From mboxrd@z Thu Jan 1 00:00:00 1970 From: robherring2@gmail.com (Rob Herring) Date: Tue, 9 Apr 2013 22:08:15 -0500 Subject: [RFC PATCH 1/3] pstore-ram: use write-combine mappings Message-ID: <1365563297-12480-1-git-send-email-robherring2@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Rob Herring Atomic operations are undefined behavior on ARM for device or strongly ordered memory types. So use write-combine variants for mappings. This corresponds to normal, non-cacheable memory on ARM. For many other architectures, this change should not change the mapping type. Signed-off-by: Rob Herring Cc: Anton Vorontsov Cc: Colin Cross Cc: Kees Cook Cc: Tony Luck Cc: linux-kernel at vger.kernel.org --- fs/pstore/ram_core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c index 0306303..e126d9f 100644 --- a/fs/pstore/ram_core.c +++ b/fs/pstore/ram_core.c @@ -337,7 +337,7 @@ 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); + prot = pgprot_writecombine(PAGE_KERNEL); pages = kmalloc(sizeof(struct page *) * page_count, GFP_KERNEL); if (!pages) { @@ -364,7 +364,7 @@ static void *persistent_ram_iomap(phys_addr_t start, size_t size) return NULL; } - return ioremap(start, size); + return ioremap_wc(start, size); } static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size, -- 1.7.10.4