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Subject[PATCH v2.5 2/3] firmware: Add support for loading compressed files
Date
This patch adds the support for loading compressed firmware files.
The primary motivation is to reduce the storage size; e.g. currently
the files in /lib/firmware on my machine counts up to 419MB, while
they can be reduced to 130MB by file compression.

The patch introduces a new kconfig option CONFIG_FW_LOADER_COMPRESS.
Even with this option set, the firmware loader still tries to load the
original firmware file as-is at first, but then falls back to the file
with ".xz" extension when it's not found, and the decompressed file
content is returned to the caller of request_firmware(). So, no
change is needed for the rest.

Currently only XZ format is supported. A caveat is that the kernel XZ
helper code supports only CRC32 (or none) integrity check type, so
you'll have to compress the files via xz -C crc32 option.

Since we can't determine the expanded size immediately from an XZ
file, the patch re-uses the paged buffer that was used for the
user-mode fallback; it puts the decompressed content page, which are
vmapped at the end. The paged buffer code is conditionally built with
a new Kconfig that is selected automatically.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
v1->v2.5: Slight code refactoring, no functional changes

drivers/base/firmware_loader/Kconfig | 18 ++++
drivers/base/firmware_loader/firmware.h | 8 +-
drivers/base/firmware_loader/main.c | 147 ++++++++++++++++++++++++++++++--
3 files changed, 161 insertions(+), 12 deletions(-)

diff --git a/drivers/base/firmware_loader/Kconfig b/drivers/base/firmware_loader/Kconfig
index 38f2da6f5c2b..3f9e274e2ed3 100644
--- a/drivers/base/firmware_loader/Kconfig
+++ b/drivers/base/firmware_loader/Kconfig
@@ -26,6 +26,9 @@ config FW_LOADER

if FW_LOADER

+config FW_LOADER_PAGED_BUF
+ bool
+
config EXTRA_FIRMWARE
string "Build named firmware blobs into the kernel binary"
help
@@ -67,6 +70,7 @@ config EXTRA_FIRMWARE_DIR

config FW_LOADER_USER_HELPER
bool "Enable the firmware sysfs fallback mechanism"
+ select FW_LOADER_PAGED_BUF
help
This option enables a sysfs loading facility to enable firmware
loading to the kernel through userspace as a fallback mechanism
@@ -151,5 +155,19 @@ config FW_LOADER_USER_HELPER_FALLBACK

If you are unsure about this, say N here.

+config FW_LOADER_COMPRESS
+ bool "Enable compressed firmware support"
+ select FW_LOADER_PAGED_BUF
+ select XZ_DEC
+ help
+ This option enables the support for loading compressed firmware
+ files. The caller of firmware API receives the decompressed file
+ content. The compressed file is loaded as a fallback, only after
+ loading the raw file failed at first.
+
+ Currently only XZ-compressed files are supported, and they have to
+ be compressed with either none or crc32 integrity check type (pass
+ "-C crc32" option to xz command).
+
endif # FW_LOADER
endmenu
diff --git a/drivers/base/firmware_loader/firmware.h b/drivers/base/firmware_loader/firmware.h
index 35f4e58b2d98..7048a41973ed 100644
--- a/drivers/base/firmware_loader/firmware.h
+++ b/drivers/base/firmware_loader/firmware.h
@@ -64,12 +64,14 @@ struct fw_priv {
void *data;
size_t size;
size_t allocated_size;
-#ifdef CONFIG_FW_LOADER_USER_HELPER
+#ifdef CONFIG_FW_LOADER_PAGED_BUF
bool is_paged_buf;
- bool need_uevent;
struct page **pages;
int nr_pages;
int page_array_size;
+#endif
+#ifdef CONFIG_FW_LOADER_USER_HELPER
+ bool need_uevent;
struct list_head pending_list;
#endif
const char *fw_name;
@@ -133,7 +135,7 @@ static inline void fw_state_done(struct fw_priv *fw_priv)
int assign_fw(struct firmware *fw, struct device *device,
enum fw_opt opt_flags);

