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> | |
c658ad1b | 7 | #include <trace/syscall.h> |
d05f5f99 | 8 | |
395a59d0 AS |
9 | #include <asm/ftrace.h> |
10 | ||
9be12f9b | 11 | #ifdef CONFIG_DYNAMIC_FTRACE |
d05f5f99 DM |
12 | static const u32 ftrace_nop = 0x01000000; |
13 | ||
9be12f9b | 14 | static u32 ftrace_call_replace(unsigned long ip, unsigned long addr) |
d05f5f99 DM |
15 | { |
16 | static u32 call; | |
17 | s32 off; | |
18 | ||
19 | off = ((s32)addr - (s32)ip); | |
20 | call = 0x40000000 | ((u32)off >> 2); | |
21 | ||
9be12f9b | 22 | return call; |
d05f5f99 DM |
23 | } |
24 | ||
9be12f9b | 25 | static int ftrace_modify_code(unsigned long ip, u32 old, u32 new) |
d05f5f99 | 26 | { |
d05f5f99 DM |
27 | u32 replaced; |
28 | int faulted; | |
29 | ||
30 | __asm__ __volatile__( | |
31 | "1: cas [%[ip]], %[old], %[new]\n" | |
32 | " flush %[ip]\n" | |
33 | " mov 0, %[faulted]\n" | |
34 | "2:\n" | |
35 | " .section .fixup,#alloc,#execinstr\n" | |
36 | " .align 4\n" | |
37 | "3: sethi %%hi(2b), %[faulted]\n" | |
38 | " jmpl %[faulted] + %%lo(2b), %%g0\n" | |
39 | " mov 1, %[faulted]\n" | |
40 | " .previous\n" | |
41 | " .section __ex_table,\"a\"\n" | |
42 | " .align 4\n" | |
43 | " .word 1b, 3b\n" | |
44 | " .previous\n" | |
45 | : "=r" (replaced), [faulted] "=r" (faulted) | |
46 | : [new] "0" (new), [old] "r" (old), [ip] "r" (ip) | |
47 | : "memory"); | |
48 | ||
49 | if (replaced != old && replaced != new) | |
50 | faulted = 2; | |
51 | ||
52 | return faulted; | |
53 | } | |
54 | ||
9be12f9b DM |
55 | int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) |
56 | { | |
57 | unsigned long ip = rec->ip; | |
58 | u32 old, new; | |
59 | ||
60 | old = ftrace_call_replace(ip, addr); | |
61 | new = ftrace_nop; | |
62 | return ftrace_modify_code(ip, old, new); | |
63 | } | |
64 | ||
65 | int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) | |
66 | { | |
67 | unsigned long ip = rec->ip; | |
68 | u32 old, new; | |
69 | ||
70 | old = ftrace_nop; | |
71 | new = ftrace_call_replace(ip, addr); | |
72 | return ftrace_modify_code(ip, old, new); | |
73 | } | |
74 | ||
15adc048 | 75 | int ftrace_update_ftrace_func(ftrace_func_t func) |
d05f5f99 DM |
76 | { |
77 | unsigned long ip = (unsigned long)(&ftrace_call); | |
9be12f9b | 78 | u32 old, new; |
d05f5f99 | 79 | |
9be12f9b | 80 | old = *(u32 *) &ftrace_call; |
d05f5f99 DM |
81 | new = ftrace_call_replace(ip, (unsigned long)func); |
82 | return ftrace_modify_code(ip, old, new); | |
83 | } | |
84 | ||
d05f5f99 DM |
85 | int __init ftrace_dyn_arch_init(void *data) |
86 | { | |
9be12f9b DM |
87 | unsigned long *p = data; |
88 | ||
89 | *p = 0; | |
90 | ||
d05f5f99 DM |
91 | return 0; |
92 | } | |
9be12f9b | 93 | #endif |