xref: /openbmc/linux/drivers/soc/qcom/mdt_loader.c (revision 2f190ac2)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Qualcomm Peripheral Image Loader
4  *
5  * Copyright (C) 2016 Linaro Ltd
6  * Copyright (C) 2015 Sony Mobile Communications Inc
7  * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
8  */
9 
10 #include <linux/device.h>
11 #include <linux/elf.h>
12 #include <linux/firmware.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/qcom_scm.h>
16 #include <linux/sizes.h>
17 #include <linux/slab.h>
18 #include <linux/soc/qcom/mdt_loader.h>
19 
20 static bool mdt_phdr_valid(const struct elf32_phdr *phdr)
21 {
22 	if (phdr->p_type != PT_LOAD)
23 		return false;
24 
25 	if ((phdr->p_flags & QCOM_MDT_TYPE_MASK) == QCOM_MDT_TYPE_HASH)
26 		return false;
27 
28 	if (!phdr->p_memsz)
29 		return false;
30 
31 	return true;
32 }
33 
34 static ssize_t mdt_load_split_segment(void *ptr, const struct elf32_phdr *phdrs,
35 				      unsigned int segment, const char *fw_name,
36 				      struct device *dev)
37 {
38 	const struct elf32_phdr *phdr = &phdrs[segment];
39 	const struct firmware *seg_fw;
40 	char *seg_name;
41 	ssize_t ret;
42 
43 	if (strlen(fw_name) < 4)
44 		return -EINVAL;
45 
46 	seg_name = kstrdup(fw_name, GFP_KERNEL);
47 	if (!seg_name)
48 		return -ENOMEM;
49 
50 	sprintf(seg_name + strlen(fw_name) - 3, "b%02d", segment);
51 	ret = request_firmware_into_buf(&seg_fw, seg_name, dev,
52 					ptr, phdr->p_filesz);
53 	if (ret) {
54 		dev_err(dev, "error %zd loading %s\n", ret, seg_name);
55 		kfree(seg_name);
56 		return ret;
57 	}
58 
59 	if (seg_fw->size != phdr->p_filesz) {
60 		dev_err(dev,
61 			"failed to load segment %d from truncated file %s\n",
62 			segment, seg_name);
63 		ret = -EINVAL;
64 	}
65 
66 	release_firmware(seg_fw);
67 	kfree(seg_name);
68 
69 	return ret;
70 }
71 
72 /**
73  * qcom_mdt_get_size() - acquire size of the memory region needed to load mdt
74  * @fw:		firmware object for the mdt file
75  *
76  * Returns size of the loaded firmware blob, or -EINVAL on failure.
77  */
78 ssize_t qcom_mdt_get_size(const struct firmware *fw)
79 {
80 	const struct elf32_phdr *phdrs;
81 	const struct elf32_phdr *phdr;
82 	const struct elf32_hdr *ehdr;
83 	phys_addr_t min_addr = PHYS_ADDR_MAX;
84 	phys_addr_t max_addr = 0;
85 	int i;
86 
87 	ehdr = (struct elf32_hdr *)fw->data;
88 	phdrs = (struct elf32_phdr *)(ehdr + 1);
89 
90 	for (i = 0; i < ehdr->e_phnum; i++) {
91 		phdr = &phdrs[i];
92 
93 		if (!mdt_phdr_valid(phdr))
94 			continue;
95 
96 		if (phdr->p_paddr < min_addr)
97 			min_addr = phdr->p_paddr;
98 
99 		if (phdr->p_paddr + phdr->p_memsz > max_addr)
100 			max_addr = ALIGN(phdr->p_paddr + phdr->p_memsz, SZ_4K);
101 	}
102 
103 	return min_addr < max_addr ? max_addr - min_addr : -EINVAL;
104 }
105 EXPORT_SYMBOL_GPL(qcom_mdt_get_size);
106 
107 /**
108  * qcom_mdt_read_metadata() - read header and metadata from mdt or mbn
109  * @fw:		firmware of mdt header or mbn
110  * @data_len:	length of the read metadata blob
111  * @fw_name:	name of the firmware, for construction of segment file names
112  * @dev:	device handle to associate resources with
113  *
114  * The mechanism that performs the authentication of the loading firmware
115  * expects an ELF header directly followed by the segment of hashes, with no
116  * padding inbetween. This function allocates a chunk of memory for this pair
117  * and copy the two pieces into the buffer.
