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    Subject[PATCH v3 18/19] firmware: Add request_partial_firmware_into_buf()
    Date
    From: Scott Branden <scott.branden@broadcom.com>

    Add request_partial_firmware_into_buf() to allow for portions of a
    firmware file to be read into a buffer. This is needed when large firmware
    must be loaded in portions from a file on memory constrained systems.

    Signed-off-by: Scott Branden <scott.branden@broadcom.com>
    Co-developed-by: Kees Cook <keescook@chromium.org>
    Signed-off-by: Kees Cook <keescook@chromium.org>
    ---
    drivers/base/firmware_loader/firmware.h | 4 +
    drivers/base/firmware_loader/main.c | 109 +++++++++++++++++++-----
    include/linux/firmware.h | 12 +++
    3 files changed, 105 insertions(+), 20 deletions(-)

    diff --git a/drivers/base/firmware_loader/firmware.h b/drivers/base/firmware_loader/firmware.h
    index 7ad5fe52bc72..3f6eda46b3a2 100644
    --- a/drivers/base/firmware_loader/firmware.h
    +++ b/drivers/base/firmware_loader/firmware.h
    @@ -32,6 +32,8 @@
    * @FW_OPT_FALLBACK_PLATFORM: Enable fallback to device fw copy embedded in
    * the platform's main firmware. If both this fallback and the sysfs
    * fallback are enabled, then this fallback will be tried first.
    + * @FW_OPT_PARTIAL: Allow partial read of firmware instead of needing to read
    + * entire file.
    */
    enum fw_opt {
    FW_OPT_UEVENT = BIT(0),
    @@ -41,6 +43,7 @@ enum fw_opt {
    FW_OPT_NOCACHE = BIT(4),
    FW_OPT_NOFALLBACK_SYSFS = BIT(5),
    FW_OPT_FALLBACK_PLATFORM = BIT(6),
    + FW_OPT_PARTIAL = BIT(7),
    };

    enum fw_status {
    @@ -68,6 +71,7 @@ struct fw_priv {
    void *data;
    size_t size;
    size_t allocated_size;
    + size_t offset;
    u32 opt_flags;
    #ifdef CONFIG_FW_LOADER_PAGED_BUF
    bool is_paged_buf;
    diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
    index 814a18cc51bd..7aa22bdc2f60 100644
    --- a/drivers/base/firmware_loader/main.c
    +++ b/drivers/base/firmware_loader/main.c
    @@ -170,10 +170,19 @@ static struct fw_priv *__allocate_fw_priv(const char *fw_name,
    struct firmware_cache *fwc,
    void *dbuf,
    size_t size,
    + size_t offset,
    u32 opt_flags)
    {
    struct fw_priv *fw_priv;

    + /* For a partial read, the buffer must be preallocated. */
    + if ((opt_flags & FW_OPT_PARTIAL) && !dbuf)
    + return NULL;
    +
    + /* Only partial reads are allowed to use an offset. */
    + if (offset != 0 && !(opt_flags & FW_OPT_PARTIAL))
    + return NULL;
    +
    fw_priv = kzalloc(sizeof(*fw_priv), GFP_ATOMIC);
    if (!fw_priv)
    return NULL;
    @@ -188,6 +197,7 @@ static struct fw_priv *__allocate_fw_priv(const char *fw_name,
    fw_priv->fwc = fwc;
    fw_priv->data = dbuf;
    fw_priv->allocated_size = size;
    + fw_priv->offset = offset;
    fw_priv->opt_flags = opt_flags;
    fw_state_init(fw_priv);
    #ifdef CONFIG_FW_LOADER_USER_HELPER
    @@ -216,12 +226,17 @@ static int alloc_lookup_fw_priv(const char *fw_name,
    struct fw_priv **fw_priv,
    void *dbuf,
    size_t size,
    + size_t offset,
    u32 opt_flags)
    {
    struct fw_priv *tmp;

    spin_lock(&fwc->lock);
    - if (!(opt_flags & FW_OPT_NOCACHE)) {
    + /*
    + * Do not merge requests that are marked to be non-cached or
    + * are performing partial reads.
    + */
    + if (!(opt_flags & (FW_OPT_NOCACHE | FW_OPT_PARTIAL))) {
    tmp = __lookup_fw_priv(fw_name);
    if (tmp) {
    kref_get(&tmp->ref);
    @@ -232,7 +247,7 @@ static int alloc_lookup_fw_priv(const char *fw_name,
    }
    }

