Integrate syscall with existing svcall logic

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3472 42af7a65-404d-4744-a932-0658087f49c3

arch/arm/include/arm/syscall.h

@@ -45,7 +45,10 @@
  ****************************************************************************/
 
 #include <nuttx/config.h>
+
+#ifndef __ASSEMBLY__
 #  include <stdint.h>
+#endif
 
 /****************************************************************************
  * Pre-Processor Definitions
@@ -61,6 +64,8 @@
  * Inline functions
  ****************************************************************************/
 
+#ifndef __ASSEMBLY__
+
 /* SWI with SYS_ call number and no parameters */
 
 static inline uintptr_t sys_call0(unsigned int nbr)
@@ -221,7 +226,6 @@ static inline uintptr_t sys_call6(unsigned int nbr, uintptr_t parm1,
  * Public Function Prototypes
  ****************************************************************************/
 
-#ifndef __ASSEMBLY__
 #ifdef __cplusplus
 #define EXTERN extern "C"
 extern "C" {
@@ -233,7 +237,7 @@ extern "C" {
 #ifdef __cplusplus
 }
 #endif
-#endif
 
+#endif /* __ASSEMBLY__ */
 #endif /* __ARCH_ARM_INCLUDE_ARM_SYSCALL_H */
 

arch/arm/include/cortexm3/syscall.h

@@ -45,7 +45,10 @@
  ****************************************************************************/
 
 #include <nuttx/config.h>
+
+#ifndef __ASSEMBLY__
 #  include <stdint.h>
+#endif
 
 /****************************************************************************
  * Pro-processor Definitions
@@ -61,6 +64,8 @@
  * Inline functions
  ****************************************************************************/
 
+#ifndef __ASSEMBLY__
+
 /* SVC call with SYS_ call number and no parameters */
 
 static inline uintptr_t sys_call0(unsigned int nbr)
@@ -221,7 +226,6 @@ static inline uintptr_t sys_call6(unsigned int nbr, uintptr_t parm1,
  * Public Function Prototypes
  ****************************************************************************/
 
-#ifndef __ASSEMBLY__
 #ifdef __cplusplus
 #define EXTERN extern "C"
 extern "C" {
@@ -233,7 +237,7 @@ extern "C" {
 #ifdef __cplusplus
 }
 #endif
-#endif
 
+#endif /* __ASSEMBLY__ */
 #endif /* __ARCH_ARM_INCLUDE_CORTEXM3_SYSCALL_H */
 

arch/arm/src/cortexm3/svcall.h

@@ -0,0 +1,94 @@
+/************************************************************************************
+ * arch/arm/src/cortexm3/svcall.h
+ *
+ *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ************************************************************************************/
+
+#ifndef __ARCH_ARM_SRC_COMMON_CORTEXM_SVCALL_H
+#define __ARCH_ARM_SRC_COMMON_CORTEXM_SVCALL_H
+
+/************************************************************************************
+ * Included Files
+ ************************************************************************************/
+
+#include <nuttx/config.h>
+
+#ifdef CONFIG_NUTTX_KERNEL
+#  include <syscall.h>
+#endif
+
+/************************************************************************************
+ * Pre-processor Definitions
+ ************************************************************************************/
+
+/* Configuration ********************************************************************/
+/* This logic uses three system calls {0,1,2} for context switching.  The first three
+ * syscall values must be reserved.
+ */
+
+#ifdef CONFIG_NUTTX_KERNEL
+#  ifndef CONFIG_SYS_RESERVED
+#    error "CONFIG_SYS_RESERVED must be defined to the value 3"
+#  elif CONFIG_SYS_RESERVED != 3
+#    error "CONFIG_SYS_RESERVED must have the value 3"
+#  endif
+#endif
+
+/* Cortex M3 system calls ***********************************************************/
+
+/* SYS call 0:
+ *
+ * int up_saveusercontext(uint32_t *saveregs);
+ */
+
+#define SYS_save_context    (0)
+
+/* SYS call 1:
+ *
+ * void up_fullcontextrestore(uint32_t *restoreregs) __attribute__ ((noreturn));
+ */
+
+#define SYS_restore_context (1)
+
+/* SYS call 1:
+ *
+ * void up_switchcontext(uint32_t *saveregs, uint32_t *restoreregs);
+ */
+
+#define SYS_switch_context  (2)
+
+/************************************************************************************
+ * Inline Functions
+ ************************************************************************************/
+
+#endif  /* __ARCH_ARM_SRC_COMMON_CORTEXM_SVCALL_H */
+

arch/arm/src/cortexm3/up_fullcontextrestore.S

@@ -1,7 +1,7 @@
 /************************************************************************************
  * arch/arm/src/cortexm3/up_fullcontextrestore.S
  *
- *   Copyright (C) 2009 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2009, 2011 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -39,7 +39,9 @@
 
