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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
d75f054a HD |
2 | /* |
3 | * Code for tracing calls in Linux kernel. | |
366dd4ea | 4 | * Copyright (C) 2009-2016 Helge Deller <deller@gmx.de> |
d75f054a HD |
5 | * |
6 | * based on code for x86 which is: | |
7 | * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> | |
8 | * | |
9 | * future possible enhancements: | |
10 | * - add CONFIG_DYNAMIC_FTRACE | |
11 | * - add CONFIG_STACK_TRACER | |
12 | */ | |
13 | ||
14 | #include <linux/init.h> | |
15 | #include <linux/ftrace.h> | |
16 | ||
366dd4ea | 17 | #include <asm/assembly.h> |
d75f054a HD |
18 | #include <asm/sections.h> |
19 | #include <asm/ftrace.h> | |
20 | ||
21 | ||
4df3c9ec HD |
22 | #define __hot __attribute__ ((__section__ (".text.hot"))) |
23 | ||
d75f054a | 24 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
d75f054a HD |
25 | /* |
26 | * Hook the return address and push it in the stack of return addrs | |
27 | * in current thread info. | |
28 | */ | |
4df3c9ec HD |
29 | static void __hot prepare_ftrace_return(unsigned long *parent, |
30 | unsigned long self_addr) | |
d75f054a HD |
31 | { |
32 | unsigned long old; | |
d75f054a | 33 | struct ftrace_graph_ent trace; |
366dd4ea | 34 | extern int parisc_return_to_handler; |
d75f054a | 35 | |
3a46588e SRRH |
36 | if (unlikely(ftrace_graph_is_dead())) |
37 | return; | |
38 | ||
d75f054a HD |
39 | if (unlikely(atomic_read(¤t->tracing_graph_pause))) |
40 | return; | |
41 | ||
42 | old = *parent; | |
d75f054a | 43 | |
366dd4ea HD |
44 | trace.func = self_addr; |
45 | trace.depth = current->curr_ret_stack + 1; | |
d75f054a | 46 | |
366dd4ea HD |
47 | /* Only trace if the calling function expects to */ |
48 | if (!ftrace_graph_entry(&trace)) | |
d75f054a | 49 | return; |
d75f054a | 50 | |
366dd4ea | 51 | if (ftrace_push_return_trace(old, self_addr, &trace.depth, |
9a7c348b | 52 | 0, NULL) == -EBUSY) |
366dd4ea | 53 | return; |
d75f054a | 54 | |
366dd4ea HD |
55 | /* activate parisc_return_to_handler() as return point */ |
56 | *parent = (unsigned long) &parisc_return_to_handler; | |
d75f054a | 57 | } |
d75f054a HD |
58 | #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |
59 | ||
4df3c9ec | 60 | void notrace __hot ftrace_function_trampoline(unsigned long parent, |
d75f054a HD |
61 | unsigned long self_addr, |
62 | unsigned long org_sp_gr3) | |
63 | { | |
366dd4ea HD |
64 | extern ftrace_func_t ftrace_trace_function; /* depends on CONFIG_DYNAMIC_FTRACE */ |
65 | extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace); | |
d75f054a | 66 | |
d75f054a | 67 | if (ftrace_trace_function != ftrace_stub) { |
366dd4ea HD |
68 | /* struct ftrace_ops *op, struct pt_regs *regs); */ |
69 | ftrace_trace_function(parent, self_addr, NULL, NULL); | |
d75f054a HD |
70 | return; |
71 | } | |
366dd4ea | 72 | |
d75f054a | 73 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
366dd4ea HD |
74 | if (ftrace_graph_return != (trace_func_graph_ret_t) ftrace_stub || |
75 | ftrace_graph_entry != ftrace_graph_entry_stub) { | |
d75f054a HD |
76 | unsigned long *parent_rp; |
77 | ||
d75f054a | 78 | /* calculate pointer to %rp in stack */ |
366dd4ea | 79 | parent_rp = (unsigned long *) (org_sp_gr3 - RP_OFFSET); |
d75f054a HD |
80 | /* sanity check: parent_rp should hold parent */ |
81 | if (*parent_rp != parent) | |
82 | return; | |
366dd4ea | 83 | |
d75f054a HD |
84 | prepare_ftrace_return(parent_rp, self_addr); |
85 | return; | |
86 | } | |
87 | #endif | |
88 | } | |
89 |