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8d50457dfc
Most tools used for compliance and SBOM generation use SPDX identifiers This change brings us a step closer to an easy SBOM generation. Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
454 lines
13 KiB
C
454 lines
13 KiB
C
/****************************************************************************
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* arch/xtensa/src/common/xtensa_swint.c
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*
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* SPDX-License-Identifier: Apache-2.0
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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 <assert.h>
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#include <debug.h>
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#include <stdint.h>
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#include <arch/xtensa/xtensa_specregs.h>
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#include <nuttx/arch.h>
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#include <sys/syscall.h>
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#include "sched/sched.h"
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#include "chip.h"
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#include "signal/signal.h"
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#include "sched/sched.h"
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#include "xtensa.h"
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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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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struct tcb_s *tcb = this_task();
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uintptr_t *new_regs = regs;
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uint32_t cmd;
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DEBUGASSERT(regs != NULL);
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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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svcinfo("SYSCALL Entry: regs: %p cmd: %" PRIu32 "\n", regs, cmd);
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up_dump_register(regs);
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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 up_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, XCPTCONTEXT_SIZE);
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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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new_regs = (uint32_t *)regs[REG_A3];
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tcb->xcp.regs = (uint32_t *)regs[REG_A3];
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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_A4] != 0);
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new_regs = (uint32_t *)regs[REG_A4];
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}
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break;
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/* A2=SYS_syscall_return: This is a syscall return command:
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*
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* void xtensa_syscall_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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* A2 = 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_LIB_SYSCALL
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case SYS_syscall_return:
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{
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struct tcb_s *rtcb = this_task();
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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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regs[REG_PC] = rtcb->xcp.syscall[index].sysreturn;
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#ifndef CONFIG_BUILD_FLAT
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xtensa_restoreprivilege(regs, rtcb->xcp.syscall[index].int_ctx);
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#endif
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/* The return value must be in A2-A5.
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* xtensa_dispatch_syscall() temporarily moved the value into A3.
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*/
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regs[REG_A2] = regs[REG_A3];
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/* Save the new syscall nesting level */
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rtcb->xcp.nsyscalls = index;
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/* Handle any signal actions that were deferred while processing
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* the system call.
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*/
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rtcb->flags &= ~TCB_FLAG_SYSCALL;
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nxsig_unmask_pendingsignal();
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}
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break;
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#endif
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/* A2=SYS_task_start: This a user task start
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*
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* void up_task_start(main_t taskentry, int argc,
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* char *argv[]) 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_task_start
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* A3 = taskentry
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* A4 = argc
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* A5 = argv
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*/
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#ifndef CONFIG_BUILD_FLAT
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case SYS_task_start:
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{
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/* Set up to return to the user-space task start-up function in
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* unprivileged mode.
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*/
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#ifdef CONFIG_BUILD_PROTECTED
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/* Use the nxtask_startup trampoline function */
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regs[REG_PC] = (uintptr_t)USERSPACE->task_startup;
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regs[REG_A6] = regs[REG_A3]; /* Task entry */
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regs[REG_A7] = regs[REG_A4]; /* argc */
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regs[REG_A8] = regs[REG_A5]; /* argv */
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#else
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/* Start the user task directly */
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regs[REG_PC] = (uintptr_t)regs[REG_A3];
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regs[REG_A6] = regs[REG_A4]; /* argc */
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regs[REG_A7] = regs[REG_A5]; /* argv */
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#endif
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/* Execute the task in User mode */
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xtensa_lowerprivilege(regs); /* User mode */
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/* User task rotates window, so pretend task was 'call4'd */
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regs[REG_PS] = PS_UM | PS_WOE | PS_CALLINC(1);
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}
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break;
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#endif
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/* A2=SYS_pthread_start: This a user pthread start
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*
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* void up_pthread_start(pthread_startroutine_t entrypt,
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* pthread_addr_t arg) 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_pthread_start
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* A3 = startup
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* A4 = entrypt
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* A5 = arg
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*/
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#if !defined(CONFIG_BUILD_FLAT) && !defined(CONFIG_DISABLE_PTHREAD)
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case SYS_pthread_start:
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{
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/* Set up to return to the user-space pthread start-up function in
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* unprivileged mode.
