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 --- arch/mips/bcm63xx/timer.c | 206 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 206 insertions(+) create mode 100644 arch/mips/bcm63xx/timer.c (limited to 'arch/mips/bcm63xx/timer.c') diff --git a/arch/mips/bcm63xx/timer.c b/arch/mips/bcm63xx/timer.c new file mode 100644 index 000000000..74b83807d --- /dev/null +++ b/arch/mips/bcm63xx/timer.c @@ -0,0 +1,206 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2008 Maxime Bizon + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static DEFINE_RAW_SPINLOCK(timer_reg_lock); +static DEFINE_RAW_SPINLOCK(timer_data_lock); +static struct clk *periph_clk; + +static struct timer_data { + void (*cb)(void *); + void *data; +} timer_data[BCM63XX_TIMER_COUNT]; + +static irqreturn_t timer_interrupt(int irq, void *dev_id) +{ + u32 stat; + int i; + + raw_spin_lock(&timer_reg_lock); + stat = bcm_timer_readl(TIMER_IRQSTAT_REG); + bcm_timer_writel(stat, TIMER_IRQSTAT_REG); + raw_spin_unlock(&timer_reg_lock); + + for (i = 0; i < BCM63XX_TIMER_COUNT; i++) { + if (!(stat & TIMER_IRQSTAT_TIMER_CAUSE(i))) + continue; + + raw_spin_lock(&timer_data_lock); + if (!timer_data[i].cb) { + raw_spin_unlock(&timer_data_lock); + continue; + } + + timer_data[i].cb(timer_data[i].data); + raw_spin_unlock(&timer_data_lock); + } + + return IRQ_HANDLED; +} + +int bcm63xx_timer_enable(int id) +{ + u32 reg; + unsigned long flags; + + if (id >= BCM63XX_TIMER_COUNT) + return -EINVAL; + + raw_spin_lock_irqsave(&timer_reg_lock, flags); + + reg = bcm_timer_readl(TIMER_CTLx_REG(id)); + reg |= TIMER_CTL_ENABLE_MASK; + bcm_timer_writel(reg, TIMER_CTLx_REG(id)); + + reg = bcm_timer_readl(TIMER_IRQSTAT_REG); + reg |= TIMER_IRQSTAT_TIMER_IR_EN(id); + bcm_timer_writel(reg, TIMER_IRQSTAT_REG); + + raw_spin_unlock_irqrestore(&timer_reg_lock, flags); + return 0; +} + +EXPORT_SYMBOL(bcm63xx_timer_enable); + +int bcm63xx_timer_disable(int id) +{ + u32 reg; + unsigned long flags; + + if (id >= BCM63XX_TIMER_COUNT) + return -EINVAL; + + raw_spin_lock_irqsave(&timer_reg_lock, flags); + + reg = bcm_timer_readl(TIMER_CTLx_REG(id)); + reg &= ~TIMER_CTL_ENABLE_MASK; + bcm_timer_writel(reg, TIMER_CTLx_REG(id)); + + reg = bcm_timer_readl(TIMER_IRQSTAT_REG); + reg &= ~TIMER_IRQSTAT_TIMER_IR_EN(id); + bcm_timer_writel(reg, TIMER_IRQSTAT_REG); + + raw_spin_unlock_irqrestore(&timer_reg_lock, flags); + return 0; +} + +EXPORT_SYMBOL(bcm63xx_timer_disable); + +int bcm63xx_timer_register(int id, void (*callback)(void *data), void *data) +{ + unsigned long flags; + int ret; + + if (id >= BCM63XX_TIMER_COUNT || !callback) + return -EINVAL; + + ret = 0; + raw_spin_lock_irqsave(&timer_data_lock, flags); + if (timer_data[id].cb) { + ret = -EBUSY; + goto out; + } + + timer_data[id].cb = callback; + timer_data[id].data = data; + +out: + raw_spin_unlock_irqrestore(&timer_data_lock, flags); + return ret; +} + +EXPORT_SYMBOL(bcm63xx_timer_register); + +void bcm63xx_timer_unregister(int id) +{ + unsigned long flags; + + if (id >= BCM63XX_TIMER_COUNT) + return; + + raw_spin_lock_irqsave(&timer_data_lock, flags); + timer_data[id].cb = NULL; + raw_spin_unlock_irqrestore(&timer_data_lock, flags); +} + +EXPORT_SYMBOL(bcm63xx_timer_unregister); + +unsigned int bcm63xx_timer_countdown(unsigned int countdown_us) +{ + return (clk_get_rate(periph_clk) / (1000 * 1000)) * countdown_us; +} + +EXPORT_SYMBOL(bcm63xx_timer_countdown); + +int bcm63xx_timer_set(int id, int monotonic, unsigned int countdown_us) +{ + u32 reg, countdown; + unsigned long flags; + + if (id >= BCM63XX_TIMER_COUNT) + return -EINVAL; + + countdown = bcm63xx_timer_countdown(countdown_us); + if (countdown & ~TIMER_CTL_COUNTDOWN_MASK) + return -EINVAL; + + raw_spin_lock_irqsave(&timer_reg_lock, flags); + reg = bcm_timer_readl(TIMER_CTLx_REG(id)); + + if (monotonic) + reg &= ~TIMER_CTL_MONOTONIC_MASK; + else + reg |= TIMER_CTL_MONOTONIC_MASK; + + reg &= ~TIMER_CTL_COUNTDOWN_MASK; + reg |= countdown; + bcm_timer_writel(reg, TIMER_CTLx_REG(id)); + + raw_spin_unlock_irqrestore(&timer_reg_lock, flags); + return 0; +} + +EXPORT_SYMBOL(bcm63xx_timer_set); + +static int bcm63xx_timer_init(void) +{ + int ret, irq; + u32 reg; + + reg = bcm_timer_readl(TIMER_IRQSTAT_REG); + reg &= ~TIMER_IRQSTAT_TIMER0_IR_EN; + reg &= ~TIMER_IRQSTAT_TIMER1_IR_EN; + reg &= ~TIMER_IRQSTAT_TIMER2_IR_EN; + bcm_timer_writel(reg, TIMER_IRQSTAT_REG); + + periph_clk = clk_get(NULL, "periph"); + if (IS_ERR(periph_clk)) + return -ENODEV; + + irq = bcm63xx_get_irq_number(IRQ_TIMER); + ret = request_irq(irq, timer_interrupt, 0, "bcm63xx_timer", NULL); + if (ret) { + pr_err("%s: failed to register irq\n", __func__); + return ret; + } + + return 0; +} + +arch_initcall(bcm63xx_timer_init); -- cgit v1.3.1