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>

2 files changed, 22 insertions, 15 deletions

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 58b93fbd117e..b39aebbaeb89 100644
--- a/fs/pstore/ram.c
+++ b/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));
diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index 3f4d6e64f6d7..7e5a2a9154ca 100644
--- a/fs/pstore/ram_core.c
+++ b/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;