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, 281 insertions, 0 deletions

diff --git a/include/pcmcia/device_id.h b/include/pcmcia/device_id.h
new file mode 100644
index 000000000..52b9f5eda
--- /dev/null
+++ b/include/pcmcia/device_id.h
@@ -0,0 +1,281 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * device_id.h -- PCMCIA driver matching helpers
+ *
+ * (C) 2003 - 2004	David Woodhouse
+ * (C) 2003 - 2004	Dominik Brodowski
+ */
+
+#ifndef _LINUX_PCMCIA_DEVICE_ID_H
+#define _LINUX_PCMCIA_DEVICE_ID_H
+
+#ifdef __KERNEL__
+
+#define PCMCIA_DEVICE_MANF_CARD(manf, card) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_MANF_ID| \
+			PCMCIA_DEV_ID_MATCH_CARD_ID, \
+	.manf_id = (manf), \
+	.card_id = (card), }
+
+#define PCMCIA_DEVICE_FUNC_ID(func) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_FUNC_ID, \
+	.func_id = (func), }
+
+#define PCMCIA_DEVICE_PROD_ID1(v1, vh1) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID1, \
+	.prod_id = { (v1), NULL, NULL, NULL }, \
+	.prod_id_hash = { (vh1), 0, 0, 0 }, }
+
+#define PCMCIA_DEVICE_PROD_ID2(v2, vh2) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID2, \
+	.prod_id = { NULL, (v2), NULL, NULL },  \
+	.prod_id_hash = { 0, (vh2), 0, 0 }, }
+
+#define PCMCIA_DEVICE_PROD_ID3(v3, vh3) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID3, \
+	.prod_id = { NULL, NULL, (v3), NULL },  \
+	.prod_id_hash = { 0, 0, (vh3), 0 }, }
+
+#define PCMCIA_DEVICE_PROD_ID12(v1, v2, vh1, vh2) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID2, \
+	.prod_id = { (v1), (v2), NULL, NULL }, \
+	.prod_id_hash = { (vh1), (vh2), 0, 0 }, }
+
+#define PCMCIA_DEVICE_PROD_ID13(v1, v3, vh1, vh3) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID3, \
+	.prod_id = { (v1), NULL, (v3), NULL }, \
+	.prod_id_hash = { (vh1), 0, (vh3), 0 }, }
+
+#define PCMCIA_DEVICE_PROD_ID14(v1, v4, vh1, vh4) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID4, \
+	.prod_id = { (v1), NULL, NULL, (v4) }, \
+	.prod_id_hash = { (vh1), 0, 0, (vh4) }, }
+
+#define PCMCIA_DEVICE_PROD_ID123(v1, v2, v3, vh1, vh2, vh3) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID2| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID3, \
+	.prod_id = { (v1), (v2), (v3), NULL },\
+	.prod_id_hash = { (vh1), (vh2), (vh3), 0 }, }
+
+#define PCMCIA_DEVICE_PROD_ID124(v1, v2, v4, vh1, vh2, vh4) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID2| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID4, \
+	.prod_id = { (v1), (v2), NULL, (v4) }, \
+	.prod_id_hash = { (vh1), (vh2), 0, (vh4) }, }
+
+#define PCMCIA_DEVICE_PROD_ID134(v1, v3, v4, vh1, vh3, vh4) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID3| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID4, \
+	.prod_id = { (v1), NULL, (v3), (v4) }, \
+	.prod_id_hash = { (vh1), 0, (vh3), (vh4) }, }
+
+#define PCMCIA_DEVICE_PROD_ID1234(v1, v2, v3, v4, vh1, vh2, vh3, vh4) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID2| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID3| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID4, \
+	.prod_id = { (v1), (v2), (v3), (v4) }, \
+	.prod_id_hash = { (vh1), (vh2), (vh3), (vh4) }, }
+
+#define PCMCIA_DEVICE_MANF_CARD_PROD_ID1(manf, card, v1, vh1) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_MANF_ID| \
