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001 /* Copyright (C) 2004 The KOS Team 002 003 This program is free software; you can redistribute it and/or 004 modify it under the terms of the GNU General Public License 005 as published by the Free Software Foundation; either version 2 006 of the License, or (at your option) any later version. 007 008 This program is distributed in the hope that it will be useful, 009 but WITHOUT ANY WARRANTY; without even the implied warranty of 010 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 011 GNU General Public License for more details. 012 013 You should have received a copy of the GNU General Public License 014 along with this program; if not, write to the Free Software 015 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 016 USA. 017 */ 018 019 #include "segment.h" 020 021 .file "irq_wrappers.S" 022 023 .text 024 025 /** The address of the table of handlers (defined in irq.c) */ 026 .extern sos_irq_handler_array 027 028 /** The address of the table of wrappers (defined below, and shared 029 with irq.c */ 030 .globl sos_irq_wrapper_array 031 032 /** The variable holding the nested level of the IRQ handlers */ 033 .extern sos_irq_nested_level_counter 034 035 /** Update the interrupted current thread's CPU context 036 Its prototype is: 037 sos_thread_prepare_irq_servicing(struct sos_cpu_state *); 038 */ 039 .extern sos_thread_prepare_irq_servicing 040 041 /** Update the kernel TSS in case we are switching to a thread in user 042 mode in order to come back into the correct kernel stack */ 043 .extern sos_cpu_context_update_kernel_tss 044 045 /** Select a thread to set on CPU (this enables user-threads 046 preemption) and configure the MMU to match that of the destination 047 thread. 048 Its prototype is: 049 struct sos_cpu_state * // Selected CPU context 050 sos_thread_prepare_irq_switch_back(); 051 */ 052 .extern sos_thread_prepare_irq_switch_back 053 054 /* These pre-handlers are for IRQ (Master PIC) */ 055 .irp id, 0,1,2,3,4,5,6,7 056 057 .p2align 2, 0x90 058 059 sos_irq_wrapper_\id: 060 .type sos_irq_wrapper_\id,@function 061 062 /* 063 * Backup the CPU context 064 */ 065 066 /* Fake error code */ 067 pushl $0 068 069 /* Backup the actual context */ 070 pushl %ebp 071 movl %esp, %ebp 072 073 pushl %edi 074 pushl %esi 075 pushl %edx 076 pushl %ecx 077 pushl %ebx 078 pushl %eax 079 subl $2,%esp 080 pushw %ss 081 pushw %ds 082 pushw %es 083 pushw %fs 084 pushw %gs 085 086 /* Set correct kernel segment descriptors' value */ 087 movw $SOS_BUILD_SEGMENT_REG_VALUE(0, 0, SOS_SEG_KDATA), %di 088 pushw %di ; popw %ds 089 pushw %di ; popw %es 090 pushw %di ; popw %fs 091 pushw %di ; popw %gs 092 093 /* 094 * Increment IRQ nested level 095 */ 096 incl sos_irq_nested_level_counter 097 /* Outermost IRQ only: store the interrupted context 098 of the current thread */ 099 cmpl $1, sos_irq_nested_level_counter 100 jne 1f 101 pushl %esp 102 call sos_thread_prepare_irq_servicing 103 addl $4, %esp 104 105 1: 106 107 /* Send EOI to PIC. See Intel 8259 datasheet 108 available on Kos website */ 109 movb $0x20, %al 110 outb %al, $0x20 111 112 /* 113 * Call the handler with IRQ number as argument 114 */ 115 pushl $\id 116 leal sos_irq_handler_array,%edi 117 call *\id*4(%edi) 118 addl $4, %esp 119 120 /* 121 * Decrement IRQ nested level 122 */ 123 cli /* Just in case we messed up everything in the handler */ 124 subl $1, sos_irq_nested_level_counter 125 126 /* sos_irq_nested_level_counter went below 0 ?! */ 127 jnc 2f 128 129 1: /* Yes: Print fatal error message */ 130 pushl $msg_nested_level_overflow 131 call sos_display_fatal_error 132 addl $4, %esp ; jmp 1b 133 /* Never returns */ 134 135 2: /* No: all right ! */ 136 137 /* Was this the outermost IRQ handler ? */ 138 jnz 3f 