kernel/linux.git/tools/objtool/arch/x86, branch v6.18.21

objtool: Handle Clang RSP musical chairs

2026-04-02T11:23:01+00:00

[ Upstream commit 7fdaa640c810cb42090a182c33f905bcc47a616a ] For no apparent reason (possibly related to CONFIG_KMSAN), Clang can randomly pass the value of RSP to other registers and then back again to RSP. Handle that accordingly. Fixes the following warnings: drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: undefined stack state drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: unknown CFA base reg -1 Reported-by: Arnd Bergmann Closes: https://lore.kernel.org/90956545-2066-46e3-b547-10c884582eb0@app.fastmail.com Link: https://patch.msgid.link/240e6a172cc73292499334a3724d02ccb3247fc7.1772818491.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf Signed-off-by: Sasha Levin

objtool: Add action to check for absence of absolute relocations

2025-09-03T15:59:51+00:00

The x86 startup code must not use absolute references to code or data, as it executes before the kernel virtual mapping is up. Add an action to objtool to check all allocatable sections (with the exception of __patchable_function_entries, which uses absolute references for nebulous reasons) and raise an error if any absolute references are found. Note that debug sections typically contain lots of absolute references too, but those are not allocatable so they will be ignored. Signed-off-by: Ard Biesheuvel Signed-off-by: Borislav Petkov (AMD) Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/20250828102202.1849035-39-ardb+git@google.com

Merge commit 'its-for-linus-20250509-merge' into x86/core, to resolve conflicts

2025-05-13T08:47:10+00:00

Conflicts: Documentation/admin-guide/hw-vuln/index.rst arch/x86/include/asm/cpufeatures.h arch/x86/kernel/alternative.c arch/x86/kernel/cpu/bugs.c arch/x86/kernel/cpu/common.c drivers/base/cpu.c include/linux/cpu.h Signed-off-by: Ingo Molnar

x86/its: FineIBT-paranoid vs ITS

2025-05-09T20:39:36+00:00

FineIBT-paranoid was using the retpoline bytes for the paranoid check, disabling retpolines, because all parts that have IBT also have eIBRS and thus don't need no stinking retpolines. Except... ITS needs the retpolines for indirect calls must not be in the first half of a cacheline :-/ So what was the paranoid call sequence: : 0: 41 ba 78 56 34 12 mov $0x12345678, %r10d 6: 45 3b 53 f7 cmp -0x9(%r11), %r10d a: 4d 8d 5b lea -0x10(%r11), %r11 e: 75 fd jne d 10: 41 ff d3 call *%r11 13: 90 nop Now becomes: : 0: 41 ba 78 56 34 12 mov $0x12345678, %r10d 6: 45 3b 53 f7 cmp -0x9(%r11), %r10d a: 4d 8d 5b f0 lea -0x10(%r11), %r11 e: 2e e8 XX XX XX XX cs call __x86_indirect_paranoid_thunk_r11 Where the paranoid_thunk looks like: 1d: (bad) __x86_indirect_paranoid_thunk_r11: 1e: 75 fd jne 1d __x86_indirect_its_thunk_r11: 20: 41 ff eb jmp *%r11 23: cc int3 [ dhansen: remove initialization to false ] Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Pawan Gupta Signed-off-by: Dave Hansen Reviewed-by: Alexandre Chartre

x86/boot: Add a bunch of PIC aliases

2025-05-04T13:59:43+00:00

Add aliases for all the data objects that the startup code references - this is needed so that this code can be moved into its own confined area where it can only access symbols that have a __pi_ prefix. Signed-off-by: Ard Biesheuvel Signed-off-by: Ingo Molnar Cc: Arnd Bergmann Cc: David Woodhouse Cc: Dionna Amalie Glaze Cc: H. Peter Anvin Cc: Kees Cook Cc: Kevin Loughlin Cc: Len Brown Cc: Linus Torvalds Cc: Rafael J. Wysocki Cc: Tom Lendacky Cc: linux-efi@vger.kernel.org Link: https://lore.kernel.org/r/20250504095230.2932860-39-ardb+git@google.com

