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  1. /*
  2.  * Copyright (C) 2001-2004 Jakub Jermar
  3.  * Copyright (C) 2005-2006 Ondrej Palkovsky
  4.  * All rights reserved.
  5.  *
  6.  * Redistribution and use in source and binary forms, with or without
  7.  * modification, are permitted provided that the following conditions
  8.  * are met:
  9.  *
  10.  * - Redistributions of source code must retain the above copyright
  11.  *   notice, this list of conditions and the following disclaimer.
  12.  * - Redistributions in binary form must reproduce the above copyright
  13.  *   notice, this list of conditions and the following disclaimer in the
  14.  *   documentation and/or other materials provided with the distribution.
  15.  * - The name of the author may not be used to endorse or promote products
  16.  *   derived from this software without specific prior written permission.
  17.  *
  18.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  19.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  20.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  21.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  22.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  23.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28.  */
  29.  
  30. #include <arch/pm.h>
  31. #include <arch/mm/page.h>
  32. #include <arch/types.h>
  33. #include <arch/interrupt.h>
  34. #include <arch/asm.h>
  35. #include <interrupt.h>
  36.  
  37. #include <config.h>
  38.  
  39. #include <memstr.h>
  40. #include <mm/heap.h>
  41. #include <debug.h>
  42.  
  43. /*
  44.  * There is no segmentation in long mode so we set up flat mode. In this
  45.  * mode, we use, for each privilege level, two segments spanning the
  46.  * whole memory. One is for code and one is for data.
  47.  */
  48.  
  49. struct descriptor gdt[GDT_ITEMS] = {
  50.     /* NULL descriptor */
  51.     { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
  52.     /* KTEXT descriptor */
  53.     { .limit_0_15  = 0xffff,
  54.       .base_0_15   = 0,
  55.       .base_16_23  = 0,
  56.       .access      = AR_PRESENT | AR_CODE | DPL_KERNEL | AR_READABLE ,
  57.       .limit_16_19 = 0xf,
  58.       .available   = 0,
  59.       .longmode    = 1,
  60.       .special     = 0,
  61.       .granularity = 1,
  62.       .base_24_31  = 0 },
  63.     /* KDATA descriptor */
  64.     { .limit_0_15  = 0xffff,
  65.       .base_0_15   = 0,
  66.       .base_16_23  = 0,
  67.       .access      = AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_KERNEL,
  68.       .limit_16_19 = 0xf,
  69.       .available   = 0,
  70.       .longmode    = 0,
  71.       .special     = 0,
  72.       .granularity = 1,
  73.       .base_24_31  = 0 },
  74.     /* UTEXT descriptor */
  75.     { .limit_0_15  = 0xffff,
  76.       .base_0_15   = 0,
  77.       .base_16_23  = 0,
  78.       .access      = AR_PRESENT | AR_CODE | DPL_USER,
  79.       .limit_16_19 = 0xf,
  80.       .available   = 0,
  81.       .longmode    = 1,
  82.       .special     = 0,
  83.       .granularity = 1,
  84.       .base_24_31  = 0 },
  85.     /* UDATA descriptor */
  86.     { .limit_0_15  = 0xffff,
  87.       .base_0_15   = 0,
  88.       .base_16_23  = 0,
  89.       .access      = AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_USER,
  90.       .limit_16_19 = 0xf,
  91.       .available   = 0,
  92.       .longmode    = 0,
  93.       .special     = 1,
  94.       .granularity = 1,
  95.       .base_24_31  = 0 },
  96.     /* KTEXT 32-bit protected, for protected mode before long mode */
  97.     { .limit_0_15  = 0xffff,
  98.       .base_0_15   = 0,
  99.       .base_16_23  = 0,
  100.       .access      = AR_PRESENT | AR_CODE | DPL_KERNEL | AR_READABLE,
  101.       .limit_16_19 = 0xf,
  102.       .available   = 0,
  103.       .longmode    = 0,
  104.       .special     = 1,
  105.       .granularity = 1,
  106.       .base_24_31  = 0 },
  107.     /* TSS descriptor - set up will be completed later,
  108.      * on AMD64 it is 64-bit - 2 items in table */
  109.     { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
  110.     { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
  111. };
  112.  
  113. struct idescriptor idt[IDT_ITEMS];
  114.  
