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2025-03-17objtool: Upgrade "Linked object detected" warning to errorJosh Poimboeuf
Force the user to fix their cmdline if they forget the '--link' option. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Brendan Jackman <jackmanb@google.com> Link: https://lore.kernel.org/r/8380bbf3a0fa86e03fd63f60568ae06a48146bc1.1741975349.git.jpoimboe@kernel.org
2025-03-17objtool: Consolidate option validationJosh Poimboeuf
The option validations are a bit scattered, consolidate them. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Brendan Jackman <jackmanb@google.com> Link: https://lore.kernel.org/r/8f886502fda1d15f39d7351b70d4ebe5903da627.1741975349.git.jpoimboe@kernel.org
2025-03-17objtool: Remove --unret dependency on --rethunkJosh Poimboeuf
With unret validation enabled and IBT/LTO disabled, objtool runs on TUs with --rethunk and on vmlinux.o with --unret. So this dependency isn't valid as they don't always run on the same object. This error never triggered before because --unret is always coupled with --noinstr, so the first conditional in opts_valid() returns early due to opts.noinstr being true. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/c6f5635784a28ed4b10ac4307b1858e015e6eff0.1741975349.git.jpoimboe@kernel.org
2025-03-17objtool: Increase per-function WARN_FUNC() rate limitJosh Poimboeuf
Increase the per-function WARN_FUNC() rate limit from 1 to 2. If the number of warnings for a given function goes beyond 2, print "skipping duplicate warning(s)". This helps root out additional warnings in a function that might be hiding behind the first one. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/aec318d66c037a51c9f376d6fb0e8ff32812a037.1741975349.git.jpoimboe@kernel.org
2025-03-17objtool: Update documentationJosh Poimboeuf
Fix some outdated information in the objtool doc. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/2552ee8b48631127bf269359647a7389edf5f002.1741975349.git.jpoimboe@kernel.org
2025-03-17objtool: Improve __noreturn annotation warningJosh Poimboeuf
Clarify what needs to be done to resolve the missing __noreturn warning. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/ab835a35d00bacf8aff0b56257df93f14fdd8224.1741975349.git.jpoimboe@kernel.org
2025-03-17objtool: Fix error handling inconsistencies in check()Josh Poimboeuf
Make sure all fatal errors are funneled through the 'out' label with a negative ret. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Brendan Jackman <jackmanb@google.com> Link: https://lore.kernel.org/r/0f49d6a27a080b4012e84e6df1e23097f44cc082.1741975349.git.jpoimboe@kernel.org
2025-03-17x86/traps: Make exc_double_fault() consistently noreturnJosh Poimboeuf
The CONFIG_X86_ESPFIX64 version of exc_double_fault() can return to its caller, but the !CONFIG_X86_ESPFIX64 version never does. In the latter case the compiler and/or objtool may consider it to be implicitly noreturn. However, due to the currently inflexible way objtool detects noreturns, a function's noreturn status needs to be consistent across configs. The current workaround for this issue is to suppress unreachable warnings for exc_double_fault()'s callers. Unfortunately that can result in ORC coverage gaps and potentially worse issues like inert static calls and silently disabled CPU mitigations. Instead, prevent exc_double_fault() from ever being implicitly marked noreturn by forcing a return behind a never-taken conditional. Until a more integrated noreturn detection method exists, this is likely the least objectionable workaround. Fixes: 55eeab2a8a11 ("objtool: Ignore exc_double_fault() __noreturn warnings") Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Brendan Jackman <jackmanb@google.com> Link: https://lore.kernel.org/r/d1f4026f8dc35d0de6cc61f2684e0cb6484009d1.1741975349.git.jpoimboe@kernel.org
2025-03-12objtool/LoongArch: Add support for goto tableTiezhu Yang
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 <yangtiezhu@loongson.cn> Link: https://lore.kernel.org/r/20250211115016.26913-6-yangtiezhu@loongson.cn Acked-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-03-12objtool/LoongArch: Add support for switch tableTiezhu Yang
