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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright 2007-2010 Red Hat, Inc.4 * by Peter Jones <pjones@redhat.com>5 * Copyright 2007 IBM, Inc.6 * by Konrad Rzeszutek <konradr@linux.vnet.ibm.com>7 * Copyright 20088 * by Konrad Rzeszutek <ketuzsezr@darnok.org>9 *10 * This code finds the iSCSI Boot Format Table.11 */12 13#include <linux/memblock.h>14#include <linux/blkdev.h>15#include <linux/ctype.h>16#include <linux/device.h>17#include <linux/efi.h>18#include <linux/err.h>19#include <linux/init.h>20#include <linux/limits.h>21#include <linux/module.h>22#include <linux/pci.h>23#include <linux/stat.h>24#include <linux/string.h>25#include <linux/types.h>26#include <linux/acpi.h>27#include <linux/iscsi_ibft.h>28 29#include <asm/mmzone.h>30 31/*32 * Physical location of iSCSI Boot Format Table.33 */34phys_addr_t ibft_phys_addr;35EXPORT_SYMBOL_GPL(ibft_phys_addr);36 37static const struct {38 char *sign;39} ibft_signs[] = {40 { "iBFT" },41 { "BIFT" }, /* Broadcom iSCSI Offload */42};43 44#define IBFT_SIGN_LEN 445#define VGA_MEM 0xA0000 /* VGA buffer */46#define VGA_SIZE 0x20000 /* 128kB */47 48/*49 * Routine used to find and reserve the iSCSI Boot Format Table50 */51void __init reserve_ibft_region(void)52{53 unsigned long pos, virt_pos = 0;54 unsigned int len = 0;55 void *virt = NULL;56 int i;57 58 ibft_phys_addr = 0;59 60 /* iBFT 1.03 section 1.4.3.1 mandates that UEFI machines will61 * only use ACPI for this62 */63 if (efi_enabled(EFI_BOOT))64 return;65 66 for (pos = IBFT_START; pos < IBFT_END; pos += 16) {67 /* The table can't be inside the VGA BIOS reserved space,68 * so skip that area */69 if (pos == VGA_MEM)70 pos += VGA_SIZE;71 72 /* Map page by page */73 if (offset_in_page(pos) == 0) {74 if (virt)75 early_memunmap(virt, PAGE_SIZE);76 virt = early_memremap_ro(pos, PAGE_SIZE);77 virt_pos = pos;78 }79 80 for (i = 0; i < ARRAY_SIZE(ibft_signs); i++) {81 if (memcmp(virt + (pos - virt_pos), ibft_signs[i].sign,82 IBFT_SIGN_LEN) == 0) {83 unsigned long *addr =84 (unsigned long *)(virt + pos - virt_pos + 4);85 len = *addr;86 /* if the length of the table extends past 1M,87 * the table cannot be valid. */88 if (pos + len <= (IBFT_END-1)) {89 ibft_phys_addr = pos;90 memblock_reserve(ibft_phys_addr, PAGE_ALIGN(len));91 pr_info("iBFT found at %pa.\n", &ibft_phys_addr);92 goto out;93 }94 }95 }96 }97 98out:99 early_memunmap(virt, PAGE_SIZE);100}101