250 lines
7.5 KiB
C
250 lines
7.5 KiB
C
/****************************************************************************
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* arch/sparc/src/sparc_v8/sparc_v8_swint1.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <string.h>
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#include <syscall.h>
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#include <assert.h>
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#include <debug.h>
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#include <nuttx/sched.h>
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#include <arch/irq.h>
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#include "sparc_internal.h"
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: dispatch_syscall
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*
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* Description:
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* Call the stub function corresponding to the system call.
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*
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****************************************************************************/
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#ifdef CONFIG_BUILD_KERNEL
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static void dispatch_syscall(void) naked_function;
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static void dispatch_syscall(void)
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{
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# error "Missing logic"
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}
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#endif
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: sparc_swint1
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*
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* Description:
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* This is software interrupt 8 exception handler that performs context
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* switching and manages system calls
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*
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****************************************************************************/
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int sparc_swint1(int irq, void *context, void *arg)
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{
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uint32_t *regs = (uint32_t *)context;
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DEBUGASSERT(regs && regs == CURRENT_REGS);
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/* Software interrupt 0 is invoked with REG_A0 (REG_R4) = system call
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* command and REG_A1-3 and REG_T0-2 (REG_R5-10) = variable number of
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* arguments depending on the system call.
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*/
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#ifdef CONFIG_DEBUG_SYSCALL_INFO
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svcinfo("Entry: regs: %p cmd: %d\n", regs, regs[REG_I0]);
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up_dump_register(regs);
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#endif
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/* Handle the SWInt according to the command in $4 */
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switch (regs[REG_I0])
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{
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/* A0=SYS_save_context: This is a save context command:
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*
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* int up_saveusercontext(void *saveregs);
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*
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* At this point, the following values are saved in context:
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*
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* A0 = SYS_save_context
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* A1 = saveregs
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*
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* In this case, we simply need to copy the current registers to the
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* save register space references in the saved R1 and return.
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*/
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case SYS_save_context:
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{
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DEBUGASSERT(regs[REG_I1] != 0);
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trap_flush_task((uint32_t *)regs[REG_I1], regs);
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}
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break;
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/* A0=SYS_restore_context: This a restore context command:
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*
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* void sparc_fullcontextrestore
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* (uint32_t *restoreregs) noreturn_function;
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*
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* At this point, the following values are saved in context:
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*
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* A0 = SYS_restore_context
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* A1 = restoreregs
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*
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* In this case, we simply need to set CURRENT_REGS to restore
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* register area referenced in the saved R1. context == g_current
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* regs is the normal exception return. By setting g_current
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* regs = context[R1], we force the return to the saved context
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* referenced in $a1.
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*/
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case SYS_restore_context:
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{
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DEBUGASSERT(regs[REG_I1] != 0);
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CURRENT_REGS = (uint32_t *)regs[REG_I1];
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}
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break;
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/* A0=SYS_switch_context: This a switch context command:
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*
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* void sparc_switchcontext(uint32_t *saveregs,
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* uint32_t *restoreregs);
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*
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* At this point, the following values are saved in context:
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*
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* A0 = SYS_switch_context
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* A1 = saveregs
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* A2 = restoreregs
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*
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* In this case, we save the context registers to the save register
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* area referenced by the saved contents of R5 and then set
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* CURRENT_REGS to the save register area referenced by the saved
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* contents of R6.
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*/
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case SYS_switch_context:
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{
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DEBUGASSERT(regs[REG_I1] != 0 && regs[REG_I2] != 0);
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trap_flush_task((uint32_t *)regs[REG_I1], regs);
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/* task_flush_trap(regs,(uint32_t *)regs[REG_I2]); */
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CURRENT_REGS = (uint32_t *)regs[REG_I2];
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}
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break;
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/* R0=SYS_syscall_return: This a switch context command:
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*
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* void up_sycall_return(void);
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*
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* At this point, the following values are saved in context:
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*
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* R0 = SYS_syscall_return
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*
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* We need to restore the saved return address and return in
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* unprivileged thread mode.
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*/
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#ifdef CONFIG_BUILD_KERNEL
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case SYS_syscall_return:
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{
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struct tcb_s *rtcb = sched_self();
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int index = (int)rtcb->xcp.nsyscalls - 1;
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/* Make sure that there is a saved syscall return address. */
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DEBUGASSERT(index >= 0);
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/* Setup to return to the saved syscall return address in
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* the original mode.
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*/
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CURRENT_REGS[REG_I7] = rtcb->xcp.syscall[index].sysreturn;
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#error "Missing logic -- need to restore the original mode"
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rtcb->xcp.nsyscalls = index;
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}
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break;
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#endif
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default:
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{
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#ifdef CONFIG_BUILD_KERNEL
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struct tcb_s *rtcb = sched_self();
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int index = rtcb->xcp.nsyscalls;
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/* Verify that the SYS call number is within range */
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DEBUGASSERT(CURRENT_REGS[REG_I1] < SYS_maxsyscall);
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/* Make sure that we got here that there is a no saved syscall
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* return address. We cannot yet handle nested system calls.
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*/
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DEBUGASSERT(index < CONFIG_SYS_NNEST);
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/* Setup to return to dispatch_syscall in privileged mode. */
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rtcb->xcpsyscall[index].sysreturn = regs[REG_I7];
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#error "Missing logic -- Need to save mode"
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rtcb->xcp.nsyscalls = index + 1;
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regs[REG_I7] = (uint32_t)dispatch_syscall;
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#error "Missing logic -- Need to set privileged mode"
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/* Offset R0 to account for the reserved values */
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/* CURRENT_REGS[REG_R0] -= CONFIG_SYS_RESERVED; *//*zouboan*/
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#else
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svcerr("ERROR: Bad SYS call: %d\n", regs[REG_I1]);
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#endif
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}
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break;
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}
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/* Report what happened. That might difficult in the case of a context
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* switch
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*/
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#ifdef CONFIG_DEBUG_SYSCALL_INFO
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if (regs != CURRENT_REGS)
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{
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svcinfo("SWInt Return: Context switch!\n");
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up_dump_register(CURRENT_REGS);
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}
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else
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{
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svcinfo("SWInt Return: %d\n", regs[REG_I0]);
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}
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#endif
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return OK;
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}
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