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/******************************************************************************
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* *
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* License Agreement *
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* *
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* Copyright (c) 2013 Altera Corporation, San Jose, California, USA. *
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* All rights reserved. *
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* *
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* Permission is hereby granted, free of charge, to any person obtaining a *
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* copy of this software and associated documentation files (the "Software"), *
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* to deal in the Software without restriction, including without limitation *
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* the rights to use, copy, modify, merge, publish, distribute, sublicense, *
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* and/or sell copies of the Software, and to permit persons to whom the *
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* Software is furnished to do so, subject to the following conditions: *
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* *
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* The above copyright notice and this permission notice shall be included in *
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* all copies or substantial portions of the Software. *
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* *
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR *
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, *
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE *
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER *
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING *
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER *
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* DEALINGS IN THE SOFTWARE. *
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* *
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* This agreement shall be governed in all respects by the laws of the State *
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* of California and by the laws of the United States of America. *
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* *
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******************************************************************************/
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/*
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* This is the code called at the beginning of the exception handler
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* to detect a likely fatal ECC error exception and then jump to
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* user-provided code to handle it.
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*
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* This code is pulled in from a .globl in alt_ecc_fatal_exception.c.
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* This scheme is used so that if a handler is never registered, then this
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* code will not appear in the generated executable, thereby improving
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* code footprint.
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*
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* This code is located in its own section that the linker script
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* explicitly mentions and ensures it gets linked at the beginning
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* of the exception handler.
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*/
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/*
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* Pull in the exception handler register save code.
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*/
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.globl alt_exception
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.section .exceptions.entry.ecc_fatal, "xa"
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/*
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* This might be handling an unrecoverable ECC error exception
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* in the register file and/or data cache.
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* Must avoid reading registers or performing load/store instructions
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* before this is determined because they could trigger another
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* unrecoverable ECC error exception and create an infinite loop.
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*
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* The EXCEPTION register is always present when ECC is present.
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* Bit 31 of this register indicates that there was an unrecoverable
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* ECC error exception in the register file and/or data cache.
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* Test this (using blt to check sign bit) to determine if this is
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* what we are dealing with. Otherwise, just do normal processing.
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*
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* Jump to an application-provided routine to handle this condition.
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* Pass in the return address in the et register in case this code
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* can clean up the ECC error and then return here (unlikely).
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*
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* Runtime stack checking can't be enabled when ECC is present
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* because they both want to use the et register.
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*/
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rdctl et, exception
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bge et, r0, alt_exception_not_ecc_fatal /* Not ECCFTL if bit 31 is 0 */
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/*
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* Load ECC fatal handler pointer into et register.
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* Using a ldwio is safe because it completely bypasses the data cache.
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*/
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movhi et, %hi(alt_exception_ecc_fatal_handler)
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ori et, et, %lo(alt_exception_ecc_fatal_handler)
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ldwio et, 0(et)
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/*
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* If ECC fatal handler pointer is not 0, assume a handler
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* has been provided by the application.
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*/
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beq et, r0, alt_exception_not_ecc_fatal
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/*
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* The et register contains the address of the ECC fatal handler.
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* Jump to this address to invoke the handler.
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*/
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jmp et
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/*
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* An ECC fatal handler can jump to this label if it able
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* to recover from the fatal error (rare) and wants to continue
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* with normal exception processing.
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*/
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.globl alt_exception_not_ecc_fatal
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alt_exception_not_ecc_fatal:
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