https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/log/?h=linker/orphans/warn/v5 v5: - rebase from -rc2 to -rc7 to avoid build failures on Clang vs binutils - include Arvind's GOT fix-up series[3], since it touches many similar areas - add PGO/AutoFDO section patch[4] - split up x86 and arm changes into more digestable steps - move several sections out of DISCARD and into zero-size asserts - introduce COMMON_DISCARDS to improve ARM's linker scripts v4: https://lore.kernel.org/lkml/20200629061840.4065483-1-keescook@xxxxxxxxxxxx/ v3: https://lore.kernel.org/lkml/20200624014940.1204448-1-keescook@xxxxxxxxxxxx/ v2: https://lore.kernel.org/lkml/20200622205815.2988115-1-keescook@xxxxxxxxxxxx/ v1: https://lore.kernel.org/lkml/20200228002244.15240-1-keescook@xxxxxxxxxxxx/ A recent bug[1] was solved for builds linked with ld.lld, and tracking it down took way longer than it needed to (a year). Ultimately, it boiled down to differences between ld.bfd and ld.lld's handling of orphan sections. Similar situation have continued to recur, and it's clear the kernel build needs to be much more explicit about linker sections. Similarly, the recent FGKASLR series brought up orphan section handling too[2]. In all cases, it would have been nice if the linker was running with --orphan-handling=warn so that surprise sections wouldn't silently get mapped into the kernel image at locations up to the whim of the linker's orphan handling logic. Instead, all desired sections should be explicitly identified in the linker script (to be either kept, discarded, or verified to be zero-sized) with any orphans throwing a warning. The powerpc architecture has actually been doing this for some time, so this series just extends that coverage to x86, arm, and arm64. This has gotten sucecssful build testing under the following matrix: compiler/linker: gcc+ld.bfd, clang+ld.lld targets: defconfig, allmodconfig architectures: x86, i386, arm64, arm versions: v5.8-rc7, next-20200731 (with various build fixes[7][8]) Two known-failure exceptions (unchanged by this series) being: - clang+arm/arm64 needs CONFIG_CPU_BIG_ENDIAN=n to pass allmodconfig[5] - clang+i386 only builds in -next, which was recently fixed[6] All three architectures depend on the first several commits to vmlinux.lds.h. x86 depends on Arvind's GOT series[3], so I collected it into this version of my series, as it hadn't been taken into -tip yet. arm64 depends on the efi/libstub patch. As such, I'd like to land this series as a whole. Given that two thirds of it is in the arm universe, perhaps this can land via the arm64 tree? If x86 -tip is preferred, that works too. If I don't hear otherwise, I will just carry this myself in -next. In all cases, I would really appreciate reviews/acks/etc. :) Thanks! -Kees [1] https://github.com/ClangBuiltLinux/linux/issues/282 [2] https://lore.kernel.org/lkml/202002242122.AA4D1B8@keescook/ [3] https://lore.kernel.org/lkml/20200715004133.1430068-1-nivedita@xxxxxxxxxxxx/ [4] https://lore.kernel.org/lkml/20200625184752.73095-1-ndesaulniers@xxxxxxxxxx/ [5] https://github.com/ClangBuiltLinux/linux/issues/1071 [6] https://github.com/ClangBuiltLinux/linux/issues/194 [7] https://lore.kernel.org/lkml/1596166744-2954-2-git-send-email-neal.liu@xxxxxxxxxxxx/ [8] https://lore.kernel.org/lkml/82f750c4-d423-1ed8-a158-e75153745e07@xxxxxxxxxx/ Ard Biesheuvel (3): x86/boot/compressed: Move .got.plt entries out of the .got section x86/boot/compressed: Force hidden visibility for all symbol references x86/boot/compressed: Get rid of GOT fixup code Arvind Sankar (4): x86/boot: Add .text.