[tip: objtool/core] arm64/cpu: Mark cpu_park_loop() and friends __noreturn

From: tip-bot2 for Josh Poimboeuf
Date: Mon Apr 17 2023 - 06:51:01 EST


The following commit has been merged into the objtool/core branch of tip:

Commit-ID: 5ab6876c7843db5fe8bef691c5fdb92518b12070
Gitweb: https://git.kernel.org/tip/5ab6876c7843db5fe8bef691c5fdb92518b12070
Author: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate: Wed, 12 Apr 2023 16:49:34 -07:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Fri, 14 Apr 2023 17:31:24 +02:00

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 <jpoimboe@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/55787d3193ea3e295ccbb097abfab0a10ae49d45.1681342859.git.jpoimboe@xxxxxxxxxx
---
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(-)

diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h
index 92963f9..e73af70 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 5733a31..07f4ea1 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 cce1167..3af3c01 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 d5d09a1..07d156f 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 4a79ba1..4bb1b8f 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)