From a9e3760b0838299649c0d57cca44daaf40ba3c33 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 14 Sep 2026 22:12:34 -1000 Subject: sched_ext: Maintain an online cid mask in the scheduler arena Schedulers on the default cid mapping treat [0, nr_online_cids) as the online set and restart on hotplug. Schedulers that install their own mapping with scx_bpf_cid_override() have no way to learn which cids are online: the count no longer identifies members and the CPU-form cpumask is unusable from cid programs. This is an obvious hole in the cid API. Add scx_bpf_online_cmask(), a kernel-maintained cmask in the scheduler's arena, allocated alongside the per-CPU scratch masks and populated after the cid mapping is finalized and before ops.init(), for child schedulers too. The pointer stays valid through ops.exit() with no reference to take. It is the arena offset as a void pointer, the same form struct_ops arena arguments arrive in. The verifier types the void return as a scalar for the program's arena cast. The mask follows the SCX hotplug notifications: seeded from cpu_active_mask and updated before ops.cid_online/offline() runs, so it lags cpu_online_mask only inside a hotplug transition. Updates walk the scheduler list under the lock that also serializes unlinking. Reads are live, not atomic snapshots. Root initialization excludes hotplug. v2: Reworded the getter kerneldoc (Andrea Righi). Signed-off-by: Tejun Heo Reviewed-by: Andrea Righi --- drivers/clk/clkdev.c | 418 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 418 insertions(+) create mode 100644 drivers/clk/clkdev.c (limited to 'drivers/clk/clkdev.c') diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c new file mode 100644 index 000000000..abaa0f9e0 --- /dev/null +++ b/drivers/clk/clkdev.c @@ -0,0 +1,418 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * drivers/clk/clkdev.c + * + * Copyright (C) 2008 Russell King. + * + * Helper for the clk API to assist looking up a struct clk. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "clk.h" + +static LIST_HEAD(clocks); +static DEFINE_MUTEX(clocks_mutex); + +/* + * Find the correct struct clk for the device and connection ID. + * We do slightly fuzzy matching here: + * An entry with a NULL ID is assumed to be a wildcard. + * If an entry has a device ID, it must match + * If an entry has a connection ID, it must match + * Then we take the most specific entry - with the following + * order of precedence: dev+con > dev only > con only. + */ +static struct clk_lookup *clk_find(const char *dev_id, const char *con_id) +{ + struct clk_lookup *p, *cl = NULL; + int match, best_found = 0, best_possible = 0; + + if (dev_id) + best_possible += 2; + if (con_id) + best_possible += 1; + + lockdep_assert_held(&clocks_mutex); + + list_for_each_entry(p, &clocks, node) { + match = 0; + if (p->dev_id) { + if (!dev_id || strcmp(p->dev_id, dev_id)) + continue; + match += 2; + } + if (p->con_id) { + if (!con_id || strcmp(p->con_id, con_id)) + continue; + match += 1; + } + + if (match > best_found) { + cl = p; + if (match != best_possible) + best_found = match; + else + break; + } + } + return cl; +} + +struct clk_hw *clk_find_hw(const char *dev_id, const char *con_id) +{ + struct clk_lookup *cl; + struct clk_hw *hw = ERR_PTR(-ENOENT); + + mutex_lock(&clocks_mutex); + cl = clk_find(dev_id, con_id); + if (cl) + hw = cl->clk_hw; + mutex_unlock(&clocks_mutex); + + return hw; +} + +static struct clk *__clk_get_sys(struct device *dev, const char *dev_id, + const char *con_id) +{ + struct clk_hw *hw = clk_find_hw(dev_id, con_id); + + return clk_hw_create_clk(dev, hw, dev_id, con_id); +} + +struct clk *clk_get_sys(const char *dev_id, const char *con_id) +{ + return __clk_get_sys(NULL, dev_id, con_id); +} +EXPORT_SYMBOL(clk_get_sys); + +struct clk *clk_get(struct device *dev, const char *con_id) +{ + const char *dev_id = dev ? dev_name(dev) : NULL; + struct clk_hw *hw; + + if (dev && dev->of_node) { + hw = of_clk_get_hw(dev->of_node, 0, con_id); + if (!IS_ERR(hw) || PTR_ERR(hw) == -EPROBE_DEFER) + return clk_hw_create_clk(dev, hw, dev_id, con_id); + } + + return __clk_get_sys(dev, dev_id, con_id); +} +EXPORT_SYMBOL(clk_get); + +void clk_put(struct clk *clk) +{ + __clk_put(clk); +} +EXPORT_SYMBOL(clk_put); + +static void __clkdev_add(struct clk_lookup *cl) +{ + mutex_lock(&clocks_mutex); + list_add_tail(&cl->node, &clocks); + mutex_unlock(&clocks_mutex); +} + +void clkdev_add(struct clk_lookup *cl) +{ + if (!cl->clk_hw) + cl->clk_hw = __clk_get_hw(cl->clk); + __clkdev_add(cl); +} +EXPORT_SYMBOL(clkdev_add); + +void clkdev_add_table(struct clk_lookup *cl, size_t num) +{ + mutex_lock(&clocks_mutex); + while (num--) { + cl->clk_hw = __clk_get_hw(cl->clk); + list_add_tail(&cl->node, &clocks); + cl++; + } + mutex_unlock(&clocks_mutex); +} + +#define MAX_DEV_ID 24 +#define MAX_CON_ID 16 + +struct clk_lookup_alloc { + struct clk_lookup cl; + char dev_id[MAX_DEV_ID]; + char con_id[MAX_CON_ID]; +}; + +static __printf(3, 0) struct clk_lookup * __ref +vclkdev_alloc(struct clk_hw *hw, const char *con_id, const char *dev_fmt, + va_list ap) +{ + struct clk_lookup_alloc *cla; + struct va_format vaf; + const char *failure; + va_list ap_copy; + size_t max_size; + ssize_t res; + + cla = kzalloc_obj(*cla); + if (!cla) + return NULL; + + va_copy(ap_copy, ap); + + cla->cl.clk_hw = hw; + if (con_id) { + res = strscpy(cla->con_id, con_id, sizeof(cla->con_id)); + if (res < 0) { + max_size = sizeof(cla->con_id); + failure = "connection"; + goto fail; + } + cla->cl.con_id = cla->con_id; + } + + if (dev_fmt) { + res = vsnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap); + if (res >= sizeof(cla->dev_id)) { + max_size = sizeof(cla->dev_id); + failure = "device"; + goto fail; + } + cla->cl.dev_id = cla->dev_id; + } + + va_end(ap_copy); + + return &cla->cl; + +fail: + if (dev_fmt) + vaf.fmt = dev_fmt; + else + vaf.fmt = "null-device"; + vaf.va = &ap_copy; + pr_err("%pV:%s: %s ID is greater than %zu\n", + &vaf, con_id, failure, max_size); + va_end(ap_copy); + + /* + * Don't fail in this case, but as the entry won't ever match just + * fill it with something that also won't match. + */ + strscpy(cla->con_id, "bad", sizeof(cla->con_id)); + strscpy(cla->dev_id, "bad", sizeof(cla->dev_id)); + + return &cla->cl; +} + +static __printf(3, 0) struct clk_lookup * +vclkdev_create(struct clk_hw *hw, const char *con_id, const char *dev_fmt, + va_list ap) +{ + struct clk_lookup *cl; + + cl = vclkdev_alloc(hw, con_id, dev_fmt, ap); + if (cl) + __clkdev_add(cl); + + return cl; +} + +/** + * clkdev_create - allocate and add a clkdev lookup structure + * @clk: struct clk to associate with all clk_lookups + * @con_id: connection ID string on device + * @dev_fmt: format string describing device name + * + * Returns a clk_lookup structure, which can be later unregistered and + * freed. + */ +struct clk_lookup *clkdev_create(struct clk *clk, const char *con_id, + const char *dev_fmt, ...) +{ + struct clk_lookup *cl; + va_list ap; + + va_start(ap, dev_fmt); + cl = vclkdev_create(__clk_get_hw(clk), con_id, dev_fmt, ap); + va_end(ap); + + return cl; +} +EXPORT_SYMBOL_GPL(clkdev_create); + +/** + * clkdev_hw_create - allocate and add a clkdev lookup structure + * @hw: struct clk_hw to associate with all clk_lookups + * @con_id: connection ID string on device + * @dev_fmt: format string describing device name + * + * Returns a clk_lookup structure, which can be later unregistered and + * freed. + */ +struct clk_lookup *clkdev_hw_create(struct clk_hw *hw, const char *con_id, + const char *dev_fmt, ...) +{ + struct clk_lookup *cl; + va_list ap; + + va_start(ap, dev_fmt); + cl = vclkdev_create(hw, con_id, dev_fmt, ap); + va_end(ap); + + return cl; +} +EXPORT_SYMBOL_GPL(clkdev_hw_create); + +int clk_add_alias(const char *alias, const char *alias_dev_name, + const char *con_id, struct device *dev) +{ + struct clk *r = clk_get(dev, con_id); + struct clk_lookup *l; + + if (IS_ERR(r)) + return PTR_ERR(r); + + l = clkdev_create(r, alias, alias_dev_name ? "%s" : NULL, + alias_dev_name); + clk_put(r); + + return l ? 