Bruce Ashfield
9e2276fa6e
It was observed that the kernel embeds the absolute build path in the x86 boot image when the __FILE__ macro is expanded. > From https://bugzilla.yoctoproject.org/show_bug.cgi?id=13458: If you turn on the buildpaths QA test, or try a reproducible build, you discover that the kernel image contains build paths. $ strings bzImage-5.0.19-yocto-standard |grep tmp/ out of pgt_buf in /data/poky-tmp/reproducible/tmp/work-shared/qemux86-64/kernel-source/arch/x86/boot/compressed/kaslr_64.c!? But what's this in the top-level Makefile: $ git grep prefix-map Makefile:KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=) So the __FILE__ shouldn't be using the full path. However arch/x86/boot/compressed/Makefile has this: KBUILD_CFLAGS := -m$(BITS) -O2 So that clears KBUILD_FLAGS, removing the -fmacro-prefix-map option. Use -fmacro-prefix-map to have relative paths in the boot image too. [ bp: Massage commit message and put the KBUILD_CFLAGS addition in ..boot/Makefile after the KBUILD_AFLAGS assignment because gas doesn't support -fmacro-prefix-map. ] Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com> Signed-off-by: Ross Burton <ross.burton@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: George Rimar <grimar@accesssoftek.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Nathan Chancellor <natechancellor@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190926093226.8568-1-ross.burton@intel.com Link: https://bugzilla.kernel.org/show_bug.cgi?id=204333
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.