1 // SPDX-License-Identifier: GPL-2.0 1
2 /*
3 * Copyright (C) 2022 Loongson Technology Corp
4 */
5
6 #include <linux/init.h>
7 #include <linux/ftrace.h>
8 #include <linux/syscalls.h>
9 #include <linux/uaccess.h>
10
11 #include <asm/asm.h>
12 #include <asm/asm-offsets.h>
13 #include <asm/cacheflush.h>
14 #include <asm/inst.h>
15 #include <asm/loongarch.h>
16 #include <asm/syscall.h>
17
18 #include <asm-generic/sections.h>
19
20 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
21
22 /*
23 * As `call _mcount` follows LoongArch psABI,
24 * stack operation can be found before this in
25 */
26
27 static int ftrace_get_parent_ra_addr(unsigned
28 {
29 int limit = 32;
30 union loongarch_instruction *insn;
31
32 insn = (union loongarch_instruction *)
33
34 do {
35 insn--;
36 limit--;
37
38 if (is_ra_save_ins(insn))
39 *ra_off = -((1 << 12)
40
41 } while (!is_stack_alloc_ins(insn) &&
42
43 if (!limit)
44 return -EINVAL;
45
46 return 0;
47 }
48
49 void prepare_ftrace_return(unsigned long self_
50 unsigned long callsite_sp, uns
51 {
52 int ra_off;
53 unsigned long return_hooker = (unsigne
54
55 if (unlikely(ftrace_graph_is_dead()))
56 return;
57
58 if (unlikely(atomic_read(¤t->tra
59 return;
60
61 if (ftrace_get_parent_ra_addr(self_add
62 goto out;
63
64 if (!function_graph_enter(old, self_ad
65 *(unsigned long *)(callsite_sp
66
67 return;
68
69 out:
70 ftrace_graph_stop();
71 WARN_ON(1);
72 }
73 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
74
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