kbuild: rust: keep Rust objects out of Clang LTO with inline helpersgrafted

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 <gary@garyguo.net>
Cc: Boqun Feng <boqun@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Matthew Maurer <mmaurer@google.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust")
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 152 insertions, 0 deletions

diff --git a/net/devlink/netlink_gen.h b/net/devlink/netlink_gen.h
new file mode 100644
index 000000000..20034b092
--- /dev/null
+++ b/net/devlink/netlink_gen.h
@@ -0,0 +1,152 @@
+/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */
+/* Do not edit directly, auto-generated from: */
+/*	Documentation/netlink/specs/devlink.yaml */
+/* YNL-GEN kernel header */
+/* To regenerate run: tools/net/ynl/ynl-regen.sh */
+
+#ifndef _LINUX_DEVLINK_GEN_H
+#define _LINUX_DEVLINK_GEN_H
+
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include <uapi/linux/devlink.h>
+
+/* Common nested types */
+extern const struct nla_policy devlink_dl_port_function_nl_policy[DEVLINK_PORT_FN_ATTR_CAPS + 1];
+extern const struct nla_policy devlink_dl_rate_tc_bws_nl_policy[DEVLINK_RATE_TC_ATTR_BW + 1];
+extern const struct nla_policy devlink_dl_selftest_id_nl_policy[DEVLINK_ATTR_SELFTEST_ID_FLASH + 1];
+
+/* Ops table for devlink */
+extern const struct genl_split_ops devlink_nl_ops[75];
+
+int devlink_nl_pre_doit(const struct genl_split_ops *ops, struct sk_buff *skb,
+			struct genl_info *info);
+int devlink_nl_pre_doit_port(const struct genl_split_ops *ops,
+			     struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_pre_doit_port_optional(const struct genl_split_ops *ops,
+				      struct sk_buff *skb,
+				      struct genl_info *info);
+int devlink_nl_pre_doit_dev_lock(const struct genl_split_ops *ops,
+				 struct sk_buff *skb, struct genl_info *info);
+void
+devlink_nl_post_doit(const struct genl_split_ops *ops, struct sk_buff *skb,
+		     struct genl_info *info);
+void
+devlink_nl_post_doit_dev_lock(const struct genl_split_ops *ops,
+			      struct sk_buff *skb, struct genl_info *info);
+
+int devlink_nl_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb);
+int devlink_nl_port_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_port_get_dumpit(struct sk_buff *skb,
+			       struct netlink_callback *cb);
+int devlink_nl_port_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_port_new_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_port_del_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_port_split_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_port_unsplit_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_sb_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_sb_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb);
+int devlink_nl_sb_pool_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_sb_pool_get_dumpit(struct sk_buff *skb,
+				  struct netlink_callback *cb);
+int devlink_nl_sb_pool_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_sb_port_pool_get_doit(struct sk_buff *skb,
+				     struct genl_info *info);
+int devlink_nl_sb_port_pool_get_dumpit(struct sk_buff *skb,
+				       struct netlink_callback *cb);
+int devlink_nl_sb_port_pool_set_doit(struct sk_buff *skb,
+				     struct genl_info *info);
+int devlink_nl_sb_tc_pool_bind_get_doit(struct sk_buff *skb,
+					struct genl_info *info);
+int devlink_nl_sb_tc_pool_bind_get_dumpit(struct sk_buff *skb,
+					  struct netlink_callback *cb);
+int devlink_nl_sb_tc_pool_bind_set_doit(struct sk_buff *skb,
+					struct genl_info *info);
+int devlink_nl_sb_occ_snapshot_doit(struct sk_buff *skb,
+				    struct genl_info *info);
+int devlink_nl_sb_occ_max_clear_doit(struct sk_buff *skb,
+				     struct genl_info *info);
+int devlink_nl_eswitch_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_eswitch_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_dpipe_table_get_doit(struct sk_buff *skb,
+				    struct genl_info *info);
+int devlink_nl_dpipe_entries_get_doit(struct sk_buff *skb,
+				      struct genl_info *info);
+int devlink_nl_dpipe_headers_get_doit(struct sk_buff *skb,
+				      struct genl_info *info);
+int devlink_nl_dpipe_table_counters_set_doit(struct sk_buff *skb,
+					     struct genl_info *info);
+int devlink_nl_resource_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_resource_dump_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_resource_dump_dumpit(struct sk_buff *skb,
+				    struct netlink_callback *cb);
+int devlink_nl_reload_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_param_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_param_get_dumpit(struct sk_buff *skb,
+				struct netlink_callback *cb);
+int devlink_nl_param_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_region_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_region_get_dumpit(struct sk_buff *skb,
+				 struct netlink_callback *cb);
+int devlink_nl_region_new_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_region_del_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_region_read_dumpit(struct sk_buff *skb,
+				  struct netlink_callback *cb);
+int devlink_nl_port_param_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_port_param_get_dumpit(struct sk_buff *skb,
+				     struct netlink_callback *cb);
+int devlink_nl_port_param_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_info_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_info_get_dumpit(struct sk_buff *skb,
+			       struct netlink_callback *cb);
+int devlink_nl_health_reporter_get_doit(struct sk_buff *skb,
+					struct genl_info *info);
+int devlink_nl_health_reporter_get_dumpit(struct sk_buff *skb,
+					  struct netlink_callback *cb);
+int devlink_nl_health_reporter_set_doit(struct sk_buff *skb,
+					struct genl_info *info);
+int devlink_nl_health_reporter_recover_doit(struct sk_buff *skb,
+					    struct genl_info *info);
+int devlink_nl_health_reporter_diagnose_doit(struct sk_buff *skb,
+					     struct genl_info *info);
+int devlink_nl_health_reporter_dump_get_dumpit(struct sk_buff *skb,
+					       struct netlink_callback *cb);
+int devlink_nl_health_reporter_dump_clear_doit(struct sk_buff *skb,
+					       struct genl_info *info);
+int devlink_nl_flash_update_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_trap_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_trap_get_dumpit(struct sk_buff *skb,
+			       struct netlink_callback *cb);
+int devlink_nl_trap_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_trap_group_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_trap_group_get_dumpit(struct sk_buff *skb,
+				     struct netlink_callback *cb);
+int devlink_nl_trap_group_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_trap_policer_get_doit(struct sk_buff *skb,
+				     struct genl_info *info);
+int devlink_nl_trap_policer_get_dumpit(struct sk_buff *skb,
+				       struct netlink_callback *cb);
+int devlink_nl_trap_policer_set_doit(struct sk_buff *skb,
+				     struct genl_info *info);
+int devlink_nl_health_reporter_test_doit(struct sk_buff *skb,
+					 struct genl_info *info);
+int devlink_nl_rate_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_rate_get_dumpit(struct sk_buff *skb,
+			       struct netlink_callback *cb);
+int devlink_nl_rate_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_rate_new_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_rate_del_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_linecard_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_linecard_get_dumpit(struct sk_buff *skb,
+				   struct netlink_callback *cb);
+int devlink_nl_linecard_set_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_selftests_get_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_selftests_get_dumpit(struct sk_buff *skb,
+				    struct netlink_callback *cb);
+int devlink_nl_selftests_run_doit(struct sk_buff *skb, struct genl_info *info);
+int devlink_nl_notify_filter_set_doit(struct sk_buff *skb,
+				      struct genl_info *info);
+
+#endif /* _LINUX_DEVLINK_GEN_H */