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From: Toshi Kani <toshi.kani@hp.com>
To: hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com,
	akpm@linux-foundation.org, arnd@arndb.de
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	jgross@suse.com, stefan.bader@canonical.com, luto@amacapital.net,
	hmh@hmh.eng.br, yigal@plexistor.com, konrad.wilk@oracle.com,
	Elliott@hp.com, Toshi Kani <toshi.kani@hp.com>
Subject: [PATCH v8 3/7] x86, mm, asm-gen: Add ioremap_wt() for WT
Date: Tue, 24 Feb 2015 17:14:57 -0700	[thread overview]
Message-ID: <1424823301-30927-4-git-send-email-toshi.kani@hp.com> (raw)
In-Reply-To: <1424823301-30927-1-git-send-email-toshi.kani@hp.com>

This patch adds ioremap_wt() for creating WT mapping on x86.
It follows the same model as ioremap_wc() for multi-architecture
support.  ARCH_HAS_IOREMAP_WT is defined in the x86 version of
io.h to indicate that ioremap_wt() is implemented on x86.

Also update the PAT documentation file to cover ioremap_wt().

Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 Documentation/x86/pat.txt   |    4 +++-
 arch/x86/include/asm/io.h   |    2 ++
 arch/x86/mm/ioremap.c       |   24 ++++++++++++++++++++++++
 include/asm-generic/io.h    |    9 +++++++++
 include/asm-generic/iomap.h |    4 ++++
 5 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/Documentation/x86/pat.txt b/Documentation/x86/pat.txt
index cf08c9f..be7b8c2 100644
--- a/Documentation/x86/pat.txt
+++ b/Documentation/x86/pat.txt
@@ -12,7 +12,7 @@ virtual addresses.
 
 PAT allows for different types of memory attributes. The most commonly used
 ones that will be supported at this time are Write-back, Uncached,
-Write-combined and Uncached Minus.
+Write-combined, Write-through and Uncached Minus.
 
 
 PAT APIs
@@ -38,6 +38,8 @@ ioremap_nocache        |    --    |    UC-     |       UC-        |
                        |          |            |                  |
 ioremap_wc             |    --    |    --      |       WC         |
                        |          |            |                  |
+ioremap_wt             |    --    |    --      |       WT         |
+                       |          |            |                  |
 set_memory_uc          |    UC-   |    --      |       --         |
  set_memory_wb         |          |            |                  |
                        |          |            |                  |
diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index 34a5b93..81942ef 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -35,6 +35,7 @@
   */
 
 #define ARCH_HAS_IOREMAP_WC
+#define ARCH_HAS_IOREMAP_WT
 
 #include <linux/string.h>
 #include <linux/compiler.h>
@@ -320,6 +321,7 @@ extern void unxlate_dev_mem_ptr(phys_addr_t phys, void *addr);
 extern int ioremap_change_attr(unsigned long vaddr, unsigned long size,
 				enum page_cache_mode pcm);
 extern void __iomem *ioremap_wc(resource_size_t offset, unsigned long size);
+extern void __iomem *ioremap_wt(resource_size_t offset, unsigned long size);
 
 extern bool is_early_ioremap_ptep(pte_t *ptep);
 
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index fdf617c..4f794b2 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -167,6 +167,10 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
 		prot = __pgprot(pgprot_val(prot) |
 				cachemode2protval(_PAGE_CACHE_MODE_WC));
 		break;
+	case _PAGE_CACHE_MODE_WT:
+		prot = __pgprot(pgprot_val(prot) |
+				cachemode2protval(_PAGE_CACHE_MODE_WT));
+		break;
 	case _PAGE_CACHE_MODE_WB:
 		break;
 	}
@@ -261,6 +265,26 @@ void __iomem *ioremap_wc(resource_size_t phys_addr, unsigned long size)
 }
 EXPORT_SYMBOL(ioremap_wc);
 
+/**
+ * ioremap_wt	-	map memory into CPU space write through
+ * @phys_addr:	bus address of the memory
+ * @size:	size of the resource to map
+ *
+ * This version of ioremap ensures that the memory is marked write through.
+ * Write through stores data into memory while keeping the cache up-to-date.
+ *
+ * Must be freed with iounmap.
+ */
+void __iomem *ioremap_wt(resource_size_t phys_addr, unsigned long size)
+{
+	if (pat_enabled)
+		return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WT,
+					__builtin_return_address(0));
+	else
+		return ioremap_nocache(phys_addr, size);
+}
+EXPORT_SYMBOL(ioremap_wt);
+
 void __iomem *ioremap_cache(resource_size_t phys_addr, unsigned long size)
 {
 	return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WB,
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index 9db0423..bae62dc 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -777,8 +777,17 @@ static inline void __iomem *ioremap_wc(phys_addr_t offset, size_t size)
 }
 #endif
 
+#ifndef ioremap_wt
+#define ioremap_wt ioremap_wt
+static inline void __iomem *ioremap_wt(phys_addr_t offset, size_t size)
+{
+	return ioremap_nocache(offset, size);
+}
+#endif
+
 #ifndef iounmap
 #define iounmap iounmap
+
 static inline void iounmap(void __iomem *addr)
 {
 }
diff --git a/include/asm-generic/iomap.h b/include/asm-generic/iomap.h
index 1b41011..d8f8622 100644
--- a/include/asm-generic/iomap.h
+++ b/include/asm-generic/iomap.h
@@ -66,6 +66,10 @@ extern void ioport_unmap(void __iomem *);
 #define ioremap_wc ioremap_nocache
 #endif
 
+#ifndef ARCH_HAS_IOREMAP_WT
+#define ioremap_wt ioremap_nocache
+#endif
+
 #ifdef CONFIG_PCI
 /* Destroy a virtual mapping cookie for a PCI BAR (memory or IO) */
 struct pci_dev;

  parent reply	other threads:[~2015-02-25  0:15 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-25  0:14 [PATCH v8 0/7] Support Write-Through mapping on x86 Toshi Kani
2015-02-25  0:14 ` [PATCH v8 1/7] x86, mm, pat: Set WT to PA7 slot of PAT MSR Toshi Kani
2015-02-25  0:14 ` [PATCH v8 2/7] x86, mm, pat: Change reserve_memtype() to handle WT Toshi Kani
2015-02-25  0:14 ` Toshi Kani [this message]
2015-02-25  0:14 ` [PATCH v8 4/7] x86, mm, pat: Add pgprot_writethrough() for WT Toshi Kani
2015-02-25  0:14 ` [PATCH v8 5/7] x86, mm, pat: Refactor !pat_enabled handling Toshi Kani
2015-02-25  0:15 ` [PATCH v8 6/7] x86, mm, asm: Add WT support to set_page_memtype() Toshi Kani
2015-02-25  0:15 ` [PATCH v8 7/7] x86, mm: Add set_memory_wt() for WT Toshi Kani
2015-02-25  7:22   ` Ingo Molnar
2015-02-25 15:20     ` Toshi Kani
2015-02-26 11:30       ` Ingo Molnar
2015-02-26 14:44         ` Toshi Kani
2015-03-04 18:27           ` Toshi Kani

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