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7 daysobjtool/rust: add one more `noreturn` Rust function for Rust 1.89.0Miguel Ojeda
commit aa7b65c2a29e8b07057b13624102c6810597c0d5 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-06-19objtool/rust: relax slice condition to cover more `noreturn` Rust functionsMiguel Ojeda
commit cbeaa41dfe26b72639141e87183cb23e00d4b0dd upstream. Developers are indeed hitting other of the `noreturn` slice symbols in Nova [1], thus relax the last check in the list so that we catch all of them, i.e. *_4core5slice5index22slice_index_order_fail *_4core5slice5index24slice_end_index_len_fail *_4core5slice5index26slice_start_index_len_fail *_4core5slice5index29slice_end_index_overflow_fail *_4core5slice5index31slice_start_index_overflow_fail These all exist since at least Rust 1.78.0, thus backport it too. See commit 56d680dd23c3 ("objtool/rust: list `noreturn` Rust functions") for more details. Cc: stable@vger.kernel.org # Needed in 6.12.y and later. Cc: John Hubbard <jhubbard@nvidia.com> Cc: Timur Tabi <ttabi@nvidia.com> Cc: Kane York <kanepyork@gmail.com> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Reported-by: Joel Fernandes <joelagnelf@nvidia.com> Fixes: 56d680dd23c3 ("objtool/rust: list `noreturn` Rust functions") Closes: https://lore.kernel.org/rust-for-linux/20250513180757.GA1295002@joelnvbox/ [1] Tested-by: Joel Fernandes <joelagnelf@nvidia.com> Link: https://lore.kernel.org/r/20250520185555.825242-1-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-05-29objtool: Fix error handling inconsistencies in check()Josh Poimboeuf
[ Upstream commit b745962cb97569aad026806bb0740663cf813147 ] 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 Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-29objtool: Properly disable uaccess validationJosh Poimboeuf
[ Upstream commit e1a9dda74dbffbc3fa2069ff418a1876dc99fb14 ] If opts.uaccess isn't set, the uaccess validation is disabled, but only partially: it doesn't read the uaccess_safe_builtin list but still tries to do the validation. Disable it completely to prevent false warnings. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/0e95581c1d2107fb5f59418edf2b26bba38b0cbb.1742852846.git.jpoimboe@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-18objtool/rust: add one more `noreturn` Rust function for Rust 1.87.0Miguel Ojeda
commit 19f5ca461d5fc09bdf93a9f8e4bd78ed3a49dc71 upstream. Starting with Rust 1.87.0 (expected 2025-05-15), `objtool` may report: rust/core.o: warning: objtool: _R..._4core9panicking9panic_fmt() falls through to next function _R..._4core9panicking18panic_nounwind_fmt() rust/core.o: warning: objtool: _R..._4core9panicking18panic_nounwind_fmt() falls through to next function _R..._4core9panicking5panic() The reason is that `rust_begin_unwind` is now mangled: _R..._7___rustc17rust_begin_unwind 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. Alternatively, we could remove the fixed one in `noreturn.h` and relax this test to cover both, but it seems best to be strict as long as we can. 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> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20250502140237.1659624-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-05-02objtool: Ignore end-of-section jumps for KCOV/GCOVJosh Poimboeuf
commit 0d7597749f5a3ac67851d3836635d084df15fb66 upstream. When KCOV or GCOV is enabled, dead code can be left behind, in which case objtool silences unreachable and undefined behavior (fallthrough) warnings. Fallthrough warnings, and their variant "end of section" warnings, were silenced with the following commit: 6b023c784204 ("objtool: Silence more KCOV warnings") Another variant of a fallthrough warning is a jump to the end of a function. If that function happens to be at the end of a section, the jump destination doesn't actually exist. Normally that would be a fatal objtool error, but for KCOV/GCOV it's just another undefined behavior fallthrough. Silence it like the others. Fixes the following warning: drivers/iommu/dma-iommu.o: warning: objtool: iommu_dma_sw_msi+0x92: can't find jump dest instruction at .text+0x54d5 Fixes: 6b023c784204 ("objtool: Silence more KCOV warnings") Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/08fbe7d7e1e20612206f1df253077b94f178d93e.1743481539.git.jpoimboe@kernel.org Closes: https://lore.kernel.org/314f8809-cd59-479b-97d7-49356bf1c8d1@infradead.org/ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-05-02objtool: Stop UNRET validation on UD2Josh Poimboeuf
[ Upstream commit 9f9cc012c2cbac4833746a0182e06a8eec940d19 ] In preparation for simplifying INSN_SYSCALL, make validate_unret() terminate control flow on UD2 just like validate_branch() already does. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/ce841269e7e28c8b7f32064464a9821034d724ff.1744095216.git.jpoimboe@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-02objtool, panic: Disable SMAP in __stack_chk_fail()Josh Poimboeuf
