Commit | Line | Data |
---|---|---|
4e491d14 SR |
1 | /* |
2 | * Code for replacing ftrace calls with jumps. | |
3 | * | |
4 | * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> | |
5 | * | |
6 | * Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box. | |
7 | * | |
6794c782 SR |
8 | * Added function graph tracer code, taken from x86 that was written |
9 | * by Frederic Weisbecker, and ported to PPC by Steven Rostedt. | |
10 | * | |
4e491d14 SR |
11 | */ |
12 | ||
13 | #include <linux/spinlock.h> | |
14 | #include <linux/hardirq.h> | |
e4486fe3 | 15 | #include <linux/uaccess.h> |
f48cb8b4 | 16 | #include <linux/module.h> |
4e491d14 SR |
17 | #include <linux/ftrace.h> |
18 | #include <linux/percpu.h> | |
19 | #include <linux/init.h> | |
20 | #include <linux/list.h> | |
21 | ||
22 | #include <asm/cacheflush.h> | |
f48cb8b4 | 23 | #include <asm/code-patching.h> |
395a59d0 | 24 | #include <asm/ftrace.h> |
02424d89 | 25 | #include <asm/syscall.h> |
4e491d14 | 26 | |
4e491d14 | 27 | |
6794c782 | 28 | #ifdef CONFIG_DYNAMIC_FTRACE |
b54dcfe1 | 29 | static unsigned int |
46542888 | 30 | ftrace_call_replace(unsigned long ip, unsigned long addr, int link) |
4e491d14 | 31 | { |
b54dcfe1 | 32 | unsigned int op; |
4e491d14 | 33 | |
4a9e3f8e | 34 | addr = ppc_function_entry((void *)addr); |
4e491d14 | 35 | |
46542888 | 36 | /* if (link) set op to 'bl' else 'b' */ |
bb9b9035 | 37 | op = create_branch((unsigned int *)ip, addr, link ? 1 : 0); |
4e491d14 | 38 | |
b54dcfe1 | 39 | return op; |
4e491d14 SR |
40 | } |
41 | ||
8fd6e5a8 | 42 | static int |
b54dcfe1 | 43 | ftrace_modify_code(unsigned long ip, unsigned int old, unsigned int new) |
4e491d14 | 44 | { |
b54dcfe1 | 45 | unsigned int replaced; |
4e491d14 | 46 | |
4e491d14 SR |
47 | /* |
48 | * Note: Due to modules and __init, code can | |
49 | * disappear and change, we need to protect against faulting | |
e4486fe3 SR |
50 | * as well as code changing. We do this by using the |
51 | * probe_kernel_* functions. | |
4e491d14 SR |
52 | * |
53 | * No real locking needed, this code is run through | |
e4486fe3 | 54 | * kstop_machine, or before SMP starts. |
4e491d14 | 55 | */ |
e4486fe3 SR |
56 | |
57 | /* read the text we want to modify */ | |
b54dcfe1 | 58 | if (probe_kernel_read(&replaced, (void *)ip, MCOUNT_INSN_SIZE)) |
e4486fe3 SR |
59 | return -EFAULT; |
60 | ||
61 | /* Make sure it is what we expect it to be */ | |
b54dcfe1 | 62 | if (replaced != old) |
e4486fe3 SR |
63 | return -EINVAL; |
64 | ||
65 | /* replace the text with the new text */ | |
b54dcfe1 | 66 | if (probe_kernel_write((void *)ip, &new, MCOUNT_INSN_SIZE)) |
e4486fe3 SR |
67 | return -EPERM; |
68 | ||
69 | flush_icache_range(ip, ip + 8); | |
70 | ||
71 | return 0; | |
4e491d14 SR |
72 | } |
73 | ||
f48cb8b4 SR |
74 | /* |
75 | * Helper functions that are the same for both PPC64 and PPC32. | |
76 | */ | |
8fd6e5a8 SR |
77 | static int test_24bit_addr(unsigned long ip, unsigned long addr) |
78 | { | |
8fd6e5a8 | 79 | |
0029ff87 SR |
80 | /* use the create_branch to verify that this offset can be branched */ |
81 | return create_branch((unsigned int *)ip, addr, 0); | |
8fd6e5a8 SR |
82 | } |
