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/qcom/qcom-pbs.c | 228 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 228 insertions(+) create mode 100644 drivers/soc/qcom/qcom-pbs.c (limited to 'drivers/soc/qcom/qcom-pbs.c') diff --git a/drivers/soc/qcom/qcom-pbs.c b/drivers/soc/qcom/qcom-pbs.c new file mode 100644 index 000000000..06b4a596e --- /dev/null +++ b/drivers/soc/qcom/qcom-pbs.c @@ -0,0 +1,228 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights reserved. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define PBS_CLIENT_TRIG_CTL 0x42 +#define PBS_CLIENT_SW_TRIG_BIT BIT(7) +#define PBS_CLIENT_SCRATCH1 0x50 +#define PBS_CLIENT_SCRATCH2 0x51 +#define PBS_CLIENT_SCRATCH2_ERROR 0xFF + +#define RETRIES 2000 +#define DELAY 1100 + +struct pbs_dev { + struct device *dev; + struct regmap *regmap; + struct mutex lock; + struct device_link *link; + + u32 base; +}; + +static int qcom_pbs_wait_for_ack(struct pbs_dev *pbs, u8 bit_pos) +{ + unsigned int val; + int ret; + + ret = regmap_read_poll_timeout(pbs->regmap, pbs->base + PBS_CLIENT_SCRATCH2, + val, val & BIT(bit_pos), DELAY, DELAY * RETRIES); + + if (ret < 0) { + dev_err(pbs->dev, "Timeout for PBS ACK/NACK for bit %u\n", bit_pos); + return -ETIMEDOUT; + } + + if (val == PBS_CLIENT_SCRATCH2_ERROR) { + ret = regmap_write(pbs->regmap, pbs->base + PBS_CLIENT_SCRATCH2, 0); + dev_err(pbs->dev, "NACK from PBS for bit %u\n", bit_pos); + return -EINVAL; + } + + dev_dbg(pbs->dev, "PBS sequence for bit %u executed!\n", bit_pos); + return 0; +} + +/** + * qcom_pbs_trigger_event() - Trigger the PBS RAM sequence + * @pbs: Pointer to PBS device + * @bitmap: bitmap + * + * This function is used to trigger the PBS RAM sequence to be + * executed by the client driver. + * + * The PBS trigger sequence involves + * 1. setting the PBS sequence bit in PBS_CLIENT_SCRATCH1 + * 2. Initiating the SW PBS trigger + * 3. Checking the equivalent bit in PBS_CLIENT_SCRATCH2 for the + * completion of the sequence. + * 4. If PBS_CLIENT_SCRATCH2 == 0xFF, the PBS sequence failed to execute + * + * Return: 0 on success, < 0 on failure + */ +int qcom_pbs_trigger_event(struct pbs_dev *pbs, u8 bitmap) +{ + unsigned int val; + u16 bit_pos; + int ret; + + if (WARN_ON(!bitmap)) + return -EINVAL; + + if (IS_ERR_OR_NULL(pbs)) + return -EINVAL; + + guard(mutex)(&pbs->lock); + ret = regmap_read(pbs->regmap, pbs->base + PBS_CLIENT_SCRATCH2, &val); + if (ret < 0) + return ret; + + if (val == PBS_CLIENT_SCRATCH2_ERROR) { + /* PBS error - clear SCRATCH2 register */ + ret = regmap_write(pbs->regmap, pbs->base + PBS_CLIENT_SCRATCH2, 0); + if (ret < 0) + return ret; + } + + for (bit_pos = 0; bit_pos < 8; bit_pos++) { + if (!