[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <1431551151-19124-4-git-send-email-toshi.kani@hp.com>
Date: Wed, 13 May 2015 15:05:44 -0600
From: Toshi Kani <toshi.kani@...com>
To: hpa@...or.com, tglx@...utronix.de, mingo@...hat.com,
akpm@...ux-foundation.org, arnd@...db.de
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org, x86@...nel.org,
linux-nvdimm@...ts.01.org, jgross@...e.com,
stefan.bader@...onical.com, luto@...capital.net, hmh@....eng.br,
yigal@...xistor.com, konrad.wilk@...cle.com, Elliott@...com,
mcgrof@...e.com, hch@....de, Toshi Kani <toshi.kani@...com>
Subject: [PATCH v9 3/10] x86, asm: Change is_new_memtype_allowed() for WT
__ioremap_caller() calls reserve_memtype() to set new_pcm
(existing map type if any), and then calls
is_new_memtype_allowed() to verify if converting to new_pcm
is allowed when pcm (request type) is different from new_pcm.
When WT is requested, the caller expects that writes are
ordered and uncached. Therefore, this patch changes
is_new_memtype_allowed() to disallow the following cases.
- If the request is WT, mapping type cannot be WB
- If the request is WT, mapping type cannot be WC
Signed-off-by: Toshi Kani <toshi.kani@...com>
---
arch/x86/include/asm/pgtable.h | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index fe57e7a..2562e30 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -398,11 +398,17 @@ static inline int is_new_memtype_allowed(u64 paddr, unsigned long size,
* requested memtype:
* - request is uncached, return cannot be write-back
* - request is write-combine, return cannot be write-back
+ * - request is write-through, return cannot be write-back
+ * - request is write-through, return cannot be write-combine
*/
if ((pcm == _PAGE_CACHE_MODE_UC_MINUS &&
new_pcm == _PAGE_CACHE_MODE_WB) ||
(pcm == _PAGE_CACHE_MODE_WC &&
- new_pcm == _PAGE_CACHE_MODE_WB)) {
+ new_pcm == _PAGE_CACHE_MODE_WB) ||
+ (pcm == _PAGE_CACHE_MODE_WT &&
+ new_pcm == _PAGE_CACHE_MODE_WB) ||
+ (pcm == _PAGE_CACHE_MODE_WT &&
+ new_pcm == _PAGE_CACHE_MODE_WC)) {
return 0;
}
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists