Messages in this thread | | | From | Josh Poimboeuf <> | Subject | [PATCH v2 00/22] x86, objtool: several fixes/improvements | Date | Wed, 17 Jul 2019 20:36:35 -0500 |
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v2: - Use ud2 instead of calling kvm_spurious_fault() in vmx_vmenter() [Paolo] - Fix ____kvm_handle_fault_on_reboot() comment [Paolo] - Tweak "switch jump table" comment [Peter] - Add review tags
Patches also available at: git://git.kernel.org/pub/scm/linux/kernel/git/jpoimboe/linux.git objtool-many-fixes-v2
v1 was posted here: https://lkml.kernel.org/r/cover.1563150885.git.jpoimboe@redhat.com
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There have been a lot of objtool bug reports lately, mainly related to Clang and BPF. As part of fixing those bugs, I added some improvements to objtool which uncovered yet more bugs (some kernel, some objtool).
I've given these patches a lot of testing with both GCC and Clang. More compile testing of objtool would be appreciated, as the kbuild test robot doesn't seem to be paying much attention to my branches lately.
There are still at least three outstanding issues:
1) With clang I see:
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: .altinstr_replacement+0x88: redundant UACCESS disable
I haven't dug into it yet.
2) There's also an issue in clang where a large switch table had a bunch of unused (bad) entries. It's not a code correctness issue, but hopefully it can get fixed in clang anyway. See patch 20/22 for more details.
3) CONFIG_LIVEPATCH is causing some objtool "unreachable instruction" warnings due to the new -flive-patching flag. I have some fixes pending, but this patch set is already long enough.
Jann Horn (1): objtool: Support repeated uses of the same C jump table
Josh Poimboeuf (21): x86/paravirt: Fix callee-saved function ELF sizes x86/kvm: Fix fastop function ELF metadata x86/kvm: Replace vmx_vmenter()'s call to kvm_spurious_fault() with UD2 x86/kvm: Don't call kvm_spurious_fault() from .fixup x86/entry: Fix thunk function ELF sizes x86/head/64: Annotate start_cpu0() as non-callable x86/uaccess: Remove ELF function annotation from copy_user_handle_tail() x86/uaccess: Don't leak AC flag into fentry from mcsafe_handle_tail() x86/uaccess: Remove redundant CLACs in getuser/putuser error paths bpf: Disable GCC -fgcse optimization for ___bpf_prog_run() objtool: Add mcsafe_handle_tail() to the uaccess safe list objtool: Track original function across branches objtool: Refactor function alias logic objtool: Warn on zero-length functions objtool: Change dead_end_function() to return boolean objtool: Do frame pointer check before dead end check objtool: Refactor sibling call detection logic objtool: Refactor jump table code objtool: Fix seg fault on bad switch table entry objtool: convert insn type to enum objtool: Support conditional retpolines
arch/x86/entry/thunk_64.S | 5 +- arch/x86/include/asm/kvm_host.h | 34 ++-- arch/x86/include/asm/paravirt.h | 1 + arch/x86/kernel/head_64.S | 4 +- arch/x86/kernel/kvm.c | 1 + arch/x86/kvm/emulate.c | 44 +++-- arch/x86/kvm/vmx/vmenter.S | 6 +- arch/x86/lib/copy_user_64.S | 2 +- arch/x86/lib/getuser.S | 20 +-- arch/x86/lib/putuser.S | 29 +-- arch/x86/lib/usercopy_64.c | 2 +- include/linux/compiler-gcc.h | 2 + include/linux/compiler_types.h | 4 + kernel/bpf/core.c | 2 +- tools/objtool/arch.h | 36 ++-- tools/objtool/arch/x86/decode.c | 2 +- tools/objtool/check.c | 308 ++++++++++++++++---------------- tools/objtool/check.h | 3 +- tools/objtool/elf.c | 4 +- tools/objtool/elf.h | 3 +- 20 files changed, 278 insertions(+), 234 deletions(-)
-- 2.20.1
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