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. The good news is that after continuous analysis and discussion, at last 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, the compiler changes make life much easier for switch table support of objtool on LoongArch. By now, there is an additional section ".discard.tablejump_annotate" to store the jump info as pairs of addresses, each pair contains the address of jump instruction and the address of jump table. In order to find switch table, it is easy to parse the relocation section ".rela.discard.tablejump_annotate" to get table_sec and table_offset, the rest process is somehow like x86. Additionally, it needs to get each table size. When compiling on LoongArch, there are unsorted table offsets of rodata if there exist many jump tables, it will get the wrong table end and find the wrong table jump destination instructions in add_jump_table(). Sort the rodata table offset by parsing ".rela.discard.tablejump_annotate" and then get each table size of rodata corresponded with each table jump instruction, it is used to check the table end and will break the process when parsing ".rela.rodata" to avoid getting the wrong jump destination instructions. Link: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=0ee028f55640 Link: https://github.com/llvm/llvm-project/commit/4c2c17756739 Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Link: https://lore.kernel.org/r/20250211115016.26913-5-yangtiezhu@loongson.cn Acked-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-03-12objtool: Handle PC relative relocation typeTiezhu Yang
For the most part, an absolute relocation type is used for rodata. In the case of STT_SECTION, reloc->sym->offset is always zero, for the other symbol types, reloc_addend(reloc) is always zero, thus it can use a simple statement "reloc->sym->offset + reloc_addend(reloc)" to obtain the symbol offset for various symbol types. When compiling on LoongArch, there exist PC relative relocation types for rodata, it needs to calculate the symbol offset with "S + A - PC" according to the spec of "ELF for the LoongArch Architecture". If there is only one jump table in the rodata, the "PC" is the entry address which is equal with the value of reloc_offset(reloc), at this time, reloc_offset(table) is 0. If there are many jump tables in the rodata, the "PC" is the offset of the jump table's base address which is equal with the value of reloc_offset(reloc) - reloc_offset(table). So for LoongArch, if the relocation type is PC relative, it can use a statement "reloc_offset(reloc) - reloc_offset(table)" to get the "PC" value when calculating the symbol offset with "S + A - PC" for one or many jump tables in the rodata. Add an arch-specific function arch_jump_table_sym_offset() to assign the symbol offset, for the most part that is an absolute relocation, the default value is "reloc->sym->offset + reloc_addend(reloc)" in the weak definition, it can be overridden by each architecture that has different requirements. Link: https://github.com/loongson/la-abi-specs/blob/release/laelf.adoc Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Link: https://lore.kernel.org/r/20250211115016.26913-4-yangtiezhu@loongson.cn Acked-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-03-12objtool: Handle different entry size of rodataTiezhu Yang
In the most cases, the entry size of rodata is 8 bytes because the relocation type is 64 bit. There are also 32 bit relocation types, the entry size of rodata should be 4 bytes in this case. Add an arch-specific function arch_reloc_size() to assign the entry size of rodata for x86, powerpc and LoongArch. Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Link: https://lore.kernel.org/r/20250211115016.26913-3-yangtiezhu@loongson.cn Acked-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-03-12objtool: Handle various symbol types of rodataTiezhu Yang
