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/soc/tegra/flowctrl.c | 226 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 226 insertions(+) create mode 100644 drivers/soc/tegra/flowctrl.c (limited to 'drivers/soc/tegra/flowctrl.c') diff --git a/drivers/soc/tegra/flowctrl.c b/drivers/soc/tegra/flowctrl.c new file mode 100644 index 000000000..221202db3 --- /dev/null +++ b/drivers/soc/tegra/flowctrl.c @@ -0,0 +1,226 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * drivers/soc/tegra/flowctrl.c + * + * Functions and macros to control the flowcontroller + * + * Copyright (c) 2010-2012, NVIDIA Corporation. All rights reserved. + */ + +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include + +static u8 flowctrl_offset_halt_cpu[] = { + FLOW_CTRL_HALT_CPU0_EVENTS, + FLOW_CTRL_HALT_CPU1_EVENTS, + FLOW_CTRL_HALT_CPU1_EVENTS + 8, + FLOW_CTRL_HALT_CPU1_EVENTS + 16, +}; + +static u8 flowctrl_offset_cpu_csr[] = { + FLOW_CTRL_CPU0_CSR, + FLOW_CTRL_CPU1_CSR, + FLOW_CTRL_CPU1_CSR + 8, + FLOW_CTRL_CPU1_CSR + 16, +}; + +static void __iomem *tegra_flowctrl_base; + +static void flowctrl_update(u8 offset, u32 value) +{ + if (WARN_ONCE(IS_ERR_OR_NULL(tegra_flowctrl_base), + "Tegra flowctrl not initialised!\n")) + return; + + writel(value, tegra_flowctrl_base + offset); + + /* ensure the update has reached the flow controller */ + wmb(); + readl_relaxed(tegra_flowctrl_base + offset); +} + +u32 flowctrl_read_cpu_csr(unsigned int cpuid) +{ + u8 offset = flowctrl_offset_cpu_csr[cpuid]; + + if (WARN_ONCE(IS_ERR_OR_NULL(tegra_flowctrl_base), + "Tegra flowctrl not initialised!\n")) + return 0; + + return readl(tegra_flowctrl_base + offset); +} + +void flowctrl_write_cpu_csr(unsigned int cpuid, u32 value) +{ + return flowctrl_update(flowctrl_offset_cpu_csr[cpuid], value); +} + +void flowctrl_write_cpu_halt(unsigned int cpuid, u32 value) +{ + return flowctrl_update(flowctrl_offset_halt_cpu[cpuid], value); +} + +void flowctrl_cpu_suspend_enter(unsigned int cpuid) +{ + unsigned int reg; + int i; + + reg = flowctrl_read_cpu_csr(cpuid); + switch (tegra_get_chip_id()) { + case TEGRA20: + /* clear wfe bitmap */ + reg &= ~TEGRA20_FLOW_CTRL_CSR_WFE_BITMAP; + /* clear wfi bitmap */ + reg &= ~TEGRA20_FLOW_CTRL_CSR_WFI_BITMAP; + /* pwr gating on wfe */ + reg |= TEGRA20_FLOW_CTRL_CSR_WFE_CPU0 << cpuid; + break; + case TEGRA30: + case TEGRA114: + case TEGRA124: + /* clear wfe bitmap */ + reg &= ~TEGRA30_FLOW_CTRL_CSR_WFE_BITMAP; + /* clear wfi bitmap */ + reg &= ~TEGRA30_FLOW_CTRL_CSR_WFI_BITMAP; + + if (tegra_get_chip_id() == TEGRA30) { + /* + * The wfi doesn't work well on Tegra30 because + * CPU hangs under some odd circumstances after + * power-gating (like memory running off PLLP), + * hence use wfe that is working perfectly fine. + * Note that Tegra30 TRM doc clearly stands that + * wfi should be used for the "Cluster Switching", + * while wfe for the power-gating, just like it + * is done on Tegra20. + */ + reg |= TEGRA20_FLOW_CTRL_CSR_WFE_CPU0 << cpuid; + } else { + /* pwr gating on wfi */ + reg |= TEGRA30_FLOW_CTRL_CSR_WFI_CPU0 << cpuid; + } + break; + } + reg |= FLOW_CTRL_CSR_INTR_FLAG; /* clear intr flag */ + reg |= FLOW_CTRL_CSR_EVENT_FLAG; /* clear event flag */ + reg |= FLOW_CTRL_CSR_ENABLE; /* pwr gating */ + flowctrl_write_cpu_csr(cpuid, reg); + + for (i = 0; i < num_possible_cpus(); i++) { + if (i == cpuid) + continue; + reg = flowctrl_read_cpu_csr(i); + reg |= FLOW_CTRL_CSR_EVENT_FLAG; + reg |= FLOW_CTRL_CSR_INTR_FLAG; + flowctrl_write_cpu_csr(i, reg); + } +} + +void flowctrl_cpu_suspend_exit(unsigned int cpuid) +{ + unsigned int reg; + + /* Disable powergating via flow controller for CPU0 */ + reg = flowctrl_read_cpu_csr(cpuid); + switch (tegra_get_chip_id()) { + case TEGRA20: + /* clear wfe bitmap */ + reg &= ~TEGRA20_FLOW_CTRL_CSR_WFE_BITMAP; + /* clear wfi bitmap */ + reg &= ~TEGRA20_FLOW_CTRL_CSR_WFI_BITMAP; + break; + case TEGRA30: + case TEGRA114: + case TEGRA124: + /* clear wfe bitmap */ + reg &= ~TEGRA30_FLOW_CTRL_CSR_WFE_BITMAP; + /* clear wfi bitmap */ + reg &= ~TEGRA30_FLOW_CTRL_CSR_WFI_BITMAP; + break; + } + reg &= ~FLOW_CTRL_CSR_ENABLE; /* clear enable */ + reg |= FLOW_CTRL_CSR_INTR_FLAG; /* clear intr */ + reg |= FLOW_CTRL_CSR_EVENT_FLAG; /* clear event */ + flowctrl_write_cpu_csr(cpuid, reg); +} + +static int tegra_flowctrl_probe(struct platform_device *pdev) +{ + void __iomem *base = tegra_flowctrl_base; + + tegra_flowctrl_base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL); + if (IS_ERR(tegra_flowctrl_base)) + return PTR_ERR(tegra_flowctrl_base); + + iounmap(base); + + return 0; +} + +static const struct of_device_id tegra_flowctrl_match[] = { + { .compatible = "nvidia,tegra210-flowctrl" }, + { .compatible = "nvidia,tegra124-flowctrl" }, + { .compatible = "nvidia,tegra114-flowctrl" }, + { .compatible = "nvidia,tegra30-flowctrl" }, + { .compatible = "nvidia,tegra20-flowctrl" }, + { } +}; + +static struct platform_driver tegra_flowctrl_driver = { + .driver = { + .name = "tegra-flowctrl", + .suppress_bind_attrs = true, + .of_match_table = tegra_flowctrl_match, + }, + .probe = tegra_flowctrl_probe, +}; +builtin_platform_driver(tegra_flowctrl_driver); + +static int __init tegra_flowctrl_init(void) +{ + struct resource res; + struct device_node *np; + + if (!soc_is_tegra()) + return 0; + + np = of_find_matching_node(NULL, tegra_flowctrl_match); + if (np) { + if (of_address_to_resource(np, 0, &res) < 0) { + pr_err("failed to get flowctrl register\n"); + return -ENXIO; + } + of_node_put(np); + } else if (IS_ENABLED(CONFIG_ARM)) { + /* + * Hardcoded fallback for 32-bit Tegra + * devices if device tree node is missing. + */ + res.start = 0x60007000; + res.end = 0x60007fff; + res.flags = IORESOURCE_MEM; + } else { + /* + * At this point we're running on a Tegra, + * that doesn't support the flow controller + * (eg. Tegra186), so just return. + */ + return 0; + } + + tegra_flowctrl_base = ioremap(res.start, resource_size(&res)); + if (!tegra_flowctrl_base) + return -ENXIO; + + return 0; +} +early_initcall(tegra_flowctrl_init); -- cgit v1.3.1