From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers 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 Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- scripts/kconfig/tests/transitional/Kconfig | 132 +++++++++++++++++++++ scripts/kconfig/tests/transitional/__init__.py | 25 ++++ scripts/kconfig/tests/transitional/expected_config | 15 +++ scripts/kconfig/tests/transitional/expected_stdout | 1 + scripts/kconfig/tests/transitional/initial_config | 20 ++++ 5 files changed, 193 insertions(+) create mode 100644 scripts/kconfig/tests/transitional/Kconfig create mode 100644 scripts/kconfig/tests/transitional/__init__.py create mode 100644 scripts/kconfig/tests/transitional/expected_config create mode 100644 scripts/kconfig/tests/transitional/expected_stdout create mode 100644 scripts/kconfig/tests/transitional/initial_config (limited to 'scripts/kconfig/tests/transitional') diff --git a/scripts/kconfig/tests/transitional/Kconfig b/scripts/kconfig/tests/transitional/Kconfig new file mode 100644 index 000000000..faa4d396f --- /dev/null +++ b/scripts/kconfig/tests/transitional/Kconfig @@ -0,0 +1,132 @@ +# SPDX-License-Identifier: GPL-2.0 +# Test transitional symbols for config migration with all Kconfig types + +# Enable module support for tristate testing +config MODULES + bool "Enable loadable module support" + modules + default y + +# Basic migration tests for all types +config NEW_BOOL + bool "New bool option" + default OLD_BOOL + +config OLD_BOOL + bool + transitional + +config NEW_TRISTATE + tristate "New tristate option" + default OLD_TRISTATE + +config OLD_TRISTATE + tristate + transitional + +config NEW_STRING + string "New string option" + default OLD_STRING + +config OLD_STRING + string + transitional + +config NEW_HEX + hex "New hex option" + default OLD_HEX + +config OLD_HEX + hex + transitional + +config NEW_INT + int "New int option" + default OLD_INT + +config OLD_INT + int + transitional + +# Precedence tests for all types +config NEW_BOOL_PRECEDENCE + bool "New bool option with precedence" + default OLD_BOOL_PRECEDENCE + +config OLD_BOOL_PRECEDENCE + bool + transitional + +config NEW_STRING_PRECEDENCE + string "New string option with precedence" + default OLD_STRING_PRECEDENCE + +config OLD_STRING_PRECEDENCE + string + transitional + +config NEW_TRISTATE_PRECEDENCE + tristate "New tristate option with precedence" + default OLD_TRISTATE_PRECEDENCE + +config OLD_TRISTATE_PRECEDENCE + tristate + transitional + +config NEW_HEX_PRECEDENCE + hex "New hex option with precedence" + default OLD_HEX_PRECEDENCE + +config OLD_HEX_PRECEDENCE + hex + transitional + +config NEW_INT_PRECEDENCE + int "New int option with precedence" + default OLD_INT_PRECEDENCE + +config OLD_INT_PRECEDENCE + int + transitional + +# Test that help sections are allowed for transitional symbols +config OLD_WITH_HELP + bool + transitional + help + This transitional symbol has a help section to validate that help is allowed. + +# Test that we can set something to =n via transitional symbol +config NEW_DISABLED + tristate "Check for setting to disabled" + default OLD_DISABLED + +config OLD_DISABLED + tristate + transitional + +# Test that a potential new value disappears if it lacks a prompt +config NEW_DISABLED_UNSAVED + tristate + default OLD_DISABLED + +config OLD_DISABLED_UNSAVED + tristate + transitional + +# Test conditional default: transitional value should not prevent prompting +# when default visibility makes the expression evaluate to 'no' +config DEPENDENCY_TEST + bool "Dependency