3 files changed, 2 insertions, 52 deletions

diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index b21fbfaffe39..4e4269c73bb7 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1153,20 +1153,6 @@ ENDPROC(xen_failsafe_callback)
 #ifdef CONFIG_DYNAMIC_FTRACE
 
 ENTRY(mcount)
-        pushl %eax
-        pushl %ecx
-        pushl %edx
-        movl 0xc(%esp), %eax
-        subl $MCOUNT_INSN_SIZE, %eax
-
-.globl mcount_call
-mcount_call:
-        call ftrace_stub
-
-        popl %edx
-        popl %ecx
-        popl %eax
-
         ret
 END(mcount)
 
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 1db6ce4314e1..09e7145484c5 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -64,32 +64,6 @@
 #ifdef CONFIG_FTRACE
 #ifdef CONFIG_DYNAMIC_FTRACE
 ENTRY(mcount)
-
-        subq $0x38, %rsp
-        movq %rax, (%rsp)
-        movq %rcx, 8(%rsp)
-        movq %rdx, 16(%rsp)
-        movq %rsi, 24(%rsp)
-        movq %rdi, 32(%rsp)
-        movq %r8, 40(%rsp)
-        movq %r9, 48(%rsp)
-
-        movq 0x38(%rsp), %rdi
-        subq $MCOUNT_INSN_SIZE, %rdi
-
-.globl mcount_call
-mcount_call:
-        call ftrace_stub
-
-        movq 48(%rsp), %r9
-        movq 40(%rsp), %r8
-        movq 32(%rsp), %rdi
-        movq 24(%rsp), %rsi
-        movq 16(%rsp), %rdx
-        movq 8(%rsp), %rcx
-        movq (%rsp), %rax
-        addq $0x38, %rsp
-
         retq
 END(mcount)
 
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index ab115cd15fdf..96aadbfedcc6 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -112,18 +112,8 @@ notrace int ftrace_update_ftrace_func(ftrace_func_t func)
 
 notrace int ftrace_mcount_set(unsigned long *data)
 {
-        unsigned long ip = (long)(&mcount_call);
-        unsigned long *addr = data;
-        unsigned char old[MCOUNT_INSN_SIZE], *new;
-
-        /*
-         * Replace the mcount stub with a pointer to the
-         * ip recorder function.
-         */
-        memcpy(old, &mcount_call, MCOUNT_INSN_SIZE);
-        new = ftrace_call_replace(ip, *addr);
-        *addr = ftrace_modify_code(ip, old, new);
-
+        /* mcount is initialized as a nop */
+        *data = 0;
         return 0;
 }