  115. struct ptr_16_64 gdtr = {.limit = sizeof(gdt), .base= (__u64) gdt };
  116. struct ptr_16_64 idtr = {.limit = sizeof(idt), .base= (__u64) idt };
  117.  
  118. static struct tss tss;
  119. struct tss *tss_p = NULL;
  120.  
  121. void gdt_tss_setbase(struct descriptor *d, __address base)
  122. {
  123.     struct tss_descriptor *td = (struct tss_descriptor *) d;
  124.  
  125.     td->base_0_15 = base & 0xffff;
  126.     td->base_16_23 = ((base) >> 16) & 0xff;
  127.     td->base_24_31 = ((base) >> 24) & 0xff;
  128.     td->base_32_63 = ((base) >> 32);
  129. }
  130.  
  131. void gdt_tss_setlimit(struct descriptor *d, __u32 limit)
  132. {
  133.     struct tss_descriptor *td = (struct tss_descriptor *) d;
  134.  
  135.     td->limit_0_15 = limit & 0xffff;
  136.     td->limit_16_19 = (limit >> 16) & 0xf;
  137. }
  138.  
  139. void idt_setoffset(struct idescriptor *d, __address offset)
  140. {
  141.     /*
  142.      * Offset is a linear address.
  143.      */
  144.     d->offset_0_15 = offset & 0xffff;
  145.     d->offset_16_31 = offset >> 16 & 0xffff;
  146.     d->offset_32_63 = offset >> 32;
  147. }
  148.  
  149. void tss_initialize(struct tss *t)
  150. {
  151.     memsetb((__address) t, sizeof(struct tss), 0);
  152. }
  153.  
  154. /*
  155.  * This function takes care of proper setup of IDT and IDTR.
  156.  */
  157. void idt_init(void)
  158. {
  159.     struct idescriptor *d;
  160.     int i;
  161.  
  162.     for (i = 0; i < IDT_ITEMS; i++) {
  163.         d = &idt[i];
  164.  
  165.         d->unused = 0;
  166.         d->selector = gdtselector(KTEXT_DES);
  167.  
  168.         d->present = 1;
  169.         d->type = AR_INTERRUPT; /* masking interrupt */
  170.  
  171.         idt_setoffset(d, ((__address) interrupt_handlers) + i*interrupt_handler_size);
  172.         exc_register(i, "undef", (iroutine)null_interrupt);
  173.     }
  174.     exc_register(13, "gp_fault", gp_fault);
  175.     exc_register( 7, "nm_fault", nm_fault);
  176.     exc_register(12, "ss_fault", ss_fault);
  177. }
  178.  
  179. /** Initialize segmentation - code/data/idt tables
  180.  *
  181.  */
  182. void pm_init(void)
  183. {
  184.     struct descriptor *gdt_p = (struct descriptor *) gdtr.base;
  185.     struct tss_descriptor *tss_desc;
  186.  
  187.     /*
  188.      * Each CPU has its private GDT and TSS.
  189.      * All CPUs share one IDT.
  190.      */
  191.  
  192.     if (config.cpu_active == 1) {
  193.         idt_init();
  194.         /*
  195.          * NOTE: bootstrap CPU has statically allocated TSS, because
  196.          * the heap hasn't been initialized so far.
  197.          */
  198.         tss_p = &tss;
  199.     }
  200.     else {
  201.         tss_p = (struct tss *) malloc(sizeof(struct tss));
  202.         if (!tss_p)
  203.             panic("could not allocate TSS\n");
  204.     }
  205.  
  206.     tss_initialize(tss_p);
  207.  
  208.     tss_desc = (struct tss_descriptor *) (&gdt_p[TSS_DES]);
  209.     tss_desc->present = 1;
  210.     tss_desc->type = AR_TSS;
  211.     tss_desc->dpl = PL_KERNEL;
  212.    
  213.     gdt_tss_setbase(&gdt_p[TSS_DES], (__address) tss_p);
  214.     gdt_tss_setlimit(&gdt_p[TSS_DES], sizeof(struct tss) - 1);
  215.  
  216.     __asm__("lgdt %0" : : "m"(gdtr));
  217.     __asm__("lidt %0" : : "m"(idtr));
  218.     /*
  219.      * As of this moment, the current CPU has its own GDT pointing
  220.      * to its own TSS. We just need to load the TR register.
  221.      */
  222.     __asm__("ltr %0" : : "r" ((__u16) gdtselector(TSS_DES)));
  223. }
  224.