+			PCMCIA_DEV_ID_MATCH_CARD_ID| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID1, \
+	.manf_id = (manf), \
+	.card_id = (card), \
+	.prod_id = { (v1), NULL, NULL, NULL }, \
+	.prod_id_hash = { (vh1), 0, 0, 0 }, }
+
+#define PCMCIA_DEVICE_MANF_CARD_PROD_ID3(manf, card, v3, vh3) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_MANF_ID| \
+			PCMCIA_DEV_ID_MATCH_CARD_ID| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID3, \
+	.manf_id = (manf), \
+	.card_id = (card), \
+	.prod_id = { NULL, NULL, (v3), NULL }, \
+	.prod_id_hash = { 0, 0, (vh3), 0 }, }
+
+
+/* multi-function devices */
+
+#define PCMCIA_MFC_DEVICE_MANF_CARD(mfc, manf, card) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_MANF_ID| \
+			PCMCIA_DEV_ID_MATCH_CARD_ID| \
+			PCMCIA_DEV_ID_MATCH_FUNCTION, \
+	.manf_id = (manf), \
+	.card_id = (card), \
+	.function = (mfc), }
+
+#define PCMCIA_MFC_DEVICE_PROD_ID1(mfc, v1, vh1) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_FUNCTION, \
+	.prod_id = { (v1), NULL, NULL, NULL }, \
+	.prod_id_hash = { (vh1), 0, 0, 0 }, \
+	.function = (mfc), }
+
+#define PCMCIA_MFC_DEVICE_PROD_ID2(mfc, v2, vh2) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID2| \
+			PCMCIA_DEV_ID_MATCH_FUNCTION, \
+	.prod_id = { NULL, (v2), NULL, NULL },  \
+	.prod_id_hash = { 0, (vh2), 0, 0 }, \
+	.function = (mfc), }
+
+#define PCMCIA_MFC_DEVICE_PROD_ID12(mfc, v1, v2, vh1, vh2) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID2| \
+			PCMCIA_DEV_ID_MATCH_FUNCTION, \
+	.prod_id = { (v1), (v2), NULL, NULL }, \
+	.prod_id_hash = { (vh1), (vh2), 0, 0 }, \
+	.function = (mfc), }
+
+#define PCMCIA_MFC_DEVICE_PROD_ID13(mfc, v1, v3, vh1, vh3) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID3| \
+			PCMCIA_DEV_ID_MATCH_FUNCTION, \
+	.prod_id = { (v1), NULL, (v3), NULL }, \
+	.prod_id_hash = { (vh1), 0, (vh3), 0 }, \
+	.function = (mfc), }
+
+#define PCMCIA_MFC_DEVICE_PROD_ID123(mfc, v1, v2, v3, vh1, vh2, vh3) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID2| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID3| \
+			PCMCIA_DEV_ID_MATCH_FUNCTION, \
+	.prod_id = { (v1), (v2), (v3), NULL },\
+	.prod_id_hash = { (vh1), (vh2), (vh3), 0 }, \
+	.function = (mfc), }
+
+/* pseudo multi-function devices */
+
+#define PCMCIA_PFC_DEVICE_MANF_CARD(mfc, manf, card) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_MANF_ID| \
+			PCMCIA_DEV_ID_MATCH_CARD_ID| \
+			PCMCIA_DEV_ID_MATCH_DEVICE_NO, \
+	.manf_id = (manf), \
+	.card_id = (card), \
+	.device_no = (mfc), }
+
+#define PCMCIA_PFC_DEVICE_PROD_ID1(mfc, v1, vh1) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_DEVICE_NO, \
+	.prod_id = { (v1), NULL, NULL, NULL }, \
+	.prod_id_hash = { (vh1), 0, 0, 0 }, \
+	.device_no = (mfc), }
+
+#define PCMCIA_PFC_DEVICE_PROD_ID2(mfc, v2, vh2) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID2| \
+			PCMCIA_DEV_ID_MATCH_DEVICE_NO, \
+	.prod_id = { NULL, (v2), NULL, NULL },  \
+	.prod_id_hash = { 0, (vh2), 0, 0 }, \
+	.device_no = (mfc), }
+
+#define PCMCIA_PFC_DEVICE_PROD_ID12(mfc, v1, v2, vh1, vh2) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID2| \
+			PCMCIA_DEV_ID_MATCH_DEVICE_NO, \
+	.prod_id = { (v1), (v2), NULL, NULL }, \
+	.prod_id_hash = { (vh1), (vh2), 0, 0 }, \
+	.device_no = (mfc), }
+