 #include <nuttx/config.h>
 #include <arch/irq.h>
+
 #include "nvic.h"
+#include "svcall.h"
 
 /************************************************************************************
  * Preprocessor Definitions
@@ -82,7 +84,7 @@ up_fullcontextrestore:
 	/* Perform the System call with R0=1 and R1=regs */
 
 	mov		r1, r0						/* R1: regs */
-	mov	r0, #1			/* R0: 1 means restore context */
+	mov		r0, #SYS_restore_context	/* R0: restore context */
 	svc		0							/* Force synchronous SVCall (or Hard Fault) */
 
 	/* This call should not return */

arch/arm/src/cortexm3/up_saveusercontext.S

@@ -1,7 +1,7 @@
 /************************************************************************************
  * arch/arm/src/cortexm3/up_saveusercontext.S
  *
- *   Copyright (C) 2009 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2009, 2011 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -39,7 +39,9 @@
 
 #include <nuttx/config.h>
 #include <arch/irq.h>
+
 #include "nvic.h"
+#include "svcall.h"
 
 /************************************************************************************
  * Pre-processor Definitions
@@ -84,7 +86,7 @@ up_saveusercontext:
 	/* Perform the System call with R0=0 and R1=regs */
 
 	mov		r1, r0					/* R1: regs */
-	mov	r0, #0			/* R0: 0 means save context (also return value) */
+	mov		r0, #SYS_save_context	/* R0: save context (also return value) */
 	svc		0						/* Force synchronous SVCall (or Hard Fault) */
 
 	/* There are two return conditions.  On the first return, R0 (the

arch/arm/src/cortexm3/up_svcall.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/arm/src/cortexm3/up_svcall.c
  *
- *   Copyright (C) 2009 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2009, 2011 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -45,19 +45,30 @@
 #include <debug.h>
 
 #include <arch/irq.h>
+#include <nuttx/sched.h>
 
-#include "os_internal.h"
+#ifdef CONFIG_NUTTX_KERNEL
+#  include <syscall.h>
+#endif
+
+#include "svcall.h"
 #include "up_internal.h"
 
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
 
-/* Debug output from this file may interfere with context switching! */
+/* Debug output from this file may interfere with context switching!  To get
+ * debug output you must enabled the following in your NuttX configuration:
+ *
+ * CONFIG_DEBUG and CONFIG_DEBUG_SCHED
+ *
+ * And you must explicitly define DEBUG_SVCALL below:
+ */
 
