xtensa: some fixes in interrupt handler

arch/xtensa/src/common/svcall.h

@@ -0,0 +1,138 @@
+/****************************************************************************
+ * arch/xtensa/src/common/svcall.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __ARCH_XTENSA_SRC_COMMON_SVCALL_H
+#define __ARCH_XTENSA_SRC_COMMON_SVCALL_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#ifdef CONFIG_LIB_SYSCALL
+#  include <syscall.h>
+#endif
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Configuration ************************************************************/
+
+/* This logic uses three system calls {0,1,2} for context switching and one
+ * for the syscall return.  So a minimum of four syscall values must be
+ * reserved.  If CONFIG_BUILD_PROTECTED is defined, then four more syscall
+ * values must be reserved.
+ */
+
+#ifdef CONFIG_LIB_SYSCALL
+#  ifdef CONFIG_BUILD_PROTECTED
+#    ifndef CONFIG_SYS_RESERVED
+#      error "CONFIG_SYS_RESERVED must be defined to have the value 9"
+#    elif CONFIG_SYS_RESERVED != 9
+#      error "CONFIG_SYS_RESERVED must have the value 9"
+#    endif
+#  else
+#    ifndef CONFIG_SYS_RESERVED
+#      error "CONFIG_SYS_RESERVED must be defined to have the value 4"
+#    elif CONFIG_SYS_RESERVED != 4
+#      error "CONFIG_SYS_RESERVED must have the value 4"
+#    endif
+#  endif
+#endif
+
+/* Xtensa system calls ******************************************************/
+
+/* SYS call 0:
+ *
+ * int xtensa_saveusercontext(uint32_t *saveregs);
+ */
+
+#define SYS_save_context          (0)
+
+/* SYS call 1:
+ *
+ * void xtensa_fullcontextrestore(uint32_t *restoreregs) noreturn_function;
+ */
+
+#define SYS_restore_context       (1)
+
+/* SYS call 2:
+ *
+ * void xtensa_switchcontext(uint32_t *saveregs, uint32_t *restoreregs);
+ */
+
+#define SYS_switch_context        (2)
+
+#ifndef CONFIG_BUILD_FLAT
+#ifdef CONFIG_LIB_SYSCALL
+/* SYS call 3:
+ *
+ * void xtensa_syscall_return(void);
+ */
+
+#define SYS_syscall_return        (3)
+
+#ifdef CONFIG_BUILD_PROTECTED
+/* SYS call 4:
+ *
+ * void up_task_start(main_t taskentry, int argc, char *argv[])
+ *        noreturn_function;
+ */
+
+#define SYS_task_start            (4)
+/* SYS call 6:
+ *
+ * void signal_handler(_sa_sigaction_t sighand, int signo,
+ *                     siginfo_t *info, void *ucontext);
+ */
+
+#define SYS_signal_handler        (6)
+
+/* SYS call 7:
+ *
+ * void signal_handler_return(void);
+ */
+
+#define SYS_signal_handler_return (7)
+
+#endif /* CONFIG_BUILD_PROTECTED */
+
+/* SYS call 5:
+ *
+ * void up_pthread_start(pthread_trampoline_t startup,
+ *                       pthread_startroutine_t entrypt, pthread_addr_t arg)
+ *        noreturn_function
+ */
+
+#define SYS_pthread_start         (5)
+
+/* SYS call 8:
+ *
+ * void up_pthread_exit(pthread_exitroutine_t exit, void *exit_value)
+ */
+
+#define SYS_pthread_exit          (8)
+
+#endif /* !CONFIG_BUILD_FLAT */
+#endif /* CONFIG_LIB_SYSCALL */
+
+#endif /* __ARCH_XTENSA_SRC_COMMON_SVCALL_H */

arch/xtensa/src/common/xtensa.h

@@ -341,6 +341,12 @@ void xtensa_pminitialize(void);
 #  define xtensa_pminitialize()
 #endif
 
+/* Interrupt handling *******************************************************/
+
+/* Exception Handlers */
+
+int xtensa_svcall(int irq, void *context, void *arg);
+
 /* Debug ********************************************************************/
 
