init: add support for zstd compressed modules

Signed-off-by: Piotr Gorski <lucjan.lucjanov@gmail.com>

Makefile

@@ -1043,8 +1043,8 @@ endif # INSTALL_MOD_STRIP
 export mod_strip_cmd
 
 # CONFIG_MODULE_COMPRESS, if defined, will cause module to be compressed
-# after they are installed in agreement with CONFIG_MODULE_COMPRESS_GZIP
-# or CONFIG_MODULE_COMPRESS_XZ.
+# after they are installed in agreement with CONFIG_MODULE_COMPRESS_GZIP,
+# CONFIG_MODULE_COMPRESS_XZ, or CONFIG_MODULE_COMPRESS_ZSTD.
 
 mod_compress_cmd = true
 ifdef CONFIG_MODULE_COMPRESS
@@ -1054,6 +1054,9 @@ ifdef CONFIG_MODULE_COMPRESS
   ifdef CONFIG_MODULE_COMPRESS_XZ
     mod_compress_cmd = $(XZ) -f
   endif # CONFIG_MODULE_COMPRESS_XZ
+  ifdef CONFIG_MODULE_COMPRESS_ZSTD
+    mod_compress_cmd = $(ZSTD) -T0 -20 --ultra --rm -f
+  endif
 endif # CONFIG_MODULE_COMPRESS
 export mod_compress_cmd
 

init/Kconfig

@@ -2214,8 +2214,8 @@ config MODULE_COMPRESS
 	bool "Compress modules on installation"
 	help
 
-	  Compresses kernel modules when 'make modules_install' is run; gzip or
-	  xz depending on "Compression algorithm" below.
+	  Compresses kernel modules when 'make modules_install' is run; gzip,
+	  xz, or zstd depending on "Compression algorithm" below.
 
 	  module-init-tools MAY support gzip, and kmod MAY support gzip and xz.
 
@@ -2237,14 +2237,17 @@ choice
 	  This determines which sort of compression will be used during
 	  'make modules_install'.
 
-	  GZIP (default) and XZ are supported.
+	  GZIP (default), XZ, and ZSTD are supported.
 
 config MODULE_COMPRESS_GZIP
 	bool "GZIP"
 
 config MODULE_COMPRESS_XZ
 	bool "XZ"
 
+config MODULE_COMPRESS_ZSTD
+	bool "ZSTD"
+
 endchoice
 
 config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS