From b99ba04a8ceb7025c9db10c5bb5f730cad1b2cc9 Mon Sep 17 00:00:00 2001
From: zhuyanlin <zhuyanlin1@xiaomi.com>
Date: Wed, 11 May 2022 10:47:38 +0800
Subject: [PATCH] arch:xtensa: Add SYS_flush_context syscall

This syscall do nothing as flush context was done in interrupt handler.

Signed-off-by: zhuyanlin <zhuyanlin1@xiaomi.com>
---
 arch/xtensa/include/syscall.h         | 21 ++++++++++++++-------
 arch/xtensa/src/common/xtensa_swint.c | 17 +++++++++++++++++
 2 files changed, 31 insertions(+), 7 deletions(-)

diff --git a/arch/xtensa/include/syscall.h b/arch/xtensa/include/syscall.h
index 2e82543d32..2df4cac41e 100644
--- a/arch/xtensa/include/syscall.h
+++ b/arch/xtensa/include/syscall.h
@@ -91,9 +91,9 @@
  */
 
 #ifndef CONFIG_BUILD_FLAT
-#  define CONFIG_SYS_RESERVED 8
+#  define CONFIG_SYS_RESERVED 9
 #else
-#  define CONFIG_SYS_RESERVED 4
+#  define CONFIG_SYS_RESERVED 5
 #endif
 
 /* Xtensa system calls ******************************************************/
@@ -119,6 +119,13 @@
 
 #define SYS_switch_context        (2)
 
+/* SYS call 3:
+ *
+ * void xtensa_flushcontext(void);
+ */
+
+#define SYS_flush_context         (3)
+
 #ifdef CONFIG_LIB_SYSCALL
 
 /* SYS call 3:
@@ -126,7 +133,7 @@
  * void xtensa_syscall_return(void);
  */
 
-#define SYS_syscall_return        (3)
+#define SYS_syscall_return        (4)
 #endif /* CONFIG_LIB_SYSCALL */
 
 #ifndef CONFIG_BUILD_FLAT
@@ -136,7 +143,7 @@
  *        noreturn_function;
  */
 
-#define SYS_task_start            (4)
+#define SYS_task_start            (5)
 
 /* SYS call 5:
  *
@@ -145,7 +152,7 @@
  *        noreturn_function
  */
 
-#define SYS_pthread_start         (5)
+#define SYS_pthread_start         (6)
 
 /* SYS call 6:
  *
@@ -153,14 +160,14 @@
  *                     siginfo_t *info, void *ucontext);
  */
 
-#define SYS_signal_handler        (6)
+#define SYS_signal_handler        (7)
 
 /* SYS call 7:
  *
  * void signal_handler_return(void);
  */
 
-#define SYS_signal_handler_return (7)
+#define SYS_signal_handler_return (8)
 #endif /* !CONFIG_BUILD_FLAT */
 
 /****************************************************************************
diff --git a/arch/xtensa/src/common/xtensa_swint.c b/arch/xtensa/src/common/xtensa_swint.c
index d9a69927d7..45ae1b04f0 100644
--- a/arch/xtensa/src/common/xtensa_swint.c
+++ b/arch/xtensa/src/common/xtensa_swint.c
@@ -165,6 +165,23 @@ int xtensa_swint(int irq, void *context, void *arg)
           CURRENT_REGS = (uint32_t *)regs[REG_A4];
         }
 
+        break;
+
+      /* A2=SYS_flush_context:  This flush windows to the stack:
+       *
+       * int xtensa_flushcontext(void);
+       *
+       * At this point, the following values are saved in context:
+       *
+       *   A2 = SYS_flush_context
+       *
+       * In this case, we simply need to do nothing.
+       * As flush the register windows to the stack has be done by
+       * interrupt enter handler.
+       */
+
+      case SYS_flush_context:
+
         break;
     }