| 1 | /*
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| 2 | * Copyright (C) 2003-2004 Jakub Jermar
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| 3 | * All rights reserved.
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| 4 | *
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| 5 | * Redistribution and use in source and binary forms, with or without
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| 6 | * modification, are permitted provided that the following conditions
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| 7 | * are met:
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| 8 | *
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| 9 | * - Redistributions of source code must retain the above copyright
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| 10 | * notice, this list of conditions and the following disclaimer.
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| 11 | * - Redistributions in binary form must reproduce the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer in the
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| 13 | * documentation and/or other materials provided with the distribution.
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| 14 | * - The name of the author may not be used to endorse or promote products
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| 15 | * derived from this software without specific prior written permission.
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| 16 | *
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 27 | */
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| 28 |
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| 29 | #include <arch/exception.h>
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| 30 | #include <arch/interrupt.h>
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| 31 | #include <panic.h>
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| 32 | #include <arch/cp0.h>
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| 33 | #include <arch/types.h>
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| 34 | #include <arch.h>
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| 35 | #include <debug.h>
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| 36 |
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| 37 | void exception(struct exception_regdump *pstate)
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| 38 | {
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| 39 | int excno;
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| 40 | __u32 epc_shift = 0;
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| 41 |
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| 42 | ASSERT(CPU != NULL);
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| 43 |
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| 44 | /*
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| 45 | * NOTE ON OPERATION ORDERING
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| 46 | *
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| 47 | * On entry, cpu_priority_high() must be called before
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| 48 | * exception bit is cleared.
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| 49 | */
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| 50 |
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| 51 | cpu_priority_high();
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| 52 | cp0_status_write(cp0_status_read() & ~ (cp0_status_exl_exception_bit |
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| 53 | cp0_status_um_bit));
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| 54 |
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| 55 | /* Save pstate so that the threads can access it */
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| 56 | /* If THREAD->pstate is set, this is nested exception,
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| 57 | * do not rewrite it
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| 58 | */
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| 59 | if (THREAD && !THREAD->pstate)
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| 60 | THREAD->pstate = pstate;
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| 61 |
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| 62 | /* decode exception number and process the exception */
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| 63 | switch (excno = (cp0_cause_read() >> 2) & 0x1f) {
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| 64 | case EXC_Int:
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| 65 | interrupt();
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| 66 | break;
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| 67 | case EXC_TLBL:
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| 68 | case EXC_TLBS:
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| 69 | tlb_invalid(pstate);
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| 70 | break;
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| 71 | case EXC_CpU:
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| 72 | #ifdef FPU_LAZY
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| 73 | scheduler_fpu_lazy_request();
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| 74 | #else
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| 75 | panic("unhandled Coprocessor Unusable Exception\n");
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| 76 | #endif
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| 77 | break;
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| 78 | case EXC_Mod:
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| 79 | panic("unhandled TLB Modification Exception\n");
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| 80 | break;
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| 81 | case EXC_AdEL:
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| 82 | panic("unhandled Address Error Exception - load or instruction fetch\n");
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| 83 | break;
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| 84 | case EXC_AdES:
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| 85 | panic("unhandled Address Error Exception - store\n");
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| 86 | break;
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| 87 | case EXC_IBE:
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| 88 | panic("unhandled Bus Error Exception - fetch instruction\n");
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| 89 | break;
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| 90 | case EXC_DBE:
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| 91 | panic("unhandled Bus Error Exception - data reference: load or store\n");
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| 92 | break;
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| 93 | case EXC_Bp:
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| 94 | /* it is necessary to not re-execute BREAK instruction after returning from Exception handler
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| 95 | (see page 138 in R4000 Manual for more information) */
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| 96 | epc_shift = 4;
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| 97 | break;
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| 98 | case EXC_RI:
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| 99 | panic("unhandled Reserved Instruction Exception\n");
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| 100 | break;
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| 101 | case EXC_Ov:
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| 102 | panic("unhandled Arithmetic Overflow Exception\n");
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| 103 | break;
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| 104 | case EXC_Tr:
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| 105 | panic("unhandled Trap Exception\n");
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| 106 | break;
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| 107 | case EXC_VCEI:
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| 108 | panic("unhandled Virtual Coherency Exception - instruction\n");
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| 109 | break;
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| 110 | case EXC_FPE:
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| 111 | panic("unhandled Floating-Point Exception\n");
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| 112 | break;
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| 113 | case EXC_WATCH:
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| 114 | panic("unhandled reference to WatchHi/WatchLo address\n");
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| 115 | break;
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| 116 | case EXC_VCED:
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| 117 | panic("unhandled Virtual Coherency Exception - data\n");
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| 118 | break;
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| 119 | default:
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| 120 | panic("unhandled exception %d\n", excno);
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| 121 | }
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| 122 |
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| 123 | pstate->epc += epc_shift;
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| 124 | /* Set to NULL, so that we can still support nested
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| 125 | * exceptions
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| 126 | * TODO: We should probably set EXL bit before this command,
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| 127 | * nesting. On the other hand, if some exception occurs between
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| 128 | * here and ERET, it won't set anything on the pstate anyway.
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| 129 | */
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| 130 | if (THREAD)
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| 131 | THREAD->pstate = NULL;
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| 132 | }
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