linux/tools/objtool/arch, branch v6.15

x86/its: FineIBT-paranoid vs ITS

2025-05-09T20:39:36Z

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

objtool: Fix false-positive "ignoring unreachables" warning

2025-04-10T20:55:00Z

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

2025-04-08T07:14:11Z

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

Merge tag 'objtool-urgent-2025-04-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-04-02T17:30:10Z

Pull objtool fixes from Ingo Molnar: "These are objtool fixes and updates by Josh Poimboeuf, centered around the fallout from the new CONFIG_OBJTOOL_WERROR=y feature, which, despite its default-off nature, increased the profile/impact of objtool warnings: - Improve error handling and the presentation of warnings/errors - Revert the new summary warning line that some test-bot tools interpreted as new regressions - Fix a number of objtool warnings in various drivers, core kernel code and architecture code. About half of them are potential problems related to out-of-bounds accesses or potential undefined behavior, the other half are additional objtool annotations - Update objtool to latest (known) compiler quirks and objtool bugs triggered by compiler code generation - Misc fixes" * tag 'objtool-urgent-2025-04-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits) objtool/loongarch: Add unwind hints in prepare_frametrace() rcu-tasks: Always inline rcu_irq_work_resched() context_tracking: Always inline ct_{nmi,irq}_{enter,exit}() sched/smt: Always inline sched_smt_active() objtool: Fix verbose disassembly if CROSS_COMPILE isn't set objtool: Change "warning:" to "error: " for fatal errors objtool: Always fail on fatal errors Revert "objtool: Increase per-function WARN_FUNC() rate limit" objtool: Append "()" to function name in "unexpected end of section" warning objtool: Ignore end-of-section jumps for KCOV/GCOV objtool: Silence more KCOV warnings, part 2 objtool, drm/vmwgfx: Don't ignore vmw_send_msg() for ORC objtool: Fix STACK_FRAME_NON_STANDARD for cold subfunctions objtool: Fix segfault in ignore_unreachable_insn() objtool: Fix NULL printf() '%s' argument in builtin-check.c:save_argv() objtool, lkdtm: Obfuscate the do_nothing() pointer objtool, regulator: rk808: Remove potential undefined behavior in rk806_set_mode_dcdc() objtool, ASoC: codecs: wcd934x: Remove potential undefined behavior in wcd934x_slim_irq_handler() objtool, Input: cyapa - Remove undefined behavior in cyapa_update_fw_store() objtool, panic: Disable SMAP in __stack_chk_fail() ...

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

2025-04-01T07:07:13Z

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

Merge tag 'powerpc-6.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2025-03-28T02:39:08Z

Pull powerpc updates from Madhavan Srinivasan: - Remove support for IBM Cell Blades - SMP support for microwatt platform - Support for inline static calls on PPC32 - Enable pmu selftests for power11 platform - Enable hardware trace macro (HTM) hcall support - Support for limited address mode capability - Changes to RMA size from 512 MB to 768 MB to handle fadump - Misc fixes and cleanups Thanks to Abhishek Dubey, Amit Machhiwal, Andreas Schwab, Arnd Bergmann, Athira Rajeev, Avnish Chouhan, Christophe Leroy, Disha Goel, Donet Tom, Gaurav Batra, Gautam Menghani, Hari Bathini, Kajol Jain, Kees Cook, Mahesh Salgaonkar, Michael Ellerman, Paul Mackerras, Ritesh Harjani (IBM), Sathvika Vasireddy, Segher Boessenkool, Sourabh Jain, Vaibhav Jain, and Venkat Rao Bagalkote. * tag 'powerpc-6.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (61 commits) powerpc/kexec: fix physical address calculation in clear_utlb_entry() crypto: powerpc: Mark ghashp8-ppc.o as an OBJECT_FILES_NON_STANDARD powerpc: Fix 'intra_function_call not a direct call' warning powerpc/perf: Fix ref-counting on the PMU 'vpa_pmu' KVM: PPC: Enable CAP_SPAPR_TCE_VFIO on pSeries KVM guests powerpc/prom_init: Fixup missing #size-cells on PowerBook6,7 powerpc/microwatt: Add SMP support powerpc: Define config option for processors with broadcast TLBIE powerpc/microwatt: Define an idle power-save function powerpc/microwatt: Device-tree updates powerpc/microwatt: Select COMMON_CLK in order to get the clock framework net: toshiba: Remove reference to PPC_IBM_CELL_BLADE net: spider_net: Remove powerpc Cell driver cpufreq: ppc_cbe: Remove powerpc Cell driver genirq: Remove IRQ_EDGE_EOI_HANDLER docs: Remove reference to removed CBE_CPUFREQ_SPU_GOVERNOR powerpc: Remove UDBG_RTAS_CONSOLE powerpc/io: Use standard barrier macros in io.c powerpc/io: Rename _insw_ns() etc. powerpc/io: Use generic raw accessors ...

