cpuswitch.S revision 1.1.2.4
1 1.1.2.4 jdolecek /* $NetBSD: cpuswitch.S,v 1.1.2.4 2002/02/11 20:07:18 jdolecek Exp $ */ 2 1.1.2.2 lukem 3 1.1.2.2 lukem /* 4 1.1.2.2 lukem * Copyright (c) 1994-1998 Mark Brinicombe. 5 1.1.2.2 lukem * Copyright (c) 1994 Brini. 6 1.1.2.2 lukem * All rights reserved. 7 1.1.2.2 lukem * 8 1.1.2.2 lukem * This code is derived from software written for Brini by Mark Brinicombe 9 1.1.2.2 lukem * 10 1.1.2.2 lukem * Redistribution and use in source and binary forms, with or without 11 1.1.2.2 lukem * modification, are permitted provided that the following conditions 12 1.1.2.2 lukem * are met: 13 1.1.2.2 lukem * 1. Redistributions of source code must retain the above copyright 14 1.1.2.2 lukem * notice, this list of conditions and the following disclaimer. 15 1.1.2.2 lukem * 2. Redistributions in binary form must reproduce the above copyright 16 1.1.2.2 lukem * notice, this list of conditions and the following disclaimer in the 17 1.1.2.2 lukem * documentation and/or other materials provided with the distribution. 18 1.1.2.2 lukem * 3. All advertising materials mentioning features or use of this software 19 1.1.2.2 lukem * must display the following acknowledgement: 20 1.1.2.2 lukem * This product includes software developed by Brini. 21 1.1.2.2 lukem * 4. The name of the company nor the name of the author may be used to 22 1.1.2.2 lukem * endorse or promote products derived from this software without specific 23 1.1.2.2 lukem * prior written permission. 24 1.1.2.2 lukem * 25 1.1.2.2 lukem * THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED 26 1.1.2.2 lukem * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 27 1.1.2.2 lukem * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 28 1.1.2.2 lukem * IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 29 1.1.2.2 lukem * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 30 1.1.2.2 lukem * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 31 1.1.2.2 lukem * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 1.1.2.2 lukem * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 1.1.2.2 lukem * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 1.1.2.2 lukem * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 1.1.2.2 lukem * SUCH DAMAGE. 36 1.1.2.2 lukem * 37 1.1.2.2 lukem * RiscBSD kernel project 38 1.1.2.2 lukem * 39 1.1.2.2 lukem * cpuswitch.S 40 1.1.2.2 lukem * 41 1.1.2.2 lukem * cpu switching functions 42 1.1.2.2 lukem * 43 1.1.2.2 lukem * Created : 15/10/94 44 1.1.2.2 lukem */ 45 1.1.2.2 lukem 46 1.1.2.2 lukem #include "opt_armfpe.h" 47 1.1.2.2 lukem 48 1.1.2.2 lukem #include "assym.h" 49 1.1.2.2 lukem #include <machine/param.h> 50 1.1.2.2 lukem #include <machine/cpu.h> 51 1.1.2.2 lukem #include <machine/frame.h> 52 1.1.2.2 lukem #include <machine/asm.h> 53 1.1.2.2 lukem 54 1.1.2.2 lukem #undef IRQdisable 55 1.1.2.2 lukem #undef IRQenable 56 1.1.2.2 lukem 57 1.1.2.2 lukem /* 58 1.1.2.2 lukem * New experimental definitions of IRQdisable and IRQenable 59 1.1.2.2 lukem * These keep FIQ's enabled since FIQ's are special. 