 #ifdef CONFIG_STACK_COLORATION

arch/xtensa/src/common/xtensa_context.S

@@ -115,7 +115,6 @@
 
 _xtensa_context_save:
 
-	s32i	a3,  a2, (4 * REG_A3)
 	s32i	a4,  a2, (4 * REG_A4)
 	s32i	a5,  a2, (4 * REG_A5)
 	s32i	a6,  a2, (4 * REG_A6)

arch/xtensa/src/common/xtensa_int_handlers.S

@@ -312,6 +312,7 @@ _xtensa_level1_handler:
 
 	s32i	a2, sp, (4 * REG_A2)
 	mov		a2, sp							      /* Address of state save on stack */
+	s32i	a3, sp, (4 * REG_A3)
 	call0	_xtensa_context_save			/* Save full register state */
 
   /* Save current SP before (possibly) overwriting it, it's the register save
@@ -415,6 +416,7 @@ _xtensa_level2_handler:
 
 	s32i	a2, sp, (4 * REG_A2)
 	mov		a2, sp							/* Address of state save on stack */
+	s32i	a3, sp, (4 * REG_A3)
 	call0	_xtensa_context_save			/* Save full register state */
 
 	/* Save current SP before (possibly) overwriting it, it's the register save
@@ -493,6 +495,7 @@ _xtensa_level3_handler:
 
 	s32i	a2, sp, (4 * REG_A2)
 	mov		a2, sp							/* Address of state save on stack */
+	s32i	a3, sp, (4 * REG_A3)
 	call0	_xtensa_context_save			/* Save full register state */
 
 	/* Save current SP before (possibly) overwriting it, it's the register save
@@ -571,6 +574,7 @@ _xtensa_level4_handler:
 
 	s32i	a2, sp, (4 * REG_A2)
 	mov		a2, sp							/* Address of state save on stack */
+	s32i	a3, sp, (4 * REG_A3)
 	call0	_xtensa_context_save			/* Save full register state */
 
 	/* Save current SP before (possibly) overwriting it, it's the register save
@@ -649,6 +653,7 @@ _xtensa_level5_handler:
 
 	s32i	a2, sp, (4 * REG_A2)
 	mov		a2, sp							/* Address of state save on stack */
+	s32i	a3, sp, (4 * REG_A3)
 	call0	_xtensa_context_save			/* Save full register state */
 
 	/* Save current SP before (possibly) overwriting it, it's the register save
@@ -727,6 +732,7 @@ _xtensa_level6_handler:
 
 	s32i	a2, sp, (4 * REG_A2)
 	mov		a2, sp							/* Address of state save on stack */
+	s32i	a3, sp, (4 * REG_A3)
 	call0	_xtensa_context_save			/* Save full register state */
 
 	/* Save current SP before (possibly) overwriting it, it's the register save

arch/xtensa/src/common/xtensa_panic.S

@@ -127,8 +127,13 @@ _xtensa_panic:
 	 */
 
 	mov		a2, sp							/* Address of state save on stack */
+	s32i	a3, sp, (4 * REG_A3)
 	call0	_xtensa_context_save			/* Save full register state */
 
+	/* Dispatch the sycall as with other interrupts. */
+
+	mov		a12, sp							/* a12 = address of register save area */
+
 	/* Switch to an interrupt stack if we have one */
 
 #if CONFIG_ARCH_INTERRUPTSTACK > 15
@@ -151,18 +156,19 @@ _xtensa_panic:
 #endif
 
 	wsr		a0, PS
+	rsync
 
 	/* Call C panic handler:  Arg1 (A2) = Exception code; Arg 2 (A3) = start
 	 * of the register save area.
 	 */
 
