From: Thomas Weißschuh Date: Sun, 11 May 2025 06:02:27 +0000 (+0200) Subject: Revert "kbuild: make all file references relative to source root" X-Git-Tag: v6.15-rc7~27^2~2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=020d7f14489b8bc38c6bd4c5b3c25262e8b6de63;p=thirdparty%2Fkernel%2Flinux.git Revert "kbuild: make all file references relative to source root" This reverts commit cacd22ce69585a91c386243cd662ada962431e63. -ffile-prefix-map breaks the ability of debuggers to find the source file corresponding to object files. As there is no simple or uniform way to specify the source directory explicitly, this breaks developers workflows. Revert the unconditional usage of -ffile-prefix-map. Reported-by: Matthieu Baerts Closes: https://lore.kernel.org/lkml/edc50aa7-0740-4942-8c15-96f12f2acc7e@kernel.org/ Reported-by: Ville Syrjälä Closes: https://lore.kernel.org/lkml/aBEttQH4kimHFScx@intel.com/ Fixes: cacd22ce6958 ("kbuild: make all file references relative to source root") Signed-off-by: Thomas Weißschuh Signed-off-by: Masahiro Yamada --- diff --git a/Documentation/kbuild/reproducible-builds.rst b/Documentation/kbuild/reproducible-builds.rst index a7762486c93fc..f2dcc39044e66 100644 --- a/Documentation/kbuild/reproducible-builds.rst +++ b/Documentation/kbuild/reproducible-builds.rst @@ -46,6 +46,21 @@ The kernel embeds the building user and host names in `KBUILD_BUILD_USER and KBUILD_BUILD_HOST`_ variables. If you are building from a git commit, you could use its committer address. +Absolute filenames +------------------ + +When the kernel is built out-of-tree, debug information may include +absolute filenames for the source files. This must be overridden by +including the ``-fdebug-prefix-map`` option in the `KCFLAGS`_ variable. + +Depending on the compiler used, the ``__FILE__`` macro may also expand +to an absolute filename in an out-of-tree build. Kbuild automatically +uses the ``-fmacro-prefix-map`` option to prevent this, if it is +supported. + +The Reproducible Builds web site has more information about these +`prefix-map options`_. + Generated files in source packages ---------------------------------- @@ -116,5 +131,7 @@ See ``scripts/setlocalversion`` for details. .. _KBUILD_BUILD_TIMESTAMP: kbuild.html#kbuild-build-timestamp .. _KBUILD_BUILD_USER and KBUILD_BUILD_HOST: kbuild.html#kbuild-build-user-kbuild-build-host +.. _KCFLAGS: kbuild.html#kcflags +.. _prefix-map options: https://reproducible-builds.org/docs/build-path/ .. _Reproducible Builds project: https://reproducible-builds.org/ .. _SOURCE_DATE_EPOCH: https://reproducible-builds.org/docs/source-date-epoch/ diff --git a/Makefile b/Makefile index 64c514f4bc193..52f84aaf10252 100644 --- a/Makefile +++ b/Makefile @@ -1068,7 +1068,7 @@ KBUILD_CFLAGS += -fno-builtin-wcslen # change __FILE__ to the relative path to the source directory ifdef building_out_of_srctree -KBUILD_CPPFLAGS += $(call cc-option,-ffile-prefix-map=$(srcroot)/=) +KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srcroot)/=) KBUILD_RUSTFLAGS += --remap-path-prefix=$(srcroot)/= endif