From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- drivers/powercap/powercap_sys.c | 684 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 684 insertions(+) create mode 100644 drivers/powercap/powercap_sys.c (limited to 'drivers/powercap/powercap_sys.c') diff --git a/drivers/powercap/powercap_sys.c b/drivers/powercap/powercap_sys.c new file mode 100644 index 000000000..9197fa20d --- /dev/null +++ b/drivers/powercap/powercap_sys.c @@ -0,0 +1,684 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Power capping class + * Copyright (c) 2013, Intel Corporation. + */ + +#include +#include +#include +#include +#include +#include + +#define to_powercap_zone(n) container_of(n, struct powercap_zone, dev) +#define to_powercap_control_type(n) \ + container_of(n, struct powercap_control_type, dev) + +/* Power zone show function */ +#define define_power_zone_show(_attr) \ +static ssize_t _attr##_show(struct device *dev, \ + struct device_attribute *dev_attr,\ + char *buf) \ +{ \ + u64 value; \ + ssize_t len = -EINVAL; \ + struct powercap_zone *power_zone = to_powercap_zone(dev); \ + \ + if (power_zone->ops->get_##_attr) { \ + if (!power_zone->ops->get_##_attr(power_zone, &value)) \ + len = sysfs_emit(buf, "%lld\n", value); \ + } \ + \ + return len; \ +} + +/* The only meaningful input is 0 (reset), others are silently ignored */ +#define define_power_zone_store(_attr) \ +static ssize_t _attr##_store(struct device *dev,\ + struct device_attribute *dev_attr, \ + const char *buf, size_t count) \ +{ \ + int err; \ + struct powercap_zone *power_zone = to_powercap_zone(dev); \ + u64 value; \ + \ + err = kstrtoull(buf, 10, &value); \ + if (err) \ + return -EINVAL; \ + if (value) \ + return count; \ + if (power_zone->ops->reset_##_attr) { \ + if (!power_zone->ops->reset_##_attr(power_zone)) \ + return count; \ + } \ + \ + return -EINVAL; \ +} + +/* Power zone constraint show function */ +#define define_power_zone_constraint_show(_attr) \ +static ssize_t show_constraint_##_attr(struct device *dev, \ + struct device_attribute *dev_attr,\ + char *buf) \ +{ \ + u64 value; \ + ssize_t len = -ENODATA; \ + struct powercap_zone *power_zone = to_powercap_zone(dev); \ + int id; \ + struct powercap_zone_constraint *pconst;\ + \ + if (sscanf(dev_attr->attr.name, "constraint_%d_", &id) != 1) \ + return -EINVAL; \ + if (id >= power_zone->const_id_cnt) \ + return -EINVAL; \ + pconst = &power_zone->constraints[id]; \ + if (pconst && pconst->ops && pconst->ops->get_##_attr) { \ + if (!pconst->ops->get_##_attr(power_zone, id, &value)) \ + len = sysfs_emit(buf, "%lld\n", value); \ + } \ + \ + return len; \ +} + +/* Power zone constraint store function */ +#define define_power_zone_constraint_store(_attr) \ +static ssize_t store_constraint_##_attr(struct device *dev,\ + struct device_attribute *dev_attr, \ + const char *buf, size_t count) \ +{ \ + int err; \ + u64 value; \ + struct powercap_zone *power_zone = to_powercap_zone(dev); \ + int id; \ + struct powercap_zone_constraint *pconst;\ + \ + if (sscanf(dev_attr->attr.name, "constraint_%d_", &id) != 1) \ + return -EINVAL; \ + if (id >= power_zone->const_id_cnt) \ + return -EINVAL; \ + pconst = &power_zone->constraints[id]; \ + err = kstrtoull(buf, 10, &value); \ + if (err) \ + return -EINVAL; \ + if (pconst && pconst->ops && pconst->ops->set_##_attr) { \ + if (!pconst->ops->set_##_attr(power_zone, id, value)) \ + return count; \ + } \ + \ + return -ENODATA; \ +} + +/* Power zone information callbacks */ +define_power_zone_show(power_uw); +define_power_zone_show(max_power_range_uw); +define_power_zone_show(energy_uj); +define_power_zone_store(energy_uj); +define_power_zone_show(max_energy_range_uj); + +/* Power zone attributes */ +static DEVICE_ATTR_RO(max_power_range_uw); +static DEVICE_ATTR_RO(power_uw); +static DEVICE_ATTR_RO(max_energy_range_uj); +static DEVICE_ATTR_RW(energy_uj); + +/* Power