summaryrefslogtreecommitdiffstats
path: root/arch/parisc/kernel/ftrace.c
blob: c91f9c2e61ed25e605dacd34a6f270282c022e34 (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
// SPDX-License-Identifier: GPL-2.0
/*
 * Code for tracing calls in Linux kernel.
 * Copyright (C) 2009-2016 Helge Deller <deller@gmx.de>
 *
 * based on code for x86 which is:
 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
 *
 * future possible enhancements:
 *	- add CONFIG_STACK_TRACER
 */

#include <linux/init.h>
#include <linux/ftrace.h>
#include <linux/uaccess.h>
#include <linux/kprobes.h>
#include <linux/ptrace.h>
#include <linux/jump_label.h>

#include <asm/assembly.h>
#include <asm/sections.h>
#include <asm/ftrace.h>
#include <asm/patch.h>

#define __hot __section(".text.hot")

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
static DEFINE_STATIC_KEY_FALSE(ftrace_graph_enable);

/*
 * Hook the return address and push it in the stack of return addrs
 * in current thread info.
 */
static void __hot prepare_ftrace_return(unsigned long *parent,
					unsigned long self_addr)
{
	unsigned long old;
	extern int parisc_return_to_handler;

	if (unlikely(ftrace_graph_is_dead()))
		return;

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

	old = *parent;

	if (!function_graph_enter(old, self_addr, 0, NULL))
		/* activate parisc_return_to_handler() as return point */
		*parent = (unsigned long) &parisc_return_to_handler;
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

static ftrace_func_t ftrace_func;

asmlinkage void notrace __hot ftrace_function_trampoline(unsigned long parent,
				unsigned long self_addr,
				unsigned long org_sp_gr3,
				struct ftrace_regs *fregs)
{
	extern struct ftrace_ops *function_trace_op;

	ftrace_func(self_addr, parent, function_trace_op, fregs);

#ifdef CONFIG_FUNCTION_GRAPH_TRACER
	if (static_branch_unlikely(&ftrace_graph_enable)) {
		unsigned long *parent_rp;

		/* calculate pointer to %rp in stack */
		parent_rp = (unsigned long *) (org_sp_gr3 - RP_OFFSET);
		/* sanity check: parent_rp should hold parent */
		if (*parent_rp != parent)
			return;

		prepare_ftrace_return(parent_rp, self_addr);
		return;
	}
#endif
}

#if defined(CONFIG_DYNAMIC_FTRACE) && defined(CONFIG_FUNCTION_GRAPH_TRACER)
int ftrace_enable_ftrace_graph_caller(void)
{
	static_key_enable(&ftrace_graph_enable.key);
	return 0;
}

int ftrace_disable_ftrace_graph_caller(void)
{
	static_key_enable(&ftrace_graph_enable.key);
	return 0;
}
#endif

#ifdef CONFIG_DYNAMIC_FTRACE
int ftrace_update_ftrace_func(ftrace_func_t func)
{
	ftrace_func = func;
	return 0;
}

int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
			unsigned long addr)
{
	return 0;
}

unsigned long ftrace_call_adjust(unsigned long addr)
{
	return addr+(FTRACE_PATCHABLE_FUNCTION_SIZE-1)*4;
}

int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
	u32 insn[FTRACE_PATCHABLE_FUNCTION_SIZE];
	u32 *tramp;
	int size, ret, i;
	void *ip;

#ifdef CONFIG_64BIT
	unsigned long addr2 =
		(unsigned long)dereference_function_descriptor((void *)addr);

	u32 ftrace_trampoline[] = {
		0x73c10208, /* std,ma r1,100(sp) */
		0x0c2110c1, /* ldd -10(r1),r1 */
		0xe820d002, /* bve,n (r1) */
		addr2 >> 32,
		addr2 & 0xffffffff,
		0xe83f1fd7, /* b,l,n .-14,r1 */
	};

	u32 ftrace_trampoline_unaligned[] = {
		addr2 >> 32,
		addr2 & 0xffffffff,
		0x37de0200, /* ldo 100(sp),sp */
		0x73c13e01, /* std r1,-100(sp) */
		0x34213ff9, /* ldo -4(r1),r1 */
		0x50213fc1, /* ldd -20(r1),r1 */
		0xe820d002, /* bve,n (r1) */
		0xe83f1fcf, /* b,l,n .-20,r1 */
	};