objtool: Fix X86_FEATURE_SMAP alternative handling

2025-03-25T08:20:26Z

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

2025-03-25T08:20:25Z

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

Merge tag 'x86-core-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-03-25T05:06:11Z

Pull core x86 updates from Ingo Molnar: "x86 CPU features support: - Generate the header based on build config (H. Peter Anvin, Xin Li) - x86 CPUID parsing updates and fixes (Ahmed S. Darwish) - Introduce the 'setcpuid=' boot parameter (Brendan Jackman) - Enable modifying CPU bug flags with '{clear,set}puid=' (Brendan Jackman) - Utilize CPU-type for CPU matching (Pawan Gupta) - Warn about unmet CPU feature dependencies (Sohil Mehta) - Prepare for new Intel Family numbers (Sohil Mehta) Percpu code: - Standardize & reorganize the x86 percpu layout and related cleanups (Brian Gerst) - Convert the stackprotector canary to a regular percpu variable (Brian Gerst) - Add a percpu subsection for cache hot data (Brian Gerst) - Unify __pcpu_op{1,2}_N() macros to __pcpu_op_N() (Uros Bizjak) - Construct __percpu_seg_override from __percpu_seg (Uros Bizjak) MM: - Add support for broadcast TLB invalidation using AMD's INVLPGB instruction (Rik van Riel) - Rework ROX cache to avoid writable copy (Mike Rapoport) - PAT: restore large ROX pages after fragmentation (Kirill A. Shutemov, Mike Rapoport) - Make memremap(MEMREMAP_WB) map memory as encrypted by default (Kirill A. Shutemov) - Robustify page table initialization (Kirill A. Shutemov) - Fix flush_tlb_range() when used for zapping normal PMDs (Jann Horn) - Clear _PAGE_DIRTY for kernel mappings when we clear _PAGE_RW (Matthew Wilcox) KASLR: - x86/kaslr: Reduce KASLR entropy on most x86 systems, to support PCI BAR space beyond the 10TiB region (CONFIG_PCI_P2PDMA=y) (Balbir Singh) CPU bugs: - Implement FineIBT-BHI mitigation (Peter Zijlstra) - speculation: Simplify and make CALL_NOSPEC consistent (Pawan Gupta) - speculation: Add a conditional CS prefix to CALL_NOSPEC (Pawan Gupta) - RFDS: Exclude P-only parts from the RFDS affected list (Pawan Gupta) System calls: - Break up entry/common.c (Brian Gerst) - Move sysctls into arch/x86 (Joel Granados) Intel LAM support updates: (Maciej Wieczor-Retman) - selftests/lam: Move cpu_has_la57() to use cpuinfo flag - selftests/lam: Skip test if LAM is disabled - selftests/lam: Test get_user() LAM pointer handling AMD SMN access updates: - Add SMN offsets to exclusive region access (Mario Limonciello) - Add support for debugfs access to SMN registers (Mario Limonciello) - Have HSMP use SMN through AMD_NODE (Yazen Ghannam) Power management updates: (Patryk Wlazlyn) - Allow calling mwait_play_dead with an arbitrary hint - ACPI/processor_idle: Add FFH state handling - intel_idle: Provide the default enter_dead() handler - Eliminate mwait_play_dead_cpuid_hint() Build system: - Raise the minimum GCC version to 8.1 (Brian Gerst) - Raise the minimum LLVM version to 15.0.0 (Nathan Chancellor) Kconfig: (Arnd Bergmann) - Add cmpxchg8b support back to Geode CPUs - Drop 32-bit "bigsmp" machine support - Rework CONFIG_GENERIC_CPU compiler flags - Drop configuration options for early 64-bit CPUs - Remove CONFIG_HIGHMEM64G support - Drop CONFIG_SWIOTLB for PAE - Drop support for CONFIG_HIGHPTE - Document CONFIG_X86_INTEL_MID as 64-bit-only - Remove old STA2x11 support - Only allow CONFIG_EISA for 32-bit Headers: - Replace __ASSEMBLY__ with __ASSEMBLER__ in UAPI and non-UAPI headers (Thomas Huth) Assembly code & machine code patching: - x86/alternatives: Simplify alternative_call() interface (Josh Poimboeuf) - x86/alternatives: Simplify callthunk patching (Peter Zijlstra) - KVM: VMX: Use named operands in inline asm (Josh Poimboeuf) - x86/hyperv: Use named operands in inline asm (Josh Poimboeuf) - x86/traps: Cleanup and robustify decode_bug() (Peter Zijlstra) - x86/kexec: Merge x86_32 and x86_64 code using macros from (Uros Bizjak) - Use named operands in inline asm (Uros Bizjak) - Improve performance by using asm_inline() for atomic locking instructions (Uros Bizjak) Earlyprintk: - Harden early_serial (Peter Zijlstra) NMI handler: - Add an emergency handler in nmi_desc & use it in nmi_shootdown_cpus() (Waiman Long) Miscellaneous fixes and cleanups: - by Ahmed S. Darwish, Andy Shevchenko, Ard Biesheuvel, Artem Bityutskiy, Borislav Petkov, Brendan Jackman, Brian Gerst, Dan Carpenter, Dr. David Alan Gilbert, H. Peter Anvin, Ingo Molnar, Josh Poimboeuf, Kevin Brodsky, Mike Rapoport, Lukas Bulwahn, Maciej Wieczor-Retman, Max Grobecker, Patryk Wlazlyn, Pawan Gupta, Peter Zijlstra, Philip Redkin, Qasim Ijaz, Rik van Riel, Thomas Gleixner, Thorsten Blum, Tom Lendacky, Tony Luck, Uros Bizjak, Vitaly Kuznetsov, Xin Li, liuye" * tag 'x86-core-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (211 commits) zstd: Increase DYNAMIC_BMI2 GCC version cutoff from 4.8 to 11.0 to work around compiler segfault x86/asm: Make asm export of __ref_stack_chk_guard unconditional x86/mm: Only do broadcast flush from reclaim if pages were unmapped perf/x86/intel, x86/cpu: Replace Pentium 4 model checks with VFM ones perf/x86/intel, x86/cpu: Simplify Intel PMU initialization x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-UAPI headers x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in UAPI headers x86/locking/atomic: Improve performance by using asm_inline() for atomic locking instructions x86/asm: Use asm_inline() instead of asm() in clwb() x86/asm: Use CLFLUSHOPT and CLWB mnemonics in x86/hweight: Use asm_inline() instead of asm() x86/hweight: Use ASM_CALL_CONSTRAINT in inline asm() x86/hweight: Use named operands in inline asm() x86/stackprotector/64: Only export __ref_stack_chk_guard on CONFIG_SMP x86/head/64: Avoid Clang < 17 stack protector in startup code x86/kexec: Merge x86_32 and x86_64 code using macros from x86/runtime-const: Add the RUNTIME_CONST_PTR assembly macro x86/cpu/intel: Limit the non-architectural constant_tsc model checks x86/mm/pat: Replace Intel x86_model checks with VFM ones x86/cpu/intel: Fix fast string initialization for extended Families ...

