nuttx/arch/xtensa/src/common/xtensa_panic.S
2016-12-16 09:21:44 -06:00

145 lines
4.9 KiB
ArmAsm

/****************************************************************************
* arch/xtensa/src/common/xtensa_panic.S
*
* Adapted from use in NuttX by:
*
* Copyright (C) 2016 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Derives from logic originally provided by Cadence Design Systems Inc.
*
* Copyright (c) 2006-2015 Cadence Design Systems 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
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
****************************************************************************/
.file "xtensa_panic.S"
/* NOTES on the use of 'call0' for long jumps instead of 'j':
*
* 1. This file should be assembled with the -mlongcalls option to xt-xcc.
*
* 2. The -mlongcalls compiler option causes 'call0 dest' to be expanded to
* a sequence 'l32r a0, dest' 'callx0 a0' which works regardless of the
* distance from the call to the destination. The linker then relaxes
* it back to 'call0 dest' if it determines that dest is within range.
* This allows more flexibility in locating code without the performance
* overhead of the 'l32r' literal data load in cases where the destination
* is in range of 'call0'. There is an additional benefit in that 'call0'
* has a longer range than 'j' due to the target being word-aligned, so
* the 'l32r' sequence is less likely needed.
*
* 3. The use of 'call0' with -mlongcalls requires that register a0 not be
* live at the time of the call, which is always the case for a function
* call but needs to be ensured if 'call0' is used as a jump in lieu of 'j'.
*
* 4. This use of 'call0' is independent of the C function call ABI.
*/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <arch/irq.h>
#include <arch/xtensa/core.h>
#include <arch/xtensa/xtensa_specregs.h>
#include "chip_macros.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: _xtensa_panic
*
* Description:
* Should be reached by call0 (preferable) or jump only. If call0, a0 says
* where from. If on simulator, display panic message and abort, else loop
* indefinitely.
*
* Entry Conditions:
* - A1 = Stack frame already allocated. SP points to beginning of the
* register frame.
* - A0, A1, A2, PC and PS = Already saved in the stack frame
* - A2 = Exception code
*
* Exit conditions:
* Does not return.
*
****************************************************************************/
.section HANDLER_SECTION, "ax"
.global _xtensa_panic
.type _xtensa_panic, @function
.align 4
.literal_position
.align 4
_xtensa_panic:
/* Save the exception code */
wsr a2, EXCSAVE_1
/* Save rest of interrupt context (A2=address of state save area on
* stack.
*/
mov a2, sp /* Address of state save on stack */
call0 _xtensa_context_save /* Save full register state */
/* Save exc cause and vaddr into exception frame */
rsr a0, EXCCAUSE
s32i a0, sp, (4 * REG_EXCCAUSE)
rsr a0, EXCVADDR
s32i a0, sp, (4 * REG_EXCVADDR)
/* Set up PS for C, reenable hi-pri interrupts, and clear EXCM. */
#ifdef __XTENSA_CALL0_ABI__
movi a0, PS_INTLEVEL(XCHAL_EXCM_LEVEL) | PS_UM
#else
movi a0, PS_INTLEVEL(XCHAL_EXCM_LEVEL) | PS_UM | PS_WOE
#endif
wsr a0, PS
/* Call C panic handler: Arg1 (A2) = Exception code; Arg 2 (A3) = start
* of the register save area.
*/
#ifdef __XTENSA_CALL0_ABI__
rsr a2, EXCSAVE_1
mov a3, sp
call0 xtensa_panic /* Call xtensa_panic. Should not return */
#else
rsr a6, EXCSAVE_1
mov a7, sp
call4 xtensa_panic /* Call xtensa_panic. Should not return */
#endif
1: j 1b /* loop infinitely */
retw