[PATCH v2 08/10] xen/arm: Release timer interrupts when CPU is hot-unplugged

[Mirela Simonovic <mirela.simonovic@aggios.com>]

When a CPU is hot-unplugged timer interrupts have to be released
in order to free the memory that was allocated when the interrupts
were requested (using request_irq()). The request_irq is called
for each timer interrupt when the CPU gets hotplugged
(start_secondary->init_timer_interrupt->request_irq).

Signed-off-by: Mirela Simonovic <mirela.simonovic@aggios.com>

---
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Julien Grall <julien.grall@arm.com>
---
 xen/arch/arm/smpboot.c     | 1 +
 xen/arch/arm/time.c        | 7 +++++++
 xen/include/asm-arm/time.h | 6 ++++++
 3 files changed, 14 insertions(+)

diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
index 449fefc77d..b4ed479dc6 100644
--- a/xen/arch/arm/smpboot.c
+++ b/xen/arch/arm/smpboot.c
@@ -386,6 +386,7 @@ void __cpu_disable(void)
      * in respective init interrupt functions called from start_secondary)
      */
     deinit_maintenance_interrupt();
+    deinit_timer_interrupt();
 
     /* It's now safe to remove this processor from the online map */
     cpumask_clear_cpu(cpu, &cpu_online_map);
diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
index c11fcfeadd..1d9dc16f89 100644
--- a/xen/arch/arm/time.c
+++ b/xen/arch/arm/time.c
@@ -312,6 +312,13 @@ void init_timer_interrupt(void)
     check_timer_irq_cfg(timer_irq[TIMER_PHYS_NONSECURE_PPI], "NS-physical");
 }
 
+void deinit_timer_interrupt(void)
+{
+    release_irq(timer_irq[TIMER_HYP_PPI], NULL);
+    release_irq(timer_irq[TIMER_VIRT_PPI], NULL);
+    release_irq(timer_irq[TIMER_PHYS_NONSECURE_PPI], NULL);
+}
+
 /* Wait a set number of microseconds */
 void udelay(unsigned long usecs)
 {
diff --git a/xen/include/asm-arm/time.h b/xen/include/asm-arm/time.h
index 5b9a31de91..6fa4c47532 100644
--- a/xen/include/asm-arm/time.h
+++ b/xen/include/asm-arm/time.h
@@ -34,6 +34,12 @@ unsigned int timer_get_irq(enum timer_ppi ppi);
 /* Set up the timer interrupt on this CPU */
 extern void init_timer_interrupt(void);
 
+/*
+ * Revert actions done in init_timer_interrupt that are required to properly
+ * disable this CPU.
+ */
+extern void deinit_timer_interrupt(void);
+
 /* Counter value at boot time */
 extern uint64_t boot_count;
 
-- 
2.13.0


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