Loading...
Note: File does not exist in v4.17.
1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/ftrace.h>
4#include <linux/uaccess.h>
5#include <asm/cacheflush.h>
6
7#ifndef CONFIG_DYNAMIC_FTRACE
8extern void (*ftrace_trace_function)(unsigned long, unsigned long,
9 struct ftrace_ops*, struct pt_regs*);
10extern void ftrace_graph_caller(void);
11
12noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,
13 struct ftrace_ops *op, struct pt_regs *regs)
14{
15 __asm__ (""); /* avoid to optimize as pure function */
16}
17
18noinline void _mcount(unsigned long parent_ip)
19{
20 /* save all state by the compiler prologue */
21
22 unsigned long ip = (unsigned long)__builtin_return_address(0);
23
24 if (ftrace_trace_function != ftrace_stub)
25 ftrace_trace_function(ip - MCOUNT_INSN_SIZE, parent_ip,
26 NULL, NULL);
27
28#ifdef CONFIG_FUNCTION_GRAPH_TRACER
29 if (ftrace_graph_return != (trace_func_graph_ret_t)ftrace_stub
30 || ftrace_graph_entry != ftrace_graph_entry_stub)
31 ftrace_graph_caller();
32#endif
33
34 /* restore all state by the compiler epilogue */
35}
36EXPORT_SYMBOL(_mcount);
37
38#else /* CONFIG_DYNAMIC_FTRACE */
39
40noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,
41 struct ftrace_ops *op, struct pt_regs *regs)
42{
43 __asm__ (""); /* avoid to optimize as pure function */
44}
45
46noinline void __naked _mcount(unsigned long parent_ip)
47{
48 __asm__ (""); /* avoid to optimize as pure function */
49}
50EXPORT_SYMBOL(_mcount);
51
52#define XSTR(s) STR(s)
53#define STR(s) #s
54void _ftrace_caller(unsigned long parent_ip)
55{
56 /* save all state needed by the compiler prologue */
57
58 /*
59 * prepare arguments for real tracing function
60 * first arg : __builtin_return_address(0) - MCOUNT_INSN_SIZE
61 * second arg : parent_ip
62 */
63 __asm__ __volatile__ (
64 "move $r1, %0 \n\t"
65 "addi $r0, %1, #-" XSTR(MCOUNT_INSN_SIZE) "\n\t"
66 :
67 : "r" (parent_ip), "r" (__builtin_return_address(0)));
68
69 /* a placeholder for the call to a real tracing function */
70 __asm__ __volatile__ (
71 "ftrace_call: \n\t"
72 "nop \n\t"
73 "nop \n\t"
74 "nop \n\t");
75
76#ifdef CONFIG_FUNCTION_GRAPH_TRACER
77 /* a placeholder for the call to ftrace_graph_caller */
78 __asm__ __volatile__ (
79 "ftrace_graph_call: \n\t"
80 "nop \n\t"
81 "nop \n\t"
82 "nop \n\t");
83#endif
84 /* restore all state needed by the compiler epilogue */
85}
86
87int __init ftrace_dyn_arch_init(void)
88{
89 return 0;
90}
91
92int ftrace_arch_code_modify_prepare(void)
93{
94 set_all_modules_text_rw();
95 return 0;
96}
97
98int ftrace_arch_code_modify_post_process(void)
99{
100 set_all_modules_text_ro();
101 return 0;
102}
103
104static unsigned long gen_sethi_insn(unsigned long addr)
105{
106 unsigned long opcode = 0x46000000;
107 unsigned long imm = addr >> 12;
108 unsigned long rt_num = 0xf << 20;
109
110 return ENDIAN_CONVERT(opcode | rt_num | imm);
111}
112
113static unsigned long gen_ori_insn(unsigned long addr)
114{
115 unsigned long opcode = 0x58000000;
116 unsigned long imm = addr & 0x0000fff;
117 unsigned long rt_num = 0xf << 20;
118 unsigned long ra_num = 0xf << 15;
119
120 return ENDIAN_CONVERT(opcode | rt_num | ra_num | imm);
121}
122
123static unsigned long gen_jral_insn(unsigned long addr)
124{
125 unsigned long opcode = 0x4a000001;
126 unsigned long rt_num = 0x1e << 20;
127 unsigned long rb_num = 0xf << 10;
128
129 return ENDIAN_CONVERT(opcode | rt_num | rb_num);
130}
131
132static void ftrace_gen_call_insn(unsigned long *call_insns,
133 unsigned long addr)
134{
135 call_insns[0] = gen_sethi_insn(addr); /* sethi $r15, imm20u */
136 call_insns[1] = gen_ori_insn(addr); /* ori $r15, $r15, imm15u */
137 call_insns[2] = gen_jral_insn(addr); /* jral $lp, $r15 */
138}
139
140static int __ftrace_modify_code(unsigned long pc, unsigned long *old_insn,
141 unsigned long *new_insn, bool validate)
142{
143 unsigned long orig_insn[3];
144
145 if (validate) {
146 if (probe_kernel_read(orig_insn, (void *)pc, MCOUNT_INSN_SIZE))
147 return -EFAULT;
148 if (memcmp(orig_insn, old_insn, MCOUNT_INSN_SIZE))
