xref: /openbmc/linux/drivers/soc/qcom/mdt_loader.c (revision 078b39c9)
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/firmware/qcom/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 	bool relocate = false;
214 	size_t metadata_len;
215 	void *metadata;
216 	int ret;
217 	int i;
218 
219 	ehdr = (struct elf32_hdr *)fw->data;
220 	phdrs = (struct elf32_phdr *)(ehdr + 1);
221 
222 	for (i = 0; i < ehdr->e_phnum; i++) {
223 		phdr = &phdrs[i];
224 
225 		if (!mdt_phdr_valid(phdr))
226 			continue;
227 
228 		if (phdr->p_flags & QCOM_MDT_RELOCATABLE)
229 			relocate = true;
230 
231 		if (phdr->p_paddr < min_addr)
232 			min_addr = phdr->p_paddr;
233 
234 		if (phdr->p_paddr + phdr->p_memsz > max_addr)
235 			max_addr = ALIGN(phdr->p_paddr + phdr->p_memsz, SZ_4K);
236 	}
237 
238 	metadata = qcom_mdt_read_metadata(fw, &metadata_len, fw_name, dev);
239 	if (IS_ERR(metadata)) {
240 		ret = PTR_ERR(metadata);
241 		dev_err(dev, "error %d reading firmware %s metadata\n", ret, fw_name);
242 		goto out;
243 	}
244 
245 	ret = qcom_scm_pas_init_image(pas_id, metadata, metadata_len, ctx);
246 	kfree(metadata);
247 	if (ret) {
248 		/* Invalid firmware metadata */
249 		dev_err(dev, "error %d initializing firmware %s\n", ret, fw_name);
250 		goto out;
251 	}
252 
253 	if (relocate) {
254 		ret = qcom_scm_pas_mem_setup(pas_id, mem_phys, max_addr - min_addr);
255 		if (ret) {
256 			/* Unable to set up relocation */
257 			dev_err(dev, "error %d setting up firmware %s\n", ret, fw_name);
258 			goto out;
259 		}
260 	}
261 
262 out:
263 	return ret;
264 }
265 EXPORT_SYMBOL_GPL(qcom_mdt_pas_init);
266 
267 static bool qcom_mdt_bins_are_split(const struct firmware *fw, const char *fw_name)
268 {
269 	const struct elf32_phdr *phdrs;
270 	const struct elf32_hdr *ehdr;
271 	uint64_t seg_start, seg_end;
272 	int i;
273 
274 	ehdr = (struct elf32_hdr *)fw->data;
275 	phdrs = (struct elf32_phdr *)(ehdr + 1);
276 
277 	for (i = 0; i < ehdr->e_phnum; i++) {
278 		/*
279 		 * The size of the MDT file is not padded to include any
280 		 * zero-sized segments at the end. Ignore these, as they should
281 		 * not affect the decision about image being split or not.
282 		 */
283 		if (!phdrs[i].p_filesz)
284 			continue;
285 
286 		seg_start = phdrs[i].p_offset;
287 		seg_end = phdrs[i].p_offset + phdrs[i].p_filesz;
288 		if (seg_start > fw->size || seg_end > fw->size)
289 			return true;
290 	}
291 
292 	return false;
293 }
294 
295 static int __qcom_mdt_load(struct device *dev, const struct firmware *fw,
296 			   const char *fw_name, int pas_id, void *mem_region,
297 			   phys_addr_t mem_phys, size_t mem_size,
298 			   phys_addr_t *reloc_base, bool pas_init)
299 {
300 	const struct elf32_phdr *phdrs;
301 	const struct elf32_phdr *phdr;
302 	const struct elf32_hdr *ehdr;
303 	phys_addr_t mem_reloc;
304 	phys_addr_t min_addr = PHYS_ADDR_MAX;
305 	ssize_t offset;
306 	bool relocate = false;
307 	bool is_split;
308 	void *ptr;
309 	int ret = 0;
310 	int i;
311 
312 	if (!fw || !mem_region || !mem_phys || !mem_size)
313 		return -EINVAL;
314 
315 	is_split = qcom_mdt_bins_are_split(fw, fw_name);
316 	ehdr = (struct elf32_hdr *)fw->data;
317 	phdrs = (struct elf32_phdr *)(ehdr + 1);
318 
319 	for (i = 0; i < ehdr->e_phnum; i++) {
320 		phdr = &phdrs[i];
321 
322 		if (!mdt_phdr_valid(phdr))
323 			continue;
324 
325 		if (phdr->p_flags & QCOM_MDT_RELOCATABLE)
326 			relocate = true;
327 
328 		if (phdr->p_paddr < min_addr)
329 			min_addr = phdr->p_paddr;
330 	}
331 
332 	if (relocate) {
333 		/*
334 		 * The image is relocatable, so offset each segment based on
335 		 * the lowest segment address.
