linux-kernel - [PATCH 2/5] x86, sleep: always save the value of EFER

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Date:	Fri, 13 Nov 2009 15:28:14 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	linux-kernel@...r.kernel.org
Cc:	mingo@...e.hu, tglx@...utronix.de, x86@...nel.org,
	"H. Peter Anvin" <hpa@...or.com>, Pavel Machek <pavel@....cz>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Nigel Cunningham <nigel@...onice.net>
Subject: [PATCH 2/5] x86, sleep: always save the value of EFER

Always save the value of EFER, regardless of the state of NX.  Since
EFER may not actually exist, use rdmsr_safe() to do so.

Signed-off-by: H. Peter Anvin <hpa@...or.com>
Cc: Pavel Machek <pavel@....cz>
Cc: Rafael J. Wysocki <rjw@...k.pl>
Cc: Nigel Cunningham <nigel@...onice.net>
---
 arch/x86/kernel/acpi/sleep.c |    9 +++------
 1 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index ca93638..c2e4455 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -78,12 +78,9 @@ int acpi_save_state_mem(void)
 #ifndef CONFIG_64BIT
 	store_gdt((struct desc_ptr *)&header->pmode_gdt);
 
-	header->pmode_efer_low = nx_enabled;
-	if (header->pmode_efer_low & 1) {
-		/* This is strange, why not save efer, always? */
-		rdmsr(MSR_EFER, header->pmode_efer_low,
-			header->pmode_efer_high);
-	}
+	header->pmode_efer_low = header->pmode_efer_high = 0;
+	rdmsr_safe(MSR_EFER,
+		   &header->pmode_efer_low, &header->pmode_efer_high);
 #endif /* !CONFIG_64BIT */
 
 	header->pmode_cr0 = read_cr0();
-- 
1.6.2.5

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