	BUILD_BUG_ON(ARRAY_SIZE(ftrace_trampoline_unaligned) >
				FTRACE_PATCHABLE_FUNCTION_SIZE);
#else
	u32 ftrace_trampoline[] = {
		(u32)addr,
		0x6fc10080, /* stw,ma r1,40(sp) */
		0x48213fd1, /* ldw -18(r1),r1 */
		0xe820c002, /* bv,n r0(r1) */
		0xe83f1fdf, /* b,l,n .-c,r1 */
	};
#endif

	BUILD_BUG_ON(ARRAY_SIZE(ftrace_trampoline) >
				FTRACE_PATCHABLE_FUNCTION_SIZE);

	size = sizeof(ftrace_trampoline);
	tramp = ftrace_trampoline;

#ifdef CONFIG_64BIT
	if (rec->ip & 0x4) {
		size = sizeof(ftrace_trampoline_unaligned);
		tramp = ftrace_trampoline_unaligned;
	}
#endif

	ip = (void *)(rec->ip + 4 - size);

	ret = copy_from_kernel_nofault(insn, ip, size);
	if (ret)
		return ret;

	for (i = 0; i < size / 4; i++) {
		if (insn[i] != INSN_NOP)
			return -EINVAL;
	}

	__patch_text_multiple(ip, tramp, size);
	return 0;
}

int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
		    unsigned long addr)
{
	u32 insn[FTRACE_PATCHABLE_FUNCTION_SIZE];
	int i;

	for (i = 0; i < ARRAY_SIZE(insn); i++)
		insn[i] = INSN_NOP;

	__patch_text((void *)rec->ip, INSN_NOP);
	__patch_text_multiple((void *)rec->ip + 4 - sizeof(insn),
			      insn, sizeof(insn)-4);
	return 0;
}
#endif

#ifdef CONFIG_KPROBES_ON_FTRACE
void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
			   struct ftrace_ops *ops, struct ftrace_regs *fregs)
{
	struct kprobe_ctlblk *kcb;
	struct pt_regs *regs;
	struct kprobe *p;
	int bit;

	if (unlikely(kprobe_ftrace_disabled))
		return;

	bit = ftrace_test_recursion_trylock(ip, parent_ip);
	if (bit < 0)
		return;

	regs = ftrace_get_regs(fregs);
	p = get_kprobe((kprobe_opcode_t *)ip);
	if (unlikely(!p) || kprobe_disabled(p))
		goto out;

	if (kprobe_running()) {
		kprobes_inc_nmissed_count(p);
		goto out;
	}

	__this_cpu_write(current_kprobe, p);

	kcb = get_kprobe_ctlblk();
	kcb->kprobe_status = KPROBE_HIT_ACTIVE;

	regs->iaoq[0] = ip;
	regs->iaoq[1] = ip + 4;

	if (!p->pre_handler || !p->pre_handler(p, regs)) {
		regs->iaoq[0] = ip + 4;
		regs->iaoq[1] = ip + 8;

		if (unlikely(p->post_handler)) {
			kcb->kprobe_status = KPROBE_HIT_SSDONE;
			p->post_handler(p, regs, 0);
		}
	}
	__this_cpu_write(current_kprobe, NULL);
out:
	ftrace_test_recursion_unlock(bit);
}
NOKPROBE_SYMBOL(kprobe_ftrace_handler);

int arch_prepare_kprobe_ftrace(struct kprobe *p)
{
	p->ainsn.insn = NULL;
	return 0;
}
#endif