In the relocation section ".rela.rodata" of each .o file compiled with LoongArch toolchain, there are various symbol types such as STT_NOTYPE, STT_OBJECT, STT_FUNC in addition to the usual STT_SECTION, it needs to use reloc symbol offset instead of reloc addend to find the destination instruction in find_jump_table() and add_jump_table(). For the most part, an absolute relocation type is used for rodata. In the case of STT_SECTION, reloc->sym->offset is always zero, and for the other symbol types, reloc_addend(reloc) is always zero, thus it can use a simple statement "reloc->sym->offset + reloc_addend(reloc)" to obtain the symbol offset for various symbol types. Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Link: https://lore.kernel.org/r/20250211115016.26913-2-yangtiezhu@loongson.cn Acked-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-03-12objtool: Hide unnecessary compiler error messageDavid Engraf
The check for using old libelf prints an error message when libelf.h is not available but does not abort. This may confuse so hide the compiler error message. Signed-off-by: David Engraf <david.engraf@sysgo.com> Link: https://lore.kernel.org/r/20250203073610.206000-1-david.engraf@sysgo.com Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-03-04Merge branch 'x86/asm' into x86/core, to pick up dependent commitsIngo Molnar
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2025-03-04Merge branch 'x86/urgent' into x86/cpu, to pick up dependent commitsIngo Molnar
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2025-03-04x86/smp: Fix mwait_play_dead() and acpi_processor_ffh_play_dead() noreturn ↵Josh Poimboeuf
behavior Fix some related issues (done in a single patch to avoid introducing intermediate bisect warnings): 1) The SMP version of mwait_play_dead() doesn't return, but its !SMP counterpart does. Make its calling behavior consistent by resolving the !SMP version to a BUG(). It should never be called anyway, this just enforces that at runtime and enables its callers to be marked as __noreturn. 2) While the SMP definition of mwait_play_dead() is annotated as __noreturn, the declaration isn't. Nor is it listed in tools/objtool/noreturns.h. Fix that. 3) Similar to #1, the SMP version of acpi_processor_ffh_play_dead() doesn't return but its !SMP counterpart does. Make the !SMP version a BUG(). It should never be called. 4) acpi_processor_ffh_play_dead() doesn't return, but is lacking any __noreturn annotations. Fix that. This fixes the following objtool warnings: vmlinux.o: warning: objtool: acpi_processor_ffh_play_dead+0x67: mwait_play_dead() is missing a __noreturn annotation vmlinux.o: warning: objtool: acpi_idle_play_dead+0x3c: acpi_processor_ffh_play_dead() is missing a __noreturn annotation Fixes: a7dd183f0b38 ("x86/smp: Allow calling mwait_play_dead with an arbitrary hint") Fixes: 541ddf31e300 ("ACPI/processor_idle: Add FFH state handling") Reported-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Paul E. McKenney <paulmck@kernel.org> Link: https://lore.kernel.org/r/e885c6fa9e96a61471b33e48c2162d28b15b14c5.1740962711.git.jpoimboe@kernel.org
2025-03-03Merge tag 'v6.14-rc5' into x86/core, to pick up fixesIngo Molnar
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2025-02-28Merge tag 'objtool-urgent-2025-02-28' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull objtool fixes from Ingo Molnar: "Fix an objtool false positive, and objtool related build warnings that happens on PIE-enabled architectures such as LoongArch" * tag 'objtool-urgent-2025-02-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: objtool: Add bch2_trans_unlocked_or_in_restart_error() to bcachefs noreturns objtool: Fix C jump table annotations for Clang vmlinux.lds: Ensure that const vars with relocations are mapped R/O
2025-02-26objtool/powerpc: Add support for decoding all types of uncond branchesChristophe Leroy
Add support for 'bla' instruction. This is done by 'flagging' the address as an absolute address so that arch_jump_destination() can calculate it as expected. Because code is _always_ 4 bytes aligned, use bit 30 as flag. Also add support for 'b' and 'ba' instructions. Objtool call them jumps. And make sure the special 'bl .+4' used by clang in relocatable code is not seen as an 'unannotated intra-function call'. clang should use the special 'bcl 20,31,.+4' form like gcc but for the time being it does not so lets work around that. Link: https://github.com/llvm/llvm-project/issues/128644 Reviewed-by: Segher Boessenkool <segher@kewrnel.crashing.org> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com> Link: https://patch.msgid.link/bf0b4d554547bc34fa3d1af5b4e62a84c0bc182b.1740470510.git.christophe.leroy@csgroup.eu