-#ifdef CONFIG_FW_LOADER_USER_HELPER
+#ifdef CONFIG_FW_LOADER_PAGED_BUF
void fw_free_paged_buf(struct fw_priv *fw_priv);
int fw_grow_paged_buf(struct fw_priv *fw_priv, int pages_needed);
int fw_map_paged_buf(struct fw_priv *fw_priv);
diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index 7e12732f4705..bf44c79beae9 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -33,6 +33,7 @@
#include <linux/syscore_ops.h>
#include <linux/reboot.h>
#include <linux/security.h>
+#include <linux/xz.h>

#include <generated/utsrelease.h>

@@ -266,7 +267,7 @@ static void free_fw_priv(struct fw_priv *fw_priv)
spin_unlock(&fwc->lock);
}

-#ifdef CONFIG_FW_LOADER_USER_HELPER
+#ifdef CONFIG_FW_LOADER_PAGED_BUF
void fw_free_paged_buf(struct fw_priv *fw_priv)
{
int i;
@@ -335,6 +336,105 @@ int fw_map_paged_buf(struct fw_priv *fw_priv)
}
#endif

+/*
+ * XZ-compressed firmware support
+ */
+#ifdef CONFIG_FW_LOADER_COMPRESS
+/* show an error and return the standard error code */
+static int fw_decompress_xz_error(struct device *dev, enum xz_ret xz_ret)
+{
+ if (xz_ret != XZ_STREAM_END) {
+ dev_warn(dev, "xz decompression failed (xz_ret=%d)\n", xz_ret);
+ return xz_ret == XZ_MEM_ERROR ? -ENOMEM : -EINVAL;
+ }
+ return 0;
+}
+
+/* single-shot decompression onto the pre-allocated buffer */
+static int fw_decompress_xz_single(struct device *dev, struct fw_priv *fw_priv,
+ size_t in_size, const void *in_buffer)
+{
+ struct xz_dec *xz_dec;
+ struct xz_buf xz_buf;
+ enum xz_ret xz_ret;
+
+ xz_dec = xz_dec_init(XZ_SINGLE, (u32)-1);
+ if (!xz_dec)
+ return -ENOMEM;
+
+ xz_buf.in_size = in_size;
+ xz_buf.in = in_buffer;
+ xz_buf.in_pos = 0;
+ xz_buf.out_size = fw_priv->allocated_size;
+ xz_buf.out = fw_priv->data;
+ xz_buf.out_pos = 0;
+
+ xz_ret = xz_dec_run(xz_dec, &xz_buf);
+ xz_dec_end(xz_dec);
+
+ fw_priv->size = xz_buf.out_pos;
+ return fw_decompress_xz_error(dev, xz_ret);
+}
+
+/* decompression on paged buffer and map it */
+static int fw_decompress_xz_pages(struct device *dev, struct fw_priv *fw_priv,
+ size_t in_size, const void *in_buffer)
+{
+ struct xz_dec *xz_dec;
+ struct xz_buf xz_buf;
+ enum xz_ret xz_ret;
+ struct page *page;
+ int err = 0;
+
+ xz_dec = xz_dec_init(XZ_DYNALLOC, (u32)-1);
+ if (!xz_dec)
+ return -ENOMEM;
+
+ xz_buf.in_size = in_size;
+ xz_buf.in = in_buffer;
+ xz_buf.in_pos = 0;
+
+ fw_priv->is_paged_buf = true;
+ fw_priv->size = 0;
+ do {
+ if (fw_grow_paged_buf(fw_priv, fw_priv->nr_pages + 1)) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ /* decompress onto the new allocated page */
+ page = fw_priv->pages[fw_priv->nr_pages - 1];
+ xz_buf.out = kmap(page);
+ xz_buf.out_pos = 0;
+ xz_buf.out_size = PAGE_SIZE;
+ xz_ret = xz_dec_run(xz_dec, &xz_buf);
+ kunmap(page);
+ fw_priv->size += xz_buf.out_pos;
+ /* partial decompression means either end or error */
+ if (xz_buf.out_pos != PAGE_SIZE)
+ break;
+ } while (xz_ret == XZ_OK);
+
+ err = fw_decompress_xz_error(dev, xz_ret);
+ if (!err)
+ err = fw_map_paged_buf(fw_priv);
+
+ out:
+ xz_dec_end(xz_dec);
+ return err;
+}
+
+static int fw_decompress_xz(struct device *dev, struct fw_priv *fw_priv,
+ size_t in_size, const void *in_buffer)
+{
+ /* if the buffer is pre-allocated, we can perform in single-shot mode */
+ if (fw_priv->data)
+ return fw_decompress_xz_single(dev, fw_priv, in_size, in_buffer);
+ else
+ return fw_decompress_xz_pages(dev, fw_priv, in_size, in_buffer);
+}
+#endif /* CONFIG_FW_LOADER_COMPRESS */
+
/* direct firmware loading support */
static char fw_path_para[256];
static const char * const fw_path[] = {
@@ -354,7 +454,12 @@ module_param_string(path, fw_path_para, sizeof(fw_path_para), 0644);
MODULE_PARM_DESC(path, "customized firmware image search path with a higher priority than default path");