[ Upstream commit 72c774aa9d1e16bfd247096935e7dae194d84929 ] __stack_chk_fail() can be called from uaccess-enabled code. Make sure uaccess gets disabled before calling panic(). Fixes the following warning: kernel/trace/trace_branch.o: error: objtool: ftrace_likely_update+0x1ea: call to __stack_chk_fail() with UACCESS enabled Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/a3e97e0119e1b04c725a8aa05f7bc83d98e657eb.1742852847.git.jpoimboe@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-02objtool: Silence more KCOV warningsJosh Poimboeuf
[ Upstream commit 6b023c7842048c4bbeede802f3cf36b96c7a8b25 ] In the past there were issues with KCOV triggering unreachable instruction warnings, which is why unreachable warnings are now disabled with CONFIG_KCOV. Now some new KCOV warnings are showing up with GCC 14: vmlinux.o: warning: objtool: cpuset_write_resmask() falls through to next function cpuset_update_active_cpus.cold() drivers/usb/core/driver.o: error: objtool: usb_deregister() falls through to next function usb_match_device() sound/soc/codecs/snd-soc-wcd934x.o: warning: objtool: .text.wcd934x_slim_irq_handler: unexpected end of section All are caused by GCC KCOV not finishing an optimization, leaving behind a never-taken conditional branch to a basic block which falls through to the next function (or end of section). At a high level this is similar to the unreachable warnings mentioned above, in that KCOV isn't fully removing dead code. Treat it the same way by adding these to the list of warnings to ignore with CONFIG_KCOV. Reported-by: Ingo Molnar <mingo@kernel.org> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/66a61a0b65d74e072d3dc02384e395edb2adc3c5.1742852846.git.jpoimboe@kernel.org Closes: https://lore.kernel.org/Z9iTsI09AEBlxlHC@gmail.com Closes: https://lore.kernel.org/oe-kbuild-all/202503180044.oH9gyPeg-lkp@intel.com/ Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-25objtool/rust: add one more `noreturn` Rust function for Rust 1.86.0Miguel Ojeda
commit a3cd5f507b72c0532c3345b6913557efab34f405 upstream. Starting with Rust 1.86.0 (see upstream commit b151b513ba2b ("Insert null checks for pointer dereferences when debug assertions are enabled") [1]), under some kernel configurations with `CONFIG_RUST_DEBUG_ASSERTIONS=y`, one may trigger a new `objtool` warning: rust/kernel.o: warning: objtool: _R..._6kernel9workqueue6system() falls through to next function _R...9workqueue14system_highpri() due to a call to the `noreturn` symbol: core::panicking::panic_null_pointer_dereference Thus add it 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). Fixes: 56d680dd23c3 ("objtool/rust: list `noreturn` Rust functions") Link: https://github.com/rust-lang/rust/commit/b151b513ba2b65c7506ec1a80f2712bbd09154d1 [1] Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20250413002338.1741593-1-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-04-20objtool: Fix INSN_CONTEXT_SWITCH handling in validate_unret()Josh Poimboeuf
[ Upstream commit a8df7d0ef92eca28c610206c6748daf537ac0586 ] The !CONFIG_IA32_EMULATION version of xen_entry_SYSCALL_compat() ends with a SYSCALL instruction which is classified by objtool as INSN_CONTEXT_SWITCH. Unlike validate_branch(), validate_unret() doesn't consider INSN_CONTEXT_SWITCH in a non-function to be a dead end, so it keeps going past the end of xen_entry_SYSCALL_compat(), resulting in the following warning: vmlinux.o: warning: objtool: xen_reschedule_interrupt+0x2a: RET before UNTRAIN Fix that by adding INSN_CONTEXT_SWITCH handling to validate_unret() to match what validate_branch() is already doing. Fixes: a09a6e2399ba ("objtool: Add entry UNRET validation") Reported-by: Andrew Cooper <andrew.cooper3@citrix.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/f5eda46fd09f15b1f5cde3d9ae3b92b958342add.1744095216.git.jpoimboe@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10objtool: Fix verbose disassembly if CROSS_COMPILE isn't setDavid Laight
[ Upstream commit e77956e4e5c11218e60a1fe8cdbccd02476f2e56 ] In verbose mode, when printing the disassembly of affected functions, if CROSS_COMPILE isn't set, the objdump command string gets prefixed with "(null)". Somehow this worked before. Maybe some versions of glibc return an empty string instead of NULL. Fix it regardless. [ jpoimboe: Rewrite commit log. ] Fixes: ca653464dd097 ("objtool: Add verbose option for disassembling affected functions") Signed-off-by: David Laight <david.laight.linux@gmail.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250215142321.14081-1-david.laight.linux@gmail.com Link: https://lore.kernel.org/r/b931a4786bc0127aa4c94e8b35ed617dcbd3d3da.1743481539.git.jpoimboe@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10objtool: Fix segfault in ignore_unreachable_insn()Josh Poimboeuf
