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 --- include/net/seg6.h | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 94 insertions(+) create mode 100644 include/net/seg6.h (limited to 'include/net/seg6.h') diff --git a/include/net/seg6.h b/include/net/seg6.h new file mode 100644 index 000000000..82b3fbbcb --- /dev/null +++ b/include/net/seg6.h @@ -0,0 +1,94 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * SR-IPv6 implementation + * + * Author: + * David Lebrun + */ + +#ifndef _NET_SEG6_H +#define _NET_SEG6_H + +#include +#include +#include +#include + +static inline void update_csum_diff4(struct sk_buff *skb, __be32 from, + __be32 to) +{ + __be32 diff[] = { ~from, to }; + + skb->csum = ~csum_partial((char *)diff, sizeof(diff), ~skb->csum); +} + +static inline void update_csum_diff16(struct sk_buff *skb, __be32 *from, + __be32 *to) +{ + __be32 diff[] = { + ~from[0], ~from[1], ~from[2], ~from[3], + to[0], to[1], to[2], to[3], + }; + + skb->csum = ~csum_partial((char *)diff, sizeof(diff), ~skb->csum); +} + +struct seg6_pernet_data { + struct mutex lock; + struct in6_addr __rcu *tun_src; +#ifdef CONFIG_IPV6_SEG6_HMAC + struct rhashtable hmac_infos; +#endif +}; + +static inline struct seg6_pernet_data *seg6_pernet(struct net *net) +{ +#if IS_ENABLED(CONFIG_IPV6) + return net->ipv6.seg6_data; +#else + return NULL; +#endif +} + +extern int seg6_init(void); +extern void seg6_exit(void); +#ifdef CONFIG_IPV6_SEG6_LWTUNNEL +extern int seg6_iptunnel_init(void); +extern void seg6_iptunnel_exit(void); +extern int seg6_local_init(void); +extern void seg6_local_exit(void); +#else +static inline int seg6_iptunnel_init(void) { return 0; } +static inline void seg6_iptunnel_exit(void) {} +static inline int seg6_local_init(void) { return 0; } +static inline void seg6_local_exit(void) {} +#endif + +extern bool seg6_validate_srh(struct ipv6_sr_hdr *srh, int len, bool reduced); +extern struct ipv6_sr_hdr *seg6_get_srh(struct sk_buff *skb, int flags); +extern void seg6_icmp_srh(struct sk_buff *skb, struct inet6_skb_parm *opt); +extern int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, + int proto); +extern int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh); +extern int seg6_lookup_nexthop(struct sk_buff *skb, struct in6_addr *nhaddr, + u32 tbl_id); + +/* If the packet which invoked an ICMP error contains an SRH return + * the true destination address from within the SRH, otherwise use the + * destination address in the IP header. + */ +static inline const struct in6_addr *seg6_get_daddr(struct sk_buff *skb, + struct inet6_skb_parm *opt) +{ + struct ipv6_sr_hdr *srh; + + if (opt->flags & IP6SKB_SEG6) { + srh = (struct ipv6_sr_hdr *)(skb->data + opt->srhoff); + return &srh->segments[0]; + } + + return NULL; +} + + +#endif -- cgit v1.3.1