* to setup.ld x86/boot: Remove run-time relocations from .head.text code x86/boot: Remove run-time relocations from head_{32,64}.S x86/boot: Check that there are no run-time relocations Kees Cook (28): vmlinux.lds.h: Create COMMON_DISCARDS vmlinux.lds.h: Add .gnu.version* to COMMON_DISCARDS vmlinux.lds.h: Avoid KASAN and KCSAN's unwanted sections vmlinux.lds.h: Split ELF_DETAILS from STABS_DEBUG vmlinux.lds.h: Add .symtab, .strtab, and .shstrtab to ELF_DETAILS efi/libstub: Disable -mbranch-protection arm64/mm: Remove needless section quotes arm64/kernel: Remove needless Call Frame Information annotations arm64/build: Remove .eh_frame* sections due to unwind tables arm64/build: Use common DISCARDS in linker script arm64/build: Add missing DWARF sections arm64/build: Assert for unwanted sections arm64/build: Warn on orphan section placement arm/build: Refactor linker script headers arm/build: Explicitly keep .ARM.attributes sections arm/build: Add missing sections arm/build: Warn on orphan section placement arm/boot: Handle all sections explicitly arm/boot: Warn on orphan section placement x86/asm: Avoid generating unused kprobe sections x86/build: Enforce an empty .got.plt section x86/build: Assert for unwanted sections x86/build: Warn on orphan section placement x86/boot/compressed: Reorganize zero-size section asserts x86/boot/compressed: Remove, discard, or assert for unwanted sections x86/boot/compressed: Add missing debugging sections to output x86/boot/compressed: Warn on orphan section placement arm/build: Assert for unwanted sections Nick Desaulniers (1): vmlinux.lds.h: add PGO and AutoFDO input sections arch/alpha/kernel/vmlinux.lds.S | 1 + arch/arc/kernel/vmlinux.lds.S | 1 + arch/arm/Makefile | 4 + arch/arm/boot/compressed/Makefile | 2 + arch/arm/boot/compressed/vmlinux.lds.S | 20 +-- .../arm/{kernel => include/asm}/vmlinux.lds.h | 29 ++- arch/arm/kernel/vmlinux-xip.lds.S | 8 +- arch/arm/kernel/vmlinux.lds.S | 8 +- arch/arm64/Makefile | 9 +- arch/arm64/kernel/smccc-call.S | 2 - arch/arm64/kernel/vmlinux.lds.S | 28 ++- arch/arm64/mm/mmu.c | 2 +- arch/csky/kernel/vmlinux.lds.S | 1 + arch/hexagon/kernel/vmlinux.lds.S | 1 + arch/ia64/kernel/vmlinux.lds.S | 1 + arch/mips/kernel/vmlinux.lds.S | 1 + arch/nds32/kernel/vmlinux.lds.S | 1 + arch/nios2/kernel/vmlinux.lds.S | 1 + arch/openrisc/kernel/vmlinux.lds.S | 1 + arch/parisc/boot/compressed/vmlinux.lds.S | 1 + arch/parisc/kernel/vmlinux.lds.S | 1 + arch/powerpc/kernel/vmlinux.lds.S | 2 +- arch/riscv/kernel/vmlinux.lds.S | 1 + arch/s390/kernel/vmlinux.lds.S | 1 + arch/sh/kernel/vmlinux.lds.S | 1 + arch/sparc/kernel/vmlinux.lds.S | 1 + arch/um/kernel/dyn.lds.S | 2 +- arch/um/kernel/uml.lds.S | 2 +- arch/unicore32/kernel/vmlinux.lds.S | 1 + arch/x86/Makefile | 4 + arch/x86/boot/compressed/Makefile | 41 +---- arch/x86/boot/compressed/head_32.S | 99 ++++------- arch/x86/boot/compressed/head_64.S | 165 +++++++----------- arch/x86/boot/compressed/mkpiggy.c | 6 + arch/x86/boot/compressed/vmlinux.lds.S | 48 ++++- arch/x86/boot/setup.ld | 2 +- arch/x86/include/asm/asm.h | 6 +- arch/x86/kernel/vmlinux.lds.S | 39 ++++- drivers/firmware/efi/libstub/Makefile | 11 +- drivers/firmware/efi/libstub/hidden.h | 6 - include/asm-generic/vmlinux.lds.h | 49 +++++- include/linux/hidden.h | 19 ++ 42 files changed, 377 insertions(+), 252 deletions(-) rename arch/arm/{kernel => include/asm}/vmlinux.lds.h (84%) delete mode 100644 drivers/firmware/efi/libstub/hidden.h create mode 100644 include/linux/hidden.h -- 2.25.1
