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, 56 insertions, 0 deletions

diff --git a/drivers/crypto/ccp/Kconfig b/drivers/crypto/ccp/Kconfig
new file mode 100644
index 000000000..f16a0f611
--- /dev/null
+++ b/drivers/crypto/ccp/Kconfig
@@ -0,0 +1,56 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config CRYPTO_DEV_CCP_DD
+	tristate "Secure Processor device driver"
+	depends on CPU_SUP_AMD || ARM64
+	default m
+	help
+	  Provides AMD Secure Processor device driver.
+	  If you choose 'M' here, this module will be called ccp.
+
+config CRYPTO_DEV_SP_CCP
+	bool "Cryptographic Coprocessor device"
+	default y
+	depends on CRYPTO_DEV_CCP_DD && DMADEVICES
+	select HW_RANDOM
+	select DMA_ENGINE
+	select CRYPTO_SHA1
+	select CRYPTO_SHA256
+	help
+	  Provides the support for AMD Cryptographic Coprocessor (CCP) device
+	  which can be used to offload encryption operations such as SHA, AES
+	  and more.
+
+config CRYPTO_DEV_CCP_CRYPTO
+	tristate "Encryption and hashing offload support"
+	default m
+	depends on CRYPTO_DEV_CCP_DD
+	depends on CRYPTO_DEV_SP_CCP
+	select CRYPTO_HASH
+	select CRYPTO_SKCIPHER
+	select CRYPTO_AUTHENC
+	select CRYPTO_RSA
+	select CRYPTO_LIB_AES
+	help
+	  Support for using the cryptographic API with the AMD Cryptographic
+	  Coprocessor. This module supports offload of SHA and AES algorithms.
+	  If you choose 'M' here, this module will be called ccp_crypto.
+
+config CRYPTO_DEV_SP_PSP
+	bool "Platform Security Processor (PSP) device"
+	default y
+	depends on CRYPTO_DEV_CCP_DD && X86_64 && AMD_IOMMU
+	select PCI_TSM if PCI
+	help
+	 Provide support for the AMD Platform Security Processor (PSP).
+	 The PSP is a dedicated processor that provides support for key
+	 management commands in Secure Encrypted Virtualization (SEV) mode,
+	 along with software-based Trusted Execution Environment (TEE) to
+	 enable third-party trusted applications.
+
+config CRYPTO_DEV_CCP_DEBUGFS
+	bool "Enable CCP Internals in DebugFS"
+	default n
+	depends on CRYPTO_DEV_SP_CCP
+	help
+	  Expose CCP device information such as operation statistics, feature
+	  information, and descriptor queue contents.