83 | ||
17be5b3d SR |
84 | #ifdef CONFIG_MODULES |
85 | ||
f48cb8b4 SR |
86 | static int is_bl_op(unsigned int op) |
87 | { | |
88 | return (op & 0xfc000003) == 0x48000001; | |
89 | } | |
90 | ||
f48cb8b4 SR |
91 | static unsigned long find_bl_target(unsigned long ip, unsigned int op) |
92 | { | |
93 | static int offset; | |
94 | ||
95 | offset = (op & 0x03fffffc); | |
96 | /* make it signed */ | |
97 | if (offset & 0x02000000) | |
98 | offset |= 0xfe000000; | |
99 | ||
100 | return ip + (long)offset; | |
101 | } | |
102 | ||
f48cb8b4 SR |
103 | #ifdef CONFIG_PPC64 |
104 | static int | |
105 | __ftrace_make_nop(struct module *mod, | |
106 | struct dyn_ftrace *rec, unsigned long addr) | |
107 | { | |
d9af12b7 SR |
108 | unsigned int op; |
109 | unsigned int jmp[5]; | |
110 | unsigned long ptr; | |
f48cb8b4 SR |
111 | unsigned long ip = rec->ip; |
112 | unsigned long tramp; | |
113 | int offset; | |
114 | ||
115 | /* read where this goes */ | |
d9af12b7 | 116 | if (probe_kernel_read(&op, (void *)ip, sizeof(int))) |
f48cb8b4 SR |
117 | return -EFAULT; |
118 | ||
119 | /* Make sure that that this is still a 24bit jump */ | |
d9af12b7 SR |
120 | if (!is_bl_op(op)) { |
121 | printk(KERN_ERR "Not expected bl: opcode is %x\n", op); | |
f48cb8b4 SR |
122 | return -EINVAL; |
123 | } | |
124 | ||
125 | /* lets find where the pointer goes */ | |
d9af12b7 | 126 | tramp = find_bl_target(ip, op); |
f48cb8b4 SR |
127 | |
128 | /* | |
129 | * On PPC64 the trampoline looks like: | |
130 | * 0x3d, 0x82, 0x00, 0x00, addis r12,r2, <high> | |
131 | * 0x39, 0x8c, 0x00, 0x00, addi r12,r12, <low> | |
132 | * Where the bytes 2,3,6 and 7 make up the 32bit offset | |
133 | * to the TOC that holds the pointer. | |
134 | * to jump to. | |
135 | * 0xf8, 0x41, 0x00, 0x28, std r2,40(r1) | |
136 | * 0xe9, 0x6c, 0x00, 0x20, ld r11,32(r12) | |
137 | * The actually address is 32 bytes from the offset | |
138 | * into the TOC. | |
139 | * 0xe8, 0x4c, 0x00, 0x28, ld r2,40(r12) | |
140 | */ | |
141 | ||
021376a3 | 142 | pr_devel("ip:%lx jumps to %lx r2: %lx", ip, tramp, mod->arch.toc); |
f48cb8b4 SR |
143 | |
144 | /* Find where the trampoline jumps to */ | |
d9af12b7 | 145 | if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) { |
f48cb8b4 SR |
146 | printk(KERN_ERR "Failed to read %lx\n", tramp); |
147 | return -EFAULT; | |
148 | } | |
149 | ||
021376a3 | 150 | pr_devel(" %08x %08x", jmp[0], jmp[1]); |
d9af12b7 SR |
151 | |
152 | /* verify that this is what we expect it to be */ | |
153 | if (((jmp[0] & 0xffff0000) != 0x3d820000) || | |
154 | ((jmp[1] & 0xffff0000) != 0x398c0000) || | |
155 | (jmp[2] != 0xf8410028) || | |
156 | (jmp[3] != 0xe96c0020) || | |
157 | (jmp[4] != 0xe84c0028)) { | |
158 | printk(KERN_ERR "Not a trampoline\n"); | |
159 | return -EINVAL; | |
160 | } | |
f48cb8b4 | 161 | |
f25f9074 SR |
162 | /* The bottom half is signed extended */ |
163 | offset = ((unsigned)((unsigned short)jmp[0]) << 16) + | |
164 | (int)((short)jmp[1]); | |
f48cb8b4 | 165 | |
021376a3 | 166 | pr_devel(" %x ", offset); |
f48cb8b4 SR |
167 | |
168 | /* get the address this jumps too */ | |
169 | tramp = mod->arch.toc + offset + 32; | |
