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 - 2025, 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
 18ACPI_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 ******************************************************************************/
 40static 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
 63void *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
109void 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}