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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Code for replacing ftrace calls with jumps.
4 *
5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
6 *
7 * Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box.
8 *
9 * Added function graph tracer code, taken from x86 that was written
10 * by Frederic Weisbecker, and ported to PPC by Steven Rostedt.
11 *
12 */
13
14#define pr_fmt(fmt) "ftrace-powerpc: " fmt
15
16#include <linux/spinlock.h>
17#include <linux/hardirq.h>
18#include <linux/uaccess.h>
19#include <linux/module.h>
20#include <linux/ftrace.h>
21#include <linux/percpu.h>
22#include <linux/init.h>
23#include <linux/list.h>
24
25#include <asm/cacheflush.h>
26#include <asm/code-patching.h>
27#include <asm/ftrace.h>
28#include <asm/syscall.h>
29#include <asm/inst.h>
30#include <asm/sections.h>
31
32#define NUM_FTRACE_TRAMPS 2
33static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS];
34
35unsigned long ftrace_call_adjust(unsigned long addr)
36{
37 if (addr >= (unsigned long)__exittext_begin && addr < (unsigned long)__exittext_end)
38 return 0;
39
40 if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY))
41 addr += MCOUNT_INSN_SIZE;
42
43 return addr;
44}
45
46static ppc_inst_t ftrace_create_branch_inst(unsigned long ip, unsigned long addr, int link)
47{
48 ppc_inst_t op;
49
50 WARN_ON(!is_offset_in_branch_range(addr - ip));
51 create_branch(&op, (u32 *)ip, addr, link ? BRANCH_SET_LINK : 0);
52
53 return op;
54}
55
56static inline int ftrace_read_inst(unsigned long ip, ppc_inst_t *op)
57{
58 if (copy_inst_from_kernel_nofault(op, (void *)ip)) {
59 pr_err("0x%lx: fetching instruction failed\n", ip);
60 return -EFAULT;
61 }
62
63 return 0;
64}
65
66static inline int ftrace_validate_inst(unsigned long ip, ppc_inst_t inst)
67{
68 ppc_inst_t op;
69 int ret;
70
71 ret = ftrace_read_inst(ip, &op);
72 if (!ret && !ppc_inst_equal(op, inst)) {
73 pr_err("0x%lx: expected (%08lx) != found (%08lx)\n",
74 ip, ppc_inst_as_ulong(inst), ppc_inst_as_ulong(op));
75 ret = -EINVAL;
76 }
77
78 return ret;
79}
80
81static inline int ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_t new)
82{
83 int ret = ftrace_validate_inst(ip, old);
84
85 if (!ret)
86 ret = patch_instruction((u32 *)ip, new);
87
88 return ret;
89}
90
91static int is_bl_op(ppc_inst_t op)
92{
93 return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BL(0);
94}
95
96static unsigned long find_ftrace_tramp(unsigned long ip)
97{
98 int i;
99
100 for (i = 0; i < NUM_FTRACE_TRAMPS; i++)
101 if (!ftrace_tramps[i])
102 continue;
103 else if (is_offset_in_branch_range(ftrace_tramps[i] - ip))
104 return ftrace_tramps[i];
105
106 return 0;
107}
108
109static int ftrace_get_call_inst(struct dyn_ftrace *rec, unsigned long addr, ppc_inst_t *call_inst)
110{
111 unsigned long ip = rec->ip;
112 unsigned long stub;
113
114 if (is_offset_in_branch_range(addr - ip)) {
115 /* Within range */
116 stub = addr;
117#ifdef CONFIG_MODULES
118 } else if (rec->arch.mod) {
119 /* Module code would be going to one of the module stubs */
120 stub = (addr == (unsigned long)ftrace_caller ? rec->arch.mod->arch.tramp :
121 rec->arch.mod->arch.tramp_regs);
122#endif
123 } else if (core_kernel_text(ip)) {
124 /* We would be branching to one of our ftrace stubs */
125 stub = find_ftrace_tramp(ip);
126 if (!stub) {
127 pr_err("0x%lx: No ftrace stubs reachable\n", ip);
128 return -EINVAL;
129 }
130 } else {
131 return -EINVAL;
132 }
133
134 *call_inst = ftrace_create_branch_inst(ip, stub, 1);
135 return 0;
136}
137
138#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
139int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr)
140{
141 /* This should never be called since we override ftrace_replace_code() */
142 WARN_ON(1);
143 return -EINVAL;
144}
145#endif
146
147int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
148{
149 ppc_inst_t old, new;
150 int ret;
151
152 /* This can only ever be called during module load */
