/* exceptions-asm.S -- exception handling for OpenRISC 1000.
*
* Copyright (c) 2011, 2014 Authors
*
* Contributor Julius Baxter <juliusbaxter@gmail.com>
* Contributor Stefan Wallentowitz <stefan.wallentowitz@tum.de>
*
* The authors hereby grant permission to use, copy, modify, distribute,
* and license this software and its documentation for any purpose, provided
* that existing copyright notices are retained in all copies and that this
* notice is included verbatim in any distributions. No written agreement,
* license, or royalty fee is required for any of the authorized uses.
* Modifications to this software may be copyrighted by their authors
* and need not follow the licensing terms described here, provided that
* the new terms are clearly indicated on the first page of each file where
* they apply.
*/
#include "include/or1k-asm.h"
#include "include/or1k-sprs.h"
/* -------------------------------------------------------------------------- */
/*!Generic exception handler function
*/
/* -------------------------------------------------------------------------- */
// Warning - this must be the same as specified in crt0.S
#define EXCEPTION_STACK_SIZE 136
.extern _or1k_exception_handler_table
.extern _or1k_exception_level
/* -------------------------------------------------------------------------- */
/*!Function to call appropriate exception handler
*/
/* -------------------------------------------------------------------------- */
.section .text
.global _or1k_exception_handler
.type _or1k_exception_handler,@function
/*
r3 = address of exception vector
r4 = address where exception occurred
*/
#define GPR_BUF_OFFSET(x) (x << 2)
_or1k_exception_handler:
/* Store remainder of state (r3,r4 stored in vector entry)*/
l.sw GPR_BUF_OFFSET(2)(r1),r2
l.sw GPR_BUF_OFFSET(5)(r1),r5
l.sw GPR_BUF_OFFSET(6)(r1),r6
l.sw GPR_BUF_OFFSET(7)(r1),r7
l.sw GPR_BUF_OFFSET(8)(r1),r8
l.sw GPR_BUF_OFFSET(9)(r1),r9
l.sw GPR_BUF_OFFSET(10)(r1),r10
l.sw GPR_BUF_OFFSET(11)(r1),r11
l.sw GPR_BUF_OFFSET(12)(r1),r12
l.sw GPR_BUF_OFFSET(13)(r1),r13
l.sw GPR_BUF_OFFSET(14)(r1),r14
l.sw GPR_BUF_OFFSET(15)(r1),r15
l.sw GPR_BUF_OFFSET(16)(r1),r16
l.sw GPR_BUF_OFFSET(17)(r1),r17
l.sw GPR_BUF_OFFSET(18)(r1),r18
l.sw GPR_BUF_OFFSET(19)(r1),r19
l.sw GPR_BUF_OFFSET(20)(r1),r20
l.sw GPR_BUF_OFFSET(21)(r1),r21
l.sw GPR_BUF_OFFSET(22)(r1),r22
l.sw GPR_BUF_OFFSET(23)(r1),r23
l.sw GPR_BUF_OFFSET(24)(r1),r24
l.sw GPR_BUF_OFFSET(25)(r1),r25
l.sw GPR_BUF_OFFSET(26)(r1),r26
l.sw GPR_BUF_OFFSET(27)(r1),r27
l.sw GPR_BUF_OFFSET(28)(r1),r28
l.sw GPR_BUF_OFFSET(29)(r1),r29
l.sw GPR_BUF_OFFSET(30)(r1),r30
l.sw GPR_BUF_OFFSET(31)(r1),r31
l.mfspr r14,r0,OR1K_SPR_SYS_EPCR_BASE
l.sw 0x80(r1),r14
l.mfspr r14,r0,OR1K_SPR_SYS_ESR_BASE
l.sw 0x84(r1),r14
/* Replace impure pointer for exception */
l.movhi r20,hi(_or1k_exception_impure_ptr)
l.ori r20,r20,lo(_or1k_exception_impure_ptr)
#ifdef __OR1K_MULTICORE__
l.lwz r20,0(r20)
l.mfspr r22,r0,OR1K_SPR_SYS_COREID_ADDR
l.slli r22,r22,2
l.add r20,r20,r22
#endif
l.lwz r20,0(r20)
l.movhi r21,hi(_or1k_current_impure_ptr)
l.ori r21,r21,lo(_or1k_current_impure_ptr)
#ifdef __OR1K_MULTICORE__
l.lwz r21,0(r21)
l.add r21,r21,r22
#endif
l.sw 0(r21),r20
/* Determine offset in table of exception handler using r3*/
l.andi r13,r3,0xff00
l.srli r13,r13,6
/* Substract 2 words, as we have no vector at 0 and no reset handler */
