1/*
2 * Remote Processor Framework Elf loader
3 *
4 * Copyright (C) 2011 Texas Instruments, Inc.
5 * Copyright (C) 2011 Google, Inc.
6 *
7 * Ohad Ben-Cohen <ohad@wizery.com>
8 * Brian Swetland <swetland@google.com>
9 * Mark Grosen <mgrosen@ti.com>
10 * Fernando Guzman Lugo <fernando.lugo@ti.com>
11 * Suman Anna <s-anna@ti.com>
12 * Robert Tivy <rtivy@ti.com>
13 * Armando Uribe De Leon <x0095078@ti.com>
14 * Sjur Brændeland <sjur.brandeland@stericsson.com>
15 *
16 * This program is free software; you can redistribute it and/or
17 * modify it under the terms of the GNU General Public License
18 * version 2 as published by the Free Software Foundation.
19 *
20 * This program is distributed in the hope that it will be useful,
21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
23 * GNU General Public License for more details.
24 */
25
26#define pr_fmt(fmt)    "%s: " fmt, __func__
27
28#include <linux/module.h>
29#include <linux/firmware.h>
30#include <linux/remoteproc.h>
31#include <linux/elf.h>
32
33#include "remoteproc_internal.h"
34
35/**
36 * rproc_elf_sanity_check() - Sanity Check ELF firmware image
37 * @rproc: the remote processor handle
38 * @fw: the ELF firmware image
39 *
40 * Make sure this fw image is sane.
41 */
42static int
43rproc_elf_sanity_check(struct rproc *rproc, const struct firmware *fw)
44{
45	const char *name = rproc->firmware;
46	struct device *dev = &rproc->dev;
47	struct elf32_hdr *ehdr;
48	char class;
49
50	if (!fw) {
51		dev_err(dev, "failed to load %s\n", name);
52		return -EINVAL;
53	}
54
55	if (fw->size < sizeof(struct elf32_hdr)) {
56		dev_err(dev, "Image is too small\n");
57		return -EINVAL;
58	}
59
60	ehdr = (struct elf32_hdr *)fw->data;
61
62	/* We only support ELF32 at this point */
63	class = ehdr->e_ident[EI_CLASS];
64	if (class != ELFCLASS32) {
65		dev_err(dev, "Unsupported class: %d\n", class);
66		return -EINVAL;
67	}
68
69	/* We assume the firmware has the same endianness as the host */
70# ifdef __LITTLE_ENDIAN
71	if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB) {
72# else /* BIG ENDIAN */
73	if (ehdr->e_ident[EI_DATA] != ELFDATA2MSB) {
74# endif
75		dev_err(dev, "Unsupported firmware endianness\n");
76		return -EINVAL;
77	}
78
79	if (fw->size < ehdr->e_shoff + sizeof(struct elf32_shdr)) {
80		dev_err(dev, "Image is too small\n");
81		return -EINVAL;
82	}
83
84	if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG)) {
85		dev_err(dev, "Image is corrupted (bad magic)\n");
86		return -EINVAL;
87	}
88
89	if (ehdr->e_phnum == 0) {
90		dev_err(dev, "No loadable segments\n");
91		return -EINVAL;
92	}
93
94	if (ehdr->e_phoff > fw->size) {
95		dev_err(dev, "Firmware size is too small\n");
96		return -EINVAL;
97	}
98
99	return 0;
100}
101
102/**
103 * rproc_elf_get_boot_addr() - Get rproc's boot address.
104 * @rproc: the remote processor handle
105 * @fw: the ELF firmware image
106 *
107 * This function returns the entry point address of the ELF
108 * image.
109 *
110 * Note that the boot address is not a configurable property of all remote
111 * processors. Some will always boot at a specific hard-coded address.