zone constraint attributes callbacks */ +define_power_zone_constraint_show(power_limit_uw); +define_power_zone_constraint_store(power_limit_uw); +define_power_zone_constraint_show(time_window_us); +define_power_zone_constraint_store(time_window_us); +define_power_zone_constraint_show(max_power_uw); +define_power_zone_constraint_show(min_power_uw); +define_power_zone_constraint_show(max_time_window_us); +define_power_zone_constraint_show(min_time_window_us); + +/* For one time seeding of constraint device attributes */ +struct powercap_constraint_attr { + struct device_attribute power_limit_attr; + struct device_attribute time_window_attr; + struct device_attribute max_power_attr; + struct device_attribute min_power_attr; + struct device_attribute max_time_window_attr; + struct device_attribute min_time_window_attr; + struct device_attribute name_attr; +}; + +static struct powercap_constraint_attr + constraint_attrs[MAX_CONSTRAINTS_PER_ZONE]; + +/* A list of powercap control_types */ +static LIST_HEAD(powercap_cntrl_list); +/* Mutex to protect list of powercap control_types */ +static DEFINE_MUTEX(powercap_cntrl_list_lock); + +#define POWERCAP_CONSTRAINT_NAME_LEN 30 /* Some limit to avoid overflow */ +static ssize_t show_constraint_name(struct device *dev, + struct device_attribute *dev_attr, + char *buf) +{ + const char *name; + struct powercap_zone *power_zone = to_powercap_zone(dev); + int id; + ssize_t len = -ENODATA; + struct powercap_zone_constraint *pconst; + + if (sscanf(dev_attr->attr.name, "constraint_%d_", &id) != 1) + return -EINVAL; + if (id >= power_zone->const_id_cnt) + return -EINVAL; + pconst = &power_zone->constraints[id]; + + if (pconst && pconst->ops && pconst->ops->get_name) { + name = pconst->ops->get_name(power_zone, id); + if (name) { + len = sysfs_emit(buf, "%.*s\n", + POWERCAP_CONSTRAINT_NAME_LEN - 1, name); + } + } + + return len; +} + +static int create_constraint_attribute(int id, const char *name, + int mode, + struct device_attribute *dev_attr, + ssize_t (*show)(struct device *, + struct device_attribute *, char *), + ssize_t (*store)(struct device *, + struct device_attribute *, + const char *, size_t) + ) +{ + + dev_attr->attr.name = kasprintf(GFP_KERNEL, "constraint_%d_%s", + id, name); + if (!dev_attr->attr.name) + return -ENOMEM; + dev_attr->attr.mode = mode; + dev_attr->show = show; + dev_attr->store = store; + + return 0; +} + +static void free_constraint_attributes(void) +{ + int i; + + for (i = 0; i < MAX_CONSTRAINTS_PER_ZONE; ++i) { + kfree(constraint_attrs[i].power_limit_attr.attr.name); + kfree(constraint_attrs[i].time_window_attr.attr.name); + kfree(constraint_attrs[i].name_attr.attr.name); + kfree(constraint_attrs[i].max_power_attr.attr.name); + kfree(constraint_attrs[i].min_power_attr.attr.name); + kfree(constraint_attrs[i].max_time_window_attr.attr.name); + kfree(constraint_attrs[i].min_time_window_attr.attr.name); + } +} + +static int seed_constraint_attributes(void) +{ + int i; + int ret; + + for (i = 0; i < MAX_CONSTRAINTS_PER_ZONE; ++i) { + ret = create_constraint_attribute(i, "power_limit_uw", + S_IWUSR | S_IRUGO, + &constraint_attrs[i].power_limit_attr, + show_constraint_power_limit_uw, + store_constraint_power_limit_uw); + if (ret) + goto err_alloc; + ret = create_constraint_attribute(i, "time_window_us", + S_IWUSR | S_IRUGO, + &constraint_attrs[i].time_window_attr, + show_constraint_time_window_us, + store_constraint_time_window_us); + if (ret) + goto err_alloc; + ret = create_constraint_attribute(i, "name", S_IRUGO, + &constraint_attrs[i].name_attr, + show_constraint_name, + NULL); + if (ret) + goto err_alloc; + ret = create_constraint_attribute(i, "max_power_uw", S_IRUGO, + &constraint_attrs[i].max_power_attr, + show_constraint_max_power_uw, + NULL); + if (ret) + goto err_alloc; + ret = create_constraint_attribute(i, "min_power_uw", S_IRUGO, + &constraint_attrs[i].min_power_attr, + show_constraint_min_power_uw, + NULL); + if (ret) + goto err_alloc; + ret = create_constraint_attribute(i, "max_time_window_us", + S_IRUGO, + &constraint_attrs[i].max_time_window_attr, + show_constraint_max_time_window_us, + NULL); + if (ret) + goto err_alloc; + ret = create_constraint_attribute(i, "min_time_window_us", + S_IRUGO, + &constraint_attrs[i].min_time_window_attr, + show_constraint_min_time_window_us, + NULL); + if (ret) + goto err_alloc; + + } + + return 0; + +err_alloc: + free_constraint_attributes(); + + return ret; +} + +static int create_constraints(struct powercap_zone *power_zone, + int nr_constraints, + const struct powercap_zone_constraint_ops *const_ops) +{ + int i; + int ret = 0; + int count; + struct powercap_zone_constraint *pconst; + + if (!power_zone || !const_ops || !const_ops->get_power_limit_uw || + !const_ops->set_power_limit_uw || + !const_ops->get_time_window_us || + !const_ops->set_time_window_us) + return -EINVAL; + + count = power_zone->zone_attr_count; + for (i = 0; i < nr_constraints; ++i) { + pconst = &power_zone->constraints[i]; + pconst->ops = const_ops; + pconst->id = power_zone->const_id_cnt; + power_zone->const_id_cnt++; + power_zone->zone_dev_attrs[count++] = + &constraint_attrs[i].power_limit_attr.attr; + power_zone->zone_dev_attrs[count++] = + &constraint_attrs[i].time_window_attr.attr; + if (pconst->ops->get_name) + power_zone->zone_dev_attrs[count++] = + &constraint_attrs[i].name_attr.attr; + if (pconst->ops->get_max_power_uw) + power_zone->zone_dev_attrs[count++] = + &constraint_attrs[i].max_power_attr.attr; + if (pconst->ops->get_min_power_uw) + power_zone->zone_dev_attrs[count++] = + &constraint_attrs[i].min_power_attr.attr; + if (pconst->ops->get_max_time_window_us) + power_zone->zone_dev_attrs[count++] = + &constraint_attrs[i].max_time_window_attr.attr; + if (pconst->ops->get_min_time_window_us) + power_zone->zone_dev_attrs[count++] = + &constraint_attrs[i].min_time_window_attr.attr; + } + power_zone->zone_attr_count = count; + + return ret; +} + +static bool control_type_valid(void *control_type) +{ + struct powercap_control_type *pos = NULL; + bool found = false; + + mutex_lock(&powercap_cntrl_list_lock); + + list_for_each_entry(pos, &powercap_cntrl_list, node) { + if (pos == control_type) { + found = true; + break; + } + } + mutex_unlock(&powercap_cntrl_list_lock); + + return found; +} + +static ssize_t name_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct powercap_zone *power_zone = to_powercap_zone(dev); + + return sysfs_emit(buf, "%s\n", power_zone->name); +} + +static DEVICE_ATTR_RO(name); + +/* Create zone and attributes in sysfs */ +static void create_power_zone_common_attributes( + struct powercap_zone *power_zone) +{ + int count = 0; + + power_zone->zone_dev_attrs[count++] = &dev_attr_name.attr; + if (power_zone->ops->get_max_energy_range_uj) + power_zone->zone_dev_attrs[count++] = + &dev_attr_max_energy_range_uj.attr; + if (power_zone->ops->get_energy_uj) { + if (power_zone->ops->reset_energy_uj) + dev_attr_energy_uj.attr.mode = S_IWUSR | S_IRUSR; + else + dev_attr_energy_uj.attr.mode = S_IRUSR; + power_zone->zone_dev_attrs[count++] = + &dev_attr_energy_uj.attr; + } + if (power_zone->ops->get_power_uw) + power_zone->zone_dev_attrs[count++] = + &dev_attr_power_uw.attr; + if (power_zone->ops->get_max_power_range_uw) + power_zone->zone_dev_attrs[count++] = + &dev_attr_max_power_range_uw.attr; + power_zone->zone_dev_attrs[count] = NULL; + power_zone->zone_attr_count = count; +} + +static void powercap_release(struct device *dev) +{ + bool allocated; + + if (dev->parent) { + struct powercap_zone *power_zone = to_powercap_zone(dev); + + /* Store flag as the release() may free memory */ + allocated = power_zone->allocated; + /* Remove id from parent idr struct */ + idr_remove(power_zone->parent_idr, power_zone->id); + /* Destroy