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, 57 insertions, 0 deletions

diff --git a/drivers/crypto/aspeed/Kconfig b/drivers/crypto/aspeed/Kconfig
new file mode 100644
index 000000000..e93f2f82b
--- /dev/null
+++ b/drivers/crypto/aspeed/Kconfig
@@ -0,0 +1,57 @@
+config CRYPTO_DEV_ASPEED
+	tristate "Support for Aspeed cryptographic engine driver"
+	depends on ARCH_ASPEED || COMPILE_TEST
+	select CRYPTO_ENGINE
+	help
+	  Hash and Crypto Engine (HACE) is designed to accelerate the
+	  throughput of hash data digest, encryption and decryption.
+
+	  Select y here to have support for the cryptographic driver
+	  available on Aspeed SoC.
+
+config CRYPTO_DEV_ASPEED_DEBUG
+	bool "Enable Aspeed crypto debug messages"
+	depends on CRYPTO_DEV_ASPEED
+	help
+	  Print Aspeed crypto debugging messages if you use this
+	  option to ask for those messages.
+	  Avoid enabling this option for production build to
+	  minimize driver timing.
+
+config CRYPTO_DEV_ASPEED_HACE_HASH
+	bool "Enable Aspeed Hash & Crypto Engine (HACE) hash"
+	depends on CRYPTO_DEV_ASPEED
+	select CRYPTO_SHA1
+	select CRYPTO_SHA256
+	select CRYPTO_SHA512
+	select CRYPTO_HMAC
+	help
+	  Select here to enable Aspeed Hash & Crypto Engine (HACE)
+	  hash driver.
+	  Supports multiple message digest standards, including
+	  SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, and so on.
+
+config CRYPTO_DEV_ASPEED_HACE_CRYPTO
+	bool "Enable Aspeed Hash & Crypto Engine (HACE) crypto"
+	depends on CRYPTO_DEV_ASPEED
+	select CRYPTO_AES
+	select CRYPTO_DES
+	select CRYPTO_ECB
+	select CRYPTO_CBC
+	select CRYPTO_CTR
+	help
+	  Select here to enable Aspeed Hash & Crypto Engine (HACE)
+	  crypto driver.
+	  Supports AES/DES symmetric-key encryption and decryption
+	  with ECB/CBC/CTR options.
+
+config CRYPTO_DEV_ASPEED_ACRY
+	bool "Enable Aspeed ACRY RSA Engine"
+	depends on CRYPTO_DEV_ASPEED
+	select CRYPTO_ENGINE
+	select CRYPTO_RSA
+	help
+	  Select here to enable Aspeed ECC/RSA Engine (ACRY)
+	  RSA driver.
+	  Supports 256 bits to 4096 bits RSA encryption/decryption
+	  and signature/verification.