 #undef DEBUG_SVCALL         /* Define to debug SVCall */
 #ifdef DEBUG_HARDFAULTS
-# define svcdbg(format, arg...) lldbg(format, ##arg)
+# define svcdbg(format, arg...) slldbg(format, ##arg)
 #else
 # define svcdbg(x...)
 #endif
@@ -74,6 +85,118 @@
  * Private Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: up_svcall
+ *
+ * Description:
+ *   This is SVCall exception handler that performs context switching
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_NUTTX_KERNEL
+static inline void dispatch_syscall(uint32_t *regs)
+{
+  uint32_t  cmd  = regs[REG_R0];
+  FAR _TCB *rtcb = sched_self();
+  uintptr_t ret  = (uintptr_t)ERROR;
+
+  /* Verify the the SYS call number is within range */
+
+  if (cmd < SYS_maxsyscall)
+    {
+      /* Report error and return ERROR */
+
+      slldbg("ERROR: Bad SYS call: %d\n", cmd);
+    }
+  else
+    {
+      /* The index into the syscall table is offset by the number of architecture-
+       * specific reserved entries at the beginning of the SYS call number space.
+       */
+
+      int index = cmd - CONFIG_SYS_RESERVED;
+
+      /* Call the correct stub for each SYS call, based on the number of parameters */
+
+      svcdbg("Calling stub%d at %p\n", index, g_stubloopkup[index].stub0);
+
+      switch (g_stubnparms[index])
+        {
+        /* No parameters */
+
+        case 0:
+          ret = g_stublookup[index].stub0();
+          break;
+
+        /* Number of parameters: 1 */
+
+        case 1:
+          ret = g_stublookup[index].stub1(regs[REG_R1]);
+          break;
+
+        /* Number of parameters: 2 */
+
+        case 2:
+          ret = g_stublookup[index].stub2(regs[REG_R1], regs[REG_R2]);
+          break;
+
+         /* Number of parameters: 3 */
+
+       case 3:
+          ret = g_stublookup[index].stub3(regs[REG_R1], regs[REG_R2],
+                                          regs[REG_R3]);
+          break;
+
+         /* Number of parameters: 4 */
+
+       case 4:
+          ret = g_stublookup[index].stub4(regs[REG_R1], regs[REG_R2],
+                                          regs[REG_R3], regs[REG_R4]);
+          break;
+
+        /* Number of parameters: 5 */
+
+        case 5:
+          ret = g_stublookup[index].stub5(regs[REG_R1], regs[REG_R2],
+                                          regs[REG_R3], regs[REG_R4],
+                                          regs[REG_R5]);
+          break;
+
+        /* Number of parameters: 6 */
+
+        case 6:
+          ret = g_stublookup[index].stub6(regs[REG_R1], regs[REG_R2],
+                                          regs[REG_R3], regs[REG_R4],
+                                          regs[REG_R5], regs[REG_R6]);
+          break;
+
+        /* Unsupported number of paramters. Report error and return ERROR */
+
+        default:
+          slldbg("ERROR: Bad SYS call %d number parameters %d\n",
+                 cmd, g_stubnparms[index]);
+          break;
+        }
+    }
+
+  /* Set up the return vaue.  First, check if a context switch occurred. 
+   * In this case, regs will no longer be the same as current_regs.  In
+   * the case of a context switch, we will have to save the return value
+   * in the TCB where it can be returned later when the task is restarted.
+   */
+
+  if (regs != current_regs)
+    {
+      regs = rtcb->xcp.regs;
+    }
+
+  /* Then return the result in R0 */
+
+  svcdbg("Return value regs: %p value: %d\n", regs, ret);
+  regs[REG_R0] = (uint32_t)ret;
+}
+#endif
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -91,16 +214,12 @@ int up_svcall(int irq, FAR void *context)
   uint32_t *regs   = (uint32_t*)context;
 
   DEBUGASSERT(regs && regs == current_regs);
-  DEBUGASSERT(regs[REG_R1] != 0);
 
-  /* The SVCall software interrupt is called with R0 = SVC command and R1 = 
+  /* The SVCall software interrupt is called with R0 = system call command
-   * the TCB register save area.
+   * and R1..R7 =  variable number of arguments depending on the system call.
    */
 
-  svcdbg("Command: %d regs: %p R1: %08x R2: %08x\n",
+  svcdbg("SVCALL Entry: regs: %p cmd: %d\n", regs, regs[REG_R0]);
-         regs[REG_R0], regs, regs[REG_R1], regs[REG_R2]);
-
-  svcdbg("SVCall Entry:\n");
   svcdbg("  R0: %08x %08x %08x %08x %08x %08x %08x %08x\n",
          regs[REG_R0],  regs[REG_R1],  regs[REG_R2],  regs[REG_R3],
          regs[REG_R4],  regs[REG_R5],  regs[REG_R6],  regs[REG_R7]);
@@ -113,32 +232,33 @@ int up_svcall(int irq, FAR void *context)
 
   switch (regs[REG_R0])
     {
-      /* R0=0:  This is a save context command:
+      /* R0=SYS_save_context:  This is a save context command:
        *
        *   int up_saveusercontext(uint32_t *saveregs);
        *
        * At this point, the following values are saved in context:
        *
-       *   R0 = 0
+       *   R0 = SYS_save_context
        *   R1 = saveregs
        *
        * In this case, we simply need to copy the current regsters to the
        * save regiser space references in the saved R1 and return.
        */
 