139 140 /* Yes: reschedule */ 141 call sos_thread_prepare_irq_switch_back 142 /* Establish new context: context switch ! */ 143 movl %eax, %esp 144 145 /* Prepare kernel TSS in case we are switching to a 146 user thread: we make sure that we will come back 147 into the kernel at a correct stack location */ 148 pushl %esp /* Pass the location of the context we are 149 restoring to the function */ 150 call sos_cpu_context_update_kernel_tss 151 addl $4, %esp 152 3: 153 /* Restore the context */ 154 popw %gs 155 popw %fs 156 popw %es 157 popw %ds 158 popw %ss 159 addl $2,%esp 160 popl %eax 161 popl %ebx 162 popl %ecx 163 popl %edx 164 popl %esi 165 popl %edi 166 popl %ebp 167 168 /* Remove fake error code */ 169 addl $4, %esp 170 171 iret 172 .endr 173 174 175 /* These pre-handlers are for IRQ (Slave PIC) */ 176 .irp id, 8,9,10,11,12,13,14,15 177 178 .p2align 2, 0x90 179 180 sos_irq_wrapper_\id: 181 .type sos_irq_wrapper_\id,@function 182 183 /* 184 * Backup the CPU context 185 */ 186 187 /* Fake error code */ 188 pushl $0 189 190 /* Backup the actual context */ 191 pushl %ebp 192 movl %esp, %ebp 193 194 pushl %edi 195 pushl %esi 196 pushl %edx 197 pushl %ecx 198 pushl %ebx 199 pushl %eax 200 subl $2,%esp 201 pushw %ss 202 pushw %ds 203 pushw %es 204 pushw %fs 205 pushw %gs 206 207 /* Set correct kernel segment descriptors' value */ 208 movw $SOS_BUILD_SEGMENT_REG_VALUE(0, 0, SOS_SEG_KDATA), %di 209 pushw %di ; popw %ds 210 pushw %di ; popw %es 211 pushw %di ; popw %fs 212 pushw %di ; popw %gs 213 214 /* 215 * Increment IRQ nested level 216 */ 217 incl sos_irq_nested_level_counter 218 /* Outermost IRQ only: store the interrupted context 219 of the current thread */ 220 cmpl $1, sos_irq_nested_level_counter 221 jne 1f 222 pushl %esp 223 call sos_thread_prepare_irq_servicing 224 addl $4, %esp 225 226 1: 227 228 /* Send EOI to PIC. See Intel 8259 datasheet 229 available on Kos website */ 230 movb $0x20, %al 231 outb %al, $0xa0 232 outb %al, $0x20 233 234 /* 235 * Call the handler with IRQ number as argument 236 */ 237 pushl $\id 238 leal sos_irq_handler_array,%edi 239 call *\id*4(%edi) 240 addl $4, %esp 241 242 /* 243 * Decrement IRQ nested level 244 */ 245 cli /* Just in case we messed up everything in the handler */ 246 subl $1, sos_irq_nested_level_counter 247 248 /* sos_irq_nested_level_counter went below 0 ?! */ 249 jnc 2f 250 251 1: /* Yes: Print fatal error message */ 252 pushl $msg_nested_level_overflow 253 call sos_display_fatal_error 254 addl $4, %esp ; jmp 1b 255 /* Never returns */ 256 257 2: /* No: all right ! */ 258 259 /* Was this the outermost IRQ handler ? */ 260 jnz 3f 261 262 /* Yes: reschedule */ 263 call sos_thread_prepare_irq_switch_back 264 /* Establish new context: context switch ! */ 265 movl %eax, %esp 266 267 /* Prepare kernel TSS in case we are switching to a 268 user thread: we make sure that we will come back 269 into the kernel at a correct stack location */ 270 pushl %esp /* Pass the location of the context we are 271 restoring to the function */ 272 call sos_cpu_context_update_kernel_tss 273 addl $4, %esp 274 3: 275 /* Restore the context */ 276 popw %gs 277 popw %fs 278 popw %es 279 popw %ds 280 popw %ss 281 addl $2,%esp 282 popl %eax 283 popl %ebx 284 popl %ecx 285 popl %edx 286 popl %esi 287 popl %edi 288 popl %ebp 289 290 /* Remove fake error code */ 291 addl $4, %esp 292 293 iret 294 .endr 295 296 .section ".rodata" 297 msg_nested_level_overflow: 298 .string "irq_wrappers.S: IRQ Nested level overflow ! System halted." 299 300 /* Build the sos_irq_wrapper_array, shared with irq.c */ 301 .p2align 5, 0x0 302 sos_irq_wrapper_array: 303 .irp id, 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 304 .long (sos_irq_wrapper_\id) 305 .endr
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