153 if (WARN_ON(!IS_ENABLED(CONFIG_MODULES) || core_kernel_text(rec->ip)))
154 return -EINVAL;
155
156 old = ppc_inst(PPC_RAW_NOP());
157 ret = ftrace_get_call_inst(rec, addr, &new);
158 if (ret)
159 return ret;
160
161 return ftrace_modify_code(rec->ip, old, new);
162}
163
164int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr)
165{
166 /*
167 * This should never be called since we override ftrace_replace_code(),
168 * as well as ftrace_init_nop()
169 */
170 WARN_ON(1);
171 return -EINVAL;
172}
173
174void ftrace_replace_code(int enable)
175{
176 ppc_inst_t old, new, call_inst, new_call_inst;
177 ppc_inst_t nop_inst = ppc_inst(PPC_RAW_NOP());
178 unsigned long ip, new_addr, addr;
179 struct ftrace_rec_iter *iter;
180 struct dyn_ftrace *rec;
181 int ret = 0, update;
182
183 for_ftrace_rec_iter(iter) {
184 rec = ftrace_rec_iter_record(iter);
185 ip = rec->ip;
186
187 if (rec->flags & FTRACE_FL_DISABLED && !(rec->flags & FTRACE_FL_ENABLED))
188 continue;
189
190 addr = ftrace_get_addr_curr(rec);
191 new_addr = ftrace_get_addr_new(rec);
192 update = ftrace_update_record(rec, enable);
193
194 switch (update) {
195 case FTRACE_UPDATE_IGNORE:
196 default:
197 continue;
198 case FTRACE_UPDATE_MODIFY_CALL:
199 ret = ftrace_get_call_inst(rec, new_addr, &new_call_inst);
200 ret |= ftrace_get_call_inst(rec, addr, &call_inst);
201 old = call_inst;
202 new = new_call_inst;
203 break;
204 case FTRACE_UPDATE_MAKE_NOP:
205 ret = ftrace_get_call_inst(rec, addr, &call_inst);
206 old = call_inst;
207 new = nop_inst;
208 break;
209 case FTRACE_UPDATE_MAKE_CALL:
210 ret = ftrace_get_call_inst(rec, new_addr, &call_inst);
211 old = nop_inst;
212 new = call_inst;
213 break;
214 }
215
216 if (!ret)
217 ret = ftrace_modify_code(ip, old, new);
218 if (ret)
219 goto out;
220 }
221
222out:
223 if (ret)
224 ftrace_bug(ret, rec);
225 return;
226}
227
228int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
229{
230 unsigned long addr, ip = rec->ip;
231 ppc_inst_t old, new;
232 int ret = 0;
233
234 /* Verify instructions surrounding the ftrace location */
235 if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) {
236 /* Expect nops */
237 ret = ftrace_validate_inst(ip - 4, ppc_inst(PPC_RAW_NOP()));
238 if (!ret)
239 ret = ftrace_validate_inst(ip, ppc_inst(PPC_RAW_NOP()));
240 } else if (IS_ENABLED(CONFIG_PPC32)) {
241 /* Expected sequence: 'mflr r0', 'stw r0,4(r1)', 'bl _mcount' */
242 ret = ftrace_validate_inst(ip - 8, ppc_inst(PPC_RAW_MFLR(_R0)));
243 if (!ret)
244 ret = ftrace_validate_inst(ip - 4, ppc_inst(PPC_RAW_STW(_R0, _R1, 4)));
245 } else if (IS_ENABLED(CONFIG_MPROFILE_KERNEL)) {
246 /* Expected sequence: 'mflr r0', ['std r0,16(r1)'], 'bl _mcount' */
247 ret = ftrace_read_inst(ip - 4, &old);
248 if (!ret && !ppc_inst_equal(old, ppc_inst(PPC_RAW_MFLR(_R0)))) {
249 ret = ftrace_validate_inst(ip - 8, ppc_inst(PPC_RAW_MFLR(_R0)));
250 ret |= ftrace_validate_inst(ip - 4, ppc_inst(PPC_RAW_STD(_R0, _R1, 16)));
251 }
252 } else {
253 return -EINVAL;
254 }
255
256 if (ret)
257 return ret;
258
259 if (!core_kernel_text(ip)) {
260 if (!mod) {
261 pr_err("0x%lx: No module provided for non-kernel address\n", ip);
262 return -EFAULT;
263 }
264 rec->arch.mod = mod;
265 }
266
267 /* Nop-out the ftrace location */
268 new = ppc_inst(PPC_RAW_NOP());
269 addr = MCOUNT_ADDR;
270 if (IS_ENABLED(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)) {
271 /* we instead patch-in the 'mflr r0' */
272 old = ppc_inst(PPC_RAW_NOP());
273 new = ppc_inst(PPC_RAW_MFLR(_R0));
274 ret = ftrace_modify_code(ip - 4, old, new);
275 } else if (is_offset_in_branch_range(addr - ip)) {
276 /* Within range */
277 old = ftrace_create_branch_inst(ip, addr, 1);
278 ret = ftrace_modify_code(ip, old, new);
279 } else if (core_kernel_text(ip) || (IS_ENABLED(CONFIG_MODULES) && mod)) {
280 /*
281 * We would be branching to a linker-generated stub, or to the module _mcount
282 * stub. Let's just confirm we have a 'bl' here.
