text: /****************************************************************************
   * arch/mips/include/mips32/syscall.h
   *
   *   Copyright (C) 2011-2013, 2015 Gregory Nutt. All rights reserved.
   *   Author: Gregory Nutt <gnutt@nuttx.org>
   *
   * 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.
   *
   ****************************************************************************/
  
  /* This file should never be included directed but, rather, only indirectly
   * through include/syscall.h or include/sys/sycall.h
   */
  
  #ifndef __ARCH_MIPS_INCLUDE_MIPS32_SYSCALL_H
  #define __ARCH_MIPS_INCLUDE_MIPS32_SYSCALL_H
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  
  #ifndef __ASSEMBLY__
  #  include <stdint.h>
  #endif
  
  /****************************************************************************
   * Pre-processor Definitions
   ****************************************************************************/
  
  #define SYS_syscall 0x00
  
  /* Configuration ********************************************************************/
  /* SYS call 1 and 2 are defined for internal use by the PIC32MX port (see
   * arch/mips/include/mips32/syscall.h).  In addition, SYS call 3 is the return from
   * a SYS call in kernel mode.  The first four syscall values must, therefore, be
   * reserved (0 is not used).
   */
  
  #ifdef CONFIG_BUILD_KERNEL
  #  ifndef CONFIG_SYS_RESERVED
  #    error "CONFIG_SYS_RESERVED must be defined to the value 4"
  #  elif CONFIG_SYS_RESERVED != 4
  #    error "CONFIG_SYS_RESERVED must have the value 4"
  #  endif
  #endif
  
  /* sys_call macros ******************************************************************/
  /* System calls with 3 parameters and fewer are handled by sys_call0 (sys_call1,
   * sys_call2, and sys_call3 are aliases for sys_call0).  This is because the
   * parmeters are passed in a0-a3.  a0 is reserved for the syscall number leaving
   * up to thre additional parameters that can be passed in registers.  The remainder
   * would have to be pushed onto the stack.
   *
   * Instead, these macros are provided which handle parameters four, five and six in
   * a non-standard way:  The use s0 ($7), s1 ($8), and s2 ($9) to pass the additional
   * parameters.
   */
  
  #ifndef __ASSEMBLY__
  
  /* System call SYS_ argument and four additional parameters. */
  
  #define sys_call4(nbr,parm1,parm2,parm3,parm4) __extension__({ \
    uintptr_t __result; \
    __asm__ __volatile__ (\
      "\tmove	$4, %0\n" \
      "\tmove	$5, %1\n" \
      "\tmove	$6, %2\n" \
      "\tmove	$7, %3\n" \
      "\tmove	$8, %4\n" \
      "\la	$12, sys_call3\n" \
      "\jalr	$12, $31\n" \
      "\tmove	%5, $r2\n" \
      : "=r" (nbr) "=r" (parm1) "=r" (parm2) "=r" (parm3) "=r" (parm4) \
      : " "r"(__result)\
      : "memory"\
    ); \
    __result; \
  })
  
  /* System call SYS_ argument and five additional parameters. */
  
  #define sys_call5(nbr,parm1,parm2,parm3,parm4,parm5) __extension__({ \
    uintptr_t __result; \
    __asm__ __volatile__ (\
      "\tmove	$4, %0\n" \
      "\tmove	$5, %1\n" \
      "\tmove	$6, %2\n" \
      "\tmove	$7, %3\n" \
      "\tmove	$8, %4\n" \
      "\tmove	$9, %5\n" \
      "\la	$12, sys_call3\n" \
      "\jalr	$12, $31\n" \
      "\tmove	%6, $r2\n" \
      : "=r" (nbr) "=r" (parm1) "=r" (parm2) "=r" (parm3) "=r" (parm4) "=r" (parm5) \
      : " "r"(__result)\
      : "memory"\
    ); \
    __result; \
  })
  
  /* System call SYS_ argument and six additional parameters. */
  
  #define sys_call5(nbr,parm1,parm2,parm3,parm4,parm5,parm6) __extension__({ \
    uintptr_t __result; \
    __asm__ __volatile__ (\
      "\tmove	$4, %0\n" \
      "\tmove	$5, %1\n" \
      "\tmove	$6, %2\n" \
      "\tmove	$7, %3\n" \
      "\tmove	$8, %4\n" \
      "\tmove	$9, %5\n" \
      "\tmove	$10, %5\n" \
      "\la	$12, sys_call3\n" \
      "\jalr	$12, $31\n" \
      "\tmove	%6, $r2\n" \
      : "=r" (nbr) "=r" (parm1) "=r" (parm2) "=r" (parm3) "=r" (parm4) "=r" (parm5) \
      : " "r"(__result)\
      : "memory"\
    ); \
    __result; \
  })
  
  /* Context switching system calls ***************************************************/
  
  /* SYS call 0: (not used) */
  
  /* SYS call 1:
   *
   * void up_fullcontextrestore(uint32_t *restoreregs) noreturn_function;
   */
  
  #define SYS_restore_context (1)
  #define up_fullcontextrestore(restoreregs) \
    (void)sys_call1(SYS_restore_context, (uintptr_t)restoreregs)
  
  /* SYS call 2:
   *
   * void up_switchcontext(uint32_t *saveregs, uint32_t *restoreregs);
   */
  
  #define SYS_switch_context (2)
  #define up_switchcontext(saveregs, restoreregs) \
    (void)sys_call2(SYS_switch_context, (uintptr_t)saveregs, (uintptr_t)restoreregs)
  
  #ifdef CONFIG_BUILD_KERNEL
  /* SYS call 3:
   *
   * void up_syscall_return(void);
   */
  
  #define SYS_syscall_return (3)
  #define up_syscall_return() (void)sys_call0(SYS_syscall_return)
  
  #endif
  #endif /* __ASSEMBLY__ */
  
  /****************************************************************************
   * Public Types
   ****************************************************************************/
  
  /****************************************************************************
   * Inline functions
   ****************************************************************************/
  
  #ifndef __ASSEMBLY__
  
  /****************************************************************************
   * Public Variables
   ****************************************************************************/
  
  /****************************************************************************
   * Public Function Prototypes
   ****************************************************************************/
  
  #ifdef __cplusplus
  #define EXTERN extern "C"
  extern "C"
  {
  #else
  #define EXTERN extern
  #endif
  
  /****************************************************************************
   * Name: up_syscall0
   *
   * Description:
   *   System call SYS_ argument and no additional parameters.
   *
   ****************************************************************************/
  
  uintptr_t sys_call0(unsigned int nbr);
  
  /****************************************************************************
   * Name: up_syscall1
   *
   * Description:
   *   System call SYS_ argument and one additional parameter.
   *
   ****************************************************************************/
  
  uintptr_t sys_call1(unsigned int nbr, uintptr_t parm1);
  
  /****************************************************************************
   * Name: up_syscall2
   *
   * Description:
   *   System call SYS_ argument and two additional parameters.
   *
   ****************************************************************************/
  
  uintptr_t sys_call2(unsigned int nbr, uintptr_t parm1, uintptr_t parm2);
  
  /****************************************************************************
   * Name: up_syscall3
   *
   * Description:
   *   System call SYS_ argument and three additional parameters.
   *
   ****************************************************************************/
  
  uintptr_t sys_call3(unsigned int nbr, uintptr_t parm1, uintptr_t parm2,
                      uintptr_t parm3);
  
  #undef EXTERN
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* __ASSEMBLY__ */
  #endif /* __ARCH_MIPS_INCLUDE_MIPS32_SYSCALL_H */
  
  