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2026-04-22x86-64: rename misleadingly named '__copy_user_nocache()' functionLinus Torvalds1-1/+1
commit d187a86de793f84766ea40b9ade7ac60aabbb4fe upstream. This function was a masterclass in bad naming, for various historical reasons. It claimed to be a non-cached user copy. It is literally _neither_ of those things. It's a specialty memory copy routine that uses non-temporal stores for the destination (but not the source), and that does exception handling for both source and destination accesses. Also note that while it works for unaligned targets, any unaligned parts (whether at beginning or end) will not use non-temporal stores, since only words and quadwords can be non-temporal on x86. The exception handling means that it _can_ be used for user space accesses, but not on its own - it needs all the normal "start user space access" logic around it. But typically the user space access would be the source, not the non-temporal destination. That was the original intention of this, where the destination was some fragile persistent memory target that needed non-temporal stores in order to catch machine check exceptions synchronously and deal with them gracefully. Thus that non-descriptive name: one use case was to copy from user space into a non-cached kernel buffer. However, the existing users are a mix of that intended use-case, and a couple of random drivers that just did this as a performance tweak. Some of those random drivers then actively misused the user copying version (with STAC/CLAC and all) to do kernel copies without ever even caring about the exception handling, _just_ for the non-temporal destination. Rename it as a first small step to actually make it halfway sane, and change the prototype to be more normal: it doesn't take a user pointer unless the caller has done the proper conversion, and the argument size is the full size_t (it still won't actually copy more than 4GB in one go, but there's also no reason to silently truncate the size argument in the caller). Finally, use this now sanely named function in the NTB code, which mis-used a user copy version (with STAC/CLAC and all) of this interface despite it not actually being a user copy at all. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-04-11objtool: Fix Clang jump table detectionJosh Poimboeuf1-3/+2
[ Upstream commit 4e5019216402ad0b4a84cff457b662d26803f103 ] With Clang, there can be a conditional forward jump between the load of the jump table address and the indirect branch. Fixes the following warning: vmlinux.o: warning: objtool: ___bpf_prog_run+0x1c5: sibling call from callable instruction with modified stack frame Reported-by: Arnd Bergmann <arnd@arndb.de> Closes: https://lore.kernel.org/a426d669-58bb-4be1-9eaa-6f3d83109e2d@app.fastmail.com Link: https://patch.msgid.link/7d8600caed08901b6679767488acd639f6df9688.1773071992.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-04-02objtool: Handle Clang RSP musical chairsJosh Poimboeuf2-39/+37
[ 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 <arnd@arndb.de> 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 <jpoimboe@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-19kbuild: Leave objtool binary around with 'make clean'Nathan Chancellor1-3/+5
[ Upstream commit fdb12c8a24a453bdd6759979b6ef1e04ebd4beb4 ] The difference between 'make clean' and 'make mrproper' is documented in 'make help' as: clean - Remove most generated files but keep the config and enough build support to build external modules mrproper - Remove all generated files + config + various backup files After commit 68b4fe32d737 ("kbuild: Add objtool to top-level clean target"), running 'make clean' then attempting to build an external module with the resulting build directory fails with $ make ARCH=x86_64 O=build clean $ make -C build M=... MO=... ... /bin/sh: line 1: .../build/tools/objtool/objtool: No such file or directory as 'make clean' removes the objtool binary. Split the objtool clean target into mrproper and clean like Kbuild does and remove all generated artifacts with 'make clean' except for the objtool binary, which is removed with 'make mrproper'. To avoid a small race when running the objtool clean target through both objtool_mrproper and objtool_clean when running 'make mrproper', modify objtool's clean up find command to avoid using find's '-delete' command by piping the files into 'xargs rm -f' like the rest of Kbuild does. Cc: stable@vger.kernel.org Fixes: 68b4fe32d737 ("kbuild: Add objtool to top-level clean target") Reported-by: Michal Suchanek <msuchanek@suse.de> Closes: https://lore.kernel.org/20260225112633.6123-1-msuchanek@suse.de/ Reported-by: Rainer Fiebig <jrf@mailbox.org> Closes: https://lore.kernel.org/62d12399-76e5-3d40-126a-7490b4795b17@mailbox.org/ Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Nicolas Schier <nsc@kernel.org> Tested-by: Nicolas Schier <nsc@kernel.org> Link: https://patch.msgid.link/20260227-avoid-objtool-binary-removal-clean-v1-1-122f3e55eae9@kernel.org Signed-off-by: Nathan Chancellor <nathan@kernel.org> [ Context ] Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-02-26kbuild: Add objtool to top-level clean targetJosh Poimboeuf1-0/+2
