summaryrefslogtreecommitdiffstats
path: root/arch/nds32/kernel/ftrace.c
blob: 0e23e3a8df6b556e8331c03e3118be4c2c31e7a1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
// SPDX-License-Identifier: GPL-2.0

#include <linux/ftrace.h>
#include <linux/uaccess.h>
#include <asm/cacheflush.h>

#ifndef CONFIG_DYNAMIC_FTRACE
extern void (*ftrace_trace_function)(unsigned long, unsigned long,
				     struct ftrace_ops*, struct pt_regs*);
extern void ftrace_graph_caller(void);

noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,
				  struct ftrace_ops *op, struct ftrace_regs *fregs)
{
	__asm__ ("");  /* avoid to optimize as pure function */
}

noinline void _mcount(unsigned long parent_ip)
{
	/* save all state by the compiler prologue */

	unsigned long ip = (unsigned long)__builtin_return_address(0);

	if (ftrace_trace_function != ftrace_stub)
		ftrace_trace_function(ip - MCOUNT_INSN_SIZE, parent_ip,
				      NULL, NULL);

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
	if (ftrace_graph_return != (trace_func_graph_ret_t)ftrace_stub
	    || ftrace_graph_entry != ftrace_graph_entry_stub)
		ftrace_graph_caller();
#endif

	/* restore all state by the compiler epilogue */
}
EXPORT_SYMBOL(_mcount);

#else /* CONFIG_DYNAMIC_FTRACE */

noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,
				  struct ftrace_ops *op, struct ftrace_regs *fregs)
{
	__asm__ ("");  /* avoid to optimize as pure function */
}

noinline void __naked _mcount(unsigned long parent_ip)
{
	__asm__ ("");  /* avoid to optimize as pure function */
}
EXPORT_SYMBOL(_mcount);

#define XSTR(s) STR(s)
#define STR(s) #s
void _ftrace_caller(unsigned long parent_ip)
{
	/* save all state needed by the compiler prologue */

	/*
	 * prepare arguments for real tracing function
	 * first  arg : __builtin_return_address(0) - MCOUNT_INSN_SIZE
	 * second arg : parent_ip
	 */
	__asm__ __volatile__ (
		"move $r1, %0				   \n\t"
		"addi $r0, %1, #-" XSTR(MCOUNT_INSN_SIZE) "\n\t"
		:
		: "r" (parent_ip), "r" (__builtin_return_address(0)));

	/* a placeholder for the call to a real tracing function */
	__asm__ __volatile__ (
		"ftrace_call:		\n\t"
		"nop			\n\t"
		"nop			\n\t"
		"nop			\n\t");

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
	/* a placeholder for the call to ftrace_graph_caller */
	__asm__ __volatile__ (
		"ftrace_graph_call:	\n\t"
		"nop			\n\t"
		"nop			\n\t"
		"nop			\n\t");
#endif
	/* restore all state needed by the compiler epilogue */
}

int __init ftrace_dyn_arch_init(void)
{
	return 0;
}

static unsigned long gen_sethi_insn(unsigned long addr)
{
	unsigned long opcode = 0x46000000;
	unsigned long imm = addr >> 12;
	unsigned long rt_num = 0xf << 20;

	return ENDIAN_CONVERT(opcode | rt_num | imm);
}

static unsigned long gen_ori_insn(unsigned long addr)
{
	unsigned long opcode = 0x58000000;
	unsigned long imm = addr & 0x0000fff;
	unsigned long rt_num = 0xf << 20;
	unsigned long ra_num = 0xf << 15;

	return ENDIAN_CONVERT(opcode | rt_num | ra_num | imm);
}

static unsigned long gen_jral_insn(unsigned long addr)
{
	unsigned long opcode = 0x4a000001;
	unsigned long rt_num = 0x1e << 20;
	unsigned long rb_num = 0xf << 10;

	return ENDIAN_CONVERT(opcode | rt_num | rb_num);
}

static void ftrace_gen_call_insn(unsigned long *call_insns,
				 unsigned long addr)
{
	call_insns[0] = gen_sethi_insn(addr); /* sethi $r15, imm20u       */
	call_insns[1] = gen_ori_insn(addr);   /* ori   $r15, $r15, imm15u */
	call_insns[2] = gen_jral_insn(addr);  /* jral  $lp,  $r15         */
}