283 */
284 ret = ftrace_read_inst(ip, &old);
285 if (ret)
286 return ret;
287 if (!is_bl_op(old)) {
288 pr_err("0x%lx: expected (bl) != found (%08lx)\n", ip, ppc_inst_as_ulong(old));
289 return -EINVAL;
290 }
291 ret = patch_instruction((u32 *)ip, new);
292 } else {
293 return -EINVAL;
294 }
295
296 return ret;
297}
298
299int ftrace_update_ftrace_func(ftrace_func_t func)
300{
301 unsigned long ip = (unsigned long)(&ftrace_call);
302 ppc_inst_t old, new;
303 int ret;
304
305 old = ppc_inst_read((u32 *)&ftrace_call);
306 new = ftrace_create_branch_inst(ip, ppc_function_entry(func), 1);
307 ret = ftrace_modify_code(ip, old, new);
308
309 /* Also update the regs callback function */
310 if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && !ret) {
311 ip = (unsigned long)(&ftrace_regs_call);
312 old = ppc_inst_read((u32 *)&ftrace_regs_call);
313 new = ftrace_create_branch_inst(ip, ppc_function_entry(func), 1);
314 ret = ftrace_modify_code(ip, old, new);
315 }
316
317 return ret;
318}
319
320/*
321 * Use the default ftrace_modify_all_code, but without
322 * stop_machine().
323 */
324void arch_ftrace_update_code(int command)
325{
326 ftrace_modify_all_code(command);
327}
328
329void ftrace_free_init_tramp(void)
330{
331 int i;
332
333 for (i = 0; i < NUM_FTRACE_TRAMPS && ftrace_tramps[i]; i++)
334 if (ftrace_tramps[i] == (unsigned long)ftrace_tramp_init) {
335 ftrace_tramps[i] = 0;
336 return;
337 }
338}
339
340static void __init add_ftrace_tramp(unsigned long tramp)
341{
342 int i;
343
344 for (i = 0; i < NUM_FTRACE_TRAMPS; i++)
345 if (!ftrace_tramps[i]) {
346 ftrace_tramps[i] = tramp;
347 return;
348 }
349}
350
351int __init ftrace_dyn_arch_init(void)
352{
353 unsigned int *tramp[] = { ftrace_tramp_text, ftrace_tramp_init };
354 unsigned long addr = FTRACE_REGS_ADDR;
355 long reladdr;
356 int i;
357 u32 stub_insns[] = {
358#ifdef CONFIG_PPC_KERNEL_PCREL
359 /* pla r12,addr */
360 PPC_PREFIX_MLS | __PPC_PRFX_R(1),
361 PPC_INST_PADDI | ___PPC_RT(_R12),
362 PPC_RAW_MTCTR(_R12),
363 PPC_RAW_BCTR()
364#elif defined(CONFIG_PPC64)
365 PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernel_toc)),
366 PPC_RAW_ADDIS(_R12, _R12, 0),
367 PPC_RAW_ADDI(_R12, _R12, 0),
368 PPC_RAW_MTCTR(_R12),
369 PPC_RAW_BCTR()
370#else
371 PPC_RAW_LIS(_R12, 0),
372 PPC_RAW_ADDI(_R12, _R12, 0),
373 PPC_RAW_MTCTR(_R12),
374 PPC_RAW_BCTR()
375#endif
376 };
377
378 if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) {
379 for (i = 0; i < 2; i++) {
380 reladdr = addr - (unsigned long)tramp[i];
381
382 if (reladdr >= (long)SZ_8G || reladdr < -(long)SZ_8G) {
383 pr_err("Address of %ps out of range of pcrel address.\n",
384 (void *)addr);
385 return -1;
386 }
387
388 memcpy(tramp[i], stub_insns, sizeof(stub_insns));
389 tramp[i][0] |= IMM_H18(reladdr);
390 tramp[i][1] |= IMM_L(reladdr);
391 add_ftrace_tramp((unsigned long)tramp[i]);
392 }
393 } else if (IS_ENABLED(CONFIG_PPC64)) {
394 reladdr = addr - kernel_toc_addr();
395
396 if (reladdr >= (long)SZ_2G || reladdr < -(long long)SZ_2G) {
397 pr_err("Address of %ps out of range of kernel_toc.\n",