[ Upstream commit 68b4fe32d73789dea23e356f468de67c8367ef8f ] Objtool is an integral part of the build, make sure it gets cleaned by "make clean" and "make mrproper". Fixes: 442f04c34a1a ("objtool: Add tool to perform compile-time stack metadata validation") Reported-by: Jens Remus <jremus@linux.ibm.com> Closes: https://lore.kernel.org/15f2af3b-be33-46fc-b972-6b8e7e0aa52e@linux.ibm.com Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Tested-by: Jens Remus <jremus@linux.ibm.com> Link: https://patch.msgid.link/968faf2ed30fa8b3519f79f01a1ecfe7929553e5.1770759919.git.jpoimboe@kernel.org [nathan: use Closes: instead of Link: per checkpatch.pl] Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-18objtool: Fix weak symbol detectionJosh Poimboeuf1-4/+4
[ Upstream commit 72567c630d32bc31f671977f78228c80937ed80e ] find_symbol_hole_containing() fails to find a symbol hole (aka stripped weak symbol) if its section has no symbols before the hole. This breaks weak symbol detection if -ffunction-sections is enabled. Fix that by allowing the interval tree to contain section symbols, which are always at offset zero for a given section. Fixes a bunch of (-ffunction-sections) warnings like: vmlinux.o: warning: objtool: .text.__x64_sys_io_setup+0x10: unreachable instruction Fixes: 4adb23686795 ("objtool: Ignore extra-symbol code") Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-12-18objtool: Fix standalone --hacks=jump_labelDylan Hatch1-1/+2
[ Upstream commit be8374a5ba7cbab6b97df94b4ffe0b92f5c8a6d2 ] The objtool command line 'objtool --hacks=jump_label foo.o' on its own should be expected to rewrite jump labels to NOPs. This means the add_special_section_alts() code path needs to run when only this option is provided. This is mainly relevant in certain debugging situations, but could potentially also fix kernel builds in which objtool is run with --hacks=jump_label but without --orc, --stackval, --uaccess, or --hacks=noinstr. Fixes: de6fbcedf5ab ("objtool: Read special sections with alts only when specific options are selected") Signed-off-by: Dylan Hatch <dylanbhatch@google.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-11-01objtool: Fix skip_alt_group() for non-alternative STAC/CLACJosh Poimboeuf1-1/+4
If an insn->alt points to a STAC/CLAC instruction, skip_alt_group() assumes it's part of an alternative ("alt group") as opposed to some other kind of "alt" such as an exception fixup. While that assumption may hold true in the current code base, Linus has an out-of-tree patch which breaks that assumption by replacing the STAC/CLAC alternatives with raw STAC/CLAC instructions. Make skip_alt_group() more robust by making sure it's actually an alt group before continuing. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Fixes: 2d12c6fb7875 ("objtool: Remove ANNOTATE_IGNORE_ALTERNATIVE from CLAC/STAC") Closes: https://lore.kernel.org/CAHk-=wi6goUT36sR8GE47_P-aVrd5g38=VTRHpktWARbyE-0ow@mail.gmail.com Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Linus Torvalds <torvalds@linux-foundation.org> Link: https://patch.msgid.link/3d22415f7b8e06a64e0873b21f48389290eeaa49.1761767616.git.jpoimboe@kernel.org
2025-10-22objtool: Fix failure when being compiled on x32 systemMikulas Patocka1-2/+2
Fix compilation failure when compiling the kernel with the x32 toolchain. In file included from check.c:16: check.c: In function ¡check_abs_references¢: /usr/src/git/linux-2.6/tools/objtool/include/objtool/warn.h:47:17: error: format ¡%lx¢ expects argument of type ¡long unsigned int¢, but argument 7 has type ¡u64¢ {aka ¡long long unsigned int¢} [-Werror=format=] 47 | "%s%s%s: objtool" extra ": " format "\n", \ | ^~~~~~~~~~~~~~~~~ /usr/src/git/linux-2.6/tools/objtool/include/objtool/warn.h:54:9: note: in expansion of macro ¡___WARN¢ 54 | ___WARN(severity, "", format, ##__VA_ARGS__) | ^~~~~~~ /usr/src/git/linux-2.6/tools/objtool/include/objtool/warn.h:74:27: note: in expansion of macro ¡__WARN¢ 74 | #define WARN(format, ...) __WARN(WARN_STR, format, ##__VA_ARGS__) | ^~~~~~ check.c:4713:33: note: in expansion of macro ¡WARN¢ 4713 | WARN("section %s has absolute relocation at offset 0x%lx", | ^~~~ Fixes: 0d6e4563fc03 ("objtool: Add action to check for absence of absolute relocations") Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://patch.msgid.link/1ac32fff-2e67-5155-f570-69aad5bf5412@redhat.com
2025-10-22objtool/rust: add one more `noreturn` Rust functionMiguel Ojeda1-0/+1