2025-02-25Merge tag 'perf-tools-fixes-for-v6.14-2-2025-02-25' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools Pull perf tools fixes from Arnaldo Carvalho de Melo: - Fix tools/ quiet build Makefile infrastructure that was broken when working on tools/perf/ without testing on other tools/ living utilities. * tag 'perf-tools-fixes-for-v6.14-2-2025-02-25' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: tools: Remove redundant quiet setup tools: Unify top-level quiet infrastructure
2025-02-25objtool: Add bch2_trans_unlocked_or_in_restart_error() to bcachefs noreturnsYouling Tang
Fix the following objtool warning during build time: fs/bcachefs/btree_cache.o: warning: objtool: btree_node_lock.constprop.0() falls through to next function bch2_recalc_btree_reserve() fs/bcachefs/btree_update.o: warning: objtool: bch2_trans_update_get_key_cache() falls through to next function need_whiteout_for_snapshot() bch2_trans_unlocked_or_in_restart_error() is an Obviously Correct (tm) panic() wrapper, add it to the list of known noreturns. Fixes: b318882022a8 ("bcachefs: bch2_trans_verify_not_unlocked_or_in_restart()") Reported-by: k2ci <kernel-bot@kylinos.cn> Signed-off-by: Youling Tang <tangyouling@kylinos.cn> Reviewed-by: Kent Overstreet <kent.overstreet@linux.dev> Link: https://lore.kernel.org/r/20250218064230.219997-1-youling.tang@linux.dev Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-02-25objtool: Fix C jump table annotations for ClangArd Biesheuvel
A C jump table (such as the one used by the BPF interpreter) is a const global array of absolute code addresses, and this means that the actual values in the table may not be known until the kernel is booted (e.g., when using KASLR or when the kernel VA space is sized dynamically). When using PIE codegen, the compiler will default to placing such const global objects in .data.rel.ro (which is annotated as writable), rather than .rodata (which is annotated as read-only). As C jump tables are explicitly emitted into .rodata, this used to result in warnings for LoongArch builds (which uses PIE codegen for the entire kernel) like Warning: setting incorrect section attributes for .rodata..c_jump_table due to the fact that the explicitly specified .rodata section inherited the read-write annotation that the compiler uses for such objects when using PIE codegen. This warning was suppressed by explicitly adding the read-only annotation to the __attribute__((section(""))) string, by commit c5b1184decc8 ("compiler.h: specify correct attribute for .rodata..c_jump_table") Unfortunately, this hack does not work on Clang's integrated assembler, which happily interprets the appended section type and permission specifiers as part of the section name, which therefore no longer matches the hard-coded pattern '.rodata..c_jump_table' that objtool expects, causing it to emit a warning kernel/bpf/core.o: warning: objtool: ___bpf_prog_run+0x20: sibling call from callable instruction with modified stack frame Work around this, by emitting C jump tables into .data.rel.ro instead, which is treated as .rodata by the linker script for all builds, not just PIE based ones. Fixes: c5b1184decc8 ("compiler.h: specify correct attribute for .rodata..c_jump_table") Tested-by: Tiezhu Yang <yangtiezhu@loongson.cn> # on LoongArch Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20250221135704.431269-6-ardb+git@google.com Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-02-18tools: Remove redundant quiet setupCharlie Jenkins
Q is exported from Makefile.include so it is not necessary to manually set it. Reviewed-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Quentin Monnet <qmo@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Benjamin Tissoires <bentiss@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Eduard Zingerman <eddyz87@gmail.com> Cc: Hao Luo <haoluo@google.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Kosina <jikos@kernel.org> Cc: John Fastabend <john.fastabend@gmail.com> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: KP Singh <kpsingh@kernel.org> Cc: Lukasz Luba <lukasz.luba@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Martin KaFai Lau <martin.lau@linux.dev> Cc: Mykola Lysenko <mykolal@fb.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rafael@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Song Liu <song@kernel.org> Cc: Stanislav Fomichev <sdf@google.com> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Yonghong Song <yonghong.song@linux.dev> Cc: Zhang Rui <rui.zhang@intel.com> Link: https://lore.kernel.org/r/20250213-quiet_tools-v3-2-07de4482a581@rivosinc.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2025-02-18Merge tag 'v6.14-rc3' into x86/core, to pick up fixesIngo Molnar