336 		 */
337 		mem_reloc = min_addr;
338 	} else {
339 		/*
340 		 * Image is not relocatable, so offset each segment based on
341 		 * the allocated physical chunk of memory.
342 		 */
343 		mem_reloc = mem_phys;
344 	}
345 
346 	for (i = 0; i < ehdr->e_phnum; i++) {
347 		phdr = &phdrs[i];
348 
349 		if (!mdt_phdr_valid(phdr))
350 			continue;
351 
352 		offset = phdr->p_paddr - mem_reloc;
353 		if (offset < 0 || offset + phdr->p_memsz > mem_size) {
354 			dev_err(dev, "segment outside memory range\n");
355 			ret = -EINVAL;
356 			break;
357 		}
358 
359 		if (phdr->p_filesz > phdr->p_memsz) {
360 			dev_err(dev,
361 				"refusing to load segment %d with p_filesz > p_memsz\n",
362 				i);
363 			ret = -EINVAL;
364 			break;
365 		}
366 
367 		ptr = mem_region + offset;
368 
369 		if (phdr->p_filesz && !is_split) {
370 			/* Firmware is large enough to be non-split */
371 			if (phdr->p_offset + phdr->p_filesz > fw->size) {
372 				dev_err(dev, "file %s segment %d would be truncated\n",
373 					fw_name, i);
374 				ret = -EINVAL;
375 				break;
376 			}
377 
378 			memcpy(ptr, fw->data + phdr->p_offset, phdr->p_filesz);
379 		} else if (phdr->p_filesz) {
380 			/* Firmware not large enough, load split-out segments */
381 			ret = mdt_load_split_segment(ptr, phdrs, i, fw_name, dev);
382 			if (ret)
383 				break;
384 		}
385 
386 		if (phdr->p_memsz > phdr->p_filesz)
387 			memset(ptr + phdr->p_filesz, 0, phdr->p_memsz - phdr->p_filesz);
388 	}
389 
390 	if (reloc_base)
391 		*reloc_base = mem_reloc;
392 
393 	return ret;
394 }
395 
396 /**
397  * qcom_mdt_load() - load the firmware which header is loaded as fw
398  * @dev:	device handle to associate resources with
399  * @fw:		firmware object for the mdt file
400  * @firmware:	name of the firmware, for construction of segment file names
401  * @pas_id:	PAS identifier
402  * @mem_region:	allocated memory region to load firmware into
403  * @mem_phys:	physical address of allocated memory region
404  * @mem_size:	size of the allocated memory region
405  * @reloc_base:	adjusted physical address after relocation
406  *
407  * Returns 0 on success, negative errno otherwise.
408  */
409 int qcom_mdt_load(struct device *dev, const struct firmware *fw,
410 		  const char *firmware, int pas_id, void *mem_region,
411 		  phys_addr_t mem_phys, size_t mem_size,
412 		  phys_addr_t *reloc_base)
413 {
414 	int ret;
415 
416 	ret = qcom_mdt_pas_init(dev, fw, firmware, pas_id, mem_phys, NULL);
417 	if (ret)
418 		return ret;
419 
420 	return __qcom_mdt_load(dev, fw, firmware, pas_id, mem_region, mem_phys,
421 			       mem_size, reloc_base, true);
422 }
423 EXPORT_SYMBOL_GPL(qcom_mdt_load);
424 
425 /**
426  * qcom_mdt_load_no_init() - load the firmware which header is loaded as fw
427  * @dev:	device handle to associate resources with
428  * @fw:		firmware object for the mdt file
429  * @firmware:	name of the firmware, for construction of segment file names
430  * @pas_id:	PAS identifier
431  * @mem_region:	allocated memory region to load firmware into
432  * @mem_phys:	physical address of allocated memory region
433  * @mem_size:	size of the allocated memory region
434  * @reloc_base:	adjusted physical address after relocation
435  *
436  * Returns 0 on success, negative errno otherwise.
437  */
438 int qcom_mdt_load_no_init(struct device *dev, const struct firmware *fw,
439 			  const char *firmware, int pas_id,
440 			  void *mem_region, phys_addr_t mem_phys,
441 			  size_t mem_size, phys_addr_t *reloc_base)
442 {
443 	return __qcom_mdt_load(dev, fw, firmware, pas_id, mem_region, mem_phys,
444 			       mem_size, reloc_base, false);
445 }
446 EXPORT_SYMBOL_GPL(qcom_mdt_load_no_init);
447 
448 MODULE_DESCRIPTION("Firmware parser for Qualcomm MDT format");
449 MODULE_LICENSE("GPL v2");
450