[incubator-nuttx] 05/06: arch: xtensa: Fix the pause handler for SMP

[ma...@apache.org]

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

commit d1a6f7969c06625981077ac623d042b14944ea48
Author: Masayuki Ishikawa <ma...@gmail.com>
AuthorDate: Fri Nov 20 13:47:56 2020 +0900

    arch: xtensa: Fix the pause handler for SMP
    
    Summary:
    - Apply the same logic added to cxd56_cpupause.c
    
    Impact:
    - SMP only
    
    Testing:
    - Tested with esp32-core:smp (QEMU)
    - Run smp and ostest
    
    Signed-off-by: Masayuki Ishikawa <Ma...@jp.sony.com>
---
 arch/xtensa/src/common/xtensa_cpupause.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/xtensa/src/common/xtensa_cpupause.c b/arch/xtensa/src/common/xtensa_cpupause.c
index 5b59200..0d7c486 100644
--- a/arch/xtensa/src/common/xtensa_cpupause.c
+++ b/arch/xtensa/src/common/xtensa_cpupause.c
@@ -192,7 +192,18 @@ void xtensa_pause_handler(void)
 
   if (spin_islocked(&g_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();
+
       up_cpu_paused(cpu);
+
+      leave_critical_section(flags);
     }
 }