arch/i386/kernel/entry_trampoline.c

   1 /*
   2  * linux/arch/i386/kernel/entry_trampoline.c
   3  *
   4  * (C) Copyright 2003 Ingo Molnar
   5  *
   6  * This file contains the needed support code for 4GB userspace
   7  */
   8
   9 #include <linux/init.h>
  10 #include <linux/smp.h>
  11 #include <linux/mm.h>
  12 #include <linux/sched.h>
  13 #include <linux/kernel.h>
  14 #include <linux/string.h>
  15 #include <linux/highmem.h>
  16 #include <asm/desc.h>
  17 #include <asm/atomic_kmap.h>
  18
  19 extern char __entry_tramp_start, __entry_tramp_end, __start___entry_text;
  20
  21 void __init init_entry_mappings(void)
  22 {
  23 #ifdef CONFIG_X86_HIGH_ENTRY
  24
  25         void *tramp;
  26         int p;
  27
  28         /*
  29          * We need a high IDT and GDT for the 4G/4G split:
  30          */
  31         trap_init_virtual_IDT();
  32
  33         __set_fixmap(FIX_ENTRY_TRAMPOLINE_0, __pa((unsigned long)&__entry_tramp_start), PAGE_KERNEL_EXEC);
  34         __set_fixmap(FIX_ENTRY_TRAMPOLINE_1, __pa((unsigned long)&__entry_tramp_start) + PAGE_SIZE, PAGE_KERNEL_EXEC);
  35         tramp = (void *)fix_to_virt(FIX_ENTRY_TRAMPOLINE_0);
  36
  37         printk("mapped 4G/4G trampoline to %p.\n", tramp);
  38         BUG_ON((void *)&__start___entry_text != tramp);
  39         /*
  40          * Virtual kernel stack:
  41          */
  42         BUG_ON(__kmap_atomic_vaddr(KM_VSTACK_TOP) & (THREAD_SIZE-1));
  43         BUG_ON(sizeof(struct desc_struct)*NR_CPUS*GDT_ENTRIES > 2*PAGE_SIZE);
  44         BUG_ON((unsigned int)&__entry_tramp_end - (unsigned int)&__entry_tramp_start > 2*PAGE_SIZE);
  45
  46         /*
  47          * set up the initial thread's virtual stack related
  48          * fields:
  49          */
  50         for (p = 0; p < ARRAY_SIZE(current->thread.stack_page); p++)
  51                 current->thread.stack_page[p] = virt_to_page((char *)current->thread_info + (p*PAGE_SIZE));
  52
  53         current->thread_info->virtual_stack = (void *)__kmap_atomic_vaddr(KM_VSTACK_TOP);
  54
  55         for (p = 0; p < ARRAY_SIZE(current->thread.stack_page); p++) {
  56                 __kunmap_atomic_type(KM_VSTACK_TOP-p);
  57                 __kmap_atomic(current->thread.stack_page[p], KM_VSTACK_TOP-p);
  58         }
  59 #endif
  60         current->thread_info->real_stack = (void *)current->thread_info;
  61         current->thread_info->user_pgd = NULL;
  62         current->thread.esp0 = (unsigned long)current->thread_info->real_stack + THREAD_SIZE;
  63 }
  64
  65
  66
  67 void __init entry_trampoline_setup(void)
  68 {
  69         /*
  70          * old IRQ entries set up by the boot code will still hang
  71          * around - they are a sign of hw trouble anyway, now they'll
  72          * produce a double fault message.
  73          */
  74         trap_init_virtual_GDT();
  75 }