Pick up upstream x86 fixes before applying new patches. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2025-02-16Merge tag 'objtool_urgent_for_v6.14_rc3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull objtool fixes from Borislav Petkov: - Move a warning about a lld.ld breakage into the verbose setting as said breakage has been fixed in the meantime - Teach objtool to ignore dangling jump table entries added by Clang * tag 'objtool_urgent_for_v6.14_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: objtool: Move dodgy linker warn to verbose objtool: Ignore dangling jump table entries
2025-02-14x86/alternative: Simplify callthunk patchingPeter Zijlstra
Now that paravirt call patching is implemented using alternatives, it is possible to avoid having to patch the alternative sites by including the altinstr_replacement calls in the call_sites list. This means we're now stacking relative adjustments like so: callthunks_patch_builtin_calls(): patches all function calls to target: func() -> func()-10 since the CALL accounting lives in the CALL_PADDING. This explicitly includes .altinstr_replacement alt_replace_call(): patches: x86_BUG() -> target() this patching is done in a relative manner, and will preserve the above adjustment, meaning that with calldepth patching it will do: x86_BUG()-10 -> target()-10 apply_relocation(): does code relocation, and adjusts all RIP-relative instructions to the new location, also in a relative manner. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Link: https://lore.kernel.org/r/20250207122546.617187089@infradead.org
2025-02-12objtool/rust: add one more `noreturn` Rust functionMiguel Ojeda
Starting with Rust 1.85.0 (currently in beta, to be released 2025-02-20), under some kernel configurations with `CONFIG_RUST_DEBUG_ASSERTIONS=y`, one may trigger a new `objtool` warning: rust/kernel.o: warning: objtool: _R...securityNtB2_11SecurityCtx8as_bytes() falls through to next function _R...core3ops4drop4Drop4drop() due to a call to the `noreturn` symbol: core::panicking::assert_failed::<usize, usize> Thus add it to the list so that `objtool` knows it is actually `noreturn`. Do so matching with `strstr` since it is a generic. See commit 56d680dd23c3 ("objtool/rust: list `noreturn` Rust functions") for more details. Cc: stable@vger.kernel.org # Needed in 6.12.y and 6.13.y only (Rust is pinned in older LTSs). Fixes: 56d680dd23c3 ("objtool/rust: list `noreturn` Rust functions") Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20250112143951.751139-1-ojeda@kernel.org [ Updated Cc: stable@ to include 6.13.y. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-02-08objtool: Move dodgy linker warn to verbosePeter Zijlstra
The lld.ld borkage is fixed in the latest llvm release (?) but will not be backported, meaning we're stuck with broken linker for a fair while. Lets not spam all clang build logs and move warning to verbose. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2025-02-08objtool: Ignore dangling jump table entriesJosh Poimboeuf
Clang sometimes leaves dangling unused jump table entries which point to the end of the function. Ignore them. Closes: https://lore.kernel.org/20250113235835.vqgvb7cdspksy5dn@jpoimboe Reported-by: Klaus Kusche <klaus.kusche@computerix.info> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/ee25c0b7e80113e950bd1d4c208b671d35774ff4.1736891751.git.jpoimboe@kernel.org
