1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/sched.h>
3 #include <linux/mm.h>
4 #include <linux/uaccess.h>
5 #include <linux/mmzone.h>
6 #include <linux/ioport.h>
7 #include <linux/seq_file.h>
8 #include <linux/console.h>
9 #include <linux/init.h>
10 #include <linux/edd.h>
11 #include <linux/dmi.h>
12 #include <linux/pfn.h>
13 #include <linux/pci.h>
14 #include <linux/export.h>
15 
16 #include <asm/probe_roms.h>
17 #include <asm/pci-direct.h>
18 #include <asm/e820/api.h>
19 #include <asm/mmzone.h>
20 #include <asm/setup.h>
21 #include <asm/sections.h>
22 #include <asm/io.h>
23 #include <asm/setup_arch.h>
24 #include <asm/sev.h>
25 
26 static struct resource system_rom_resource = {
27 	.name	= "System ROM",
28 	.start	= 0xf0000,
29 	.end	= 0xfffff,
30 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
31 };
32 
33 static struct resource extension_rom_resource = {
34 	.name	= "Extension ROM",
35 	.start	= 0xe0000,
36 	.end	= 0xeffff,
37 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
38 };
39 
40 static struct resource adapter_rom_resources[] = { {
41 	.name 	= "Adapter ROM",
42 	.start	= 0xc8000,
43 	.end	= 0,
44 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
45 }, {
46 	.name 	= "Adapter ROM",
47 	.start	= 0,
48 	.end	= 0,
49 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
50 }, {
51 	.name 	= "Adapter ROM",
52 	.start	= 0,
53 	.end	= 0,
54 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
55 }, {
56 	.name 	= "Adapter ROM",
57 	.start	= 0,
58 	.end	= 0,
59 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
60 }, {
61 	.name 	= "Adapter ROM",
62 	.start	= 0,
63 	.end	= 0,
64 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
65 }, {
66 	.name 	= "Adapter ROM",
67 	.start	= 0,
68 	.end	= 0,
69 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
70 } };
71 
72 static struct resource video_rom_resource = {
73 	.name 	= "Video ROM",
74 	.start	= 0xc0000,
75 	.end	= 0xc7fff,
76 	.flags	= IORESOURCE_BUSY | IORESOURCE_READONLY | IORESOURCE_MEM
77 };
78 
79 /* does this oprom support the given pci device, or any of the devices
80  * that the driver supports?
81  */
match_id(struct pci_dev * pdev,unsigned short vendor,unsigned short device)82 static bool match_id(struct pci_dev *pdev, unsigned short vendor, unsigned short device)
83 {
84 	struct pci_driver *drv = to_pci_driver(pdev->dev.driver);
85 	const struct pci_device_id *id;
86 
87 	if (pdev->vendor == vendor && pdev->device == device)
88 		return true;
89 
90 	for (id = drv ? drv->id_table : NULL; id && id->vendor; id++)
91 		if (id->vendor == vendor && id->device == device)
92 			break;
93 
94 	return id && id->vendor;
95 }
96 
probe_list(struct pci_dev * pdev,unsigned short vendor,const void * rom_list)97 static bool probe_list(struct pci_dev *pdev, unsigned short vendor,
98 		       const void *rom_list)
99 {
100 	unsigned short device;
101 
102 	do {
103 		if (get_kernel_nofault(device, rom_list) != 0)
104 			device = 0;
105 
106 		if (device && match_id(pdev, vendor, device))
107 			break;
108 
109 		rom_list += 2;
110 	} while (device);
111 
112 	return !!device;
113 }
114 
find_oprom(struct pci_dev * pdev)115 static struct resource *find_oprom(struct pci_dev *pdev)
116 {
117 	struct resource *oprom = NULL;
118 	int i;
119 
120 	for (i = 0; i < ARRAY_SIZE(adapter_rom_resources); i++) {
121 		struct resource *res = &adapter_rom_resources[i];
122 		unsigned short offset, vendor, device, list, rev;
123 		const void *rom;
124 
125 		if (res->end == 0)
126 			break;
127 
128 		rom = isa_bus_to_virt(res->start);
129 		if (get_kernel_nofault(offset, rom + 0x18) != 0)
130 			continue;
131 
132 		if (get_kernel_nofault(vendor, rom + offset + 0x4) != 0)
133 			continue;
134 
135 		if (get_kernel_nofault(device, rom + offset + 0x6) != 0)
136 			continue;
137 
138 		if (match_id(pdev, vendor, device)) {
139 			oprom = res;
140 			break;
141 		}
142 
143 		if (get_kernel_nofault(list, rom + offset + 0x8) == 0 &&
144 		    get_kernel_nofault(rev, rom + offset + 0xc) == 0 &&
145 		    rev >= 3 && list &&
146 		    probe_list(pdev, vendor, rom + offset + list)) {
