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  1. /*
  2.  * Copyright (C) 2001-2004 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. #include <arch/pm.h>
  30. #include <config.h>
  31. #include <arch/types.h>
  32. #include <typedefs.h>
  33. #include <arch/interrupt.h>
  34. #include <arch/asm.h>
  35. #include <arch/context.h>
  36. #include <panic.h>
  37. #include <arch/mm/page.h>
  38. #include <mm/slab.h>
  39. #include <memstr.h>
  40. #include <arch/boot/boot.h>
  41. #include <interrupt.h>
  42.  
  43. /*
  44.  * Early ia32 configuration functions and data structures.
  45.  */
  46.  
  47. /*
  48.  * We have no use for segmentation so we set up flat mode. In this
  49.  * mode, we use, for each privilege level, two segments spanning the
  50.  * whole memory. One is for code and one is for data.
  51.  *
  52.  * One is for GS register which holds pointer to the TLS thread
  53.  * structure in it's base.
  54.  */
  55. struct descriptor gdt[GDT_ITEMS] = {
  56.     /* NULL descriptor */
  57.     { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
  58.     /* KTEXT descriptor */
  59.     { 0xffff, 0, 0, AR_PRESENT | AR_CODE | DPL_KERNEL, 0xf, 0, 0, 1, 1, 0 },
  60.     /* KDATA descriptor */
  61.     { 0xffff, 0, 0, AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_KERNEL, 0xf, 0, 0, 1, 1, 0 },
  62.     /* UTEXT descriptor */
  63.     { 0xffff, 0, 0, AR_PRESENT | AR_CODE | DPL_USER, 0xf, 0, 0, 1, 1, 0 },
  64.     /* UDATA descriptor */
  65.     { 0xffff, 0, 0, AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_USER, 0xf, 0, 0, 1, 1, 0 },
  66.     /* TSS descriptor - set up will be completed later */
  67.     { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
  68.     { 0xffff, 0, 0, AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_USER, 0xf, 0, 0, 1, 1, 0 }
  69. };
  70.  
  71. static struct idescriptor idt[IDT_ITEMS];
  72.  
  73. static struct tss tss;
  74.  
  75. struct tss *tss_p = NULL;
  76.  
  77. /* gdtr is changed by kmp before next CPU is initialized */
  78. struct ptr_16_32 bootstrap_gdtr = { .limit = sizeof(gdt), .base = KA2PA((__address) gdt) };
  79. struct ptr_16_32 gdtr = { .limit = sizeof(gdt), .base = (__address) gdt };
  80.  
  81. void gdt_setbase(struct descriptor *d, __address base)
  82. {
  83.     d->base_0_15 = base & 0xffff;
  84.     d->base_16_23 = ((base) >> 16) & 0xff;
  85.     d->base_24_31 = ((base) >> 24) & 0xff;
  86. }
  87.  
  88. void gdt_setlimit(struct descriptor *d, __u32 limit)
  89. {
  90.     d->limit_0_15 = limit & 0xffff;
  91.     d->limit_16_19 = (limit >> 16) & 0xf;
  92. }
  93.  
  94. void idt_setoffset(struct idescriptor *d, __address offset)
  95. {
  96.     /*
  97.      * Offset is a linear address.
  98.      */
  99.     d->offset_0_15 = offset & 0xffff;
  100.     d->offset_16_31 = offset >> 16;
  101. }
  102.  
  103. void tss_initialize(struct tss *t)
  104. {
  105.     memsetb((__address) t, sizeof(struct tss), 0);
  106. }
  107.  
  108. /*
  109.  * This function takes care of proper setup of IDT and IDTR.
  110.  */
  111. void idt_init(void)
  112. {
  113.     struct idescriptor *d;
  114.     int i;
  115.  
  116.     for (i = 0; i < IDT_ITEMS; i++) {
  117.         d = &idt[i];
  118.  
  119.         d->unused = 0;
  120.         d->selector = selector(KTEXT_DES);
  121.  
  122.         d->access = AR_PRESENT | AR_INTERRUPT;  /* masking interrupt */
  123.  
  124.         if (i == VECTOR_SYSCALL) {
  125.             /*
  126.              * The syscall interrupt gate must be calleable from userland.