60 1.1.2.2 lukem */ 61 1.1.2.2 lukem 62 1.1.2.2 lukem #define IRQdisable \ 63 1.1.2.2 lukem mrs r14, cpsr_all ; \ 64 1.1.2.2 lukem orr r14, r14, #(I32_bit) ; \ 65 1.1.2.2 lukem msr cpsr_all, r14 ; \ 66 1.1.2.2 lukem 67 1.1.2.2 lukem #define IRQenable \ 68 1.1.2.2 lukem mrs r14, cpsr_all ; \ 69 1.1.2.2 lukem bic r14, r14, #(I32_bit) ; \ 70 1.1.2.2 lukem msr cpsr_all, r14 ; \ 71 1.1.2.2 lukem 72 1.1.2.2 lukem /* 73 1.1.2.2 lukem * setrunqueue() and remrunqueue() 74 1.1.2.2 lukem * 75 1.1.2.2 lukem * Functions to add and remove a process for the run queue. 76 1.1.2.2 lukem */ 77 1.1.2.2 lukem 78 1.1.2.2 lukem .text 79 1.1.2.2 lukem 80 1.1.2.2 lukem Lwhichqs: 81 1.1.2.2 lukem .word _C_LABEL(sched_whichqs) 82 1.1.2.2 lukem 83 1.1.2.2 lukem Lqs: 84 1.1.2.2 lukem .word _C_LABEL(sched_qs) 85 1.1.2.2 lukem 86 1.1.2.2 lukem /* 87 1.1.2.2 lukem * On entry 88 1.1.2.2 lukem * r0 = process 89 1.1.2.2 lukem */ 90 1.1.2.2 lukem 91 1.1.2.2 lukem ENTRY(setrunqueue) 92 1.1.2.2 lukem /* 93 1.1.2.2 lukem * Local register usage 94 1.1.2.2 lukem * r0 = process 95 1.1.2.2 lukem * r1 = queue 96 1.1.2.2 lukem * r2 = &qs[queue] and temp 97 1.1.2.2 lukem * r3 = temp 98 1.1.2.2 lukem * r12 = whichqs 99 1.1.2.2 lukem */ 100 1.1.2.2 lukem #ifdef DIAGNOSTIC 101 1.1.2.2 lukem ldr r1, [r0, #(P_BACK)] 102 1.1.2.2 lukem teq r1, #0x00000000 103 1.1.2.2 lukem bne Lsetrunqueue_erg 104 1.1.2.2 lukem 105 1.1.2.2 lukem ldr r1, [r0, #(P_WCHAN)] 106 1.1.2.2 lukem teq r1, #0x00000000 107 1.1.2.2 lukem bne Lsetrunqueue_erg 108 1.1.2.2 lukem #endif 109 1.1.2.2 lukem 110 1.1.2.2 lukem /* Get the priority of the queue */ 111 1.1.2.2 lukem ldrb r1, [r0, #(P_PRIORITY)] 112 1.1.2.2 lukem mov r1, r1, lsr #2 113 1.1.2.2 lukem 114 1.1.2.2 lukem /* Indicate that there is a process on this queue */ 115 1.1.2.2 lukem ldr r12, Lwhichqs 116 1.1.2.2 lukem ldr r2, [r12] 117 1.1.2.2 lukem mov r3, #0x00000001 118 1.1.2.2 lukem mov r3, r3, lsl r1 119 1.1.2.2 lukem orr r2, r2, r3 120 1.1.2.2 lukem str r2, [r12] 121 1.1.2.2 lukem 122 1.1.2.2 lukem /* Get the address of the queue */ 123 1.1.2.2 lukem ldr r2, Lqs 124 1.1.2.2 lukem add r1, r2, r1, lsl # 3 125 1.1.2.2 lukem 126 1.1.2.2 lukem /* Hook the process in */ 127 1.1.2.2 lukem str r1, [r0, #(P_FORW)] 128 1.1.2.2 lukem ldr r2, [r1, #(P_BACK)] 129 1.1.2.2 lukem 130 1.1.2.2 lukem str r0, [r1, #(P_BACK)] 131 1.1.2.2 lukem #ifdef DIAGNOSTIC 132 1.1.2.2 lukem teq r2, #0x00000000 133 1.1.2.2 lukem beq Lsetrunqueue_erg 134 1.1.2.2 lukem #endif 135 1.1.2.2 lukem str r0, [r2, #(P_FORW)] 136 1.1.2.2 lukem str r2, [r0, #(P_BACK)] 137 1.1.2.2 lukem 138 1.1.2.2 lukem mov pc, lr 139 1.1.2.2 lukem 140 1.1.2.2 lukem #ifdef DIAGNOSTIC 141 1.1.2.2 lukem Lsetrunqueue_erg: 142 1.1.2.2 lukem mov r2, r1 143 1.1.2.2 lukem mov r1, r0 144 1.1.2.2 lukem add r0, pc, #Ltext1 - . - 8 145 1.1.2.2 lukem bl _C_LABEL(printf) 146 1.1.2.2 lukem 147 1.1.2.2 lukem ldr r2, Lqs 148 1.1.2.2 lukem ldr r1, [r2] 149 1.1.2.2 lukem add r0, pc, #Ltext2 - . - 8 150 1.1.2.2 lukem b _C_LABEL(panic) 151 1.1.2.2 lukem 152 1.1.2.2 lukem Ltext1: 153 1.1.2.2 lukem .asciz "setrunqueue : %08x %08x\n" 154 1.1.2.2 lukem Ltext2: 155 1.1.2.2 lukem .asciz "setrunqueue : [qs]=%08x qs=%08x\n" 156 1.1.2.2 lukem .align 0 157 1.1.2.2 lukem #endif 158 1.1.2.2 lukem 159 1.1.2.2 lukem /* 160 1.1.2.2 lukem * On entry 161 1.1.2.2 lukem * r0 = process 162 1.1.2.2 lukem */ 163 1.1.2.2 lukem 164 1.1.2.2 lukem ENTRY(remrunqueue) 165 1.1.2.2 lukem /* 166 1.1.2.2 lukem * Local register usage 167 1.1.2.2 lukem * r0 = oldproc 168 1.1.2.2 lukem * r1 = queue 169 1.1.2.2 lukem * r2 = &qs[queue] and scratch 170 1.1.2.2 lukem * r3 = scratch 171 1.1.2.2 lukem * r12 = whichqs 172 1.1.2.2 lukem */ 173 1.1.2.2 lukem 174 1.1.2.2 lukem /* Get the priority of the queue */ 175 1.1.2.2 lukem ldrb r1, [r0, #(P_PRIORITY)] 176 1.1.2.2 lukem mov r1, r1, lsr #2 177 1.1.2.2 lukem 178 1.1.2.2 lukem /* Unhook the process */ 179 1.1.2.2 lukem ldr r2, [r0, #(P_FORW)] 180 1.1.2.2 lukem ldr r3, [r0, #(P_BACK)] 181 1.1.2.2 lukem 182 1.1.2.2 lukem str r3, [r2, #(P_BACK)] 183 1.1.2.2 lukem str r2, [r3, #(P_FORW)] 184 1.1.2.2 lukem 185 1.1.2.2 lukem /* If the queue is now empty clear the queue not empty flag */ 186 1.1.2.2 lukem teq r2, r3 187 1.1.2.2 lukem 188 1.1.2.2 lukem /* This could be reworked to avoid the use of r4 */ 189 1.1.2.2 lukem ldreq r12, Lwhichqs 190 1.1.2.2 lukem ldreq r2, [r12] 191 1.1.2.2 lukem moveq r3, #0x00000001 192 1.1.2.2 lukem moveq r3, r3, lsl r1 193 1.1.2.2 lukem biceq r2, r2, r3 194 1.1.2.2 lukem streq r2, [r12] 195 1.1.2.2 lukem 196 1.1.2.2 lukem /* Remove the back pointer for the process */ 197 1.1.2.2 lukem mov r1, #0x00000000 198 1.1.2.2 lukem str r1, [r0, #(P_BACK)] 199 1.1.2.2 lukem 200 1.1.2.2 lukem mov pc, lr 201 1.1.2.2 lukem 202 1.1.2.2 lukem 203 1.1.2.2 lukem /* 204 1.1.2.2 lukem * cpuswitch() 205 1.1.2.2 lukem * 206 1.1.2.2 lukem * preforms a process context switch. 207 1.1.2.2 lukem * This function has several entry points 208 1.1.2.2 lukem */ 209 1.1.2.2 lukem 210 1.1.2.2 lukem Lcurproc: 211 1.1.2.2 lukem .word _C_LABEL(curproc) 212 1.1.2.2 lukem 213 1.1.2.2 lukem Lcurpcb: 214 1.1.2.2 lukem .word _C_LABEL(curpcb) 215 1.1.2.2 lukem 216 1.1.2.2 lukem Lwant_resched: 217 1.1.2.2 lukem .word _C_LABEL(want_resched) 218 1.1.2.2 lukem 219 1.1.2.2 lukem Lcpufuncs: 220 1.1.2.2 lukem .word _C_LABEL(cpufuncs) 221 1.1.2.2 lukem 222 1.1.2.2 lukem .data 223 1.1.2.2 lukem .global _C_LABEL(curpcb) 224 1.1.2.2 lukem _C_LABEL(curpcb): 225 1.1.2.2 lukem .word 0x00000000 226 1.1.2.2 lukem .text 227 1.1.2.2 lukem 228 1.1.2.2 lukem Lblock_userspace_access: 229 1.1.2.2 lukem .word _C_LABEL(block_userspace_access) 230 1.1.2.2 lukem 231 1.1.2.2 lukem /* 232 1.1.2.2 lukem * Idle loop, exercised while waiting for a process to wake up. 233 1.1.2.2 lukem */ 234 1.1.2.3 thorpej ASENTRY_NP(idle) 235 1.1.2.2 lukem /* Enable interrupts */ 236 1.1.2.2 lukem IRQenable 237 1.1.2.2 lukem 238 1.1.2.2 lukem /* XXX - r1 needs to be preserved for cpu_switch */ 239 1.1.2.2 lukem mov r7, r1 240 1.1.2.2 lukem ldr r3, Lcpufuncs 241 1.1.2.2 lukem mov r0, #0 242 1.1.2.2 lukem add lr, pc, #Lidle_slept - . - 8 243 1.1.2.2 lukem ldr pc, [r3, #CF_SLEEP] 244 1.1.2.2 lukem 245 1.1.2.2 lukem Lidle_slept: 246 1.1.2.2 lukem mov r1, r7 247 1.1.2.2 lukem 248 1.1.2.2 lukem /* Disable interrupts while we check for an active queue */ 249 1.1.2.2 lukem IRQdisable 250 1.1.2.2 lukem ldr r7, Lwhichqs 251 1.1.2.2 lukem ldr r3, [r7] 252 1.1.2.2 lukem teq r3, #0x00000000 253 1.1.2.2 lukem bne sw1 254 1.1.2.2 lukem 255 1.1.2.2 lukem /* All processes are still asleep so idle a while longer */ 256 1.1.2.3 thorpej b _ASM_LABEL(idle) 257 1.1.2.2 lukem 258 1.1.2.2 lukem 259 1.1.2.2 lukem /* 260 1.1.2.2 lukem * Find a new process to run, save the current context and 261 1.1.2.2 lukem * load