+#define PCMCIA_PFC_DEVICE_PROD_ID13(mfc, v1, v3, vh1, vh3) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID3| \
+			PCMCIA_DEV_ID_MATCH_DEVICE_NO, \
+	.prod_id = { (v1), NULL, (v3), NULL }, \
+	.prod_id_hash = { (vh1), 0, (vh3), 0 }, \
+	.device_no = (mfc), }
+
+#define PCMCIA_PFC_DEVICE_PROD_ID123(mfc, v1, v2, v3, vh1, vh2, vh3) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID2| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID3| \
+			PCMCIA_DEV_ID_MATCH_DEVICE_NO, \
+	.prod_id = { (v1), (v2), (v3), NULL },\
+	.prod_id_hash = { (vh1), (vh2), (vh3), 0 }, \
+	.device_no = (mfc), }
+
+/* cards needing a CIS override */
+
+#define PCMCIA_DEVICE_CIS_MANF_CARD(manf, card, _cisfile) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_FAKE_CIS | \
+			PCMCIA_DEV_ID_MATCH_MANF_ID| \
+			PCMCIA_DEV_ID_MATCH_CARD_ID, \
+	.manf_id = (manf), \
+	.card_id = (card), \
+	.cisfile = (_cisfile)}
+
+#define PCMCIA_DEVICE_CIS_PROD_ID12(v1, v2, vh1, vh2, _cisfile) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_FAKE_CIS | \
+			PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID2, \
+	.prod_id = { (v1), (v2), NULL, NULL }, \
+	.prod_id_hash = { (vh1), (vh2), 0, 0 }, \
+	.cisfile = (_cisfile)}
+
+#define PCMCIA_DEVICE_CIS_PROD_ID123(v1, v2, v3, vh1, vh2, vh3, _cisfile) { \
+	.match_flags = PCMCIA_DEV_ID_MATCH_FAKE_CIS | \
+			PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID2| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID3, \
+	.prod_id = { (v1), (v2), (v3), NULL },\
+	.prod_id_hash = { (vh1), (vh2), (vh3), 0 }, \
+	.cisfile = (_cisfile)}
+
+
+#define PCMCIA_DEVICE_CIS_PROD_ID2(v2, vh2, _cisfile) { \
+	.match_flags =  PCMCIA_DEV_ID_MATCH_FAKE_CIS | \
+			PCMCIA_DEV_ID_MATCH_PROD_ID2, \
+	.prod_id = { NULL, (v2), NULL, NULL },  \
+	.prod_id_hash = { 0, (vh2), 0, 0 }, \
+	.cisfile = (_cisfile)}
+
+#define PCMCIA_PFC_DEVICE_CIS_PROD_ID12(mfc, v1, v2, vh1, vh2, _cisfile) { \
+	.match_flags =  PCMCIA_DEV_ID_MATCH_FAKE_CIS | \
+			PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID2| \
+			PCMCIA_DEV_ID_MATCH_DEVICE_NO, \
+	.prod_id = { (v1), (v2), NULL, NULL }, \
+	.prod_id_hash = { (vh1), (vh2), 0, 0 },\
+	.device_no = (mfc), \
+	.cisfile = (_cisfile)}
+
+#define PCMCIA_MFC_DEVICE_CIS_MANF_CARD(mfc, manf, card, _cisfile) { \
+	.match_flags =  PCMCIA_DEV_ID_MATCH_FAKE_CIS | \
+			PCMCIA_DEV_ID_MATCH_MANF_ID| \
+			PCMCIA_DEV_ID_MATCH_CARD_ID| \
+			PCMCIA_DEV_ID_MATCH_FUNCTION, \
+	.manf_id = (manf), \
+	.card_id = (card), \
+	.function = (mfc), \
+	.cisfile = (_cisfile)}
+
+#define PCMCIA_MFC_DEVICE_CIS_PROD_ID12(mfc, v1, v2, vh1, vh2, _cisfile) { \
+	.match_flags =  PCMCIA_DEV_ID_MATCH_FAKE_CIS | \
+			PCMCIA_DEV_ID_MATCH_PROD_ID1| \
+			PCMCIA_DEV_ID_MATCH_PROD_ID2| \
+			PCMCIA_DEV_ID_MATCH_FUNCTION, \
+	.prod_id = { (v1), (v2), NULL, NULL }, \
+	.prod_id_hash = { (vh1), (vh2), 0, 0 }, \
+	.function = (mfc), \
+	.cisfile = (_cisfile)}
+
+#define PCMCIA_MFC_DEVICE_CIS_PROD_ID4(mfc, v4, vh4, _cisfile) { \
+	.match_flags =  PCMCIA_DEV_ID_MATCH_FAKE_CIS | \
+			PCMCIA_DEV_ID_MATCH_PROD_ID4| \
+			PCMCIA_DEV_ID_MATCH_FUNCTION, \
+	.prod_id = { NULL, NULL, NULL, (v4) }, \
+	.prod_id_hash = { 0, 0, 0, (vh4) }, \
+	.function = (mfc), \
+	.cisfile = (_cisfile)}
+
+
+#define PCMCIA_DEVICE_NULL { .match_flags = 0, }
+
+#endif /* __KERNEL__ */
+#endif /* _LINUX_PCMCIA_DEVICE_ID_H */