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a61fd5e3 TL |
1 | /* |
2 | * Copyright 2012 Tilera Corporation. All Rights Reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation, version 2. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but | |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or | |
11 | * NON INFRINGEMENT. See the GNU General Public License for | |
12 | * more details. | |
13 | * | |
14 | * TILE-Gx specific ftrace support | |
15 | */ | |
16 | ||
17 | #include <linux/ftrace.h> | |
18 | #include <linux/uaccess.h> | |
19 | ||
20 | #include <asm/cacheflush.h> | |
21 | #include <asm/ftrace.h> | |
22 | #include <asm/sections.h> | |
23 | ||
24 | #include <arch/opcode.h> | |
25 | ||
26 | #ifdef CONFIG_DYNAMIC_FTRACE | |
27 | ||
28 | static inline tilegx_bundle_bits NOP(void) | |
29 | { | |
30 | return create_UnaryOpcodeExtension_X0(FNOP_UNARY_OPCODE_X0) | | |
31 | create_RRROpcodeExtension_X0(UNARY_RRR_0_OPCODE_X0) | | |
32 | create_Opcode_X0(RRR_0_OPCODE_X0) | | |
33 | create_UnaryOpcodeExtension_X1(NOP_UNARY_OPCODE_X1) | | |
34 | create_RRROpcodeExtension_X1(UNARY_RRR_0_OPCODE_X1) | | |
35 | create_Opcode_X1(RRR_0_OPCODE_X1); | |
36 | } | |
37 | ||
38 | static int machine_stopped __read_mostly; | |
39 | ||
40 | int ftrace_arch_code_modify_prepare(void) | |
41 | { | |
42 | machine_stopped = 1; | |
43 | return 0; | |
44 | } | |
45 | ||
46 | int ftrace_arch_code_modify_post_process(void) | |
47 | { | |
48 | flush_icache_range(0, CHIP_L1I_CACHE_SIZE()); | |
49 | machine_stopped = 0; | |
50 | return 0; | |
51 | } | |
52 | ||
53 | /* | |
54 | * Put { move r10, lr; jal ftrace_caller } in a bundle, this lets dynamic | |
55 | * tracer just add one cycle overhead to every kernel function when disabled. | |
56 | */ | |
57 | static unsigned long ftrace_gen_branch(unsigned long pc, unsigned long addr, | |
58 | bool link) | |
59 | { | |
60 | tilegx_bundle_bits opcode_x0, opcode_x1; | |
61 | long pcrel_by_instr = (addr - pc) >> TILEGX_LOG2_BUNDLE_SIZE_IN_BYTES; | |
62 | ||
63 | if (link) { | |
64 | /* opcode: jal addr */ | |
65 | opcode_x1 = | |
66 | create_Opcode_X1(JUMP_OPCODE_X1) | | |
67 | create_JumpOpcodeExtension_X1(JAL_JUMP_OPCODE_X1) | | |
68 | create_JumpOff_X1(pcrel_by_instr); | |
69 | } else { | |
70 | /* opcode: j addr */ | |
71 | opcode_x1 = | |
72 | create_Opcode_X1(JUMP_OPCODE_X1) | | |
73 | create_JumpOpcodeExtension_X1(J_JUMP_OPCODE_X1) | | |
74 | create_JumpOff_X1(pcrel_by_instr); | |
75 | } | |
76 | ||
437d3e12 TL |
77 | /* |
78 | * Also put { move r10, lr; jal ftrace_stub } in a bundle, which | |
79 | * is used to replace the instruction in address ftrace_call. | |
80 | */ | |
81 | if (addr == FTRACE_ADDR || addr == (unsigned long)ftrace_stub) { | |
a61fd5e3 TL |
82 | /* opcode: or r10, lr, zero */ |
83 | opcode_x0 = | |
84 | create_Dest_X0(10) | | |
85 | create_SrcA_X0(TREG_LR) | | |
86 | create_SrcB_X0(TREG_ZERO) | | |
87 | create_RRROpcodeExtension_X0(OR_RRR_0_OPCODE_X0) | | |
88 | create_Opcode_X0(RRR_0_OPCODE_X0); | |
89 | } else { | |
90 | /* opcode: fnop */ | |
91 | opcode_x0 = | |
92 | create_UnaryOpcodeExtension_X0(FNOP_UNARY_OPCODE_X0) | | |
93 | create_RRROpcodeExtension_X0(UNARY_RRR_0_OPCODE_X0) | | |
94 | create_Opcode_X0(RRR_0_OPCODE_X0); | |
95 | } | |
96 | ||
97 | return opcode_x1 | opcode_x0; | |
98 | } | |
99 | ||
100 | static unsigned long ftrace_nop_replace(struct dyn_ftrace *rec) | |
101 | { | |
102 | return NOP(); | |
103 | } | |
104 | ||
105 | static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr) | |
106 | { | |
107 | return ftrace_gen_branch(pc, addr, true); | |
108 | } | |
109 | ||
110 | static int ftrace_modify_code(unsigned long pc, unsigned long old, | |
111 | unsigned long new) | |
112 | { | |
113 | unsigned long pc_wr; | |
114 | ||
115 | /* Check if the address is in kernel text space and module space. */ | |
116 | if (!kernel_text_address(pc)) | |
117 | return -EINVAL; | |
118 | ||
119 | /* Operate on writable kernel text mapping. */ | |
