ftrace: Remove FTRACE_UPDATE_MODIFY_CALL_REGS flag

As the decision to what needs to be done (converting a call to the
ftrace_caller to ftrace_caller_regs or to convert from ftrace_caller_regs
to ftrace_caller) can easily be determined from the rec->flags of
FTRACE_FL_REGS and FTRACE_FL_REGS_EN, there's no need to have the
ftrace_check_record() return either a UPDATE_MODIFY_CALL_REGS or a
UPDATE_MODIFY_CALL. Just he latter is enough. This added flag causes
more complexity than is required. Remove it.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

3 files changed, 4 insertions, 14 deletions

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 5ef43ce8492f..89de3eaf8772 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -366,7 +366,6 @@ static int add_breakpoints(struct dyn_ftrace *rec, int enable)
                 /* converting nop to call */
                 return add_brk_on_nop(rec);
 
-        case FTRACE_UPDATE_MODIFY_CALL_REGS:
         case FTRACE_UPDATE_MODIFY_CALL:
         case FTRACE_UPDATE_MAKE_NOP:
                 /* converting a call to a nop */
@@ -469,7 +468,6 @@ static int add_update(struct dyn_ftrace *rec, int enable)
         case FTRACE_UPDATE_IGNORE:
                 return 0;
 
-        case FTRACE_UPDATE_MODIFY_CALL_REGS:
         case FTRACE_UPDATE_MODIFY_CALL:
         case FTRACE_UPDATE_MAKE_CALL:
                 /* converting nop to call */
@@ -516,7 +514,6 @@ static int finish_update(struct dyn_ftrace *rec, int enable)
         case FTRACE_UPDATE_IGNORE:
                 return 0;
 
-        case FTRACE_UPDATE_MODIFY_CALL_REGS:
         case FTRACE_UPDATE_MODIFY_CALL:
         case FTRACE_UPDATE_MAKE_CALL:
                 /* converting nop to call */
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 2f8cbffecd3d..3e6dfb31f8e6 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -362,14 +362,12 @@ enum {
  *  IGNORE           - The function is already what we want it to be
  *  MAKE_CALL        - Start tracing the function
  *  MODIFY_CALL      - Stop saving regs for the function
- *  MODIFY_CALL_REGS - Start saving regs for the function
  *  MAKE_NOP         - Stop tracing the function
  */
 enum {
         FTRACE_UPDATE_IGNORE,
         FTRACE_UPDATE_MAKE_CALL,
         FTRACE_UPDATE_MODIFY_CALL,
-        FTRACE_UPDATE_MODIFY_CALL_REGS,
         FTRACE_UPDATE_MAKE_NOP,
 };
 
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 52c2b53b7953..cc07b7fc4372 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1701,19 +1701,15 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
                 /*
                  * If this record is being updated from a nop, then
                  *   return UPDATE_MAKE_CALL.
-                 * Otherwise, if the EN flag is set, then return
-                 *   UPDATE_MODIFY_CALL_REGS to tell the caller to convert
-                 *   from the non-save regs, to a save regs function.
                  * Otherwise,
                  *   return UPDATE_MODIFY_CALL to tell the caller to convert
-                 *   from the save regs, to a non-save regs function.
+                 *   from the save regs, to a non-save regs function or
+                 *   vice versa.
                  */
                 if (flag & FTRACE_FL_ENABLED)
                         return FTRACE_UPDATE_MAKE_CALL;
-                else if (rec->flags & FTRACE_FL_REGS_EN)
-                        return FTRACE_UPDATE_MODIFY_CALL_REGS;
-                else
-                        return FTRACE_UPDATE_MODIFY_CALL;
+
+                return FTRACE_UPDATE_MODIFY_CALL;
         }
 
         if (update) {
@@ -1815,7 +1811,6 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
         case FTRACE_UPDATE_MAKE_NOP:
                 return ftrace_make_nop(NULL, rec, ftrace_addr);
 
-        case FTRACE_UPDATE_MODIFY_CALL_REGS:
         case FTRACE_UPDATE_MODIFY_CALL:
                 return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
         }