398 (void *)addr);
399 return -1;
400 }
401
402 for (i = 0; i < 2; i++) {
403 memcpy(tramp[i], stub_insns, sizeof(stub_insns));
404 tramp[i][1] |= PPC_HA(reladdr);
405 tramp[i][2] |= PPC_LO(reladdr);
406 add_ftrace_tramp((unsigned long)tramp[i]);
407 }
408 } else {
409 for (i = 0; i < 2; i++) {
410 memcpy(tramp[i], stub_insns, sizeof(stub_insns));
411 tramp[i][0] |= PPC_HA(addr);
412 tramp[i][1] |= PPC_LO(addr);
413 add_ftrace_tramp((unsigned long)tramp[i]);
414 }
415 }
416
417 return 0;
418}
419
420#ifdef CONFIG_FUNCTION_GRAPH_TRACER
421void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
422 struct ftrace_ops *op, struct ftrace_regs *fregs)
423{
424 unsigned long sp = fregs->regs.gpr[1];
425 int bit;
426
427 if (unlikely(ftrace_graph_is_dead()))
428 goto out;
429
430 if (unlikely(atomic_read(¤t->tracing_graph_pause)))
431 goto out;
432
433 bit = ftrace_test_recursion_trylock(ip, parent_ip);
434 if (bit < 0)
435 goto out;
436
437 if (!function_graph_enter(parent_ip, ip, 0, (unsigned long *)sp))
438 parent_ip = ppc_function_entry(return_to_handler);
439
440 ftrace_test_recursion_unlock(bit);
441out:
442 fregs->regs.link = parent_ip;
443}
444#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Code for replacing ftrace calls with jumps.
4 *
5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
6 *
7 * Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box.
8 *
9 * Added function graph tracer code, taken from x86 that was written
10 * by Frederic Weisbecker, and ported to PPC by Steven Rostedt.
11 *
12 */
13
14#define pr_fmt(fmt) "ftrace-powerpc: " fmt
15
16#include <linux/spinlock.h>
17#include <linux/hardirq.h>
18#include <linux/uaccess.h>
19#include <linux/module.h>
20#include <linux/ftrace.h>
21#include <linux/percpu.h>
22#include <linux/init.h>
23#include <linux/list.h>
24
25#include <asm/asm-prototypes.h>
26#include <asm/cacheflush.h>
27#include <asm/code-patching.h>
28#include <asm/ftrace.h>
29#include <asm/syscall.h>
30#include <asm/inst.h>
31
32
33#ifdef CONFIG_DYNAMIC_FTRACE
34
35/*
36 * We generally only have a single long_branch tramp and at most 2 or 3 plt
37 * tramps generated. But, we don't use the plt tramps currently. We also allot
38 * 2 tramps after .text and .init.text. So, we only end up with around 3 usable
39 * tramps in total. Set aside 8 just to be sure.
40 */
41#define NUM_FTRACE_TRAMPS 8
42static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS];
43
44static struct ppc_inst
45ftrace_call_replace(unsigned long ip, unsigned long addr, int link)
46{
47 struct ppc_inst op;
48
49 addr = ppc_function_entry((void *)addr);
50
51 /* if (link) set op to 'bl' else 'b' */
52 create_branch(&op, (struct ppc_inst *)ip, addr, link ? 1 : 0);
53
54 return op;
55}
56
57static int
58ftrace_modify_code(unsigned long ip, struct ppc_inst old, struct ppc_inst new)
59{
60 struct ppc_inst replaced;
61
62 /*
63 * Note:
64 * We are paranoid about modifying text, as if a bug was to happen, it
65 * could cause us to read or write to someplace that could cause harm.