021376a3 | 170 | pr_devel("toc: %lx", tramp); |
f48cb8b4 SR |
171 | |
172 | if (probe_kernel_read(jmp, (void *)tramp, 8)) { | |
173 | printk(KERN_ERR "Failed to read %lx\n", tramp); | |
174 | return -EFAULT; | |
175 | } | |
176 | ||
021376a3 | 177 | pr_devel(" %08x %08x\n", jmp[0], jmp[1]); |
d9af12b7 SR |
178 | |
179 | ptr = ((unsigned long)jmp[0] << 32) + jmp[1]; | |
f48cb8b4 SR |
180 | |
181 | /* This should match what was called */ | |
4a9e3f8e | 182 | if (ptr != ppc_function_entry((void *)addr)) { |
d9af12b7 | 183 | printk(KERN_ERR "addr does not match %lx\n", ptr); |
f48cb8b4 SR |
184 | return -EINVAL; |
185 | } | |
186 | ||
187 | /* | |
188 | * We want to nop the line, but the next line is | |
189 | * 0xe8, 0x41, 0x00, 0x28 ld r2,40(r1) | |
190 | * This needs to be turned to a nop too. | |
191 | */ | |
d9af12b7 | 192 | if (probe_kernel_read(&op, (void *)(ip+4), MCOUNT_INSN_SIZE)) |
f48cb8b4 SR |
193 | return -EFAULT; |
194 | ||
d9af12b7 SR |
195 | if (op != 0xe8410028) { |
196 | printk(KERN_ERR "Next line is not ld! (%08x)\n", op); | |
f48cb8b4 SR |
197 | return -EINVAL; |
198 | } | |
199 | ||
200 | /* | |
201 | * Milton Miller pointed out that we can not blindly do nops. | |
202 | * If a task was preempted when calling a trace function, | |
203 | * the nops will remove the way to restore the TOC in r2 | |
204 | * and the r2 TOC will get corrupted. | |
205 | */ | |
206 | ||
207 | /* | |
208 | * Replace: | |
209 | * bl <tramp> <==== will be replaced with "b 1f" | |
210 | * ld r2,40(r1) | |
211 | * 1: | |
212 | */ | |
d9af12b7 | 213 | op = 0x48000008; /* b +8 */ |
f48cb8b4 | 214 | |
d9af12b7 | 215 | if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE)) |
f48cb8b4 SR |
216 | return -EPERM; |
217 | ||
ec682cef SR |
218 | |
219 | flush_icache_range(ip, ip + 8); | |
220 | ||
f48cb8b4 SR |
221 | return 0; |
222 | } | |
223 | ||
224 | #else /* !PPC64 */ | |
225 | static int | |
226 | __ftrace_make_nop(struct module *mod, | |
227 | struct dyn_ftrace *rec, unsigned long addr) | |
228 | { | |
d9af12b7 SR |
229 | unsigned int op; |
230 | unsigned int jmp[4]; | |
7cc45e64 SR |
231 | unsigned long ip = rec->ip; |
232 | unsigned long tramp; | |
7cc45e64 | 233 | |
d9af12b7 | 234 | if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE)) |
7cc45e64 SR |
235 | return -EFAULT; |
236 | ||
237 | /* Make sure that that this is still a 24bit jump */ | |
d9af12b7 SR |
238 | if (!is_bl_op(op)) { |
239 | printk(KERN_ERR "Not expected bl: opcode is %x\n", op); | |
7cc45e64 SR |
240 | return -EINVAL; |
241 | } | |
242 | ||
243 | /* lets find where the pointer goes */ | |
d9af12b7 | 244 | tramp = find_bl_target(ip, op); |
7cc45e64 SR |
245 | |
246 | /* | |
247 | * On PPC32 the trampoline looks like: | |
d9af12b7 SR |
248 | * 0x3d, 0x60, 0x00, 0x00 lis r11,sym@ha |
249 | * 0x39, 0x6b, 0x00, 0x00 addi r11,r11,sym@l | |
250 | * 0x7d, 0x69, 0x03, 0xa6 mtctr r11 | |
251 | * 0x4e, 0x80, 0x04, 0x20 bctr | |
7cc45e64 SR |
252 | */ |
253 | ||
021376a3 | 254 | pr_devel("ip:%lx jumps to %lx", ip, tramp); |
7cc45e64 SR |
255 | |
256 | /* Find where the trampoline jumps to */ | |
