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 | phys_addr_t ibft_phys_addr; |
35 | EXPORT_SYMBOL_GPL(ibft_phys_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 VGA_MEM 0xA0000 /* VGA buffer */ |
46 | #define VGA_SIZE 0x20000 /* 128kB */ |
47 | |
48 | /* |
49 | * Routine used to find and reserve the iSCSI Boot Format Table |
50 | */ |
51 | void __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 will |
61 | * only use ACPI for this |
62 | */ |
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(addr: virt, PAGE_SIZE); |
76 | virt = early_memremap_ro(phys_addr: pos, PAGE_SIZE); |
77 | virt_pos = pos; |
78 | } |
79 | |
80 | for (i = 0; i < ARRAY_SIZE(ibft_signs); i++) { |
81 | if (memcmp(p: virt + (pos - virt_pos), q: 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(base: 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 | |
98 | out: |
99 | early_memunmap(addr: virt, PAGE_SIZE); |
100 | } |
101 | |