[incubator-nuttx] 04/06: arch: k210: Fix the pause handler for SMP

[masayuki]

This is an automated email from the ASF dual-hosted git repository.

masayuki pushed a commit to branch releases/10.0
in repository https://gitbox.apache.org/repos/asf/incubator-nuttx.git

commit 249dc11e0508a8ce11c93020af6e8c1627b6db3f
Author: Masayuki Ishikawa <masayuki.ishik...@gmail.com>
AuthorDate: Fri Nov 20 13:45:53 2020 +0900

    arch: k210: Fix the pause handler for SMP
    
    Summary:
    - Apply the same logic added to cxd56_cpupause.c
    
    Impact:
    - SMP only
    
    Testing:
    - Tested with maix-bit:smp (QEMU)
    - Run smp and ostest
    
    Signed-off-by: Masayuki Ishikawa <masayuki.ishik...@jp.sony.com>
---
 arch/risc-v/src/k210/k210_cpupause.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/arch/risc-v/src/k210/k210_cpupause.c 
b/arch/risc-v/src/k210/k210_cpupause.c
index 88af783..2eaa573 100644
--- a/arch/risc-v/src/k210/k210_cpupause.c
+++ b/arch/risc-v/src/k210/k210_cpupause.c
@@ -205,6 +205,7 @@ int up_cpu_paused(int cpu)
 int riscv_pause_handler(int irq, void *c, FAR void *arg)
 {
   int cpu = up_cpu_index();
+  int ret = OK;
 
   /* Clear machine software interrupt */
 
@@ -217,10 +218,21 @@ int riscv_pause_handler(int irq, void *c, FAR void *arg)
 
   if (spin_islocked(&g_cpu_paused[cpu]))
     {
-      return up_cpu_paused(cpu);
+      /* NOTE: up_cpu_paused() needs to be executed in a critical section
+       * to ensure that this CPU holds g_cpu_irqlock. However, adding
+       * a critical section in up_cpu_paused() is not a good idea,
+       * because it is also called in enter_critical_section() to break
+       * a deadlock
+       */
+
+      irqstate_t flags = enter_critical_section();
+
+      ret = up_cpu_paused(cpu);
+
+      leave_critical_section(flags);
     }
 
-  return OK;
+  return ret;
 }
 
 /****************************************************************************