idrs allocated for this zone */ + idr_destroy(&power_zone->idr); + kfree(power_zone->name); + kfree(power_zone->zone_dev_attrs); + kfree(power_zone->constraints); + if (power_zone->ops->release) + power_zone->ops->release(power_zone); + if (allocated) + kfree(power_zone); + } else { + struct powercap_control_type *control_type = + to_powercap_control_type(dev); + + /* Store flag as the release() may free memory */ + allocated = control_type->allocated; + idr_destroy(&control_type->idr); + mutex_destroy(&control_type->lock); + if (control_type->ops && control_type->ops->release) + control_type->ops->release(control_type); + if (allocated) + kfree(control_type); + } +} + +static ssize_t enabled_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + bool mode = true; + + /* Default is enabled */ + if (dev->parent) { + struct powercap_zone *power_zone = to_powercap_zone(dev); + if (power_zone->ops->get_enable) + if (power_zone->ops->get_enable(power_zone, &mode)) + mode = false; + } else { + struct powercap_control_type *control_type = + to_powercap_control_type(dev); + if (control_type->ops && control_type->ops->get_enable) + if (control_type->ops->get_enable(control_type, &mode)) + mode = false; + } + + return sysfs_emit(buf, "%d\n", mode); +} + +static ssize_t enabled_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t len) +{ + bool mode; + + if (kstrtobool(buf, &mode)) + return -EINVAL; + if (dev->parent) { + struct powercap_zone *power_zone = to_powercap_zone(dev); + if (power_zone->ops->set_enable) + if (!power_zone->ops->set_enable(power_zone, mode)) + return len; + } else { + struct powercap_control_type *control_type = + to_powercap_control_type(dev); + if (control_type->ops && control_type->ops->set_enable) + if (!control_type->ops->set_enable(control_type, mode)) + return len; + } + + return -ENOSYS; +} + +static DEVICE_ATTR_RW(enabled); + +static struct attribute *powercap_attrs[] = { + &dev_attr_enabled.attr, + NULL, +}; +ATTRIBUTE_GROUPS(powercap); + +static struct class powercap_class = { + .name = "powercap", + .dev_release = powercap_release, + .dev_groups = powercap_groups, +}; + +struct powercap_zone *powercap_register_zone( + struct powercap_zone *power_zone, + struct powercap_control_type *control_type, + const char *name, + struct powercap_zone *parent, + const struct powercap_zone_ops *ops, + int nr_constraints, + const struct powercap_zone_constraint_ops *const_ops) +{ + int result; + int nr_attrs; + + if (!name || !control_type || !ops || + nr_constraints > MAX_CONSTRAINTS_PER_ZONE || + (!ops->get_energy_uj && !ops->get_power_uw) || + !control_type_valid(control_type)) + return ERR_PTR(-EINVAL); + + if (power_zone) { + if (!ops->release) + return ERR_PTR(-EINVAL); + memset(power_zone, 0, sizeof(*power_zone)); + } else { + power_zone = kzalloc_obj(*power_zone); + if (!power_zone) + return ERR_PTR(-ENOMEM); + power_zone->allocated = true; + } + power_zone->ops = ops; + power_zone->control_type_inst = control_type; + if (!parent) { + power_zone->dev.parent = &control_type->dev; + power_zone->parent_idr = &control_type->idr; + } else { + power_zone->dev.parent = &parent->dev; + power_zone->parent_idr = &parent->idr; + } + power_zone->dev.class = &powercap_class; + + mutex_lock(&control_type->lock); + /* Using idr to get the unique id */ + result = idr_alloc(power_zone->parent_idr, NULL, 0, 0, GFP_KERNEL); + if (result < 0) + goto err_idr_alloc; + + power_zone->id = result; + idr_init(&power_zone->idr); + result = -ENOMEM; + power_zone->name = kstrdup(name, GFP_KERNEL); + if (!power_zone->name) + goto err_name_alloc; + power_zone->constraints = kzalloc_objs(*power_zone->constraints, + nr_constraints); + if (!power_zone->constraints) + goto err_const_alloc; + + nr_attrs = nr_constraints * POWERCAP_CONSTRAINTS_ATTRS + + POWERCAP_ZONE_MAX_ATTRS + 1; + power_zone->zone_dev_attrs = kcalloc(nr_attrs, sizeof(void *), + GFP_KERNEL); + if (!power_zone->zone_dev_attrs) + goto err_attr_alloc; + create_power_zone_common_attributes(power_zone); + result = create_constraints(power_zone, nr_constraints, const_ops); + if (result) + goto err_dev_ret; + + power_zone->zone_dev_attrs[power_zone->zone_attr_count] = NULL; + power_zone->dev_zone_attr_group.attrs = power_zone->zone_dev_attrs; + power_zone->dev_attr_groups[0] = &power_zone->dev_zone_attr_group; + power_zone->dev_attr_groups[1] = NULL; + power_zone->dev.groups = power_zone->dev_attr_groups; + dev_set_name(&power_zone->dev, "%s:%x", + dev_name(power_zone->dev.parent), + power_zone->id); + result = device_register(&power_zone->dev); + if (result) { + put_device(&power_zone->dev); + mutex_unlock(&control_type->lock); + + return ERR_PTR(result); + } + + control_type->nr_zones++; + mutex_unlock(&control_type->lock); + + return power_zone; + +err_dev_ret: + kfree(power_zone->zone_dev_attrs); +err_attr_alloc: + kfree(power_zone->constraints); +err_const_alloc: + kfree(power_zone->name); +err_name_alloc: + idr_remove(power_zone->parent_idr, power_zone->id); +err_idr_alloc: + if (power_zone->allocated) + kfree(power_zone); + mutex_unlock(&control_type->lock); + + return ERR_PTR(result); +} +EXPORT_SYMBOL_GPL(powercap_register_zone); + +int powercap_unregister_zone(struct powercap_control_type *control_type, + struct powercap_zone *power_zone) +{ + if (!power_zone || !control_type) + return -EINVAL; + + mutex_lock(&control_type->lock); + control_type->nr_zones--; + mutex_unlock(&control_type->lock); + + device_unregister(&power_zone->dev); + + return 0; +} +EXPORT_SYMBOL_GPL(powercap_unregister_zone); + +struct powercap_control_type *powercap_register_control_type( + struct powercap_control_type *control_type, + const char *name, + const struct powercap_control_type_ops *ops) +{ + int result; + + if (!name) + return ERR_PTR(-EINVAL); + if (control_type) { + if (!ops || !ops->release) + return ERR_PTR(-EINVAL); + memset(control_type, 0, sizeof(*control_type)); + } else { + control_type = kzalloc_obj(*control_type); + if (!control_type) + return ERR_PTR(-ENOMEM); + control_type->allocated = true; + } + mutex_init(&control_type->lock); + control_type->ops = ops; + INIT_LIST_HEAD(&control_type->node); + control_type->dev.class = &powercap_class; + dev_set_name(&control_type->dev, "%s", name); + idr_init(&control_type->idr); + + mutex_lock(&powercap_cntrl_list_lock); + list_add_tail(&control_type->node, &powercap_cntrl_list); + mutex_unlock(&powercap_cntrl_list_lock); + + result = device_register(&control_type->dev); + if (result) { + mutex_lock(&powercap_cntrl_list_lock); + list_del(&control_type->node); + mutex_unlock(&powercap_cntrl_list_lock); + + idr_destroy(&control_type->idr); + put_device(&control_type->dev); + return ERR_PTR(result); + } + + return control_type; +} +EXPORT_SYMBOL_GPL(powercap_register_control_type); + +int powercap_unregister_control_type(struct powercap_control_type *control_type) +{ + struct powercap_control_type *pos = NULL; + + if (control_type->nr_zones) { + dev_err(&control_type->dev, "Zones of this type still not freed\n"); + return -EINVAL; + } + mutex_lock(&powercap_cntrl_list_lock); + list_for_each_entry(pos, &powercap_cntrl_list, node) { + if (pos == control_type) { + list_del(&control_type->node); + mutex_unlock(&powercap_cntrl_list_lock); + device_unregister(&control_type->dev); + return 0; + } + } + mutex_unlock(&powercap_cntrl_list_lock); + + return -ENODEV; +} +EXPORT_SYMBOL_GPL(powercap_unregister_control_type); + +static int __init powercap_init(void) +{ + int result; + + result = seed_constraint_attributes(); + if (result) + return result; + + return class_register(&powercap_class); +} + +fs_initcall(powercap_init); + +MODULE_DESCRIPTION("PowerCap sysfs Driver"); +MODULE_AUTHOR("Srinivas Pandruvada "); -- cgit v1.3.1