pstore: Select compression at runtime

To allow for easier build test coverage and run-time testing, this allows
multiple compression algorithms to be built into pstore. Still only one
is supported to operate at a time (which can be selected at build time
or at boot time, similar to how LSMs are selected).

Signed-off-by: Kees Cook <keescook@chromium.org>

1 files changed, 67 insertions, 29 deletions

diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
index 898abafea7a5..e4e22026c7a1 100644
--- a/fs/pstore/Kconfig
+++ b/fs/pstore/Kconfig
@@ -12,55 +12,93 @@ config PSTORE
 	   If you don't have a platform persistent store driver,
 	   say N.
 
-choice
-        prompt "Choose compression algorithm"
-        depends on PSTORE
-        default PSTORE_ZLIB_COMPRESS
-        help
-          This option chooses compression algorithm.
-
-	  Currently, pstore has support for 5 compression algorithms:
-	  zlib, lzo, lz4, lz4hc and 842.
-
-	  The default compression algorithm is zlib.
-
 config PSTORE_ZLIB_COMPRESS
-        bool "ZLIB"
-        select ZLIB_DEFLATE
-        select ZLIB_INFLATE
-        help
-          This option enables ZLIB compression algorithm support.
+	bool "ZLIB compression"
+	default y
+	depends on PSTORE
+	select ZLIB_DEFLATE
+	select ZLIB_INFLATE
+	help
+	  This option enables ZLIB compression algorithm support.
 
 config PSTORE_LZO_COMPRESS
-        bool "LZO"
-        select LZO_COMPRESS
-        select LZO_DECOMPRESS
-        help
-          This option enables LZO compression algorithm support.
+	bool "LZO compression"
+	depends on PSTORE
+	select LZO_COMPRESS
+	select LZO_DECOMPRESS
+	help
+	  This option enables LZO compression algorithm support.
 
 config PSTORE_LZ4_COMPRESS
-        bool "LZ4"
-        select LZ4_COMPRESS
-        select LZ4_DECOMPRESS
-        help
-          This option enables LZ4 compression algorithm support.
+	bool "LZ4 compression"
+	depends on PSTORE
+	select LZ4_COMPRESS
+	select LZ4_DECOMPRESS
+	help
+	  This option enables LZ4 compression algorithm support.
 
 config PSTORE_LZ4HC_COMPRESS
-	bool "LZ4HC"
+	bool "LZ4HC compression"
+	depends on PSTORE
 	select LZ4HC_COMPRESS
 	select LZ4_DECOMPRESS
 	help
 	  This option enables LZ4HC (high compression) mode algorithm.
 
 config PSTORE_842_COMPRESS
-	bool "842"
+	bool "842 compression"
+	depends on PSTORE
 	select 842_COMPRESS
 	select 842_DECOMPRESS
 	help
 	  This option enables 842 compression algorithm support.
 
+config PSTORE_COMPRESS
+	def_bool y
+	depends on PSTORE
+	depends on PSTORE_ZLIB_COMPRESS || PSTORE_LZO_COMPRESS ||	\
+		   PSTORE_LZ4_COMPRESS || PSTORE_LZ4HC_COMPRESS ||	\
+		   PSTORE_842_COMPRESS
+
+choice
+	prompt "Default pstore compression algorithm"
+	depends on PSTORE_COMPRESS
+	help
+	  This option chooses the default active compression algorithm.
+	  This change be changed at boot with "pstore.compress=..." on
+	  the kernel command line.
+
+	  Currently, pstore has support for 5 compression algorithms:
+	  zlib, lzo, lz4, lz4hc and 842.
+
+	  The default compression algorithm is zlib.
+
+	config PSTORE_ZLIB_COMPRESS_DEFAULT
+		bool "zlib" if PSTORE_ZLIB_COMPRESS=y
+
+	config PSTORE_LZO_COMPRESS_DEFAULT
+		bool "lzo" if PSTORE_LZO_COMPRESS=y
+
+	config PSTORE_LZ4_COMPRESS_DEFAULT
+		bool "lz4" if PSTORE_LZ4_COMPRESS=y
+
+	config PSTORE_LZ4HC_COMPRESS_DEFAULT
+		bool "lz4hc" if PSTORE_LZ4HC_COMPRESS=y
+
+	config PSTORE_842_COMPRESS_DEFAULT
+		bool "842" if PSTORE_842_COMPRESS=y
+
 endchoice
 
+config PSTORE_COMPRESS_DEFAULT
+	string
+	depends on PSTORE_COMPRESS
+	default "zlib" if PSTORE_ZLIB_COMPRESS_DEFAULT
+	default "lzo" if PSTORE_LZO_COMPRESS_DEFAULT
+	default "lz4" if PSTORE_LZ4_COMPRESS_DEFAULT
+	default "lz4hc" if PSTORE_LZ4HC_COMPRESS_DEFAULT
+	default "842" if PSTORE_842_COMPRESS_DEFAULT
+
 config PSTORE_CONSOLE
 	bool "Log kernel console messages"
 	depends on PSTORE