Commit | Line | Data |
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d05f5f99 DM |
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 | ||
395a59d0 AS |
8 | #include <asm/ftrace.h> |
9 | ||
9be12f9b | 10 | #ifdef CONFIG_DYNAMIC_FTRACE |
d05f5f99 DM |
11 | static const u32 ftrace_nop = 0x01000000; |
12 | ||
9be12f9b | 13 | static u32 ftrace_call_replace(unsigned long ip, unsigned long addr) |
d05f5f99 DM |
14 | { |
15 | static u32 call; | |
16 | s32 off; | |
17 | ||
18 | off = ((s32)addr - (s32)ip); | |
19 | call = 0x40000000 | ((u32)off >> 2); | |
20 | ||
9be12f9b | 21 | return call; |
d05f5f99 DM |
22 | } |
23 | ||
9be12f9b | 24 | static int ftrace_modify_code(unsigned long ip, u32 old, u32 new) |
d05f5f99 | 25 | { |
d05f5f99 DM |
26 | 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 | ||
9be12f9b DM |
54 | int 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 | ||
64 | int 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 | ||
15adc048 | 74 | int ftrace_update_ftrace_func(ftrace_func_t func) |
d05f5f99 DM |
75 | { |
76 | unsigned long ip = (unsigned long)(&ftrace_call); | |
9be12f9b | 77 | u32 old, new; |
d05f5f99 | 78 | |
9be12f9b | 79 | old = *(u32 *) &ftrace_call; |
d05f5f99 DM |
80 | new = ftrace_call_replace(ip, (unsigned long)func); |
81 | return ftrace_modify_code(ip, old, new); | |
82 | } | |
83 | ||
d05f5f99 DM |
84 | int __init ftrace_dyn_arch_init(void *data) |
85 | { | |
9be12f9b DM |
86 | unsigned long *p = data; |
87 | ||
88 | *p = 0; | |
89 | ||
d05f5f99 DM |
90 | return 0; |
91 | } | |
9be12f9b DM |
92 | #endif |
93 |