d9af12b7 | 257 | if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) { |
7cc45e64 SR |
258 | printk(KERN_ERR "Failed to read %lx\n", tramp); |
259 | return -EFAULT; | |
260 | } | |
261 | ||
021376a3 | 262 | pr_devel(" %08x %08x ", jmp[0], jmp[1]); |
d9af12b7 SR |
263 | |
264 | /* verify that this is what we expect it to be */ | |
265 | if (((jmp[0] & 0xffff0000) != 0x3d600000) || | |
266 | ((jmp[1] & 0xffff0000) != 0x396b0000) || | |
267 | (jmp[2] != 0x7d6903a6) || | |
268 | (jmp[3] != 0x4e800420)) { | |
269 | printk(KERN_ERR "Not a trampoline\n"); | |
270 | return -EINVAL; | |
271 | } | |
7cc45e64 | 272 | |
d9af12b7 SR |
273 | tramp = (jmp[1] & 0xffff) | |
274 | ((jmp[0] & 0xffff) << 16); | |
7cc45e64 SR |
275 | if (tramp & 0x8000) |
276 | tramp -= 0x10000; | |
277 | ||
021376a3 | 278 | pr_devel(" %lx ", tramp); |
7cc45e64 SR |
279 | |
280 | if (tramp != addr) { | |
281 | printk(KERN_ERR | |
282 | "Trampoline location %08lx does not match addr\n", | |
283 | tramp); | |
284 | return -EINVAL; | |
285 | } | |
286 | ||
16c57b36 | 287 | op = PPC_INST_NOP; |
7cc45e64 | 288 | |
d9af12b7 | 289 | if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE)) |
7cc45e64 SR |
290 | return -EPERM; |
291 | ||
ec682cef SR |
292 | flush_icache_range(ip, ip + 8); |
293 | ||
f48cb8b4 SR |
294 | return 0; |
295 | } | |
296 | #endif /* PPC64 */ | |
17be5b3d | 297 | #endif /* CONFIG_MODULES */ |
f48cb8b4 | 298 | |
8fd6e5a8 SR |
299 | int ftrace_make_nop(struct module *mod, |
300 | struct dyn_ftrace *rec, unsigned long addr) | |
301 | { | |
f48cb8b4 | 302 | unsigned long ip = rec->ip; |
b54dcfe1 | 303 | unsigned int old, new; |
8fd6e5a8 SR |
304 | |
305 | /* | |
306 | * If the calling address is more that 24 bits away, | |
307 | * then we had to use a trampoline to make the call. | |
308 | * Otherwise just update the call site. | |
309 | */ | |
f48cb8b4 | 310 | if (test_24bit_addr(ip, addr)) { |
8fd6e5a8 | 311 | /* within range */ |
46542888 | 312 | old = ftrace_call_replace(ip, addr, 1); |
92e02a51 | 313 | new = PPC_INST_NOP; |
f48cb8b4 SR |
314 | return ftrace_modify_code(ip, old, new); |
315 | } | |
316 | ||
17be5b3d | 317 | #ifdef CONFIG_MODULES |
f48cb8b4 SR |
318 | /* |
319 | * Out of range jumps are called from modules. | |
320 | * We should either already have a pointer to the module | |
321 | * or it has been passed in. | |
322 | */ | |
323 | if (!rec->arch.mod) { | |
324 | if (!mod) { | |
325 | printk(KERN_ERR "No module loaded addr=%lx\n", | |
326 | addr); | |
327 | return -EFAULT; | |
328 | } | |
329 | rec->arch.mod = mod; | |
330 | } else if (mod) { | |
331 | if (mod != rec->arch.mod) { | |
332 | printk(KERN_ERR | |
333 | "Record mod %p not equal to passed in mod %p\n", | |
334 | rec->arch.mod, mod); | |
335 | return -EINVAL; | |
336 | } | |
337 | /* nothing to do if mod == rec->arch.mod */ | |
338 | } else | |
339 | mod = rec->arch.mod; | |
f48cb8b4 SR |
340 | |
341 | return __ftrace_make_nop(mod, rec, addr); | |
17be5b3d SR |
342 | #else |
343 | /* We should not get here without modules */ | |
344 | return -EINVAL; | |
345 | #endif /* CONFIG_MODULES */ | |
f48cb8b4 SR |
346 | } |
347 | ||
17be5b3d | 348 | #ifdef CONFIG_MODULES |