Between Rust 1.79 and 1.86, under `CONFIG_RUST_KERNEL_DOCTESTS=y`, `objtool` may report: rust/doctests_kernel_generated.o: warning: objtool: rust_doctest_kernel_alloc_kbox_rs_13() falls through to next function rust_doctest_kernel_alloc_kvec_rs_0() (as well as in rust_doctest_kernel_alloc_kvec_rs_0) due to calls to the `noreturn` symbol: core::option::expect_failed from code added in commits 779db37373a3 ("rust: alloc: kvec: implement AsPageIter for VVec") and 671618432f46 ("rust: alloc: kbox: implement AsPageIter for VBox"). Thus add the mangled one to the list so that `objtool` knows it is actually `noreturn`. This can be reproduced as well in other versions by tweaking the code, such as the latest stable Rust (1.90.0). Stable does not have code that triggers this, but it could have it in the future. Downstream forks could too. Thus tag it for backport. See commit 56d680dd23c3 ("objtool/rust: list `noreturn` Rust functions") for more details. Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Cc: stable@vger.kernel.org # Needed in 6.12.y and later. Link: https://patch.msgid.link/20251020020714.2511718-1-ojeda@kernel.org
2025-10-11Merge tag 'x86_core_for_v6.18_rc1' of ↵Linus Torvalds2-0/+43
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull more x86 updates from Borislav Petkov: - Remove a bunch of asm implementing condition flags testing in KVM's emulator in favor of int3_emulate_jcc() which is written in C - Replace KVM fastops with C-based stubs which avoids problems with the fastop infra related to latter not adhering to the C ABI due to their special calling convention and, more importantly, bypassing compiler control-flow integrity checking because they're written in asm - Remove wrongly used static branches and other ugliness accumulated over time in hyperv's hypercall implementation with a proper static function call to the correct hypervisor call variant - Add some fixes and modifications to allow running FRED-enabled kernels in KVM even on non-FRED hardware - Add kCFI improvements like validating indirect calls and prepare for enabling kCFI with GCC. Add cmdline params documentation and other code cleanups - Use the single-byte 0xd6 insn as the official #UD single-byte undefined opcode instruction as agreed upon by both x86 vendors - Other smaller cleanups and touchups all over the place * tag 'x86_core_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) x86,retpoline: Optimize patch_retpoline() x86,ibt: Use UDB instead of 0xEA x86/cfi: Remove __noinitretpoline and __noretpoline x86/cfi: Add "debug" option to "cfi=" bootparam x86/cfi: Standardize on common "CFI:" prefix for CFI reports x86/cfi: Document the "cfi=" bootparam options x86/traps: Clarify KCFI instruction layout compiler_types.h: Move __nocfi out of compiler-specific header objtool: Validate kCFI calls x86/fred: KVM: VMX: Always use FRED for IRQs when CONFIG_X86_FRED=y x86/fred: Play nice with invoking asm_fred_entry_from_kvm() on non-FRED hardware x86/fred: Install system vector handlers even if FRED isn't fully enabled x86/hyperv: Use direct call to hypercall-page x86/hyperv: Clean up hv_do_hypercall() KVM: x86: Remove fastops KVM: x86: Convert em_salc() to C KVM: x86: Introduce EM_ASM_3WCL KVM: x86: Introduce EM_ASM_1SRC2 KVM: x86: Introduce EM_ASM_2CL KVM: x86: Introduce EM_ASM_2W ...
2025-10-01Merge tag 'kbuild-6.18-1' of ↵Linus Torvalds1-10/+0
git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux Pull Kbuild updates from Nathan Chancellor: - Extend modules.builtin.modinfo to include module aliases from MODULE_DEVICE_TABLE for builtin modules so that userspace tools (such as kmod) can verify that a particular module alias will be handled by a builtin module - Bump the minimum version of LLVM for building the kernel to 15.0.0 - Upgrade several userspace API checks in headers_check.pl to errors - Unify and consolidate CONFIG_WERROR / W=e handling - Turn assembler and linker warnings into errors with CONFIG_WERROR / W=e - Respect CONFIG_WERROR / W=e when building userspace programs (userprogs) - Enable -Werror unconditionally when building host programs (hostprogs) - Support copy_file_range() and data segment alignment in gen_init_cpio to improve performance on filesystems that support reflinks such as btrfs and XFS - Miscellaneous small changes to scripts and configuration files * tag 'kbuild-6.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux: (47 commits) modpost: Initialize builtin_modname to stop SIGSEGVs Documentation: kbuild: note CONFIG_DEBUG_EFI in reproducible builds kbuild: vmlinux.unstripped should always depend on .vmlinux.export.o modpost: Create modalias for builtin modules modpost: Add modname to mod_device_table alias scsi: Always define blogic_pci_tbl structure kbuild: extract modules.builtin.modinfo from vmlinux.unstripped kbuild: keep .modinfo section in vmlinux.unstripped kbuild: always create intermediate vmlinux.unstripped s390: vmlinux.lds.S: Reorder sections KMSAN: Remove tautological checks objtool: Drop noinstr hack for KCSAN_WEAK_MEMORY lib/Kconfig.debug: Drop CLANG_VERSION check from DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT riscv: Remove ld.lld version checks from many TOOLCHAIN_HAS configs riscv: Unconditionally use linker relaxation riscv: Remove version check for LTO_CLANG selects powerpc: Drop unnecessary initializations in __copy_inst_from_kernel_nofault() mips: Unconditionally select ARCH_HAS_CURRENT_STACK_POINTER arm64: Remove tautological LLVM Kconfig conditions ARM: Clean up definition of ARM_HAS_GROUP_RELOCS ...