the new context 262 1.1.2.2 lukem */ 263 1.1.2.2 lukem 264 1.1.2.2 lukem ENTRY(cpu_switch) 265 1.1.2.2 lukem /* 266 1.1.2.2 lukem * Local register usage. Some of these registers are out of date. 267 1.1.2.2 lukem * r1 = oldproc 268 1.1.2.2 lukem * r2 = spl level 269 1.1.2.2 lukem * r3 = whichqs 270 1.1.2.2 lukem * r4 = queue 271 1.1.2.2 lukem * r5 = &qs[queue] 272 1.1.2.2 lukem * r6 = newproc 273 1.1.2.2 lukem * r7 = scratch 274 1.1.2.2 lukem */ 275 1.1.2.2 lukem stmfd sp!, {r4-r7, lr} 276 1.1.2.2 lukem 277 1.1.2.2 lukem /* 278 1.1.2.2 lukem * Get the current process and indicate that there is no longer 279 1.1.2.2 lukem * a valid process (curproc = 0) 280 1.1.2.2 lukem */ 281 1.1.2.2 lukem ldr r7, Lcurproc 282 1.1.2.2 lukem ldr r1, [r7] 283 1.1.2.2 lukem mov r0, #0x00000000 284 1.1.2.2 lukem str r0, [r7] 285 1.1.2.2 lukem 286 1.1.2.2 lukem /* Zero the pcb */ 287 1.1.2.2 lukem ldr r7, Lcurpcb 288 1.1.2.2 lukem str r0, [r7] 289 1.1.2.2 lukem 290 1.1.2.2 lukem /* Lower the spl level to spl0 and get the current spl level. */ 291 1.1.2.2 lukem mov r7, r1 292 1.1.2.2 lukem 293 1.1.2.3 thorpej #ifdef __NEWINTR 294 1.1.2.3 thorpej mov r0, #(IPL_NONE) 295 1.1.2.3 thorpej bl _C_LABEL(_spllower) 296 1.1.2.3 thorpej #else /* ! __NEWINTR */ 297 1.1.2.2 lukem #ifdef spl0 298 1.1.2.2 lukem mov r0, #(_SPL_0) 299 1.1.2.2 lukem bl _C_LABEL(splx) 300 1.1.2.2 lukem #else 301 1.1.2.2 lukem bl _C_LABEL(spl0) 302 1.1.2.3 thorpej #endif /* spl0 */ 303 1.1.2.3 thorpej #endif /* __NEWINTR */ 304 1.1.2.2 lukem 305 1.1.2.2 lukem /* Push the old spl level onto the stack */ 306 1.1.2.2 lukem str r0, [sp, #-0x0004]! 307 1.1.2.2 lukem 308 1.1.2.2 lukem mov r1, r7 309 1.1.2.2 lukem 310 1.1.2.2 lukem /* First phase : find a new process */ 311 1.1.2.2 lukem 312 1.1.2.2 lukem /* rem: r1 = old proc */ 313 1.1.2.2 lukem 314 1.1.2.2 lukem switch_search: 315 1.1.2.2 lukem IRQdisable 316 1.1.2.2 lukem 317 1.1.2.2 lukem /* Do we have any active queues */ 318 1.1.2.2 lukem ldr r7, Lwhichqs 319 1.1.2.2 lukem ldr r3, [r7] 320 1.1.2.2 lukem 321 1.1.2.2 lukem /* If not we must idle until we do. */ 322 1.1.2.2 lukem teq r3, #0x00000000 323 1.1.2.3 thorpej beq _ASM_LABEL(idle) 324 1.1.2.2 lukem 325 1.1.2.2 lukem sw1: 326 1.1.2.2 lukem /* rem: r1 = old proc */ 327 1.1.2.2 lukem /* rem: r3 = whichqs */ 328 1.1.2.2 lukem /* rem: interrupts are disabled */ 329 1.1.2.2 lukem 330 1.1.2.2 lukem /* 331 1.1.2.2 lukem * We have found an active queue. Currently we do not know which queue 332 1.1.2.2 lukem * is active just that one of them is. 333 1.1.2.2 lukem */ 334 1.1.2.2 lukem /* this is the ffs algorithm devised by d.seal and posted to 335 1.1.2.2 lukem * comp.sys.arm on 16 Feb 1994. 336 1.1.2.2 lukem */ 337 1.1.2.2 lukem rsb r5, r3, #0 338 1.1.2.2 lukem ands r0, r3, r5 339 1.1.2.2 lukem 340 1.1.2.2 lukem adr r5, Lcpu_switch_ffs_table 341 1.1.2.2 lukem 342 1.1.2.3 thorpej /* X = R0 */ 343 1.1.2.3 thorpej orr r4, r0, r0, lsl #4 /* r4 = X * 0x11 */ 344 1.1.2.3 thorpej orr r4, r4, r4, lsl #6 /* r4 = X * 0x451 */ 345 1.1.2.3 thorpej rsb r4, r4, r4, lsl #16 /* r4 = X * 0x0450fbaf */ 346 1.1.2.2 lukem 347 1.1.2.2 lukem /* used further down, saves SA stall */ 348 1.1.2.2 lukem ldr r6, Lqs 349 1.1.2.2 lukem 350 1.1.2.3 thorpej /* now lookup in table indexed on top 6 bits of a4 */ 