[ Upstream commit 69d41d6dafff0967565b971d950bd10443e4076c ] Check 'prev_insn' before dereferencing it. Fixes: bd841d6154f5 ("objtool: Fix CONFIG_UBSAN_TRAP unreachable warnings") Reported-by: Arnd Bergmann <arnd@arndb.de> Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/5df4ff89c9e4b9e788b77b0531234ffa7ba03e9e.1743136205.git.jpoimboe@kernel.org Closes: https://lore.kernel.org/d86b4cc6-0b97-4095-8793-a7384410b8ab@app.fastmail.com Closes: https://lore.kernel.org/Z-V_rruKY0-36pqA@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10x86/traps: Make exc_double_fault() consistently noreturnJosh Poimboeuf
[ Upstream commit 8085fcd78c1a3dbdf2278732579009d41ce0bc4e ] 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 Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-22objtool: Ignore dangling jump table entriesJosh Poimboeuf
[ Upstream commit 3724062ca2b1364f02cf44dbea1a552227844ad1 ] 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 Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-07objtool: Fix C jump table annotations for ClangArd Biesheuvel
[ Upstream commit 73cfc53cc3b6380eccf013049574485f64cb83ca ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-07objtool: Remove annotate_{,un}reachable()Peter Zijlstra
[ Upstream commit 06e24745985c8dd0da18337503afcf2f2fdbdff1 ] 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 Stable-dep-of: 73cfc53cc3b6 ("objtool: Fix C jump table annotations for Clang") Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-21objtool/rust: add one more `noreturn` Rust functionMiguel Ojeda
commit cee6f9a9c87b6ecfb51845950c28216b231c3610 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-19objtool/x86: allow syscall instructionJuergen Gross
commit dda014ba59331dee4f3b773a020e109932f4bd24 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-27Merge tag 'loongarch-6.12' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson Pull LoongArch updates from Huacai Chen: - Fix objtool about do_syscall() and Clang - Enable generic CPU vulnerabilites support - Enable ACPI BGRT handling - Rework CPU feature probe from CPUCFG/IOCSR - Add ARCH_HAS_SET_MEMORY support - Add ARCH_HAS_SET_DIRECT_MAP support - Improve hardware page table walker - Simplify _percpu_read() and _percpu_write() - Add advanced extended IRQ model documentions - Some bug fixes and other small changes * tag 'loongarch-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson: Docs/LoongArch: Add advanced extended IRQ model description LoongArch: Remove posix_types.h include from sigcontext.h LoongArch: Fix memleak in pci_acpi_scan_root() LoongArch: Simplify _percpu_read() and _percpu_write() LoongArch: Improve hardware page table walker LoongArch: Add ARCH_HAS_SET_DIRECT_MAP support LoongArch: Add ARCH_HAS_SET_MEMORY support LoongArch: Rework CPU feature probe from CPUCFG/IOCSR LoongArch: Enable ACPI BGRT handling LoongArch: Enable generic CPU vulnerabilites support LoongArch: Remove STACK_FRAME_NON_STANDARD(do_syscall) LoongArch: Set AS_HAS_THIN_ADD_SUB as y if AS_IS_LLVM LoongArch: Enable objtool for Clang objtool: Handle frame pointer related instructions
2024-09-17objtool: Handle frame pointer related instructionsTiezhu Yang
After commit a0f7085f6a63 ("LoongArch: Add RANDOMIZE_KSTACK_OFFSET support"), there are three new instructions "addi.d $fp, $sp, 32", "sub.d $sp, $sp, $t0" and "addi.d $sp, $fp, -32" for the secondary stack in do_syscall(), then there is a objtool warning "return with modified stack frame" and no handle_syscall() which is the previous frame of do_syscall() in the call trace when executing the command "echo l > /proc/sysrq-trigger". objdump shows something like this: 0000000000000000 <do_syscall>: 0: 02ff8063 addi.d $sp, $sp, -32 4: 29c04076 st.d $fp, $sp, 16 8: 29c02077 st.d $s0, $sp, 8 c: 29c06061 st.d $ra, $sp, 24 10: 02c08076 addi.d $fp, $sp, 32 ... 74: 0011b063 sub.d $sp, $sp, $t0 ... a8: 4c000181 jirl $ra, $t0, 0 ... dc: 02ff82c3 addi.d $sp, $fp, -32 e0: 28c06061 ld.d $ra, $sp, 24 e4: 28c04076 ld.d $fp, $sp, 16 e8: 28c02077 ld.d $s0, $sp, 8 ec: 02c08063 addi.d $sp, $sp, 32 f0: 4c000020 jirl $zero, $ra, 0 The instruction "sub.d $sp, $sp, $t0" changes the stack bottom and the new stack size is a random value, in order to find the return address of do_syscall() which is stored in the original stack frame after executing "jirl $ra, $t0, 0", it should use fp which points to the original stack top. At the beginning, the thought is tended to decode the secondary stack instruction "sub.d $sp, $sp, $t0" and set it as a label, then check this label for the two frame pointer instructions to change the cfa base and cfa offset during the period of secondary stack in update_cfi_state(). This is valid for GCC but invalid for Clang due to there are different secondary stack instructions for ClangBuiltLinux on LoongArch, something like this: 0000000000000000 <do_syscall>: ... 