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Annotation of XNU/osfmk/i386/mp_desc.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
        !             3:  *
        !             4:  * @APPLE_LICENSE_HEADER_START@
        !             5:  * 
        !             6:  * The contents of this file constitute Original Code as defined in and
        !             7:  * are subject to the Apple Public Source License Version 1.1 (the
        !             8:  * "License").  You may not use this file except in compliance with the
        !             9:  * License.  Please obtain a copy of the License at
        !            10:  * http://www.apple.com/publicsource and read it before using this file.
        !            11:  * 
        !            12:  * This Original Code and all software distributed under the License are
        !            13:  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
        !            14:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
        !            15:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
        !            16:  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
        !            17:  * License for the specific language governing rights and limitations
        !            18:  * under the License.
        !            19:  * 
        !            20:  * @APPLE_LICENSE_HEADER_END@
        !            21:  */
        !            22: /*
        !            23:  * @OSF_COPYRIGHT@
        !            24:  */
        !            25: /* 
        !            26:  * Mach Operating System
        !            27:  * Copyright (c) 1991,1990 Carnegie Mellon University
        !            28:  * All Rights Reserved.
        !            29:  * 
        !            30:  * Permission to use, copy, modify and distribute this software and its
        !            31:  * documentation is hereby granted, provided that both the copyright
        !            32:  * notice and this permission notice appear in all copies of the
        !            33:  * software, derivative works or modified versions, and any portions
        !            34:  * thereof, and that both notices appear in supporting documentation.
        !            35:  * 
        !            36:  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
        !            37:  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
        !            38:  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
        !            39:  * 
        !            40:  * Carnegie Mellon requests users of this software to return to
        !            41:  * 
        !            42:  *  Software Distribution Coordinator  or  [email protected]
        !            43:  *  School of Computer Science
        !            44:  *  Carnegie Mellon University
        !            45:  *  Pittsburgh PA 15213-3890
        !            46:  * 
        !            47:  * any improvements or extensions that they make and grant Carnegie Mellon
        !            48:  * the rights to redistribute these changes.
        !            49:  */
        !            50: 
        !            51: /*
        !            52:  */
        !            53: 
        !            54: #include <cpus.h>
        !            55: 
        !            56: #if    NCPUS > 1
        !            57: 
        !            58: #include <kern/cpu_number.h>
        !            59: #include <kern/cpu_data.h>
        !            60: #include <mach/machine.h>
        !            61: #include <vm/vm_kern.h>
        !            62: 
        !            63: #include <i386/mp_desc.h>
        !            64: #include <i386/lock.h>
        !            65: #include <i386/misc_protos.h>
        !            66: 
        !            67: #include <kern/misc_protos.h>
        !            68: 
        !            69: #include <mach_kdb.h>
        !            70: 
        !            71: /*
        !            72:  * The i386 needs an interrupt stack to keep the PCB stack from being
        !            73:  * overrun by interrupts.  All interrupt stacks MUST lie at lower addresses
        !            74:  * than any thread`s kernel stack.
        !            75:  */
        !            76: 
        !            77: /*
        !            78:  * Addresses of bottom and top of interrupt stacks.
        !            79:  */
        !            80: vm_offset_t    interrupt_stack[NCPUS];
        !            81: vm_offset_t    int_stack_top[NCPUS];
        !            82: 
        !            83: /*
        !            84:  * Barrier address.
        !            85:  */
        !            86: vm_offset_t    int_stack_high;
        !            87: 
        !            88: /*
        !            89:  * First cpu`s interrupt stack.
        !            90:  */
        !            91: extern char            intstack[];     /* bottom */
        !            92: extern char            eintstack[];    /* top */
        !            93: 
        !            94: /*
        !            95:  * We allocate interrupt stacks from physical memory.
        !            96:  */
        !            97: extern
        !            98: vm_offset_t    avail_start;
        !            99: 
        !           100: /*
        !           101:  * Multiprocessor i386/i486 systems use a separate copy of the
        !           102:  * GDT, IDT, LDT, and kernel TSS per processor.  The first three
        !           103:  * are separate to avoid lock contention: the i386 uses locked
        !           104:  * memory cycles to access the descriptor tables.  The TSS is
        !           105:  * separate since each processor needs its own kernel stack,
        !           106:  * and since using a TSS marks it busy.
        !           107:  */
        !           108: 
        !           109: /*
        !           110:  * Allocated descriptor tables.
        !           111:  */
        !           112: struct mp_desc_table   *mp_desc_table[NCPUS] = { 0 };
        !           113: 
        !           114: /*
        !           115:  * Pointer to TSS for access in load_context.
        !           116:  */
        !           117: struct i386_tss                *mp_ktss[NCPUS] = { 0 };
        !           118: 
        !           119: #if    MACH_KDB
        !           120: /*
        !           121:  * Pointer to TSS for debugger use.
