Merge tag 'pstore-v4.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull pstore updates from Kees Cook:
 "This cycle was almost entirely improvements to the pstore compression
  options, noted below:

   - Add lz4hc and 842 to pstore compression options (Geliang Tang)

   - Refactor to use crypto compression API (Geliang Tang)

   - Fix up Kconfig dependencies for compression (Arnd Bergmann)

   - Allow for run-time compression selection

   - Remove stack VLA usage"

* tag 'pstore-v4.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  pstore: fix crypto dependencies
  pstore: Use crypto compress API
  pstore/ram: Do not use stack VLA for parity workspace
  pstore: Select compression at runtime
  pstore: Avoid size casts for 842 compression
  pstore: Add lz4hc and 842 compression support

fs/pstore/Kconfig

 config PSTORE
 	tristate "Persistent store support"
+	select CRYPTO if PSTORE_COMPRESS
 	default n
 	help
 	   This option enables generic access to platform level
@@ -12,35 +13,89 @@ 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.
-
-config PSTORE_ZLIB_COMPRESS
-        bool "ZLIB"
-        select ZLIB_DEFLATE
-        select ZLIB_INFLATE
-        help
-          This option enables ZLIB compression algorithm support.
+config PSTORE_DEFLATE_COMPRESS
+	tristate "DEFLATE (ZLIB) compression"
+	default y
+	depends on PSTORE
+	select CRYPTO_DEFLATE
+	help
+	  This option enables DEFLATE (also known as ZLIB) compression
+	  algorithm support.
 
 config PSTORE_LZO_COMPRESS
-        bool "LZO"
-        select LZO_COMPRESS
-        select LZO_DECOMPRESS
-        help
-          This option enables LZO compression algorithm support.
+	tristate "LZO compression"
+	depends on PSTORE
+	select CRYPTO_LZO
+	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.
+	tristate "LZ4 compression"
+	depends on PSTORE
+	select CRYPTO_LZ4
+	help
+	  This option enables LZ4 compression algorithm support.
+
+config PSTORE_LZ4HC_COMPRESS
+	tristate "LZ4HC compression"
+	depends on PSTORE
+	select CRYPTO_LZ4HC
+	help
+	  This option enables LZ4HC (high compression) mode algorithm.
+
+config PSTORE_842_COMPRESS
+	bool "842 compression"
+	depends on PSTORE
+	select CRYPTO_842
+	help
+	  This option enables 842 compression algorithm support.
+
+config PSTORE_COMPRESS
+	def_bool y
+	depends on PSTORE
+	depends on PSTORE_DEFLATE_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:
+	  deflate, lzo, lz4, lz4hc and 842.
+
+	  The default compression algorithm is deflate.
+
+	config PSTORE_DEFLATE_COMPRESS_DEFAULT
+		bool "deflate" if PSTORE_DEFLATE_COMPRESS
+
+	config PSTORE_LZO_COMPRESS_DEFAULT
+		bool "lzo" if PSTORE_LZO_COMPRESS
+
+	config PSTORE_LZ4_COMPRESS_DEFAULT
+		bool "lz4" if PSTORE_LZ4_COMPRESS
+
+	config PSTORE_LZ4HC_COMPRESS_DEFAULT
+		bool "lz4hc" if PSTORE_LZ4HC_COMPRESS
+
+	config PSTORE_842_COMPRESS_DEFAULT
+		bool "842" if PSTORE_842_COMPRESS
+
 endchoice
 
+config PSTORE_COMPRESS_DEFAULT
+	string
+	depends on PSTORE_COMPRESS
+	default "deflate" if PSTORE_DEFLATE_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

fs/pstore/inode.c

@@ -486,6 +486,8 @@ static int __init init_pstore_fs(void)
 {
 	int err;
 
+	pstore_choose_compression();
+
 	/* Create a convenient mount point for people to access pstore */
 	err = sysfs_create_mount_point(fs_kobj, "pstore");
 	if (err)

fs/pstore/internal.h

@@ -37,4 +37,7 @@ extern bool	pstore_is_mounted(void);
 extern void	pstore_record_init(struct pstore_record *record,
 				   struct pstore_info *psi);
 
+/* Called during module_init() */
+extern void __init pstore_choose_compression(void);
+
 #endif

fs/pstore/ram.c

@@ -938,7 +938,7 @@ static int __init ramoops_init(void)
 	ramoops_register_dummy();
 	return platform_driver_register(&ramoops_driver);
 }
-postcore_initcall(ramoops_init);
+late_initcall(ramoops_init);
 
 static void __exit ramoops_exit(void)
 {

fs/pstore/ram_core.c

@@ -98,24 +98,23 @@ static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
 	uint8_t *data, size_t len, uint8_t *ecc)
 {
 	int i;
-	uint16_t par[prz->ecc_info.ecc_size];
 
 	/* Initialize the parity buffer */
-	memset(par, 0, sizeof(par));
-	encode_rs8(prz->rs_decoder, data, len, par, 0);
+	memset(prz->ecc_info.par, 0,
+	       prz->ecc_info.ecc_size * sizeof(prz->ecc_info.par[0]));
+	encode_rs8(prz->rs_decoder, data, len, prz->ecc_info.par, 0);
 	for (i = 0; i < prz->ecc_info.ecc_size; i++)
-		ecc[i] = par[i];
+		ecc[i] = prz->ecc_info.par[i];
 }
 
 static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
 	void *data, size_t len, uint8_t *ecc)
 {
 	int i;
-	uint16_t par[prz->ecc_info.ecc_size];
 
 	for (i = 0; i < prz->ecc_info.ecc_size; i++)
-		par[i] = ecc[i];
-	return decode_rs8(prz->rs_decoder, data, par, len,
+		prz->ecc_info.par[i] = ecc[i];
+	return decode_rs8(prz->rs_decoder, data, prz->ecc_info.par, len,
 				NULL, 0, NULL, 0, NULL);
 }
 
@@ -228,6 +227,15 @@ static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
 		return -EINVAL;
 	}
 
+	/* allocate workspace instead of using stack VLA */
+	prz->ecc_info.par = kmalloc_array(prz->ecc_info.ecc_size,
+					  sizeof(*prz->ecc_info.par),
+					  GFP_KERNEL);
+	if (!prz->ecc_info.par) {
+		pr_err("cannot allocate ECC parity workspace\n");
+		return -ENOMEM;
+	}
+
 	prz->corrected_bytes = 0;
 	prz->bad_blocks = 0;
 
@@ -514,6 +522,13 @@ void persistent_ram_free(struct persistent_ram_zone *prz)
 		}
 		prz->vaddr = NULL;
 	}
+	if (prz->rs_decoder) {
+		free_rs(prz->rs_decoder);
+		prz->rs_decoder = NULL;
+	}
+	kfree(prz->ecc_info.par);
+	prz->ecc_info.par = NULL;
+
 	persistent_ram_free_old(prz);
 	kfree(prz);
 }

include/linux/pstore_ram.h

@@ -39,6 +39,7 @@ struct persistent_ram_ecc_info {
 	int ecc_size;
 	int symsize;
 	int poly;
+	uint16_t *par;
 };
 
 struct persistent_ram_zone {