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1/*
2 * Ftrace support for Microblaze.
3 *
4 * Copyright (C) 2009 Michal Simek <monstr@monstr.eu>
5 * Copyright (C) 2009 PetaLogix
6 *
7 * Based on MIPS and PowerPC ftrace code
8 *
9 * This file is subject to the terms and conditions of the GNU General Public
10 * License. See the file "COPYING" in the main directory of this archive
11 * for more details.
12 */
13
14#include <asm/cacheflush.h>
15#include <linux/ftrace.h>
16
17#ifdef CONFIG_FUNCTION_GRAPH_TRACER
18/*
19 * Hook the return address and push it in the stack of return addrs
20 * in current thread info.
21 */
22void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
23{
24 unsigned long old;
25 int faulted, err;
26 struct ftrace_graph_ent trace;
27 unsigned long return_hooker = (unsigned long)
28 &return_to_handler;
29
30 if (unlikely(ftrace_graph_is_dead()))
31 return;
32
33 if (unlikely(atomic_read(¤t->tracing_graph_pause)))
34 return;
35
36 /*
37 * Protect against fault, even if it shouldn't
38 * happen. This tool is too much intrusive to
39 * ignore such a protection.
40 */
41 asm volatile(" 1: lwi %0, %2, 0;" \
42 "2: swi %3, %2, 0;" \
43 " addik %1, r0, 0;" \
44 "3:" \
45 " .section .fixup, \"ax\";" \
46 "4: brid 3b;" \
47 " addik %1, r0, 1;" \
48 " .previous;" \
49 " .section __ex_table,\"a\";" \
50 " .word 1b,4b;" \
51 " .word 2b,4b;" \
52 " .previous;" \
53 : "=&r" (old), "=r" (faulted)
54 : "r" (parent), "r" (return_hooker)
55 );
56
57 flush_dcache_range((u32)parent, (u32)parent + 4);
58 flush_icache_range((u32)parent, (u32)parent + 4);
59
60 if (unlikely(faulted)) {
61 ftrace_graph_stop();
62 WARN_ON(1);
63 return;
64 }
65
66 err = ftrace_push_return_trace(old, self_addr, &trace.depth, 0, NULL);
67 if (err == -EBUSY) {
68 *parent = old;
69 return;
70 }
71
72 trace.func = self_addr;
73 /* Only trace if the calling function expects to */
74 if (!ftrace_graph_entry(&trace)) {
75 current->curr_ret_stack--;
76 *parent = old;
77 }
78}
79#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
80
81#ifdef CONFIG_DYNAMIC_FTRACE
82/* save value to addr - it is save to do it in asm */
83static int ftrace_modify_code(unsigned long addr, unsigned int value)
84{
85 int faulted = 0;
86
87 __asm__ __volatile__(" 1: swi %2, %1, 0;" \
88 " addik %0, r0, 0;" \
89 "2:" \
90 " .section .fixup, \"ax\";" \
91 "3: brid 2b;" \
92 " addik %0, r0, 1;" \
93 " .previous;" \
94 " .section __ex_table,\"a\";" \
95 " .word 1b,3b;" \
96 " .previous;" \
97 : "=r" (faulted)
98 : "r" (addr), "r" (value)
99 );
100
101 if (unlikely(faulted))
102 return -EFAULT;
103
104 flush_dcache_range(addr, addr + 4);
105 flush_icache_range(addr, addr + 4);
106
107 return 0;
108}
109
110#define MICROBLAZE_NOP 0x80000000
111#define MICROBLAZE_BRI 0xb800000C
112
113static unsigned int recorded; /* if save was or not */
114static unsigned int imm; /* saving whole imm instruction */
115
116/* There are two approaches howto solve ftrace_make nop function - look below */
117#undef USE_FTRACE_NOP
118
119#ifdef USE_FTRACE_NOP
120static unsigned int bralid; /* saving whole bralid instruction */
121#endif
122
123int ftrace_make_nop(struct module *mod,
124 struct dyn_ftrace *rec, unsigned long addr)
125{
126 /* we have this part of code which we are working with
127 * b000c000 imm -16384
