1 #include <linux/spinlock.h>
2 #include <linux/hardirq.h>
3 #include <linux/ftrace.h>
4 #include <linux/percpu.h>
5 #include <linux/init.h>
6 #include <linux/list.h>
8 static const u32 ftrace_nop = 0x01000000;
10 notrace unsigned char *ftrace_nop_replace(void)
12 return (char *)&ftrace_nop;
15 notrace unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
20 off = ((s32)addr - (s32)ip);
21 call = 0x40000000 | ((u32)off >> 2);
23 return (unsigned char *) &call;
27 ftrace_modify_code(unsigned long ip, unsigned char *old_code,
28 unsigned char *new_code)
30 u32 old = *(u32 *)old_code;
31 u32 new = *(u32 *)new_code;
36 "1: cas [%[ip]], %[old], %[new]\n"
38 " mov 0, %[faulted]\n"
40 " .section .fixup,#alloc,#execinstr\n"
42 "3: sethi %%hi(2b), %[faulted]\n"
43 " jmpl %[faulted] + %%lo(2b), %%g0\n"
44 " mov 1, %[faulted]\n"
46 " .section __ex_table,\"a\"\n"
50 : "=r" (replaced), [faulted] "=r" (faulted)
51 : [new] "0" (new), [old] "r" (old), [ip] "r" (ip)
54 if (replaced != old && replaced != new)
60 notrace int ftrace_update_ftrace_func(ftrace_func_t func)
62 unsigned long ip = (unsigned long)(&ftrace_call);
63 unsigned char old[4], *new;
65 memcpy(old, &ftrace_call, 4);
66 new = ftrace_call_replace(ip, (unsigned long)func);
67 return ftrace_modify_code(ip, old, new);
70 notrace int ftrace_mcount_set(unsigned long *data)
72 unsigned long ip = (long)(&mcount_call);
73 unsigned long *addr = data;
74 unsigned char old[4], *new;
77 * Replace the mcount stub with a pointer to the
78 * ip recorder function.
80 memcpy(old, &mcount_call, 4);
81 new = ftrace_call_replace(ip, *addr);
82 *addr = ftrace_modify_code(ip, old, new);
88 int __init ftrace_dyn_arch_init(void *data)
90 ftrace_mcount_set(data);