From 9bdc61ef27db5eaac48f1cc5deb8224603e79c89 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 16 Feb 2023 10:42:01 -0800 Subject: arm64/cpu: Mark cpu_die() __noreturn MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit cpu_die() doesn't return. Annotate it as such. By extension this also makes arch_cpu_idle_dead() noreturn. Acked-by: Mark Rutland Reviewed-by: Philippe Mathieu-Daudé Link: https://lkml.kernel.org/r/20230216184157.4hup6y6mmspr2kll@treble Signed-off-by: Josh Poimboeuf --- arch/arm64/include/asm/smp.h | 2 +- arch/arm64/kernel/smp.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/arm64') diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h index fc55f5a57a06..5733a31bab08 100644 --- a/arch/arm64/include/asm/smp.h +++ b/arch/arm64/include/asm/smp.h @@ -100,7 +100,7 @@ static inline void arch_send_wakeup_ipi_mask(const struct cpumask *mask) extern int __cpu_disable(void); extern void __cpu_die(unsigned int cpu); -extern void cpu_die(void); +extern void __noreturn cpu_die(void); extern void cpu_die_early(void); static inline void cpu_park_loop(void) diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 4e8327264255..d5d09a18b4f8 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -361,7 +361,7 @@ void __cpu_die(unsigned int cpu) * Called from the idle thread for the CPU which has been shutdown. * */ -void cpu_die(void) +void __noreturn cpu_die(void) { unsigned int cpu = smp_processor_id(); const struct cpu_operations *ops = get_cpu_ops(cpu); -- cgit v1.2.3 From 071c44e4278156f18a6a56958617223b6bffa6ab Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Mon, 13 Feb 2023 23:05:58 -0800 Subject: sched/idle: Mark arch_cpu_idle_dead() __noreturn 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 Tested-by: Paul E. McKenney Link: https://lore.kernel.org/r/60d527353da8c99d4cf13b6473131d46719ed16d.1676358308.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf --- arch/arm64/kernel/process.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/arm64') diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 71d59b5abede..089ced6d6bd6 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -69,7 +69,7 @@ void (*pm_power_off)(void); EXPORT_SYMBOL_GPL(pm_power_off); #ifdef CONFIG_HOTPLUG_CPU -void arch_cpu_idle_dead(void) +void __noreturn arch_cpu_idle_dead(void) { cpu_die(); } -- cgit v1.2.3 From 5ab6876c7843db5fe8bef691c5fdb92518b12070 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Wed, 12 Apr 2023 16:49:34 -0700 Subject: arm64/cpu: Mark cpu_park_loop() and friends __noreturn 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: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/55787d3193ea3e295ccbb097abfab0a10ae49d45.1681342859.git.jpoimboe@kernel.org --- arch/arm64/include/asm/exception.h | 4 ++-- arch/arm64/include/asm/smp.h | 6 +++--- arch/arm64/kernel/entry-common.c | 2 +- arch/arm64/kernel/smp.c | 8 +++++--- arch/arm64/kernel/traps.c | 3 +-- 5 files changed, 12 insertions(+), 11 deletions(-) (limited to 'arch/arm64') diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h index 92963f98afec..e73af709cb7a 100644 --- a/arch/arm64/include/asm/exception.h +++ b/arch/arm64/include/asm/exception.h @@ -31,7 +31,7 @@ static inline unsigned long disr_to_esr(u64 disr) return esr; } -asmlinkage void handle_bad_stack(struct pt_regs *regs); +asmlinkage void __noreturn handle_bad_stack(struct pt_regs *regs); asmlinkage void el1t_64_sync_handler(struct pt_regs *regs); asmlinkage void el1t_64_irq_handler(struct pt_regs *regs); @@ -80,5 +80,5 @@ void do_el1_fpac(struct pt_regs *regs, unsigned long esr); void do_serror(struct pt_regs *regs, unsigned long esr); void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags); -void panic_bad_stack(struct pt_regs *regs, unsigned long esr, unsigned long far); +void __noreturn panic_bad_stack(struct pt_regs *regs, unsigned long esr, unsigned long far); #endif /* __ASM_EXCEPTION_H */ diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h index 5733a31bab08..07f4ea1490f4 100644 --- a/arch/arm64/include/asm/smp.h +++ b/arch/arm64/include/asm/smp.h @@ -101,9 +101,9 @@ extern int __cpu_disable(void); extern void __cpu_die(unsigned int cpu); extern void __noreturn cpu_die(void); -extern