[incubator-nuttx] branch master updated: arch: qemu-rv: Fix timer and IPI handling for BUILD_KERNEL+SMP

[xiaoxiang]

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


The following commit(s) were added to refs/heads/master by this push:
     new 4b6c9915fe arch: qemu-rv: Fix timer and IPI handling for 
BUILD_KERNEL+SMP
4b6c9915fe is described below

commit 4b6c9915fe33685367dc7e3fef707e3378fc7cee
Author: Masayuki Ishikawa <masayuki.ishik...@gmail.com>
AuthorDate: Sat Oct 8 15:51:12 2022 +0900

    arch: qemu-rv: Fix timer and IPI handling for BUILD_KERNEL+SMP
    
    Summary:
    - I noticed that the OS timer sometimes proceeds fast when
      a task is scheduled to run on CPUO via IPI.
    - Actually, qemu-rv implementation shares supervisor software
      interrupt for both timer and IPI on CPU0.
    - This commit fixes this issue.
    
    Impact:
    - qemu-rv only
    
    Testing:
    - Tested with qemu-6.2
    
    Signed-off-by: Masayuki Ishikawa <masayuki.ishik...@jp.sony.com>
---
 arch/risc-v/src/qemu-rv/qemu_rv_timerisr.c | 32 ++++++++++++++++++++++++++----
 1 file changed, 28 insertions(+), 4 deletions(-)

diff --git a/arch/risc-v/src/qemu-rv/qemu_rv_timerisr.c 
b/arch/risc-v/src/qemu-rv/qemu_rv_timerisr.c
index 2e8e0a6f61..1492de5a3b 100644
--- a/arch/risc-v/src/qemu-rv/qemu_rv_timerisr.c
+++ b/arch/risc-v/src/qemu-rv/qemu_rv_timerisr.c
@@ -48,11 +48,18 @@
 #define MTIMER_FREQ 10000000
 #define TICK_COUNT (10000000 / TICK_PER_SEC)
 
+#ifdef CONFIG_BUILD_KERNEL
+
 /****************************************************************************
- * Private Functions
+ * Private Data
  ****************************************************************************/
 
-#ifdef CONFIG_BUILD_KERNEL
+static uint32_t g_mtimer_cnt = 0;
+static uint32_t g_stimer_pending = false;
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
 
 /****************************************************************************
  * Name: qemu_rv_ssoft_interrupt
@@ -69,9 +76,23 @@ static int qemu_rv_ssoft_interrupt(int irq, void *context, 
void *arg)
 
   CLEAR_CSR(sip, SIP_SSIP);
 
-  /* Proceed the OS timer */
+  if (g_stimer_pending)
+    {
+      g_stimer_pending = false;
+
+      /* Proceed the OS timer */
+
+      nxsched_process_timer();
+    }
+#ifdef CONFIG_SMP
+  else
+    {
+      /* We assume IPI has been issued */
+
+      riscv_pause_handler(irq, context, arg);
+    }
+#endif
 
-  nxsched_process_timer();
   return 0;
 }
 
@@ -174,6 +195,9 @@ void qemu_rv_mtimer_interrupt(void)
   next = current + TICK_COUNT;
   putreg64(next, QEMU_RV_CLINT_MTIMECMP);
 
+  g_mtimer_cnt++;
+  g_stimer_pending = true;
+
   /* Post Supervisor Software Interrupt */
 
   SET_CSR(sip, SIP_SSIP);