The following commit has been merged into the x86/cpu branch of tip: Commit-ID: 4e32645cd8f97a308300623f81c902747df6b97b Gitweb: https://git.kernel.org/tip/4e32645cd8f97a308300623f81c902747df6b97b Author: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> AuthorDate: Sun, 02 Mar 2025 16:48:51 -08:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Tue, 04 Mar 2025 11:14:25 +01:00 x86/smp: Fix mwait_play_dead() and acpi_processor_ffh_play_dead() noreturn 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@xxxxxxxxxx> Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Tested-by: Paul E. McKenney <paulmck@xxxxxxxxxx> Link: https://lore.kernel.org/r/e885c6fa9e96a61471b33e48c2162d28b15b14c5.1740962711.git.jpoimboe@xxxxxxxxxx --- arch/x86/include/asm/smp.h | 4 ++-- arch/x86/kernel/acpi/cstate.c | 2 +- include/acpi/processor.h | 6 +++--- tools/objtool/noreturns.h | 2 ++ 4 files changed, 8 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h index 80f8bfd..1d3b11e 100644 --- a/arch/x86/include/asm/smp.h +++ b/arch/x86/include/asm/smp.h @@ -114,7 +114,7 @@ void wbinvd_on_cpu(int cpu); int wbinvd_on_all_cpus(void); void smp_kick_mwait_play_dead(void); -void mwait_play_dead(unsigned int eax_hint); +void __noreturn mwait_play_dead(unsigned int eax_hint); void native_smp_send_reschedule(int cpu); void native_send_call_func_ipi(const struct cpumask *mask); @@ -166,7 +166,7 @@ static inline struct cpumask *cpu_llc_shared_mask(int cpu) return (struct cpumask *)cpumask_of(0); } -static inline void mwait_play_dead(unsigned int eax_hint) { } +static inline void __noreturn mwait_play_dead(unsigned int eax_hint) { BUG(); } #endif /* CONFIG_SMP */ #ifdef CONFIG_DEBUG_NMI_SELFTEST diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c index 86c87c0..d255842 100644 --- a/arch/x86/kernel/acpi/cstate.c +++ b/arch/x86/kernel/acpi/cstate.c @@ -206,7 +206,7 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu, } EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe); -void acpi_processor_ffh_play_dead(struct acpi_processor_cx *cx) +void __noreturn acpi_processor_ffh_play_dead(struct acpi_processor_cx *cx) { unsigned int cpu = smp_processor_id(); struct cstate_entry *percpu_entry; diff --git a/include/acpi/processor.h b/include/acpi/processor.h index 63a37e7..d0eccbd 100644 --- a/include/acpi/processor.h +++ b/include/acpi/processor.h @@ -280,7 +280,7 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu, struct acpi_processor_cx *cx, struct acpi_power_register *reg); void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cstate); -void acpi_processor_ffh_play_dead(struct acpi_processor_cx *cx); +void __noreturn acpi_processor_ffh_play_dead(struct acpi_processor_cx *cx); #else static inline void acpi_processor_power_init_bm_check(struct acpi_processor_flags @@ -301,9 +301,9 @@ static inline void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx { return; } -static inline void acpi_processor_ffh_play_dead(struct acpi_processor_cx *cx) +static inline void __noreturn acpi_processor_ffh_play_dead(struct acpi_processor_cx *cx) { - return; + BUG(); } #endif diff --git a/tools/objtool/noreturns.h b/tools/objtool/noreturns.h index b217489..5a4aec4 100644 --- a/tools/objtool/noreturns.h +++ b/tools/objtool/noreturns.h @@ -16,6 +16,7 @@ NORETURN(__tdx_hypercall_failed) NORETURN(__ubsan_handle_builtin_unreachable) NORETURN(__x64_sys_exit) NORETURN(__x64_sys_exit_group) +NORETURN(acpi_processor_ffh_play_dead) NORETURN(arch_cpu_idle_dead) NORETURN(bch2_trans_in_restart_error) NORETURN(bch2_trans_restart_error) @@ -34,6 +35,7 @@ NORETURN(kunit_try_catch_throw) NORETURN(machine_real_restart) NORETURN(make_task_dead) NORETURN(mpt_halt_firmware) +NORETURN(mwait_play_dead) NORETURN(nmi_panic_self_stop) NORETURN(panic) NORETURN(panic_smp_self_stop)
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