112 */
113static
114u32 rproc_elf_get_boot_addr(struct rproc *rproc, const struct firmware *fw)
115{
116	struct elf32_hdr *ehdr  = (struct elf32_hdr *)fw->data;
117
118	return ehdr->e_entry;
119}
120
121/**
122 * rproc_elf_load_segments() - load firmware segments to memory
123 * @rproc: remote processor which will be booted using these fw segments
124 * @fw: the ELF firmware image
125 *
126 * This function loads the firmware segments to memory, where the remote
127 * processor expects them.
128 *
129 * Some remote processors will expect their code and data to be placed
130 * in specific device addresses, and can't have them dynamically assigned.
131 *
132 * We currently support only those kind of remote processors, and expect
133 * the program header's paddr member to contain those addresses. We then go
134 * through the physically contiguous "carveout" memory regions which we
135 * allocated (and mapped) earlier on behalf of the remote processor,
136 * and "translate" device address to kernel addresses, so we can copy the
137 * segments where they are expected.
138 *
139 * Currently we only support remote processors that required carveout
140 * allocations and got them mapped onto their iommus. Some processors
141 * might be different: they might not have iommus, and would prefer to
142 * directly allocate memory for every segment/resource. This is not yet
143 * supported, though.
144 */
145static int
146rproc_elf_load_segments(struct rproc *rproc, const struct firmware *fw)
147{
148	struct device *dev = &rproc->dev;
149	struct elf32_hdr *ehdr;
150	struct elf32_phdr *phdr;
151	int i, ret = 0;
152	const u8 *elf_data = fw->data;
153
154	ehdr = (struct elf32_hdr *)elf_data;
155	phdr = (struct elf32_phdr *)(elf_data + ehdr->e_phoff);
156
157	/* go through the available ELF segments */
158	for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
159		u32 da = phdr->p_paddr;
160		u32 memsz = phdr->p_memsz;
161		u32 filesz = phdr->p_filesz;
162		u32 offset = phdr->p_offset;
163		void *ptr;
164
165		if (phdr->p_type != PT_LOAD)
166			continue;
167
168		dev_dbg(dev, "phdr: type %d da 0x%x memsz 0x%x filesz 0x%x\n",
169					phdr->p_type, da, memsz, filesz);
170
171		if (filesz > memsz) {
172			dev_err(dev, "bad phdr filesz 0x%x memsz 0x%x\n",
173							filesz, memsz);
174			ret = -EINVAL;
175			break;
176		}
177
178		if (offset + filesz > fw->size) {
179			dev_err(dev, "truncated fw: need 0x%x avail 0x%zx\n",
180					offset + filesz, fw->size);
181			ret = -EINVAL;
182			break;
183		}
184
185		/* grab the kernel address for this device address */
186		ptr = rproc_da_to_va(rproc, da, memsz);
187		if (!ptr) {
188			dev_err(dev, "bad phdr da 0x%x mem 0x%x\n", da, memsz);
189			ret = -EINVAL;
190			break;
191		}
192
193		/* put the segment where the remote processor expects it */
194		if (phdr->p_filesz)
195			memcpy(ptr, elf_data + phdr->p_offset, filesz);
196
197		/*
198		 * Zero out remaining memory for this segment.
199		 *
200		 * This isn't strictly required since dma_alloc_coherent already
201		 * did this for us. albeit harmless, we may consider removing
202		 * this.
