linux-kernel - [PATCH 1/4] x86/wakeup/sleep: Check whether the TSS GDT descriptor is empty before using it.

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Message-Id: <1350481786-4969-2-git-send-email-konrad.wilk@oracle.com>
Date:	Wed, 17 Oct 2012 09:49:43 -0400
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	linux-kernel@...r.kernel.org, xen-devel@...ts.xensource.com,
	lenb@...nel.org, linux-acpi@...r.kernel.org, hpa@...or.com,
	x86@...nel.org
Cc:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Subject: [PATCH 1/4] x86/wakeup/sleep: Check whether the TSS GDT descriptor is empty before using it.

We check the TSS descriptor before we try to dereference it.
Also fix up the value to use the #defines.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
---
 arch/x86/power/cpu.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index 218cdb1..c17370e 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -133,7 +133,9 @@ static void fix_processor_context(void)
 {
 	int cpu = smp_processor_id();
 	struct tss_struct *t = &per_cpu(init_tss, cpu);
-
+#ifdef CONFIG_X86_64
+	struct desc_struct *desc = get_cpu_gdt_table(cpu);
+#endif
 	set_tss_desc(cpu, t);	/*
 				 * This just modifies memory; should not be
 				 * necessary. But... This is necessary, because
@@ -142,7 +144,8 @@ static void fix_processor_context(void)
 				 */
 
 #ifdef CONFIG_X86_64
-	get_cpu_gdt_table(cpu)[GDT_ENTRY_TSS].type = 9;
+	if (!desc_empty(&desc[GDT_ENTRY_TSS]))
+		desc[GDT_ENTRY_TSS].type = DESC_TSS;
 
 	syscall_init();				/* This sets MSR_*STAR and related */
 #endif
-- 
1.7.7.6

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