[RFC PATCH 2/2] Add clang-tidy irq-balancing annotations for arm64

From: Nathan Huckleberry
Date: Tue Aug 06 2019 - 17:13:31 EST

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This patch is not intended to be merged. It simply shows the scale of
the effort involved in applying annotations in the case of intentionally
unbalanced calls to local_irq_disable.

Signed-off-by: Nathan Huckleberry <nhuck@xxxxxxxxxx>
---
arch/arm64/kernel/debug-monitors.c | 1 +
arch/arm64/kernel/machine_kexec.c | 1 +
arch/arm64/kernel/process.c | 4 ++++
arch/arm64/kernel/smp.c | 1 +
drivers/tty/sysrq.c | 1 +
include/linux/compiler_attributes.h | 7 +++++++
init/main.c | 1 +
kernel/irq/handle.c | 1 +
kernel/power/suspend.c | 2 ++
kernel/sched/core.c | 1 +
kernel/sched/fair.c | 1 +
kernel/sched/idle.c | 6 ++++++
kernel/stop_machine.c | 1 +
mm/migrate.c | 1 +
net/core/dev.c | 1 +
15 files changed, 30 insertions(+)

diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index f8719bd30850..13552daeadd7 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -221,6 +221,7 @@ static int call_step_hook(struct pt_regs *regs, unsigned int esr)
}
NOKPROBE_SYMBOL(call_step_hook);

+__unbalanced_irq
static void send_user_sigtrap(int si_code)
{
struct pt_regs *regs = current_pt_regs();
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 0df8493624e0..7880c3d336d5 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -258,6 +258,7 @@ static void machine_kexec_mask_interrupts(void)
/**
* machine_crash_shutdown - shutdown non-crashing cpus and save registers
*/
+__unbalanced_irq
void machine_crash_shutdown(struct pt_regs *regs)
{
local_irq_disable();
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 9856395ccdb7..30cec11dc82b 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -111,6 +111,7 @@ void cpu_do_idle(void)
/*
* This is our default idle handler.
*/
+__unbalanced_irq
void arch_cpu_idle(void)
{
/*
@@ -149,6 +150,7 @@ void machine_shutdown(void)
* activity (executing tasks, handling interrupts). smp_send_stop()
* achieves this.
*/
+__unbalanced_irq
void machine_halt(void)
{
local_irq_disable();
@@ -162,6 +164,7 @@ void machine_halt(void)
* achieves this. When the system power is turned off, it will take all CPUs
* with it.
*/
+__unbalanced_irq
void machine_power_off(void)
{
local_irq_disable();
@@ -179,6 +182,7 @@ void machine_power_off(void)
* executing pre-reset code, and using RAM that the primary CPU's code wishes
* to use. Implementing such co-ordination would be essentially impossible.
*/
+__unbalanced_irq
void machine_restart(char *cmd)
{
/* Disable interrupts first */
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 6dcf9607d770..78da6f7b5bcd 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -852,6 +852,7 @@ static void ipi_cpu_stop(unsigned int cpu)
static atomic_t waiting_for_crash_ipi = ATOMIC_INIT(0);
#endif

+__unbalanced_irq
static void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs)
{
#ifdef CONFIG_KEXEC_CORE
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index 573b2055173c..53bac6cb39c3 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -146,6 +146,7 @@ static struct sysrq_key_op sysrq_crash_op = {
.enable_mask = SYSRQ_ENABLE_DUMP,
};

+__unbalanced_irq
static void sysrq_handle_reboot(int key)
{
lockdep_off();
diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h
index 6b318efd8a74..e2aaff9a2017 100644
--- a/include/linux/compiler_attributes.h
+++ b/include/linux/compiler_attributes.h
@@ -253,4 +253,11 @@
*/
#define __weak __attribute__((__weak__))

+
+#if __has_attribute(__annotate__)
+# define __unbalanced_irq __attribute__((annotate("ignore_irq_balancing")))
+#else
+# define __unbalanced_irq
+#endif
+
#endif /* __LINUX_COMPILER_ATTRIBUTES_H */
diff --git a/init/main.c b/init/main.c
index 66a196c5e4c3..360a2714afe3 100644
--- a/init/main.c
+++ b/init/main.c
@@ -902,6 +902,7 @@ static inline void do_trace_initcall_finish(initcall_t fn, int ret)
}
#endif /* !TRACEPOINTS_ENABLED */

+__unbalanced_irq
int __init_or_module do_one_initcall(initcall_t fn)
{
int count = preempt_count();
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index a4ace611f47f..a74309c071b7 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -134,6 +134,7 @@ void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action)
wake_up_process(action->thread);
}

