ftrace, ia64: IA64 static ftrace support

IA64 ftrace suppport. In IA64, below code will be added in each function
if -pg is enabled.

alloc r40=ar.pfs,12,8,0
mov r43=r0;;
mov r42=b0
mov r41=r1
nop.i 0x0
br.call.sptk.many b0 = _mcount;;

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 55 insertions, 0 deletions

diff --git a/arch/ia64/kernel/entry.S b/arch/ia64/kernel/entry.S
index d435f4a7a96c..c2f7d798e2a5 100644
--- a/arch/ia64/kernel/entry.S
+++ b/arch/ia64/kernel/entry.S
@@ -47,6 +47,7 @@
 #include <asm/processor.h>
 #include <asm/thread_info.h>
 #include <asm/unistd.h>
+#include <asm/ftrace.h>
 
 #include "minstate.h"
 
@@ -1404,6 +1405,54 @@ GLOBAL_ENTRY(unw_init_running)
         br.ret.sptk.many rp
 END(unw_init_running)
 
+#ifdef CONFIG_FUNCTION_TRACER
+GLOBAL_ENTRY(_mcount)
+        movl r2 = ftrace_stub
+        movl r3 = ftrace_trace_function;;
+        ld8 r3 = [r3];;
+        ld8 r3 = [r3];;
+        cmp.eq p7,p0 = r2, r3
+(p7)    br.sptk.many ftrace_stub
+        ;;
+
+        alloc loc0 = ar.pfs, 4, 4, 2, 0
+        ;;
+        mov loc1 = b0
+        mov out0 = b0
+        mov loc2 = r8
+        mov loc3 = r15
+        ;;
+        adds out0 = -MCOUNT_INSN_SIZE, out0
+        mov out1 = in2
+        mov b6 = r3
+
+        br.call.sptk.many b0 = b6
+        ;;
+        mov ar.pfs = loc0
+        mov b0 = loc1
+        mov r8 = loc2
+        mov r15 = loc3
+        br ftrace_stub
+        ;;
+END(_mcount)
+
+GLOBAL_ENTRY(ftrace_stub)
+        mov r3 = b0
+        movl r2 = _mcount_ret_helper
+        ;;
+        mov b6 = r2
+        mov b7 = r3
+        br.ret.sptk.many b6
+
+_mcount_ret_helper:
+        mov b0 = r42
+        mov r1 = r41
+        mov ar.pfs = r40
+        br b7
+END(ftrace_stub)
+
+#endif /* CONFIG_FUNCTION_TRACER */
+
         .rodata
         .align 8
         .globl sys_call_table
diff --git a/arch/ia64/kernel/ia64_ksyms.c b/arch/ia64/kernel/ia64_ksyms.c
index 6da1f20d7372..2d311864e359 100644
--- a/arch/ia64/kernel/ia64_ksyms.c
+++ b/arch/ia64/kernel/ia64_ksyms.c
@@ -112,3 +112,9 @@ EXPORT_SYMBOL_GPL(esi_call_phys);
 #endif
 extern char ia64_ivt[];
 EXPORT_SYMBOL(ia64_ivt);
+
+#include <asm/ftrace.h>
+#ifdef CONFIG_FUNCTION_TRACER
+/* mcount is defined in assembly */
+EXPORT_SYMBOL(_mcount);
+#endif