[PATCH 1/5] firmware: Add the support for ZSTD-compressed firmware files

Takashi Iwai
2022-04-21T15:29:29Z

As the growing demand on ZSTD compressions, there have been requests
for the support of ZSTD-compressed firmware files, so here it is:
this patch extends the firmware loader code to allow loading ZSTD
files. The implementation is fairly straightforward, it just adds a
ZSTD decompression routine for the file expander. (And the code is
even simpler than XZ thanks to the ZSTD API that gives the original
decompressed size from the header.)

Tested-by: Piotr Gorski <lucjan.lucjanov@gmail.com>
Link: https://lore.kernel.org/all/20210127154939.13288-1-tiwai@suse.de/
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
drivers/base/firmware_loader/Kconfig | 24 ++++++---
drivers/base/firmware_loader/main.c | 76 ++++++++++++++++++++++++++--
2 files changed, 91 insertions(+), 9 deletions(-)

diff --git a/drivers/base/firmware_loader/Kconfig b/drivers/base/firmware_loader/Kconfig
index 38f3b66bf52b..08bb50451a96 100644
--- a/drivers/base/firmware_loader/Kconfig
+++ b/drivers/base/firmware_loader/Kconfig
@@ -159,21 +159,33 @@ config FW_LOADER_USER_HELPER_FALLBACK

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).
-
Compressed firmware support does not apply to firmware images
that are built into the kernel image (CONFIG_EXTRA_FIRMWARE).

+if FW_LOADER_COMPRESS
+config FW_LOADER_COMPRESS_XZ
+ bool "Enable XZ-compressed firmware support"
+ select FW_LOADER_PAGED_BUF
+ select XZ_DEC
+ help
+ This option adds the support for XZ-compressed files.
+ The files have to be compressed with either none or crc32
+ integrity check type (pass "-C crc32" option to xz command).
+
+config FW_LOADER_COMPRESS_ZSTD
+ bool "Enable ZSTD-compressed firmware support"
+ select ZSTD_DECOMPRESS
+ help
+ This option adds the support for ZSTD-compressed files.
+
+endif # FW_LOADER_COMPRESS
+
config FW_CACHE
bool "Enable firmware caching during suspend"
depends on PM_SLEEP
diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index 94d1789a233e..74830aeec7f6 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -35,6 +35,7 @@
#include <linux/syscore_ops.h>
#include <linux/reboot.h>
#include <linux/security.h>
+#include <linux/zstd.h>
#include <linux/xz.h>

#include <generated/utsrelease.h>
@@ -304,10 +305,74 @@ int fw_map_paged_buf(struct fw_priv *fw_priv)
}
#endif

+/*
+ * ZSTD-compressed firmware support
+ */
+#ifdef CONFIG_FW_LOADER_COMPRESS_ZSTD
+static int fw_decompress_zstd(struct device *dev, struct fw_priv *fw_priv,
+ size_t in_size, const void *in_buffer)
+{
+ size_t len, out_size, workspace_size;
+ void *workspace, *out_buf;
+ zstd_dctx *ctx;
+ int err;
+
+ if (fw_priv->allocated_size) {
+ out_size = fw_priv->allocated_size;
+ out_buf = fw_priv->data;
+ } else {
+ zstd_frame_header params;
+
+ if (zstd_get_frame_header(&params, in_buffer, in_size) ||
+ params.frameContentSize == ZSTD_CONTENTSIZE_UNKNOWN) {
+ dev_dbg(dev, "%s: invalid zstd header\n", __func__);
+ return -EINVAL;
+ }
+ out_size = params.frameContentSize;
+ out_buf = vzalloc(out_size);
+ if (!out_buf)
+ return -ENOMEM;
+ }
+
+ workspace_size = zstd_dctx_workspace_bound();
+ workspace = kvzalloc(workspace_size, GFP_KERNEL);
+ if (!workspace) {
+ err = -ENOMEM;
+ goto error;
+ }
+
+ ctx = zstd_init_dctx(workspace, workspace_size);
+ if (!ctx) {
+ dev_dbg(dev, "%s: failed to initialize context\n", __func__);
+ err = -EINVAL;
+ goto error;
+ }
+
+ len = zstd_decompress_dctx(ctx, out_buf, out_size, in_buffer, in_size);
+ if (zstd_is_error(len)) {
+ dev_dbg(dev, "%s: failed to decompress: %d\n", __func__,
+ zstd_get_error_code(len));
+ err = -EINVAL;
+ goto error;
+ }
+
+ if (!fw_priv->allocated_size)
+ fw_priv->data = out_buf;
+ fw_priv->size = len;
+ err = 0;
+
+ error:
+ kvfree(workspace);
+ if (err && !fw_priv->allocated_size)
+ vfree(out_buf);
+ return err;
+}
+#endif /* CONFIG_FW_LOADER_COMPRESS_ZSTD */
+
/*
* XZ-compressed firmware support
*/
-#ifdef CONFIG_FW_LOADER_COMPRESS
+#ifdef CONFIG_FW_LOADER_COMPRESS_XZ
/* show an error and return the standard error code */
static int fw_decompress_xz_error(struct device *dev, enum xz_ret xz_ret)
{
@@ -401,7 +466,7 @@ 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);
}
-#endif /* CONFIG_FW_LOADER_COMPRESS */
+#endif /* CONFIG_FW_LOADER_COMPRESS_XZ */

/* direct firmware loading support */
static char fw_path_para[256];
@@ -757,7 +822,12 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
if (!(opt_flags & FW_OPT_PARTIAL))
nondirect = true;

-#ifdef CONFIG_FW_LOADER_COMPRESS
+#ifdef CONFIG_FW_LOADER_COMPRESS_ZSTD
+ if (ret == -ENOENT && nondirect)
+ ret = fw_get_filesystem_firmware(device, fw->priv, ".zst",
+ fw_decompress_zstd);
+#endif
+#ifdef CONFIG_FW_LOADER_COMPRESS_XZ
if (ret == -ENOENT && nondirect)
ret = fw_get_filesystem_firmware(device, fw->priv, ".xz",
fw_decompress_xz);
--
2.31.1