remoteproc_elf_loader.c

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/*
 * Remote Processor Framework Elf loader
 *
 * Copyright (C) 2011 Texas Instruments, Inc.
 * Copyright (C) 2011 Google, Inc.
 *
 * Ohad Ben-Cohen <[email protected]>
 * Brian Swetland <[email protected]>
 * Mark Grosen <[email protected]>
 * Fernando Guzman Lugo <[email protected]>
 * Suman Anna <[email protected]>
 * Robert Tivy <[email protected]>
 * Armando Uribe De Leon <[email protected]>
 * Sjur Brændeland <[email protected]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#define pr_fmt(fmt)    "%s: " fmt, __func__

#include <linux/module.h>
#include <linux/firmware.h>
#include <linux/remoteproc.h>
#include <linux/elf.h>

#include "remoteproc_internal.h"

static int
rproc_elf_sanity_check(struct rproc *rproc, const struct firmware *fw)
{
    const char *name = rproc->firmware;
    struct device *dev = &rproc->dev;
    struct elf32_hdr *ehdr;
    char class;

    if (!fw) {
        dev_err(dev, "failed to load %s\n", name);
        return -EINVAL;
    }

    if (fw->size < sizeof(struct elf32_hdr)) {
        dev_err(dev, "Image is too small\n");
        return -EINVAL;
    }

    ehdr = (struct elf32_hdr *)fw->data;

    /* We only support ELF32 at this point */
    class = ehdr->e_ident[EI_CLASS];
    if (class != ELFCLASS32) {
        dev_err(dev, "Unsupported class: %d\n", class);
        return -EINVAL;
    }

    /* We assume the firmware has the same endianess as the host */
# ifdef __LITTLE_ENDIAN
    if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB) {
# else /* BIG ENDIAN */
    if (ehdr->e_ident[EI_DATA] != ELFDATA2MSB) {
# endif
        dev_err(dev, "Unsupported firmware endianess\n");
        return -EINVAL;
    }

    if (fw->size < ehdr->e_shoff + sizeof(struct elf32_shdr)) {
        dev_err(dev, "Image is too small\n");
        return -EINVAL;
    }

    if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG)) {
        dev_err(dev, "Image is corrupted (bad magic)\n");
        return -EINVAL;
    }

    if (ehdr->e_phnum == 0) {
        dev_err(dev, "No loadable segments\n");
        return -EINVAL;
    }

    if (ehdr->e_phoff > fw->size) {
        dev_err(dev, "Firmware size is too small\n");
        return -EINVAL;
    }

    return 0;
}

static
u32 rproc_elf_get_boot_addr(struct rproc *rproc, const struct firmware *fw)
{
    struct elf32_hdr *ehdr  = (struct elf32_hdr *)fw->data;

    return ehdr->e_entry;
}

static int
rproc_elf_load_segments(struct rproc *rproc, const struct firmware *fw)
{
    struct device *dev = &rproc->dev;
    struct elf32_hdr *ehdr;
    struct elf32_phdr *phdr;
    int i, ret = 0;
    const u8 *elf_data = fw->data;

    ehdr = (struct elf32_hdr *)elf_data;
    phdr = (struct elf32_phdr *)(elf_data + ehdr->e_phoff);

    /* go through the available ELF segments */
    for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
        u32 da = phdr->p_paddr;
        u32 memsz = phdr->p_memsz;
        u32 filesz = phdr->p_filesz;
        u32 offset = phdr->p_offset;
        void *ptr;

        if (phdr->p_type != PT_LOAD)
            continue;

        dev_dbg(dev, "phdr: type %d da 0x%x memsz 0x%x filesz 0x%x\n",
                    phdr->p_type, da, memsz, filesz);

        if (filesz > memsz) {
            dev_err(dev, "bad phdr filesz 0x%x memsz 0x%x\n",
                            filesz, memsz);
            ret = -EINVAL;
            break;
        }

        if (offset + filesz > fw->size) {
            dev_err(dev, "truncated fw: need 0x%x avail 0x%zx\n",
                    offset + filesz, fw->size);
            ret = -EINVAL;
            break;
        }

        /* grab the kernel address for this device address */
        ptr = rproc_da_to_va(rproc, da, memsz);
        if (!ptr) {
            dev_err(dev, "bad phdr da 0x%x mem 0x%x\n", da, memsz);
            ret = -EINVAL;
            break;
        }

        /* put the segment where the remote processor expects it */
        if (phdr->p_filesz)
            memcpy(ptr, elf_data + phdr->p_offset, filesz);

        /*
         * Zero out remaining memory for this segment.
         *
         * This isn't strictly required since dma_alloc_coherent already
         * did this for us. albeit harmless, we may consider removing
         * this.
         */
        if (memsz > filesz)
            memset(ptr + filesz, 0, memsz - filesz);
    }

    return ret;
}

static struct resource_table *
rproc_elf_find_rsc_table(struct rproc *rproc, const struct firmware *fw,
                            int *tablesz)
{
    struct elf32_hdr *ehdr;
    struct elf32_shdr *shdr;
    const char *name_table;
    struct device *dev = &rproc->dev;
    struct resource_table *table = NULL;
    int i;
    const u8 *elf_data = fw->data;

    ehdr = (struct elf32_hdr *)elf_data;
    shdr = (struct elf32_shdr *)(elf_data + ehdr->e_shoff);
    name_table = elf_data + shdr[ehdr->e_shstrndx].sh_offset;

    /* look for the resource table and handle it */
    for (i = 0; i < ehdr->e_shnum; i++, shdr++) {
        int size = shdr->sh_size;
        int offset = shdr->sh_offset;

        if (strcmp(name_table + shdr->sh_name, ".resource_table"))
            continue;

        table = (struct resource_table *)(elf_data + offset);

        /* make sure we have the entire table */
        if (offset + size > fw->size) {
            dev_err(dev, "resource table truncated\n");
            return NULL;
        }

        /* make sure table has at least the header */
        if (sizeof(struct resource_table) > size) {
            dev_err(dev, "header-less resource table\n");
            return NULL;
        }

        /* we don't support any version beyond the first */
        if (table->ver != 1) {
            dev_err(dev, "unsupported fw ver: %d\n", table->ver);
            return NULL;
        }

        /* make sure reserved bytes are zeroes */
        if (table->reserved[0] || table->reserved[1]) {
            dev_err(dev, "non zero reserved bytes\n");
            return NULL;
        }

        /* make sure the offsets array isn't truncated */
        if (table->num * sizeof(table->offset[0]) +
                sizeof(struct resource_table) > size) {
            dev_err(dev, "resource table incomplete\n");
            return NULL;
        }

        *tablesz = shdr->sh_size;
        break;
    }

    return table;
}

const struct rproc_fw_ops rproc_elf_fw_ops = {
    .load = rproc_elf_load_segments,
    .find_rsc_table = rproc_elf_find_rsc_table,
    .sanity_check = rproc_elf_sanity_check,
    .get_boot_addr = rproc_elf_get_boot_addr
};