[16] | 1 | /* |
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| 2 | * hal_exception.c - implementation of exception handler for TSAR-MIPS32. |
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| 3 | * |
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| 4 | * Author Alain Greiner (2016, 2017) |
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| 5 | * |
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| 6 | * Copyright (c) UPMC Sorbonne Universites |
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| 7 | * |
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| 8 | * This file is part of ALMOS-MKH. |
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| 9 | * |
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| 10 | * ALMOS-MKH is free software; you can redistribute it and/or modify it |
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| 11 | * under the terms of the GNU General Public License as published by |
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| 12 | * the Free Software Foundation; version 2.0 of the License. |
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| 13 | * |
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| 14 | * ALMOS-MKH is distributed in the hope that it will be useful, but |
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| 15 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 17 | * General Public License for more details. |
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| 18 | * |
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| 19 | * You should have received a copy of the GNU General Public License |
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| 20 | * along with ALMOS-MKH; if not, write to the Free Software Foundation, |
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| 21 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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| 22 | */ |
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| 23 | |
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| 24 | #include <hal_types.h> |
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| 25 | #include <hal_irqmask.h> |
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| 26 | #include <hal_exception.h> |
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| 27 | #include <thread.h> |
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| 28 | #include <printk.h> |
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[380] | 29 | #include <chdev.h> |
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[16] | 30 | #include <vmm.h> |
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| 31 | #include <errno.h> |
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| 32 | #include <scheduler.h> |
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| 33 | #include <core.h> |
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| 34 | #include <signal.h> |
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| 35 | #include <syscalls.h> |
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| 36 | #include <remote_spinlock.h> |
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| 37 | #include <mips32_uzone.h> |
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| 38 | |
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[380] | 39 | |
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[16] | 40 | ////////////////////////////////////////////////////////////////////////////////////////// |
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| 41 | // Extern global variables |
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| 42 | ////////////////////////////////////////////////////////////////////////////////////////// |
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| 43 | |
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[380] | 44 | extern chdev_directory_t chdev_dir; // allocated in the kernel_init.c file. |
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[16] | 45 | |
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| 46 | ////////////////////////////////////////////////////////////////////////////////////////// |
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[381] | 47 | // This enum defines the global exception types after analysis by the exception handler. |
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| 48 | ////////////////////////////////////////////////////////////////////////////////////////// |
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| 49 | |
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| 50 | typedef enum |
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| 51 | { |
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| 52 | EXCP_NON_FATAL, |
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| 53 | EXCP_USER_ERROR, |
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| 54 | EXCP_KERNEL_PANIC, |
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| 55 | } |
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| 56 | exception_handling_type_t; |
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| 57 | |
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| 58 | ////////////////////////////////////////////////////////////////////////////////////////// |
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| 59 | // This enum defines the relevant subtypes for a MMU exception reported by the mips32. |
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| 60 | ////////////////////////////////////////////////////////////////////////////////////////// |
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| 61 | |
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| 62 | typedef enum |
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| 63 | { |
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| 64 | MMU_EXCP_PAGE_UNMAPPED, |
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| 65 | MMU_EXCP_USER_PRIVILEGE, |
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| 66 | MMU_EXCP_USER_EXEC, |
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| 67 | MMU_EXCP_USER_WRITE, |
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| 68 | } |
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| 69 | mmu_exception_subtype_t; |
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| 70 | |
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| 71 | ////////////////////////////////////////////////////////////////////////////////////////// |
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[16] | 72 | // This enum defines the relevant values for XCODE field in mips32 CP0_CR register. |
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| 73 | ////////////////////////////////////////////////////////////////////////////////////////// |