2025-09-30Merge tag 'x86_apic_for_v6.18_rc1' of ↵Linus Torvalds6-2/+63
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 SEV and apic updates from Borislav Petkov: - Add functionality to provide runtime firmware updates for the non-x86 parts of an AMD platform like the security processor (ASP) firmware, modules etc, for example. The intent being that these updates are interim, live fixups before a proper BIOS update can be attempted - Add guest support for AMD's Secure AVIC feature which gives encrypted guests the needed protection against a malicious hypervisor generating unexpected interrupts and injecting them into such guest, thus interfering with its operation in an unexpected and negative manner. The advantage of this scheme is that the guest determines which interrupts and when to accept them vs leaving that to the benevolence (or not) of the hypervisor - Strictly separate the startup code from the rest of the kernel where former is executed from the initial 1:1 mapping of memory. The problem was that the toolchain-generated version of the code was being executed from a different mapping of memory than what was "assumed" during code generation, needing an ever-growing pile of fixups for absolute memory references which are invalid in the early, 1:1 memory mapping during boot. The major advantage of this is that there's no need to check the 1:1 mapping portion of the code for absolute relocations anymore and get rid of the RIP_REL_REF() macro sprinkling all over the place. For more info, see Ard's very detailed writeup on this [1] - The usual cleanups and fixes Link: https://lore.kernel.org/r/CAMj1kXEzKEuePEiHB%2BHxvfQbFz0sTiHdn4B%2B%2BzVBJ2mhkPkQ4Q@mail.gmail.com [1] * tag 'x86_apic_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (49 commits) x86/boot: Drop erroneous __init annotation from early_set_pages_state() crypto: ccp - Add AMD Seamless Firmware Servicing (SFS) driver crypto: ccp - Add new HV-Fixed page allocation/free API x86/sev: Add new dump_rmp parameter to snp_leak_pages() API x86/startup/sev: Document the CPUID flow in the boot #VC handler objtool: Ignore __pi___cfi_ prefixed symbols x86/sev: Zap snp_abort() x86/apic/savic: Do not use snp_abort() x86/boot: Get rid of the .head.text section x86/boot: Move startup code out of __head section efistub/x86: Remap inittext read-execute when needed x86/boot: Create a confined code area for startup code x86/kbuild: Incorporate boot/startup/ via Kbuild makefile x86/boot: Revert "Reject absolute references in .head.text" x86/boot: Check startup code for absence of absolute relocations objtool: Add action to check for absence of absolute relocations x86/sev: Export startup routines for later use x86/sev: Move __sev_[get|put]_ghcb() into separate noinstr object x86/sev: Provide PIC aliases for SEV related data objects x86/boot: Provide PIC aliases for 5-level paging related constants ...
2025-09-19Merge 6.17-rc6 into kbuild-nextNathan Chancellor1-0/+23
Commit bd7c2312128e ("pinctrl: meson: Fix typo in device table macro") is needed in kbuild-next to avoid a build error with a future change. While at it, address the conflict between commit 41f9049cff32 ("riscv: Only allow LTO with CMODEL_MEDANY") and commit 6578a1ff6aa4 ("riscv: Remove version check for LTO_CLANG selects"), as reported by Stephen Rothwell [1]. Link: https://lore.kernel.org/20250908134913.68778b7b@canb.auug.org.au/ [1] Signed-off-by: Nathan Chancellor <nathan@kernel.org>
2025-09-18objtool/LoongArch: Mark special atomic instruction as INSN_BUG typeTiezhu Yang1-0/+21
When compiling with LLVM and CONFIG_RUST is set, there exists the following objtool warning: rust/compiler_builtins.o: warning: objtool: __rust__unordsf2(): unexpected end of section .text.unlikely. objdump shows that the end of section .text.unlikely is an atomic instruction: amswap.w $zero, $ra, $zero According to the LoongArch Reference Manual, if the amswap.w atomic memory access instruction has the same register number as rd and rj, the execution will trigger an Instruction Non-defined Exception, so mark the above instruction as INSN_BUG type to fix the warning. Cc: stable@vger.kernel.org Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2025-09-18objtool/LoongArch: Mark types based on break immediate codeTiezhu Yang1-3/+9
If the break immediate code is 0, it should mark the type as INSN_TRAP. If the break immediate code is 1, it should mark the type as INSN_BUG. While at it, format the code style and add the code comment for nop. Cc: stable@vger.kernel.org Suggested-by: WANG Rui <wangrui@loongson.cn> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2025-09-09objtool: Ignore __pi___cfi_ prefixed symbolsNathan Chancellor1-0/+1
When building with CONFIG_CFI_CLANG=y after the recent series to separate the x86 startup code, there are objtool warnings along the lines of: vmlinux.o: warning: objtool: __pi___cfi_startup_64_load_idt() falls through to next function __pi_startup_64_load_idt() vmlinux.o: warning: objtool: __pi___cfi_startup_64_setup_gdt_idt() falls through to next function __pi_startup_64_setup_gdt_idt() vmlinux.o: warning: objtool: __pi___cfi___startup_64() falls through to next function __pi___startup_64() As the comment in validate_branch() states, this is expected, so ignore these symbols in the same way that __cfi_ and __pfx_ symbols are already ignored for the rest of the kernel. Fixes: 7b38dec3c5af ("x86/boot: Create a confined code area for startup code") Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Acked-by: Ard Biesheuvel <ardb@kernel.org>
2025-09-04x86/sev: Zap snp_abort()Borislav Petkov (AMD)1-1/+0
It is a silly oneliner anyway. Replace it with its equivalent. No functional changes. Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
2025-09-03x86/boot: Create a confined code area for startup codeArd Biesheuvel1-1/+2
In order to be able to have tight control over which code may execute from the early 1:1 mapping of memory, but still link vmlinux as a single executable, prefix all symbol references in startup code with __pi_, and invoke it from outside using the __pi_ prefix. Use objtool to check that no absolute symbol references are present in the startup code, as these cannot be used from code running from the 1:1 mapping. Note that this also requires disabling the latent-entropy GCC plugin, as the global symbol references that it injects would require explicit exports, and given that the startup code rarely executes more than once, it is not a useful source of entropy anyway. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/20250828102202.1849035-43-ardb+git@google.com
