Hi Ingo, Based on my testing, this is ready to go. I've reviewed the feedback on v5 and made a few small changes, noted below. https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/log/?h=linker/orphans/warn/v6 v6: - rebase to -tip x86/boot - remove 0-sized NOLOAD - move .got.plt to end with INFO (NOLOAD warns) - add Reviewed-bys v5: https://lore.kernel.org/lkml/20200731230820.1742553-1-keescook@xxxxxxxxxxxx/ 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: -tip x86/boot All three architectures depend on the first several commits to vmlinux.lds.h. x86 depends on Arvind's GOT series (in -tip x86/boot now). arm64 depends on the efi/libstub patch. As such, I'd like to land this series as a whole. Ingo has suggested he'd take it into -tip. Thanks! -Kees [1] https://github.com/ClangBuiltLinux/linux/issues/282 [2] https://lore.kernel.org/lkml/202002242122.AA4D1B8@keescook/ 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: Assert for unwanted 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 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 | 30 ++++++++-- 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/x86/Makefile | 4 ++ arch/x86/boot/compressed/Makefile | 2 + arch/x86/boot/compressed/vmlinux.lds.S | 58 +++++++++++++------ arch/x86/include/asm/asm.h | 6 +- arch/x86/kernel/vmlinux.lds.S | 39 ++++++++++++- drivers/firmware/efi/libstub/Makefile | 9 ++- include/asm-generic/vmlinux.lds.h | 49 +++++++++++++--- 35 files changed, 241 insertions(+), 60 deletions(-) rename arch/arm/{kernel => include/asm}/vmlinux.lds.h (84%) -- 2.25.1
