ftrace: store mcount address in rec->ip
Record the address of the mcount call-site. Currently all archs except sparc64
record the address of the instruction following the mcount call-site. Some
general cleanups are entailed. Storing mcount addresses in rec->ip enables
looking them up in the kprobe hash table later on to check if they're kprobe'd.
Signed-off-by: Abhishek Sagar <sagar.abhishek@gmail.com>
Cc: davem@davemloft.net
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index e12c593..3855ceb 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -15,8 +15,8 @@
#include <linux/list.h>
#include <asm/cacheflush.h>
+#include <asm/ftrace.h>
-#define CALL_BACK 4
static unsigned int ftrace_nop = 0x60000000;
@@ -27,9 +27,10 @@
# define GET_ADDR(addr) *(unsigned long *)addr
#endif
+
static unsigned int notrace ftrace_calc_offset(long ip, long addr)
{
- return (int)((addr + CALL_BACK) - ip);
+ return (int)(addr - ip);
}
notrace unsigned char *ftrace_nop_replace(void)
@@ -76,9 +77,6 @@
unsigned new = *(unsigned *)new_code;
int faulted = 0;
- /* move the IP back to the start of the call */
- ip -= CALL_BACK;
-
/*
* Note: Due to modules and __init, code can
* disappear and change, we need to protect against faulting
@@ -118,12 +116,10 @@
notrace int ftrace_update_ftrace_func(ftrace_func_t func)
{
unsigned long ip = (unsigned long)(&ftrace_call);
- unsigned char old[4], *new;
+ unsigned char old[MCOUNT_INSN_SIZE], *new;
int ret;
- ip += CALL_BACK;
-
- memcpy(old, &ftrace_call, 4);
+ memcpy(old, &ftrace_call, MCOUNT_INSN_SIZE);
new = ftrace_call_replace(ip, (unsigned long)func);
ret = ftrace_modify_code(ip, old, new);
@@ -134,16 +130,13 @@
{
unsigned long ip = (long)(&mcount_call);
unsigned long *addr = data;
- unsigned char old[4], *new;
-
- /* ip is at the location, but modify code will subtact this */
- ip += CALL_BACK;
+ unsigned char old[MCOUNT_INSN_SIZE], *new;
/*
* Replace the mcount stub with a pointer to the
* ip recorder function.
*/
- memcpy(old, &mcount_call, 4);
+ memcpy(old, &mcount_call, MCOUNT_INSN_SIZE);
new = ftrace_call_replace(ip, *addr);
*addr = ftrace_modify_code(ip, old, new);