f48cb8b4 SR |
349 | #ifdef CONFIG_PPC64 |
350 | static int | |
351 | __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) | |
352 | { | |
d9af12b7 | 353 | unsigned int op[2]; |
f48cb8b4 | 354 | unsigned long ip = rec->ip; |
f48cb8b4 SR |
355 | |
356 | /* read where this goes */ | |
d9af12b7 | 357 | if (probe_kernel_read(op, (void *)ip, MCOUNT_INSN_SIZE * 2)) |
f48cb8b4 SR |
358 | return -EFAULT; |
359 | ||
360 | /* | |
361 | * It should be pointing to two nops or | |
362 | * b +8; ld r2,40(r1) | |
363 | */ | |
364 | if (((op[0] != 0x48000008) || (op[1] != 0xe8410028)) && | |
16c57b36 | 365 | ((op[0] != PPC_INST_NOP) || (op[1] != PPC_INST_NOP))) { |
f48cb8b4 SR |
366 | printk(KERN_ERR "Expected NOPs but have %x %x\n", op[0], op[1]); |
367 | return -EINVAL; | |
368 | } | |
369 | ||
370 | /* If we never set up a trampoline to ftrace_caller, then bail */ | |
371 | if (!rec->arch.mod->arch.tramp) { | |
372 | printk(KERN_ERR "No ftrace trampoline\n"); | |
373 | return -EINVAL; | |
374 | } | |
375 | ||
0029ff87 SR |
376 | /* create the branch to the trampoline */ |
377 | op[0] = create_branch((unsigned int *)ip, | |
378 | rec->arch.mod->arch.tramp, BRANCH_SET_LINK); | |
379 | if (!op[0]) { | |
380 | printk(KERN_ERR "REL24 out of range!\n"); | |
f48cb8b4 | 381 | return -EINVAL; |
8fd6e5a8 SR |
382 | } |
383 | ||
f48cb8b4 SR |
384 | /* ld r2,40(r1) */ |
385 | op[1] = 0xe8410028; | |
386 | ||
021376a3 | 387 | pr_devel("write to %lx\n", rec->ip); |
f48cb8b4 | 388 | |
d9af12b7 | 389 | if (probe_kernel_write((void *)ip, op, MCOUNT_INSN_SIZE * 2)) |
f48cb8b4 SR |
390 | return -EPERM; |
391 | ||
ec682cef SR |
392 | flush_icache_range(ip, ip + 8); |
393 | ||
8fd6e5a8 SR |
394 | return 0; |
395 | } | |
f48cb8b4 SR |
396 | #else |
397 | static int | |
398 | __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) | |
399 | { | |
d9af12b7 | 400 | unsigned int op; |
7cc45e64 | 401 | unsigned long ip = rec->ip; |
7cc45e64 SR |
402 | |
403 | /* read where this goes */ | |
d9af12b7 | 404 | if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE)) |
7cc45e64 SR |
405 | return -EFAULT; |
406 | ||
407 | /* It should be pointing to a nop */ | |
16c57b36 | 408 | if (op != PPC_INST_NOP) { |
d9af12b7 | 409 | printk(KERN_ERR "Expected NOP but have %x\n", op); |
7cc45e64 SR |
410 | return -EINVAL; |
411 | } | |
412 | ||
413 | /* If we never set up a trampoline to ftrace_caller, then bail */ | |
414 | if (!rec->arch.mod->arch.tramp) { | |
415 | printk(KERN_ERR "No ftrace trampoline\n"); | |
416 | return -EINVAL; | |
417 | } | |
418 | ||
0029ff87 SR |
419 | /* create the branch to the trampoline */ |
420 | op = create_branch((unsigned int *)ip, | |
421 | rec->arch.mod->arch.tramp, BRANCH_SET_LINK); | |
422 | if (!op) { | |
423 | printk(KERN_ERR "REL24 out of range!\n"); | |
7cc45e64 SR |
424 | return -EINVAL; |
425 | } | |
426 | ||
021376a3 | 427 | pr_devel("write to %lx\n", rec->ip); |
7cc45e64 | 428 | |
d9af12b7 | 429 | if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE)) |
7cc45e64 SR |
430 | return -EPERM; |
431 | ||
ec682cef SR |
432 | flush_icache_range(ip, ip + 8); |
433 | ||
f48cb8b4 SR |
434 | return 0; |