118  *
119  * In the case of split firmware the hash is found directly following the ELF
120  * header, rather than at p_offset described by the second program header.
121  *
122  * The caller is responsible to free (kfree()) the returned pointer.
123  *
124  * Return: pointer to data, or ERR_PTR()
125  */
126 void *qcom_mdt_read_metadata(const struct firmware *fw, size_t *data_len,
127 			     const char *fw_name, struct device *dev)
128 {
129 	const struct elf32_phdr *phdrs;
130 	const struct elf32_hdr *ehdr;
131 	unsigned int hash_segment = 0;
132 	size_t hash_offset;
133 	size_t hash_size;
134 	size_t ehdr_size;
135 	unsigned int i;
136 	ssize_t ret;
137 	void *data;
138 
139 	ehdr = (struct elf32_hdr *)fw->data;
140 	phdrs = (struct elf32_phdr *)(ehdr + 1);
141 
142 	if (ehdr->e_phnum < 2)
143 		return ERR_PTR(-EINVAL);
144 
145 	if (phdrs[0].p_type == PT_LOAD)
146 		return ERR_PTR(-EINVAL);
147 
148 	for (i = 1; i < ehdr->e_phnum; i++) {
149 		if ((phdrs[i].p_flags & QCOM_MDT_TYPE_MASK) == QCOM_MDT_TYPE_HASH) {
150 			hash_segment = i;
151 			break;
152 		}
153 	}
154 
155 	if (!hash_segment) {
156 		dev_err(dev, "no hash segment found in %s\n", fw_name);
157 		return ERR_PTR(-EINVAL);
158 	}
159 
160 	ehdr_size = phdrs[0].p_filesz;
161 	hash_size = phdrs[hash_segment].p_filesz;
162 
163 	data = kmalloc(ehdr_size + hash_size, GFP_KERNEL);
164 	if (!data)
165 		return ERR_PTR(-ENOMEM);
166 
167 	/* Copy ELF header */
168 	memcpy(data, fw->data, ehdr_size);
169 
170 	if (ehdr_size + hash_size == fw->size) {
171 		/* Firmware is split and hash is packed following the ELF header */
172 		hash_offset = phdrs[0].p_filesz;
173 		memcpy(data + ehdr_size, fw->data + hash_offset, hash_size);
174 	} else if (phdrs[hash_segment].p_offset + hash_size <= fw->size) {
175 		/* Hash is in its own segment, but within the loaded file */
176 		hash_offset = phdrs[hash_segment].p_offset;
177 		memcpy(data + ehdr_size, fw->data + hash_offset, hash_size);
178 	} else {
179 		/* Hash is in its own segment, beyond the loaded file */
180 		ret = mdt_load_split_segment(data + ehdr_size, phdrs, hash_segment, fw_name, dev);
181 		if (ret) {
182 			kfree(data);
183 			return ERR_PTR(ret);
184 		}
185 	}
186 
187 	*data_len = ehdr_size + hash_size;
188 
189 	return data;
190 }
191 EXPORT_SYMBOL_GPL(qcom_mdt_read_metadata);
192 
193 /**
194  * qcom_mdt_pas_init() - initialize PAS region for firmware loading
195  * @dev:	device handle to associate resources with
196  * @fw:		firmware object for the mdt file
197  * @fw_name:	name of the firmware, for construction of segment file names
198  * @pas_id:	PAS identifier
199  * @mem_phys:	physical address of allocated memory region
200  * @ctx:	PAS metadata context, to be released by caller
201  *
202  * Returns 0 on success, negative errno otherwise.