351 1.1.2.2 lukem ldrb r4, [ r5, r4, lsr #26 ] 352 1.1.2.2 lukem 353 1.1.2.2 lukem /* rem: r0 = bit mask of chosen queue (1 << r4) */ 354 1.1.2.2 lukem /* rem: r1 = old proc */ 355 1.1.2.2 lukem /* rem: r3 = whichqs */ 356 1.1.2.2 lukem /* rem: r4 = queue number */ 357 1.1.2.2 lukem /* rem: interrupts are disabled */ 358 1.1.2.2 lukem 359 1.1.2.2 lukem /* Get the address of the queue (&qs[queue]) */ 360 1.1.2.2 lukem add r5, r6, r4, lsl #3 361 1.1.2.2 lukem 362 1.1.2.2 lukem /* 363 1.1.2.2 lukem * Get the process from the queue and place the next process in 364 1.1.2.2 lukem * the queue at the head. This basically unlinks the process at 365 1.1.2.2 lukem * the head of the queue. 366 1.1.2.2 lukem */ 367 1.1.2.2 lukem ldr r6, [r5, #(P_FORW)] 368 1.1.2.2 lukem 369 1.1.2.2 lukem /* rem: r6 = new process */ 370 1.1.2.2 lukem ldr r7, [r6, #(P_FORW)] 371 1.1.2.2 lukem str r7, [r5, #(P_FORW)] 372 1.1.2.2 lukem 373 1.1.2.2 lukem /* 374 1.1.2.2 lukem * Test to see if the queue is now empty. If the head of the queue 375 1.1.2.2 lukem * points to the queue itself then there are no more processes in 376 1.1.2.2 lukem * the queue. We can therefore clear the queue not empty flag held 377 1.1.2.2 lukem * in r3. 378 1.1.2.2 lukem */ 379 1.1.2.2 lukem 380 1.1.2.2 lukem teq r5, r7 381 1.1.2.2 lukem biceq r3, r3, r0 382 1.1.2.2 lukem 383 1.1.2.2 lukem /* rem: r0 = bit mask of chosen queue (1 << r4) - NOT NEEDED AN MORE */ 384 1.1.2.2 lukem 385 1.1.2.2 lukem /* Fix the back pointer for the process now at the head of the queue. */ 386 1.1.2.2 lukem ldr r0, [r6, #(P_BACK)] 387 1.1.2.2 lukem str r0, [r7, #(P_BACK)] 388 1.1.2.2 lukem 389 1.1.2.2 lukem /* Update the RAM copy of the queue not empty flags word. */ 390 1.1.2.2 lukem ldr r7, Lwhichqs 391 1.1.2.2 lukem str r3, [r7] 392 1.1.2.2 lukem 393 1.1.2.2 lukem /* rem: r1 = old proc */ 394 1.1.2.2 lukem /* rem: r3 = whichqs - NOT NEEDED ANY MORE */ 395 1.1.2.2 lukem /* rem: r4 = queue number - NOT NEEDED ANY MORE */ 396 1.1.2.2 lukem /* rem: r6 = new process */ 397 1.1.2.2 lukem /* rem: interrupts are disabled */ 398 1.1.2.2 lukem 399 1.1.2.2 lukem /* Clear the want_resched flag */ 400 1.1.2.2 lukem ldr r7, Lwant_resched 401 1.1.2.3 thorpej mov r0, #0x00000000 402 1.1.2.2 lukem str r0, [r7] 403 1.1.2.2 lukem 404 1.1.2.2 lukem /* 405 1.1.2.2 lukem * Clear the back pointer of the process we have removed from 406 1.1.2.2 lukem * the head of the queue. The new process is isolated now. 407 1.1.2.2 lukem */ 408 1.1.2.2 lukem str r0, [r6, #(P_BACK)] 409 1.1.2.2 lukem 410 1.1.2.2 lukem /* p->p_cpu initialized in fork1() for single-processor */ 411 1.1.2.2 lukem 412 1.1.2.2 lukem /* Process is now on a processor. */ 413 1.1.2.2 lukem mov r0, #SONPROC /* p->p_stat = SONPROC */ 414 1.1.2.2 lukem strb r0, [r6, #(P_STAT)] 415 1.1.2.2 lukem 416 1.1.2.2 lukem /* We have a new curproc now so make a note it */ 417 1.1.2.2 lukem ldr r7, Lcurproc 418 1.1.2.2 lukem str r6, [r7] 419 1.1.2.2 lukem 420 1.1.2.2 lukem /* Hook in a new pcb */ 421 1.1.2.2 lukem ldr r7, Lcurpcb 422 1.1.2.2 lukem ldr r0, [r6, #(P_ADDR)] 423 1.1.2.2 lukem str r0, [r7] 424 1.1.2.2 lukem 425 1.1.2.2 lukem /* At this point we can allow IRQ's again. */ 426 1.1.2.2 lukem IRQenable 427 1.1.2.2 lukem 428 1.1.2.2 lukem /* rem: r1 = old proc */ 429 