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15#include <linux/ftrace.h>
16#include <linux/uaccess.h>
17#include <linux/module.h>
18#include <linux/stop_machine.h>
19
20#include <asm/cacheflush.h>
21#include <asm/opcodes.h>
22#include <asm/ftrace.h>
23#include <asm/insn.h>
24#include <asm/set_memory.h>
25#include <asm/patch.h>
26
27#ifdef CONFIG_THUMB2_KERNEL
28#define NOP 0xf85deb04
29#else
30#define NOP 0xe8bd4000
31#endif
32
33#ifdef CONFIG_DYNAMIC_FTRACE
34
35static int __ftrace_modify_code(void *data)
36{
37 int *command = data;
38
39 ftrace_modify_all_code(*command);
40
41 return 0;
42}
43
44void arch_ftrace_update_code(int command)
45{
46 stop_machine(__ftrace_modify_code, &command, NULL);
47}
48
49static unsigned long ftrace_nop_replace(struct dyn_ftrace *rec)
50{
51 return NOP;
52}
53
54static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr)
55{
56 return addr;
57}
58
59int ftrace_arch_code_modify_prepare(void)
60{
61 return 0;
62}
63
64int ftrace_arch_code_modify_post_process(void)
65{
66
67 flush_tlb_all();
68 return 0;
69}
70
71static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr,
72 bool warn)
73{
74 return arm_gen_branch_link(pc, addr, warn);
75}
76
77static int ftrace_modify_code(unsigned long pc, unsigned long old,
78 unsigned long new, bool validate)
79{
80 unsigned long replaced;
81
82 if (IS_ENABLED(CONFIG_THUMB2_KERNEL))
83 old = __opcode_to_mem_thumb32(old);
84 else
85 old = __opcode_to_mem_arm(old);
86
87 if (validate) {
88 if (copy_from_kernel_nofault(&replaced, (void *)pc,
89 MCOUNT_INSN_SIZE))
90 return -EFAULT;
91
92 if (replaced != old)
93 return -EINVAL;
94 }
95
96 __patch_text((void *)pc, new);
97
98 return 0;
99}
100
101int ftrace_update_ftrace_func(ftrace_func_t func)
102{
103 unsigned long pc;
104 unsigned long new;
105 int ret;
106
107 pc = (unsigned long)&ftrace_call;
108 new = ftrace_call_replace(pc, (unsigned long)func, true);
109
110 ret = ftrace_modify_code(pc, 0, new, false);
111
112#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
113 if (!ret) {
114 pc = (unsigned long)&ftrace_regs_call;
115 new = ftrace_call_replace(pc, (unsigned long)func, true);
116
117 ret = ftrace_modify_code(pc, 0, new, false);
118 }
119#endif
120
121 return ret;
122}
123
124int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
125{
126 unsigned long new, old;
127 unsigned long ip = rec->ip;
128 unsigned long aaddr = adjust_address(rec, addr);
129 struct module *mod = NULL;
130
131#ifdef CONFIG_ARM_MODULE_PLTS
132 mod = rec->arch.mod;
133#endif
134
135 old = ftrace_nop_replace(rec);
136
137 new = ftrace_call_replace(ip, aaddr, !mod);
138#ifdef CONFIG_ARM_MODULE_PLTS
139 if (!new && mod) {
140 aaddr = get_module_plt(mod, ip, aaddr);
141 new = ftrace_call_replace(ip, aaddr, true);
142 }
143#endif
144
145 return ftrace_modify_code(rec->ip, old, new, true);
146}
147
148#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
149
150int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
151 unsigned long addr)
152{
153 unsigned long new, old;
154 unsigned long ip = rec->ip;
155
156 old = ftrace_call_replace(ip, adjust_address(rec, old_addr), true);
157
158 new = ftrace_call_replace(ip, adjust_address(rec, addr), true);
159
160 return ftrace_modify_code(rec->ip, old, new, true);
161}
162
163#endif
164
165int ftrace_make_nop(struct module *mod,
166 struct dyn_ftrace *rec, unsigned long addr)
167{
168 unsigned long aaddr = adjust_address(rec, addr);
169 unsigned long ip = rec->ip;
170 unsigned long old;
171 unsigned long new;
172 int ret;
173
174#ifdef CONFIG_ARM_MODULE_PLTS
175
176 if (!mod)
177 mod = rec->arch.mod;
178 else
179 rec->arch.mod = mod;
180#endif
181
182 old = ftrace_call_replace(ip, aaddr,
183 !IS_ENABLED(CONFIG_ARM_MODULE_PLTS) || !mod);
184#ifdef CONFIG_ARM_MODULE_PLTS
185 if (!old && mod) {
186 aaddr = get_module_plt(mod, ip, aaddr);
187 old = ftrace_call_replace(ip, aaddr, true);
188 }
189#endif
190
191 new = ftrace_nop_replace(rec);
192 ret = ftrace_modify_code(ip, old, new, true);
193
194 return ret;
195}
196
197int __init ftrace_dyn_arch_init(void)
198{
199 return 0;
200}
201#endif
202
203#ifdef CONFIG_FUNCTION_GRAPH_TRACER
204void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
205 unsigned long frame_pointer)
206{
207 unsigned long return_hooker = (unsigned long) &return_to_handler;
208 unsigned long old;
209
210 if (unlikely(atomic_read(¤t->tracing_graph_pause)))
211 return;
212
213 old = *parent;
214 *parent = return_hooker;
215
216 if (function_graph_enter(old, self_addr, frame_pointer, NULL))
217 *parent = old;
218}
219
220#ifdef CONFIG_DYNAMIC_FTRACE
221extern unsigned long ftrace_graph_call;
222extern unsigned long ftrace_graph_call_old;
223extern void ftrace_graph_caller_old(void);
224extern unsigned long ftrace_graph_regs_call;
225extern void ftrace_graph_regs_caller(void);
226
227static int __ftrace_modify_caller(unsigned long *callsite,
228 void (*func) (void), bool enable)
229{
230 unsigned long caller_fn = (unsigned long) func;
231 unsigned long pc = (unsigned long) callsite;
232 unsigned long branch = arm_gen_branch(pc, caller_fn);
233 unsigned long nop = 0xe1a00000;
234 unsigned long old = enable ? nop : branch;
235 unsigned long new = enable ? branch : nop;
236
237 return ftrace_modify_code(pc, old, new, true);
238}
239
240static int ftrace_modify_graph_caller(bool enable)
241{
242 int ret;
243
244 ret = __ftrace_modify_caller(&ftrace_graph_call,
245 ftrace_graph_caller,
246 enable);
247
248#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
249 if (!ret)
250 ret = __ftrace_modify_caller(&ftrace_graph_regs_call,
251 ftrace_graph_regs_caller,
252 enable);
253#endif
254
255
256 return ret;
257}
258
259int ftrace_enable_ftrace_graph_caller(void)
260{
261 return ftrace_modify_graph_caller(true);
262}
263
264int ftrace_disable_ftrace_graph_caller(void)
265{
266 return ftrace_modify_graph_caller(false);
267}
268#endif
269#endif
270