88: 00119064 sub.d $a0, $sp, $a0 8c: 00150083 or $sp, $a0, $zero ... Actually, it equals to a single instruction "sub.d $sp, $sp, $a0", but there is no proper condition to check it as a label like GCC, and so the beginning thought is not a good way. Essentially, there are two special frame pointer instructions which are "addi.d $fp, $sp, imm" and "addi.d $sp, $fp, imm", the first one points fp to the original stack top and the second one restores the original stack bottom from fp. Based on the above analysis, in order to avoid adding an arch-specific update_cfi_state(), we just add a member "frame_pointer" in the "struct symbol" as a label to avoid affecting the current normal case, then set it as true only if there is "addi.d $sp, $fp, imm". The last is to check this label for the two frame pointer instructions to change the cfa base and cfa offset in update_cfi_state(). Tested with the following two configs: (1) CONFIG_RANDOMIZE_KSTACK_OFFSET=y && CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT=n (2) CONFIG_RANDOMIZE_KSTACK_OFFSET=y && CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT=y By the way, there is no effect for x86 with this patch, tested on the x86 machine with Fedora 40 system. Cc: stable@vger.kernel.org # 6.9+ Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-08-18objtool/rust: list `noreturn` Rust functionsMiguel Ojeda
Rust functions may be `noreturn` (i.e. diverging) by returning the "never" type, `!`, e.g. fn f() -> ! { loop {} } Thus list the known `noreturn` functions to avoid such warnings. Without this, `objtool` would complain if enabled for Rust, e.g.: rust/core.o: warning: objtool: _R...9panic_fmt() falls through to next function _R...18panic_nounwind_fmt() rust/alloc.o: warning: objtool: .text: unexpected end of section In order to do so, we cannot match symbols' names exactly, for two reasons: - Rust mangling scheme [1] contains disambiguators [2] which we cannot predict (e.g. they may vary depending on the compiler version). One possibility to solve this would be to parse v0 and ignore/zero those before comparison. - Some of the diverging functions come from `core`, i.e. the Rust standard library, which may change with each compiler version since they are implementation details (e.g. `panic_internals`). Thus, to workaround both issues, only part of the symbols are matched, instead of using the `NORETURN` macro in `noreturns.h`. Ideally, just like for the C side, we should have a better solution. For instance, the compiler could give us the list via something like: $ rustc --emit=noreturns ... [ Kees agrees this should be automated and Peter says: So it would be fairly simple to make objtool consume a magic section emitted by the compiler.. I think we've asked the compiler folks for that at some point even, but I don't have clear recollections. We will ask upstream Rust about it. And if they agree, then perhaps we can get Clang/GCC to implement something similar too -- for this sort of thing we can take advantage of the shorter cycles of `rustc` as well as their unstable features concept to experiment. Gary proposed using DWARF (though it would need to be available), and wrote a proof of concept script using the `object` and `gimli` crates: https://gist.github.com/nbdd0121/449692570622c2f46a29ad9f47c3379a - Miguel ] Link: https://rust-lang.github.io/rfcs/2603-rust-symbol-name-mangling-v0.html [1] Link: https://doc.rust-lang.org/rustc/symbol-mangling/v0.html#disambiguator [2] Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Kees Cook <kees@kernel.org> Tested-by: Benno Lossin <benno.lossin@proton.me> Link: https://lore.kernel.org/r/20240725183325.122827-6-ojeda@kernel.org [ Added `len_mismatch_fail` symbol for new `kernel` crate code merged since then as well as 3 more `core::panicking` symbols that appear in `RUST_DEBUG_ASSERTIONS=y` builds. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-07-03kmsan: allow disabling KMSAN checks for the current taskIlya Leoshkevich
Like for KASAN, it's useful to temporarily disable KMSAN checks around, e.g., redzone accesses. Introduce kmsan_disable_current() and kmsan_enable_current(), which are similar to their KASAN counterparts. Make them reentrant in order to handle memory allocations in interrupt context. Repurpose the allow_reporting field for this. Link: https://lkml.kernel.org/r/20240621113706.315500-12-iii@linux.ibm.com Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Reviewed-by: Alexander Potapenko <glider@google.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: <kasan-dev@googlegroups.com> Cc: Marco Elver <elver@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-03-30objtool: Fix compile failure when using the x32 compilerMikulas Patocka
