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/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
index 22f3d6e..76d50e6 100644
--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -12,9 +12,10 @@
*/
#include <linux/ftrace.h>
-#include <asm/cacheflush.h>
-#define INSN_SIZE 4
+#include <asm/cacheflush.h>
+#include <asm/ftrace.h>
+
#define PC_OFFSET 8
#define BL_OPCODE 0xeb000000
#define BL_OFFSET_MASK 0x00ffffff
@@ -32,10 +33,10 @@
{
long offset;
- offset = (long)addr - (long)(pc - INSN_SIZE + PC_OFFSET);
+ offset = (long)addr - (long)(pc + PC_OFFSET);
if (unlikely(offset < -33554432 || offset > 33554428)) {
/* Can't generate branches that far (from ARM ARM). Ftrace
- * doesn't generate branches outside of core kernel text.
+ * doesn't generate branches outside of kernel text.
*/
WARN_ON_ONCE(1);
return NULL;
@@ -52,7 +53,6 @@
old = *(unsigned long *)old_code;
new = *(unsigned long *)new_code;
- pc -= INSN_SIZE;
__asm__ __volatile__ (
"1: ldr %1, [%2] \n"
@@ -77,7 +77,7 @@
: "memory");
if (!err && (replaced == old))
- flush_icache_range(pc, pc + INSN_SIZE);
+ flush_icache_range(pc, pc + MCOUNT_INSN_SIZE);
return err;
}
@@ -89,8 +89,7 @@
unsigned char *new;
pc = (unsigned long)&ftrace_call;
- pc += INSN_SIZE;
- memcpy(&old, &ftrace_call, INSN_SIZE);
+ memcpy(&old, &ftrace_call, MCOUNT_INSN_SIZE);
new = ftrace_call_replace(pc, (unsigned long)func);
ret = ftrace_modify_code(pc, (unsigned char *)&old, new);
return ret;
@@ -103,8 +102,7 @@
unsigned char *new;
pc = (unsigned long)&mcount_call;
- pc += INSN_SIZE;
- memcpy(&old, &mcount_call, INSN_SIZE);
+ memcpy(&old, &mcount_call, MCOUNT_INSN_SIZE);
new = ftrace_call_replace(pc, *addr);
*addr = ftrace_modify_code(pc, (unsigned char *)&old, new);
return 0;