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| 74 | |
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| 75 | typedef enum |
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| 76 | { |
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[296] | 77 | XCODE_ADEL = 0x4, // Illegal address for data load |
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| 78 | XCODE_ADES = 0x5, // Illegal address for data store |
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| 79 | XCODE_IBE = 0x6, // Instruction MMU exception (can be NON-FATAL) |
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| 80 | XCODE_DBE = 0x7, // Data MMU exception (can be NON-FATAL) |
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| 81 | XCODE_RI = 0xA, // Reserved instruction exception |
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| 82 | XCODE_CPU = 0xB, // Coprocessor unusable exception (can be NON-FATAl) |
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| 83 | XCODE_OVR = 0xC, // Arithmetic Overflow exception |
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[16] | 84 | } |
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| 85 | xcode_values_t; |
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| 86 | |
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[380] | 87 | ////////////////////////////////////////////////////////////////////////////////////////// |
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| 88 | // This static function is called when a FPU Coprocessor Unavailable exception has been |
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| 89 | // detected for the calling thread. |
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| 90 | // It enables the FPU, It saves the current FPU context in the current owner thread |
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| 91 | // descriptor if required, and restore the FPU context from the calling thread descriptor. |
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| 92 | ////////////////////////////////////////////////////////////////////////////////////////// |
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| 93 | // @ this : pointer on faulty thread descriptor. |
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| 94 | // @ return always EXCP_NON_FATAL |
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| 95 | ////////////////////////////////////////////////////////////////////////////////////////// |
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| 96 | static error_t hal_fpu_exception( thread_t * this ) |
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| 97 | { |
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| 98 | core_t * core = this->core; |
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| 99 | |
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| 100 | // enable FPU |
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| 101 | hal_fpu_enable(); |
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| 102 | |
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| 103 | // save FPU context in current owner thread if required |
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| 104 | if( core->fpu_owner != NULL ) |
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| 105 | { |
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| 106 | if( core->fpu_owner != this ) |
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| 107 | { |
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| 108 | hal_fpu_context_save ( core->fpu_owner->fpu_context ); |
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| 109 | } |
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| 110 | } |
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| 111 | |
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| 112 | // attach the FPU to the requesting thread |
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| 113 | hal_fpu_context_restore( this->fpu_context ); |
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| 114 | core->fpu_owner = this; |
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| 115 | |
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| 116 | return EXCP_NON_FATAL; |
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| 117 | |
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| 118 | } // end hal_fpu_exception() |
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| 119 | |
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| 120 | ////////////////////////////////////////////////////////////////////////////////////////// |
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| 121 | // This static function is called when an MMU exception has been detected. |
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| 122 | // It get the relevant exception arguments from the MMU. |
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| 123 | // It signal a fatal error in case of illegal access. In case of page unmapped |
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| 124 | // it checks that the faulty address belongs to a registered vseg. It update the local |
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| 125 | // vseg list from the reference cluster if required, and signal a fatal user error |
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| 126 | // in case of illegal virtual address. Finally, it updates the local page table from the |
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| 127 | // reference cluster. |
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| 128 | ////////////////////////////////////////////////////////////////////////////////////////// |
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| 129 | // @ this : pointer on faulty thread descriptor. |
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| 130 | // @ return EXCP_NON_FATAL / EXCP_USER_ERROR / EXCP_KERNEL_PANIC |
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| 131 | ////////////////////////////////////////////////////////////////////////////////////////// |
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| 132 | static error_t hal_mmu_exception( thread_t * this ) |
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| 133 | { |
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| 134 | process_t * process; // local process descriptor |
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| 135 | error_t error; // return value |
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| 136 | |
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| 137 | reg_t mmu_ins_excp_code; |
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| 138 | reg_t mmu_ins_bad_vaddr; |
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| 139 | reg_t mmu_dat_excp_code; |
