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Message-Id: <20200821.143553.1830499839841272707.rene@exactcode.com>
Date: Fri, 21 Aug 2020 14:35:53 +0200 (CEST)
From: Rene Rebe <rene@...ctcode.com>
To: linux-kernel@...r.kernel.org
Subject: [PATCH] zstd compressed firmware loading
Now with zstd compressed kernel & initrd upstream, we would rather
compress everything with one type of compressor, so I added support
for zstd compressed firmware loading, too.
Tested on x86-64, sparc64 and mips64.
Signed-off-by: René Rebe <rene@...ctcode.de>
diff --git a/drivers/base/firmware_loader/Kconfig b/drivers/base/firmware_loader/Kconfig
index 5b24f3959255..30d440bec257 100644
--- a/drivers/base/firmware_loader/Kconfig
+++ b/drivers/base/firmware_loader/Kconfig
@@ -169,6 +169,16 @@ config FW_LOADER_COMPRESS
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 FW_LOADER_PAGED_BUF
+ select ZSTD_DECOMPRESS
+ help
+ This option enables the support for loading Zstd 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.
+
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 9da0c9d5f538..5deb73dbe81e 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -33,7 +33,9 @@
#include <linux/syscore_ops.h>
#include <linux/reboot.h>
#include <linux/security.h>
+#include <linux/decompress/mm.h>
#include <linux/xz.h>
+#include <linux/zstd.h>
#include <generated/utsrelease.h>
@@ -435,6 +437,140 @@ static int fw_decompress_xz(struct device *dev, struct fw_priv *fw_priv,
}
#endif /* CONFIG_FW_LOADER_COMPRESS */
+/*
+ * Zstd-compressed firmware support
+ */
+#ifdef CONFIG_FW_LOADER_COMPRESS_ZSTD
+/* show an error and return the standard error code */
+static int handle_zstd_error(size_t ret)
+{
+ const int err = ZSTD_getErrorCode(ret);
+
+ if (!ZSTD_isError(ret))
+ return 0;
+
+ switch (err) {
+ case ZSTD_error_memory_allocation:
+ printk("ZSTD decompressor ran out of memory");
+ break;
+ case ZSTD_error_prefix_unknown:
+ printk("Input is not in the ZSTD format (wrong magic bytes)");
+ break;
+ case ZSTD_error_dstSize_tooSmall:
+ case ZSTD_error_corruption_detected:
+ case ZSTD_error_checksum_wrong:
+ printk("ZSTD-compressed data is corrupt");
+ break;
+ default:
+ printk("ZSTD-compressed data is probably corrupt");
+ break;
+ }
+ return -1;
+}
+
+/* single-shot decompression onto the pre-allocated buffer */
+static int fw_decompress_zstd_single(struct device *dev, struct fw_priv *fw_priv,
+ size_t in_size, const void *in_buffer)
+{
+ const size_t wksp_size = ZSTD_DCtxWorkspaceBound();
+ void *wksp = large_malloc(wksp_size);
+ ZSTD_DCtx *dctx = ZSTD_initDCtx(wksp, wksp_size);
+ int err;
+ size_t ret;
+
+ printk("zstd_single\n");
+
+ if (dctx == NULL) {
+ dev_warn(dev, "Out of memory while allocating ZSTD_DCtx");
+ err = -1;
+ goto out;
+ }
+ /* Find out how large the frame actually is, there may be junk at
+ * the end of the frame that ZSTD_decompressDCtx() can't handle.
+ */
+ ret = ZSTD_findFrameCompressedSize(in_buffer, in_size);
+ err = handle_zstd_error(ret);
+ if (err)
+ goto out;
+ in_size = (long)ret;
+
+ ret = ZSTD_decompressDCtx(dctx, fw_priv->data, fw_priv->allocated_size, in_buffer, in_size);
+ err = handle_zstd_error(ret);
+ if (err)
+ goto out;
+
+ fw_priv->size = ret;
+
+out:
+ if (wksp != NULL)
+ large_free(wksp);
+ return err;
+}
+
+/* decompression on paged buffer and map it */
+static int fw_decompress_zstd_pages(struct device *dev, struct fw_priv *fw_priv,
+ size_t in_size, const void *in_buffer)
+{
+#if 0
+ struct zstd_dec *zstd_dec;
+ struct zstd_buf zstd_buf;
+ enum zstd_ret zstd_ret;
+ struct page *page;
+ int err = 0;
+
+ printk("zstd_pages\n");
+
+ zstd_dec = zstd_dec_init(ZSTD_DYNALLOC, (u32)-1);
+ if (!zstd_dec)
+ return -ENOMEM;
+
+ zstd_buf.in_size = in_size;
+ zstd_buf.in = in_buffer;
+ zstd_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];
+ zstd_buf.out = kmap(page);
+ zstd_buf.out_pos = 0;
+ zstd_buf.out_size = PAGE_SIZE;
+ zstd_ret = zstd_dec_run(zstd_dec, &zstd_buf);
+ kunmap(page);
+ fw_priv->size += zstd_buf.out_pos;
+ /* partial decompression means either end or error */
+ if (zstd_buf.out_pos != PAGE_SIZE)
+ break;
+ } while (zstd_ret == ZSTD_OK);
+
+ err = fw_decompress_zstd_error(dev, zstd_ret);
+ if (!err)
+ err = fw_map_paged_buf(fw_priv);
+
+ out:
+ zstd_dec_end(zstd_dec);
+ return err;
+#endif
+ return -ENOMEM;
+}
+
+static int fw_decompress_zstd(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_zstd_single(dev, fw_priv, in_size, in_buffer);
+ else
+ return fw_decompress_zstd_pages(dev, fw_priv, in_size, in_buffer);
+}
+#endif /* CONFIG_FW_LOADER_COMPRESS_ZSTD */
+
/* direct firmware loading support */
static char fw_path_para[256];
static const char * const fw_path[] = {
@@ -773,6 +909,11 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
ret = fw_get_filesystem_firmware(device, fw->priv, ".xz",
fw_decompress_xz);
#endif
+#ifdef CONFIG_FW_LOADER_COMPRESS_ZSTD
+ if (ret == -ENOENT)
+ ret = fw_get_filesystem_firmware(device, fw->priv, ".zst",
+ fw_decompress_zstd);
+#endif
if (ret == -ENOENT)
ret = firmware_fallback_platform(fw->priv, opt_flags);
--
René Rebe, ExactCODE GmbH, Lietzenburger Str. 42, DE-10789 Berlin
https://exactcode.com | https://t2sde.org | https://rene.rebe.de
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