When compiling the v6.9-rc1 kernel with the x32 compiler, the following errors are reported. The reason is that we take an "unsigned long" variable and print it using "PRIx64" format string. In file included from check.c:16: check.c: In function ‘add_dead_ends’: /usr/src/git/linux-2.6/tools/objtool/include/objtool/warn.h:46:17: error: format ‘%llx’ expects argument of type ‘long long unsigned int’, but argument 5 has type ‘long unsigned int’ [-Werror=format=] 46 | "%s: warning: objtool: " format "\n", \ | ^~~~~~~~~~~~~~~~~~~~~~~~ check.c:613:33: note: in expansion of macro ‘WARN’ 613 | WARN("can't find unreachable insn at %s+0x%" PRIx64, | ^~~~ ... Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: linux-kernel@vger.kernel.org
2024-03-22Merge tag 'loongarch-6.9' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson Pull LoongArch updates from Huacai Chen: - Add objtool support for LoongArch - Add ORC stack unwinder support for LoongArch - Add kernel livepatching support for LoongArch - Select ARCH_HAS_CURRENT_STACK_POINTER in Kconfig - Select HAVE_ARCH_USERFAULTFD_MINOR in Kconfig - Some bug fixes and other small changes * tag 'loongarch-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson: LoongArch/crypto: Clean up useless assignment operations LoongArch: Define the __io_aw() hook as mmiowb() LoongArch: Remove superfluous flush_dcache_page() definition LoongArch: Move {dmw,tlb}_virt_to_page() definition to page.h LoongArch: Change __my_cpu_offset definition to avoid mis-optimization LoongArch: Select HAVE_ARCH_USERFAULTFD_MINOR in Kconfig LoongArch: Select ARCH_HAS_CURRENT_STACK_POINTER in Kconfig LoongArch: Add kernel livepatching support LoongArch: Add ORC stack unwinder support objtool: Check local label in read_unwind_hints() objtool: Check local label in add_dead_ends() objtool/LoongArch: Enable orc to be built objtool/x86: Separate arch-specific and generic parts objtool/LoongArch: Implement instruction decoder objtool/LoongArch: Enable objtool to be built
2024-03-12Merge tag 'hardening-v6.9-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull hardening updates from Kees Cook: "As is pretty normal for this tree, there are changes all over the place, especially for small fixes, selftest improvements, and improved macro usability. Some header changes ended up landing via this tree as they depended on the string header cleanups. Also, a notable set of changes is the work for the reintroduction of the UBSAN signed integer overflow sanitizer so that we can continue to make improvements on the compiler side to make this sanitizer a more viable future security hardening option. Summary: - string.h and related header cleanups (Tanzir Hasan, Andy Shevchenko) - VMCI memcpy() usage and struct_size() cleanups (Vasiliy Kovalev, Harshit Mogalapalli) - selftests/powerpc: Fix load_unaligned_zeropad build failure (Michael Ellerman) - hardened Kconfig fragment updates (Marco Elver, Lukas Bulwahn) - Handle tail call optimization better in LKDTM (Douglas Anderson) - Use long form types in overflow.h (Andy Shevchenko) - Add flags param to string_get_size() (Andy Shevchenko) - Add Coccinelle script for potential struct_size() use (Jacob Keller) - Fix objtool corner case under KCFI (Josh Poimboeuf) - Drop 13 year old backward compat CAP_SYS_ADMIN check (Jingzi Meng) - Add str_plural() helper (Michal Wajdeczko, Kees Cook) - Ignore relocations in .notes section - Add comments to explain how __is_constexpr() works - Fix m68k stack alignment expectations in stackinit Kunit test - Convert string selftests to KUnit - Add KUnit tests for fortified string functions - Improve reporting during fortified string warnings - Allow non-type arg to type_max() and type_min() - Allow strscpy() to be called with only 2 arguments - Add binary mode to leaking_addresses scanner - Various small cleanups to leaking_addresses scanner - Adding wrapping_*() arithmetic helper - Annotate initial signed integer wrap-around in refcount_t - Add explicit UBSAN section to MAINTAINERS - Fix UBSAN self-test warnings - Simplify UBSAN build via removal of CONFIG_UBSAN_SANITIZE_ALL - Reintroduce UBSAN's signed overflow sanitizer" * tag 'hardening-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (51 commits) selftests/powerpc: Fix load_unaligned_zeropad build failure string: Convert helpers selftest to KUnit string: Convert selftest to KUnit sh: Fix build with CONFIG_UBSAN=y compiler.h: Explain how __is_constexpr() works overflow: Allow non-type arg to type_max() and type_min() VMCI: Fix possible memcpy() run-time warning in vmci_datagram_invoke_guest_handler() lib/string_helpers: Add flags param to string_get_size() x86, relocs: Ignore relocations in .notes section objtool: Fix UNWIND_HINT_{SAVE,RESTORE} across basic blocks overflow: Use POD in check_shl_overflow() lib: stackinit: Adjust target string to 8 bytes for m68k sparc: vdso: Disable UBSAN instrumentation kernel.h: Move lib/cmdline.c prototypes to string.h leaking_addresses: Provide mechanism to scan binary files leaking_addresses: Ignore input device status lines leaking_addresses: Use File::Temp for /tmp files MAINTAINERS: Update LEAKING_ADDRESSES details fortify: Improve buffer overflow reporting fortify: Add KUnit tests for runtime overflows ...
