blob: d3b1a3076569890724fdc58a77fd1949ca96a684 [file] [log] [blame]
David Millerd05f5f92008-05-13 22:06:59 -07001#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>
7
Abhishek Sagar395a59d2008-06-21 23:47:27 +05308#include <asm/ftrace.h>
9
David S. Miller9be12f92009-06-13 01:03:24 -070010#ifdef CONFIG_DYNAMIC_FTRACE
David Millerd05f5f92008-05-13 22:06:59 -070011static const u32 ftrace_nop = 0x01000000;
12
David S. Miller9be12f92009-06-13 01:03:24 -070013static u32 ftrace_call_replace(unsigned long ip, unsigned long addr)
David Millerd05f5f92008-05-13 22:06:59 -070014{
15 static u32 call;
16 s32 off;
17
18 off = ((s32)addr - (s32)ip);
19 call = 0x40000000 | ((u32)off >> 2);
20
David S. Miller9be12f92009-06-13 01:03:24 -070021 return call;
David Millerd05f5f92008-05-13 22:06:59 -070022}
23
David S. Miller9be12f92009-06-13 01:03:24 -070024static int ftrace_modify_code(unsigned long ip, u32 old, u32 new)
David Millerd05f5f92008-05-13 22:06:59 -070025{
David Millerd05f5f92008-05-13 22:06:59 -070026 u32 replaced;
27 int faulted;
28
29 __asm__ __volatile__(
30 "1: cas [%[ip]], %[old], %[new]\n"
31 " flush %[ip]\n"
32 " mov 0, %[faulted]\n"
33 "2:\n"
34 " .section .fixup,#alloc,#execinstr\n"
35 " .align 4\n"
36 "3: sethi %%hi(2b), %[faulted]\n"
37 " jmpl %[faulted] + %%lo(2b), %%g0\n"
38 " mov 1, %[faulted]\n"
39 " .previous\n"
40 " .section __ex_table,\"a\"\n"
41 " .align 4\n"
42 " .word 1b, 3b\n"
43 " .previous\n"
44 : "=r" (replaced), [faulted] "=r" (faulted)
45 : [new] "0" (new), [old] "r" (old), [ip] "r" (ip)
46 : "memory");
47
48 if (replaced != old && replaced != new)
49 faulted = 2;
50
51 return faulted;
52}
53
David S. Miller9be12f92009-06-13 01:03:24 -070054int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr)
55{
56 unsigned long ip = rec->ip;
57 u32 old, new;
58
59 old = ftrace_call_replace(ip, addr);
60 new = ftrace_nop;
61 return ftrace_modify_code(ip, old, new);
62}
63
64int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
65{
66 unsigned long ip = rec->ip;
67 u32 old, new;
68
69 old = ftrace_nop;
70 new = ftrace_call_replace(ip, addr);
71 return ftrace_modify_code(ip, old, new);
72}
73
Steven Rostedt15adc042008-10-23 09:33:08 -040074int ftrace_update_ftrace_func(ftrace_func_t func)
David Millerd05f5f92008-05-13 22:06:59 -070075{
76 unsigned long ip = (unsigned long)(&ftrace_call);
David S. Miller9be12f92009-06-13 01:03:24 -070077 u32 old, new;
David Millerd05f5f92008-05-13 22:06:59 -070078
David S. Miller9be12f92009-06-13 01:03:24 -070079 old = *(u32 *) &ftrace_call;
David Millerd05f5f92008-05-13 22:06:59 -070080 new = ftrace_call_replace(ip, (unsigned long)func);
81 return ftrace_modify_code(ip, old, new);
82}
83
David Millerd05f5f92008-05-13 22:06:59 -070084int __init ftrace_dyn_arch_init(void *data)
85{
David S. Miller9be12f92009-06-13 01:03:24 -070086 unsigned long *p = data;
87
88 *p = 0;
89
David Millerd05f5f92008-05-13 22:06:59 -070090 return 0;
91}
David S. Miller9be12f92009-06-13 01:03:24 -070092#endif
93