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, 86 insertions, 0 deletions

diff --git a/include/dt-bindings/reset/mt7622-reset.h b/include/dt-bindings/reset/mt7622-reset.h
new file mode 100644
index 000000000..da0d1ae81
--- /dev/null
+++ b/include/dt-bindings/reset/mt7622-reset.h
@@ -0,0 +1,86 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2017 MediaTek Inc.
+ * Author: Sean Wang <sean.wang@mediatek.com>
+ */
+
+#ifndef _DT_BINDINGS_RESET_CONTROLLER_MT7622
+#define _DT_BINDINGS_RESET_CONTROLLER_MT7622
+
+/* INFRACFG resets */
+#define MT7622_INFRA_EMI_REG_RST		0
+#define MT7622_INFRA_DRAMC0_A0_RST		1
+#define MT7622_INFRA_APCIRQ_EINT_RST		3
+#define MT7622_INFRA_APXGPT_RST			4
+#define MT7622_INFRA_SCPSYS_RST			5
+#define MT7622_INFRA_PMIC_WRAP_RST		7
+#define MT7622_INFRA_IRRX_RST			9
+#define MT7622_INFRA_EMI_RST			16
+#define MT7622_INFRA_WED0_RST			17
+#define MT7622_INFRA_DRAMC_RST			18
+#define MT7622_INFRA_CCI_INTF_RST		19
+#define MT7622_INFRA_TRNG_RST			21
+#define MT7622_INFRA_SYSIRQ_RST			22
+#define MT7622_INFRA_WED1_RST			25
+
+/* PERICFG Subsystem resets */
+#define MT7622_PERI_UART0_SW_RST		0
+#define MT7622_PERI_UART1_SW_RST		1
+#define MT7622_PERI_UART2_SW_RST		2
+#define MT7622_PERI_UART3_SW_RST		3
+#define MT7622_PERI_UART4_SW_RST		4
+#define MT7622_PERI_BTIF_SW_RST			6
+#define MT7622_PERI_PWM_SW_RST			8
+#define MT7622_PERI_AUXADC_SW_RST		10
+#define MT7622_PERI_DMA_SW_RST			11
+#define MT7622_PERI_IRTX_SW_RST			13
+#define MT7622_PERI_NFI_SW_RST			14
+#define MT7622_PERI_THERM_SW_RST		16
+#define MT7622_PERI_MSDC0_SW_RST		19
+#define MT7622_PERI_MSDC1_SW_RST		20
+#define MT7622_PERI_I2C0_SW_RST			22
+#define MT7622_PERI_I2C1_SW_RST			23
+#define MT7622_PERI_I2C2_SW_RST			24
+#define MT7622_PERI_SPI0_SW_RST			33
+#define MT7622_PERI_SPI1_SW_RST			34
+#define MT7622_PERI_FLASHIF_SW_RST		36
+
+/* TOPRGU resets */
+#define MT7622_TOPRGU_INFRA_RST			0
+#define MT7622_TOPRGU_ETHDMA_RST		1
+#define MT7622_TOPRGU_DDRPHY_RST		6
+#define MT7622_TOPRGU_INFRA_AO_RST		8
+#define MT7622_TOPRGU_CONN_RST			9
+#define MT7622_TOPRGU_APMIXED_RST		10
+#define MT7622_TOPRGU_CONN_MCU_RST		12
+
+/* PCIe/SATA Subsystem resets */
+#define MT7622_SATA_PHY_REG_RST			12
+#define MT7622_SATA_PHY_SW_RST			13
+#define MT7622_SATA_AXI_BUS_RST			15
+#define MT7622_PCIE1_CORE_RST			19
+#define MT7622_PCIE1_MMIO_RST			20
+#define MT7622_PCIE1_HRST			21
+#define MT7622_PCIE1_USER_RST			22
+#define MT7622_PCIE1_PIPE_RST			23
+#define MT7622_PCIE0_CORE_RST			27
+#define MT7622_PCIE0_MMIO_RST			28
+#define MT7622_PCIE0_HRST			29
+#define MT7622_PCIE0_USER_RST			30
+#define MT7622_PCIE0_PIPE_RST			31
+
+/* SSUSB Subsystem resets */
+#define MT7622_SSUSB_PHY_PWR_RST		3
+#define MT7622_SSUSB_MAC_PWR_RST		4
+
+/* ETHSYS Subsystem resets */
+#define MT7622_ETHSYS_SYS_RST			0
+#define MT7622_ETHSYS_MCM_RST			2
+#define MT7622_ETHSYS_HSDMA_RST			5
+#define MT7622_ETHSYS_FE_RST			6
+#define MT7622_ETHSYS_GMAC_RST			23
+#define MT7622_ETHSYS_EPHY_RST			24
+#define MT7622_ETHSYS_CRYPTO_RST		29
+#define MT7622_ETHSYS_PPE_RST			31
+
+#endif  /* _DT_BINDINGS_RESET_CONTROLLER_MT7622 */