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7d241ff0 MS |
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 | ||
a0d3e665 MS |
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 | */ | |
22 | void 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 | ||
e1dc5007 SRRH |
30 | if (unlikely(ftrace_graph_is_dead())) |
31 | return; | |
32 | ||
a0d3e665 MS |
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 | */ | |
6bd55f0b MS |
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;" \ | |
a0d3e665 MS |
53 | : "=&r" (old), "=r" (faulted) |
54 | : "r" (parent), "r" (return_hooker) | |
55 | ); | |
56 | ||
9e1491de MS |
57 | flush_dcache_range((u32)parent, (u32)parent + 4); |
58 | flush_icache_range((u32)parent, (u32)parent + 4); | |
59 | ||
a0d3e665 MS |
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); | |
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 | ||
7d241ff0 MS |
81 | #ifdef CONFIG_DYNAMIC_FTRACE |
82 | /* save value to addr - it is save to do it in asm */ | |
83 | static int ftrace_modify_code(unsigned long addr, unsigned int value) | |
84 | { | |
85 | int faulted = 0; | |
86 | ||
6bd55f0b MS |
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;" \ | |
7d241ff0 MS |
97 | : "=r" (faulted) |
98 | : "r" (addr), "r" (value) | |
99 | ); | |
100 | ||
101 | if (unlikely(faulted)) | |
102 | return -EFAULT; | |
103 | ||
9e1491de MS |
104 | flush_dcache_range(addr, addr + 4); |
105 | flush_icache_range(addr, addr + 4); | |
106 | ||
7d241ff0 MS |
107 | return 0; |
108 | } | |
109 | ||
110 | #define MICROBLAZE_NOP 0x80000000 | |
111 | #define MICROBLAZE_BRI 0xb800000C | |
112 | ||
113 | static unsigned int recorded; /* if save was or not */ | |
114 | static 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 | |
120 | static unsigned int bralid; /* saving whole bralid instruction */ | |
121 | #endif | |
122 | ||
123 | int 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 | ||
7d241ff0 MS |
163 | /* I believe that first is called ftrace_make_nop before this function */ |
164 | int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) | |
165 | { | |
166 | int ret; | |
7d241ff0 MS |
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 | ||
3a36cb11 | 177 | int __init ftrace_dyn_arch_init(void) |
7d241ff0 | 178 | { |
7d241ff0 MS |
179 | return 0; |
180 | } | |
181 | ||
182 | int 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 | ||
d2bf98e6 SM |
200 | /* We just need to replace the rtsd r15, 8 with NOP */ |
201 | ret += ftrace_modify_code((unsigned long)&ftrace_caller, | |
202 | MICROBLAZE_NOP); | |
7d241ff0 | 203 | |
7d241ff0 MS |
204 | return ret; |
205 | } | |
206 | ||
4f911b0d MS |
207 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
208 | unsigned int old_jump; /* saving place for jump instruction */ | |
209 | ||
210 | int 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); | |
4f911b0d MS |
217 | |
218 | pr_debug("%s: Replace instruction: 0x%x\n", __func__, old_jump); | |
219 | return ret; | |
220 | } | |
221 | ||
222 | int 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); | |
4f911b0d MS |
228 | |
229 | pr_debug("%s\n", __func__); | |
230 | return ret; | |
231 | } | |
232 | #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ | |
7d241ff0 | 233 | #endif /* CONFIG_DYNAMIC_FTRACE */ |