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| 140 | reg_t mmu_dat_bad_vaddr; |
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| 141 | |
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| 142 | intptr_t bad_vaddr; |
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| 143 | uint32_t excp_code; |
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| 144 | |
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| 145 | process = this->process; |
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| 146 | |
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| 147 | // get relevant values from MMU |
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| 148 | hal_get_mmu_excp( &mmu_ins_excp_code, |
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| 149 | &mmu_ins_bad_vaddr, |
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| 150 | &mmu_dat_excp_code, |
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| 151 | &mmu_dat_bad_vaddr ); |
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| 152 | |
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| 153 | // get exception code and faulty vaddr |
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| 154 | if( mmu_ins_excp_code ) |
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| 155 | { |
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| 156 | excp_code = mmu_ins_excp_code; |
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| 157 | bad_vaddr = mmu_ins_bad_vaddr; |
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| 158 | } |
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| 159 | else if( mmu_dat_excp_code ) |
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| 160 | { |
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| 161 | excp_code = mmu_dat_excp_code; |
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| 162 | bad_vaddr = mmu_dat_bad_vaddr; |
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| 163 | } |
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| 164 | else |
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| 165 | { |
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| 166 | return EXCP_NON_FATAL; |
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| 167 | } |
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| 168 | |
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| 169 | vmm_dmsg("\n[INFO] %s : enters for thread %x / process %x" |
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| 170 | " / bad_vaddr = %x / excep_code = %x\n", |
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| 171 | __FUNCTION__, this->trdid , process->pid , bad_vaddr , excp_code ); |
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| 172 | |
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[391] | 173 | // on TSAR, a kernel thread should not rise an MMU exception |
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| 174 | assert( (this->type != THREAD_USER) , __FUNCTION__ , |
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| 175 | "thread %x is a kernel thread / vaddr = %x\n", this->trdid , bad_vaddr ); |
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[380] | 176 | |
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| 177 | // analyse exception code |
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| 178 | if( excp_code & MMU_EXCP_PAGE_UNMAPPED ) |
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| 179 | { |
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[391] | 180 | // enable IRQs before handling page fault |
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| 181 | hal_enable_irq( NULL ); |
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| 182 | |
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[380] | 183 | // try to map the unmapped PTE |
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| 184 | error = vmm_handle_page_fault( process, |
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| 185 | bad_vaddr >> CONFIG_PPM_PAGE_SHIFT ); // vpn |
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[391] | 186 | // disable IRQs |
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| 187 | hal_disable_irq( NULL ); |
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[380] | 188 | |
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[391] | 189 | if( error ) // not enough memory |
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[380] | 190 | { |
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[391] | 191 | printk("\n[ERROR] in %s for thread %x : cannot map legal vaddr = %x\n", |
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[380] | 192 | __FUNCTION__ , this->trdid , bad_vaddr ); |
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| 193 | |
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[391] | 194 | return EXCP_USER_ERROR; |
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| 195 | } |
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| 196 | else // page fault successfully handled |
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[380] | 197 | { |
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| 198 | vmm_dmsg("\n[INFO] %s : page fault handled for vaddr = %x in thread %x\n", |
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| 199 | __FUNCTION__ , bad_vaddr , this->trdid ); |
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| 200 | |
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| 201 | return EXCP_NON_FATAL; |
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| 202 | } |
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| 203 | } |
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| 204 | else if( excp_code & MMU_EXCP_USER_PRIVILEGE ) |
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| 205 | { |
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| 206 | printk("\n[ERROR] in %s for thread %x : user access to kernel vseg at vaddr = %x\n", |
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| 207 | __FUNCTION__ , this->trdid , bad_vaddr ); |
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| 208 | |
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| 209 | return EXCP_USER_ERROR; |
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| 210 | } |
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| 211 | else if( excp_code & MMU_EXCP_USER_EXEC ) |
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| 212 | { |
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| 213 | printk("\n[ERROR] in %s for thread %x : access to non-exec vseg at vaddr = %x\n", |
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| 214 | __FUNCTION__ , this->trdid , bad_vaddr ); |
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| 215 | |
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| 216 | return EXCP_USER_ERROR; |