2025-01-21Merge tag 'objtool-core-2025-01-20' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull objtool updates from Ingo Molnar: - Introduce the generic section-based annotation infrastructure a.k.a. ASM_ANNOTATE/ANNOTATE (Peter Zijlstra) - Convert various facilities to ASM_ANNOTATE/ANNOTATE: (Peter Zijlstra) - ANNOTATE_NOENDBR - ANNOTATE_RETPOLINE_SAFE - instrumentation_{begin,end}() - VALIDATE_UNRET_BEGIN - ANNOTATE_IGNORE_ALTERNATIVE - ANNOTATE_INTRA_FUNCTION_CALL - {.UN}REACHABLE - Optimize the annotation-sections parsing code (Peter Zijlstra) - Centralize annotation definitions in <linux/objtool.h> - Unify & simplify the barrier_before_unreachable()/unreachable() definitions (Peter Zijlstra) - Convert unreachable() calls to BUG() in x86 code, as unreachable() has unreliable code generation (Peter Zijlstra) - Remove annotate_reachable() and annotate_unreachable(), as it's unreliable against compiler optimizations (Peter Zijlstra) - Fix non-standard ANNOTATE_REACHABLE annotation order (Peter Zijlstra) - Robustify the annotation code by warning about unknown annotation types (Peter Zijlstra) - Allow arch code to discover jump table size, in preparation of annotated jump table support (Ard Biesheuvel) * tag 'objtool-core-2025-01-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm: Convert unreachable() to BUG() objtool: Allow arch code to discover jump table size objtool: Warn about unknown annotation types objtool: Fix ANNOTATE_REACHABLE to be a normal annotation objtool: Convert {.UN}REACHABLE to ANNOTATE objtool: Remove annotate_{,un}reachable() loongarch: Use ASM_REACHABLE x86: Convert unreachable() to BUG() unreachable: Unify objtool: Collect more annotations in objtool.h objtool: Collapse annotate sequences objtool: Convert ANNOTATE_INTRA_FUNCTION_CALL to ANNOTATE objtool: Convert ANNOTATE_IGNORE_ALTERNATIVE to ANNOTATE objtool: Convert VALIDATE_UNRET_BEGIN to ANNOTATE objtool: Convert instrumentation_{begin,end}() to ANNOTATE objtool: Convert ANNOTATE_RETPOLINE_SAFE to ANNOTATE objtool: Convert ANNOTATE_NOENDBR to ANNOTATE objtool: Generic annotation infrastructure
2024-12-29Merge tag 'objtool-urgent-2024-12-29' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull objtool fix from Ingo Molnar: "Fix false positive objtool build warning related to a noreturn function in the bcachefs code" * tag 'objtool-urgent-2024-12-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: objtool: Add bch2_trans_unlocked_error() to bcachefs noreturns
2024-12-29objtool: Add bch2_trans_unlocked_error() to bcachefs noreturnschenchangcheng
Fix the following objtool warning during build time: fs/bcachefs/btree_trans_commit.o: warning: objtool: bch2_trans_commit_write_locked.isra.0() falls through to next function do_bch2_trans_commit.isra.0() fs/bcachefs/btree_trans_commit.o: warning: objtool: .text: unexpected end of section ...... fs/bcachefs/btree_update.o: warning: objtool: bch2_trans_update_get_key_cache() falls through to next function flush_new_cached_update() fs/bcachefs/btree_update.o: warning: objtool: flush_new_cached_update() falls through to next function bch2_trans_update_by_path() bch2_trans_unlocked_error() is an Obviously Correct (tm) panic() wrapper, add it to the list of known noreturns. [ mingo: Improved the changelog ] Fixes: fd104e2967b7 ("bcachefs: bch2_trans_verify_not_unlocked()") Signed-off-by: chenchangcheng <chenchangcheng@kylinos.cn> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20241220074847.3418134-1-ccc194101@163.com
2024-12-13objtool/x86: allow syscall instructionJuergen Gross
The syscall instruction is used in Xen PV mode for doing hypercalls. Allow syscall to be used in the kernel in case it is tagged with an unwind hint for objtool. This is part of XSA-466 / CVE-2024-53241. Reported-by: Andrew Cooper <andrew.cooper3@citrix.com> Signed-off-by: Juergen Gross <jgross@suse.com> Co-developed-by: Peter Zijlstra <peterz@infradead.org>
2024-12-02objtool: Allow arch code to discover jump table sizeArd Biesheuvel
In preparation for adding support for annotated jump tables, where ELF relocations and symbols are used to describe the locations of jump tables in the executable, refactor the jump table discovery logic so the table size can be returned from arch_find_switch_table(). Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20241011170847.334429-12-ardb+git@google.com
2024-12-02objtool: Warn about unknown annotation typesPeter Zijlstra
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/20241128094312.611961175@infradead.org