 #ifdef __XTENSA_CALL0_ABI__
 	rsr		a2, EXCSAVE_1
-	mov		a3, sp
+	mov		a3, a12
 	call0	xtensa_panic					/* Call xtensa_panic. Should not return */
 #else
 	rsr		a6, EXCSAVE_1
-	mov		a7, sp
+	mov		a7, a12
 	call4	xtensa_panic					/* Call xtensa_panic. Should not return */
 #endif
 

arch/xtensa/src/common/xtensa_svcall.c

@@ -0,0 +1,136 @@
+/****************************************************************************
+ * arch/xtensa/src/common/xtensa_svcall.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+#include <assert.h>
+#include <debug.h>
+
+#include <nuttx/arch.h>
+#include <arch/xtensa/xtensa_specregs.h>
+
+#include "svcall.h"
+#include "xtensa.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: xtensa_svcall
+ *
+ * Description:
+ *   This is SVCall exception handler that performs context switching
+ *
+ ****************************************************************************/
+
+int xtensa_svcall(int irq, void *context, void *arg)
+{
+  uint32_t *regs = (uint32_t *)context;
+  uint32_t cmd;
+
+  DEBUGASSERT(regs && regs == CURRENT_REGS);
+  cmd = regs[REG_A2];
+
+  /* The SVCall software interrupt is called with A2 = system call command
+   * and A3..A9 = variable number of arguments depending on the system call.
+   */
+
+#ifdef CONFIG_DEBUG_SYSCALL_INFO
+# ifndef CONFIG_DEBUG_SVCALL
+  if (cmd > SYS_switch_context)
+# endif
+    {
+      svcinfo("SVCALL Entry: regs: %p cmd: %d\n", regs, cmd);
+      svcinfo("  A0: %08x %08x %08x %08x %08x %08x %08x %08x\n",
+              regs[REG_A0],  regs[REG_A1],  regs[REG_A2],  regs[REG_A3],
+              regs[REG_A4],  regs[REG_A5],  regs[REG_A6],  regs[REG_A7]);
+      svcinfo("  A8: %08x %08x %08x %08x %08x %08x %08x %08x\n",
+              regs[REG_A8],  regs[REG_A9],  regs[REG_A10], regs[REG_A11],
+              regs[REG_A12], regs[REG_A13], regs[REG_A14], regs[REG_A15]);
+      svcinfo(" PC: %08x PS: %08x\n",
+              regs[REG_PC], regs[REG_PS]);
+    }
+#endif
+
+  /* Handle the SVCall according to the command in A2 */
+
+  switch (cmd)
+    {
+      /* A2=SYS_save_context:  This is a save context command:
+       *
+       *   int xtensa_saveusercontext(uint32_t *saveregs);
+       *
+       * At this point, the following values are saved in context:
+       *
+       *   A2 = SYS_save_context
+       *   A3 = saveregs
+       *
+       * In this case, we simply need to copy the current registers to the
+       * save register space references in the saved A3 and return.
+       */
+
+      case SYS_save_context:
+        {
+        }
+        break;
+    }
+
+  /* Report what happened.  That might difficult in the case of a context
+   * switch.
+   */
+
+#ifdef CONFIG_DEBUG_SYSCALL_INFO
+# ifndef CONFIG_DEBUG_SVCALL
+  if (cmd > SYS_switch_context)
+# else
+  if (regs != CURRENT_REGS)
+# endif
+    {
+      svcinfo("SVCall Return:\n");
+      svcinfo("  A0: %08x %08x %08x %08x %08x %08x %08x %08x\n",
+              CURRENT_REGS[REG_A0],  CURRENT_REGS[REG_A1],
+              CURRENT_REGS[REG_A2],  CURRENT_REGS[REG_A3],
+              CURRENT_REGS[REG_A4],  CURRENT_REGS[REG_A5],
+              CURRENT_REGS[REG_A6],  CURRENT_REGS[REG_A7]);
+      svcinfo("  R8: %08x %08x %08x %08x %08x %08x %08x %08x\n",
+              CURRENT_REGS[REG_A8],  CURRENT_REGS[REG_A9],
+              CURRENT_REGS[REG_A10], CURRENT_REGS[REG_A11],
+              CURRENT_REGS[REG_A12], CURRENT_REGS[REG_A13],
+              CURRENT_REGS[REG_A14], CURRENT_REGS[REG_A15]);
+      svcinfo(" PC: %08x PS: %08x\n",
+              regs[REG_PC], regs[REG_PS]);
+    }
+# ifdef CONFIG_DEBUG_SVCALL
+  else
+    {
+      svcinfo("SVCall Return: %d\n", regs[REG_A0]);
+    }
+# endif
+#endif
+
+  return OK;
+}
+