2025-09-03objtool: Add action to check for absence of absolute relocationsArd Biesheuvel5-0/+60
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 <ardb@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/20250828102202.1849035-39-ardb+git@google.com
2025-08-28objtool: Drop noinstr hack for KCSAN_WEAK_MEMORYNathan Chancellor1-10/+0
Now that the minimum supported version of LLVM for building the kernel has been bumped to 15.0.0, __no_kcsan will always ensure that the thread sanitizer functions are not generated, so remove the check for tsan functions in is_profiling_func() and the always true depends and unnecessary select lines in KCSAN_WEAK_MEMORY. Acked-by: Marco Elver <elver@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infraded.org> Reviewed-by: Kees Cook <kees@kernel.org> Link: https://lore.kernel.org/r/20250821-bump-min-llvm-ver-15-v2-11-635f3294e5f0@kernel.org Signed-off-by: Nathan Chancellor <nathan@kernel.org>
2025-08-20objtool/LoongArch: Get table size correctly if LTO is enabledTiezhu Yang1-0/+23
When compiling with LLVM and CONFIG_LTO_CLANG is set, there exist many objtool warnings "sibling call from callable instruction with modified stack frame". For this special case, the related object file shows that there is no generated relocation section '.rela.discard.tablejump_annotate' for the table jump instruction jirl, thus objtool can not know that what is the actual destination address. It needs to do something on the LLVM side to make sure that there is the relocation section '.rela.discard.tablejump_annotate' if LTO is enabled, but in order to maintain compatibility for the current LLVM compiler, this can be done in the kernel Makefile for now. Ensure it is aware of linker with LTO, '--loongarch-annotate-tablejump' needs to be passed via '-mllvm' to ld.lld. Before doing the above changes, it should handle the special case of the relocation section '.rela.discard.tablejump_annotate' to get the correct table size first, otherwise there are many objtool warnings and errors if LTO is enabled. There are many different rodata for each function if LTO is enabled, it is necessary to enhance get_rodata_table_size_by_table_annotate(). Fixes: b95f852d3af2 ("objtool/LoongArch: Add support for switch table") Closes: https://lore.kernel.org/loongarch/20250731175655.GA1455142@ax162/ Reported-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2025-08-18objtool: Validate kCFI callsPeter Zijlstra2-0/+43
Validate that all indirect calls adhere to kCFI rules. Notably doing nocfi indirect call to a cfi function is broken. Apparently some Rust 'core' code violates this and explodes when ran with FineIBT. All the ANNOTATE_NOCFI_SYM sites are prime targets for attackers. - runtime EFI is especially henous because it also needs to disable IBT. Basically calling unknown code without CFI protection at runtime is a massice security issue. - Kexec image handover; if you can exploit this, you get to keep it :-) Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Acked-by: Sean Christopherson <seanjc@google.com> Link: https://lkml.kernel.org/r/20250714103441.496787279@infradead.org
2025-07-30Merge tag 'trace-rv-6.17' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull runtime verification updates from Steven Rostedt: - Added Linear temporal logic monitors for RT application Real-time applications may have design flaws causing them to have unexpected latency. For example, the applications may raise page faults, or may be blocked trying to take a mutex without priority inheritance. However, while attempting to implement DA monitors for these real-time rules, deterministic automaton is found to be inappropriate as the specification language. The automaton is complicated, hard to understand, and error-prone. For these cases, linear temporal logic is found to be more suitable. The LTL is more concise and intuitive. - Make printk_deferred() public The new monitors needed access to printk_deferred(). Make them visible for the entire kernel. - Add a vpanic() to allow for va_list to be passed to panic. - Add rtapp container monitor. A collection of monitors that check for common problems with real-time applications that cause unexpected latency. - Add page fault tracepoints to risc-v These tracepoints are necessary to for the RV monitor to run on risc-v. - Fix the behaviour of the rv tool with -s and idle tasks. - Allow the rv tool to gracefully terminate with SIGTERM - Adjusts dot2c not to create lines over 100 columns - Properly order nested monitors in the RV Kconfig file - Return the registration error in all DA monitor instead of 0 - Update and add new sched collection monitors Replace tss and sncid monitors with more complete sts: Not only prove that switches occur in scheduling context and scheduling needs interrupt disabled but also that each call to the scheduler disables interrupts to (optionally) switch. New monitor: nrp Preemption requires need resched which is cleared by any switch (includes a non optimal workaround for /nested/ preemptions) New monitor: sssw suspension requires setting the task to sleepable and, after the switch occurs, the task requires a wakeup to come back to runnable New monitor: opid waking and need-resched operations occur with interrupts and preemption disabled or in IRQ without explicitly disabling preemption" * tag 'trace-rv-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (48 commits) rv: Add opid per-cpu monitor rv: Add nrp and sssw per-task monitors rv: Replace tss and sncid monitors with more complete sts sched: Adapt sched tracepoints for RV task model rv: Retry when da monitor detects race conditions rv: Adjust monitor dependencies rv: Use strings in da monitors tracepoints rv: Remove trailing whitespace from tracepoint string rv: Add da_handle_start_run_event_ to per-task monitors rv: Fix wrong type cast in reactors_show() and monitor_reactor_show() rv: Fix wrong type cast in monitors_show() rv: Remove struct rv_monitor::reacting rv: Remove rv_reactor's reference counter rv: Merge struct rv_reactor_def into struct rv_reactor rv: Merge struct rv_monitor_def into struct rv_monitor rv: Remove unused field in struct rv_monitor_def rv: Return init error when registering monitors verification/rvgen: Organise Kconfig entries for nested monitors tools/dot2c: Fix generated files going over 100 column limit tools/rv: Stop gracefully also on SIGTERM ...