    - tmp = __allocate_fw_priv(fw_name, fwc, dbuf, size, opt_flags);
    + tmp = __allocate_fw_priv(fw_name, fwc, dbuf, size, offset, opt_flags);
    if (tmp) {
    INIT_LIST_HEAD(&tmp->list);
    if (!(opt_flags & FW_OPT_NOCACHE))
    @@ -439,6 +454,12 @@ static int fw_decompress_xz(struct device *dev, struct fw_priv *fw_priv,
    else
    return fw_decompress_xz_pages(dev, fw_priv, in_size, in_buffer);
    }
    +#else
    +static inline int fw_decompress_xz(struct device *dev, struct fw_priv *fw_priv,
    + size_t in_size, const void *in_buffer)
    +{
    + return -ENOENT;
    +}
    #endif /* CONFIG_FW_LOADER_COMPRESS */

    /* direct firmware loading support */
    @@ -485,6 +506,9 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
    return -ENOMEM;

    for (i = 0; i < ARRAY_SIZE(fw_path); i++) {
    + size_t file_size = 0;
    + size_t *file_size_ptr = NULL;
    +
    /* skip the unset customized path */
    if (!fw_path[i][0])
    continue;
    @@ -498,9 +522,18 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,

    fw_priv->size = 0;

    + /*
    + * The total file size is only examined when doing a partial
    + * read; the "full read" case needs to fail if the whole
    + * firmware was not completely loaded.
    + */
    + if ((fw_priv->opt_flags & FW_OPT_PARTIAL) && buffer)
    + file_size_ptr = &file_size;
    +
    /* load firmware files from the mount namespace of init */
    - rc = kernel_read_file_from_path_initns(path, 0, &buffer, msize,
    - NULL,
    + rc = kernel_read_file_from_path_initns(path, fw_priv->offset,
    + &buffer, msize,
    + file_size_ptr,
    READING_FIRMWARE);
    if (rc < 0) {
    if (rc != -ENOENT)
    @@ -691,7 +724,7 @@ int assign_fw(struct firmware *fw, struct device *device)
    static int
    _request_firmware_prepare(struct firmware **firmware_p, const char *name,
    struct device *device, void *dbuf, size_t size,
    - u32 opt_flags)
    + size_t offset, u32 opt_flags)
    {
    struct firmware *firmware;
    struct fw_priv *fw_priv;
    @@ -710,7 +743,7 @@ _request_firmware_prepare(struct firmware **firmware_p, const char *name,
    }

    ret = alloc_lookup_fw_priv(name, &fw_cache, &fw_priv, dbuf, size,
    - opt_flags);
    + offset, opt_flags);

    /*
    * bind with 'priv' now to avoid warning in failure path
    @@ -757,9 +790,10 @@ static void fw_abort_batch_reqs(struct firmware *fw)
    static int
    _request_firmware(const struct firmware **firmware_p, const char *name,
    struct device *device, void *buf, size_t size,
    - u32 opt_flags)
    + size_t offset, u32 opt_flags)
    {
    struct firmware *fw = NULL;
    + bool nondirect = false;
    int ret;

    if (!firmware_p)
    @@ -771,18 +805,20 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
    }

    ret = _request_firmware_prepare(&fw, name, device, buf, size,
    - opt_flags);
    + offset, opt_flags);
    if (ret <= 0) /* error or already assigned */
    goto out;

    ret = fw_get_filesystem_firmware(device, fw->priv, "", NULL);
    -#ifdef CONFIG_FW_LOADER_COMPRESS
    - if (ret == -ENOENT)
    +
    + /* Only full reads can support decompression, platform, and sysfs. */
    + if (!(opt_flags & FW_OPT_PARTIAL))
    + nondirect = true;
    +
    + if (ret == -ENOENT && nondirect)
    ret = fw_get_filesystem_firmware(device, fw->priv, ".xz",
    fw_decompress_xz);
    -#endif
    -
    - if (ret == -ENOENT)
    + if (ret == -ENOENT && nondirect)
    ret = firmware_fallback_platform(fw->priv);

    if (ret) {
    @@ -790,7 +826,9 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
    dev_warn(device,
    "Direct firmware load for %s failed with error %d\n",
    name, ret);
    - ret = firmware_fallback_sysfs(fw, name, device, opt_flags, ret);
    + if (nondirect)
    + ret = firmware_fallback_sysfs(fw, name, device,
    + opt_flags, ret);
    } else
    ret = assign_fw(fw, device);

    @@ -833,7 +871,7 @@ request_firmware(const struct firmware **firmware_p, const char *name,

    /* Need to pin this module until return */
    __module_get(THIS_MODULE);
    - ret = _request_firmware(firmware_p, name, device, NULL, 0,
    + ret = _request_firmware(firmware_p, name, device, NULL, 0, 0,
    FW_OPT_UEVENT);
    module_put(THIS_MODULE);
    return ret;
    @@ -860,7 +898,7 @@ int firmware_request_nowarn(const struct firmware **firmware, const char *name,

