hw-breakpoints: cleanup HW Breakpoint registers before kexec

This patch disables Hardware breakpoints before doing a 'kexec' on the machine
so that the cpu doesn't keep debug registers values which would be out of
sync for the new image.

Original-patch-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

2 files changed, 4 insertions, 0 deletions

diff --git a/arch/x86/kernel/machine_kexec_32.c b/arch/x86/kernel/machine_kexec_32.c
index c1c429d00130..c843f8406da2 100644
--- a/arch/x86/kernel/machine_kexec_32.c
+++ b/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();
+        hw_breakpoint_disable();
 
         if (image->preserve_context) {
 #ifdef CONFIG_X86_IO_APIC
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 84c3bf209e98..4a8bb82248ae 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -18,6 +18,7 @@
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 #include <asm/mmu_context.h>
+#include <asm/debugreg.h>
 
 static int init_one_level2_page(struct kimage *image, pgd_t *pgd,
                                 unsigned long addr)
@@ -282,6 +283,7 @@ void machine_kexec(struct kimage *image)
 
         /* Interrupts aren't acceptable while we reboot */
         local_irq_disable();
+        hw_breakpoint_disable();
 
         if (image->preserve_context) {
 #ifdef CONFIG_X86_IO_APIC