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/reset/reset-hsdk.c | 135 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 135 insertions(+) create mode 100644 drivers/reset/reset-hsdk.c (limited to 'drivers/reset/reset-hsdk.c') diff --git a/drivers/reset/reset-hsdk.c b/drivers/reset/reset-hsdk.c new file mode 100644 index 000000000..98460e087 --- /dev/null +++ b/drivers/reset/reset-hsdk.c @@ -0,0 +1,135 @@ +/* + * Copyright (C) 2017 Synopsys. + * + * Synopsys HSDK Development platform reset driver. + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define to_hsdk_rst(p) container_of((p), struct hsdk_rst, rcdev) + +struct hsdk_rst { + void __iomem *regs_ctl; + void __iomem *regs_rst; + spinlock_t lock; + struct reset_controller_dev rcdev; +}; + +static const u32 rst_map[] = { + BIT(16), /* APB_RST */ + BIT(17), /* AXI_RST */ + BIT(18), /* ETH_RST */ + BIT(19), /* USB_RST */ + BIT(20), /* SDIO_RST */ + BIT(21), /* HDMI_RST */ + BIT(22), /* GFX_RST */ + BIT(25), /* DMAC_RST */ + BIT(31), /* EBI_RST */ +}; + +#define HSDK_MAX_RESETS ARRAY_SIZE(rst_map) + +#define CGU_SYS_RST_CTRL 0x0 +#define CGU_IP_SW_RESET 0x0 +#define CGU_IP_SW_RESET_DELAY_SHIFT 16 +#define CGU_IP_SW_RESET_DELAY_MASK GENMASK(31, CGU_IP_SW_RESET_DELAY_SHIFT) +#define CGU_IP_SW_RESET_DELAY 0 +#define CGU_IP_SW_RESET_RESET BIT(0) +#define SW_RESET_TIMEOUT 10000 + +static void hsdk_reset_config(struct hsdk_rst *rst, unsigned long id) +{ + writel(rst_map[id], rst->regs_ctl + CGU_SYS_RST_CTRL); +} + +static int hsdk_reset_do(struct hsdk_rst *rst) +{ + u32 reg; + + reg = readl(rst->regs_rst + CGU_IP_SW_RESET); + reg &= ~CGU_IP_SW_RESET_DELAY_MASK; + reg |= CGU_IP_SW_RESET_DELAY << CGU_IP_SW_RESET_DELAY_SHIFT; + reg |= CGU_IP_SW_RESET_RESET; + writel(reg, rst->regs_rst + CGU_IP_SW_RESET); + + /* wait till reset bit is back to 0 */ + return readl_poll_timeout_atomic(rst->regs_rst + CGU_IP_SW_RESET, reg, + !(reg & CGU_IP_SW_RESET_RESET), 5, SW_RESET_TIMEOUT); +} + +static int hsdk_reset_reset(struct reset_controller_dev *rcdev, + unsigned long id) +{ + struct hsdk_rst *rst = to_hsdk_rst(rcdev); + unsigned long flags; + int ret; + + spin_lock_irqsave(&rst->lock, flags); + hsdk_reset_config(rst, id); + ret = hsdk_reset_do(rst); + spin_unlock_irqrestore(&rst->lock, flags); + + return ret; +} + +static const struct reset_control_ops hsdk_reset_ops = { + .reset = hsdk_reset_reset, + .deassert = hsdk_reset_reset, +}; + +static int hsdk_reset_probe(struct platform_device *pdev) +{ + struct hsdk_rst *rst; + + rst = devm_kzalloc(&pdev->dev, sizeof(*rst), GFP_KERNEL); + if (!rst) + return -ENOMEM; + + rst->regs_ctl = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(rst->regs_ctl)) + return PTR_ERR(rst->regs_ctl); + + rst->regs_rst = devm_platform_ioremap_resource(pdev, 1); + if (IS_ERR(rst->regs_rst)) + return PTR_ERR(rst->regs_rst); + + spin_lock_init(&rst->lock); + + rst->rcdev.owner = THIS_MODULE; + rst->rcdev.ops = &hsdk_reset_ops; + rst->rcdev.of_node = pdev->dev.of_node; + rst->rcdev.nr_resets = HSDK_MAX_RESETS; + rst->rcdev.of_reset_n_cells = 1; + + return reset_controller_register(&rst->rcdev); +} + +static const struct of_device_id hsdk_reset_dt_match[] = { + { .compatible = "snps,hsdk-reset" }, + { }, +}; + +static struct platform_driver hsdk_reset_driver = { + .probe = hsdk_reset_probe, + .driver = { + .name = "hsdk-reset", + .of_match_table = hsdk_reset_dt_match, + }, +}; +builtin_platform_driver(hsdk_reset_driver); + +MODULE_AUTHOR("Eugeniy Paltsev "); +MODULE_DESCRIPTION("Synopsys HSDK SDP reset driver"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1