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*/
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regs[REG_PC] = (uintptr_t)regs[REG_A3]; /* startup */
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/* Change the parameter ordering to match the expectation of the
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* user space pthread_startup:
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*/
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regs[REG_A6] = regs[REG_A4]; /* pthread entry */
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regs[REG_A7] = regs[REG_A5]; /* arg */
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/* Execute the pthread in User mode */
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xtensa_lowerprivilege(regs); /* User mode */
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/* Startup task rotates window, so pretend task was 'call4'd */
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regs[REG_PS] = PS_UM | PS_WOE | PS_CALLINC(1);
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}
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break;
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#endif
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/* A2=SYS_signal_handler: This a user signal handler callback
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*
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* void signal_handler(_sa_sigaction_t sighand, int signo,
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* siginfo_t *info, void *ucontext);
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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_signal_handler
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* A3 = sighand
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* A4 = signo
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* A5 = info
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* A6 = ucontext
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*/
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#ifndef CONFIG_BUILD_FLAT
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case SYS_signal_handler:
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{
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struct tcb_s *rtcb = this_task();
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/* Remember the caller's return address */
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DEBUGASSERT(rtcb->xcp.sigreturn == 0);
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rtcb->xcp.sigreturn = regs[REG_PC];
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/* Set up to return to the user-space trampoline function in
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* unprivileged mode.
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*/
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regs[REG_PC] = (uintptr_t)USERSPACE->signal_handler;
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xtensa_lowerprivilege(regs); /* User mode */
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/* Change the parameter ordering to match the expectation of struct
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* userpace_s signal_handler.
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*/
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regs[REG_A2] = regs[REG_A3]; /* sighand */
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regs[REG_A3] = regs[REG_A4]; /* signal */
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regs[REG_A4] = regs[REG_A5]; /* info */
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regs[REG_A5] = regs[REG_A6]; /* ucontext */
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}
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break;
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#endif
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/* A2=SYS_signal_handler_return: This a user signal handler callback
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*
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* void signal_handler_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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* A2 = SYS_signal_handler_return
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*/
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#ifndef CONFIG_BUILD_FLAT
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case SYS_signal_handler_return:
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{
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struct tcb_s *rtcb = this_task();
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/* Set up to return to the kernel-mode signal dispatching logic. */
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DEBUGASSERT(rtcb->xcp.sigreturn != 0);
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regs[REG_PC] = rtcb->xcp.sigreturn;
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xtensa_raiseprivilege(regs); /* Privileged mode */
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rtcb->xcp.sigreturn = 0;
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}
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break;
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#endif
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/* This is not an architecture-specific system call. If NuttX is built
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* as a standalone kernel with a system call interface, then all of the
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* additional system calls must be handled as in the default case.
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*/
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default:
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{
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#ifdef CONFIG_LIB_SYSCALL
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struct tcb_s *rtcb = this_task();
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int index = rtcb->xcp.nsyscalls;
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/* Verify that the syscall number is within range */
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DEBUGASSERT(cmd < 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 xtensa_dispatch_syscall in privileged mode. */
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rtcb->xcp.syscall[index].sysreturn = regs[REG_PC];
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#ifndef CONFIG_BUILD_FLAT
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xtensa_saveprivilege(regs, rtcb->xcp.syscall[index].int_ctx);
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#endif
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rtcb->xcp.nsyscalls = index + 1;
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regs[REG_PC] = (uintptr_t)xtensa_dispatch_syscall;
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#ifndef CONFIG_BUILD_FLAT
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xtensa_raiseprivilege(regs); /* Privileged mode */
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#endif
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/* Offset A2 to account for the reserved values */
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regs[REG_A2] -= CONFIG_SYS_RESERVED;
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/* Indicate that we are in a syscall handler. */
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rtcb->flags |= TCB_FLAG_SYSCALL;
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#else
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svcerr("ERROR: Bad SYSCALL: %" PRIu32 "\n", cmd);
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#endif
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}
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break;
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/* A2=SYS_flush_context: This flush windows to the stack:
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*
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* int xtensa_flushcontext(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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* A2 = SYS_flush_context
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*
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* In this case, we simply need to do nothing.
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* As flush the register windows to the stack has be done by
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* interrupt enter handler.
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*/
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case SYS_flush_context:
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break;
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}
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if ((tcb->xcp.regs[REG_PS] & PS_EXCM_MASK) != 0)
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{
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tcb->xcp.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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if (regs != new_regs)
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{
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svcinfo("SYSCALL Return: Context switch!\n");
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up_dump_register(new_regs);
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}
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else
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{
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svcinfo("SYSCALL Return: %" PRIu32 "\n", cmd);
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}
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#endif
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if (regs != new_regs)
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{
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restore_critical_section(this_task(), this_cpu());
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}
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return OK;
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}
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