203		 */
204		if (memsz > filesz)
205			memset(ptr + filesz, 0, memsz - filesz);
206	}
207
208	return ret;
209}
210
211static struct elf32_shdr *
212find_table(struct device *dev, struct elf32_hdr *ehdr, size_t fw_size)
213{
214	struct elf32_shdr *shdr;
215	int i;
216	const char *name_table;
217	struct resource_table *table = NULL;
218	const u8 *elf_data = (void *)ehdr;
219
220	/* look for the resource table and handle it */
221	shdr = (struct elf32_shdr *)(elf_data + ehdr->e_shoff);
222	name_table = elf_data + shdr[ehdr->e_shstrndx].sh_offset;
223
224	for (i = 0; i < ehdr->e_shnum; i++, shdr++) {
225		u32 size = shdr->sh_size;
226		u32 offset = shdr->sh_offset;
227
228		if (strcmp(name_table + shdr->sh_name, ".resource_table"))
229			continue;
230
231		table = (struct resource_table *)(elf_data + offset);
232
233		/* make sure we have the entire table */
234		if (offset + size > fw_size || offset + size < size) {
235			dev_err(dev, "resource table truncated\n");
236			return NULL;
237		}
238
239		/* make sure table has at least the header */
240		if (sizeof(struct resource_table) > size) {
241			dev_err(dev, "header-less resource table\n");
242			return NULL;
243		}
244
245		/* we don't support any version beyond the first */
246		if (table->ver != 1) {
247			dev_err(dev, "unsupported fw ver: %d\n", table->ver);
248			return NULL;
249		}
250
251		/* make sure reserved bytes are zeroes */
252		if (table->reserved[0] || table->reserved[1]) {
253			dev_err(dev, "non zero reserved bytes\n");
254			return NULL;
255		}
256
257		/* make sure the offsets array isn't truncated */
258		if (table->num * sizeof(table->offset[0]) +
259				sizeof(struct resource_table) > size) {
260			dev_err(dev, "resource table incomplete\n");
261			return NULL;
262		}
263
264		return shdr;
265	}
266
267	return NULL;
268}
269
270/**
271 * rproc_elf_find_rsc_table() - find the resource table
272 * @rproc: the rproc handle
273 * @fw: the ELF firmware image
274 * @tablesz: place holder for providing back the table size
275 *
276 * This function finds the resource table inside the remote processor's
277 * firmware. It is used both upon the registration of @rproc (in order
278 * to look for and register the supported virito devices), and when the
279 * @rproc is booted.
280 *
281 * Returns the pointer to the resource table if it is found, and write its
282 * size into @tablesz. If a valid table isn't found, NULL is returned
283 * (and @tablesz isn't set).
284 */
285static struct resource_table *
286rproc_elf_find_rsc_table(struct rproc *rproc, const struct firmware *fw,
287			 int *tablesz)
288{
289	struct elf32_hdr *ehdr;
290	struct elf32_shdr *shdr;
291	struct device *dev = &rproc->dev;
292	struct resource_table *table = NULL;
293	const u8 *elf_data = fw->data;
294
295	ehdr = (struct elf32_hdr *)elf_data;
296
297	shdr = find_table(dev, ehdr, fw->size);
298	if (!shdr)
299		return NULL;
300
301	table = (struct resource_table *)(elf_data + shdr->sh_offset);
302	*tablesz = shdr->sh_size;
303
304	return table;
305}
306
307/**
308 * rproc_elf_find_loaded_rsc_table() - find the loaded resource table
309 * @rproc: the rproc handle
310 * @fw: the ELF firmware image
311 *
312 * This function finds the location of the loaded resource table. Don't
313 * call this function if the table wasn't loaded yet - it's a bug if you do.
314 *
315 * Returns the pointer to the resource table if it is found or NULL otherwise.
316 * If the table wasn't loaded yet the result is unspecified.
317 */
318static struct resource_table *
319rproc_elf_find_loaded_rsc_table(struct rproc *rproc, const struct firmware *fw)
320{
321	struct elf32_hdr *ehdr = (struct elf32_hdr *)fw->data;
322	struct elf32_shdr *shdr;
323
324	shdr = find_table(&rproc->dev, ehdr, fw->size);
325	if (!shdr)
326		return NULL;
327
328	return rproc_da_to_va(rproc, shdr->sh_addr, shdr->sh_size);
329}
330
331const struct rproc_fw_ops rproc_elf_fw_ops = {
332	.load = rproc_elf_load_segments,
333	.find_rsc_table = rproc_elf_find_rsc_table,
334	.find_loaded_rsc_table = rproc_elf_find_loaded_rsc_table,
335	.sanity_check = rproc_elf_sanity_check,
336	.get_boot_addr = rproc_elf_get_boot_addr
337};
338