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authorToshi Kani <toshi.kani@hp.com>2015-06-04 18:55:13 +0200
committerIngo Molnar <mingo@kernel.org>2015-06-07 15:28:55 +0200
commit0d69bdff451a10aa48f80509e8bf18fb24683c06 (patch)
tree2bbc125e72acc87da9e1fb3dd26f164ea8b43954 /arch/x86/mm/pat.c
parentd79a40caf8e15a2a15ecdefdc9d05865d4f37baa (diff)
x86/mm/pat: Change reserve_memtype() for Write-Through type
When a target range is in RAM, reserve_ram_pages_type() verifies the requested type. Change it to fail WT and WP requests with -EINVAL since set_page_memtype() is limited to handle three types: WB, WC and UC-. Signed-off-by: Toshi Kani <toshi.kani@hp.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Elliott@hp.com Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: arnd@arndb.de Cc: hch@lst.de Cc: hmh@hmh.eng.br Cc: jgross@suse.com Cc: konrad.wilk@oracle.com Cc: linux-mm <linux-mm@kvack.org> Cc: linux-nvdimm@lists.01.org Cc: stefan.bader@canonical.com Cc: yigal@plexistor.com Link: http://lkml.kernel.org/r/1433436928-31903-6-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/mm/pat.c')
-rw-r--r--arch/x86/mm/pat.c17
1 files changed, 14 insertions, 3 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 59ab1a0fe21b..6311193fd1a2 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -401,9 +401,12 @@ static int pat_pagerange_is_ram(resource_size_t start, resource_size_t end)
/*
* For RAM pages, we use page flags to mark the pages with appropriate type.
- * Here we do two pass:
- * - Find the memtype of all the pages in the range, look for any conflicts
- * - In case of no conflicts, set the new memtype for pages in the range
+ * The page flags are limited to three types, WB, WC and UC-. WT and WP requests
+ * fail with -EINVAL, and UC gets redirected to UC-.
+ *
+ * Here we do two passes:
+ * - Find the memtype of all the pages in the range, look for any conflicts.
+ * - In case of no conflicts, set the new memtype for pages in the range.
*/
static int reserve_ram_pages_type(u64 start, u64 end,
enum page_cache_mode req_type,
@@ -412,6 +415,13 @@ static int reserve_ram_pages_type(u64 start, u64 end,
struct page *page;
u64 pfn;
+ if ((req_type == _PAGE_CACHE_MODE_WT) ||
+ (req_type == _PAGE_CACHE_MODE_WP)) {
+ if (new_type)
+ *new_type = _PAGE_CACHE_MODE_UC_MINUS;
+ return -EINVAL;
+ }
+
if (req_type == _PAGE_CACHE_MODE_UC) {
/* We do not support strong UC */
WARN_ON_ONCE(1);
@@ -461,6 +471,7 @@ static int free_ram_pages_type(u64 start, u64 end)
* - _PAGE_CACHE_MODE_WC
* - _PAGE_CACHE_MODE_UC_MINUS
* - _PAGE_CACHE_MODE_UC
+ * - _PAGE_CACHE_MODE_WT
*
* If new_type is NULL, function will return an error if it cannot reserve the
* region with req_type. If new_type is non-NULL, function will return