From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- drivers/mfd/syscon.c | 362 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 362 insertions(+) create mode 100644 drivers/mfd/syscon.c (limited to 'drivers/mfd/syscon.c') diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c new file mode 100644 index 000000000..21a7fcdd2 --- /dev/null +++ b/drivers/mfd/syscon.c @@ -0,0 +1,362 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * System Control Driver + * + * Copyright (C) 2012 Freescale Semiconductor, Inc. + * Copyright (C) 2012 Linaro Ltd. + * + * Author: Dong Aisheng + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static DEFINE_MUTEX(syscon_list_lock); +static LIST_HEAD(syscon_list); + +struct syscon { + struct device_node *np; + struct regmap *regmap; + struct reset_control *reset; + struct list_head list; +}; + +static const struct regmap_config syscon_regmap_config = { + .reg_bits = 32, + .val_bits = 32, + .reg_stride = 4, +}; + +static struct syscon *of_syscon_register(struct device_node *np, bool check_res) +{ + struct clk *clk; + struct regmap *regmap; + void __iomem *base; + u32 reg_io_width; + int ret; + struct regmap_config syscon_config = syscon_regmap_config; + struct resource res; + struct reset_control *reset; + resource_size_t res_size; + + WARN_ON(!mutex_is_locked(&syscon_list_lock)); + + struct syscon *syscon __free(kfree) = kzalloc_obj(*syscon); + if (!syscon) + return ERR_PTR(-ENOMEM); + + if (of_address_to_resource(np, 0, &res)) + return ERR_PTR(-ENOMEM); + + base = of_iomap(np, 0); + if (!base) + return ERR_PTR(-ENOMEM); + + /* Parse the device's DT node for an endianness specification */ + if (of_property_read_bool(np, "big-endian")) + syscon_config.val_format_endian = REGMAP_ENDIAN_BIG; + else if (of_property_read_bool(np, "little-endian")) + syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE; + else if (of_property_read_bool(np, "native-endian")) + syscon_config.val_format_endian = REGMAP_ENDIAN_NATIVE; + + /* + * search for reg-io-width property in DT. If it is not provided, + * default to 4 bytes. regmap_init_mmio will return an error if values + * are invalid so there is no need to check them here. + */ + ret = of_property_read_u32(np, "reg-io-width", ®_io_width); + if (ret) + reg_io_width = 4; + + ret = of_hwspin_lock_get_id(np, 0); + if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) { + syscon_config.use_hwlock = true; + syscon_config.hwlock_id = ret; + syscon_config.hwlock_mode = HWLOCK_IRQSTATE; + } else if (ret < 0) { + switch (ret) { + case -ENOENT: + /* Ignore missing hwlock, it's optional. */ + break; + default: + pr_err("Failed to retrieve valid hwlock: %d\n", ret); + fallthrough; + case -EPROBE_DEFER: + goto err_regmap; + } + } + + res_size = resource_size(&res); + if (res_size < reg_io_width) { + ret = -EFAULT; + goto err_regmap; + } + + syscon_config.name = kasprintf(GFP_KERNEL, "%pOFn@%pa", np, &res.start); + if (!syscon_config.name) { + ret = -ENOMEM; + goto err_regmap; + } + syscon_config.reg_stride = reg_io_width; + syscon_config.val_bits = reg_io_width * 8; + syscon_config.max_register = res_size - reg_io_width; + if (!syscon_config.max_register) + syscon_config.max_register_is_0 = true; + + regmap = regmap_init_mmio(NULL, base, &syscon_config); + kfree(syscon_config.name); + if (IS_ERR(regmap)) { + pr_err("regmap init failed\n"); + ret = PTR_ERR(regmap); + goto err_regmap; + } + + if (check_res) { + clk = of_clk_get(np, 0); + if (IS_ERR(clk)) { + ret = PTR_ERR(clk); + /* clock is optional */ + if (ret != -ENOENT) + goto err_clk; + } else { + ret = regmap_mmio_attach_clk(regmap, clk); + if (ret) + goto err_attach_clk; + } + + reset = of_reset_control_get_optional_exclusive(np, NULL); + if (IS_ERR(reset)) { + ret = PTR_ERR(reset); + goto err_attach_clk; + } + + ret = reset_control_deassert(reset); + if (ret) + goto err_reset; + } + + syscon->regmap = regmap; + syscon->np = np; + + list_add_tail(&syscon->list, &syscon_list); + + return_ptr(syscon); + +err_reset: + reset_control_put(reset); +err_attach_clk: + if (!IS_ERR(clk)) + clk_put(clk); +err_clk: + regmap_exit(regmap); +err_regmap: + iounmap(base); + return ERR_PTR(ret); +} + +static struct regmap *device_node_get_regmap(struct device_node *np, + bool create_regmap, + bool check_res) +{ + struct syscon *entry, *syscon = NULL; + + mutex_lock(&syscon_list_lock); + + list_for_each_entry(entry, &syscon_list, list) + if (entry->np == np) { + syscon = entry; + break; + } + + if (!syscon) { + if (create_regmap) + syscon = of_syscon_register(np, check_res); + else + syscon = ERR_PTR(-EPROBE_DEFER); + } + mutex_unlock(&syscon_list_lock); + + if (IS_ERR(syscon)) + return ERR_CAST(syscon); + + return syscon->regmap; +} + +/** + * of_syscon_register_regmap() - Register regmap for specified device node + * @np: Device tree node + * @regmap: Pointer to regmap object + * + * Register an externally created regmap object with syscon for the specified + * device tree node. This regmap will then be returned to client drivers using + * the syscon_regmap_lookup_by_phandle() API. + * + * Return: 0 on success, negative error code on failure. + */ +int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap) +{ + struct syscon *entry, *syscon = NULL; + int ret; + + if (!np || !regmap) + return -EINVAL; + + syscon = kzalloc_obj(*syscon); + if (!syscon) + return -ENOMEM; + + /* check if syscon entry already exists */ + mutex_lock(&syscon_list_lock); + + list_for_each_entry(entry, &syscon_list, list) + if (entry->np == np) { + ret = -EEXIST; + goto err_unlock; + } + + syscon->regmap = regmap; + syscon->np = np; + + /* register the regmap in syscon list */ + list_add_tail(&syscon->list, &syscon_list); + mutex_unlock(&syscon_list_lock); + + return 0; + +err_unlock: + mutex_unlock(&syscon_list_lock); + kfree(syscon); + return ret; +} +EXPORT_SYMBOL_GPL(of_syscon_register_regmap); + +/** + * device_node_to_regmap() - Get or create a regmap for specified device node + * @np: Device tree node + * + * Get a regmap for the specified device node. If there's not an existing + * regmap, then one is instantiated. This function should not be used if the + * device node has a custom regmap driver or has resources (clocks, resets) to + * be managed. Use syscon_node_to_regmap() instead for those cases. + * + * Return: regmap ptr on success, negative error code on failure. + */ +struct regmap *device_node_to_regmap(struct device_node *np) +{ + return device_node_get_regmap(np, true, false); +} +EXPORT_SYMBOL_GPL(device_node_to_regmap); + +/** + * syscon_node_to_regmap() - Get or create a regmap for specified syscon device node + * @np: Device tree node + * + * Get a regmap for the specified device node. If there's not an existing + * regmap, then one is instantiated if the node is a generic "syscon". This + * function is safe to use for a syscon registered with + * of_syscon_register_regmap(). + * + * Return: regmap ptr on success, negative error code on failure. + */ +struct regmap *syscon_node_to_regmap(struct device_node *np) +{ + return device_node_get_regmap(np, of_device_is_compatible(np, "syscon"), true); +} +EXPORT_SYMBOL_GPL(syscon_node_to_regmap); + +struct regmap *syscon_regmap_lookup_by_compatible(const char *s) +{ + struct device_node *syscon_np; + struct regmap *regmap; + + syscon_np = of_find_compatible_node(NULL, NULL, s); + if (!syscon_np) + return ERR_PTR(-ENODEV); + + regmap = syscon_node_to_regmap(syscon_np); + of_node_put(syscon_np); + + return regmap; +} +EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible); + +struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np, + const char *property) +{ + struct device_node *syscon_np; + struct regmap *regmap; + + if (property) + syscon_np = of_parse_phandle(np, property, 0); + else + syscon_np = np; + + if (!syscon_np) + return ERR_PTR(-ENODEV); + + regmap = syscon_node_to_regmap(syscon_np); + + if (property) + of_node_put(syscon_np); + + return regmap; +} +EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle); + +struct regmap *syscon_regmap_lookup_by_phandle_args(struct device_node *np, + const char *property, + int arg_count, + unsigned int *out_args) +{ + struct device_node *syscon_np; + struct of_phandle_args args; + struct regmap *regmap; + unsigned int index; + int rc; + + rc = of_parse_phandle_with_fixed_args(np, property, arg_count, + 0, &args); + if (rc) + return ERR_PTR(rc); + + syscon_np = args.np; + if (!syscon_np) + return ERR_PTR(-ENODEV); + + regmap = syscon_node_to_regmap(syscon_np); + for (index = 0; index < arg_count; index++) + out_args[index] = args.args[index]; + of_node_put(syscon_np); + + return regmap; +} +EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_args); + +/* + * It behaves the same as syscon_regmap_lookup_by_phandle() except where + * there is no regmap phandle. In this case, instead of returning -ENODEV, + * the function returns NULL. + */ +struct regmap *syscon_regmap_lookup_by_phandle_optional(struct device_node *np, + const char *property) +{ + struct regmap *regmap; + + regmap = syscon_regmap_lookup_by_phandle(np, property); + if (IS_ERR(regmap) && PTR_ERR(regmap) == -ENODEV) + return NULL; + + return regmap; +} +EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle_optional); -- cgit v1.3.1