2025-07-28Merge tag 'hardening-v6.17-rc1' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull hardening updates from Kees Cook: - Introduce and start using TRAILING_OVERLAP() helper for fixing embedded flex array instances (Gustavo A. R. Silva) - mux: Convert mux_control_ops to a flex array member in mux_chip (Thorsten Blum) - string: Group str_has_prefix() and strstarts() (Andy Shevchenko) - Remove KCOV instrumentation from __init and __head (Ritesh Harjani, Kees Cook) - Refactor and rename stackleak feature to support Clang - Add KUnit test for seq_buf API - Fix KUnit fortify test under LTO * tag 'hardening-v6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (22 commits) sched/task_stack: Add missing const qualifier to end_of_stack() kstack_erase: Support Clang stack depth tracking kstack_erase: Add -mgeneral-regs-only to silence Clang warnings init.h: Disable sanitizer coverage for __init and __head kstack_erase: Disable kstack_erase for all of arm compressed boot code x86: Handle KCOV __init vs inline mismatches arm64: Handle KCOV __init vs inline mismatches s390: Handle KCOV __init vs inline mismatches arm: Handle KCOV __init vs inline mismatches mips: Handle KCOV __init vs inline mismatch powerpc/mm/book3s64: Move kfence and debug_pagealloc related calls to __init section configs/hardening: Enable CONFIG_INIT_ON_FREE_DEFAULT_ON configs/hardening: Enable CONFIG_KSTACK_ERASE stackleak: Split KSTACK_ERASE_CFLAGS from GCC_PLUGINS_CFLAGS stackleak: Rename stackleak_track_stack to __sanitizer_cov_stack_depth stackleak: Rename STACKLEAK to KSTACK_ERASE seq_buf: Introduce KUnit tests string: Group str_has_prefix() and strstarts() kunit/fortify: Add back "volatile" for sizeof() constants acpi: nfit: intel: avoid multiple -Wflex-array-member-not-at-end warnings ...
2025-07-21stackleak: Rename stackleak_track_stack to __sanitizer_cov_stack_depthKees Cook1-1/+1
The Clang stack depth tracking implementation has a fixed name for the stack depth tracking callback, "__sanitizer_cov_stack_depth", so rename the GCC plugin function to match since the plugin has no external dependencies on naming. Link: https://lore.kernel.org/r/20250717232519.2984886-2-kees@kernel.org Signed-off-by: Kees Cook <kees@kernel.org>
2025-07-21stackleak: Rename STACKLEAK to KSTACK_ERASEKees Cook1-1/+1
In preparation for adding Clang sanitizer coverage stack depth tracking that can support stack depth callbacks: - Add the new top-level CONFIG_KSTACK_ERASE option which will be implemented either with the stackleak GCC plugin, or with the Clang stack depth callback support. - Rename CONFIG_GCC_PLUGIN_STACKLEAK as needed to CONFIG_KSTACK_ERASE, but keep it for anything specific to the GCC plugin itself. - Rename all exposed "STACKLEAK" names and files to "KSTACK_ERASE" (named for what it does rather than what it protects against), but leave as many of the internals alone as possible to avoid even more churn. While here, also split "prev_lowest_stack" into CONFIG_KSTACK_ERASE_METRICS, since that's the only place it is referenced from. Suggested-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20250717232519.2984886-1-kees@kernel.org Signed-off-by: Kees Cook <kees@kernel.org>
2025-07-19Merge tag 'rust-fixes-6.16-2' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux Pull Rust fixes from Miguel Ojeda: "Toolchain and infrastructure: - Fix build and modpost confusion for the upcoming Rust 1.89.0 release - Clean objtool warning for the upcoming Rust 1.89.0 release by adding one more noreturn function 'kernel' crate: - Fix build error when using generics in the 'try_{,pin_}init!' macros" * tag 'rust-fixes-6.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: rust: use `#[used(compiler)]` to fix build and `modpost` with Rust >= 1.89.0 objtool/rust: add one more `noreturn` Rust function for Rust 1.89.0 rust: init: Fix generics in *_init! macros
2025-07-14objtool/rust: add one more `noreturn` Rust function for Rust 1.89.0Miguel Ojeda1-0/+1
Starting with Rust 1.89.0 (expected 2025-08-07), under `CONFIG_RUST_DEBUG_ASSERTIONS=y`, `objtool` may report: rust/kernel.o: warning: objtool: _R..._6kernel4pageNtB5_4Page8read_raw() falls through to next function _R..._6kernel4pageNtB5_4Page9write_raw() (and many others) due to calls to the `noreturn` symbol: core::panicking::panic_nounwind_fmt Thus add the mangled one to the list so that `objtool` knows it is actually `noreturn`. See commit 56d680dd23c3 ("objtool/rust: list `noreturn` Rust functions") for more details. Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs). Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20250712160103.1244945-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-07-11objtool: Add vpanic() to the noreturn listNam Cao1-0/+1