-      case 0:
+      case SYS_save_context:
         {
+          DEBUGASSERT(regs[REG_R1] != 0);
           memcpy((uint32_t*)regs[REG_R1], regs, XCPTCONTEXT_SIZE);
         }
         break;
 
-      /* R0=1: This a restore context command:
+      /* R0=SYS_restore_context: This a restore context command:
        *
        *   void up_fullcontextrestore(uint32_t *restoreregs) __attribute__ ((noreturn));
        *
        * At this point, the following values are saved in context:
        *
-       *   R0 = 1
+       *   R0 = SYS_restore_context
        *   R1 = restoreregs
        *
        * In this case, we simply need to set current_regs to restore register
@@ -147,13 +267,14 @@ int up_svcall(int irq, FAR void *context)
        * the return to the saved context referenced in R1.
        */
 
-      case 1:
+      case SYS_restore_context:
         {
+          DEBUGASSERT(regs[REG_R1] != 0);
           current_regs = (uint32_t*)regs[REG_R1];
         }
         break;
 
-      /* R0=2: This a switch context command:
+      /* R0=SYS_switch_context: This a switch context command:
        *
        *   void up_switchcontext(uint32_t *saveregs, uint32_t *restoreregs);
        *
@@ -169,21 +290,33 @@ int up_svcall(int irq, FAR void *context)
        * contents of R2.
        */
 
-      case 2:
+      case SYS_switch_context:
         {
-          DEBUGASSERT(regs[REG_R2] != 0);
+          DEBUGASSERT(regs[REG_R1] != 0 && regs[REG_R2] != 0);
           memcpy((uint32_t*)regs[REG_R1], regs, XCPTCONTEXT_SIZE);
           current_regs = (uint32_t*)regs[REG_R2];
         }
         break;
 
+      /* This is not an architecture-specify system call.  If NuttX is built
+       * as a standalone kernel with a system call interface, then all of the
+       * additional system calls must be handled as in the default case.
+       */
 
       default:
-        PANIC(OSERR_INTERNAL);
+#ifdef CONFIG_NUTTX_KERNEL
+        dispatch_syscall(regs);
+#else
+        slldbg("ERROR: Bad SYS call: %d\n", regs[REG_R0]);
+#endif
         break;
     }
 
-  svcdbg("SVCall Return:\n");
+  /* Report what happened.  That might difficult in the case of a context switch */
+
+  if (regs != current_regs)
+    {
+      svcdbg("SVCall Return: Context switch!\n");
       svcdbg("  R0: %08x %08x %08x %08x %08x %08x %08x %08x\n",
              current_regs[REG_R0],  current_regs[REG_R1],  current_regs[REG_R2],  current_regs[REG_R3],
              current_regs[REG_R4],  current_regs[REG_R5],  current_regs[REG_R6],  current_regs[REG_R7]);
@@ -191,6 +324,11 @@ int up_svcall(int irq, FAR void *context)
              current_regs[REG_R8],  current_regs[REG_R9],  current_regs[REG_R10], current_regs[REG_R11],
              current_regs[REG_R12], current_regs[REG_R13], current_regs[REG_R14], current_regs[REG_R15]);
       svcdbg("  PSR=%08x\n", current_regs[REG_XPSR]);
+    }
+  else
+    {
+      svcdbg("SVCall Return: %d\n", regs[REG_R0]);
+    }
 
   return OK;
 }

arch/arm/src/cortexm3/up_switchcontext.S

@@ -1,7 +1,7 @@
 /************************************************************************************
  * arch/arm/src/cortexm3/up_switchcontext.S
  *
- *   Copyright (C) 2009-2010 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2009-2011 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -39,7 +39,9 @@
 
 #include <nuttx/config.h>
 #include <arch/irq.h>
+
 #include "nvic.h"
+#include "svcall.h"
 
 /************************************************************************************
  * Pre-processor Definitions
@@ -84,7 +86,7 @@ up_switchcontext:
 
 	mov		r2, r1					/* R2: restoreregs */
 	mov		r1, r0					/* R1: saveregs */
-	mov	r0, #2			/* R0: 2 means context switch */
+	mov		r0, #SYS_switch_context	/* R0: context switch */
 	svc		0						/* Force synchronous SVCall (or Hard Fault) */
 
 	/* This call should not return */