diff --git a/debian/changelog b/debian/changelog index 78e5e3b43..9f34a3a80 100644 --- a/debian/changelog +++ b/debian/changelog @@ -3,6 +3,9 @@ linux (4.16.5-2) UNRELEASED; urgency=medium [ Romain Perier ] * [armhf] DRM: Enable DW_HDMI_AHB_AUDIO and DW_HDMI_CEC (Closes: #897204) + [ Ben Hutchings ] + * kbuild: use -fmacro-prefix-map to make __FILE__ a relative path + -- Vagrant Cascadian Mon, 30 Apr 2018 11:23:15 -0700 linux (4.16.5-1) unstable; urgency=medium diff --git a/debian/patches/features/all/kbuild-use-fmacro-prefix-map-to-make-__file__-a-rela.patch b/debian/patches/features/all/kbuild-use-fmacro-prefix-map-to-make-__file__-a-rela.patch new file mode 100644 index 000000000..6f5bc699d --- /dev/null +++ b/debian/patches/features/all/kbuild-use-fmacro-prefix-map-to-make-__file__-a-rela.patch @@ -0,0 +1,45 @@ +From: Masahiro Yamada +Date: Fri, 30 Mar 2018 13:15:26 +0900 +Subject: kbuild: use -fmacro-prefix-map to make __FILE__ a relative path +Origin: https://git.kernel.org/linus/a73619a845d5625079cc1b3b820f44c899618388 + +The __FILE__ macro is used everywhere in the kernel to locate the file +printing the log message, such as WARN_ON(), etc. If the kernel is +built out of tree, this can be a long absolute path, like this: + + WARNING: CPU: 1 PID: 1 at /path/to/build/directory/arch/arm64/kernel/foo.c:... + +This is because Kbuild runs in the objtree instead of the srctree, +then __FILE__ is expanded to a file path prefixed with $(srctree)/. + +Commit 9da0763bdd82 ("kbuild: Use relative path when building in a +subdir of the source tree") improved this to some extent; $(srctree) +becomes ".." if the objtree is a child of the srctree. + +For other cases of out-of-tree build, __FILE__ is still the absolute +path. It also means the kernel image depends on where it was built. + +A brand-new option from GCC, -fmacro-prefix-map, solves this problem. +If your compiler supports it, __FILE__ is the relative path from the +srctree regardless of O= option. This provides more readable log and +more reproducible builds. + +Please note __FILE__ is always an absolute path for external modules. + +Signed-off-by: Masahiro Yamada +--- + Makefile | 3 +++ + 1 file changed, 3 insertions(+) + +--- a/Makefile ++++ b/Makefile +@@ -857,6 +857,9 @@ KBUILD_CFLAGS += $(call cc-option,-Wer + # Require designated initializers for all marked structures + KBUILD_CFLAGS += $(call cc-option,-Werror=designated-init) + ++# change __FILE__ to the relative path from the srctree ++KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=) ++ + # use the deterministic mode of AR if available + KBUILD_ARFLAGS := $(call ar-option,D) + diff --git a/debian/patches/series b/debian/patches/series index 5b097a58c..e6e8a3398 100644 --- a/debian/patches/series +++ b/debian/patches/series @@ -101,6 +101,7 @@ debian/revert-objtool-fix-config_stack_validation-y-warning.patch bugfix/all/i40e-build-for-64-bit-targets-only.patch # Miscellaneous features +features/all/kbuild-use-fmacro-prefix-map-to-make-__file__-a-rela.patch # Lockdown (formerly 'securelevel') patchset features/all/lockdown/0001-Add-the-ability-to-lock-down-access-to-the-running-k.patch