| // kernel-vector.S - Kernel Vector for General Exceptions |
| // $Id: //depot/rel/Foxhill/dot.8/Xtensa/OS/xtos/kernel-vector.S#1 $ |
| |
| // Copyright (c) 1999-2015 Tensilica Inc. |
| // |
| // Permission is hereby granted, free of charge, to any person obtaining |
| // a copy of this software and associated documentation files (the |
| // "Software"), to deal in the Software without restriction, including |
| // without limitation the rights to use, copy, modify, merge, publish, |
| // distribute, sublicense, and/or sell copies of the Software, and to |
| // permit persons to whom the Software is furnished to do so, subject to |
| // the following conditions: |
| // |
| // The above copyright notice and this permission notice shall be included |
| // in all copies or substantial portions of the Software. |
| // |
| // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. |
| // IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY |
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| |
| /* |
| * General exceptions in kernel vector mode (PS.UM==0) go to this kernel |
| * vector. This kernel vector does very little. |
| * Under normal operation of the single-threaded runtime ("XTOS"), kernel |
| * vectored general exceptions do not occur, so nothing needs to be done. |
| * However when debugging, such as when writing exception and |
| * interrupt handlers, kernel vectored exceptions may occur. |
| * They are usually the sign of a bug, so here we take a breakpoint |
| * (if debug option enabled) or take drastic action (infinite loop) |
| * otherwise. |
| * |
| * XTOS does not allow exceptions in interrupt or exception handlers. |
| * If it did, a more elaborate kernel vector handler would be needed. |
| * See the Xtensa Microprocessor Programmer's Guide for an |
| * example of how to implement such a kernel vector handler. |
| */ |
| |
| #include <xtensa/coreasm.h> |
| #include <xtensa/config/system.h> |
| #ifdef SIMULATOR |
| #include <xtensa/simcall.h> |
| #endif |
| |
| #if XCHAL_HAVE_EXCEPTIONS && (XCHAL_HAVE_XEA1 || XCHAL_HAVE_XEA2) |
| |
| .begin literal_prefix .KernelExceptionVector |
| .section .KernelExceptionVector.text, "ax" |
| |
| .align 4 |
| .global _KernelExceptionVector |
| _KernelExceptionVector: |
| |
| # if XCHAL_HAVE_DEBUG |
| 1: break 1,0 // unexpected kernel exception |
| # elif defined(SIMULATOR) |
| wsr a2, EXCSAVE1 // save a2 where simulator expects it |
| movi a2, SYS_unhandled_kernel_exc |
| 1: simcall // let simulator/debugger report unhandled exception |
| # else |
| 1: |
| # endif |
| j 1b // infinite loop - unexpected kernel exception |
| |
| .size _KernelExceptionVector, . - _KernelExceptionVector |
| .text |
| .end literal_prefix |
| |
| #endif /* XCHAL_HAVE_EXCEPTIONS */ |
| |