src/system/kernel/commpage.cpp

   1 /*
   2  * Copyright 2007, Travis Geiselbrecht. All rights reserved.
   3  * Distributed under the terms of the MIT License.
   4  */
   5
   6 #include <commpage.h>
   7
   8 #include <string.h>
   9
  10 #include <KernelExport.h>
  11
  12 #include <elf.h>
  13 #include <vm/vm.h>
  14 #include <vm/vm_types.h>
  15
  16
  17 static area_id  sCommPageArea;
  18 static addr_t*  sCommPageAddress;
  19 static void*    sFreeCommPageSpace;
  20 static image_id sCommPageImage;
  21
  22
  23 #define ALIGN_ENTRY(pointer)    (void*)ROUNDUP((addr_t)(pointer), 8)
  24
  25
  26 void*
  27 allocate_commpage_entry(int entry, size_t size)
  28 {
  29         void* space = sFreeCommPageSpace;
  30         sFreeCommPageSpace = ALIGN_ENTRY((addr_t)sFreeCommPageSpace + size);
  31         sCommPageAddress[entry] = (addr_t)space - (addr_t)sCommPageAddress;
  32         dprintf("allocate_commpage_entry(%d, %lu) -> %p\n", entry, size,
  33                 (void*)sCommPageAddress[entry]);
  34         return space;
  35 }
  36
  37
  38 addr_t
  39 fill_commpage_entry(int entry, const void* copyFrom, size_t size)
  40 {
  41         void* space = allocate_commpage_entry(entry, size);
  42         memcpy(space, copyFrom, size);
  43         return (addr_t)space - (addr_t)sCommPageAddress;
  44 }
  45
  46
  47 image_id
  48 get_commpage_image()
  49 {
  50         return sCommPageImage;
  51 }
  52
  53
  54 area_id
  55 clone_commpage_area(team_id team, void** address)
  56 {
  57         *address = (void*)KERNEL_USER_DATA_BASE;
  58         return vm_clone_area(team, "commpage", address,
  59                 B_RANDOMIZED_BASE_ADDRESS, B_READ_AREA | B_EXECUTE_AREA | B_KERNEL_AREA,
  60                 REGION_PRIVATE_MAP, sCommPageArea, true);
  61 }
  62
  63
  64 status_t
  65 commpage_init(void)
  66 {
  67         // create a read/write kernel area
  68         sCommPageArea = create_area("kernel_commpage", (void **)&sCommPageAddress,
  69                 B_ANY_ADDRESS, COMMPAGE_SIZE, B_FULL_LOCK,
  70                 B_KERNEL_WRITE_AREA | B_KERNEL_READ_AREA);
  71
  72         // zero it out
  73         memset(sCommPageAddress, 0, COMMPAGE_SIZE);
  74
  75         // fill in some of the table
  76         sCommPageAddress[0] = COMMPAGE_SIGNATURE;
  77         sCommPageAddress[1] = COMMPAGE_VERSION;
  78
  79         // the next slot to allocate space is after the table
  80         sFreeCommPageSpace = ALIGN_ENTRY(&sCommPageAddress[COMMPAGE_TABLE_ENTRIES]);
  81
  82         // create the image for the commpage
  83         sCommPageImage = elf_create_memory_image("commpage", 0, COMMPAGE_SIZE, 0,
  84                 0);
  85         elf_add_memory_image_symbol(sCommPageImage, "commpage_table",
  86                 0, COMMPAGE_TABLE_ENTRIES * sizeof(addr_t),
  87                 B_SYMBOL_TYPE_DATA);
  88
  89         arch_commpage_init();
  90
  91         return B_OK;
  92 }
  93
  94
  95 status_t
  96 commpage_init_post_cpus(void)
  97 {
  98         return arch_commpage_init_post_cpus();
  99 }