vpanic() does not return. However, objtool doesn't know this and gets confused: kernel/trace/rv/reactor_panic.o: warning: objtool: rv_panic_reaction(): unexpected end of section .text Add vpanic() to the list of noreturn functions. Cc: John Ogness <john.ogness@linutronix.de> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Gabriele Monaco <gmonaco@redhat.com> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/073f826ebec18b2bb59cba88606cd865d8039fd2.1752232374.git.namcao@linutronix.de Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202507110826.2ekbVdWZ-lkp@intel.com/ Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Nam Cao <namcao@linutronix.de> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-01objtool: Add missing endian conversion to read_annotate()Heiko Carstens1-0/+1
Trying to compile an x86 kernel on big endian results in this error: net/ipv4/netfilter/iptable_nat.o: warning: objtool: iptable_nat_table_init+0x150: Unknown annotation type: 50331648 make[5]: *** [scripts/Makefile.build:287: net/ipv4/netfilter/iptable_nat.o] Error 255 Reason is a missing endian conversion in read_annotate(). Add the missing conversion to fix this. Fixes: 2116b349e29a ("objtool: Generic annotation infrastructure") Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20250630131230.4130185-1-hca@linux.ibm.com
2025-06-04Merge tag 'rust-6.16' of ↵Linus Torvalds1-1/+2
git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux Pull Rust updates from Miguel Ojeda: "Toolchain and infrastructure: - KUnit '#[test]'s: - Support KUnit-mapped 'assert!' macros. The support that landed last cycle was very basic, and the 'assert!' macros panicked since they were the standard library ones. Now, they are mapped to the KUnit ones in a similar way to how is done for doctests, reusing the infrastructure there. With this, a failing test like: #[test] fn my_first_test() { assert_eq!(42, 43); } will report: # my_first_test: ASSERTION FAILED at rust/kernel/lib.rs:251 Expected 42 == 43 to be true, but is false # my_first_test.speed: normal not ok 1 my_first_test - Support tests with checked 'Result' return types. The return value of test functions that return a 'Result' will be checked, thus one can now easily catch errors when e.g. using the '?' operator in tests. With this, a failing test like: #[test] fn my_test() -> Result { f()?; Ok(()) } will report: # my_test: ASSERTION FAILED at rust/kernel/lib.rs:321 Expected is_test_result_ok(my_test()) to be true, but is false # my_test.speed: normal not ok 1 my_test - Add 'kunit_tests' to the prelude. - Clarify the remaining language unstable features in use. - Compile 'core' with edition 2024 for Rust >= 1.87. - Workaround 'bindgen' issue with forward references to 'enum' types. - objtool: relax slice condition to cover more 'noreturn' functions. - Use absolute paths in macros referencing 'core' and 'kernel' crates. - Skip '-mno-fdpic' flag for bindgen in GCC 32-bit arm builds. - Clean some 'doc_markdown' lint hits -- we may enable it later on. 'kernel' crate: - 'alloc' module: - 'Box': support for type coercion, e.g. 'Box<T>' to 'Box<dyn U>' if 'T' implements 'U'. - 'Vec': implement new methods (prerequisites for nova-core and binder): 'truncate', 'resize', 'clear', 'pop', 'push_within_capacity' (with new error type 'PushError'), 'drain_all', 'retain', 'remove' (with new error type 'RemoveError'), insert_within_capacity' (with new error type 'InsertError'). In addition, simplify 'push' using 'spare_capacity_mut', split 'set_len' into 'inc_len' and 'dec_len', add type invariant 'len <= capacity' and simplify 'truncate' using 'dec_len'. - 'time' module: - Morph the Rust hrtimer subsystem into the Rust timekeeping subsystem, covering delay, sleep, timekeeping, timers. This new subsystem has all the relevant timekeeping C maintainers listed in the entry. - Replace 'Ktime' with 'Delta' and 'Instant' types to represent a duration of time and a point in time. - Temporarily add 'Ktime' to 'hrtimer' module to allow 'hrtimer' to delay converting to 'Instant' and 'Delta'. - 'xarray' module: - Add a Rust abstraction for the 'xarray' data structure. This abstraction allows Rust code to leverage the 'xarray' to store types that implement 'ForeignOwnable'. This support is a dependency for memory backing feature of the Rust null block driver, which is waiting to be merged. - Set up an entry in 'MAINTAINERS' for the XArray Rust support. Patches will go to the new Rust XArray tree and then via the Rust subsystem tree for now. - Allow 'ForeignOwnable' to carry information about the pointed-to type. This helps asserting alignment requirements for the pointer passed to the foreign language. - 'container_of!': retain pointer mut-ness and add a compile-time check of the type of the first parameter ('$field_ptr'). - Support optional message in 'static_assert!'