Hi, This series enables objtool to start doing stack validation on arm64 kernel builds. It relies on the previous series I sent, refactoring the arm64 decoder [1]. First, the aarch64 instruction decoder needed to be made available to code under tools/. This is done in a similar manner to x86 instruction decoded. One limitation I encountered there is that most of aarch64 instruction decoder is __kprobe annotated. To bypass that it remove the kprobe include and had to add an empty __kprobe definition, but I'd welcome a proper solution to that. Then instruction semantics are progressively added so objtool can track the stack state through the execution flow. There are a few things that needed consideration: - Generation of constants within executable sections, these either caused objtool to fail decoding or to wrongly decode constants as jumps or other instructions affecting execution flow and causing confusion. To solve this, tracking locations referenced by instructions using literals was needed. - Jump tables from switch statements in aarch64 don't have enough information to link branches with the branch instruction leading to them. For this, we use a gcc plugin to add some information to establish those missing links in a format that is already supported by objtool With this, there are still some errors when building with objtool. A number of cleanups/annotations are needed on the arm64, as well as handling SYM_DATA objects in objtool. Those changes can be found on top of this branch here: git clone https://github.com/julien-thierry/linux.git -b objtoolxarm64-latest But it would be nice to have some feedback on this before I start submitting everyting. [1] https://lkml.org/lkml/2021/1/20/791 Thanks, Julien --> Julien Thierry (15): tools: Add some generic functions and headers tools: arm64: Make aarch64 instruction decoder available to tools tools: bug: Remove duplicate definition objtool: arm64: Add base definition for arm64 backend objtool: arm64: Decode add/sub instructions objtool: arm64: Decode jump and call related instructions objtool: arm64: Decode other system instructions objtool: arm64: Decode load/store instructions objtool: arm64: Decode LDR instructions objtool: arm64: Accept padding in code sections efi: libstub: Ignore relocations for .discard sections objtool: arm64: Implement functions to add switch tables alternatives objtool: arm64: Cache section with switch table information objtool: arm64: Handle supported relocations in alternatives objtool: arm64: Ignore replacement section for alternative callback Raphael Gault (2): gcc-plugins: objtool: Add plugin to detect switch table on arm64 objtool: arm64: Enable stack validation for arm64 arch/arm64/Kconfig | 2 + drivers/firmware/efi/libstub/Makefile | 2 +- scripts/Makefile.gcc-plugins | 2 + scripts/gcc-plugins/Kconfig | 4 + .../arm64_switch_table_detection_plugin.c | 85 + tools/arch/arm64/include/asm/aarch64-insn.h | 551 +++++++ tools/arch/arm64/lib/aarch64-insn.c | 1425 +++++++++++++++++ tools/include/asm-generic/bitops/__ffs.h | 11 + tools/include/linux/bug.h | 6 +- tools/include/linux/kernel.h | 21 + tools/include/linux/printk.h | 40 + tools/objtool/Makefile | 5 + tools/objtool/arch/arm64/Build | 8 + tools/objtool/arch/arm64/decode.c | 471 ++++++ .../arch/arm64/include/arch/cfi_regs.h | 14 + tools/objtool/arch/arm64/include/arch/elf.h | 6 + .../arch/arm64/include/arch/endianness.h | 9 + .../objtool/arch/arm64/include/arch/special.h | 23 + tools/objtool/arch/arm64/special.c | 134 ++ tools/objtool/arch/x86/decode.c | 5 + tools/objtool/check.c | 6 + tools/objtool/include/objtool/arch.h | 3 + tools/objtool/sync-check.sh | 5 + 23 files changed, 2832 insertions(+), 6 deletions(-) create mode 100644 scripts/gcc-plugins/arm64_switch_table_detection_plugin.c create mode 100644 tools/arch/arm64/include/asm/aarch64-insn.h create mode 100644 tools/arch/arm64/lib/aarch64-insn.c create mode 100644 tools/include/linux/printk.h create mode 100644 tools/objtool/arch/arm64/Build create mode 100644 tools/objtool/arch/arm64/decode.c create mode 100644 tools/objtool/arch/arm64/include/arch/cfi_regs.h create mode 100644 tools/objtool/arch/arm64/include/arch/elf.h create mode 100644 tools/objtool/arch/arm64/include/arch/endianness.h create mode 100644 tools/objtool/arch/arm64/include/arch/special.h create mode 100644 tools/objtool/arch/arm64/special.c -- 2.25.4