128 * b9fc8e30 bralid r15, -29136 // c0008e30 <_mcount>
129 * 80000000 or r0, r0, r0
130 *
131 * The first solution (!USE_FTRACE_NOP-could be called branch solution)
132 * b000c000 bri 12 (0xC - jump to any other instruction)
133 * b9fc8e30 bralid r15, -29136 // c0008e30 <_mcount>
134 * 80000000 or r0, r0, r0
135 * any other instruction
136 *
137 * The second solution (USE_FTRACE_NOP) - no jump just nops
138 * 80000000 or r0, r0, r0
139 * 80000000 or r0, r0, r0
140 * 80000000 or r0, r0, r0
141 */
142 int ret = 0;
143
144 if (recorded == 0) {
145 recorded = 1;
146 imm = *(unsigned int *)rec->ip;
147 pr_debug("%s: imm:0x%x\n", __func__, imm);
148#ifdef USE_FTRACE_NOP
149 bralid = *(unsigned int *)(rec->ip + 4);
150 pr_debug("%s: bralid 0x%x\n", __func__, bralid);
151#endif /* USE_FTRACE_NOP */
152 }
153
154#ifdef USE_FTRACE_NOP
155 ret = ftrace_modify_code(rec->ip, MICROBLAZE_NOP);
156 ret += ftrace_modify_code(rec->ip + 4, MICROBLAZE_NOP);
157#else /* USE_FTRACE_NOP */
158 ret = ftrace_modify_code(rec->ip, MICROBLAZE_BRI);
159#endif /* USE_FTRACE_NOP */
160 return ret;
161}
162
163/* I believe that first is called ftrace_make_nop before this function */
164int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
165{
166 int ret;
167 pr_debug("%s: addr:0x%x, rec->ip: 0x%x, imm:0x%x\n",
168 __func__, (unsigned int)addr, (unsigned int)rec->ip, imm);
169 ret = ftrace_modify_code(rec->ip, imm);
170#ifdef USE_FTRACE_NOP
171 pr_debug("%s: bralid:0x%x\n", __func__, bralid);
172 ret += ftrace_modify_code(rec->ip + 4, bralid);
173#endif /* USE_FTRACE_NOP */
174 return ret;
175}
176
177int __init ftrace_dyn_arch_init(void)
178{
179 return 0;
180}
181
182int ftrace_update_ftrace_func(ftrace_func_t func)
183{
184 unsigned long ip = (unsigned long)(&ftrace_call);
185 unsigned int upper = (unsigned int)func;
186 unsigned int lower = (unsigned int)func;
187 int ret = 0;
188
189 /* create proper saving to ftrace_call poll */
190 upper = 0xb0000000 + (upper >> 16); /* imm func_upper */
191 lower = 0x32800000 + (lower & 0xFFFF); /* addik r20, r0, func_lower */
192
193 pr_debug("%s: func=0x%x, ip=0x%x, upper=0x%x, lower=0x%x\n",
194 __func__, (unsigned int)func, (unsigned int)ip, upper, lower);
195
196 /* save upper and lower code */
197 ret = ftrace_modify_code(ip, upper);
198 ret += ftrace_modify_code(ip + 4, lower);
199
200 /* We just need to replace the rtsd r15, 8 with NOP */
201 ret += ftrace_modify_code((unsigned long)&ftrace_caller,
202 MICROBLAZE_NOP);
203
204 return ret;
205}
206
207#ifdef CONFIG_FUNCTION_GRAPH_TRACER
208unsigned int old_jump; /* saving place for jump instruction */
209
210int ftrace_enable_ftrace_graph_caller(void)
211{
212 unsigned int ret;
213 unsigned long ip = (unsigned long)(&ftrace_call_graph);
214
215 old_jump = *(unsigned int *)ip; /* save jump over instruction */
216 ret = ftrace_modify_code(ip, MICROBLAZE_NOP);
217
218 pr_debug("%s: Replace instruction: 0x%x\n", __func__, old_jump);
219 return ret;
220}
221
222int ftrace_disable_ftrace_graph_caller(void)
223{
224 unsigned int ret;
225 unsigned long ip = (unsigned long)(&ftrace_call_graph);
226
227 ret = ftrace_modify_code(ip, old_jump);
228
229 pr_debug("%s\n", __func__);
230 return ret;
231}
232#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
233#endif /* CONFIG_DYNAMIC_FTRACE */
1/*
2 * Ftrace support for Microblaze.