149 return -EINVAL;
150 }
151
152 if (probe_kernel_write((void *)pc, new_insn, MCOUNT_INSN_SIZE))
153 return -EPERM;
154
155 return 0;
156}
157
158static int ftrace_modify_code(unsigned long pc, unsigned long *old_insn,
159 unsigned long *new_insn, bool validate)
160{
161 int ret;
162
163 ret = __ftrace_modify_code(pc, old_insn, new_insn, validate);
164 if (ret)
165 return ret;
166
167 flush_icache_range(pc, pc + MCOUNT_INSN_SIZE);
168
169 return ret;
170}
171
172int ftrace_update_ftrace_func(ftrace_func_t func)
173{
174 unsigned long pc = (unsigned long)&ftrace_call;
175 unsigned long old_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
176 unsigned long new_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
177
178 if (func != ftrace_stub)
179 ftrace_gen_call_insn(new_insn, (unsigned long)func);
180
181 return ftrace_modify_code(pc, old_insn, new_insn, false);
182}
183
184int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
185{
186 unsigned long pc = rec->ip;
187 unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
188 unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
189
190 ftrace_gen_call_insn(call_insn, addr);
191
192 return ftrace_modify_code(pc, nop_insn, call_insn, true);
193}
194
195int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
196 unsigned long addr)
197{
198 unsigned long pc = rec->ip;
199 unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
200 unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
201
202 ftrace_gen_call_insn(call_insn, addr);
203
204 return ftrace_modify_code(pc, call_insn, nop_insn, true);
205}
206#endif /* CONFIG_DYNAMIC_FTRACE */
207
208#ifdef CONFIG_FUNCTION_GRAPH_TRACER
209void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
210 unsigned long frame_pointer)
211{
212 unsigned long return_hooker = (unsigned long)&return_to_handler;
213 unsigned long old;
214
215 if (unlikely(atomic_read(¤t->tracing_graph_pause)))
216 return;
217
218 old = *parent;
219
220 if (!function_graph_enter(old, self_addr, frame_pointer, NULL))
221 *parent = return_hooker;
222}
223
224noinline void ftrace_graph_caller(void)
225{
226 unsigned long *parent_ip =
227 (unsigned long *)(__builtin_frame_address(2) - 4);
228
229 unsigned long selfpc =
230 (unsigned long)(__builtin_return_address(1) - MCOUNT_INSN_SIZE);
231
232 unsigned long frame_pointer =
233 (unsigned long)__builtin_frame_address(3);
234
235 prepare_ftrace_return(parent_ip, selfpc, frame_pointer);
236}
237
238extern unsigned long ftrace_return_to_handler(unsigned long frame_pointer);
239void __naked return_to_handler(void)
240{
241 __asm__ __volatile__ (
242 /* save state needed by the ABI */
243 "smw.adm $r0,[$sp],$r1,#0x0 \n\t"
244
245 /* get original return address */
246 "move $r0, $fp \n\t"
247 "bal ftrace_return_to_handler\n\t"
248 "move $lp, $r0 \n\t"
249
250 /* restore state nedded by the ABI */
251 "lmw.bim $r0,[$sp],$r1,#0x0 \n\t");
252}
253
254#ifdef CONFIG_DYNAMIC_FTRACE
255extern unsigned long ftrace_graph_call;
256
257static int ftrace_modify_graph_caller(bool enable)
258{
259 unsigned long pc = (unsigned long)&ftrace_graph_call;
260 unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
261 unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
262
263 ftrace_gen_call_insn(call_insn, (unsigned long)ftrace_graph_caller);
264
265 if (enable)
266 return ftrace_modify_code(pc, nop_insn, call_insn, true);
267 else
268 return ftrace_modify_code(pc, call_insn, nop_insn, true);
269}
270
271int ftrace_enable_ftrace_graph_caller(void)
272{
273 return ftrace_modify_graph_caller(true);
274}
275
276int ftrace_disable_ftrace_graph_caller(void)
277{
278 return ftrace_modify_graph_caller(false);
279}
280#endif /* CONFIG_DYNAMIC_FTRACE */
281
282#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
283
284
285#ifdef CONFIG_TRACE_IRQFLAGS
286noinline void __trace_hardirqs_off(void)
287{
288 trace_hardirqs_off();
289}
290noinline void __trace_hardirqs_on(void)
291{
292 trace_hardirqs_on();
293}
294#endif /* CONFIG_TRACE_IRQFLAGS */