tools/power/acpi/os_specific/service_layers/osunixmap.c

   1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
   2 /******************************************************************************
   3  *
   4  * Module Name: osunixmap - Unix OSL for file mappings
   5  *
   6  * Copyright (C) 2000 - 2020, Intel Corp.
   7  *
   8  *****************************************************************************/
   9
  10 #include "acpidump.h"
  11 #include <unistd.h>
  12 #include <sys/mman.h>
  13 #ifdef _free_BSD
  14 #include <sys/param.h>
  15 #endif
  16
  17 #define _COMPONENT          ACPI_OS_SERVICES
  18 ACPI_MODULE_NAME("osunixmap")
  19
  20 #ifndef O_BINARY
  21 #define O_BINARY 0
  22 #endif
  23 #if defined(_dragon_fly) || defined(_free_BSD) || defined(_QNX)
  24 #define MMAP_FLAGS          MAP_SHARED
  25 #else
  26 #define MMAP_FLAGS          MAP_PRIVATE
  27 #endif
  28 #define SYSTEM_MEMORY       "/dev/mem"
  29 /*******************************************************************************
  30  *
  31  * FUNCTION:    acpi_os_get_page_size
  32  *
  33  * PARAMETERS:  None
  34  *
  35  * RETURN:      Page size of the platform.
  36  *
  37  * DESCRIPTION: Obtain page size of the platform.
  38  *
  39  ******************************************************************************/
  40 static acpi_size acpi_os_get_page_size(void)
  41 {
  42
  43 #ifdef PAGE_SIZE
  44         return PAGE_SIZE;
  45 #else
  46         return sysconf(_SC_PAGESIZE);
  47 #endif
  48 }
  49
  50 /******************************************************************************
  51  *
  52  * FUNCTION:    acpi_os_map_memory
  53  *
  54  * PARAMETERS:  where               - Physical address of memory to be mapped
  55  *              length              - How much memory to map
  56  *
  57  * RETURN:      Pointer to mapped memory. Null on error.
  58  *
  59  * DESCRIPTION: Map physical memory into local address space.
  60  *
  61  *****************************************************************************/
  62
  63 void *acpi_os_map_memory(acpi_physical_address where, acpi_size length)
  64 {
  65         u8 *mapped_memory;
  66         acpi_physical_address offset;
  67         acpi_size page_size;
  68         int fd;
  69
  70         fd = open(SYSTEM_MEMORY, O_RDONLY | O_BINARY);
  71         if (fd < 0) {
  72                 fprintf(stderr, "Cannot open %s\n", SYSTEM_MEMORY);
  73                 return (NULL);
  74         }
  75
  76         /* Align the offset to use mmap */
  77
  78         page_size = acpi_os_get_page_size();
  79         offset = where % page_size;
  80
  81         /* Map the table header to get the length of the full table */
  82
  83         mapped_memory = mmap(NULL, (length + offset), PROT_READ, MMAP_FLAGS,
  84                              fd, (where - offset));
  85         if (mapped_memory == MAP_FAILED) {
  86                 fprintf(stderr, "Cannot map %s\n", SYSTEM_MEMORY);
  87                 close(fd);
  88                 return (NULL);
  89         }
  90
  91         close(fd);
  92         return (ACPI_CAST8(mapped_memory + offset));
  93 }
  94
  95 /******************************************************************************
  96  *
  97  * FUNCTION:    acpi_os_unmap_memory
  98  *
  99  * PARAMETERS:  where               - Logical address of memory to be unmapped
 100  *              length              - How much memory to unmap
 101  *
 102  * RETURN:      None.
 103  *
 104  * DESCRIPTION: Delete a previously created mapping. Where and Length must
 105  *              correspond to a previous mapping exactly.
 106  *
 107  *****************************************************************************/
 108
 109 void acpi_os_unmap_memory(void *where, acpi_size length)
 110 {
 111         acpi_physical_address offset;
 112         acpi_size page_size;
 113
 114         page_size = acpi_os_get_page_size();
 115         offset = ACPI_TO_INTEGER(where) % page_size;
 116         munmap((u8 *)where - offset, (length + offset));
 117 }