3 *
4 * Copyright (C) 2009 Michal Simek <monstr@monstr.eu>
5 * Copyright (C) 2009 PetaLogix
6 *
7 * Based on MIPS and PowerPC ftrace code
8 *
9 * This file is subject to the terms and conditions of the GNU General Public
10 * License. See the file "COPYING" in the main directory of this archive
11 * for more details.
12 */
13
14#include <asm/cacheflush.h>
15#include <linux/ftrace.h>
16
17#ifdef CONFIG_FUNCTION_GRAPH_TRACER
18/*
19 * Hook the return address and push it in the stack of return addrs
20 * in current thread info.
21 */
22void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
23{
24 unsigned long old;
25 int faulted;
26 unsigned long return_hooker = (unsigned long)
27 &return_to_handler;
28
29 if (unlikely(ftrace_graph_is_dead()))
30 return;
31
32 if (unlikely(atomic_read(¤t->tracing_graph_pause)))
33 return;
34
35 /*
36 * Protect against fault, even if it shouldn't
37 * happen. This tool is too much intrusive to
38 * ignore such a protection.
39 */
40 asm volatile(" 1: lwi %0, %2, 0;" \
41 "2: swi %3, %2, 0;" \
42 " addik %1, r0, 0;" \
43 "3:" \
44 " .section .fixup, \"ax\";" \
45 "4: brid 3b;" \
46 " addik %1, r0, 1;" \
47 " .previous;" \
48 " .section __ex_table,\"a\";" \
49 " .word 1b,4b;" \
50 " .word 2b,4b;" \
51 " .previous;" \
52 : "=&r" (old), "=r" (faulted)
53 : "r" (parent), "r" (return_hooker)
54 );
55
56 flush_dcache_range((u32)parent, (u32)parent + 4);
57 flush_icache_range((u32)parent, (u32)parent + 4);
58
59 if (unlikely(faulted)) {
60 ftrace_graph_stop();
61 WARN_ON(1);
62 return;
63 }
64
65 if (function_graph_enter(old, self_addr, 0, NULL))
66 *parent = old;
67}
68#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
69
70#ifdef CONFIG_DYNAMIC_FTRACE
71/* save value to addr - it is save to do it in asm */
72static int ftrace_modify_code(unsigned long addr, unsigned int value)
73{
74 int faulted = 0;
75
76 __asm__ __volatile__(" 1: swi %2, %1, 0;" \
77 " addik %0, r0, 0;" \
78 "2:" \
79 " .section .fixup, \"ax\";" \
80 "3: brid 2b;" \
81 " addik %0, r0, 1;" \
82 " .previous;" \
83 " .section __ex_table,\"a\";" \
84 " .word 1b,3b;" \
85 " .previous;" \
86 : "=r" (faulted)
87 : "r" (addr), "r" (value)
88 );
89
90 if (unlikely(faulted))
91 return -EFAULT;
92
93 flush_dcache_range(addr, addr + 4);
94 flush_icache_range(addr, addr + 4);
95
96 return 0;
97}
98
99#define MICROBLAZE_NOP 0x80000000
100#define MICROBLAZE_BRI 0xb800000C
101
102static unsigned int recorded; /* if save was or not */
103static unsigned int imm; /* saving whole imm instruction */
104
105/* There are two approaches howto solve ftrace_make nop function - look below */
106#undef USE_FTRACE_NOP
107
108#ifdef USE_FTRACE_NOP
109static unsigned int bralid; /* saving whole bralid instruction */
110#endif
111
112int ftrace_make_nop(struct module *mod,
113 struct dyn_ftrace *rec, unsigned long addr)
114{
115 /* we have this part of code which we are working with
116 * b000c000 imm -16384
117 * b9fc8e30 bralid r15, -29136 // c0008e30 <_mcount>
118 * 80000000 or r0, r0, r0
119 *
120 * The first solution (!USE_FTRACE_NOP-could be called branch solution)
