linux-kernel - [PATCH 4/9] remove references to cr8 register

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Message-Id: <1196867333728-git-send-email-gcosta@redhat.com>
Date:	Wed,  5 Dec 2007 13:08:28 -0200
From:	Glauber de Oliveira Costa <gcosta@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	akpm@...ux-foundation.org, glommer@...il.com, tglx@...utronix.de,
	mingo@...e.hu, ehabkost@...hat.com, jeremy@...p.org,
	avi@...ranet.com, anthony@...emonkey.ws,
	virtualization@...ts.linux-foundation.org, rusty@...tcorp.com.au,
	ak@...e.de, chrisw@...s-sol.org, rostedt@...dmis.org,
	hpa@...or.com, Glauber de Oliveira Costa <gcosta@...hat.com>
Subject: [PATCH 4/9] remove references to cr8 register

As pointed out by Andi, linux never really uses this register
so saving and restoring is not really necessary. This patch
removes all references to it.

Signed-off-by: Glauber de Oliveira Costa <gcosta@...hat.com>
---
 arch/x86/kernel/asm-offsets_64.c |    1 -
 arch/x86/kernel/suspend_64.c     |    2 --
 include/asm-x86/suspend_64.h     |    2 +-
 include/asm-x86/system_64.h      |   12 ------------
 4 files changed, 1 insertions(+), 16 deletions(-)

Index: linux-2.6-x86/arch/x86/kernel/asm-offsets_64.c
===================================================================
--- linux-2.6-x86.orig/arch/x86/kernel/asm-offsets_64.c
+++ linux-2.6-x86/arch/x86/kernel/asm-offsets_64.c
@@ -107,7 +107,6 @@ int main(void)
 	ENTRY(cr2);
 	ENTRY(cr3);
 	ENTRY(cr4);
-	ENTRY(cr8);
 	BLANK();
 #undef ENTRY
 	DEFINE(TSS_ist, offsetof(struct tss_struct, ist));
Index: linux-2.6-x86/arch/x86/kernel/suspend_64.c
===================================================================
--- linux-2.6-x86.orig/arch/x86/kernel/suspend_64.c
+++ linux-2.6-x86/arch/x86/kernel/suspend_64.c
@@ -53,7 +53,6 @@ void __save_processor_state(struct saved
 	ctxt->cr2 = read_cr2();
 	ctxt->cr3 = read_cr3();
 	ctxt->cr4 = read_cr4();
-	ctxt->cr8 = read_cr8();
 }
 
 void save_processor_state(void)
@@ -75,7 +74,6 @@ void __restore_processor_state(struct sa
 	 * control registers
 	 */
 	wrmsrl(MSR_EFER, ctxt->efer);
-	write_cr8(ctxt->cr8);
 	write_cr4(ctxt->cr4);
 	write_cr3(ctxt->cr3);
 	write_cr2(ctxt->cr2);
Index: linux-2.6-x86/include/asm-x86/suspend_64.h
===================================================================
--- linux-2.6-x86.orig/include/asm-x86/suspend_64.h
+++ linux-2.6-x86/include/asm-x86/suspend_64.h
@@ -20,7 +20,7 @@ struct saved_context {
 	struct pt_regs regs;
   	u16 ds, es, fs, gs, ss;
 	unsigned long gs_base, gs_kernel_base, fs_base;
-	unsigned long cr0, cr2, cr3, cr4, cr8;
+	unsigned long cr0, cr2, cr3, cr4;
 	unsigned long efer;
 	u16 gdt_pad;
 	u16 gdt_limit;
Index: linux-2.6-x86/include/asm-x86/system_64.h
===================================================================
--- linux-2.6-x86.orig/include/asm-x86/system_64.h
+++ linux-2.6-x86/include/asm-x86/system_64.h
@@ -95,18 +95,6 @@ static inline void write_cr4(unsigned lo
 	asm volatile("movq %0,%%cr4" :: "r" (val) : "memory");
 }
 
-static inline unsigned long read_cr8(void)
-{
-	unsigned long cr8;
-	asm volatile("movq %%cr8,%0" : "=r" (cr8));
-	return cr8;
-}
-
-static inline void write_cr8(unsigned long val)
-{
-	asm volatile("movq %0,%%cr8" :: "r" (val) : "memory");
-}
-
 #define stts() write_cr0(8 | read_cr0())
 
 #define wbinvd() \
--
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