1.1.2.2 lukem /* rem: r6 = new process */ 430 1.1.2.3 thorpej /* rem: interrupts are enabled */ 431 1.1.2.2 lukem 432 1.1.2.2 lukem /* 433 1.1.2.2 lukem * If the new process is the same as the process that called 434 1.1.2.2 lukem * cpu_switch() then we do not need to save and restore any 435 1.1.2.2 lukem * contexts. This means we can make a quick exit. 436 1.1.2.2 lukem * The test is simple if curproc on entry (now in r1) is the 437 1.1.2.2 lukem * same as the proc removed from the queue we can jump to the exit. 438 1.1.2.2 lukem */ 439 1.1.2.2 lukem teq r1, r6 440 1.1.2.2 lukem beq switch_return 441 1.1.2.2 lukem 442 1.1.2.2 lukem /* 443 1.1.2.2 lukem * If the curproc on entry to cpu_switch was zero then the 444 1.1.2.2 lukem * process that called it was exiting. This means that we do 445 1.1.2.2 lukem * not need to save the current context. Instead we can jump 446 1.1.2.2 lukem * straight to restoring the context for the new process. 447 1.1.2.2 lukem */ 448 1.1.2.2 lukem teq r1, #0x00000000 449 1.1.2.2 lukem beq switch_exited 450 1.1.2.2 lukem 451 1.1.2.2 lukem /* rem: r1 = old proc */ 452 1.1.2.2 lukem /* rem: r6 = new process */ 453 1.1.2.3 thorpej /* rem: interrupts are enabled */ 454 1.1.2.2 lukem 455 1.1.2.2 lukem /* Stage two : Save old context */ 456 1.1.2.2 lukem 457 1.1.2.2 lukem /* Remember the old process in r0 */ 458 1.1.2.2 lukem mov r0, r1 459 1.1.2.2 lukem 460 1.1.2.2 lukem /* Get the user structure for the old process. */ 461 1.1.2.2 lukem ldr r1, [r1, #(P_ADDR)] 462 1.1.2.2 lukem 463 1.1.2.2 lukem /* Save all the registers in the old process's pcb */ 464 1.1.2.2 lukem add r7, r1, #(PCB_R8) 465 1.1.2.2 lukem stmia r7, {r8-r13} 466 1.1.2.2 lukem 467 1.1.2.2 lukem /* 468 1.1.2.2 lukem * This can be optimised... We know we want to go from SVC32 469 1.1.2.2 lukem * mode to UND32 mode 470 1.1.2.2 lukem */ 471 1.1.2.2 lukem mrs r3, cpsr_all 472 1.1.2.2 lukem bic r2, r3, #(PSR_MODE) 473 1.1.2.2 lukem orr r2, r2, #(PSR_UND32_MODE | I32_bit) 474 1.1.2.2 lukem msr cpsr_all, r2 475 1.1.2.2 lukem 476 1.1.2.2 lukem str sp, [r1, #(PCB_UND_SP)] 477 1.1.2.2 lukem 478 1.1.2.2 lukem msr cpsr_all, r3 /* Restore the old mode */ 479 1.1.2.2 lukem 480 1.1.2.2 lukem /* rem: r0 = old proc */ 481 1.1.2.3 thorpej /* rem: r1 = old pcb */ 482 1.1.2.2 lukem /* rem: r6 = new process */ 483 1.1.2.3 thorpej /* rem: interrupts are enabled */ 484 1.1.2.2 lukem 485 1.1.2.2 lukem /* What else needs to be saved Only FPA stuff when that is supported */ 486 1.1.2.2 lukem 487 1.1.2.2 lukem /* Third phase : restore saved context */ 488 1.1.2.2 lukem 489 1.1.2.2 lukem switch_exited: 490 1.1.2.2 lukem /* Don't allow user space access beween the purge and the switch */ 491 1.1.2.2 lukem ldr r3, Lblock_userspace_access 492 1.1.2.2 lukem ldr r2, [r3] 493 1.1.2.2 lukem orr r0, r2, #1 494 1.1.2.2 lukem str r0, [r3] 495 1.1.2.2 lukem 496 1.1.2.2 lukem stmfd sp!, {r0-r3} 497 1.1.2.2 lukem ldr r0, Lcpufuncs 498 1.1.2.2 lukem add lr, pc, #Lcs_cache_purged - . - 8 499 1.1.2.4 jdolecek ldr pc, [r0, #CF_IDCACHE_WBINV_ALL] 500 1.1.2.2 lukem 501 1.1.2.2 lukem Lcs_cache_purged: 502 1.1.2.2 lukem ldmfd sp!, {r0-r3} 503 1.1.2.2 lukem 504 1.1.2.2 lukem /* At this point we need to kill IRQ's again. */ 505 1.1.2.2 lukem IRQdisable 506 1.1.2.2 lukem 507 1.1.2.2 lukem /* Interrupts are disabled so we can allow user space accesses again 508 1.1.2.2 lukem * as none will occur until interrupts are re-enabled after the 509 1.1.2.2 lukem * switch. 