121 * b000c000 bri 12 (0xC - jump to any other instruction)
122 * b9fc8e30 bralid r15, -29136 // c0008e30 <_mcount>
123 * 80000000 or r0, r0, r0
124 * any other instruction
125 *
126 * The second solution (USE_FTRACE_NOP) - no jump just nops
127 * 80000000 or r0, r0, r0
128 * 80000000 or r0, r0, r0
129 * 80000000 or r0, r0, r0
130 */
131 int ret = 0;
132
133 if (recorded == 0) {
134 recorded = 1;
135 imm = *(unsigned int *)rec->ip;
136 pr_debug("%s: imm:0x%x\n", __func__, imm);
137#ifdef USE_FTRACE_NOP
138 bralid = *(unsigned int *)(rec->ip + 4);
139 pr_debug("%s: bralid 0x%x\n", __func__, bralid);
140#endif /* USE_FTRACE_NOP */
141 }
142
143#ifdef USE_FTRACE_NOP
144 ret = ftrace_modify_code(rec->ip, MICROBLAZE_NOP);
145 ret += ftrace_modify_code(rec->ip + 4, MICROBLAZE_NOP);
146#else /* USE_FTRACE_NOP */
147 ret = ftrace_modify_code(rec->ip, MICROBLAZE_BRI);
148#endif /* USE_FTRACE_NOP */
149 return ret;
150}
151
152/* I believe that first is called ftrace_make_nop before this function */
153int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
154{
155 int ret;
156 pr_debug("%s: addr:0x%x, rec->ip: 0x%x, imm:0x%x\n",
157 __func__, (unsigned int)addr, (unsigned int)rec->ip, imm);
158 ret = ftrace_modify_code(rec->ip, imm);
159#ifdef USE_FTRACE_NOP
160 pr_debug("%s: bralid:0x%x\n", __func__, bralid);
161 ret += ftrace_modify_code(rec->ip + 4, bralid);
162#endif /* USE_FTRACE_NOP */
163 return ret;
164}
165
166int __init ftrace_dyn_arch_init(void)
167{
168 return 0;
169}
170
171int ftrace_update_ftrace_func(ftrace_func_t func)
172{
173 unsigned long ip = (unsigned long)(&ftrace_call);
174 unsigned int upper = (unsigned int)func;
175 unsigned int lower = (unsigned int)func;
176 int ret = 0;
177
178 /* create proper saving to ftrace_call poll */
179 upper = 0xb0000000 + (upper >> 16); /* imm func_upper */
180 lower = 0x32800000 + (lower & 0xFFFF); /* addik r20, r0, func_lower */
181
182 pr_debug("%s: func=0x%x, ip=0x%x, upper=0x%x, lower=0x%x\n",
183 __func__, (unsigned int)func, (unsigned int)ip, upper, lower);
184
185 /* save upper and lower code */
186 ret = ftrace_modify_code(ip, upper);
187 ret += ftrace_modify_code(ip + 4, lower);
188
189 /* We just need to replace the rtsd r15, 8 with NOP */
190 ret += ftrace_modify_code((unsigned long)&ftrace_caller,
191 MICROBLAZE_NOP);
192
193 return ret;
194}
195
196#ifdef CONFIG_FUNCTION_GRAPH_TRACER
197unsigned int old_jump; /* saving place for jump instruction */
198
199int ftrace_enable_ftrace_graph_caller(void)
200{
201 unsigned int ret;
202 unsigned long ip = (unsigned long)(&ftrace_call_graph);
203
204 old_jump = *(unsigned int *)ip; /* save jump over instruction */
205 ret = ftrace_modify_code(ip, MICROBLAZE_NOP);
206
207 pr_debug("%s: Replace instruction: 0x%x\n", __func__, old_jump);
208 return ret;
209}
210
211int ftrace_disable_ftrace_graph_caller(void)
212{
213 unsigned int ret;
214 unsigned long ip = (unsigned long)(&ftrace_call_graph);
215
216 ret = ftrace_modify_code(ip, old_jump);
217
218 pr_debug("%s\n", __func__);
219 return ret;
220}
221#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
222#endif /* CONFIG_DYNAMIC_FTRACE */