spinlock: Remove SP_SECTION

Summary:
- SP_SECTION was introduced to allocate spinlock in non-cachable
  region mainly for Cortex-A to stabilize the NuttX SMP kernel
- However, all spinlocks are now allocated in cachable area and
  works without any problems
- So SP_SECTION should be removed to simplify the kernel code

Impact:
- None

Testing:
- Build test only

Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>

arch/arm/src/armv7-a/arm_cpupause.c

@@ -55,8 +55,8 @@
  * so that it will be ready for the next pause operation.
  */
 
-static volatile spinlock_t g_cpu_wait[CONFIG_SMP_NCPUS] SP_SECTION;
-static volatile spinlock_t g_cpu_paused[CONFIG_SMP_NCPUS] SP_SECTION;
+static volatile spinlock_t g_cpu_wait[CONFIG_SMP_NCPUS];
+static volatile spinlock_t g_cpu_paused[CONFIG_SMP_NCPUS];
 
 /****************************************************************************
  * Public Functions

arch/xtensa/src/common/xtensa_cpupause.c

@@ -40,8 +40,8 @@
  * Private Data
  ****************************************************************************/
 
-static spinlock_t g_cpu_wait[CONFIG_SMP_NCPUS] SP_SECTION;
-static spinlock_t g_cpu_paused[CONFIG_SMP_NCPUS] SP_SECTION;
+static spinlock_t g_cpu_wait[CONFIG_SMP_NCPUS];
+static spinlock_t g_cpu_paused[CONFIG_SMP_NCPUS];
 
 /****************************************************************************
  * Public Functions

arch/xtensa/src/esp32/esp32_cpustart.c

@@ -49,7 +49,7 @@
  ****************************************************************************/
 
 static volatile bool g_appcpu_started;
-static volatile spinlock_t g_appcpu_interlock SP_SECTION;
+static volatile spinlock_t g_appcpu_interlock;
 
 /****************************************************************************
  * ROM function prototypes

include/nuttx/spinlock.h

@@ -81,18 +81,6 @@ typedef struct
 #  define __SP_UNLOCK_FUNCTION 1
 #endif
 
-/* If the target CPU supports a data cache then it may be necessary to
- * manage spinlocks in a special way, perhaps linking them all into a
- * special non-cacheable memory region.
- *
- *   SP_SECTION - Special storage attributes may be required to force
- *      spinlocks into a special, non-cacheable section.
- */
-
-#if !defined(SP_SECTION)
-#  define SP_SECTION
-#endif
-
 /****************************************************************************
  * Public Function Prototypes
  ****************************************************************************/

sched/irq/irq.h

@@ -110,12 +110,12 @@ extern const irq_mapped_t g_irqmap[NR_IRQS];
  * disabled.
  */
 
-extern volatile spinlock_t g_cpu_irqlock SP_SECTION;
+extern volatile spinlock_t g_cpu_irqlock;
 
 /* Used to keep track of which CPU(s) hold the IRQ lock. */
 
-extern volatile spinlock_t g_cpu_irqsetlock SP_SECTION;
-extern volatile cpu_set_t g_cpu_irqset SP_SECTION;
+extern volatile spinlock_t g_cpu_irqsetlock;
+extern volatile cpu_set_t g_cpu_irqset;
 
 /* Handles nested calls to enter_critical section from interrupt handlers */
 

sched/irq/irq_csection.c

@@ -45,12 +45,12 @@
  * disabled.
  */
 
-volatile spinlock_t g_cpu_irqlock SP_SECTION = SP_UNLOCKED;
+volatile spinlock_t g_cpu_irqlock = SP_UNLOCKED;
 
 /* Used to keep track of which CPU(s) hold the IRQ lock. */
 
-volatile spinlock_t g_cpu_irqsetlock SP_SECTION;
-volatile cpu_set_t g_cpu_irqset SP_SECTION;
+volatile spinlock_t g_cpu_irqsetlock;
+volatile cpu_set_t g_cpu_irqset;
 
 /* Handles nested calls to enter_critical section from interrupt handlers */
 

sched/irq/irq_spinlock.c

@@ -38,7 +38,7 @@
 
 /* Used for access control */
 
-static volatile spinlock_t g_irq_spin SP_SECTION = SP_UNLOCKED;
+static volatile spinlock_t g_irq_spin = SP_UNLOCKED;
 
 /* Handles nested calls to spin_lock_irqsave and spin_unlock_irqrestore */
 

sched/sched/sched.h

@@ -337,16 +337,16 @@ extern volatile uint32_t g_cpuload_total;
  *    least one CPU has pre-emption disabled.
  */
 
-extern volatile spinlock_t g_cpu_schedlock SP_SECTION;
+extern volatile spinlock_t g_cpu_schedlock;
 
 /* Used to keep track of which CPU(s) hold the IRQ lock. */
 
-extern volatile spinlock_t g_cpu_locksetlock SP_SECTION;
-extern volatile cpu_set_t g_cpu_lockset SP_SECTION;
+extern volatile spinlock_t g_cpu_locksetlock;
+extern volatile cpu_set_t g_cpu_lockset;
 
 /* Used to lock tasklist to prevent from concurrent access */
 
-extern volatile spinlock_t g_cpu_tasklistlock SP_SECTION;
+extern volatile spinlock_t g_cpu_tasklistlock;
 
 #endif /* CONFIG_SMP */
 

sched/sched/sched_lock.c

@@ -97,12 +97,12 @@
  *    least one CPU has pre-emption disabled.
  */
 
-volatile spinlock_t g_cpu_schedlock SP_SECTION = SP_UNLOCKED;
+volatile spinlock_t g_cpu_schedlock = SP_UNLOCKED;
 
 /* Used to keep track of which CPU(s) hold the IRQ lock. */
 
-volatile spinlock_t g_cpu_locksetlock SP_SECTION;
-volatile cpu_set_t g_cpu_lockset SP_SECTION;
+volatile spinlock_t g_cpu_locksetlock;
+volatile cpu_set_t g_cpu_lockset;
 
 #endif /* CONFIG_SMP */