510 1.1.2.2 lukem */ 511 1.1.2.2 lukem str r2, [r3] 512 1.1.2.2 lukem 513 1.1.2.2 lukem /* Get the user structure for the new process in r1 */ 514 1.1.2.2 lukem ldr r1, [r6, #(P_ADDR)] 515 1.1.2.2 lukem 516 1.1.2.2 lukem /* Get the pagedir physical address for the process. */ 517 1.1.2.2 lukem ldr r0, [r1, #(PCB_PAGEDIR)] 518 1.1.2.2 lukem 519 1.1.2.2 lukem /* Switch the memory to the new process */ 520 1.1.2.2 lukem ldr r3, Lcpufuncs 521 1.1.2.2 lukem add lr, pc, #Lcs_context_switched - . - 8 522 1.1.2.2 lukem ldr pc, [r3, #CF_CONTEXT_SWITCH] 523 1.1.2.2 lukem 524 1.1.2.2 lukem Lcs_context_switched: 525 1.1.2.2 lukem /* 526 1.1.2.2 lukem * This can be optimised... We know we want to go from SVC32 527 1.1.2.2 lukem * mode to UND32 mode 528 1.1.2.2 lukem */ 529 1.1.2.2 lukem mrs r3, cpsr_all 530 1.1.2.2 lukem bic r2, r3, #(PSR_MODE) 531 1.1.2.2 lukem orr r2, r2, #(PSR_UND32_MODE) 532 1.1.2.2 lukem msr cpsr_all, r2 533 1.1.2.2 lukem 534 1.1.2.2 lukem ldr sp, [r1, #(PCB_UND_SP)] 535 1.1.2.2 lukem 536 1.1.2.2 lukem msr cpsr_all, r3 /* Restore the old mode */ 537 1.1.2.2 lukem 538 1.1.2.2 lukem /* Restore all the save registers */ 539 1.1.2.2 lukem add r7, r1, #PCB_R8 540 1.1.2.2 lukem ldmia r7, {r8-r13} 541 1.1.2.2 lukem 542 1.1.2.2 lukem #ifdef ARMFPE 543 1.1.2.2 lukem add r0, r1, #(USER_SIZE) & 0x00ff 544 1.1.2.2 lukem add r0, r0, #(USER_SIZE) & 0xff00 545 1.1.2.2 lukem bl _C_LABEL(arm_fpe_core_changecontext) 546 1.1.2.2 lukem #endif 547 1.1.2.2 lukem 548 1.1.2.2 lukem /* We can enable interrupts again */ 549 1.1.2.2 lukem IRQenable 550 1.1.2.2 lukem 551 1.1.2.2 lukem switch_return: 552 1.1.2.2 lukem 553 1.1.2.2 lukem /* Get the spl level from the stack and update the current spl level */ 554 1.1.2.2 lukem ldr r0, [sp], #0x0004 555 1.1.2.2 lukem bl _C_LABEL(splx) 556 1.1.2.2 lukem 557 1.1.2.2 lukem /* cpu_switch returns the proc it switched to. */ 558 1.1.2.2 lukem mov r0, r6 559 1.1.2.2 lukem 560 1.1.2.2 lukem /* 561 1.1.2.2 lukem * Pull the registers that got pushed when either savectx() or 562 1.1.2.2 lukem * cpu_switch() was called and return. 563 1.1.2.2 lukem */ 564 1.1.2.2 lukem ldmfd sp!, {r4-r7, pc} 565 1.1.2.2 lukem 566 1.1.2.2 lukem Lproc0: 567 1.1.2.2 lukem .word _C_LABEL(proc0) 568 1.1.2.2 lukem 569 1.1.2.2 lukem Lkernel_map: 570 1.1.2.2 lukem .word _C_LABEL(kernel_map) 571 1.1.2.2 lukem 572 1.1.2.2 lukem 573 1.1.2.2 lukem ENTRY(switch_exit) 574 1.1.2.2 lukem /* 575 1.1.2.2 lukem * r0 = proc 576 1.1.2.2 lukem * r1 = proc0 577 1.1.2.2 lukem */ 578 1.1.2.2 lukem 579 1.1.2.2 lukem mov r3, r0 580 1.1.2.2 lukem ldr r1, Lproc0 581 1.1.2.2 lukem 582 1.1.2.2 lukem /* In case we fault */ 583 1.1.2.2 lukem ldr r0, Lcurproc 584 1.1.2.3 thorpej mov r2, #0x00000000 585 1.1.2.2 lukem str r2, [r0] 586 1.1.2.2 lukem 587 1.1.2.2 lukem /* ldr r0, Lcurpcb 588 1.1.2.2 lukem str r2, [r0]*/ 589 1.1.2.2 lukem 590 1.1.2.2 lukem /* Switch to proc0 context */ 591 1.1.2.2 lukem 592 1.1.2.2 lukem stmfd sp!, {r0-r3} 593 1.1.2.2 lukem 594 1.1.2.2 lukem ldr r0, Lcpufuncs 595 1.1.2.2 lukem add lr, pc, #Lse_cache_purged - . - 8 596 1.1.2.4 jdolecek ldr