f419e6f6 | 120 | pc_wr = ktext_writable_addr(pc); |
a61fd5e3 TL |
121 | |
122 | if (probe_kernel_write((void *)pc_wr, &new, MCOUNT_INSN_SIZE)) | |
123 | return -EPERM; | |
124 | ||
125 | smp_wmb(); | |
126 | ||
127 | if (!machine_stopped && num_online_cpus() > 1) | |
128 | flush_icache_range(pc, pc + MCOUNT_INSN_SIZE); | |
129 | ||
130 | return 0; | |
131 | } | |
132 | ||
133 | int ftrace_update_ftrace_func(ftrace_func_t func) | |
134 | { | |
135 | unsigned long pc, old; | |
136 | unsigned long new; | |
137 | int ret; | |
138 | ||
139 | pc = (unsigned long)&ftrace_call; | |
140 | memcpy(&old, &ftrace_call, MCOUNT_INSN_SIZE); | |
141 | new = ftrace_call_replace(pc, (unsigned long)func); | |
142 | ||
143 | ret = ftrace_modify_code(pc, old, new); | |
144 | ||
145 | return ret; | |
146 | } | |
147 | ||
148 | int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) | |
149 | { | |
150 | unsigned long new, old; | |
151 | unsigned long ip = rec->ip; | |
152 | ||
153 | old = ftrace_nop_replace(rec); | |
154 | new = ftrace_call_replace(ip, addr); | |
155 | ||
156 | return ftrace_modify_code(rec->ip, old, new); | |
157 | } | |
158 | ||
159 | int ftrace_make_nop(struct module *mod, | |
160 | struct dyn_ftrace *rec, unsigned long addr) | |
161 | { | |
162 | unsigned long ip = rec->ip; | |
163 | unsigned long old; | |
164 | unsigned long new; | |
165 | int ret; | |
166 | ||
167 | old = ftrace_call_replace(ip, addr); | |
168 | new = ftrace_nop_replace(rec); | |
169 | ret = ftrace_modify_code(ip, old, new); | |
170 | ||
171 | return ret; | |
172 | } | |
173 | ||
3a36cb11 | 174 | int __init ftrace_dyn_arch_init(void) |
a61fd5e3 | 175 | { |
a61fd5e3 TL |
176 | return 0; |
177 | } | |
178 | #endif /* CONFIG_DYNAMIC_FTRACE */ | |
179 | ||
180 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER | |
181 | void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, | |
182 | unsigned long frame_pointer) | |
183 | { | |
184 | unsigned long return_hooker = (unsigned long) &return_to_handler; | |
185 | struct ftrace_graph_ent trace; | |
186 | unsigned long old; | |
187 | int err; | |
188 | ||
189 | if (unlikely(atomic_read(¤t->tracing_graph_pause))) | |
190 | return; | |
191 | ||
192 | old = *parent; | |
193 | *parent = return_hooker; | |
194 | ||
195 | err = ftrace_push_return_trace(old, self_addr, &trace.depth, | |
196 | frame_pointer); | |
197 | if (err == -EBUSY) { | |
198 | *parent = old; | |
199 | return; | |
200 | } | |
201 | ||
202 | trace.func = self_addr; | |
203 | ||
204 | /* Only trace if the calling function expects to */ | |
205 | if (!ftrace_graph_entry(&trace)) { | |
206 | current->curr_ret_stack--; | |
207 | *parent = old; | |
208 | } | |
209 | } | |
210 | ||
211 | #ifdef CONFIG_DYNAMIC_FTRACE | |
212 | extern unsigned long ftrace_graph_call; | |
213 | ||
214 | static int __ftrace_modify_caller(unsigned long *callsite, | |
215 | void (*func) (void), bool enable) | |
216 | { | |
217 | unsigned long caller_fn = (unsigned long) func; | |
218 | unsigned long pc = (unsigned long) callsite; | |
219 | unsigned long branch = ftrace_gen_branch(pc, caller_fn, false); | |
220 | unsigned long nop = NOP(); | |
221 | unsigned long old = enable ? nop : branch; | |
222 | unsigned long new = enable ? branch : nop; | |
223 | ||
224 | return ftrace_modify_code(pc, old, new); | |
225 | } | |
226 | ||
227 | static int ftrace_modify_graph_caller(bool enable) | |
228 | { | |
229 | int ret; | |
230 | ||
231 | ret = __ftrace_modify_caller(&ftrace_graph_call, | |
232 | ftrace_graph_caller, | |
233 | enable); | |
234 | ||
235 | return ret; | |
236 | } | |
237 | ||
238 | int ftrace_enable_ftrace_graph_caller(void) | |
239 | { | |
240 | return ftrace_modify_graph_caller(true); | |
241 | } | |
242 | ||
243 | int ftrace_disable_ftrace_graph_caller(void) | |
244 | { | |
245 | return ftrace_modify_graph_caller(false); | |
246 | } | |
247 | #endif /* CONFIG_DYNAMIC_FTRACE */ | |
248 | #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |