Merge branch 'timers/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6] / arch / sparc64 / kernel / ftrace.c
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>
7
8 #include <asm/ftrace.h>
9
10 static const u32 ftrace_nop = 0x01000000;
11
12 notrace unsigned char *ftrace_nop_replace(void)
13 {
14         return (char *)&ftrace_nop;
15 }
16
17 notrace unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
18 {
19         static u32 call;
20         s32 off;
21
22         off = ((s32)addr - (s32)ip);
23         call = 0x40000000 | ((u32)off >> 2);
24
25         return (unsigned char *) &call;
26 }
27
28 notrace int
29 ftrace_modify_code(unsigned long ip, unsigned char *old_code,
30                    unsigned char *new_code)
31 {
32         u32 old = *(u32 *)old_code;
33         u32 new = *(u32 *)new_code;
34         u32 replaced;
35         int faulted;
36
37         __asm__ __volatile__(
38         "1:     cas     [%[ip]], %[old], %[new]\n"
39         "       flush   %[ip]\n"
40         "       mov     0, %[faulted]\n"
41         "2:\n"
42         "       .section .fixup,#alloc,#execinstr\n"
43         "       .align  4\n"
44         "3:     sethi   %%hi(2b), %[faulted]\n"
45         "       jmpl    %[faulted] + %%lo(2b), %%g0\n"
46         "        mov    1, %[faulted]\n"
47         "       .previous\n"
48         "       .section __ex_table,\"a\"\n"
49         "       .align  4\n"
50         "       .word   1b, 3b\n"
51         "       .previous\n"
52         : "=r" (replaced), [faulted] "=r" (faulted)
53         : [new] "0" (new), [old] "r" (old), [ip] "r" (ip)
54         : "memory");
55
56         if (replaced != old && replaced != new)
57                 faulted = 2;
58
59         return faulted;
60 }
61
62 notrace int ftrace_update_ftrace_func(ftrace_func_t func)
63 {
64         unsigned long ip = (unsigned long)(&ftrace_call);
65         unsigned char old[MCOUNT_INSN_SIZE], *new;
66
67         memcpy(old, &ftrace_call, MCOUNT_INSN_SIZE);
68         new = ftrace_call_replace(ip, (unsigned long)func);
69         return ftrace_modify_code(ip, old, new);
70 }
71
72 notrace int ftrace_mcount_set(unsigned long *data)
73 {
74         unsigned long ip = (long)(&mcount_call);
75         unsigned long *addr = data;
76         unsigned char old[MCOUNT_INSN_SIZE], *new;
77
78         /*
79          * Replace the mcount stub with a pointer to the
80          * ip recorder function.
81          */
82         memcpy(old, &mcount_call, MCOUNT_INSN_SIZE);
83         new = ftrace_call_replace(ip, *addr);
84         *addr = ftrace_modify_code(ip, old, new);
85
86         return 0;
87 }
88
89
90 int __init ftrace_dyn_arch_init(void *data)
91 {
92         ftrace_mcount_set(data);
93         return 0;
94 }