0 : -ENODEV; +} +EXPORT_SYMBOL(clk_add_alias); + +/* + * clkdev_drop - remove a clock dynamically allocated + */ +void clkdev_drop(struct clk_lookup *cl) +{ + mutex_lock(&clocks_mutex); + list_del(&cl->node); + mutex_unlock(&clocks_mutex); + kfree(cl); +} +EXPORT_SYMBOL(clkdev_drop); + +static __printf(3, 4) struct clk_lookup * +__clk_register_clkdev(struct clk_hw *hw, const char *con_id, const char *dev_id, ...) +{ + struct clk_lookup *cl; + va_list ap; + + va_start(ap, dev_id); + cl = vclkdev_create(hw, con_id, dev_id, ap); + va_end(ap); + + return cl; +} + +static int do_clk_register_clkdev(struct clk_hw *hw, + struct clk_lookup **cl, const char *con_id, const char *dev_id) +{ + if (IS_ERR(hw)) + return PTR_ERR(hw); + /* + * Since dev_id can be NULL, and NULL is handled specially, we must + * pass it as either a NULL format string, or with "%s". + */ + if (dev_id) + *cl = __clk_register_clkdev(hw, con_id, "%s", dev_id); + else + *cl = __clk_register_clkdev(hw, con_id, NULL); + + return *cl ? 0 : -ENOMEM; +} + +/** + * clk_register_clkdev - register one clock lookup for a struct clk + * @clk: struct clk to associate with all clk_lookups + * @con_id: connection ID string on device + * @dev_id: string describing device name + * + * con_id or dev_id may be NULL as a wildcard, just as in the rest of + * clkdev. + * + * To make things easier for mass registration, we detect error clks + * from a previous clk_register() call, and return the error code for + * those. This is to permit this function to be called immediately + * after clk_register(). + */ +int clk_register_clkdev(struct clk *clk, const char *con_id, + const char *dev_id) +{ + struct clk_lookup *cl; + + if (IS_ERR(clk)) + return PTR_ERR(clk); + + return do_clk_register_clkdev(__clk_get_hw(clk), &cl, con_id, + dev_id); +} +EXPORT_SYMBOL(clk_register_clkdev); + +/** + * clk_hw_register_clkdev - register one clock lookup for a struct clk_hw + * @hw: struct clk_hw to associate with all clk_lookups + * @con_id: connection ID string on device + * @dev_id: format string describing device name + * + * con_id or dev_id may be NULL as a wildcard, just as in the rest of + * clkdev. + * + * To make things easier for mass registration, we detect error clk_hws + * from a previous clk_hw_register_*() call, and return the error code for + * those. This is to permit this function to be called immediately + * after clk_hw_register_*(). + */ +int clk_hw_register_clkdev(struct clk_hw *hw, const char *con_id, + const char *dev_id) +{ + struct clk_lookup *cl; + + return do_clk_register_clkdev(hw, &cl, con_id, dev_id); +} +EXPORT_SYMBOL(clk_hw_register_clkdev); + +static void devm_clkdev_release(void *res) +{ + clkdev_drop(res); +} + +/** + * devm_clk_hw_register_clkdev - managed clk lookup registration for clk_hw + * @dev: device this lookup is bound + * @hw: struct clk_hw to associate with all clk_lookups + * @con_id: connection ID string on device + * @dev_id: format string describing device name + * + * con_id or dev_id may be NULL as a wildcard, just as in the rest of + * clkdev. + * + * To make things easier for mass registration, we detect error clk_hws + * from a previous clk_hw_register_*() call, and return the error code for + * those. This is to permit this function to be called immediately + * after clk_hw_register_*(). + */ +int devm_clk_hw_register_clkdev(struct device *dev, struct clk_hw *hw, + const char *con_id, const char *dev_id) +{ + struct clk_lookup *cl; + int rval; + + rval = do_clk_register_clkdev(hw, &cl, con_id, dev_id); + if (rval) + return rval; + + return devm_add_action_or_reset(dev, devm_clkdev_release, cl); +} +EXPORT_SYMBOL(devm_clk_hw_register_clkdev); -- cgit v1.3.1