66 * Carefully read and modify the code with probe_kernel_*(), and make
67 * sure what we read is what we expected it to be before modifying it.
68 */
69
70 /* read the text we want to modify */
71 if (probe_kernel_read_inst(&replaced, (void *)ip))
72 return -EFAULT;
73
74 /* Make sure it is what we expect it to be */
75 if (!ppc_inst_equal(replaced, old)) {
76 pr_err("%p: replaced (%s) != old (%s)",
77 (void *)ip, ppc_inst_as_str(replaced), ppc_inst_as_str(old));
78 return -EINVAL;
79 }
80
81 /* replace the text with the new text */
82 if (patch_instruction((struct ppc_inst *)ip, new))
83 return -EPERM;
84
85 return 0;
86}
87
88/*
89 * Helper functions that are the same for both PPC64 and PPC32.
90 */
91static int test_24bit_addr(unsigned long ip, unsigned long addr)
92{
93 struct ppc_inst op;
94 addr = ppc_function_entry((void *)addr);
95
96 /* use the create_branch to verify that this offset can be branched */
97 return create_branch(&op, (struct ppc_inst *)ip, addr, 0) == 0;
98}
99
100static int is_bl_op(struct ppc_inst op)
101{
102 return (ppc_inst_val(op) & 0xfc000003) == 0x48000001;
103}
104
105static int is_b_op(struct ppc_inst op)
106{
107 return (ppc_inst_val(op) & 0xfc000003) == 0x48000000;
108}
109
110static unsigned long find_bl_target(unsigned long ip, struct ppc_inst op)
111{
112 int offset;
113
114 offset = (ppc_inst_val(op) & 0x03fffffc);
115 /* make it signed */
116 if (offset & 0x02000000)
117 offset |= 0xfe000000;
118
119 return ip + (long)offset;
120}
121
122#ifdef CONFIG_MODULES
123#ifdef CONFIG_PPC64
124static int
125__ftrace_make_nop(struct module *mod,
126 struct dyn_ftrace *rec, unsigned long addr)
127{
128 unsigned long entry, ptr, tramp;
129 unsigned long ip = rec->ip;
130 struct ppc_inst op, pop;
131
132 /* read where this goes */
133 if (probe_kernel_read_inst(&op, (void *)ip)) {
134 pr_err("Fetching opcode failed.\n");
135 return -EFAULT;
136 }
137
138 /* Make sure that that this is still a 24bit jump */
139 if (!is_bl_op(op)) {
140 pr_err("Not expected bl: opcode is %s\n", ppc_inst_as_str(op));
141 return -EINVAL;
142 }
143
144 /* lets find where the pointer goes */
145 tramp = find_bl_target(ip, op);
146
147 pr_devel("ip:%lx jumps to %lx", ip, tramp);
148
149 if (module_trampoline_target(mod, tramp, &ptr)) {
150 pr_err("Failed to get trampoline target\n");
151 return -EFAULT;
152 }
153
154 pr_devel("trampoline target %lx", ptr);
155
156 entry = ppc_global_function_entry((void *)addr);
157 /* This should match what was called */
158 if (ptr != entry) {
159 pr_err("addr %lx does not match expected %lx\n", ptr, entry);
160 return -EINVAL;
161 }
162
163#ifdef CONFIG_MPROFILE_KERNEL
164 /* When using -mkernel_profile there is no load to jump over */
165 pop = ppc_inst(PPC_INST_NOP);
166
167 if (probe_kernel_read_inst(&op, (void *)(ip - 4))) {
168 pr_err("Fetching instruction at %lx failed.\n", ip - 4);
169 return -EFAULT;
170 }
171
172 /* We expect either a mflr r0, or a std r0, LRSAVE(r1) */
173 if (!ppc_inst_equal(op, ppc_inst(PPC_INST_MFLR)) &&
174 !ppc_inst_equal(op, ppc_inst(PPC_INST_STD_LR))) {
175 pr_err("Unexpected instruction %s around bl _mcount\n",
176 ppc_inst_as_str(op));
177 return -EINVAL;
178 }
179#else
180 /*
181 * Our original call site looks like:
182 *
183 * bl <tramp>
184 * ld r2,XX(r1)
185 *
186 * Milton Miller pointed out that we can not simply nop the branch.
187 * If a task was preempted when calling a trace function, the nops
188 * will remove the way to restore the TOC in r2 and the r2 TOC will
189 * get corrupted.
