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, 111 insertions, 0 deletions

diff --git a/include/dt-bindings/clock/bcm-sr.h b/include/dt-bindings/clock/bcm-sr.h
new file mode 100644
index 000000000..419011ba1
--- /dev/null
+++ b/include/dt-bindings/clock/bcm-sr.h
@@ -0,0 +1,111 @@
+/*
+ *  BSD LICENSE
+ *
+ *  Copyright(c) 2017 Broadcom. All rights reserved.
+ *
+ *  Redistribution and use in source and binary forms, with or without
+ *  modification, are permitted provided that the following conditions
+ *  are met:
+ *
+ *    * Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *    * Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in
+ *      the documentation and/or other materials provided with the
+ *      distribution.
+ *    * Neither the name of Broadcom Corporation nor the names of its
+ *      contributors may be used to endorse or promote products derived
+ *      from this software without specific prior written permission.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _CLOCK_BCM_SR_H
+#define _CLOCK_BCM_SR_H
+
+/* GENPLL 0 clock channel ID SCR HSLS FS PCIE */
+#define BCM_SR_GENPLL0			0
+#define BCM_SR_GENPLL0_125M_CLK		1
+#define BCM_SR_GENPLL0_SCR_CLK		2
+#define BCM_SR_GENPLL0_250M_CLK		3
+#define BCM_SR_GENPLL0_PCIE_AXI_CLK	4
+#define BCM_SR_GENPLL0_PAXC_AXI_X2_CLK	5
+#define BCM_SR_GENPLL0_PAXC_AXI_CLK	6
+
+/* GENPLL 1 clock channel ID MHB PCIE NITRO */
+#define BCM_SR_GENPLL1			0
+#define BCM_SR_GENPLL1_PCIE_TL_CLK	1
+#define BCM_SR_GENPLL1_MHB_APB_CLK	2
+
+/* GENPLL 2 clock channel ID NITRO MHB*/
+#define BCM_SR_GENPLL2			0
+#define BCM_SR_GENPLL2_NIC_CLK		1
+#define BCM_SR_GENPLL2_TS_500_CLK	2
+#define BCM_SR_GENPLL2_125_NITRO_CLK	3
+#define BCM_SR_GENPLL2_CHIMP_CLK	4
+#define BCM_SR_GENPLL2_NIC_FLASH_CLK	5
+#define BCM_SR_GENPLL2_FS4_CLK		6
+
+/* GENPLL 3 HSLS clock channel ID */
+#define BCM_SR_GENPLL3			0
+#define BCM_SR_GENPLL3_HSLS_CLK		1
+#define BCM_SR_GENPLL3_SDIO_CLK		2
+
+/* GENPLL 4 SCR clock channel ID */
+#define BCM_SR_GENPLL4			0
+#define BCM_SR_GENPLL4_CCN_CLK		1
+#define BCM_SR_GENPLL4_TPIU_PLL_CLK	2
+#define BCM_SR_GENPLL4_NOC_CLK		3
+#define BCM_SR_GENPLL4_CHCLK_FS4_CLK	4
+#define BCM_SR_GENPLL4_BRIDGE_FSCPU_CLK	5
+
+/* GENPLL 5 FS4 clock channel ID */
+#define BCM_SR_GENPLL5			0
+#define BCM_SR_GENPLL5_FS4_HF_CLK	1
+#define BCM_SR_GENPLL5_CRYPTO_AE_CLK	2
+#define BCM_SR_GENPLL5_RAID_AE_CLK	3
+
+/* GENPLL 6 NITRO clock channel ID */
+#define BCM_SR_GENPLL6			0
+#define BCM_SR_GENPLL6_48_USB_CLK	1
+
+/* LCPLL0  clock channel ID */
+#define BCM_SR_LCPLL0			0
+#define BCM_SR_LCPLL0_SATA_REFP_CLK	1
+#define BCM_SR_LCPLL0_SATA_REFN_CLK	2
+#define BCM_SR_LCPLL0_SATA_350_CLK	3
+#define BCM_SR_LCPLL0_SATA_500_CLK	4
+
+/* LCPLL1  clock channel ID */
+#define BCM_SR_LCPLL1			0
+#define BCM_SR_LCPLL1_WAN_CLK		1
+#define BCM_SR_LCPLL1_USB_REF_CLK	2
+#define BCM_SR_LCPLL1_CRMU_TS_CLK	3
+
+/* LCPLL PCIE  clock channel ID */
+#define BCM_SR_LCPLL_PCIE		0
+#define BCM_SR_LCPLL_PCIE_PHY_REF_CLK	1
+
+/* GENPLL EMEM0 clock channel ID */
+#define BCM_SR_EMEMPLL0			0
+#define BCM_SR_EMEMPLL0_EMEM_CLK	1
+
+/* GENPLL EMEM0 clock channel ID */
+#define BCM_SR_EMEMPLL1			0
+#define BCM_SR_EMEMPLL1_EMEM_CLK	1
+
+/* GENPLL EMEM0 clock channel ID */
+#define BCM_SR_EMEMPLL2			0
+#define BCM_SR_EMEMPLL2_EMEM_CLK	1
+
+#endif /* _CLOCK_BCM_SR_H */