for testing" + default n + +config NEW_CONDITIONAL_DEFAULT + bool "New option with conditional default" + default OLD_CONDITIONAL_DEFAULT if DEPENDENCY_TEST + +config OLD_CONDITIONAL_DEFAULT + bool + transitional + +config REGULAR_OPTION + bool "Regular option" diff --git a/scripts/kconfig/tests/transitional/__init__.py b/scripts/kconfig/tests/transitional/__init__.py new file mode 100644 index 000000000..b50ba2397 --- /dev/null +++ b/scripts/kconfig/tests/transitional/__init__.py @@ -0,0 +1,25 @@ +# SPDX-License-Identifier: GPL-2.0 +""" +Test transitional symbol migration functionality for all Kconfig types. + +This tests that: +- OLD_* options in existing .config cause NEW_* options to be set +- OLD_* options are not written to the new .config file +- NEW_* options appear in the new .config file with correct values +- NEW_* options with defaults from transitional symbols are not prompted +- All Kconfig types work correctly: bool, tristate, string, hex, int +- User-set NEW values take precedence over conflicting OLD transitional values +""" + +def test(conf): + # Run olddefconfig to process the migration with the initial config + assert conf.olddefconfig(dot_config='initial_config') == 0 + + # Check that the configuration matches expected output + assert conf.config_contains('expected_config') + + # Test oldconfig to ensure symbols with transitional defaults are not prompted + assert conf.oldconfig(dot_config='initial_config', in_keys='n\n') == 0 + + # Except for when conditional default evaluates to 'no' + assert conf.stdout_contains('expected_stdout') diff --git a/scripts/kconfig/tests/transitional/expected_config b/scripts/kconfig/tests/transitional/expected_config new file mode 100644 index 000000000..e01f5f070 --- /dev/null +++ b/scripts/kconfig/tests/transitional/expected_config @@ -0,0 +1,15 @@ +CONFIG_MODULES=y +CONFIG_NEW_BOOL=y +CONFIG_NEW_TRISTATE=m +CONFIG_NEW_STRING="test string" +CONFIG_NEW_HEX=0x1234 +CONFIG_NEW_INT=42 +# CONFIG_NEW_BOOL_PRECEDENCE is not set +CONFIG_NEW_STRING_PRECEDENCE="user value" +CONFIG_NEW_TRISTATE_PRECEDENCE=y +CONFIG_NEW_HEX_PRECEDENCE=0xABCD +CONFIG_NEW_INT_PRECEDENCE=100 +# CONFIG_NEW_DISABLED is not set +# CONFIG_DEPENDENCY_TEST is not set +# CONFIG_NEW_CONDITIONAL_DEFAULT is not set +# CONFIG_REGULAR_OPTION is not set diff --git a/scripts/kconfig/tests/transitional/expected_stdout b/scripts/kconfig/tests/transitional/expected_stdout new file mode 100644 index 000000000..6f0b285d6 --- /dev/null +++ b/scripts/kconfig/tests/transitional/expected_stdout @@ -0,0 +1 @@ +New option with conditional default (NEW_CONDITIONAL_DEFAULT) [N/y/?] (NEW) n diff --git a/scripts/kconfig/tests/transitional/initial_config b/scripts/kconfig/tests/transitional/initial_config new file mode 100644 index 000000000..68b7da672 --- /dev/null +++ b/scripts/kconfig/tests/transitional/initial_config @@ -0,0 +1,20 @@ +CONFIG_MODULES=y +CONFIG_OLD_BOOL=y +CONFIG_OLD_TRISTATE=m +CONFIG_OLD_STRING="test string" +CONFIG_OLD_HEX=0x1234 +CONFIG_OLD_INT=42 +# CONFIG_NEW_BOOL_PRECEDENCE is not set +CONFIG_OLD_BOOL_PRECEDENCE=y +CONFIG_NEW_STRING_PRECEDENCE="user value" +CONFIG_OLD_STRING_PRECEDENCE="old value" +CONFIG_NEW_TRISTATE_PRECEDENCE=y +CONFIG_OLD_TRISTATE_PRECEDENCE=m +CONFIG_NEW_HEX_PRECEDENCE=0xABCD +CONFIG_OLD_HEX_PRECEDENCE=0x5678 +CONFIG_NEW_INT_PRECEDENCE=100 +CONFIG_OLD_INT_PRECEDENCE=200 +# CONFIG_OLD_DISABLED is not set +# CONFIG_OLD_DISABLED_UNSAVED is not set +# CONFIG_DEPENDENCY_TEST is not set +CONFIG_OLD_CONDITIONAL_DEFAULT=y -- cgit v1.3.1