. - Add C FFI types (e.g. 'c_int') to the prelude. - 'str' module: simplify KUnit tests 'format!' macro, convert 'rusttest' tests into KUnit, take advantage of the '-> Result' support in KUnit '#[test]'s. - 'list' module: add examples for 'List', fix path of 'assert_pinned!' (so far unused macro rule). - 'workqueue' module: remove 'HasWork::OFFSET'. - 'page' module: add 'inline' attribute. 'macros' crate: - 'module' macro: place 'cleanup_module()' in '.exit.text' section. 'pin-init' crate: - Add 'Wrapper<T>' trait for creating pin-initializers for wrapper structs with a structurally pinned value such as 'UnsafeCell<T>' or 'MaybeUninit<T>'. - Add 'MaybeZeroable' derive macro to try to derive 'Zeroable', but not error if not all fields implement it. This is needed to derive 'Zeroable' for all bindgen-generated structs. - Add 'unsafe fn cast_[pin_]init()' functions to unsafely change the initialized type of an initializer. These are utilized by the 'Wrapper<T>' implementations. - Add support for visibility in 'Zeroable' derive macro. - Add support for 'union's in 'Zeroable' derive macro. - Upstream dev news: streamline CI, fix some bugs. Add new workflows to check if the user-space version and the one in the kernel tree have diverged. Use the issues tab [1] to track them, which should help folks report and diagnose issues w.r.t. 'pin-init' better. [1] https://github.com/rust-for-linux/pin-init/issues Documentation: - Testing: add docs on the new KUnit '#[test]' tests. - Coding guidelines: explain that '///' vs. '//' applies to private items too. Add section on C FFI types. - Quick Start guide: update Ubuntu instructions and split them into "25.04" and "24.04 LTS and older". And a few other cleanups and improvements" * tag 'rust-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (78 commits) rust: list: Fix typo `much` in arc.rs rust: check type of `$ptr` in `container_of!` rust: workqueue: remove HasWork::OFFSET rust: retain pointer mut-ness in `container_of!` Documentation: rust: testing: add docs on the new KUnit `#[test]` tests Documentation: rust: rename `#[test]`s to "`rusttest` host tests" rust: str: take advantage of the `-> Result` support in KUnit `#[test]`'s rust: str: simplify KUnit tests `format!` macro rust: str: convert `rusttest` tests into KUnit rust: add `kunit_tests` to the prelude rust: kunit: support checked `-> Result`s in KUnit `#[test]`s rust: kunit: support KUnit-mapped `assert!` macros in `#[test]`s rust: make section names plural rust: list: fix path of `assert_pinned!` rust: compile libcore with edition 2024 for 1.87+ rust: dma: add missing Markdown code span rust: task: add missing Markdown code spans and intra-doc links rust: pci: fix docs related to missing Markdown code spans rust: alloc: add missing Markdown code span rust: alloc: add missing Markdown code spans ...
2025-05-26Merge tag 'x86-core-2025-05-25' of ↵Linus Torvalds1-2/+4
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull core x86 updates from Ingo Molnar: "Boot code changes: - A large series of changes to reorganize the x86 boot code into a better isolated and easier to maintain base of PIC early startup code in arch/x86/boot/startup/, by Ard Biesheuvel. Motivation & background: | Since commit | | c88d71508e36 ("x86/boot/64: Rewrite startup_64() in C") | | dated Jun 6 2017, we have been using C code on the boot path in a way | that is not supported by the toolchain, i.e., to execute non-PIC C | code from a mapping of memory that is different from the one provided | to the linker. It should have been obvious at the time that this was a | bad idea, given the need to sprinkle fixup_pointer() calls left and | right to manipulate global variables (including non-pointer variables) | without crashing. | | This C startup code has been expanding, and in particular, the SEV-SNP | startup code has been expanding over the past couple of years, and | grown many of these warts, where the C code needs to use special | annotations or helpers to access global objects. This tree includes the first phase of this work-in-progress x86 boot code reorganization. Scalability enhancements and micro-optimizations: - Improve code-patching scalability (Eric Dumazet) - Remove MFENCEs for X86_BUG_CLFLUSH_MONITOR (Andrew Cooper) CPU features enumeration updates: - Thorough reorganization and cleanup of CPUID parsing APIs (Ahmed S. Darwish) - Fix, refactor and clean up the cacheinfo code (Ahmed S. Darwish, Thomas Gleixner) - Update CPUID bitfields to x86-cpuid-db v2.3 (Ahmed S. Darwish) Memory management changes: - Allow temporary MMs when IRQs are on (Andy Lutomirski) - Opt-in to IRQs-off activate_mm() (Andy Lutomirski) - Simplify choose_new_asid() and generate better co