+__unbalanced_irq
irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags)
{
irqreturn_t retval = IRQ_NONE;
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 096211299c07..41bc4b9b4f0e 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -380,12 +380,14 @@ static int suspend_prepare(suspend_state_t state)
}

/* default implementation */
+__unbalanced_irq
void __weak arch_suspend_disable_irqs(void)
{
local_irq_disable();
}

/* default implementation */
+__unbalanced_irq
void __weak arch_suspend_enable_irqs(void)
{
local_irq_enable();
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 874c427742a9..465d4ef60e1a 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3366,6 +3366,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
*
* WARNING: must be called with preemption disabled!
*/
+__unbalanced_irq
static void __sched notrace __schedule(bool preempt)
{
struct task_struct *prev, *next;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index f35930f5e528..9f147a2239ac 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -9334,6 +9334,7 @@ update_next_balance(struct sched_domain *sd, unsigned long *next_balance)
* least 1 task to be running on each physical CPU where possible, and
* avoids physical / logical imbalances.
*/
+__unbalanced_irq
static int active_load_balance_cpu_stop(void *data)
{
struct rq *busiest_rq = data;
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 80940939b733..b2174f71f1aa 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -52,6 +52,7 @@ static int __init cpu_idle_nopoll_setup(char *__unused)
__setup("hlt", cpu_idle_nopoll_setup);
#endif

+__unbalanced_irq
static noinline int __cpuidle cpu_idle_poll(void)
{
rcu_idle_enter();
@@ -74,6 +75,7 @@ void __weak arch_cpu_idle_prepare(void) { }
void __weak arch_cpu_idle_enter(void) { }
void __weak arch_cpu_idle_exit(void) { }
void __weak arch_cpu_idle_dead(void) { }
+__unbalanced_irq
void __weak arch_cpu_idle(void)
{
cpu_idle_force_poll = 1;
@@ -85,6 +87,7 @@ void __weak arch_cpu_idle(void)
*
* To use when the cpuidle framework cannot be used.
*/
+__unbalanced_irq
void __cpuidle default_idle_call(void)
{
if (current_clr_polling_and_test()) {
@@ -96,6 +99,7 @@ void __cpuidle default_idle_call(void)
}
}

+__unbalanced_irq
static int call_cpuidle(struct cpuidle_driver *drv, struct cpuidle_device *dev,
int next_state)
{
@@ -126,6 +130,7 @@ static int call_cpuidle(struct cpuidle_driver *drv, struct cpuidle_device *dev,
* set, and it returns with polling set. If it ever stops polling, it
* must clear the polling bit.
*/
+__unbalanced_irq
static void cpuidle_idle_call(void)
{
struct cpuidle_device *dev = cpuidle_get_device();
@@ -222,6 +227,7 @@ static void cpuidle_idle_call(void)
*
* Called with polling cleared.
*/
+__unbalanced_irq
static void do_idle(void)
{
int cpu = smp_processor_id();
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 2b5a6754646f..1ff5f63b5f85 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -178,6 +178,7 @@ static void ack_state(struct multi_stop_data *msdata)
}

/* This is the cpu_stop function which stops the CPU. */
+__unbalanced_irq
static int multi_cpu_stop(void *data)
{
struct multi_stop_data *msdata = data;
diff --git a/mm/migrate.c b/mm/migrate.c
index f2ecc2855a12..bf2fd8e2c0f4 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -396,6 +396,7 @@ static int expected_page_refs(struct address_space *mapping, struct page *page)
* 2 for pages with a mapping
* 3 for pages with a mapping and PagePrivate/PagePrivate2 set.
*/
+__unbalanced_irq
int migrate_page_move_mapping(struct address_space *mapping,
struct page *newpage, struct page *page, enum migrate_mode mode,
int extra_count)
diff --git a/net/core/dev.c b/net/core/dev.c
index d6edd218babd..04906dc6bd00 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5885,6 +5885,7 @@ static void net_rps_send_ipi(struct softnet_data *remsd)
* net_rps_action_and_irq_enable sends any pending IPI's for rps.
* Note: called with local irq disabled, but exits with local irq enabled.
*/
+__unbalanced_irq
static void net_rps_action_and_irq_enable(struct softnet_data *sd)
{
#ifdef CONFIG_RPS
--
2.22.0.709.g102302147b-goog

Next message: David Miller: "Re: [PATCH v1 0/3] net: hisilicon: Fix a few problems with hip04_eth"
Previous message: Nathan Huckleberry: "[RFC PATCH 1/2] Add clang-tidy and static analyzer support to makefile"
In reply to: Nathan Huckleberry: "[RFC PATCH 1/2] Add clang-tidy and static analyzer support to makefile"
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