435 | } | |
436 | #endif /* CONFIG_PPC64 */ | |
17be5b3d | 437 | #endif /* CONFIG_MODULES */ |
8fd6e5a8 SR |
438 | |
439 | int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) | |
440 | { | |
f48cb8b4 | 441 | unsigned long ip = rec->ip; |
b54dcfe1 | 442 | unsigned int old, new; |
8fd6e5a8 SR |
443 | |
444 | /* | |
445 | * If the calling address is more that 24 bits away, | |
446 | * then we had to use a trampoline to make the call. | |
447 | * Otherwise just update the call site. | |
448 | */ | |
f48cb8b4 | 449 | if (test_24bit_addr(ip, addr)) { |
8fd6e5a8 | 450 | /* within range */ |
92e02a51 | 451 | old = PPC_INST_NOP; |
46542888 | 452 | new = ftrace_call_replace(ip, addr, 1); |
f48cb8b4 | 453 | return ftrace_modify_code(ip, old, new); |
8fd6e5a8 SR |
454 | } |
455 | ||
17be5b3d | 456 | #ifdef CONFIG_MODULES |
f48cb8b4 SR |
457 | /* |
458 | * Out of range jumps are called from modules. | |
459 | * Being that we are converting from nop, it had better | |
460 | * already have a module defined. | |
461 | */ | |
462 | if (!rec->arch.mod) { | |
463 | printk(KERN_ERR "No module loaded\n"); | |
464 | return -EINVAL; | |
465 | } | |
f48cb8b4 SR |
466 | |
467 | return __ftrace_make_call(rec, addr); | |
17be5b3d SR |
468 | #else |
469 | /* We should not get here without modules */ | |
470 | return -EINVAL; | |
471 | #endif /* CONFIG_MODULES */ | |
8fd6e5a8 SR |
472 | } |
473 | ||
15adc048 | 474 | int ftrace_update_ftrace_func(ftrace_func_t func) |
4e491d14 SR |
475 | { |
476 | unsigned long ip = (unsigned long)(&ftrace_call); | |
b54dcfe1 | 477 | unsigned int old, new; |
4e491d14 SR |
478 | int ret; |
479 | ||
b54dcfe1 | 480 | old = *(unsigned int *)&ftrace_call; |
46542888 | 481 | new = ftrace_call_replace(ip, (unsigned long)func, 1); |
4e491d14 SR |
482 | ret = ftrace_modify_code(ip, old, new); |
483 | ||
484 | return ret; | |
485 | } | |
486 | ||
4e491d14 SR |
487 | int __init ftrace_dyn_arch_init(void *data) |
488 | { | |
8fd6e5a8 SR |
489 | /* caller expects data to be zero */ |
490 | unsigned long *p = data; | |
4e491d14 | 491 | |
8fd6e5a8 | 492 | *p = 0; |
4e491d14 SR |
493 | |
494 | return 0; | |
495 | } | |
6794c782 SR |
496 | #endif /* CONFIG_DYNAMIC_FTRACE */ |
497 | ||
498 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER | |
499 | ||
46542888 SR |
500 | #ifdef CONFIG_DYNAMIC_FTRACE |
501 | extern void ftrace_graph_call(void); | |
502 | extern void ftrace_graph_stub(void); | |
503 | ||
504 | int ftrace_enable_ftrace_graph_caller(void) | |
505 | { | |
506 | unsigned long ip = (unsigned long)(&ftrace_graph_call); | |
507 | unsigned long addr = (unsigned long)(&ftrace_graph_caller); | |
508 | unsigned long stub = (unsigned long)(&ftrace_graph_stub); | |
b54dcfe1 | 509 | unsigned int old, new; |
46542888 | 510 | |
b54dcfe1 | 511 | old = ftrace_call_replace(ip, stub, 0); |
46542888 SR |
512 | new = ftrace_call_replace(ip, addr, 0); |
513 | ||
514 | return ftrace_modify_code(ip, old, new); | |
515 | } | |
516 | ||
517 | int ftrace_disable_ftrace_graph_caller(void) | |
518 | { | |
519 | unsigned long ip = (unsigned long)(&ftrace_graph_call); | |
520 | unsigned long addr = (unsigned long)(&ftrace_graph_caller); | |