(bitmap & BIT(bit_pos))) + continue; + + /* Clear the PBS sequence bit position */ + ret = regmap_update_bits(pbs->regmap, pbs->base + PBS_CLIENT_SCRATCH2, + BIT(bit_pos), 0); + if (ret < 0) + break; + + /* Set the PBS sequence bit position */ + ret = regmap_update_bits(pbs->regmap, pbs->base + PBS_CLIENT_SCRATCH1, + BIT(bit_pos), BIT(bit_pos)); + if (ret < 0) + break; + + /* Initiate the SW trigger */ + ret = regmap_update_bits(pbs->regmap, pbs->base + PBS_CLIENT_TRIG_CTL, + PBS_CLIENT_SW_TRIG_BIT, PBS_CLIENT_SW_TRIG_BIT); + if (ret < 0) + break; + + ret = qcom_pbs_wait_for_ack(pbs, bit_pos); + if (ret < 0) + break; + + /* Clear the PBS sequence bit position */ + regmap_update_bits(pbs->regmap, pbs->base + PBS_CLIENT_SCRATCH1, BIT(bit_pos), 0); + regmap_update_bits(pbs->regmap, pbs->base + PBS_CLIENT_SCRATCH2, BIT(bit_pos), 0); + } + + /* Clear all the requested bitmap */ + return regmap_update_bits(pbs->regmap, pbs->base + PBS_CLIENT_SCRATCH1, bitmap, 0); +} +EXPORT_SYMBOL_GPL(qcom_pbs_trigger_event); + +/** + * get_pbs_client_device() - Get the PBS device used by client + * @dev: Client device + * + * This function is used to get the PBS device that is being + * used by the client. + * + * Return: pbs_dev on success, ERR_PTR on failure + */ +struct pbs_dev *get_pbs_client_device(struct device *dev) +{ + struct platform_device *pdev; + struct pbs_dev *pbs; + + struct device_node *pbs_dev_node __free(device_node) = of_parse_phandle(dev->of_node, + "qcom,pbs", 0); + if (!pbs_dev_node) { + dev_err(dev, "Missing qcom,pbs property\n"); + return ERR_PTR(-ENODEV); + } + + pdev = of_find_device_by_node(pbs_dev_node); + if (!pdev) { + dev_err(dev, "Unable to find PBS dev_node\n"); + return ERR_PTR(-EPROBE_DEFER); + } + + pbs = platform_get_drvdata(pdev); + if (!pbs) { + dev_err(dev, "Cannot get pbs instance from %s\n", dev_name(&pdev->dev)); + platform_device_put(pdev); + return ERR_PTR(-EPROBE_DEFER); + } + + pbs->link = device_link_add(dev, &pdev->dev, DL_FLAG_AUTOREMOVE_SUPPLIER); + if (!pbs->link) { + dev_err(&pdev->dev, "Failed to create device link to consumer %s\n", dev_name(dev)); + platform_device_put(pdev); + return ERR_PTR(-EINVAL); + } + + platform_device_put(pdev); + + return pbs; +} +EXPORT_SYMBOL_GPL(get_pbs_client_device); + +static int qcom_pbs_probe(struct platform_device *pdev) +{ + struct pbs_dev *pbs; + u32 val; + int ret; + + pbs = devm_kzalloc(&pdev->dev, sizeof(*pbs), GFP_KERNEL); + if (!pbs) + return -ENOMEM; + + pbs->dev = &pdev->dev; + pbs->regmap = dev_get_regmap(pbs->dev->parent, NULL); + if (!pbs->regmap) { + dev_err(pbs->dev, "Couldn't get parent's regmap\n"); + return -EINVAL; + } + + ret = device_property_read_u32(pbs->dev, "reg", &val); + if (ret < 0) { + dev_err(pbs->dev, "Couldn't find reg, ret = %d\n", ret); + return ret; + } + pbs->base = val; + mutex_init(&pbs->lock); + + platform_set_drvdata(pdev, pbs); + + return 0; +} + +static const struct of_device_id qcom_pbs_match_table[] = { + { .compatible = "qcom,pbs" }, + {} +}; +MODULE_DEVICE_TABLE(of, qcom_pbs_match_table); + +static struct platform_driver qcom_pbs_driver = { + .driver = { + .name = "qcom-pbs", + .of_match_table = qcom_pbs_match_table, + }, + .probe = qcom_pbs_probe, +}; +module_platform_driver(qcom_pbs_driver) + +MODULE_DESCRIPTION("QCOM PBS DRIVER"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1