3 files changed, 51 insertions, 45 deletions

diff --git a/arch/i386/kernel/crash.c b/arch/i386/kernel/crash.c
index f1e65c2ead6e..d49dbe8dc96b 100644
--- a/arch/i386/kernel/crash.c
+++ b/arch/i386/kernel/crash.c
@@ -82,53 +82,12 @@ static void crash_save_this_cpu(struct pt_regs *regs, int cpu)
         final_note(buf);
 }
 
-static void crash_get_current_regs(struct pt_regs *regs)
+static void crash_save_self(struct pt_regs *regs)
 {
-        __asm__ __volatile__("movl %%ebx,%0" : "=m"(regs->ebx));
-        __asm__ __volatile__("movl %%ecx,%0" : "=m"(regs->ecx));
-        __asm__ __volatile__("movl %%edx,%0" : "=m"(regs->edx));
-        __asm__ __volatile__("movl %%esi,%0" : "=m"(regs->esi));
-        __asm__ __volatile__("movl %%edi,%0" : "=m"(regs->edi));
-        __asm__ __volatile__("movl %%ebp,%0" : "=m"(regs->ebp));
-        __asm__ __volatile__("movl %%eax,%0" : "=m"(regs->eax));
-        __asm__ __volatile__("movl %%esp,%0" : "=m"(regs->esp));
-        __asm__ __volatile__("movw %%ss, %%ax;" :"=a"(regs->xss));
-        __asm__ __volatile__("movw %%cs, %%ax;" :"=a"(regs->xcs));
-        __asm__ __volatile__("movw %%ds, %%ax;" :"=a"(regs->xds));
-        __asm__ __volatile__("movw %%es, %%ax;" :"=a"(regs->xes));
-        __asm__ __volatile__("pushfl; popl %0" :"=m"(regs->eflags));
-
-        regs->eip = (unsigned long)current_text_addr();
-}
-
-/* CPU does not save ss and esp on stack if execution is already
- * running in kernel mode at the time of NMI occurrence. This code
- * fixes it.
- */
-static void crash_setup_regs(struct pt_regs *newregs, struct pt_regs *oldregs)
-{
-        memcpy(newregs, oldregs, sizeof(*newregs));
-        newregs->esp = (unsigned long)&(oldregs->esp);
-        __asm__ __volatile__(
-                        "xorl %%eax, %%eax\n\t"
-                        "movw %%ss, %%ax\n\t"
-                        :"=a"(newregs->xss));
-}
-
-/* We may have saved_regs from where the error came from
- * or it is NULL if via a direct panic().
- */
-static void crash_save_self(struct pt_regs *saved_regs)
-{
-        struct pt_regs regs;
         int cpu;
 
         cpu = smp_processor_id();
-        if (saved_regs)
-                crash_setup_regs(&regs, saved_regs);
-        else
-                crash_get_current_regs(&regs);
-        crash_save_this_cpu(&regs, cpu);
+        crash_save_this_cpu(regs, cpu);
 }
 
 #ifdef CONFIG_SMP
@@ -147,7 +106,7 @@ static int crash_nmi_callback(struct pt_regs *regs, int cpu)
         local_irq_disable();
 
         if (!user_mode(regs)) {
-                crash_setup_regs(&fixed_regs, regs);
+                crash_fixup_ss_esp(&fixed_regs, regs);
                 regs = &fixed_regs;
         }
         crash_save_this_cpu(regs, cpu);
diff --git a/include/asm-i386/kexec.h b/include/asm-i386/kexec.h
index d80d446498fb..8fb1defd98c6 100644
--- a/include/asm-i386/kexec.h
+++ b/include/asm-i386/kexec.h
@@ -2,6 +2,7 @@
 #define _I386_KEXEC_H
 
 #include <asm/fixmap.h>
+#include <asm/ptrace.h>
 
 /*
  * KEXEC_SOURCE_MEMORY_LIMIT maximum page get_free_page can return.
@@ -27,4 +28,48 @@
 
 #define MAX_NOTE_BYTES 1024
 
+/* CPU does not save ss and esp on stack if execution is already
+ * running in kernel mode at the time of NMI occurrence. This code
+ * fixes it.
+ */
+static inline void crash_fixup_ss_esp(struct pt_regs *newregs,
+                                        struct pt_regs *oldregs)
+{
+        memcpy(newregs, oldregs, sizeof(*newregs));
+        newregs->esp = (unsigned long)&(oldregs->esp);
+        __asm__ __volatile__(
+                        "xorl %%eax, %%eax\n\t"
+                        "movw %%ss, %%ax\n\t"
+                        :"=a"(newregs->xss));
+}
+
+/*
+ * This function is responsible for capturing register states if coming
+ * via panic otherwise just fix up the ss and esp if coming via kernel
+ * mode exception.
+ */
+static inline void crash_setup_regs(struct pt_regs *newregs,
+                                       struct pt_regs *oldregs)
+{
+       if (oldregs)
+               crash_fixup_ss_esp(newregs, oldregs);
+       else {
+               __asm__ __volatile__("movl %%ebx,%0" : "=m"(newregs->ebx));
+               __asm__ __volatile__("movl %%ecx,%0" : "=m"(newregs->ecx));
+               __asm__ __volatile__("movl %%edx,%0" : "=m"(newregs->edx));
+               __asm__ __volatile__("movl %%esi,%0" : "=m"(newregs->esi));
+               __asm__ __volatile__("movl %%edi,%0" : "=m"(newregs->edi));
+               __asm__ __volatile__("movl %%ebp,%0" : "=m"(newregs->ebp));
+               __asm__ __volatile__("movl %%eax,%0" : "=m"(newregs->eax));
+               __asm__ __volatile__("movl %%esp,%0" : "=m"(newregs->esp));
+               __asm__ __volatile__("movw %%ss, %%ax;" :"=a"(newregs->xss));
+               __asm__ __volatile__("movw %%cs, %%ax;" :"=a"(newregs->xcs));
+               __asm__ __volatile__("movw %%ds, %%ax;" :"=a"(newregs->xds));
+               __asm__ __volatile__("movw %%es, %%ax;" :"=a"(newregs->xes));
+               __asm__ __volatile__("pushfl; popl %0" :"=m"(newregs->eflags));
+
+               newregs->eip = (unsigned long)current_text_addr();
+       }
+}
+
 #endif /* _I386_KEXEC_H */
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 1197de8b2a94..de1441656efd 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -1057,7 +1057,9 @@ void crash_kexec(struct pt_regs *regs)
         if (!locked) {
                 image = xchg(&kexec_crash_image, NULL);
                 if (image) {
-                        machine_crash_shutdown(regs);
+                        struct pt_regs fixed_regs;
+                        crash_setup_regs(&fixed_regs, regs);
+                        machine_crash_shutdown(&fixed_regs);
                         machine_kexec(image);
                 }
                 xchg(&kexec_lock, 0);