static int
-fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv)
+fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv,
+ const char *suffix,
+ int (*decompress)(struct device *dev,
+ struct fw_priv *fw_priv,
+ size_t in_size,
+ const void *in_buffer))
{
loff_t size;
int i, len;
@@ -362,9 +467,11 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv)
char *path;
enum kernel_read_file_id id = READING_FIRMWARE;
size_t msize = INT_MAX;
+ void *buffer = NULL;

/* Already populated data member means we're loading into a buffer */
- if (fw_priv->data) {
+ if (!decompress && fw_priv->data) {
+ buffer = fw_priv->data;
id = READING_FIRMWARE_PREALLOC_BUFFER;
msize = fw_priv->allocated_size;
}
@@ -378,15 +485,15 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv)
if (!fw_path[i][0])
continue;

- len = snprintf(path, PATH_MAX, "%s/%s",
- fw_path[i], fw_priv->fw_name);
+ len = snprintf(path, PATH_MAX, "%s/%s%s",
+ fw_path[i], fw_priv->fw_name, suffix);
if (len >= PATH_MAX) {
rc = -ENAMETOOLONG;
break;
}

fw_priv->size = 0;
- rc = kernel_read_file_from_path(path, &fw_priv->data, &size,
+ rc = kernel_read_file_from_path(path, &buffer, &size,
msize, id);
if (rc) {
if (rc != -ENOENT)
@@ -397,8 +504,24 @@ fw_get_filesystem_firmware(struct device *device, struct fw_priv *fw_priv)
path);
continue;
}
- dev_dbg(device, "direct-loading %s\n", fw_priv->fw_name);
- fw_priv->size = size;
+ if (decompress) {
+ dev_dbg(device, "f/w decompressing %s\n",
+ fw_priv->fw_name);
+ rc = decompress(device, fw_priv, size, buffer);
+ /* discard the superfluous original content */
+ vfree(buffer);
+ buffer = NULL;
+ if (rc) {
+ fw_free_paged_buf(fw_priv);
+ continue;
+ }
+ } else {
+ dev_dbg(device, "direct-loading %s\n",
+ fw_priv->fw_name);
+ if (!fw_priv->data)
+ fw_priv->data = buffer;
+ fw_priv->size = size;
+ }
fw_state_done(fw_priv);
break;
}
@@ -645,7 +768,13 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
if (ret <= 0) /* error or already assigned */
goto out;

- ret = fw_get_filesystem_firmware(device, fw->priv);
+ ret = fw_get_filesystem_firmware(device, fw->priv, "", NULL);
+#ifdef CONFIG_FW_LOADER_COMPRESS
+ if (ret == -ENOENT)
+ ret = fw_get_filesystem_firmware(device, fw->priv, ".xz",
+ fw_decompress_xz);
+#endif
+
if (ret) {
if (!(opt_flags & FW_OPT_NO_WARN))
dev_warn(device,
--
2.16.4
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