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Commit 0d69bdff authored by Toshi Kani's avatar Toshi Kani Committed by Ingo Molnar
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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: default avatarToshi Kani <toshi.kani@hp.com>
Signed-off-by: default avatarBorislav 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: default avatarIngo Molnar <mingo@kernel.org>
parent d79a40ca

arch/x86/mm/pat.c

+14 −3
Original line number Diff line number Diff line
@@ -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