        !           122:  */
        !           123: struct i386_tss                *mp_dbtss[NCPUS] = { 0 };
        !           124: #endif /* MACH_KDB */
        !           125: 
        !           126: /*
        !           127:  * Pointer to GDT to reset the KTSS busy bit.
        !           128:  */
        !           129: struct fake_descriptor *mp_gdt[NCPUS] = { 0 };
        !           130: struct fake_descriptor *mp_idt[NCPUS] = { 0 };
        !           131: 
        !           132: /*
        !           133:  * Allocate and initialize the per-processor descriptor tables.
        !           134:  */
        !           135: 
        !           136: struct fake_descriptor ldt_desc_pattern = {
        !           137:        (unsigned int) 0,
        !           138:        LDTSZ * sizeof(struct fake_descriptor) - 1,
        !           139:        0,
        !           140:        ACC_P|ACC_PL_K|ACC_LDT
        !           141: };
        !           142: struct fake_descriptor tss_desc_pattern = {
        !           143:        (unsigned int) 0,
        !           144:        sizeof(struct i386_tss),
        !           145:        0,
        !           146:        ACC_P|ACC_PL_K|ACC_TSS
        !           147: };
        !           148: 
        !           149: struct fake_descriptor cpudata_desc_pattern = {
        !           150:        (unsigned int) 0,
        !           151:        sizeof(cpu_data_t)-1,
        !           152:        SZ_32,
        !           153:        ACC_P|ACC_PL_K|ACC_DATA_W
        !           154: };
        !           155: 
        !           156: struct mp_desc_table *
        !           157: mp_desc_init(
        !           158:        int     mycpu)
        !           159: {
        !           160:        register struct mp_desc_table *mpt;
        !           161: 
        !           162:        if (mycpu == master_cpu) {
        !           163:            /*
        !           164:             * Master CPU uses the tables built at boot time.
        !           165:             * Just set the TSS and GDT pointers.
        !           166:             */
        !           167:            mp_ktss[mycpu] = &ktss;
        !           168: #if    MACH_KDB
        !           169:            mp_dbtss[mycpu] = &dbtss;
        !           170: #endif /* MACH_KDB */
        !           171:            mp_gdt[mycpu] = gdt;
        !           172:            mp_idt[mycpu] = idt;
        !           173:            return 0;
        !           174:        }
        !           175:        else {
        !           176:            mpt = mp_desc_table[mycpu];
        !           177:            mp_ktss[mycpu] = &mpt->ktss;
        !           178:            mp_gdt[mycpu] = mpt->gdt;
        !           179:            mp_idt[mycpu] = mpt->idt;
        !           180: 
        !           181:            /*
        !           182:             * Copy the tables
        !           183:             */
        !           184:            bcopy((char *)idt,
        !           185:                  (char *)mpt->idt,
        !           186:                  sizeof(idt));
        !           187:            bcopy((char *)gdt,
        !           188:                  (char *)mpt->gdt,
        !           189:                  sizeof(gdt));
        !           190:            bcopy((char *)ldt,
        !           191:                  (char *)mpt->ldt,
        !           192:                  sizeof(ldt));
        !           193:            bzero((char *)&mpt->ktss,
        !           194:                  sizeof(struct i386_tss));
        !           195:            bzero((char *)&cpu_data[mycpu],
        !           196:                  sizeof(cpu_data_t));
        !           197: #if    MACH_KDB
        !           198:            mp_dbtss[mycpu] = &mpt->dbtss;
        !           199:            bcopy((char *)&dbtss,
        !           200:                  (char *)&mpt->dbtss,
        !           201:                  sizeof(struct i386_tss));
        !           202: #endif /* MACH_KDB */
        !           203: 
        !           204:            /*
        !           205:             * Fix up the entries in the GDT to point to
        !           206:             * this LDT and this TSS.
