2019-01-23 11:08:45 +00:00
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// SPDX-License-Identifier: GPL-2.0
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#define BOOT_CTYPE_H
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#include "misc.h"
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#include "error.h"
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#include "../string.h"
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2019-01-23 11:08:46 +00:00
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#include <linux/efi.h>
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#include <asm/efi.h>
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2019-01-23 11:08:45 +00:00
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/*
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* Max length of 64-bit hex address string is 19, prefix "0x" + 16 hex
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* digits, and '\0' for termination.
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*/
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#define MAX_ADDR_LEN 19
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static acpi_physical_address get_acpi_rsdp(void)
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{
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acpi_physical_address addr = 0;
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#ifdef CONFIG_KEXEC
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char val[MAX_ADDR_LEN] = { };
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int ret;
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ret = cmdline_find_option("acpi_rsdp", val, MAX_ADDR_LEN);
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if (ret < 0)
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return 0;
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if (kstrtoull(val, 16, &addr))
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return 0;
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#endif
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return addr;
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}
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2019-01-23 11:08:46 +00:00
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/* Search EFI system tables for RSDP. */
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static acpi_physical_address efi_get_rsdp_addr(void)
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{
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acpi_physical_address rsdp_addr = 0;
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#ifdef CONFIG_EFI
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efi_system_table_t *systab;
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struct efi_info *ei;
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bool efi_64;
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int size, i;
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char *sig;
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ei = &boot_params->efi_info;
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sig = (char *)&ei->efi_loader_signature;
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if (!strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) {
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efi_64 = true;
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} else if (!strncmp(sig, EFI32_LOADER_SIGNATURE, 4)) {
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efi_64 = false;
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} else {
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debug_putstr("Wrong EFI loader signature.\n");
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return 0;
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}
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/* Get systab from boot params. */
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#ifdef CONFIG_X86_64
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systab = (efi_system_table_t *)(ei->efi_systab | ((__u64)ei->efi_systab_hi<<32));
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#else
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if (ei->efi_systab_hi || ei->efi_memmap_hi) {
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debug_putstr("Error getting RSDP address: EFI system table located above 4GB.\n");
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return 0;
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}
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systab = (efi_system_table_t *)ei->efi_systab;
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#endif
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if (!systab)
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error("EFI system table not found.");
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/*
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* Get EFI tables from systab.
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*/
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size = efi_64 ? sizeof(efi_config_table_64_t) :
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sizeof(efi_config_table_32_t);
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for (i = 0; i < systab->nr_tables; i++) {
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acpi_physical_address table;
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void *config_tables;
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efi_guid_t guid;
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config_tables = (void *)(systab->tables + size * i);
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if (efi_64) {
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efi_config_table_64_t *tmp_table;
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tmp_table = config_tables;
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guid = tmp_table->guid;
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table = tmp_table->table;
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if (!IS_ENABLED(CONFIG_X86_64) && table >> 32) {
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debug_putstr("Error getting RSDP address: EFI config table located above 4GB.\n");
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return 0;
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}
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} else {
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efi_config_table_32_t *tmp_table;
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tmp_table = config_tables;
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guid = tmp_table->guid;
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table = tmp_table->table;
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}
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if (!(efi_guidcmp(guid, ACPI_TABLE_GUID)))
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rsdp_addr = table;
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else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID)))
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return table;
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}
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#endif
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return rsdp_addr;
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}
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2019-01-23 11:08:47 +00:00
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static u8 compute_checksum(u8 *buffer, u32 length)
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{
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u8 *end = buffer + length;
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u8 sum = 0;
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while (buffer < end)
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sum += *(buffer++);
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return sum;
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}
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/* Search a block of memory for the RSDP signature. */
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static u8 *scan_mem_for_rsdp(u8 *start, u32 length)
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{
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struct acpi_table_rsdp *rsdp;
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u8 *address, *end;
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end = start + length;
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/* Search from given start address for the requested length */
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for (address = start; address < end; address += ACPI_RSDP_SCAN_STEP) {
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/*
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* Both RSDP signature and checksum must be correct.
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* Note: Sometimes there exists more than one RSDP in memory;
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* the valid RSDP has a valid checksum, all others have an
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* invalid checksum.
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*/
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rsdp = (struct acpi_table_rsdp *)address;
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/* BAD Signature */
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if (!ACPI_VALIDATE_RSDP_SIG(rsdp->signature))
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continue;
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/* Check the standard checksum */
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if (compute_checksum((u8 *)rsdp, ACPI_RSDP_CHECKSUM_LENGTH))
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continue;
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/* Check extended checksum if table version >= 2 */
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if ((rsdp->revision >= 2) &&
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(compute_checksum((u8 *)rsdp, ACPI_RSDP_XCHECKSUM_LENGTH)))
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continue;
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/* Signature and checksum valid, we have found a real RSDP */
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return address;
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}
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return NULL;
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}
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/* Search RSDP address in EBDA. */
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static acpi_physical_address bios_get_rsdp_addr(void)
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{
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unsigned long address;
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u8 *rsdp;
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/* Get the location of the Extended BIOS Data Area (EBDA) */
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address = *(u16 *)ACPI_EBDA_PTR_LOCATION;
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address <<= 4;
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/*
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* Search EBDA paragraphs (EBDA is required to be a minimum of
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* 1K length)
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*/
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if (address > 0x400) {
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rsdp = scan_mem_for_rsdp((u8 *)address, ACPI_EBDA_WINDOW_SIZE);
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if (rsdp)
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return (acpi_physical_address)(unsigned long)rsdp;
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}
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/* Search upper memory: 16-byte boundaries in E0000h-FFFFFh */
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rsdp = scan_mem_for_rsdp((u8 *) ACPI_HI_RSDP_WINDOW_BASE,
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ACPI_HI_RSDP_WINDOW_SIZE);
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if (rsdp)
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return (acpi_physical_address)(unsigned long)rsdp;
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return 0;
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}
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