arch: k210: Add coloration for the idle stacks

Summary:
- This commit adds coloration for the idle stacks

Impact:
- k210 only

Testing:
- Tested with smp and nsh configs with QEMU and dev board

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

arch/risc-v/src/k210/k210_cpuidlestack.c

@@ -30,9 +30,22 @@
 #include <nuttx/sched.h>
 
 #include "riscv_internal.h"
+#include "k210_memorymap.h"
 
 #ifdef CONFIG_SMP
 
+#define SMP_STACK_MASK       7
+#define SMP_STACK_SIZE       ((CONFIG_SMP_IDLETHREAD_STACKSIZE + 7) & ~7)
+#define STACK_ISALIGNED(a)   ((uintptr_t)(a) & ~SMP_STACK_MASK)
+
+#if CONFIG_SMP_NCPUS > 1
+static FAR const uintptr_t g_cpu_stackalloc[CONFIG_SMP_NCPUS] =
+{
+    0
+  , K210_IDLESTACK1_BASE
+};
+#endif
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -83,7 +96,19 @@
 int up_cpu_idlestack(int cpu, FAR struct tcb_s *tcb, size_t stack_size)
 {
 #if CONFIG_SMP_NCPUS > 1
-  up_create_stack(tcb, stack_size, TCB_FLAG_TTYPE_KERNEL);
+  uintptr_t stack_alloc;
+
+  DEBUGASSERT(cpu > 0 && cpu < CONFIG_SMP_NCPUS && tcb != NULL &&
+              stack_size <= SMP_STACK_SIZE);
+
+  /* Get the top of the stack */
+
+  stack_alloc          = (uintptr_t)g_cpu_stackalloc[cpu];
+  DEBUGASSERT(stack_alloc != 0 && STACK_ISALIGNED(stack_alloc));
+
+  tcb->adj_stack_size  = SMP_STACK_SIZE;
+  tcb->stack_alloc_ptr = (FAR void *)stack_alloc;
+  tcb->stack_base_ptr  = tcb->stack_alloc_ptr;
 #endif
   return OK;
 }

arch/risc-v/src/k210/k210_head.S

@@ -26,6 +26,8 @@
 #include <arch/rv64gc/irq.h>
 
 #include "chip.h"
+#include "k210_memorymap.h"
+#include "riscv_internal.h"
 
 /****************************************************************************
  * Public Symbols
@@ -53,6 +55,12 @@ __start:
   j    2f
 1:
   la   sp, K210_IDLESTACK1_TOP
+
+  /* In case of single CPU config, stop here */
+
+#if !(defined CONFIG_SMP) || (CONFIG_SMP_NCPUS == 1)
+  wfi
+#endif
 2:
 
   /* Disable all interrupts (i.e. timer, external) in mie */
@@ -64,6 +72,25 @@ __start:
   la   t0, __trap_vec
   csrw mtvec, t0
 
+#ifdef CONFIG_STACK_COLORATION
+  /* t0 = start of IDLE stack; t1 = top of the stack; t2 = coloration */
+
+  bnez a0, 3f  /* a0: hartid */
+  la   t0, K210_IDLESTACK0_BASE
+  j    4f
+3:
+  la   t0, K210_IDLESTACK1_BASE
+4:
+
+  mv   t1, sp
+  li   t2, STACK_COLOR
+
+5:
+  sw   t2, 0(t0)
+  addi t0, t0, 4
+  bne  t0, t1, 5b
+#endif
+
   /* Jump to __k210_start with mhartid */
 
   j    __k210_start

arch/risc-v/src/k210/k210_memorymap.h

@@ -38,14 +38,22 @@
 /* Idle thread stack starts from _ebss */
 
 #ifndef __ASSEMBLY__
-#define K210_IDLESTACK_BASE  (uintptr_t)&_ebss
+extern uintptr_t *_default_stack_limit;
+#define K210_IDLESTACK_BASE  (uintptr_t)&_default_stack_limit
 #else
-#define K210_IDLESTACK_BASE  _ebss
+#define K210_IDLESTACK_BASE  _default_stack_limit
 #endif
 
-#define K210_IDLESTACK0_TOP  (K210_IDLESTACK_BASE + CONFIG_IDLETHREAD_STACKSIZE)
+#define K210_IDLESTACK0_BASE (K210_IDLESTACK_BASE)
-#define K210_IDLESTACK1_TOP  (K210_IDLESTACK0_TOP + CONFIG_IDLETHREAD_STACKSIZE)
+#define K210_IDLESTACK0_TOP  (K210_IDLESTACK0_BASE + CONFIG_IDLETHREAD_STACKSIZE)
 
+#define K210_IDLESTACK1_BASE (K210_IDLESTACK0_TOP)
+#define K210_IDLESTACK1_TOP  (K210_IDLESTACK1_BASE + CONFIG_IDLETHREAD_STACKSIZE)
+
+#if defined(CONFIG_SMP) && (CONFIG_SMP_NCPUS > 1)
 #define K210_IDLESTACK_TOP   (K210_IDLESTACK1_TOP)
+#else
+#define K210_IDLESTACK_TOP   (K210_IDLESTACK0_TOP)
+#endif
 
 #endif /* _ARCH_RISCV_SRC_K210_K210_MEMORYMAP_H */