- 14 Apr, 2023 22 commits
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Josh Poimboeuf authored
mpt_halt_firmware() doesn't return. Mark it as such. Fixes the following warnings: vmlinux.o: warning: objtool: mptscsih_abort+0x7f4: unreachable instruction vmlinux.o: warning: objtool: mptctl_timeout_expired+0x310: unreachable instruction Reported-by:
kernel test robot <lkp@intel.com> Reported-by:
Mark Rutland <mark.rutland@arm.com> Debugged-by:
Peter Zijlstra <peterz@infradead.org> Signed-off-by:
Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by:
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Josh Poimboeuf authored
Fixes the following warning: vmlinux.o: warning: objtool: resume_play_dead+0x21: unreachable instruction Reported-by:
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Josh Poimboeuf authored
Fixes a bunch of warnings including: vmlinux.o: warning: objtool: select_reloc_root+0x314: unreachable instruction vmlinux.o: warning: objtool: finish_inode_if_needed+0x15b1: unreachable instruction vmlinux.o: warning: objtool: get_bio_sector_nr+0x259: unreachable instruction vmlinux.o: warning: objtool: raid_wait_read_end_io+0xc26: unreachable instruction vmlinux.o: warning: objtool: raid56_parity_alloc_scrub_rbio+0x37b: unreachable instruction ... Reported-by:
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Josh Poimboeuf authored
If a global function doesn't return, and its prototype has the __noreturn attribute, its weak counterpart must also not return so that it matches the prototype and meets call site expectations. To properly follow the compiled control flow at the call sites, change the global_noreturns check to include both global and weak functions. On the other hand, if a weak function isn't in global_noreturns, assume the prototype doesn't have __noreturn. Even if the weak function doesn't return, call sites treat it like a returnable function. Fixes the following warning: kernel/sched/build_policy.o: warning: objtool: do_idle() falls through to next function play_idle_precise() Reported-by:
Miroslav Benes <mbenes@suse.cz> Link: https://lore.kernel.org/r/ede3460d63f4a65d282c86f1175bd2662c2286ba.1681342859.git.jpoimboe@kernel.org
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Josh Poimboeuf authored
In preparation for improving objtool's handling of weak noreturn functions, mark nmi_panic_self_stop() __noreturn. Signed-off-by:
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Josh Poimboeuf authored
In preparation for improving objtool's handling of weak noreturn functions, mark panic_smp_self_stop() __noreturn. Signed-off-by:
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Josh Poimboeuf authored
In preparation for marking panic_smp_self_stop() __noreturn across the kernel, first mark the arm64 implementation of cpu_park_loop() and related functions __noreturn. Signed-off-by:
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Josh Poimboeuf authored
Now that start_kernel() is __noreturn, mark its chain of callers __noreturn. Signed-off-by:
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Josh Poimboeuf authored
Now that arch_call_rest_init() is __noreturn, mark its caller start_kernel() __noreturn. Signed-off-by:
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Josh Poimboeuf authored
In preparation for improving objtool's handling of weak noreturn functions, mark start_kernel(), arch_call_rest_init(), and rest_init() __noreturn. Signed-off-by:
Nick Desaulniers <ndesaulniers@google.com> Link: https://lore.kernel.org/r/7194ed8a989a85b98d92e62df660f4a90435a723.1681342859.git.jpoimboe@kernel.org
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Josh Poimboeuf authored
Allow unwinding from prefix code by copying the CFI from the starting instruction of the corresponding function. Even when the NOPs are replaced, they're still stack-invariant instructions so the same ORC entry can be reused everywhere. Signed-off-by:
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Josh Poimboeuf authored
CFI typed functions are failing to get padded properly for CONFIG_CALL_PADDING. Signed-off-by:
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Josh Poimboeuf authored
Simplify the prefix code by moving it after validate_reachable_instructions(). Signed-off-by:
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Josh Poimboeuf authored
annotate_call_site() already sets 'insn->dead_end' for calls to dead end functions. Signed-off-by:
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Josh Poimboeuf authored
Add [sec_]for_each_sym() and use them. Signed-off-by:
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Josh Poimboeuf authored
