[patch V3 29/32] x86/irq/64: Init hardirq_stack_ptr during CPU hotplug

Thomas Gleixner
2019-04-14T16:03:51Z

Preparatory change for distangling the irq stack union as a prerequisite
for irq stacks with guard pages.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/include/asm/irq.h | 4 ----
arch/x86/kernel/cpu/common.c | 4 +---
arch/x86/kernel/irq_64.c | 15 +++++++++++++++
3 files changed, 16 insertions(+), 7 deletions(-)

--- a/arch/x86/include/asm/irq.h
+++ b/arch/x86/include/asm/irq.h
@@ -16,11 +16,7 @@ static inline int irq_canonicalize(int i
return ((irq == 2) ? 9 : irq);
}

-#ifdef CONFIG_X86_32
extern int irq_init_percpu_irqstack(unsigned int cpu);
-#else
-static inline int irq_init_percpu_irqstack(unsigned int cpu) { return 0; }
-#endif

#define __ARCH_HAS_DO_SOFTIRQ

--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1510,9 +1510,7 @@ DEFINE_PER_CPU(struct task_struct *, cur
&init_task;
EXPORT_PER_CPU_SYMBOL(current_task);

-DEFINE_PER_CPU(char *, hardirq_stack_ptr) =
- init_per_cpu_var(irq_stack_union.irq_stack) + IRQ_STACK_SIZE;
-
+DEFINE_PER_CPU(char *, hardirq_stack_ptr);
DEFINE_PER_CPU(unsigned int, irq_count) __visible = -1;

DEFINE_PER_CPU(int, __preempt_count) = INIT_PREEMPT_COUNT;
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -87,3 +87,18 @@ bool handle_irq(struct irq_desc *desc, s
generic_handle_irq_desc(desc);
return true;
}
+
+static int map_irq_stack(unsigned int cpu)
+{
+ void *va = per_cpu_ptr(irq_stack_union.irq_stack, cpu);
+
+ per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE;
+ return 0;
+}
+
+int irq_init_percpu_irqstack(unsigned int cpu)
+{
+ if (per_cpu(hardirq_stack_ptr, cpu))
+ return 0;
+ return map_irq_stack(cpu);
+}