2024-12-02objtool: Fix ANNOTATE_REACHABLE to be a normal annotationPeter Zijlstra
Currently REACHABLE is weird for being on the instruction after the instruction it modifies. Since all REACHABLE annotations have an explicit instruction, flip them around. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/20241128094312.494176035@infradead.org
2024-12-02objtool: Convert {.UN}REACHABLE to ANNOTATEPeter Zijlstra
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/20241128094312.353431347@infradead.org
2024-12-02objtool: Remove annotate_{,un}reachable()Peter Zijlstra
There are no users of annotate_reachable() left. And the annotate_unreachable() usage in unreachable() is plain wrong; it will hide dangerous fall-through code-gen. Remove both. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/20241128094312.235637588@infradead.org
2024-12-02objtool: Collapse annotate sequencesPeter Zijlstra
Reduce read_annotate() runs by collapsing subsequent runs into a single call. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/20241128094311.688871544@infradead.org
2024-12-02objtool: Convert ANNOTATE_INTRA_FUNCTION_CALL to ANNOTATEPeter Zijlstra
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/20241128094311.584892071@infradead.org
2024-12-02objtool: Convert ANNOTATE_IGNORE_ALTERNATIVE to ANNOTATEPeter Zijlstra
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/20241128094311.465691316@infradead.org
2024-12-02objtool: Convert VALIDATE_UNRET_BEGIN to ANNOTATEPeter Zijlstra
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/20241128094311.358508242@infradead.org
2024-12-02objtool: Convert instrumentation_{begin,end}() to ANNOTATEPeter Zijlstra
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/20241128094311.245980207@infradead.org
2024-12-02objtool: Convert ANNOTATE_RETPOLINE_SAFE to ANNOTATEPeter Zijlstra
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/20241128094311.145275669@infradead.org
2024-12-02objtool: Convert ANNOTATE_NOENDBR to ANNOTATEPeter Zijlstra
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/20241128094311.042140333@infradead.org
2024-12-02objtool: Generic annotation infrastructurePeter Zijlstra
Avoid endless .discard.foo sections for each annotation, create a single .discard.annotate_insn section that takes an annotation type along with the instruction. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/20241128094310.932794537@infradead.org
2024-11-30Merge tag 'kbuild-v6.13' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Add generic support for built-in boot DTB files - Enable TAB cycling for dialog buttons in nconfig - Fix issues in streamline_config.pl - Refactor Kconfig - Add support for Clang's AutoFDO (Automatic Feedback-Directed Optimization) - Add support for Clang's Propeller, a profile-guided optimization. - Change the working directory to the external module directory for M= builds - Support building external modules in a separate output directory - Enable objtool for *.mod.o and additional kernel objects - Use lz4 instead of deprecated lz4c - Work around a performance issue with "git describe" - Refactor modpost * tag 'kbuild-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (85 commits) kbuild: rename .tmp_vmlinux.kallsyms0.syms to .tmp_vmlinux0.syms gitignore: Don't ignore 'tags' directory kbuild: add dependency from vmlinux to resolve_btfids modpost: replace tdb_hash() with hash_str() kbuild: deb-pkg: add python3:native to build dependency genksyms: reduce indentation in export_symbol() modpost: improve error messages in device_id_check() modpost: rename alias symbol for MODULE_DEVICE_TABLE() modpost: rename variables in handle_moddevtable() modpost: move strstarts() to modpost.h modpost: convert do_usb_table() to a generic handler modpost: convert do_of_table() to a generic handler modpost: convert do_pnp_device_entry() to a generic handler modpost: convert do_pnp_card_entries() to a generic handler modpost: call module_alias_printf() from all do_*_entry() functions modpost: pass (struct module *) to do_*_entry() functions modpost: remove DEF_FIELD_ADDR_VAR() macro modpost: deduplicate MODULE_ALIAS() for all drivers modpost: introduce module_alias_printf() helper modpost: remove unnecessary check in do_acpi_entry() ...
