[PATCH] Remove duplicated code for reading control registers

[PATCH] Remove duplicated code for reading control registers

[Glauber de Oliveira Costa]

Tiny cleanup:

In x86_64, the same functions for reading cr3 and writing cr{3,4} are
defined in tlbflush.h and system.h, whith just a name change.
The only difference is the clobbering of memory, which seems a safe, and
even needed change for the write_cr4. This patch removes the duplicate.
write_cr3() is moved to system.h for consistency.

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>

-- 
Glauber de Oliveira Costa
Red Hat Inc.
"Free as in Freedom"

Re: [PATCH] Remove duplicated code for reading control registers

[Glauber de Oliveira Costa]

[-- Attachment #1: Type: text/plain, Size: 603 bytes --]

On Tue, Mar 13, 2007 at 05:33:09AM -0700, Randy.Dunlap wrote:
> On Tue, 13 Mar 2007, Glauber de Oliveira Costa wrote:
> 
> > Tiny cleanup:
> >
> > In x86_64, the same functions for reading cr3 and writing cr{3,4} are
> > defined in tlbflush.h and system.h, whith just a name change.
> > The only difference is the clobbering of memory, which seems a safe, and
> > even needed change for the write_cr4. This patch removes the duplicate.
> > write_cr3() is moved to system.h for consistency.
> 
> missing patch.....
> 
thanks. Attached now

-- 
Glauber de Oliveira Costa
Red Hat Inc.
"Free as in Freedom"

[-- Attachment #2: cleanup.patch --]
[-- Type: text/plain, Size: 2146 bytes --]

---

 include/asm-x86_64/system.h   |    7 ++++++-
 include/asm-x86_64/tlbflush.h |   33 +++++----------------------------
 2 files changed, 11 insertions(+), 29 deletions(-)

2d19cf472903fa4c9e763301b7b1cc0fa53bd023
diff --git a/include/asm-x86_64/system.h b/include/asm-x86_64/system.h
index bd376bc..91b461d 100644
--- a/include/asm-x86_64/system.h
+++ b/include/asm-x86_64/system.h
@@ -89,6 +89,11 @@ static inline unsigned long read_cr3(voi
 	return cr3;
 } 
 
+static inline void write_cr3(unsigned long val)
+{ 
+	asm volatile("movq %0,%%cr3" :: "r" (val) : "memory");
+} 
+
 static inline unsigned long read_cr4(void)
 { 
 	unsigned long cr4;
@@ -98,7 +103,7 @@ static inline unsigned long read_cr4(voi
 
 static inline void write_cr4(unsigned long val)
 { 
-	asm volatile("movq %0,%%cr4" :: "r" (val));
+	asm volatile("movq %0,%%cr4" :: "r" (val) : "memory");
 } 
 
 #define stts() write_cr0(8 | read_cr0())
diff --git a/include/asm-x86_64/tlbflush.h b/include/asm-x86_64/tlbflush.h
index 983bd29..512401b 100644
--- a/include/asm-x86_64/tlbflush.h
+++ b/include/asm-x86_64/tlbflush.h
@@ -3,41 +3,18 @@
 
 #include <linux/mm.h>
 #include <asm/processor.h>
-
-static inline unsigned long get_cr3(void)
-{
-	unsigned long cr3;
-	asm volatile("mov %%cr3,%0" : "=r" (cr3));
-	return cr3;
-}
-
-static inline void set_cr3(unsigned long cr3)
-{
-	asm volatile("mov %0,%%cr3" :: "r" (cr3) : "memory");
-}
+#include <asm/system.h>
 
 static inline void __flush_tlb(void)
 {
-	set_cr3(get_cr3());
-}
-
-static inline unsigned long get_cr4(void)
-{
-	unsigned long cr4;
-	asm volatile("mov %%cr4,%0" : "=r" (cr4));
-	return cr4;
-}
-
-static inline void set_cr4(unsigned long cr4)
-{
-	asm volatile("mov %0,%%cr4" :: "r" (cr4) : "memory");
+	write_cr3(read_cr3());
 }
 
 static inline void __flush_tlb_all(void)
 {
-	unsigned long cr4 = get_cr4();
-	set_cr4(cr4 & ~X86_CR4_PGE);	/* clear PGE */
-	set_cr4(cr4);			/* write old PGE again and flush TLBs */
+	unsigned long cr4 = read_cr4();
+	write_cr4(cr4 & ~X86_CR4_PGE);	/* clear PGE */
+	write_cr4(cr4);			/* write old PGE again and flush TLBs */
 }
 
 #define __flush_tlb_one(addr) \
-- 
1.1.3