objtool: Fix false-positive "ignoring unreachables" warning

2025-04-10T20:55:00+00:00

There's no need to try to automatically disable unreachable warnings if they've already been manually disabled due to CONFIG_KCOV quirks. This avoids a spurious warning with a KCOV kernel: fs/smb/client/cifs_unicode.o: warning: objtool: cifsConvertToUTF16.part.0+0xce5: ignoring unreachables due to jump table quirk Fixes: eeff7ac61526 ("objtool: Warn when disabling unreachable warnings") Reported-by: kernel test robot Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/5eb28eeb6a724b7d945a961cfdcf8d41e6edf3dc.1744238814.git.jpoimboe@kernel.org Closes: https://lore.kernel.org/r/202504090910.QkvTAR36-lkp@intel.com/

objtool: Split INSN_CONTEXT_SWITCH into INSN_SYSCALL and INSN_SYSRET

2025-04-08T07:14:11+00:00

INSN_CONTEXT_SWITCH is ambiguous. It can represent both call semantics (SYSCALL, SYSENTER) and return semantics (SYSRET, IRET, RETS, RETU). Those differ significantly: calls preserve control flow whereas returns terminate it. Objtool uses an arbitrary rule for INSN_CONTEXT_SWITCH that almost works by accident: if in a function, keep going; otherwise stop. It should instead be based on the semantics of the underlying instruction. In preparation for improving that, split INSN_CONTEXT_SWITCH into INSN_SYCALL and INSN_SYSRET. No functional change. Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://lore.kernel.org/r/19a76c74d2c051d3bc9a775823cafc65ad267a7a.1744095216.git.jpoimboe@kernel.org

objtool: Change "warning:" to "error: " for fatal errors

2025-04-01T07:07:13+00:00

This is similar to GCC's behavior and makes it more obvious why the build failed. Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://lore.kernel.org/r/0ea76f4b0e7a370711ed9f75fd0792bb5979c2bf.1743481539.git.jpoimboe@kernel.org

objtool: Fix X86_FEATURE_SMAP alternative handling

2025-03-25T08:20:26+00:00

For X86_FEATURE_SMAP alternatives which replace NOP with STAC or CLAC, uaccess validation skips the NOP branch to avoid following impossible code paths, e.g. where a STAC would be patched but a CLAC wouldn't. However, it's not safe to assume an X86_FEATURE_SMAP alternative is patching STAC/CLAC. There can be other alternatives, like static_cpu_has(), where both branches need to be validated. Fix that by repurposing ANNOTATE_IGNORE_ALTERNATIVE for skipping either original instructions or new ones. This is a more generic approach which enables the removal of the feature checking hacks and the insn->ignore bit. Fixes the following warnings: arch/x86/mm/fault.o: warning: objtool: do_user_addr_fault+0x8ec: __stack_chk_fail() missing __noreturn in .c/.h or NORETURN() in noreturns.h arch/x86/mm/fault.o: warning: objtool: do_user_addr_fault+0x8f1: unreachable instruction [ mingo: Fix up conflicts with recent x86 changes. ] Fixes: ea24213d8088 ("objtool: Add UACCESS validation") Reported-by: kernel test robot Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://lore.kernel.org/r/de0621ca242130156a55d5d74fed86994dfa4c9c.1742852846.git.jpoimboe@kernel.org Closes: https://lore.kernel.org/oe-kbuild-all/202503181736.zkZUBv4N-lkp@intel.com/

objtool: Warn when disabling unreachable warnings

2025-03-25T08:20:25+00:00

Print a warning when disabling the unreachable warnings (due to a GCC bug). This will help determine if recent GCCs still have the issue and alert us if any other issues might be silently lurking behind the unreachable disablement. Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://lore.kernel.org/r/df243063787596e6031367e6659e7e43409d6c6d.1742852846.git.jpoimboe@kernel.org