203  */
204 int qcom_mdt_pas_init(struct device *dev, const struct firmware *fw,
205 		      const char *fw_name, int pas_id, phys_addr_t mem_phys,
206 		      struct qcom_scm_pas_metadata *ctx)
207 {
208 	const struct elf32_phdr *phdrs;
209 	const struct elf32_phdr *phdr;
210 	const struct elf32_hdr *ehdr;
211 	phys_addr_t min_addr = PHYS_ADDR_MAX;
212 	phys_addr_t max_addr = 0;
213 	size_t metadata_len;
214 	void *metadata;
215 	int ret;
216 	int i;
217 
218 	ehdr = (struct elf32_hdr *)fw->data;
219 	phdrs = (struct elf32_phdr *)(ehdr + 1);
220 
221 	for (i = 0; i < ehdr->e_phnum; i++) {
222 		phdr = &phdrs[i];
223 
224 		if (!mdt_phdr_valid(phdr))
225 			continue;
226 
227 		if (phdr->p_paddr < min_addr)
228 			min_addr = phdr->p_paddr;
229 
230 		if (phdr->p_paddr + phdr->p_memsz > max_addr)
231 			max_addr = ALIGN(phdr->p_paddr + phdr->p_memsz, SZ_4K);
232 	}
233 
234 	metadata = qcom_mdt_read_metadata(fw, &metadata_len, fw_name, dev);
235 	if (IS_ERR(metadata)) {
236 		ret = PTR_ERR(metadata);
237 		dev_err(dev, "error %d reading firmware %s metadata\n", ret, fw_name);
238 		goto out;
239 	}
240 
241 	ret = qcom_scm_pas_init_image(pas_id, metadata, metadata_len, ctx);
242 	kfree(metadata);
243 	if (ret) {
244 		/* Invalid firmware metadata */
245 		dev_err(dev, "error %d initializing firmware %s\n", ret, fw_name);
246 		goto out;
247 	}
248 
249 	ret = qcom_scm_pas_mem_setup(pas_id, mem_phys, max_addr - min_addr);
250 	if (ret) {
251 		/* Unable to set up relocation */
252 		dev_err(dev, "error %d setting up firmware %s\n", ret, fw_name);
253 		goto out;
254 	}
255 
256 out:
257 	return ret;
258 }
259 EXPORT_SYMBOL_GPL(qcom_mdt_pas_init);
260 
261 static int __qcom_mdt_load(struct device *dev, const struct firmware *fw,
262 			   const char *fw_name, int pas_id, void *mem_region,
263 			   phys_addr_t mem_phys, size_t mem_size,
264 			   phys_addr_t *reloc_base, bool pas_init)
265 {
266 	const struct elf32_phdr *phdrs;
267 	const struct elf32_phdr *phdr;
268 	const struct elf32_hdr *ehdr;
269 	phys_addr_t mem_reloc;
270 	phys_addr_t min_addr = PHYS_ADDR_MAX;
271 	ssize_t offset;
272 	bool relocate = false;
273 	void *ptr;
274 	int ret = 0;
275 	int i;
276 
277 	if (!fw || !mem_region || !mem_phys || !mem_size)
278 		return -EINVAL;
279 
280 	ehdr = (struct elf32_hdr *)fw->data;
281 	phdrs = (struct elf32_phdr *)(ehdr + 1);
282 
283 	for (i = 0; i < ehdr->e_phnum; i++) {
284 		phdr = &phdrs[i];
285 
286 		if (!mdt_phdr_valid(phdr))
287 			continue;
288 
289 		if (phdr->p_flags & QCOM_MDT_RELOCATABLE)
290 			relocate = true;
291 
292 		if (phdr->p_paddr < min_addr)
293 			min_addr = phdr->p_paddr;
294 	}
295 
296 	if (relocate) {
297 		/*
298 		 * The image is relocatable, so offset each segment based on
299 		 * the lowest segment address.
300 		 */
301 		mem_reloc = min_addr;
302 	} else {
303 		/*
304 		 * Image is not relocatable, so offset each segment based on
305 		 * the allocated physical chunk of memory.