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| 217 | } |
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| 218 | else if( excp_code & MMU_EXCP_USER_WRITE ) |
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| 219 | { |
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| 220 | printk("\n[ERROR] in %s for thread %x : write to non-writable vseg at vaddr = %x\n", |
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| 221 | __FUNCTION__ , this->trdid , bad_vaddr ); |
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| 222 | |
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| 223 | return EXCP_USER_ERROR; |
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| 224 | } |
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| 225 | |
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| 226 | else // this is a kernel error => panic |
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| 227 | { |
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| 228 | printk("\n[PANIC] in %s for thread %x : kernel exception = %x / vaddr = %x\n", |
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| 229 | __FUNCTION__ , this->trdid , excp_code , bad_vaddr ); |
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| 230 | |
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| 231 | return EXCP_KERNEL_PANIC; |
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| 232 | } |
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| 233 | |
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| 234 | } // end hal_mmu_exception() |
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| 235 | |
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| 236 | ////////////////////////////////////////////////////////////////////////////////////////// |
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| 237 | // This static function prints on the kernel terminal the saved context (core registers) |
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| 238 | // and the thread state of a faulty thread. |
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| 239 | ////////////////////////////////////////////////////////////////////////////////////////// |
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| 240 | // @ this : pointer on faulty thread descriptor. |
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| 241 | // @ regs_tbl : pointer on register array. |
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| 242 | // @ return always EXCP_NON_FATAL |
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| 243 | ////////////////////////////////////////////////////////////////////////////////////////// |
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| 244 | static void hal_exception_dump( thread_t * this, |
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| 245 | reg_t * regs_tbl ) |
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| 246 | { |
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| 247 | uint32_t save_sr; |
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| 248 | |
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| 249 | // get pointers on TXT0 chdev |
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| 250 | xptr_t txt0_xp = chdev_dir.txt[0]; |
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| 251 | cxy_t txt0_cxy = GET_CXY( txt0_xp ); |
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| 252 | chdev_t * txt0_ptr = GET_PTR( txt0_xp ); |
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| 253 | |
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| 254 | // get extended pointer on remote TXT0 chdev lock |
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| 255 | xptr_t lock_xp = XPTR( txt0_cxy , &txt0_ptr->wait_lock ); |
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| 256 | |
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| 257 | // get TXT0 lock in busy waiting mode |
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| 258 | remote_spinlock_lock_busy( lock_xp , &save_sr ); |
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| 259 | |
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| 260 | if( this->type == THREAD_USER ) |
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| 261 | nolock_printk("\n================= USER ERROR / cycle %d ====================\n", |
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| 262 | hal_time_stamp() ); |
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| 263 | else |
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| 264 | nolock_printk("\n================= KERNEL PANIC / cycle %d ==================\n", |
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| 265 | hal_time_stamp() ); |
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| 266 | |
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| 267 | nolock_printk(" thread type = %s / trdid = %x / pid %x / core[%x,%d]\n" |
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| 268 | " local locks = %d / remote locks = %d / blocked_vector = %X\n\n", |
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| 269 | thread_type_str(this->type), this->trdid, this->process->pid, local_cxy, |
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| 270 | this->core->lid, this->local_locks, this->remote_locks, this->blocked ); |
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| 271 | |
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| 272 | nolock_printk("CR %X EPC %X SR %X SP %X\n", |
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| 273 | regs_tbl[UZ_CR], regs_tbl[UZ_EPC], regs_tbl[UZ_SR], regs_tbl[UZ_SP]); |
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| 274 | |
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| 275 | nolock_printk("at_1 %X v0_2 %X v1_3 %X a0_4 %X a1_5 %X\n", |
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| 276 | regs_tbl[UZ_AT], regs_tbl[UZ_V0], regs_tbl[UZ_V1], regs_tbl[UZ_A0], regs_tbl[UZ_A1]); |
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| 277 | |
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| 278 | nolock_printk("a2_6 %X a3_7 %X t0_8 %X t1_9 %X t2_10 %X\n", |
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| 279 | regs_tbl[UZ_A2],regs_tbl[UZ_A3],regs_tbl[UZ_T0],regs_tbl[UZ_T1],regs_tbl[UZ_T2]); |
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| 280 | |
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| 281 | nolock_printk("t3_11 %X t4_12 %X t5_13 %X t6_14 %X t7_15 %X\n", |
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| 282 | regs_tbl[UZ_T3],regs_tbl[UZ_T4],regs_tbl[UZ_T5],regs_tbl[UZ_T6],regs_tbl[UZ_T7]); |
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| 283 | |
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| 284 | nolock_printk("t8_24 %X t9_25 %X gp_28 %X c0_hi %X c0_lo %X\n", |