pc, [r0, #CF_IDCACHE_WBINV_ALL] 597 1.1.2.2 lukem 598 1.1.2.2 lukem Lse_cache_purged: 599 1.1.2.2 lukem ldmfd sp!, {r0-r3} 600 1.1.2.2 lukem 601 1.1.2.2 lukem IRQdisable 602 1.1.2.2 lukem 603 1.1.2.2 lukem ldr r2, [r1, #(P_ADDR)] 604 1.1.2.2 lukem ldr r0, [r2, #(PCB_PAGEDIR)] 605 1.1.2.2 lukem 606 1.1.2.2 lukem /* Switch the memory to the new process */ 607 1.1.2.2 lukem ldr r4, Lcpufuncs 608 1.1.2.2 lukem add lr, pc, #Lse_context_switched - . - 8 609 1.1.2.2 lukem ldr pc, [r4, #CF_CONTEXT_SWITCH] 610 1.1.2.2 lukem 611 1.1.2.2 lukem Lse_context_switched: 612 1.1.2.2 lukem /* Restore all the save registers */ 613 1.1.2.2 lukem add r7, r2, #PCB_R8 614 1.1.2.2 lukem ldmia r7, {r8-r13} 615 1.1.2.2 lukem 616 1.1.2.2 lukem /* This is not really needed ! */ 617 1.1.2.2 lukem /* Yes it is for the su and fu routines */ 618 1.1.2.2 lukem ldr r0, Lcurpcb 619 1.1.2.2 lukem str r2, [r0] 620 1.1.2.2 lukem 621 1.1.2.2 lukem IRQenable 622 1.1.2.2 lukem 623 1.1.2.2 lukem /* str r3, [sp, #-0x0004]!*/ 624 1.1.2.2 lukem 625 1.1.2.2 lukem /* 626 1.1.2.2 lukem * Schedule the vmspace and stack to be freed. 627 1.1.2.2 lukem */ 628 1.1.2.2 lukem mov r0, r3 /* exit2(p) */ 629 1.1.2.2 lukem bl _C_LABEL(exit2) 630 1.1.2.2 lukem 631 1.1.2.2 lukem /* Paranoia */ 632 1.1.2.2 lukem ldr r1, Lcurproc 633 1.1.2.3 thorpej mov r0, #0x00000000 634 1.1.2.2 lukem str r0, [r1] 635 1.1.2.2 lukem 636 1.1.2.2 lukem ldr r1, Lproc0 637 1.1.2.2 lukem b switch_search 638 1.1.2.2 lukem 639 1.1.2.2 lukem ENTRY(savectx) 640 1.1.2.2 lukem /* 641 1.1.2.2 lukem * r0 = pcb 642 1.1.2.2 lukem */ 643 1.1.2.2 lukem 644 1.1.2.2 lukem /* Push registers.*/ 645 1.1.2.2 lukem stmfd sp!, {r4-r7, lr} 646 1.1.2.2 lukem 647 1.1.2.2 lukem /* Store all the registers in the process's pcb */ 648 1.1.2.2 lukem add r2, r0, #(PCB_R8) 649 1.1.2.2 lukem stmia r2, {r8-r13} 650 1.1.2.2 lukem 651 1.1.2.2 lukem /* Pull the regs of the stack */ 652 1.1.2.2 lukem ldmfd sp!, {r4-r7, pc} 653 1.1.2.2 lukem 654 1.1.2.2 lukem ENTRY(proc_trampoline) 655 1.1.2.2 lukem add lr, pc, #(trampoline_return - . - 8) 656 1.1.2.2 lukem mov r0, r5 657 1.1.2.2 lukem mov r1, sp 658 1.1.2.2 lukem mov pc, r4 659 1.1.2.2 lukem 660 1.1.2.2 lukem trampoline_return: 661 1.1.2.2 lukem /* Kill irq's */ 662 1.1.2.2 lukem mrs r0, cpsr_all 663 1.1.2.2 lukem orr r0, r0, #(I32_bit) 664 1.1.2.2 lukem msr cpsr_all, r0 665 1.1.2.2 lukem 666 1.1.2.2 lukem PULLFRAME 667 1.1.2.2 lukem 668 1.1.2.2 lukem movs pc, lr /* Exit */ 669 1.1.2.2 lukem 670 1.1.2.3 thorpej .type Lcpu_switch_ffs_table, _ASM_TYPE_OBJECT; 671 1.1.2.2 lukem Lcpu_switch_ffs_table: 672 1.1.2.2 lukem /* same as ffs table but all nums are -1 from that */ 673 1.1.2.2 lukem /* 0 1 2 3 4 5 6 7 */ 674 1.1.2.2 lukem .byte 0, 0, 1, 12, 2, 6, 0, 13 /* 0- 7 */ 675 1.1.2.2 lukem .byte 3, 0, 7, 0, 0, 0, 0, 14 /* 8-15 */ 676 1.1.2.2 lukem .byte 10, 4, 0, 0, 8, 0, 0, 25 /* 16-23 */ 677 1.1.2.2 lukem .byte 0, 0, 0, 0, 0, 21, 27, 15 /* 24-31 */ 678 1.1.2.2 lukem .byte 31, 11, 5, 0, 0, 0, 0, 0 /* 32-39 */ 679 1.1.2.2 lukem .byte 9, 0, 0, 24, 0, 0, 20, 26 /* 40-47 */ 680 1.1.2.2 lukem .byte 30, 0, 0, 0, 0, 23, 0, 19 /* 48-55 */ 681 1.1.2.2 lukem .byte 29, 0, 22, 18, 28, 17, 16, 0 /* 56-63 */ 682 1.1.2.2 lukem 683 1.1.2.2 lukem /* End of cpuswitch.S */ 684
Indexes created Fri Oct 31 11:10:07 GMT 2025