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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. descriptor_t 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.     /* TLS descriptor */
  69.     { 0xffff, 0, 0, AR_PRESENT | AR_DATA | AR_WRITABLE | DPL_USER, 0xf, 0, 0, 1, 1, 0 }
  70. };
  71.  
  72. static idescriptor_t idt[IDT_ITEMS];
  73.  
  74. static tss_t tss;
  75.  
  76. tss_t *tss_p = NULL;
  77.  
  78. /* gdtr is changed by kmp before next CPU is initialized */
  79. ptr_16_32_t bootstrap_gdtr = { .limit = sizeof(gdt), .base = KA2PA((__address) gdt) };
  80. ptr_16_32_t gdtr = { .limit = sizeof(gdt), .base = (__address) gdt };
  81.  
  82. void gdt_setbase(descriptor_t *d, __address base)
  83. {
  84.     d->base_0_15 = base & 0xffff;
  85.     d->base_16_23 = ((base) >> 16) & 0xff;
  86.     d->base_24_31 = ((base) >> 24) & 0xff;
  87. }
  88.  
  89. void gdt_setlimit(descriptor_t *d, __u32 limit)
  90. {
  91.     d->limit_0_15 = limit & 0xffff;
  92.     d->limit_16_19 = (limit >> 16) & 0xf;
  93. }
  94.  
  95. void idt_setoffset(idescriptor_t *d, __address offset)
  96. {
  97.     /*
  98.      * Offset is a linear address.
  99.      */
  100.     d->offset_0_15 = offset & 0xffff;
  101.     d->offset_16_31 = offset >> 16;
  102. }
  103.  
  104. void tss_initialize(tss_t *t)
  105. {
  106.     memsetb((__address) t, sizeof(struct tss), 0);
  107. }
  108.  
  109. /*
  110.  * This function takes care of proper setup of IDT and IDTR.
  111.  */
  112. void idt_init(void)
  113. {
  114.     idescriptor_t *d;
  115.     int i;
  116.  
  117.     for (i = 0; i < IDT_ITEMS; i++) {
  118.         d = &idt[i];
  119.  
  120.         d->unused = 0;
  121.         d->selector = selector(KTEXT_DES);
  122.  
  123.         d->access = AR_PRESENT | AR_INTERRUPT;  /* masking interrupt */
  124.  
  125.         if (i == VECTOR_SYSCALL) {
  126.             /*
  127.              * The syscall interrupt gate must be calleable from userland.
  128.              */
  129.             d->access |= DPL_USER;
  130.         }
  131.        
  132.         idt_setoffset(d, ((__address) interrupt_handlers) + i*interrupt_handler_size);
  133.         exc_register(i, "undef", (iroutine) null_interrupt);
  134.     }
  135.     exc_register(13, "gp_fault", (iroutine) gp_fault);
  136.     exc_register( 7, "nm_fault", (iroutine) nm_fault);
  137.     exc_register(12, "ss_fault", (iroutine) ss_fault);
  138.     exc_register(19, "simd_fp", (iroutine) simd_fp_exception);
  139. }
  140.  
  141.  
  142. /* Clean IOPL(12,13) and NT(14) flags in EFLAGS register */
  143. static void clean_IOPL_NT_flags(void)
  144. {
  145.     __asm__ volatile (
  146.         "pushfl\n"
  147.         "pop %%eax\n"
  148.         "and $0xffff8fff, %%eax\n"
  149.         "push %%eax\n"
  150.         "popfl\n"
  151.         : : : "eax"
  152.     );
  153. }
  154.  
  155. /* Clean AM(18) flag in CR0 register */
  156. static void clean_AM_flag(void)
  157. {
  158.     __asm__ volatile (
  159.         "mov %%cr0, %%eax\n"
  160.         "and $0xfffbffff, %%eax\n"
  161.         "mov %%eax, %%cr0\n"
  162.         : : : "eax"
  163.     );
  164. }
  165.  
  166. void pm_init(void)
  167. {
  168.     descriptor_t *gdt_p = (descriptor_t *) gdtr.base;
  169.     ptr_16_32_t idtr;
  170.  
  171.     /*
  172.      * Update addresses in GDT and IDT to their virtual counterparts.
  173.      */
  174.     idtr.limit = sizeof(idt);
  175.     idtr.base = (__address) idt;
  176.     gdtr_load(&gdtr);
  177.     idtr_load(&idtr);
  178.    
  179.     /*
  180.      * Each CPU has its private GDT and TSS.
  181.      * All CPUs share one IDT.
  182.      */
  183.  
  184.     if (config.cpu_active == 1) {
  185.         idt_init();
  186.         /*
  187.          * NOTE: bootstrap CPU has statically allocated TSS, because
  188.          * the heap hasn't been initialized so far.
  189.          */
  190.         tss_p = &tss;
  191.     }
  192.     else {
  193.         tss_p = (tss_t *) malloc(sizeof(tss_t), FRAME_ATOMIC);
  194.         if (!tss_p)
  195.             panic("could not allocate TSS\n");
  196.     }
  197.  
  198.     tss_initialize(tss_p);
  199.    
  200.     gdt_p[TSS_DES].access = AR_PRESENT | AR_TSS | DPL_KERNEL;
  201.     gdt_p[TSS_DES].special = 1;
  202.     gdt_p[TSS_DES].granularity = 1;
  203.    
  204.     gdt_setbase(&gdt_p[TSS_DES], (__address) tss_p);
  205.     gdt_setlimit(&gdt_p[TSS_DES], sizeof(tss_t) - 1);
  206.  
  207.     /*
  208.      * As of this moment, the current CPU has its own GDT pointing
  209.      * to its own TSS. We just need to load the TR register.
  210.      */
  211.     tr_load(selector(TSS_DES));
  212.    
  213.     clean_IOPL_NT_flags();    /* Disable I/O on nonprivileged levels */
  214.     clean_AM_flag();          /* Disable alignment check */
  215. }
  216.  
  217. void set_tls_desc(__address tls)
  218. {
  219.     ptr_16_32_t cpugdtr;
  220.     descriptor_t *gdt_p;
  221.  
  222.     gdtr_store(&cpugdtr);
  223.     gdt_p = (descriptor_t *) cpugdtr.base;
  224.     gdt_setbase(&gdt_p[TLS_DES], tls);
  225.     /* Reload gdt register to update GS in CPU */
  226.     gdtr_load(&cpugdtr);
  227. }
  228.