1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 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 2008 8 * 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 */ 34 struct acpi_table_ibft *ibft_addr; 35 EXPORT_SYMBOL_GPL(ibft_addr); 36 37 static const struct { 38 char *sign; 39 } ibft_signs[] = { 40 { "iBFT" }, 41 { "BIFT" }, /* Broadcom iSCSI Offload */ 42 }; 43 44 #define IBFT_SIGN_LEN 4 45 #define IBFT_START 0x80000 /* 512kB */ 46 #define IBFT_END 0x100000 /* 1MB */ 47 #define VGA_MEM 0xA0000 /* VGA buffer */ 48 #define VGA_SIZE 0x20000 /* 128kB */ 49 50 static int __init find_ibft_in_mem(void) 51 { 52 unsigned long pos; 53 unsigned int len = 0; 54 void *virt; 55 int i; 56 57 for (pos = IBFT_START; pos < IBFT_END; pos += 16) { 58 /* The table can't be inside the VGA BIOS reserved space, 59 * so skip that area */ 60 if (pos == VGA_MEM) 61 pos += VGA_SIZE; 62 virt = isa_bus_to_virt(pos); 63 64 for (i = 0; i < ARRAY_SIZE(ibft_signs); i++) { 65 if (memcmp(virt, ibft_signs[i].sign, IBFT_SIGN_LEN) == 66 0) { 67 unsigned long *addr = 68 (unsigned long *)isa_bus_to_virt(pos + 4); 69 len = *addr; 70 /* if the length of the table extends past 1M, 71 * the table cannot be valid. */ 72 if (pos + len <= (IBFT_END-1)) { 73 ibft_addr = (struct acpi_table_ibft *)virt; 74 pr_info("iBFT found at 0x%lx.\n", pos); 75 goto done; 76 } 77 } 78 } 79 } 80 done: 81 return len; 82 } 83 /* 84 * Routine used to find the iSCSI Boot Format Table. The logical 85 * kernel address is set in the ibft_addr global variable. 86 */ 87 unsigned long __init find_ibft_region(unsigned long *sizep) 88 { 89 ibft_addr = NULL; 90 91 /* iBFT 1.03 section 1.4.3.1 mandates that UEFI machines will 92 * only use ACPI for this */ 93 94 if (!efi_enabled(EFI_BOOT)) 95 find_ibft_in_mem(); 96 97 if (ibft_addr) { 98 *sizep = PAGE_ALIGN(ibft_addr->header.length); 99 return (u64)virt_to_phys(ibft_addr); 100 } 101 102 *sizep = 0; 103 return 0; 104 } 105