2024-03-11objtool: Check local label in read_unwind_hints()Tiezhu Yang
When update the latest upstream gcc and binutils, it generates some objtool warnings on LoongArch, like this: arch/loongarch/kernel/entry.o: warning: objtool: ret_from_fork+0x0: unreachable instruction We can see that the reloc sym name is local label instead of section in relocation section '.rela.discard.unwind_hints', in this case, the reloc sym type is STT_NOTYPE instead of STT_SECTION. Let us check it to not return -1, then use reloc->sym->offset instead of reloc addend which is 0 to find the corresponding instruction. Here are some detailed info: [fedora@linux 6.8.test]$ gcc --version gcc (GCC) 14.0.1 20240129 (experimental) [fedora@linux 6.8.test]$ as --version GNU assembler (GNU Binutils) 2.42.50.20240129 [fedora@linux 6.8.test]$ readelf -r arch/loongarch/kernel/entry.o | grep -A 3 "rela.discard.unwind_hints" Relocation section '.rela.discard.unwind_hints' at offset 0x3a8 contains 7 entries: Offset Info Type Sym. Value Sym. Name + Addend 000000000000 000a00000063 R_LARCH_32_PCREL 0000000000000000 .Lhere_1 + 0 00000000000c 000b00000063 R_LARCH_32_PCREL 00000000000000a8 .Lhere_50 + 0 Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-03-11objtool: Check local label in add_dead_ends()Tiezhu Yang
When update the latest upstream gcc and binutils, it generates more objtool warnings on LoongArch, like this: init/main.o: warning: objtool: unexpected relocation symbol type in .rela.discard.unreachable We can see that the reloc sym name is local label instead of section in relocation section '.rela.discard.unreachable', in this case, the reloc sym type is STT_NOTYPE instead of STT_SECTION. As suggested by Peter Zijlstra, we add a "local_label" member in struct symbol, then set it as true if symbol type is STT_NOTYPE and symbol name starts with ".L" string in classify_symbols(). Let's check reloc->sym->local_label to not return -1 in add_dead_ends(), and also use reloc->sym->offset instead of reloc addend which is 0 to find the corresponding instruction. At the same time, let's replace the variable "addend" with "offset" to reflect the reality. Here are some detailed info: [fedora@linux 6.8.test]$ gcc --version gcc (GCC) 14.0.1 20240129 (experimental) [fedora@linux 6.8.test]$ as --version GNU assembler (GNU Binutils) 2.42.50.20240129 [fedora@linux 6.8.test]$ readelf -r init/main.o | grep -A 2 "rela.discard.unreachable" Relocation section '.rela.discard.unreachable' at offset 0x6028 contains 1 entry: Offset Info Type Sym. Value Sym. Name + Addend 000000000000 00d900000063 R_LARCH_32_PCREL 00000000000002c4 .L500^B1 + 0 Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-02-29objtool: Fix UNWIND_HINT_{SAVE,RESTORE} across basic blocksJosh Poimboeuf
If SAVE and RESTORE unwind hints are in different basic blocks, and objtool sees the RESTORE before the SAVE, it errors out with: vmlinux.o: warning: objtool: vmw_port_hb_in+0x242: objtool isn't smart enough to handle this CFI save/restore combo In such a case, defer following the RESTORE block until the straight-line path gets followed later. Fixes: 8faea26e6111 ("objtool: Re-add UNWIND_HINT_{SAVE_RESTORE}") Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202402240702.zJFNmahW-lkp@intel.com/ Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/20240227073527.avcm5naavbv3cj5s@treble Signed-off-by: Kees Cook <keescook@chromium.org>
2024-01-10x86/bugs: Rename CONFIG_RETHUNK => CONFIG_MITIGATION_RETHUNKBreno Leitao
Step 10/10 of the namespace unification of CPU mitigations related Kconfig options. [ mingo: Added one more case. ] Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Breno Leitao <leitao@debian.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20231121160740.1249350-11-leitao@debian.org
2024-01-10x86/bugs: Rename CONFIG_RETPOLINE => CONFIG_MITIGATION_RETPOLINEBreno Leitao
Step 5/10 of the namespace unification of CPU mitigations related Kconfig options. [ mingo: Converted a few more uses in comments/messages as well. ] Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Breno Leitao <leitao@debian.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Ariel Miculas <amiculas@cisco.com> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20231121160740.1249350-6-leitao@debian.org
2023-11-17objtool: Fix calloc call for new -Walloc-sizeSam James
GCC 14 introduces a new -Walloc-size included in -Wextra which errors out like: ``` check.c: In function ‘cfi_alloc’: check.c:294:33: error: allocation of insufficient size ‘1’ for type ‘struct cfi_state’ with size ‘320’ [-Werror=alloc-size] 294 | struct cfi_state *cfi = calloc(sizeof(struct cfi_state), 1); | ^~~~~~ ``` The calloc prototype is: ``` void *calloc(size_t nmemb, size_t size); ``` So, just swap the number of members and size arguments to match the prototype, as we're initialising 1 struct of size `sizeof(struct ...)`. GCC then sees we're not doing anything wrong. Signed-off-by: Sam James <sam@gentoo.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/20231107205504.1470006-1-sam@gentoo.org
2023-10-20objtool: Fix return thunk patching in retpolinesJosh Poimboeuf
