212 lines
6.8 KiB
C
212 lines
6.8 KiB
C
/****************************************************************************
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* arch/xtensa/src/common/xtensa_swint.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 <assert.h>
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#include <debug.h>
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#include <nuttx/arch.h>
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#include <arch/xtensa/xtensa_specregs.h>
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#include "syscall.h"
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#include "xtensa.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: xtensa_swint
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*
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* Description:
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* This is software interrupt 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 xtensa_swint(int irq, void *context, void *arg)
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{
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uint32_t *regs = (uint32_t *)context;
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uint32_t cmd;
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#if XCHAL_CP_NUM > 0
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uintptr_t cpstate;
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uint32_t cpstate_off;
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cpstate_off = offsetof(struct xcptcontext, cpstate) -
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offsetof(struct xcptcontext, regs);
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#endif
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DEBUGASSERT(regs && regs == CURRENT_REGS);
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cmd = regs[REG_A2];
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/* The SYSCall software interrupt is called with A2 = system call command
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* and A3..A9 = variable number of arguments depending on the system call.
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*/
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#ifdef CONFIG_DEBUG_SYSCALL_INFO
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# ifndef CONFIG_DEBUG_SYSCALL
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if (cmd > SYS_switch_context)
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# endif
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{
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svcinfo("SYSCALL Entry: regs: %p cmd: %d\n", regs, cmd);
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svcinfo(" A0: %08x %08x %08x %08x %08x %08x %08x %08x\n",
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regs[REG_A0], regs[REG_A1], regs[REG_A2], regs[REG_A3],
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regs[REG_A4], regs[REG_A5], regs[REG_A6], regs[REG_A7]);
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svcinfo(" A8: %08x %08x %08x %08x %08x %08x %08x %08x\n",
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regs[REG_A8], regs[REG_A9], regs[REG_A10], regs[REG_A11],
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regs[REG_A12], regs[REG_A13], regs[REG_A14], regs[REG_A15]);
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svcinfo(" PC: %08x PS: %08x\n",
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regs[REG_PC], regs[REG_PS]);
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}
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#endif
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/* Handle the SYSCall according to the command in A2 */
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switch (cmd)
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{
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/* A2=SYS_save_context: This is a save context command:
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*
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* int xtensa_saveusercontext(uint32_t *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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* A2 = SYS_save_context
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* A3 = 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 A3 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_A3] != 0);
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memcpy((uint32_t *)regs[REG_A3], regs, (4 * XCPTCONTEXT_REGS));
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#if XCHAL_CP_NUM > 0
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cpstate = (uintptr_t)regs[REG_A3] + cpstate_off;
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xtensa_coproc_savestate((struct xtensa_cpstate_s *)cpstate);
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#endif
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}
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break;
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/* A2=SYS_restore_context: This is a restore context command:
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*
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* void xtensa_fullcontextrestore(uint32_t *restoreregs)
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* 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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* A2 = SYS_restore_context
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* A3 = 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 A3. context == CURRENT_REGS
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* is the normal exception return. By setting CURRENT_REGS =
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* context[A3], we force the return to the saved context referenced
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* in A3.
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*/
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case SYS_restore_context:
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{
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DEBUGASSERT(regs[REG_A3] != 0);
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CURRENT_REGS = (uint32_t *)regs[REG_A3];
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#if XCHAL_CP_NUM > 0
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cpstate = (uintptr_t)regs[REG_A3] + cpstate_off;
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xtensa_coproc_restorestate((struct xtensa_cpstate_s *)cpstate);
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#endif
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}
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break;
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/* A2=SYS_switch_context: This is a switch context command:
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*
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* void xtensa_switchcontext
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* (uint32_t *saveregs, 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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* A2 = SYS_switch_context
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* A3 = saveregs
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* A4 = restoreregs
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*
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* In this case, we do both: We save the context registers to the save
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* register area reference by the saved contents of A3 and then set
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* CURRENT_REGS to the save register area referenced by the saved
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* contents of A4.
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*/
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case SYS_switch_context:
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{
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DEBUGASSERT(regs[REG_A3] != 0 && regs[REG_A4] != 0);
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memcpy((uint32_t *)regs[REG_A3], regs, (4 * XCPTCONTEXT_REGS));
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CURRENT_REGS = (uint32_t *)regs[REG_A4];
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}
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break;
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}
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if ((CURRENT_REGS[REG_PS] & PS_EXCM_MASK) != 0)
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{
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CURRENT_REGS[REG_PS] &= ~PS_EXCM_MASK;
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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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# ifndef CONFIG_DEBUG_SYSCALL
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if (cmd > SYS_switch_context)
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# else
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if (regs != CURRENT_REGS)
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# endif
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{
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svcinfo("SYSCall Return:\n");
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svcinfo(" A0: %08x %08x %08x %08x %08x %08x %08x %08x\n",
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CURRENT_REGS[REG_A0], CURRENT_REGS[REG_A1],
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CURRENT_REGS[REG_A2], CURRENT_REGS[REG_A3],
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CURRENT_REGS[REG_A4], CURRENT_REGS[REG_A5],
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CURRENT_REGS[REG_A6], CURRENT_REGS[REG_A7]);
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svcinfo(" R8: %08x %08x %08x %08x %08x %08x %08x %08x\n",
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CURRENT_REGS[REG_A8], CURRENT_REGS[REG_A9],
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CURRENT_REGS[REG_A10], CURRENT_REGS[REG_A11],
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CURRENT_REGS[REG_A12], CURRENT_REGS[REG_A13],
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CURRENT_REGS[REG_A14], CURRENT_REGS[REG_A15]);
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svcinfo(" PC: %08x PS: %08x\n",
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regs[REG_PC], regs[REG_PS]);
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}
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# ifdef CONFIG_DEBUG_SYSCALL
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else
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{
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svcinfo("SYSCall Return: %d\n", regs[REG_A2]);
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}
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# endif
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#endif
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return OK;
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}
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