190 *
191 * Use a b +8 to jump over the load.
192 */
193
194 pop = ppc_inst(PPC_INST_BRANCH | 8); /* b +8 */
195
196 /*
197 * Check what is in the next instruction. We can see ld r2,40(r1), but
198 * on first pass after boot we will see mflr r0.
199 */
200 if (probe_kernel_read_inst(&op, (void *)(ip + 4))) {
201 pr_err("Fetching op failed.\n");
202 return -EFAULT;
203 }
204
205 if (!ppc_inst_equal(op, ppc_inst(PPC_INST_LD_TOC))) {
206 pr_err("Expected %08x found %s\n", PPC_INST_LD_TOC, ppc_inst_as_str(op));
207 return -EINVAL;
208 }
209#endif /* CONFIG_MPROFILE_KERNEL */
210
211 if (patch_instruction((struct ppc_inst *)ip, pop)) {
212 pr_err("Patching NOP failed.\n");
213 return -EPERM;
214 }
215
216 return 0;
217}
218
219#else /* !PPC64 */
220static int
221__ftrace_make_nop(struct module *mod,
222 struct dyn_ftrace *rec, unsigned long addr)
223{
224 struct ppc_inst op;
225 unsigned int jmp[4];
226 unsigned long ip = rec->ip;
227 unsigned long tramp;
228
229 if (copy_from_kernel_nofault(&op, (void *)ip, MCOUNT_INSN_SIZE))
230 return -EFAULT;
231
232 /* Make sure that that this is still a 24bit jump */
233 if (!is_bl_op(op)) {
234 pr_err("Not expected bl: opcode is %s\n", ppc_inst_as_str(op));
235 return -EINVAL;
236 }
237
238 /* lets find where the pointer goes */
239 tramp = find_bl_target(ip, op);
240
241 /*
242 * On PPC32 the trampoline looks like:
243 * 0x3d, 0x80, 0x00, 0x00 lis r12,sym@ha
244 * 0x39, 0x8c, 0x00, 0x00 addi r12,r12,sym@l
245 * 0x7d, 0x89, 0x03, 0xa6 mtctr r12
246 * 0x4e, 0x80, 0x04, 0x20 bctr
247 */
248
249 pr_devel("ip:%lx jumps to %lx", ip, tramp);
250
251 /* Find where the trampoline jumps to */
252 if (copy_from_kernel_nofault(jmp, (void *)tramp, sizeof(jmp))) {
253 pr_err("Failed to read %lx\n", tramp);
254 return -EFAULT;
255 }
256
257 pr_devel(" %08x %08x ", jmp[0], jmp[1]);
258
259 /* verify that this is what we expect it to be */
260 if (((jmp[0] & 0xffff0000) != 0x3d800000) ||
261 ((jmp[1] & 0xffff0000) != 0x398c0000) ||
262 (jmp[2] != 0x7d8903a6) ||
263 (jmp[3] != 0x4e800420)) {
264 pr_err("Not a trampoline\n");
265 return -EINVAL;
266 }
267
268 tramp = (jmp[1] & 0xffff) |
269 ((jmp[0] & 0xffff) << 16);
270 if (tramp & 0x8000)
271 tramp -= 0x10000;
272
273 pr_devel(" %lx ", tramp);
274
275 if (tramp != addr) {
276 pr_err("Trampoline location %08lx does not match addr\n",
277 tramp);
278 return -EINVAL;
279 }
280
281 op = ppc_inst(PPC_INST_NOP);
282
283 if (patch_instruction((struct ppc_inst *)ip, op))
284 return -EPERM;
285
286 return 0;
287}
288#endif /* PPC64 */
289#endif /* CONFIG_MODULES */
290
291static unsigned long find_ftrace_tramp(unsigned long ip)
292{
293 int i;
294 struct ppc_inst instr;
295
296 /*
297 * We have the compiler generated long_branch tramps at the end
298 * and we prefer those
299 */
300 for (i = NUM_FTRACE_TRAMPS - 1; i >= 0; i--)
301 if (!ftrace_tramps[i])
302 continue;
303 else if (create_branch(&instr, (void *)ip,
304 ftrace_tramps[i], 0) == 0)
305 return ftrace_tramps[i];
306
307 return 0;
308}
309
310static int add_ftrace_tramp(unsigned long tramp)
311{
312 int i;
313
314 for (i = 0; i < NUM_FTRACE_TRAMPS; i++)
315 if (!ftrace_tramps[i]) {
316 ftrace_tramps[i] = tramp;
317 return 0;
318 }
319
320 return -1;
321}
322
323/*
324 * If this is a compiler generated long_branch trampoline (essentially, a
325 * trampoline that has a branch to _mcount()), we re-write the branch to
326 * instead go to ftrace_[regs_]caller() and note down the location of this
327 * trampoline.