static int __ftrace_modify_code(unsigned long pc, unsigned long *old_insn,
				unsigned long *new_insn, bool validate)
{
	unsigned long orig_insn[3];

	if (validate) {
		if (copy_from_kernel_nofault(orig_insn, (void *)pc,
				MCOUNT_INSN_SIZE))
			return -EFAULT;
		if (memcmp(orig_insn, old_insn, MCOUNT_INSN_SIZE))
			return -EINVAL;
	}

	if (copy_to_kernel_nofault((void *)pc, new_insn, MCOUNT_INSN_SIZE))
		return -EPERM;

	return 0;
}

static int ftrace_modify_code(unsigned long pc, unsigned long *old_insn,
			      unsigned long *new_insn, bool validate)
{
	int ret;

	ret = __ftrace_modify_code(pc, old_insn, new_insn, validate);
	if (ret)
		return ret;

	flush_icache_range(pc, pc + MCOUNT_INSN_SIZE);

	return ret;
}

int ftrace_update_ftrace_func(ftrace_func_t func)
{
	unsigned long pc = (unsigned long)&ftrace_call;
	unsigned long old_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
	unsigned long new_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};

	if (func != ftrace_stub)
		ftrace_gen_call_insn(new_insn, (unsigned long)func);

	return ftrace_modify_code(pc, old_insn, new_insn, false);
}

int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
	unsigned long pc = rec->ip;
	unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
	unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};

	ftrace_gen_call_insn(call_insn, addr);

	return ftrace_modify_code(pc, nop_insn, call_insn, true);
}

int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
		    unsigned long addr)
{
	unsigned long pc = rec->ip;
	unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
	unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};

	ftrace_gen_call_insn(call_insn, addr);

	return ftrace_modify_code(pc, call_insn, nop_insn, true);
}
#endif /* CONFIG_DYNAMIC_FTRACE */

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
			   unsigned long frame_pointer)
{
	unsigned long return_hooker = (unsigned long)&return_to_handler;
	unsigned long old;

	if (unlikely(atomic_read(&current->tracing_graph_pause)))
		return;

	old = *parent;

	if (!function_graph_enter(old, self_addr, frame_pointer, NULL))
		*parent = return_hooker;
}

noinline void ftrace_graph_caller(void)
{
	unsigned long *parent_ip =
		(unsigned long *)(__builtin_frame_address(2) - 4);

	unsigned long selfpc =
		(unsigned long)(__builtin_return_address(1) - MCOUNT_INSN_SIZE);

	unsigned long frame_pointer =
		(unsigned long)__builtin_frame_address(3);

	prepare_ftrace_return(parent_ip, selfpc, frame_pointer);
}

extern unsigned long ftrace_return_to_handler(unsigned long frame_pointer);
void __naked return_to_handler(void)
{
	__asm__ __volatile__ (
		/* save state needed by the ABI     */
		"smw.adm $r0,[$sp],$r1,#0x0  \n\t"

		/* get original return address      */
		"move $r0, $fp               \n\t"
		"bal ftrace_return_to_handler\n\t"
		"move $lp, $r0               \n\t"

		/* restore state needed by the ABI  */
		"lmw.bim $r0,[$sp],$r1,#0x0  \n\t");
}

#ifdef CONFIG_DYNAMIC_FTRACE
extern unsigned long ftrace_graph_call;

static int ftrace_modify_graph_caller(bool enable)
{
	unsigned long pc = (unsigned long)&ftrace_graph_call;
	unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};
	unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP};

	ftrace_gen_call_insn(call_insn, (unsigned long)ftrace_graph_caller);

	if (enable)
		return ftrace_modify_code(pc, nop_insn, call_insn, true);
	else
		return ftrace_modify_code(pc, call_insn, nop_insn, true);
}

int ftrace_enable_ftrace_graph_caller(void)
{
	return ftrace_modify_graph_caller(true);
}

int ftrace_disable_ftrace_graph_caller(void)
{
	return ftrace_modify_graph_caller(false);
}
#endif /* CONFIG_DYNAMIC_FTRACE */

#endif /* CONFIG_FUNCTION_GRAPH_TRACER */


#ifdef CONFIG_TRACE_IRQFLAGS
noinline void __trace_hardirqs_off(void)
{
	trace_hardirqs_off();
}
noinline void __trace_hardirqs_on(void)
{
	trace_hardirqs_on();
}
#endif /* CONFIG_TRACE_IRQFLAGS */