objtool/LoongArch: Add support for goto table

2025-03-12T22:43:39Z

The objtool program need to analysis the control flow of each object file generated by compiler toolchain, it needs to know all the locations that a branch instruction may jump into, if a jump table is used, objtool has to correlate the jump instruction with the table. On x86 (which is the only port supported by objtool before LoongArch), there is a relocation type on the jump instruction and directly points to the table. But on LoongArch, the relocation is on another kind of instruction prior to the jump instruction, and also with scheduling it is not very easy to tell the offset of that instruction from the jump instruction. Furthermore, because LoongArch has -fsection-anchors (often enabled at -O1 or above) the relocation may actually points to a section anchor instead of the table itself. For the jump table of switch cases, a GCC patch "LoongArch: Add support to annotate tablejump" and a Clang patch "[LoongArch] Add options for annotate tablejump" have been merged into the upstream mainline, it can parse the additional section ".discard.tablejump_annotate" which stores the jump info as pairs of addresses, each pair contains the address of jump instruction and the address of jump table. For the jump table of computed gotos, it is indeed not easy to implement in the compiler, especially if there is more than one computed goto in a function such as ___bpf_prog_run(). objdump kernel/bpf/core.o shows that there are many table jump instructions in ___bpf_prog_run(), but there are no relocations on the table jump instructions and to the table directly on LoongArch. Without the help of compiler, in order to figure out the address of goto table for the special case of ___bpf_prog_run(), since the instruction sequence is relatively single and stable, it makes sense to add a helper find_reloc_of_rodata_c_jump_table() to find the relocation which points to the section ".rodata..c_jump_table". If find_reloc_by_table_annotate() failed, it means there is no relocation info of switch table address in ".rela.discard.tablejump_annotate", then objtool may find the relocation info of goto table ".rodata..c_jump_table" with find_reloc_of_rodata_c_jump_table(). Signed-off-by: Tiezhu Yang Link: https://lore.kernel.org/r/20250211115016.26913-6-yangtiezhu@loongson.cn Acked-by: Huacai Chen Signed-off-by: Josh Poimboeuf