        !           207:             */
        !           208:            mpt->gdt[sel_idx(KERNEL_LDT)] = ldt_desc_pattern;
        !           209:            mpt->gdt[sel_idx(KERNEL_LDT)].offset =
        !           210:                LINEAR_KERNEL_ADDRESS + (unsigned int) mpt->ldt;
        !           211:            fix_desc(&mpt->gdt[sel_idx(KERNEL_LDT)], 1);
        !           212: 
        !           213:            mpt->gdt[sel_idx(KERNEL_TSS)] = tss_desc_pattern;
        !           214:            mpt->gdt[sel_idx(KERNEL_TSS)].offset =
        !           215:                LINEAR_KERNEL_ADDRESS + (unsigned int) &mpt->ktss;
        !           216:            fix_desc(&mpt->gdt[sel_idx(KERNEL_TSS)], 1);
        !           217: 
        !           218:            mpt->gdt[sel_idx(CPU_DATA)] = cpudata_desc_pattern;
        !           219:            mpt->gdt[sel_idx(CPU_DATA)].offset =
        !           220:                LINEAR_KERNEL_ADDRESS + (unsigned int) &cpu_data[mycpu];
        !           221:            fix_desc(&mpt->gdt[sel_idx(CPU_DATA)], 1);
        !           222: 
        !           223: #if    MACH_KDB
        !           224:            mpt->gdt[sel_idx(DEBUG_TSS)] = tss_desc_pattern;
        !           225:            mpt->gdt[sel_idx(DEBUG_TSS)].offset =
        !           226:                    LINEAR_KERNEL_ADDRESS + (unsigned int) &mpt->dbtss;
        !           227:            fix_desc(&mpt->gdt[sel_idx(DEBUG_TSS)], 1);
        !           228: 
        !           229:            mpt->dbtss.esp0 = (int)(db_task_stack_store +
        !           230:                    (INTSTACK_SIZE * (mycpu + 1)) - sizeof (natural_t));
        !           231:            mpt->dbtss.esp = mpt->dbtss.esp0;
        !           232:            mpt->dbtss.eip = (int)&db_task_start;
        !           233: #endif /* MACH_KDB */
        !           234: 
        !           235:            mpt->ktss.ss0 = KERNEL_DS;
        !           236:            mpt->ktss.io_bit_map_offset = 0x0FFF;       /* no IO bitmap */
        !           237: 
        !           238:            return mpt;
        !           239:        }
        !           240: }
        !           241: 
        !           242: /*
        !           243:  * Called after all CPUs have been found, but before the VM system
        !           244:  * is running.  The machine array must show which CPUs exist.
        !           245:  */
        !           246: void
        !           247: interrupt_stack_alloc(void)
        !           248: {
        !           249:        register int            i;
        !           250:        int                     cpu_count;
        !           251:        vm_offset_t             stack_start;
        !           252:        struct mp_desc_table    *mpt;
        !           253: 
        !           254:        /*
        !           255:         * Count the number of CPUs.
        !           256:         */
        !           257:        cpu_count = 0;
        !           258:        for (i = 0; i < NCPUS; i++)
        !           259:            if (machine_slot[i].is_cpu)
        !           260:                cpu_count++;
        !           261: 
        !           262:        /*
        !           263:         * Allocate an interrupt stack for each CPU except for
        !           264:         * the master CPU (which uses the bootstrap stack)
        !           265:         */
        !           266:        stack_start = phystokv(avail_start);
        !           267:        avail_start = round_page(avail_start + INTSTACK_SIZE*(cpu_count-1));
        !           268:        bzero((char *)stack_start, INTSTACK_SIZE*(cpu_count-1));
        !           269: 
        !           270:        /*
        !           271:         * Set up pointers to the top of the interrupt stack.
        !           272:         */
        !           273:        for (i = 0; i < NCPUS; i++) {
        !           274:            if (i == master_cpu) {
        !           275:                interrupt_stack[i] = (vm_offset_t) intstack;
        !           276:                int_stack_top[i]   = (vm_offset_t) eintstack;
        !           277:            }
        !           278:            else if (machine_slot[i].is_cpu) {
        !           279:                interrupt_stack[i] = stack_start;
        !           280:                int_stack_top[i]   = stack_start + INTSTACK_SIZE;
        !           281: 
        !           282:                stack_start += INTSTACK_SIZE;
        !           283:            }
        !           284:        }
        !           285: 
        !           286:        /*
        !           287:         * Allocate descriptor tables for each CPU except for
        !           288:         * the master CPU (which already has them initialized)
        !           289:         */
        !           290: 
        !           291:        mpt = (struct mp_desc_table *) phystokv(avail_start);
        !           292:        avail_start = round_page((vm_offset_t)avail_start +
        !           293:                                 sizeof(struct mp_desc_table)*(cpu_count-1));
        !           294:        for (i = 0; i < NCPUS; i++)
        !           295:            if (i != master_cpu)
        !           296:                mp_desc_table[i] = mpt++;
        !           297: 
        !           298: 
        !           299:        /*
        !           300:         * Set up the barrier address.  All thread stacks MUST
        !           301:         * be above this address.
        !           302:         */
        !           303:        /*
        !           304:         * intstack is at higher addess than stack_start for AT mps
        !           305:         * so int_stack_high must point at eintstack.
        !           306:         * XXX
        !           307:         * But what happens if a kernel stack gets allocated below
        !           308:         * 1 Meg ? Probably never happens, there is only 640 K available
        !           309:         * There.
        !           310:         */
        !           311:        int_stack_high = (vm_offset_t) eintstack;
        !           312: }
        !           313: 
        !           314: #endif /* NCPUS > 1 */

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