l.addi r13,r13,-8
/* r13 now contains offset in or1k_exception_handler_table for
function
*/
/* Get or1k_exception_handler_table address */
l.movhi r14,hi(_or1k_exception_handler_table)
l.ori r14,r14,lo(_or1k_exception_handler_table)
#ifdef __OR1K_MULTICORE__
/* Read the address of the array of cores */
/* r14 = (*or1k_exception_handler_table) */
l.lwz r14,0(r14)
/* Generate core offset in array (off = coreid*30*4 = coreid*120) */
/* r15 = coreid */
l.mfspr r15,r0,OR1K_SPR_SYS_COREID_ADDR
/* r16 = coreid * 128 */
l.slli r16,r15,7
/* r15 = coreid * 8 */
l.slli r15,r15,3
/* r15 = coreid*128 - coreid*8 = coreid*120 = off */
l.sub r15,r16,r15
/* r14 = (*or1k_exception_handler_table)[coreid] = r14 + off */
l.add r14,r14,r15
#endif
/* r14 now contains base of exception handler table */
/* add offset of exception vector */
l.add r14,r14,r13
/* load handler address from table */
l.lwz r13, 0(r14)
/* Check to see if this handler has been set yet */
l.sfne r13,r0
OR1K_DELAYED_NOP(OR1K_INST(l.bnf exception_exit))
/* Call exception handler, copy EPCR to r3 */
OR1K_DELAYED(
OR1K_INST(l.or r3,r4,r4),
OR1K_INST(l.jalr r13)
)
/* Restore impure pointer */
l.movhi r20,hi(_or1k_impure_ptr)
l.ori r20,r20,lo(_or1k_impure_ptr)
#ifdef __OR1K_MULTICORE__
l.lwz r20,0(r20)
l.mfspr r22,r0,OR1K_SPR_SYS_COREID_ADDR
l.slli r22,r22,2
l.add r20,r20,r22
#endif
l.lwz r20,0(r20)
l.movhi r21,hi(_or1k_current_impure_ptr)
l.ori r21,r21,lo(_or1k_current_impure_ptr)
#ifdef __OR1K_MULTICORE__
l.lwz r21,0(r21)
l.add r21,r21,r22
#endif
l.sw 0(r21),r20
/* Decrement the exception nesting level */
// Load the exception level entry
l.movhi r2,hi(_or1k_exception_level)
l.ori r2,r2,lo(_or1k_exception_level)
#ifdef __OR1K_MULTICORE__
// In multicore this is the pointer to an array
// Load pointer value
l.lwz r2,0(r2)
// Add word offset of this core's nesting level
l.add r2,r2,r22
#endif
// Load the nesting level entry
l.lwz r3,0(r2)
// Decrement nesting level
l.addi r3,r3,-1
// Store back the nesting level
l.sw 0(r2),r3
/* Restore state */
l.lwz r2,0x80(r1)
l.mtspr r0,r2,OR1K_SPR_SYS_EPCR_BASE
l.lwz r2,0x84(r1)
l.mtspr r0,r2,OR1K_SPR_SYS_ESR_BASE
l.lwz r2,GPR_BUF_OFFSET(2)(r1)
l.lwz r3,GPR_BUF_OFFSET(3)(r1)
l.lwz r4,GPR_BUF_OFFSET(4)(r1)
l.lwz r5,GPR_BUF_OFFSET(5)(r1)
l.lwz r6,GPR_BUF_OFFSET(6)(r1)
l.lwz r7,GPR_BUF_OFFSET(7)(r1)
l.lwz r8,GPR_BUF_OFFSET(8)(r1)
l.lwz r9,GPR_BUF_OFFSET(9)(r1)
l.lwz r10,GPR_BUF_OFFSET(10)(r1)
l.lwz r11,GPR_BUF_OFFSET(11)(r1)
l.lwz r12,GPR_BUF_OFFSET(12)(r1)
l.lwz r13,GPR_BUF_OFFSET(13)(r1)
l.lwz r14,GPR_BUF_OFFSET(14)(r1)
l.lwz r15,GPR_BUF_OFFSET(15)(r1)
l.lwz r16,GPR_BUF_OFFSET(16)(r1)
l.lwz r17,GPR_BUF_OFFSET(17)(r1)
l.lwz r18,GPR_BUF_OFFSET(18)(r1)
l.lwz r19,GPR_BUF_OFFSET(19)(r1)
l.lwz r20,GPR_BUF_OFFSET(20)(r1)
l.lwz r21,GPR_BUF_OFFSET(21)(r1)
l.lwz r22,GPR_BUF_OFFSET(22)(r1)
l.lwz r23,GPR_BUF_OFFSET(23)(r1)
l.lwz r24,GPR_BUF_OFFSET(24)(r1)
l.lwz r25,GPR_BUF_OFFSET(25)(r1)
l.lwz r26,GPR_BUF_OFFSET(26)(r1)
l.lwz r27,GPR_BUF_OFFSET(27)(r1)
l.lwz r28,GPR_BUF_OFFSET(28)(r1)
l.lwz r29,GPR_BUF_OFFSET(29)(r1)
l.lwz r30,GPR_BUF_OFFSET(30)(r1)
l.lwz r31,GPR_BUF_OFFSET(31)(r1)
// Restore original stack
l.lwz r1,GPR_BUF_OFFSET(1)(r1)
l.rfe
l.nop
exception_exit:
/* Exception handler not set, exit */
OR1K_DELAYED(
OR1K_INST(l.or r3,r4,r4),
OR1K_INST(l.jal exit)
)