pstore/ram: Make ECC size configurable

This is now pretty straightforward: instead of using bool, just pass
an integer. For backwards compatibility ramoops.ecc=1 means 16 bytes
ECC (using 1 byte for ECC isn't much of use anyway).

Suggested-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/pstore/ram.c

@@ -63,7 +63,9 @@ MODULE_PARM_DESC(dump_oops,
 static int ramoops_ecc;
 module_param_named(ecc, ramoops_ecc, int, 0600);
 MODULE_PARM_DESC(ramoops_ecc,
-		"set to 1 to enable ECC support");
+		"if non-zero, the option enables ECC support and specifies "
+		"ECC buffer size in bytes (1 is a special value, means 16 "
+		"bytes ECC)");
 
 struct ramoops_context {
 	struct persistent_ram_zone **przs;
@@ -73,7 +75,7 @@ struct ramoops_context {
 	size_t record_size;
 	size_t console_size;
 	int dump_oops;
-	bool ecc;
+	int ecc_size;
 	unsigned int max_dump_cnt;
 	unsigned int dump_write_cnt;
 	unsigned int dump_read_cnt;
@@ -288,7 +290,7 @@ static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
 	for (i = 0; i < cxt->max_dump_cnt; i++) {
 		size_t sz = cxt->record_size;
 
-		cxt->przs[i] = persistent_ram_new(*paddr, sz, cxt->ecc);
+		cxt->przs[i] = persistent_ram_new(*paddr, sz, cxt->ecc_size);
 		if (IS_ERR(cxt->przs[i])) {
 			err = PTR_ERR(cxt->przs[i]);
 			dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
@@ -314,7 +316,7 @@ static int ramoops_init_prz(struct device *dev, struct ramoops_context *cxt,
 	if (*paddr + sz > *paddr + cxt->size)
 		return -ENOMEM;
 
-	*prz = persistent_ram_new(*paddr, sz, cxt->ecc);
+	*prz = persistent_ram_new(*paddr, sz, cxt->ecc_size);
 	if (IS_ERR(*prz)) {
 		int err = PTR_ERR(*prz);
 
@@ -361,7 +363,7 @@ static int __devinit ramoops_probe(struct platform_device *pdev)
 	cxt->record_size = pdata->record_size;
 	cxt->console_size = pdata->console_size;
 	cxt->dump_oops = pdata->dump_oops;
-	cxt->ecc = pdata->ecc;
+	cxt->ecc_size = pdata->ecc_size;
 
 	paddr = cxt->phys_addr;
 
@@ -411,9 +413,9 @@ static int __devinit ramoops_probe(struct platform_device *pdev)
 	record_size = pdata->record_size;
 	dump_oops = pdata->dump_oops;
 
-	pr_info("attached 0x%lx@0x%llx, ecc: %s\n",
+	pr_info("attached 0x%lx@0x%llx, ecc: %d\n",
 		cxt->size, (unsigned long long)cxt->phys_addr,
-		ramoops_ecc ? "on" : "off");
+		cxt->ecc_size);
 
 	return 0;
 
@@ -478,7 +480,11 @@ static void ramoops_register_dummy(void)
 	dummy_data->record_size = record_size;
 	dummy_data->console_size = ramoops_console_size;
 	dummy_data->dump_oops = dump_oops;
-	dummy_data->ecc = ramoops_ecc;
+	/*
+	 * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
+	 * (using 1 byte for ECC isn't much of use anyway).
+	 */
+	dummy_data->ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
 
 	dummy = platform_device_register_data(NULL, "ramoops", -1,
 			dummy_data, sizeof(struct ramoops_platform_data));

fs/pstore/ram_core.c

@@ -171,7 +171,8 @@ static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
 	}
 }
 
-static int persistent_ram_init_ecc(struct persistent_ram_zone *prz)
+static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
+				   int ecc_size)
 {
 	int numerr;
 	struct persistent_ram_buffer *buffer = prz->buffer;
@@ -184,7 +185,7 @@ static int persistent_ram_init_ecc(struct persistent_ram_zone *prz)
 		return 0;
 
 	prz->ecc_block_size = 128;
-	prz->ecc_size = 16;
+	prz->ecc_size = ecc_size;
 
 	ecc_blocks = DIV_ROUND_UP(prz->buffer_size, prz->ecc_block_size);
 	ecc_total = (ecc_blocks + 1) * prz->ecc_size;
@@ -390,13 +391,13 @@ static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
 }
 
 static int __devinit persistent_ram_post_init(struct persistent_ram_zone *prz,
-					      bool ecc)
+					      int ecc_size)
 {
 	int ret;
 
-	prz->ecc = ecc;
+	prz->ecc = ecc_size;
 
-	ret = persistent_ram_init_ecc(prz);
+	ret = persistent_ram_init_ecc(prz, ecc_size);
 	if (ret)
 		return ret;
 
@@ -444,7 +445,7 @@ void persistent_ram_free(struct persistent_ram_zone *prz)
 
 struct persistent_ram_zone * __devinit persistent_ram_new(phys_addr_t start,
 							  size_t size,
-							  bool ecc)
+							  int ecc_size)
 {
 	struct persistent_ram_zone *prz;
 	int ret = -ENOMEM;
@@ -459,7 +460,7 @@ struct persistent_ram_zone * __devinit persistent_ram_new(phys_addr_t start,
 	if (ret)
 		goto err;
 
-	ret = persistent_ram_post_init(prz, ecc);
+	ret = persistent_ram_post_init(prz, ecc_size);
 	if (ret)
 		goto err;
 

include/linux/pstore_ram.h

@@ -48,7 +48,7 @@ struct persistent_ram_zone {
 
 struct persistent_ram_zone * __devinit persistent_ram_new(phys_addr_t start,
 							  size_t size,
-							  bool ecc);
+							  int ecc_size);
 void persistent_ram_free(struct persistent_ram_zone *prz);
 void persistent_ram_zap(struct persistent_ram_zone *prz);
 
@@ -74,7 +74,7 @@ struct ramoops_platform_data {
 	unsigned long	record_size;
 	unsigned long	console_size;
 	int		dump_oops;
-	bool		ecc;
+	int		ecc_size;
 };
 
 #endif