HWTIMER_LOCKVAL_H 0x028 +#define RDA_TIMER_IRQ_MASK_SET 0x02c +#define RDA_TIMER_IRQ_MASK_CLR 0x030 +#define RDA_TIMER_IRQ_CLR 0x034 + +#define RDA_OSTIMER_CTRL_ENABLE BIT(24) +#define RDA_OSTIMER_CTRL_REPEAT BIT(28) +#define RDA_OSTIMER_CTRL_LOAD BIT(30) + +#define RDA_TIMER_IRQ_MASK_OSTIMER BIT(0) + +#define RDA_TIMER_IRQ_CLR_OSTIMER BIT(0) + +static int rda_ostimer_start(void __iomem *base, bool periodic, u64 cycles) +{ + u32 ctrl, load_l; + + load_l = (u32)cycles; + ctrl = ((cycles >> 32) & 0xffffff); + ctrl |= RDA_OSTIMER_CTRL_LOAD | RDA_OSTIMER_CTRL_ENABLE; + if (periodic) + ctrl |= RDA_OSTIMER_CTRL_REPEAT; + + /* Enable ostimer interrupt first */ + writel_relaxed(RDA_TIMER_IRQ_MASK_OSTIMER, + base + RDA_TIMER_IRQ_MASK_SET); + + /* Write low 32 bits first, high 24 bits are with ctrl */ + writel_relaxed(load_l, base + RDA_OSTIMER_LOADVAL_L); + writel_relaxed(ctrl, base + RDA_OSTIMER_CTRL); + + return 0; +} + +static int rda_ostimer_stop(void __iomem *base) +{ + /* Disable ostimer interrupt first */ + writel_relaxed(RDA_TIMER_IRQ_MASK_OSTIMER, + base + RDA_TIMER_IRQ_MASK_CLR); + + writel_relaxed(0, base + RDA_OSTIMER_CTRL); + + return 0; +} + +static int rda_ostimer_set_state_shutdown(struct clock_event_device *evt) +{ + struct timer_of *to = to_timer_of(evt); + + rda_ostimer_stop(timer_of_base(to)); + + return 0; +} + +static int rda_ostimer_set_state_oneshot(struct clock_event_device *evt) +{ + struct timer_of *to = to_timer_of(evt); + + rda_ostimer_stop(timer_of_base(to)); + + return 0; +} + +static int rda_ostimer_set_state_periodic(struct clock_event_device *evt) +{ + struct timer_of *to = to_timer_of(evt); + unsigned long cycles_per_jiffy; + + rda_ostimer_stop(timer_of_base(to)); + + cycles_per_jiffy = ((unsigned long long)NSEC_PER_SEC / HZ * + evt->mult) >> evt->shift; + rda_ostimer_start(timer_of_base(to), true, cycles_per_jiffy); + + return 0; +} + +static int rda_ostimer_tick_resume(struct clock_event_device *evt) +{ + return 0; +} + +static int rda_ostimer_set_next_event(unsigned long evt, + struct clock_event_device *ev) +{ + struct timer_of *to = to_timer_of(ev); + + rda_ostimer_start(timer_of_base(to), false, evt); + + return 0; +} + +static irqreturn_t rda_ostimer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + struct timer_of *to = to_timer_of(evt); + + /* clear timer int */ + writel_relaxed(RDA_TIMER_IRQ_CLR_OSTIMER, + timer_of_base(to) + RDA_TIMER_IRQ_CLR); + + if (evt->event_handler) + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static struct timer_of rda_ostimer_of = { + .flags = TIMER_OF_IRQ | TIMER_OF_BASE, + + .clkevt = { + .name = "rda-ostimer", + .rating = 250, + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT | + CLOCK_EVT_FEAT_DYNIRQ, + .set_state_shutdown = rda_ostimer_set_state_shutdown, + .set_state_oneshot = rda_ostimer_set_state_oneshot, + .set_state_periodic = rda_ostimer_set_state_periodic, + .tick_resume = rda_ostimer_tick_resume, + .set_next_event = rda_ostimer_set_next_event, + }, + + .of_base = { + .name = "rda-timer", + .index = 0, + }, + + .of_irq = { + .name = "ostimer", + .handler = rda_ostimer_interrupt, + .flags = IRQF_TIMER, + }, +}; + +static u64 rda_hwtimer_clocksource_read(void) +{ + void __iomem *base = timer_of_base(&rda_ostimer_of); + u32 lo, hi; + + /* Always read low 32 bits first */ + do { + lo = readl_relaxed(base + RDA_HWTIMER_LOCKVAL_L); + hi = readl_relaxed(base + RDA_HWTIMER_LOCKVAL_H); + } while (hi != readl_relaxed(base + RDA_HWTIMER_LOCKVAL_H)); + + return ((u64)hi << 32) | lo; +} + +static u64 rda_hwtimer_read(struct clocksource *cs) +{ + return rda_hwtimer_clocksource_read(); +} + +static struct clocksource rda_hwtimer_clocksource = { + .name = "rda-timer", + .rating = 400, + .read = rda_hwtimer_read, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static int __init rda_timer_init(struct device_node *np) +{ + unsigned long rate = 2000000; + int ret; + + ret = timer_of_init(np, &rda_ostimer_of); + if (ret) + return ret; + + clocksource_register_hz(&rda_hwtimer_clocksource, rate); + sched_clock_register(rda_hwtimer_clocksource_read, 64, rate); + + clockevents_config_and_register(&rda_ostimer_of.clkevt, rate, + 0x2, UINT_MAX); + + return 0; +} + +TIMER_OF_DECLARE(rda8810pl, "rda,8810pl-timer", rda_timer_init); -- cgit v1.3.1