1 files changed, 24 insertions, 3 deletions

diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c
index 782bd0a3c2f0..c470a40b29f5 100644
--- a/arch/powerpc/kernel/kgdb.c
+++ b/arch/powerpc/kernel/kgdb.c
@@ -25,6 +25,7 @@
 #include <asm/processor.h>
 #include <asm/machdep.h>
 #include <asm/debug.h>
+#include <linux/slab.h>
 
 /*
  * This table contains the mapping between PowerPC hardware trap types, and
@@ -101,6 +102,21 @@ static int computeSignal(unsigned int tt)
         return SIGHUP;          /* default for things we don't know about */
 }
 
+/**
+ *
+ *      kgdb_skipexception - Bail out of KGDB when we've been triggered.
+ *      @exception: Exception vector number
+ *      @regs: Current &struct pt_regs.
+ *
+ *      On some architectures we need to skip a breakpoint exception when
+ *      it occurs after a breakpoint has been removed.
+ *
+ */
+int kgdb_skipexception(int exception, struct pt_regs *regs)
+{
+        return kgdb_isremovedbreak(regs->nip);
+}
+
 static int kgdb_call_nmi_hook(struct pt_regs *regs)
 {
         kgdb_nmicallback(raw_smp_processor_id(), regs);
@@ -138,6 +154,8 @@ static int kgdb_handle_breakpoint(struct pt_regs *regs)
 static int kgdb_singlestep(struct pt_regs *regs)
 {
         struct thread_info *thread_info, *exception_thread_info;
+        struct thread_info *backup_current_thread_info = \
+                (struct thread_info *)kmalloc(sizeof(struct thread_info), GFP_KERNEL);
 
         if (user_mode(regs))
                 return 0;
@@ -155,13 +173,17 @@ static int kgdb_singlestep(struct pt_regs *regs)
         thread_info = (struct thread_info *)(regs->gpr[1] & ~(THREAD_SIZE-1));
         exception_thread_info = current_thread_info();
 
-        if (thread_info != exception_thread_info)
+        if (thread_info != exception_thread_info) {
+                /* Save the original current_thread_info. */
+                memcpy(backup_current_thread_info, exception_thread_info, sizeof *thread_info);
                 memcpy(exception_thread_info, thread_info, sizeof *thread_info);
+        }
 
         kgdb_handle_exception(0, SIGTRAP, 0, regs);
 
         if (thread_info != exception_thread_info)
-                memcpy(thread_info, exception_thread_info, sizeof *thread_info);
+                /* Restore current_thread_info lastly. */
+                memcpy(exception_thread_info, backup_current_thread_info, sizeof *thread_info);
 
         return 1;
 }
@@ -410,7 +432,6 @@ int kgdb_arch_handle_exception(int vector, int signo, int err_code,
 #else
                         linux_regs->msr |= MSR_SE;
 #endif
-                        kgdb_single_step = 1;
                         atomic_set(&kgdb_cpu_doing_single_step,
                                    raw_smp_processor_id());
                 }