With CONFIG_RETHUNK enabled, the compiler replaces every RET with a tail call to a return thunk ('JMP __x86_return_thunk'). Objtool annotates all such return sites so they can be patched during boot by apply_returns(). The implementation of __x86_return_thunk() is just a bare RET. It's only meant to be used temporarily until apply_returns() patches all return sites with either a JMP to another return thunk or an actual RET. Removing the .text..__x86.return_thunk section would break objtool's detection of return sites in retpolines. Since retpolines and return thunks would land in the same section, the compiler no longer uses relocations for the intra-section jumps between the retpolines and the return thunk, causing objtool to overlook them. As a result, none of the retpolines' return sites would get patched. Each one stays at 'JMP __x86_return_thunk', effectively a bare RET. Fix it by teaching objtool to detect when a non-relocated jump target is a return thunk (or retpoline). [ bp: Massage the commit message now that the offending commit removing the .text..__x86.return_thunk section has been zapped. Still keep the objtool change here as it makes objtool more robust wrt handling such intra-TU jumps without relocations, should some toolchain and/or config generate them in the future. ] Reported-by: David Kaplan <david.kaplan@amd.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20231012024737.eg5phclogp67ik6x@treble
2023-09-12objtool: Fix _THIS_IP_ detection for cold functionsJosh Poimboeuf
Cold functions and their non-cold counterparts can use _THIS_IP_ to reference each other. Don't warn about !ENDBR in that case. Note that for GCC this is currently irrelevant in light of the following commit c27cd083cfb9 ("Compiler attributes: GCC cold function alignment workarounds") which disabled cold functions in the kernel. However this may still be possible with Clang. Fixes several warnings like the following: drivers/scsi/bnx2i/bnx2i.prelink.o: warning: objtool: bnx2i_hw_ep_disconnect+0x19d: relocation to !ENDBR: bnx2i_hw_ep_disconnect.cold+0x0 drivers/net/ipvlan/ipvlan.prelink.o: warning: objtool: ipvlan_addr4_event.cold+0x28: relocation to !ENDBR: ipvlan_addr4_event+0xda drivers/net/ipvlan/ipvlan.prelink.o: warning: objtool: ipvlan_addr6_event.cold+0x26: relocation to !ENDBR: ipvlan_addr6_event+0xb7 drivers/net/ethernet/broadcom/tg3.prelink.o: warning: objtool: tg3_set_ringparam.cold+0x17: relocation to !ENDBR: tg3_set_ringparam+0x115 drivers/net/ethernet/broadcom/tg3.prelink.o: warning: objtool: tg3_self_test.cold+0x17: relocation to !ENDBR: tg3_self_test+0x2e1 drivers/target/iscsi/cxgbit/cxgbit.prelink.o: warning: objtool: __cxgbit_free_conn.cold+0x24: relocation to !ENDBR: __cxgbit_free_conn+0xfb net/can/can.prelink.o: warning: objtool: can_rx_unregister.cold+0x2c: relocation to !ENDBR: can_rx_unregister+0x11b drivers/net/ethernet/qlogic/qed/qed.prelink.o: warning: objtool: qed_spq_post+0xc0: relocation to !ENDBR: qed_spq_post.cold+0x9a drivers/net/ethernet/qlogic/qed/qed.prelink.o: warning: objtool: qed_iwarp_ll2_comp_syn_pkt.cold+0x12f: relocation to !ENDBR: qed_iwarp_ll2_comp_syn_pkt+0x34b net/tipc/tipc.prelink.o: warning: objtool: tipc_nametbl_publish.cold+0x21: relocation to !ENDBR: tipc_nametbl_publish+0xa6 Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/d8f1ab6a23a6105bc023c132b105f245c7976be6.1694476559.git.jpoimboe@kernel.org
2023-08-17objtool/x86: Fixup frame-pointer vs rethunkPeter Zijlstra
For stack-validation of a frame-pointer build, objtool validates that every CALL instruction is preceded by a frame-setup. The new SRSO return thunks violate this with their RSB stuffing trickery. Extend the __fentry__ exception to also cover the embedded_insn case used for this. This cures: vmlinux.o: warning: objtool: srso_untrain_ret+0xd: call without frame pointer save/setup Fixes: 4ae68b26c3ab ("objtool/x86: Fix SRSO mess") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://lore.kernel.org/r/20230816115921.GH980931@hirez.programming.kicks-ass.net
2023-08-16x86/cpu: Rename original retbleed methodsPeter Zijlstra
Rename the original retbleed return thunk and untrain_ret to retbleed_return_thunk() and retbleed_untrain_ret(). No functional changes. Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230814121148.909378169@infradead.org
2023-08-16objtool/x86: Fix SRSO messPeter Zijlstra
Objtool --rethunk does two things: - it collects all (tail) call's of __x86_return_thunk and places them into .return_sites. These are typically compiler generated, but RET also emits this same. - it fudges the validation of the __x86_return_thunk symbol; because this symbol is inside another instruction, it can't actually find the instruction pointed to by the symbol offset and gets upset. Because these two things pertained to the same symbol, there was no pressing need to separate these two separate things. However, alas, along comes SRSO and more crazy things to deal with appeared. The SRSO patch itself added the following symbol names to identify as rethunk: 'srso_untrain_ret', 'srso_safe_ret' and '__ret' Where '__ret' is the old retbleed return thunk, 'srso_safe_ret' is a new similarly embedded return thunk, and 'srso_untrain_ret' is completely unrelated to anything the above does (and was only included because of that INT3 vs UD2 issue fixed previous). Clear things up by adding a second category for the embedded instruction thing. Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230814121148.704502245@infradead.org
2023-08-14x86/retpoline,kprobes: Fix position of thunk sections with CONFIG_LTO_CLANGPetr Pavlu