void cpu_die_early(void); +extern void __noreturn cpu_die_early(void); -static inline void cpu_park_loop(void) +static inline void __noreturn cpu_park_loop(void) { for (;;) { wfe(); @@ -123,7 +123,7 @@ static inline void update_cpu_boot_status(int val) * which calls for a kernel panic. Update the boot status and park the calling * CPU. */ -static inline void cpu_panic_kernel(void) +static inline void __noreturn cpu_panic_kernel(void) { update_cpu_boot_status(CPU_PANIC_KERNEL); cpu_park_loop(); diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index cce1167199e3..3af3c01c93a6 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -840,7 +840,7 @@ UNHANDLED(el0t, 32, error) #endif /* CONFIG_COMPAT */ #ifdef CONFIG_VMAP_STACK -asmlinkage void noinstr handle_bad_stack(struct pt_regs *regs) +asmlinkage void noinstr __noreturn handle_bad_stack(struct pt_regs *regs) { unsigned long esr = read_sysreg(esr_el1); unsigned long far = read_sysreg(far_el1); diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index d5d09a18b4f8..07d156fddb5f 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -398,7 +398,7 @@ static void __cpu_try_die(int cpu) * Kill the calling secondary CPU, early in bringup before it is turned * online. */ -void cpu_die_early(void) +void __noreturn cpu_die_early(void) { int cpu = smp_processor_id(); @@ -816,7 +816,7 @@ void arch_irq_work_raise(void) } #endif -static void local_cpu_stop(void) +static void __noreturn local_cpu_stop(void) { set_cpu_online(smp_processor_id(), false); @@ -839,7 +839,7 @@ void panic_smp_self_stop(void) static atomic_t waiting_for_crash_ipi = ATOMIC_INIT(0); #endif -static void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs) +static void __noreturn ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs) { #ifdef CONFIG_KEXEC_CORE crash_save_cpu(regs, cpu); @@ -854,6 +854,8 @@ static void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs) /* just in case */ cpu_park_loop(); +#else + BUG(); #endif } diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 4a79ba100799..4bb1b8f47298 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -863,7 +863,7 @@ void bad_el0_sync(struct pt_regs *regs, int reason, unsigned long esr) DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack) __aligned(16); -void panic_bad_stack(struct pt_regs *regs, unsigned long esr, unsigned long far) +void __noreturn panic_bad_stack(struct pt_regs *regs, unsigned long esr, unsigned long far) { unsigned long tsk_stk = (unsigned long)current->stack; unsigned long irq_stk = (unsigned long)this_cpu_read(irq_stack_ptr); @@ -905,7 +905,6 @@ void __noreturn arm64_serror_panic(struct pt_regs *regs, unsigned long esr) nmi_panic(regs, "Asynchronous SError Interrupt"); cpu_park_loop(); - unreachable(); } bool arm64_is_fatal_ras_serror(struct pt_regs *regs, unsigned long esr) -- cgit v1.2.3 From 7412a60decec2a6744cf773280ff17a0f89e8395 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Wed, 12 Apr 2023 16:49:35 -0700 Subject: cpu: Mark panic_smp_self_stop() __noreturn In preparation for improving objtool's handling of weak noreturn functions, mark panic_smp_self_stop() __noreturn. Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/92d76ab5c8bf660f04fdcd3da1084519212de248.1681342859.git.jpoimboe@kernel.org --- arch/arm64/include/asm/smp.h | 1 - arch/arm64/kernel/smp.c | 2 +- 2 files changed, 1 insertion(+), 2 deletions(-) (limited to 'arch/arm64') diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h index 07f4ea1490f4..f2d26235bfb4 100644 --- a/arch/arm64/include/asm/smp.h +++ b/arch/arm64/include/asm/smp.h @@ -143,7 +143,6 @@ bool cpus_are_stuck_in_kernel(void); extern void crash_smp_send_stop(void); extern bool smp_crash_stop_failed(void); -extern void panic_smp_self_stop(void); #endif /* ifndef __ASSEMBLY__ */ diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 07d156fddb5f..05fe797e4203 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -830,7 +830,7 @@ static void __noreturn local_cpu_stop(void) * that cpu_online_mask gets correctly updated and smp_send_stop() can skip * CPUs that have already stopped themselves. */ -void panic_smp_self_stop(void) +void __noreturn panic_smp_self_stop(void) { local_cpu_stop(); } -- cgit v1.2.3