147 			oprom = res;
148 			break;
149 		}
150 	}
151 
152 	return oprom;
153 }
154 
pci_map_biosrom(struct pci_dev * pdev)155 void __iomem *pci_map_biosrom(struct pci_dev *pdev)
156 {
157 	struct resource *oprom = find_oprom(pdev);
158 
159 	if (!oprom)
160 		return NULL;
161 
162 	return ioremap(oprom->start, resource_size(oprom));
163 }
164 EXPORT_SYMBOL(pci_map_biosrom);
165 
pci_unmap_biosrom(void __iomem * image)166 void pci_unmap_biosrom(void __iomem *image)
167 {
168 	iounmap(image);
169 }
170 EXPORT_SYMBOL(pci_unmap_biosrom);
171 
pci_biosrom_size(struct pci_dev * pdev)172 size_t pci_biosrom_size(struct pci_dev *pdev)
173 {
174 	struct resource *oprom = find_oprom(pdev);
175 
176 	return oprom ? resource_size(oprom) : 0;
177 }
178 EXPORT_SYMBOL(pci_biosrom_size);
179 
180 #define ROMSIGNATURE 0xaa55
181 
romsignature(const unsigned char * rom)182 static int __init romsignature(const unsigned char *rom)
183 {
184 	const unsigned short * const ptr = (const unsigned short *)rom;
185 	unsigned short sig;
186 
187 	return get_kernel_nofault(sig, ptr) == 0 && sig == ROMSIGNATURE;
188 }
189 
romchecksum(const unsigned char * rom,unsigned long length)190 static int __init romchecksum(const unsigned char *rom, unsigned long length)
191 {
192 	unsigned char sum, c;
193 
194 	for (sum = 0; length && get_kernel_nofault(c, rom++) == 0; length--)
195 		sum += c;
196 	return !length && !sum;
197 }
198 
probe_roms(void)199 void __init probe_roms(void)
200 {
201 	unsigned long start, length, upper;
202 	const unsigned char *rom;
203 	unsigned char c;
204 	int i;
205 
206 	/*
207 	 * The ROM memory range is not part of the e820 table and is therefore not
208 	 * pre-validated by BIOS. The kernel page table maps the ROM region as encrypted
209 	 * memory, and SNP requires encrypted memory to be validated before access.
210 	 * Do that here.
211 	 */
212 	snp_prep_memory(video_rom_resource.start,
213 			((system_rom_resource.end + 1) - video_rom_resource.start),
214 			SNP_PAGE_STATE_PRIVATE);
215 
216 	/* video rom */
217 	upper = adapter_rom_resources[0].start;
218 	for (start = video_rom_resource.start; start < upper; start += 2048) {
219 		rom = isa_bus_to_virt(start);
220 		if (!romsignature(rom))
221 			continue;
222 
223 		video_rom_resource.start = start;
224 
225 		if (get_kernel_nofault(c, rom + 2) != 0)
226 			continue;
227 
228 		/* 0 < length <= 0x7f * 512, historically */
229 		length = c * 512;
230 
231 		/* if checksum okay, trust length byte */
232 		if (length && romchecksum(rom, length))
233 			video_rom_resource.end = start + length - 1;
234 
235 		request_resource(&iomem_resource, &video_rom_resource);
236 		break;
237 	}
238 
239 	start = (video_rom_resource.end + 1 + 2047) & ~2047UL;
240 	if (start < upper)
241 		start = upper;
242 
243 	/* system rom */
244 	request_resource(&iomem_resource, &system_rom_resource);
245 	upper = system_rom_resource.start;
246 
247 	/* check for extension rom (ignore length byte!) */
248 	rom = isa_bus_to_virt(extension_rom_resource.start);
249 	if (romsignature(rom)) {
250 		length = resource_size(&extension_rom_resource);
251 		if (romchecksum(rom, length)) {
252 			request_resource(&iomem_resource, &extension_rom_resource);
253 			upper = extension_rom_resource.start;
254 		}
255 	}
256 
257 	/* check for adapter roms on 2k boundaries */
258 	for (i = 0; i < ARRAY_SIZE(adapter_rom_resources) && start < upper; start += 2048) {
259 		rom = isa_bus_to_virt(start);
260 		if (!romsignature(rom))
261 			continue;
262 
263 		if (get_kernel_nofault(c, rom + 2) != 0)
264 			continue;
265 
266 		/* 0 < length <= 0x7f * 512, historically */
267 		length = c * 512;
268 
269 		/* but accept any length that fits if checksum okay */
270 		if (!length || start + length > upper || !romchecksum(rom, length))
271 			continue;
272 
273 		adapter_rom_resources[i].start = start;
274 		adapter_rom_resources[i].end = start + length - 1;
275 		request_resource(&iomem_resource, &adapter_rom_resources[i]);
276 
277 		start = adapter_rom_resources[i++].end & ~2047UL;
278 	}
279 }
280 
281