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/of/kobj.c | 165 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 165 insertions(+) create mode 100644 drivers/of/kobj.c (limited to 'drivers/of/kobj.c') diff --git a/drivers/of/kobj.c b/drivers/of/kobj.c new file mode 100644 index 000000000..1bb61a2c3 --- /dev/null +++ b/drivers/of/kobj.c @@ -0,0 +1,165 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include + +#include "of_private.h" + +/* true when node is initialized */ +static int of_node_is_initialized(const struct device_node *node) +{ + return node && node->kobj.state_initialized; +} + +/* true when node is attached (i.e. present on sysfs) */ +int of_node_is_attached(const struct device_node *node) +{ + return node && node->kobj.state_in_sysfs; +} + + +#ifndef CONFIG_OF_DYNAMIC +static void of_node_release(struct kobject *kobj) +{ + /* Without CONFIG_OF_DYNAMIC, no nodes gets freed */ +} +#endif /* CONFIG_OF_DYNAMIC */ + +const struct kobj_type of_node_ktype = { + .release = of_node_release, +}; + +static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj, + const struct bin_attribute *bin_attr, char *buf, + loff_t offset, size_t count) +{ + struct property *pp = container_of(bin_attr, struct property, attr); + return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length); +} + +/* always return newly allocated name, caller must free after use */ +static const char *safe_name(const struct kobject *kobj, const char *orig_name) +{ + const char *name = orig_name; + struct kernfs_node *kn; + int i = 0; + + /* don't be a hero. After 16 tries give up */ + while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) { + sysfs_put(kn); + if (name != orig_name) + kfree(name); + name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i); + } + + if (name == orig_name) { + name = kstrdup(orig_name, GFP_KERNEL); + } else { + pr_warn("Duplicate name in %s, renamed to \"%s\"\n", + kobject_name(kobj), name); + } + return name; +} + +int __of_add_property_sysfs(struct device_node *np, struct property *pp) +{ + int rc; + + /* Important: Don't leak passwords */ + bool secure = strncmp(pp->name, "security-", 9) == 0; + + if (!IS_ENABLED(CONFIG_SYSFS)) + return 0; + + if (!of_kset || !of_node_is_attached(np)) + return 0; + + sysfs_bin_attr_init(&pp->attr); + pp->attr.attr.name = safe_name(&np->kobj, pp->name); + pp->attr.attr.mode = secure ? 0400 : 0444; + pp->attr.size = secure ? 0 : pp->length; + pp->attr.read = of_node_property_read; + + rc = sysfs_create_bin_file(&np->kobj, &pp->attr); + WARN(rc, "error adding attribute %s to node %pOF\n", pp->name, np); + return rc; +} + +void __of_sysfs_remove_bin_file(struct device_node *np, const struct property *prop) +{ + if (!IS_ENABLED(CONFIG_SYSFS)) + return; + + sysfs_remove_bin_file(&np->kobj, &prop->attr); + kfree(prop->attr.attr.name); +} + +void __of_remove_property_sysfs(struct device_node *np, const struct property *prop) +{ + /* at early boot, bail here and defer setup to of_init() */ + if (of_kset && of_node_is_attached(np)) + __of_sysfs_remove_bin_file(np, prop); +} + +void __of_update_property_sysfs(struct device_node *np, struct property *newprop, + const struct property *oldprop) +{ + /* At early boot, bail out and defer setup to of_init() */ + if (!of_kset) + return; + + if (oldprop) + __of_sysfs_remove_bin_file(np, oldprop); + __of_add_property_sysfs(np, newprop); +} + +int __of_attach_node_sysfs(struct device_node *np) +{ + const char *name; + struct kobject *parent; + struct property *pp; + int rc; + + if (!IS_ENABLED(CONFIG_SYSFS) || !of_kset) + return 0; + + np->kobj.kset = of_kset; + if (!np->parent) { + /* Nodes without parents are new top level trees */ + name = safe_name(&of_kset->kobj, "base"); + parent = NULL; + } else { + name = safe_name(&np->parent->kobj, kbasename(np->full_name)); + parent = &np->parent->kobj; + } + if (!name) + return -ENOMEM; + + rc = kobject_add(&np->kobj, parent, "%s", name); + kfree(name); + if (rc) + return rc; + + for_each_property_of_node(np, pp) + __of_add_property_sysfs(np, pp); + + of_node_get(np); + return 0; +} + +void __of_detach_node_sysfs(struct device_node *np) +{ + struct property *pp; + + BUG_ON(!of_node_is_initialized(np)); + if (!of_kset) + return; + + /* only remove properties if on sysfs */ + if (of_node_is_attached(np)) { + for_each_property_of_node(np, pp) + __of_sysfs_remove_bin_file(np, pp); + kobject_del(&np->kobj); + } + + of_node_put(np); +} -- cgit v1.3.1