The linker script arch/x86/kernel/vmlinux.lds.S matches the thunk sections ".text.__x86.*" from arch/x86/lib/retpoline.S as follows: .text { [...] TEXT_TEXT [...] __indirect_thunk_start = .; *(.text.__x86.*) __indirect_thunk_end = .; [...] } Macro TEXT_TEXT references TEXT_MAIN which normally expands to only ".text". However, with CONFIG_LTO_CLANG, TEXT_MAIN becomes ".text .text.[0-9a-zA-Z_]*" which wrongly matches also the thunk sections. The output layout is then different than expected. For instance, the currently defined range [__indirect_thunk_start, __indirect_thunk_end] becomes empty. Prevent the problem by using ".." as the first separator, for example, ".text..__x86.indirect_thunk". This pattern is utilized by other explicit section names which start with one of the standard prefixes, such as ".text" or ".data", and that need to be individually selected in the linker script. [ nathan: Fix conflicts with SRSO and fold in fix issue brought up by Andrew Cooper in post-review: https://lore.kernel.org/20230803230323.1478869-1-andrew.cooper3@citrix.com ] Fixes: dc5723b02e52 ("kbuild: add support for Clang LTO") Signed-off-by: Petr Pavlu <petr.pavlu@suse.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230711091952.27944-2-petr.pavlu@suse.com
2023-06-07objtool: Free insns when doneJosh Poimboeuf
Free the decoded instructions as they're no longer needed after this point. This frees up a big chunk of heap, which will come handy when skipping the reading of DWARF section data. Link: https://lore.kernel.org/r/4d4bca1a0f869de020dac80d91f9acbf6df77eab.1685464332.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-06-07objtool: Get rid of reloc->rel[a]Josh Poimboeuf
Get the relocation entry info from the underlying rsec->data. With allyesconfig + CONFIG_DEBUG_INFO: - Before: peak heap memory consumption: 35.12G - After: peak heap memory consumption: 29.93G Link: https://lore.kernel.org/r/2be32323de6d8cc73179ee0ff14b71f4e7cefaa0.1685464332.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-06-07objtool: Get rid of reloc->jump_table_startJosh Poimboeuf
Rework the jump table logic slightly so 'jump_table_start' is no longer needed. With allyesconfig + CONFIG_DEBUG_INFO: - Before: peak heap memory consumption: 40.37G - After: peak heap memory consumption: 38.64G Link: https://lore.kernel.org/r/e1602ed8a6171ada3cfac0bd8449892ec82bd188.1685464332.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-06-07objtool: Get rid of reloc->addendJosh Poimboeuf
Get the addend from the embedded GElf_Rel[a] struct. With allyesconfig + CONFIG_DEBUG_INFO: - Before: peak heap memory consumption: 42.10G - After: peak heap memory consumption: 40.37G Link: https://lore.kernel.org/r/ad2354f95d9ddd86094e3f7687acfa0750657784.1685464332.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-06-07objtool: Get rid of reloc->typeJosh Poimboeuf
Get the type from the embedded GElf_Rel[a] struct. Link: https://lore.kernel.org/r/d1c1f8da31e4f052a2478aea585fcf355cacc53a.1685464332.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-06-07objtool: Get rid of reloc->offsetJosh Poimboeuf
Get the offset from the embedded GElf_Rel[a] struct. With allyesconfig + CONFIG_DEBUG_INFO: - Before: peak heap memory consumption: 43.83G - After: peak heap memory consumption: 42.10G Link: https://lore.kernel.org/r/2b9ec01178baa346a99522710bf2e82159412e3a.1685464332.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-06-07objtool: Add for_each_reloc()Josh Poimboeuf
Link: https://lore.kernel.org/r/dbfcb1037d8b958e52d097b67829c4c6811c24bb.1685464332.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-06-07objtool: Add elf_create_section_pair()Josh Poimboeuf
When creating an annotation section, allocate the reloc section data at the beginning. This simplifies the data model a bit and also saves memory due to the removal of malloc() in elf_rebuild_reloc_section(). With allyesconfig + CONFIG_DEBUG_INFO: - Before: peak heap memory consumption: 53.49G - After: peak heap memory consumption: 49.02G Link: https://lore.kernel.org/r/048e908f3ede9b66c15e44672b6dda992b1dae3e.1685464332.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-06-07objtool: Consolidate rel/rela handlingJosh Poimboeuf
The GElf_Rel[a] structs have more similarities than differences. It's safe to hard-code the assumptions about their shared fields as they will never change. Consolidate their handling where possible, getting rid of duplicated code. Also, at least for now we only ever create rela sections, so simplify the relocation creation code to be rela-only. Link: https://lore.kernel.org/r/dcabf6df400ca500ea929f1e4284f5e5ec0b27c8.1685464332.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-06-07objtool: Improve reloc namingJosh Poimboeuf
- The term "reloc" is overloaded to mean both "an instance of struct reloc" and "a reloc section". Change the latter to "rsec". - For variable names, use "sec" for regular sections and "rsec" for rela sections to prevent them getting mixed up. - For struct reloc variables, use "reloc" instead of "rel" everywhere for consistency. Link: https://lore.kernel.org/r/8b790e403df46f445c21003e7893b8f53b99a6f3.1685464332.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-06-07objtool: Remove flags argument from elf_create_section()Josh Poimboeuf
Simplify the elf_create_section() interface a bit by removing the flags argument. Most callers don't care about changing the section header flags. If needed, they can be modified afterwards, just like any other section header field. Link: https://lore.kernel.org/r/515235d9cf62637a14bee37bfa9169ef20065471.1685464332.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-06-07objtool: Allow stack operations in UNWIND_HINT_UNDEFINED regionsJosh Poimboeuf
If the code specified UNWIND_HINT_UNDEFINED, skip the "undefined stack state" warning due to a stack operation. Just ignore the stack op and continue to propagate the undefined state. Link: https://lore.kernel.org/r/820c5b433f17c84e8761fb7465a8d319d706b1cf.1685981486.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
generated by cgit v1.2.3 (git 2.39.1) at 2025-07-31 17:27:39 +0000