2 files changed, 33 insertions, 11 deletions

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index ec881b312700..2f389ce5023c 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -61,6 +61,11 @@ module_param(mem_size, ulong, 0400);
 MODULE_PARM_DESC(mem_size,
                 "size of reserved RAM used to store oops/panic logs");
 
+static unsigned int mem_type;
+module_param(mem_type, uint, 0600);
+MODULE_PARM_DESC(mem_type,
+                "set to 1 to try to use unbuffered memory (default 0)");
+
 static int dump_oops = 1;
 module_param(dump_oops, int, 0600);
 MODULE_PARM_DESC(dump_oops,
@@ -79,6 +84,7 @@ struct ramoops_context {
         struct persistent_ram_zone *fprz;
         phys_addr_t phys_addr;
         unsigned long size;
+        unsigned int memtype;
         size_t record_size;
         size_t console_size;
         size_t ftrace_size;
@@ -366,7 +372,8 @@ static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
                 size_t sz = cxt->record_size;
 
                 cxt->przs[i] = persistent_ram_new(*paddr, sz, 0,
-                                                  &cxt->ecc_info);
+                                                  &cxt->ecc_info,
+                                                  cxt->memtype);
                 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",
@@ -396,7 +403,7 @@ static int ramoops_init_prz(struct device *dev, struct ramoops_context *cxt,
                 return -ENOMEM;
         }
 
-        *prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info);
+        *prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info, cxt->memtype);
         if (IS_ERR(*prz)) {
                 int err = PTR_ERR(*prz);
 
@@ -443,6 +450,7 @@ static int ramoops_probe(struct platform_device *pdev)
 
         cxt->size = pdata->mem_size;
         cxt->phys_addr = pdata->mem_address;
+        cxt->memtype = pdata->mem_type;
         cxt->record_size = pdata->record_size;
         cxt->console_size = pdata->console_size;
         cxt->ftrace_size = pdata->ftrace_size;
@@ -572,6 +580,7 @@ static void ramoops_register_dummy(void)
 
         dummy_data->mem_size = mem_size;
         dummy_data->mem_address = mem_address;
+        dummy_data->mem_type = 0;
         dummy_data->record_size = record_size;
         dummy_data->console_size = ramoops_console_size;
         dummy_data->ftrace_size = ramoops_ftrace_size;
diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index 9d7b9a83699e..76c3f80efdfa 100644
--- a/fs/pstore/ram_core.c
+++ b/fs/pstore/ram_core.c
@@ -380,7 +380,8 @@ void persistent_ram_zap(struct persistent_ram_zone *prz)
         persistent_ram_update_header_ecc(prz);
 }
 
-static void *persistent_ram_vmap(phys_addr_t start, size_t size)
+static void *persistent_ram_vmap(phys_addr_t start, size_t size,
+                unsigned int memtype)
 {
         struct page **pages;
         phys_addr_t page_start;
@@ -392,7 +393,10 @@ static void *persistent_ram_vmap(phys_addr_t start, size_t size)
         page_start = start - offset_in_page(start);
         page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
 
-        prot = pgprot_noncached(PAGE_KERNEL);
+        if (memtype)
+                prot = pgprot_noncached(PAGE_KERNEL);
+        else
+                prot = pgprot_writecombine(PAGE_KERNEL);
 
         pages = kmalloc_array(page_count, sizeof(struct page *), GFP_KERNEL);
         if (!pages) {
@@ -411,8 +415,11 @@ static void *persistent_ram_vmap(phys_addr_t start, size_t size)
         return vaddr;
 }
 
-static void *persistent_ram_iomap(phys_addr_t start, size_t size)
+static void *persistent_ram_iomap(phys_addr_t start, size_t size,
+                unsigned int memtype)
 {
+        void *va;
+
         if (!request_mem_region(start, size, "persistent_ram")) {
                 pr_err("request mem region (0x%llx@0x%llx) failed\n",
                         (unsigned long long)size, (unsigned long long)start);
@@ -422,19 +429,24 @@ static void *persistent_ram_iomap(phys_addr_t start, size_t size)
         buffer_start_add = buffer_start_add_locked;
         buffer_size_add = buffer_size_add_locked;
 
-        return ioremap(start, size);
+        if (memtype)
+                va = ioremap(start, size);
+        else
+                va = ioremap_wc(start, size);
+
+        return va;
 }
 
 static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
-                struct persistent_ram_zone *prz)
+                struct persistent_ram_zone *prz, int memtype)
 {
         prz->paddr = start;
         prz->size = size;
 
         if (pfn_valid(start >> PAGE_SHIFT))
-                prz->vaddr = persistent_ram_vmap(start, size);
+                prz->vaddr = persistent_ram_vmap(start, size, memtype);
         else
-                prz->vaddr = persistent_ram_iomap(start, size);
+                prz->vaddr = persistent_ram_iomap(start, size, memtype);
 
         if (!prz->vaddr) {
                 pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
@@ -500,7 +512,8 @@ void persistent_ram_free(struct persistent_ram_zone *prz)
 }
 
 struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
-                        u32 sig, struct persistent_ram_ecc_info *ecc_info)
+                        u32 sig, struct persistent_ram_ecc_info *ecc_info,
+                        unsigned int memtype)
 {
         struct persistent_ram_zone *prz;
         int ret = -ENOMEM;
@@ -511,7 +524,7 @@ struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
                 goto err;
         }
 
-        ret = persistent_ram_buffer_map(start, size, prz);
+        ret = persistent_ram_buffer_map(start, size, prz, memtype);
         if (ret)
                 goto err;