2024-11-27kbuild: Add Propeller configuration for kernel buildRong Xu
Add the build support for using Clang's Propeller optimizer. Like AutoFDO, Propeller uses hardware sampling to gather information about the frequency of execution of different code paths within a binary. This information is then used to guide the compiler's optimization decisions, resulting in a more efficient binary. The support requires a Clang compiler LLVM 19 or later, and the create_llvm_prof tool (https://github.com/google/autofdo/releases/tag/v0.30.1). This commit is limited to x86 platforms that support PMU features like LBR on Intel machines and AMD Zen3 BRS. Here is an example workflow for building an AutoFDO+Propeller optimized kernel: 1) Build the kernel on the host machine, with AutoFDO and Propeller build config CONFIG_AUTOFDO_CLANG=y CONFIG_PROPELLER_CLANG=y then $ make LLVM=1 CLANG_AUTOFDO_PROFILE=<autofdo_profile> “<autofdo_profile>” is the profile collected when doing a non-Propeller AutoFDO build. This step builds a kernel that has the same optimization level as AutoFDO, plus a metadata section that records basic block information. This kernel image runs as fast as an AutoFDO optimized kernel. 2) Install the kernel on test/production machines. 3) Run the load tests. The '-c' option in perf specifies the sample event period. We suggest using a suitable prime number, like 500009, for this purpose. For Intel platforms: $ perf record -e BR_INST_RETIRED.NEAR_TAKEN:k -a -N -b -c <count> \ -o <perf_file> -- <loadtest> For AMD platforms: The supported system are: Zen3 with BRS, or Zen4 with amd_lbr_v2 # To see if Zen3 support LBR: $ cat proc/cpuinfo | grep " brs" # To see if Zen4 support LBR: $ cat proc/cpuinfo | grep amd_lbr_v2 # If the result is yes, then collect the profile using: $ perf record --pfm-events RETIRED_TAKEN_BRANCH_INSTRUCTIONS:k -a \ -N -b -c <count> -o <perf_file> -- <loadtest> 4) (Optional) Download the raw perf file to the host machine. 5) Generate Propeller profile: $ create_llvm_prof --binary=<vmlinux> --profile=<perf_file> \ --format=propeller --propeller_output_module_name \ --out=<propeller_profile_prefix>_cc_profile.txt \ --propeller_symorder=<propeller_profile_prefix>_ld_profile.txt “create_llvm_prof” is the profile conversion tool, and a prebuilt binary for linux can be found on https://github.com/google/autofdo/releases/tag/v0.30.1 (can also build from source). "<propeller_profile_prefix>" can be something like "/home/user/dir/any_string". This command generates a pair of Propeller profiles: "<propeller_profile_prefix>_cc_profile.txt" and "<propeller_profile_prefix>_ld_profile.txt". 6) Rebuild the kernel using the AutoFDO and Propeller profile files. CONFIG_AUTOFDO_CLANG=y CONFIG_PROPELLER_CLANG=y and $ make LLVM=1 CLANG_AUTOFDO_PROFILE=<autofdo_profile> \ CLANG_PROPELLER_PROFILE_PREFIX=<propeller_profile_prefix> Co-developed-by: Han Shen <shenhan@google.com> Signed-off-by: Han Shen <shenhan@google.com> Signed-off-by: Rong Xu <xur@google.com> Suggested-by: Sriraman Tallam <tmsriram@google.com> Suggested-by: Krzysztof Pszeniczny <kpszeniczny@google.com> Suggested-by: Nick Desaulniers <ndesaulniers@google.com> Suggested-by: Stephane Eranian <eranian@google.com> Tested-by: Yonghong Song <yonghong.song@linux.dev> Tested-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Kees Cook <kees@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-11-21Merge tag 'reiserfs_delete' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs Pull reiserfs removal from Jan Kara: "The deprecation period of reiserfs is ending at the end of this year so it is time to remove it" * tag 'reiserfs_delete' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: reiserfs: The last commit
generated by cgit (git 2.34.1) at 2025-07-14 23:40:49 +0000