306 		 */
307 		mem_reloc = mem_phys;
308 	}
309 
310 	for (i = 0; i < ehdr->e_phnum; i++) {
311 		phdr = &phdrs[i];
312 
313 		if (!mdt_phdr_valid(phdr))
314 			continue;
315 
316 		offset = phdr->p_paddr - mem_reloc;
317 		if (offset < 0 || offset + phdr->p_memsz > mem_size) {
318 			dev_err(dev, "segment outside memory range\n");
319 			ret = -EINVAL;
320 			break;
321 		}
322 
323 		if (phdr->p_filesz > phdr->p_memsz) {
324 			dev_err(dev,
325 				"refusing to load segment %d with p_filesz > p_memsz\n",
326 				i);
327 			ret = -EINVAL;
328 			break;
329 		}
330 
331 		ptr = mem_region + offset;
332 
333 		if (phdr->p_filesz && phdr->p_offset < fw->size &&
334 		    phdr->p_offset + phdr->p_filesz <= fw->size) {
335 			/* Firmware is large enough to be non-split */
336 			if (phdr->p_offset + phdr->p_filesz > fw->size) {
337 				dev_err(dev, "file %s segment %d would be truncated\n",
338 					fw_name, i);
339 				ret = -EINVAL;
340 				break;
341 			}
342 
343 			memcpy(ptr, fw->data + phdr->p_offset, phdr->p_filesz);
344 		} else if (phdr->p_filesz) {
345 			/* Firmware not large enough, load split-out segments */
346 			ret = mdt_load_split_segment(ptr, phdrs, i, fw_name, dev);
347 			if (ret)
348 				break;
349 		}
350 
351 		if (phdr->p_memsz > phdr->p_filesz)
352 			memset(ptr + phdr->p_filesz, 0, phdr->p_memsz - phdr->p_filesz);
353 	}
354 
355 	if (reloc_base)
356 		*reloc_base = mem_reloc;
357 
358 	return ret;
359 }
360 
361 /**
362  * qcom_mdt_load() - load the firmware which header is loaded as fw
363  * @dev:	device handle to associate resources with
364  * @fw:		firmware object for the mdt file
365  * @firmware:	name of the firmware, for construction of segment file names
366  * @pas_id:	PAS identifier
367  * @mem_region:	allocated memory region to load firmware into
368  * @mem_phys:	physical address of allocated memory region
369  * @mem_size:	size of the allocated memory region
370  * @reloc_base:	adjusted physical address after relocation
371  *
372  * Returns 0 on success, negative errno otherwise.
373  */
374 int qcom_mdt_load(struct device *dev, const struct firmware *fw,
375 		  const char *firmware, int pas_id, void *mem_region,
376 		  phys_addr_t mem_phys, size_t mem_size,
377 		  phys_addr_t *reloc_base)
378 {
379 	int ret;
380 
381 	ret = qcom_mdt_pas_init(dev, fw, firmware, pas_id, mem_phys, NULL);
382 	if (ret)
383 		return ret;
384 
385 	return __qcom_mdt_load(dev, fw, firmware, pas_id, mem_region, mem_phys,
386 			       mem_size, reloc_base, true);
387 }
388 EXPORT_SYMBOL_GPL(qcom_mdt_load);
389 
390 /**
391  * qcom_mdt_load_no_init() - load the firmware which header is loaded as fw
392  * @dev:	device handle to associate resources with
393  * @fw:		firmware object for the mdt file
394  * @firmware:	name of the firmware, for construction of segment file names
395  * @pas_id:	PAS identifier
396  * @mem_region:	allocated memory region to load firmware into
397  * @mem_phys:	physical address of allocated memory region
398  * @mem_size:	size of the allocated memory region
399  * @reloc_base:	adjusted physical address after relocation
400  *
401  * Returns 0 on success, negative errno otherwise.
402  */
403 int qcom_mdt_load_no_init(struct device *dev, const struct firmware *fw,
404 			  const char *firmware, int pas_id,
405 			  void *mem_region, phys_addr_t mem_phys,
406 			  size_t mem_size, phys_addr_t *reloc_base)
407 {
408 	return __qcom_mdt_load(dev, fw, firmware, pas_id, mem_region, mem_phys,
409 			       mem_size, reloc_base, false);
410 }
411 EXPORT_SYMBOL_GPL(qcom_mdt_load_no_init);
412 
413 MODULE_DESCRIPTION("Firmware parser for Qualcomm MDT format");
414 MODULE_LICENSE("GPL v2");
415