521 | unsigned long stub = (unsigned long)(&ftrace_graph_stub); | |
b54dcfe1 | 522 | unsigned int old, new; |
46542888 | 523 | |
b54dcfe1 | 524 | old = ftrace_call_replace(ip, addr, 0); |
46542888 SR |
525 | new = ftrace_call_replace(ip, stub, 0); |
526 | ||
527 | return ftrace_modify_code(ip, old, new); | |
528 | } | |
529 | #endif /* CONFIG_DYNAMIC_FTRACE */ | |
530 | ||
bb725340 SR |
531 | #ifdef CONFIG_PPC64 |
532 | extern void mod_return_to_handler(void); | |
533 | #endif | |
534 | ||
6794c782 SR |
535 | /* |
536 | * Hook the return address and push it in the stack of return addrs | |
537 | * in current thread info. | |
538 | */ | |
539 | void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) | |
540 | { | |
541 | unsigned long old; | |
6794c782 SR |
542 | int faulted; |
543 | struct ftrace_graph_ent trace; | |
bb725340 | 544 | unsigned long return_hooker = (unsigned long)&return_to_handler; |
6794c782 SR |
545 | |
546 | if (unlikely(atomic_read(¤t->tracing_graph_pause))) | |
547 | return; | |
548 | ||
f4952f6c | 549 | #ifdef CONFIG_PPC64 |
bb725340 SR |
550 | /* non core kernel code needs to save and restore the TOC */ |
551 | if (REGION_ID(self_addr) != KERNEL_REGION_ID) | |
552 | return_hooker = (unsigned long)&mod_return_to_handler; | |
553 | #endif | |
554 | ||
4a9e3f8e | 555 | return_hooker = ppc_function_entry((void *)return_hooker); |
6794c782 SR |
556 | |
557 | /* | |
558 | * Protect against fault, even if it shouldn't | |
559 | * happen. This tool is too much intrusive to | |
560 | * ignore such a protection. | |
561 | */ | |
562 | asm volatile( | |
563 | "1: " PPC_LL "%[old], 0(%[parent])\n" | |
564 | "2: " PPC_STL "%[return_hooker], 0(%[parent])\n" | |
565 | " li %[faulted], 0\n" | |
fad4f47c | 566 | "3:\n" |
6794c782 SR |
567 | |
568 | ".section .fixup, \"ax\"\n" | |
569 | "4: li %[faulted], 1\n" | |
570 | " b 3b\n" | |
571 | ".previous\n" | |
572 | ||
573 | ".section __ex_table,\"a\"\n" | |
574 | PPC_LONG_ALIGN "\n" | |
575 | PPC_LONG "1b,4b\n" | |
576 | PPC_LONG "2b,4b\n" | |
577 | ".previous" | |
578 | ||
c3cf8667 | 579 | : [old] "=&r" (old), [faulted] "=r" (faulted) |
6794c782 SR |
580 | : [parent] "r" (parent), [return_hooker] "r" (return_hooker) |
581 | : "memory" | |
582 | ); | |
583 | ||
584 | if (unlikely(faulted)) { | |
585 | ftrace_graph_stop(); | |
586 | WARN_ON(1); | |
587 | return; | |
588 | } | |
589 | ||
71e308a2 | 590 | if (ftrace_push_return_trace(old, self_addr, &trace.depth, 0) == -EBUSY) { |
6794c782 SR |
591 | *parent = old; |
592 | return; | |
593 | } | |
594 | ||
595 | trace.func = self_addr; | |
596 | ||
597 | /* Only trace if the calling function expects to */ | |
598 | if (!ftrace_graph_entry(&trace)) { | |
599 | current->curr_ret_stack--; | |
600 | *parent = old; | |
601 | } | |
602 | } | |
603 | #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ | |
02424d89 IM |
604 | |
605 | #if defined(CONFIG_FTRACE_SYSCALLS) && defined(CONFIG_PPC64) | |
606 | unsigned long __init arch_syscall_addr(int nr) | |
607 | { | |
608 | return sys_call_table[nr*2]; | |
609 | } | |
610 | #endif /* CONFIG_FTRACE_SYSCALLS && CONFIG_PPC64 */ |