    /* Need to pin this module until return */
    __module_get(THIS_MODULE);
    - ret = _request_firmware(firmware, name, device, NULL, 0,
    + ret = _request_firmware(firmware, name, device, NULL, 0, 0,
    FW_OPT_UEVENT | FW_OPT_NO_WARN);
    module_put(THIS_MODULE);
    return ret;
    @@ -884,7 +922,7 @@ int request_firmware_direct(const struct firmware **firmware_p,
    int ret;

    __module_get(THIS_MODULE);
    - ret = _request_firmware(firmware_p, name, device, NULL, 0,
    + ret = _request_firmware(firmware_p, name, device, NULL, 0, 0,
    FW_OPT_UEVENT | FW_OPT_NO_WARN |
    FW_OPT_NOFALLBACK_SYSFS);
    module_put(THIS_MODULE);
    @@ -909,7 +947,7 @@ int firmware_request_platform(const struct firmware **firmware,

    /* Need to pin this module until return */
    __module_get(THIS_MODULE);
    - ret = _request_firmware(firmware, name, device, NULL, 0,
    + ret = _request_firmware(firmware, name, device, NULL, 0, 0,
    FW_OPT_UEVENT | FW_OPT_FALLBACK_PLATFORM);
    module_put(THIS_MODULE);
    return ret;
    @@ -965,13 +1003,44 @@ request_firmware_into_buf(const struct firmware **firmware_p, const char *name,
    return -EOPNOTSUPP;

    __module_get(THIS_MODULE);
    - ret = _request_firmware(firmware_p, name, device, buf, size,
    + ret = _request_firmware(firmware_p, name, device, buf, size, 0,
    FW_OPT_UEVENT | FW_OPT_NOCACHE);
    module_put(THIS_MODULE);
    return ret;
    }
    EXPORT_SYMBOL(request_firmware_into_buf);

    +/**
    + * request_partial_firmware_into_buf() - load partial firmware into a previously allocated buffer
    + * @firmware_p: pointer to firmware image
    + * @name: name of firmware file
    + * @device: device for which firmware is being loaded and DMA region allocated
    + * @buf: address of buffer to load firmware into
    + * @size: size of buffer
    + * @offset: offset into file to read
    + *
    + * This function works pretty much like request_firmware_into_buf except
    + * it allows a partial read of the file.
    + */
    +int
    +request_partial_firmware_into_buf(const struct firmware **firmware_p,
    + const char *name, struct device *device,
    + void *buf, size_t size, size_t offset)
    +{
    + int ret;
    +
    + if (fw_cache_is_setup(device, name))
    + return -EOPNOTSUPP;
    +
    + __module_get(THIS_MODULE);
    + ret = _request_firmware(firmware_p, name, device, buf, size, offset,
    + FW_OPT_UEVENT | FW_OPT_NOCACHE |
    + FW_OPT_PARTIAL);
    + module_put(THIS_MODULE);
    + return ret;
    +}
    +EXPORT_SYMBOL(request_partial_firmware_into_buf);
    +
    /**
    * release_firmware() - release the resource associated with a firmware image
    * @fw: firmware resource to release
    @@ -1004,7 +1073,7 @@ static void request_firmware_work_func(struct work_struct *work)

    fw_work = container_of(work, struct firmware_work, work);

    - _request_firmware(&fw, fw_work->name, fw_work->device, NULL, 0,
    + _request_firmware(&fw, fw_work->name, fw_work->device, NULL, 0, 0,
    fw_work->opt_flags);
    fw_work->cont(fw, fw_work->context);
    put_device(fw_work->device); /* taken in request_firmware_nowait() */
    diff --git a/include/linux/firmware.h b/include/linux/firmware.h
    index cb3e2c06ed8a..c15acadc6cf4 100644
    --- a/include/linux/firmware.h
    +++ b/include/linux/firmware.h
    @@ -53,6 +53,9 @@ int request_firmware_direct(const struct firmware **fw, const char *name,
    struct device *device);
    int request_firmware_into_buf(const struct firmware **firmware_p,
    const char *name, struct device *device, void *buf, size_t size);
    +int request_partial_firmware_into_buf(const struct firmware **firmware_p,
    + const char *name, struct device *device,
    + void *buf, size_t size, size_t offset);

    void release_firmware(const struct firmware *fw);
    #else
    @@ -102,6 +105,15 @@ static inline int request_firmware_into_buf(const struct firmware **firmware_p,
    return -EINVAL;
    }

    +static inline int request_partial_firmware_into_buf
    + (const struct firmware **firmware_p,
    + const char *name,
    + struct device *device,
    + void *buf, size_t size, size_t offset)
    +{
    + return -EINVAL;
    +}
    +
    #endif

    int firmware_request_cache(struct device *device, const char *name);
    --
    2.25.1
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      Last update: 2020-07-24 23:45    [W:4.301 / U:0.368 seconds]
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