It's easier to use and also gives easy access to the instruction's containing function, which is useful for printing that function's symbol. It will also be useful in the future for rate-limiting and disassembly of warned functions. Signed-off-by:
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Josh Poimboeuf authored
Allow specifying multiple functions on the cmdline. Note this removes the secret EXTRA_ARGS feature. While at it, spread out the awk to make it more readable. Signed-off-by:
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Josh Poimboeuf authored
With KCSAN enabled, even empty inline stubs can be out-of-lined. Force the context_tracking_guest_exit() stub inline. Fixes the following warnings: vmlinux.o: warning: objtool: vmx_vcpu_enter_exit+0x1be: call to context_tracking_guest_exit() leaves .noinstr.text section vmlinux.o: warning: objtool: svm_vcpu_enter_exit+0x85: call to context_tracking_guest_exit() leaves .noinstr.text section Signed-off-by:
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Josh Poimboeuf authored
If a function has a large stack frame, the stackleak plugin adds a call to stackleak_track_stack() after the prologue. This function may be called in uaccess-enabled code. Add it to the uaccess safe list. Fixes the following warning: vmlinux.o: warning: objtool: kasan_report+0x12: call to stackleak_track_stack() with UACCESS enabled Signed-off-by:
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Josh Poimboeuf authored
Commit 468af56a ("objtool: Support addition to set CFA base") was added as a preparatory patch for arm64 support, but that support never came. It triggers a false positive warning on x86, so just revert it for now. Fixes the following warning: vmlinux.o: warning: objtool: cdce925_regmap_i2c_write+0xdb: stack state mismatch: cfa1=4+120 cfa2=5+40 Fixes: 468af56a ("objtool: Support addition to set CFA base") Reported-by:
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Josh Poimboeuf authored
Fixes the following warning: vmlinux.o: warning: objtool: check_stackleak_irqoff+0x2b6: call to _printk() leaves .noinstr.text section Signed-off-by:
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Josh Poimboeuf authored
With KCSAN enabled, end_of_stack() can get out-of-lined. Force it inline. Fixes the following warnings: vmlinux.o: warning: objtool: check_stackleak_irqoff+0x2b: call to end_of_stack() leaves .noinstr.text section Signed-off-by:
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- 23 Mar, 2023 6 commits
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Josh Poimboeuf authored
Mark reported that the ORC unwinder incorrectly marks an unwind as reliable when the unwind terminates prematurely in the dark corners of return_to_handler() due to lack of information about the next frame. The problem is UNWIND_HINT_EMPTY is used in two different situations: 1) The end of the kernel stack unwind before hitting user entry, boot code, or fork entry 2) A blind spot in ORC coverage where the unwinder has to bail due to lack of information about the next frame The ORC unwinder has no way to tell the difference between the two. When it encounters an undefined stack state with 'end=1', it blindly marks the stack reliable, which can break the livepatch consistency model. Fix it by splitting UNWIND_HINT_EMPTY into UNWIND_HINT_UNDEFINED and UNWIND_HINT_END_OF_STACK. Reported-by:Steven Rostedt (Google) <rostedt@goodmis.org> Acked-by:
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Josh Poimboeuf authored
The ENTRY unwind hint type is serving double duty as both an empty unwind hint and an unret validation annotation. Unret validation is unrelated to unwinding. Separate it out into its own annotation. Signed-off-by:
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Josh Poimboeuf authored
Unwind hints and ORC entry types are two distinct things. Separate them out more explicitly. Signed-off-by:
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Josh Poimboeuf authored
The most important argument is 'type', make that one first. Signed-off-by:
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Josh Poimboeuf authored
They produce the needed relocations while using half the space. Signed-off-by:
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Josh Poimboeuf authored
Reduce the amount of header sync churn by splitting the shared objtool.h types into a new file. Signed-off-by:
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- 08 Mar, 2023 12 commits
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Philippe Mathieu-Daudé authored
Include <linux/cpu.h> to make sure arch_cpu_idle_dead() matches its prototype going forward. Inspired-by:
Philippe Mathieu-Daudé <philmd@linaro.org> Link: https://lore.kernel.org/r/20230214083857.50163-1-philmd@linaro.orgSigned-off-by:
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Josh Poimboeuf authored
Before commit 076cbf5d2163 ("x86/xen: don't let xen_pv_play_dead() return"), in Xen, when a previously offlined CPU was brought back online, it unexpectedly resumed execution where it left off in the middle of the idle loop. There were some hacks to make that work, but the behavior was surprising as do_idle() doesn't expect an offlined CPU to return from the dead (in arch_cpu_idle_dead()). Now that Xen has been fixed, and the arch-specific implementations of arch_cpu_idle_dead() also don't return, give it a __noreturn attribute. This will cause the compiler to complain if an arch-specific implementation might return. It also improves code generation for both caller and callee. Also fixes the following warning: vmlinux.o: warning: objtool: do_idle+0x25f: unreachable instruction Reported-by:Paul E. McKenney <paulmck@kernel.org> Tested-by:
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Josh Poimboeuf authored
arch_cpu_idle_dead() should never return. Make it so. Link: https://lore.kernel.org/r/cf5ad95eef50f7704bb30e7770c59bfe23372af7.1676358308.git.jpoimboe@kernel.orgSigned-off-by:
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Josh Poimboeuf authored
cpu_die() doesn't return. Annotate it as such. By extension this also makes arch_cpu_idle_dead() noreturn. Acked-by:
Max Filippov <jcmvbkbc@gmail.com> Link: https://lore.kernel.org/r/ad801544cab7c26a0f3bbf7cfefb67303f4cd866.1676358308.git.jpoimboe@kernel.orgSigned-off-by:
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Josh Poimboeuf authored
cpu_die() doesn't return. Make that more explicit with a BUG(). BUG() is preferable to unreachable() because BUG() is a more explicit failure mode and avoids undefined behavior like falling off the edge of the function into whatever code happens to be next. Link: https://lore.kernel.org/r/cca346b5c87693499e630291d78fb0bf12c24290.1676358308.git.jpoimboe@kernel.orgSigned-off-by:
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Josh Poimboeuf authored
play_dead() doesn't return. Annotate it as such. By extension this also makes arch_cpu_idle_dead() noreturn. Link: https://lore.kernel.org/r/f3a069e6869c51ccfdda656b76882363bc9fcfa4.1676358308.git.jpoimboe@kernel.orgSigned-off-by:
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Josh Poimboeuf authored
After commit 076cbf5d2163 ("x86/xen: don't let xen_pv_play_dead() return"), play_dead() never returns. Make that more explicit with a BUG(). BUG() is preferable to unreachable() because BUG() is a more explicit failure mode and avoids undefined behavior like falling off the edge of the function into whatever code happens to be next. Link: https://lore.kernel.org/r/11e6ac1cf10f92967882926e3ac16287b50642f2.1676358308.git.jpoimboe@kernel.orgSigned-off-by: -
Josh Poimboeuf authored
cpu_play_dead() doesn't return. Annotate it as such. By extension this also makes arch_cpu_idle_dead() noreturn. Reviewed-by:
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Josh Poimboeuf authored
Include <linux/cpu.h> to make sure arch_cpu_idle_dead() matches its prototype going forward. Link: https://lore.kernel.org/r/3d9661e97828fb464a48d4becf18f12604831903.1676358308.git.jpoimboe@kernel.orgSigned-off-by:
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Josh Poimboeuf authored
play_dead() doesn't return. Annotate it as such. By extension this also makes arch_cpu_idle_dead() noreturn. Link: https://lore.kernel.org/r/03549a74fad9f73576d57e6fc0b5102322f9cff4.1676358308.git.jpoimboe@kernel.orgSigned-off-by:
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Josh Poimboeuf authored
play_dead() doesn't return. Make that more explicit with a BUG(). BUG() is preferable to unreachable() because BUG() is a more explicit failure mode and avoids undefined behavior like falling off the edge of the function into whatever code happens to be next. Link: https://lore.kernel.org/r/d0c3ff5349adfe8fd227acc236ae2c278a05eb4c.1676358308.git.jpoimboe@kernel.orgSigned-off-by:
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Josh Poimboeuf authored
start_secondary_resume() doesn't return. Annotate it as such. By extension this also makes arch_cpu_idle_dead() noreturn. Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Reviewed-by:
Christophe Leroy <christophe.leroy@csgroup.eu> Link: https://lore.kernel.org/r/b6b2141f832d8cd8ade65f190d04b011cda5f9bb.1676358308.git.jpoimboe@kernel.orgSigned-off-by:
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