linux-kernel - [PATCH 7/20] x86_64: Add EFER to the register set saved by save_processor

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Message-ID: <20070307070816.GH23412@in.ibm.com>
Date:	Wed, 7 Mar 2007 12:38:16 +0530
From:	Vivek Goyal <vgoyal@...ibm.com>
To:	linux kernel mailing list <linux-kernel@...r.kernel.org>
Cc:	Reloc Kernel List <fastboot@...ts.osdl.org>, ebiederm@...ssion.com,
	akpm@...ux-foundation.org, ak@...e.de, hpa@...or.com,
	magnus.damm@...il.com, lwang@...hat.com, dzickus@...hat.com,
	pavel@...e.cz, rjw@...k.pl
Subject: [PATCH 7/20] x86_64: Add EFER to the register set saved by save_processor_state



EFER varies like %cr4 depending on the cpu capabilities, and which cpu
capabilities we want to make use of.  So save/restore it make certain
we have the same EFER value when we are done.

Signed-off-by: Eric W. Biederman <ebiederm@...ssion.com>
Signed-off-by: Vivek Goyal <vgoyal@...ibm.com>
---

 arch/x86_64/kernel/suspend.c |    3 ++-
 include/asm-x86_64/suspend.h |    1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff -puN arch/x86_64/kernel/suspend.c~x86_64-Add-EFER-to-the-set-registers-saved-by-save_processor_state arch/x86_64/kernel/suspend.c
--- linux-2.6.19-rc6-reloc/arch/x86_64/kernel/suspend.c~x86_64-Add-EFER-to-the-set-registers-saved-by-save_processor_state	2006-11-17 00:08:16.000000000 -0500
+++ linux-2.6.19-rc6-reloc-root/arch/x86_64/kernel/suspend.c	2006-11-17 00:08:16.000000000 -0500
@@ -33,7 +33,6 @@ void __save_processor_state(struct saved
 	asm volatile ("str %0"  : "=m" (ctxt->tr));
 
 	/* XMM0..XMM15 should be handled by kernel_fpu_begin(). */
-	/* EFER should be constant for kernel version, no need to handle it. */
 	/*
 	 * segment registers
 	 */
@@ -50,6 +49,7 @@ void __save_processor_state(struct saved
 	/*
 	 * control registers 
 	 */
+	rdmsrl(MSR_EFER, ctxt->efer);
 	asm volatile ("movq %%cr0, %0" : "=r" (ctxt->cr0));
 	asm volatile ("movq %%cr2, %0" : "=r" (ctxt->cr2));
 	asm volatile ("movq %%cr3, %0" : "=r" (ctxt->cr3));
@@ -75,6 +75,7 @@ void __restore_processor_state(struct sa
 	/*
 	 * control registers
 	 */
+	wrmsrl(MSR_EFER, ctxt->efer);
 	asm volatile ("movq %0, %%cr8" :: "r" (ctxt->cr8));
 	asm volatile ("movq %0, %%cr4" :: "r" (ctxt->cr4));
 	asm volatile ("movq %0, %%cr3" :: "r" (ctxt->cr3));
diff -puN include/asm-x86_64/suspend.h~x86_64-Add-EFER-to-the-set-registers-saved-by-save_processor_state include/asm-x86_64/suspend.h
--- linux-2.6.19-rc6-reloc/include/asm-x86_64/suspend.h~x86_64-Add-EFER-to-the-set-registers-saved-by-save_processor_state	2006-11-17 00:08:16.000000000 -0500
+++ linux-2.6.19-rc6-reloc-root/include/asm-x86_64/suspend.h	2006-11-17 00:08:16.000000000 -0500
@@ -17,6 +17,7 @@ struct saved_context {
   	u16 ds, es, fs, gs, ss;
 	unsigned long gs_base, gs_kernel_base, fs_base;
 	unsigned long cr0, cr2, cr3, cr4, cr8;
+	unsigned long efer;
 	u16 gdt_pad;
 	u16 gdt_limit;
 	unsigned long gdt_base;
_
-
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