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| 285 | regs_tbl[UZ_T8],regs_tbl[UZ_T9],regs_tbl[UZ_GP],regs_tbl[UZ_HI],regs_tbl[UZ_LO]); |
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| 286 | |
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| 287 | nolock_printk("s0_16 %X s1_17 %X s2_18 %X s3_19 %X s4_20 %X\n", |
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| 288 | regs_tbl[UZ_S0],regs_tbl[UZ_S1],regs_tbl[UZ_S2],regs_tbl[UZ_S3],regs_tbl[UZ_S4]); |
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| 289 | |
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| 290 | nolock_printk("s5_21 %X s6_22 %X s7_23 %X s8_30 %X ra_31 %X\n", |
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| 291 | regs_tbl[UZ_S5],regs_tbl[UZ_S6],regs_tbl[UZ_S7],regs_tbl[UZ_S8],regs_tbl[UZ_RA]); |
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| 292 | |
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| 293 | // release the lock |
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| 294 | remote_spinlock_unlock_busy( lock_xp , save_sr ); |
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| 295 | |
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| 296 | } // end hal_exception_dump() |
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| 297 | |
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| 298 | |
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| 299 | /////////////////////////////////////////////////////////////////////////////// |
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| 300 | // TODO replace the hal_core_sleep() by the generic panic() function. |
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| 301 | /////////////////////////////////////////////////////////////////////////////// |
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[16] | 302 | void hal_do_exception( thread_t * this, |
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| 303 | reg_t * regs_tbl ) |
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| 304 | { |
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| 305 | error_t error; |
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| 306 | uint32_t excCode; // 4 bits XCODE from CP0_CR |
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| 307 | |
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| 308 | // get 4 bits XCODE from CP0_CR register |
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| 309 | excCode = (regs_tbl[UZ_CR] >> 2) & 0xF; |
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| 310 | |
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| 311 | switch(excCode) |
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| 312 | { |
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| 313 | case XCODE_DBE: // can be non fatal |
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[380] | 314 | case XCODE_IBE: // can be non fatal |
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[16] | 315 | { |
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[380] | 316 | error = hal_mmu_exception( this ); |
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[16] | 317 | } |
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| 318 | break; |
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| 319 | |
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| 320 | case XCODE_CPU: // can be non fatal |
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| 321 | { |
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| 322 | if( ((regs_tbl[UZ_CR] >> 28) & 0x3) == 1 ) // unavailable FPU |
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| 323 | { |
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[380] | 324 | error = hal_fpu_exception( this ); |
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[16] | 325 | } |
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| 326 | else |
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| 327 | { |
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| 328 | error = EXCP_USER_ERROR; |
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| 329 | } |
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| 330 | } |
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| 331 | break; |
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| 332 | |
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[380] | 333 | case XCODE_OVR: // user fatal error |
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| 334 | case XCODE_RI: // user fatal error |
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| 335 | case XCODE_ADEL: // user fatal error |
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| 336 | case XCODE_ADES: // user fatal error |
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[16] | 337 | { |
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| 338 | error = EXCP_USER_ERROR; |
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| 339 | } |
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| 340 | break; |
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| 341 | |
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| 342 | default: |
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| 343 | { |
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[317] | 344 | error = EXCP_KERNEL_PANIC; |
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[16] | 345 | } |
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| 346 | } |
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| 347 | |
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| 348 | // analyse error code |
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[317] | 349 | if( error == EXCP_USER_ERROR ) // user error => kill user process |
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[16] | 350 | { |
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| 351 | hal_exception_dump( this , regs_tbl ); |
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| 352 | sys_kill( this->process->pid , SIGKILL ); |
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| 353 | } |
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| 354 | else if( error == EXCP_KERNEL_PANIC ) // kernel error => kernel panic |
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| 355 | { |
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| 356 | hal_exception_dump( this , regs_tbl ); |
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| 357 | hal_core_sleep(); |
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| 358 | } |
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| 359 | } // end hal_do_exception() |
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| 360 | |
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| 361 | |
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