  127.              */
  128.             d->access |= DPL_USER;
  129.         }
  130.        
  131.         idt_setoffset(d, ((__address) interrupt_handlers) + i*interrupt_handler_size);
  132.         exc_register(i, "undef", (iroutine) null_interrupt);
  133.     }
  134.     exc_register(13, "gp_fault", (iroutine) gp_fault);
  135.     exc_register( 7, "nm_fault", (iroutine) nm_fault);
  136.     exc_register(12, "ss_fault", (iroutine) ss_fault);
  137.     exc_register(19, "simd_fp", (iroutine) simd_fp_exception);
  138. }
  139.  
  140.  
  141. /* Clean IOPL(12,13) and NT(14) flags in EFLAGS register */
  142. static void clean_IOPL_NT_flags(void)
  143. {
  144.     asm
  145.     (
  146.         "pushfl;"
  147.         "pop %%eax;"
  148.         "and $0xffff8fff,%%eax;"
  149.         "push %%eax;"
  150.         "popfl;"
  151.         :
  152.         :
  153.         :"%eax"
  154.     );
  155. }
  156.  
  157. /* Clean AM(18) flag in CR0 register */
  158. static void clean_AM_flag(void)
  159. {
  160.     asm
  161.     (
  162.         "mov %%cr0,%%eax;"
  163.         "and $0xFFFBFFFF,%%eax;"
  164.         "mov %%eax,%%cr0;"
  165.         :
  166.         :
  167.         :"%eax"
  168.     );
  169. }
  170.  
  171. void pm_init(void)
  172. {
  173.     struct descriptor *gdt_p = (struct descriptor *) gdtr.base;
  174.     struct ptr_16_32 idtr;
  175.  
  176.     /*
  177.      * Update addresses in GDT and IDT to their virtual counterparts.
  178.      */
  179.     idtr.limit = sizeof(idt);
  180.     idtr.base = (__address) idt;
  181.     __asm__ volatile ("lgdt %0\n" : : "m" (gdtr));
  182.     __asm__ volatile ("lidt %0\n" : : "m" (idtr)); 
  183.    
  184.     /*
  185.      * Each CPU has its private GDT and TSS.
  186.      * All CPUs share one IDT.
  187.      */
  188.  
  189.     if (config.cpu_active == 1) {
  190.         idt_init();
  191.         /*
  192.          * NOTE: bootstrap CPU has statically allocated TSS, because
  193.          * the heap hasn't been initialized so far.
  194.          */
  195.         tss_p = &tss;
  196.     }
  197.     else {
  198.         tss_p = (struct tss *) malloc(sizeof(struct tss),FRAME_ATOMIC);
  199.         if (!tss_p)
  200.             panic("could not allocate TSS\n");
  201.     }
  202.  
  203.     tss_initialize(tss_p);
  204.    
  205.     gdt_p[TSS_DES].access = AR_PRESENT | AR_TSS | DPL_KERNEL;
  206.     gdt_p[TSS_DES].special = 1;
  207.     gdt_p[TSS_DES].granularity = 1;
  208.    
  209.     gdt_setbase(&gdt_p[TSS_DES], (__address) tss_p);
  210.     gdt_setlimit(&gdt_p[TSS_DES], sizeof(struct tss) - 1);
  211.  
  212.     /*
  213.      * As of this moment, the current CPU has its own GDT pointing
  214.      * to its own TSS. We just need to load the TR register.
  215.      */
  216.     __asm__ volatile ("ltr %0" : : "r" ((__u16) selector(TSS_DES)));
  217.    
  218.     clean_IOPL_NT_flags();    /* Disable I/O on nonprivileged levels */
  219.     clean_AM_flag();          /* Disable alignment check */
  220. }
  221.  
  222. void set_tls_desc(__address tls)
  223. {
  224.     struct ptr_16_32 cpugdtr;
  225.     struct descriptor *gdt_p = (struct descriptor *) cpugdtr.base;
  226.  
  227.     __asm__ volatile ("sgdt %0\n" : : "m" (cpugdtr));
  228.  
  229.     gdt_setbase(&gdt_p[TLS_DES], tls);
  230.     /* Reload gdt register to update GS in CPU */
  231.     __asm__ volatile ("lgdt %0\n" : : "m" (cpugdtr));
  232. }
  233.