linux-kernel - [Patch 9/10] Cleanup HW Breakpoint registers before kexec

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Message-ID: <20090129083123.GF7750@in.ibm.com>
Date:	Thu, 29 Jan 2009 14:01:23 +0530
From:	"K.Prasad" <prasad@...ux.vnet.ibm.com>
To:	akpm@...ux-foundation.org,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Cc:	Alan Stern <stern@...land.harvard.edu>,
	Roland McGrath <roland@...hat.com>, mingo@...e.hu,
	richardj_moore@...ibm.com, jason.wessel@...driver.com
Subject: [Patch 9/10] Cleanup HW Breakpoint registers before kexec

This patch disables Hardware breakpoints before doing a 'kexec' on the machine.

Signed-off-by: K.Prasad <prasad@...ux.vnet.ibm.com>
Signed-off-by: Alan Stern <stern@...land.harvard.edu>
---
 arch/x86/kernel/machine_kexec_32.c |    2 ++
 arch/x86/kernel/machine_kexec_64.c |    2 ++
 2 files changed, 4 insertions(+)

Index: linux-hbkpt-lkml-29-rc2/arch/x86/kernel/machine_kexec_32.c
===================================================================
--- linux-hbkpt-lkml-29-rc2.orig/arch/x86/kernel/machine_kexec_32.c
+++ linux-hbkpt-lkml-29-rc2/arch/x86/kernel/machine_kexec_32.c
@@ -25,6 +25,7 @@
 #include <asm/desc.h>
 #include <asm/system.h>
 #include <asm/cacheflush.h>
+#include <asm/debugreg.h>
 
 static void set_idt(void *newidt, __u16 limit)
 {
@@ -202,6 +203,7 @@ void machine_kexec(struct kimage *image)
 
 	/* Interrupts aren't acceptable while we reboot */
 	local_irq_disable();
+	disable_debug_registers();
 
 	if (image->preserve_context) {
 #ifdef CONFIG_X86_IO_APIC
Index: linux-hbkpt-lkml-29-rc2/arch/x86/kernel/machine_kexec_64.c
===================================================================
--- linux-hbkpt-lkml-29-rc2.orig/arch/x86/kernel/machine_kexec_64.c
+++ linux-hbkpt-lkml-29-rc2/arch/x86/kernel/machine_kexec_64.c
@@ -17,6 +17,7 @@
 #include <asm/tlbflush.h>
 #include <asm/mmu_context.h>
 #include <asm/io.h>
+#include <asm/debugreg.h>
 
 #define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE)))
 static u64 kexec_pgd[512] PAGE_ALIGNED;
@@ -190,6 +191,7 @@ void machine_kexec(struct kimage *image)
 
 	/* Interrupts aren't acceptable while we reboot */
 	local_irq_disable();
+	disable_debug_registers();
 
 	control_page = page_address(image->control_code_page) + PAGE_SIZE;
 	memcpy(control_page, relocate_kernel, PAGE_SIZE);
--
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