328 */
329static int setup_mcount_compiler_tramp(unsigned long tramp)
330{
331 int i;
332 struct ppc_inst op;
333 unsigned long ptr;
334 struct ppc_inst instr;
335 static unsigned long ftrace_plt_tramps[NUM_FTRACE_TRAMPS];
336
337 /* Is this a known long jump tramp? */
338 for (i = 0; i < NUM_FTRACE_TRAMPS; i++)
339 if (!ftrace_tramps[i])
340 break;
341 else if (ftrace_tramps[i] == tramp)
342 return 0;
343
344 /* Is this a known plt tramp? */
345 for (i = 0; i < NUM_FTRACE_TRAMPS; i++)
346 if (!ftrace_plt_tramps[i])
347 break;
348 else if (ftrace_plt_tramps[i] == tramp)
349 return -1;
350
351 /* New trampoline -- read where this goes */
352 if (probe_kernel_read_inst(&op, (void *)tramp)) {
353 pr_debug("Fetching opcode failed.\n");
354 return -1;
355 }
356
357 /* Is this a 24 bit branch? */
358 if (!is_b_op(op)) {
359 pr_debug("Trampoline is not a long branch tramp.\n");
360 return -1;
361 }
362
363 /* lets find where the pointer goes */
364 ptr = find_bl_target(tramp, op);
365
366 if (ptr != ppc_global_function_entry((void *)_mcount)) {
367 pr_debug("Trampoline target %p is not _mcount\n", (void *)ptr);
368 return -1;
369 }
370
371 /* Let's re-write the tramp to go to ftrace_[regs_]caller */
372#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
373 ptr = ppc_global_function_entry((void *)ftrace_regs_caller);
374#else
375 ptr = ppc_global_function_entry((void *)ftrace_caller);
376#endif
377 if (create_branch(&instr, (void *)tramp, ptr, 0)) {
378 pr_debug("%ps is not reachable from existing mcount tramp\n",
379 (void *)ptr);
380 return -1;
381 }
382
383 if (patch_branch((struct ppc_inst *)tramp, ptr, 0)) {
384 pr_debug("REL24 out of range!\n");
385 return -1;
386 }
387
388 if (add_ftrace_tramp(tramp)) {
389 pr_debug("No tramp locations left\n");
390 return -1;
391 }
392
393 return 0;
394}
395
396static int __ftrace_make_nop_kernel(struct dyn_ftrace *rec, unsigned long addr)
397{
398 unsigned long tramp, ip = rec->ip;
399 struct ppc_inst op;
400
401 /* Read where this goes */
402 if (probe_kernel_read_inst(&op, (void *)ip)) {
403 pr_err("Fetching opcode failed.\n");
404 return -EFAULT;
405 }
406
407 /* Make sure that that this is still a 24bit jump */
408 if (!is_bl_op(op)) {
409 pr_err("Not expected bl: opcode is %s\n", ppc_inst_as_str(op));
410 return -EINVAL;
411 }
412
413 /* Let's find where the pointer goes */
414 tramp = find_bl_target(ip, op);
415
416 pr_devel("ip:%lx jumps to %lx", ip, tramp);
417
418 if (setup_mcount_compiler_tramp(tramp)) {
419 /* Are other trampolines reachable? */
420 if (!find_ftrace_tramp(ip)) {
421 pr_err("No ftrace trampolines reachable from %ps\n",
422 (void *)ip);
423 return -EINVAL;
424 }
425 }
426
427 if (patch_instruction((struct ppc_inst *)ip, ppc_inst(PPC_INST_NOP))) {
428 pr_err("Patching NOP failed.\n");
429 return -EPERM;
430 }
431
432 return 0;
433}
434
435int ftrace_make_nop(struct module *mod,
436 struct dyn_ftrace *rec, unsigned long addr)
437{
438 unsigned long ip = rec->ip;
439 struct ppc_inst old, new;
440
441 /*
442 * If the calling address is more that 24 bits away,
443 * then we had to use a trampoline to make the call.
444 * Otherwise just update the call site.
445 */
446 if (test_24bit_addr(ip, addr)) {
447 /* within range */
448 old = ftrace_call_replace(ip, addr, 1);
449 new = ppc_inst(PPC_INST_NOP);
450 return ftrace_modify_code(ip, old, new);
451 } else if (core_kernel_text(ip))
452 return __ftrace_make_nop_kernel(rec, addr);
453
454#ifdef CONFIG_MODULES
455 /*
456 * Out of range jumps are called from modules.
457 * We should either already have a pointer to the module
458 * or it has been passed in.
459 */
460 if (!rec->arch.mod) {
461 if (!mod) {
462 pr_err("No module loaded addr=%lx\n", addr);
463 return -EFAULT;
464 }
465 rec->arch.mod = mod;
466 } else if (mod) {
467 if (mod != rec->arch.mod) {
468 pr_err("Record mod %p not equal to passed in mod %p\n",
469 rec->arch.mod, mod);
470 return -EINVAL;
471 }
472 /* nothing to do if mod == rec->arch.mod */
473 } else
474 mod = rec->arch.mod;
475
476 return __ftrace_make_nop(mod, rec, addr);
477#else
478 /* We should not get here without modules */
479 return -EINVAL;
480#endif /* CONFIG_MODULES */
481}
482
483#ifdef CONFIG_MODULES
484#ifdef CONFIG_PPC64
485/*
486 * Examine the existing instructions for __ftrace_make_call.
487 * They should effectively be a NOP, and follow formal constraints,
488 * depending on the ABI. Return false if they don't.
489 */
490#ifndef CONFIG_MPROFILE_KERNEL
491static int
492expected_nop_sequence(void *ip, struct ppc_inst op0, struct ppc_inst op1)
493{
494 /*
495 * We expect to see:
496 *
497 * b +8
498 * ld r2,XX(r1)
499 *
500 * The load offset is different depending on the ABI. For simplicity
501 * just mask it out when doing the compare.
502 */
503 if (!ppc_inst_equal(op0, ppc_inst(0x48000008)) ||
504 (ppc_inst_val(op1) & 0xffff0000) != 0xe8410000)
505 return 0;
506 return 1;
507}
508#else
509static int
510expected_nop_sequence(void *ip, struct ppc_inst op0, struct ppc_inst op1)
511{
512 /* look for patched "NOP" on ppc64 with -mprofile-kernel */
513 if (!ppc_inst_equal(op0, ppc_inst(PPC_INST_NOP)))
514 return 0;
515 return 1;
516}
517#endif
518
519static int
520__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
521{
522 struct ppc_inst op[2];
523 struct ppc_inst instr;
524 void *ip = (void *)rec->ip;
525 unsigned long entry, ptr, tramp;
526 struct module *mod = rec->arch.mod;
527
528 /* read where this goes */
529 if (probe_kernel_read_inst(op, ip))
530 return -EFAULT;
531
532 if (probe_kernel_read_inst(op + 1, ip + 4))
533 return -EFAULT;
534
535 if (!expected_nop_sequence(ip, op[0], op[1])) {
536 pr_err("Unexpected call sequence at %p: %s %s\n",
537 ip, ppc_inst_as_str(op[0]), ppc_inst_as_str(op[1]));
538 return -EINVAL;
539 }
540
541 /* If we never set up ftrace trampoline(s), then bail */
542#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
543 if (!mod->arch.tramp || !mod->arch.tramp_regs) {
544#else
545 if (!mod->arch.tramp) {
546#endif
547 pr_err("No ftrace trampoline\n");
548 return -EINVAL;
549 }
550
551#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
552 if (rec->flags & FTRACE_FL_REGS)
553 tramp = mod->arch.tramp_regs;
554 else
555#endif
556 tramp = mod->arch.tramp;
557
558 if (module_trampoline_target(mod, tramp, &ptr)) {
559 pr_err("Failed to get trampoline target\n");
560 return -EFAULT;
561 }
562
563 pr_devel("trampoline target %lx", ptr);
564
565 entry = ppc_global_function_entry((void *)addr);
566 /* This should match what was called */
567 if (ptr != entry) {
568 pr_err("addr %lx does not match expected %lx\n", ptr, entry);
569 return -EINVAL;
570 }
571
572 /* Ensure branch is within 24 bits */
573 if (create_branch(&instr, ip, tramp, BRANCH_SET_LINK)) {
574 pr_err("Branch out of range\n");
575 return -EINVAL;
576 }
577
578 if (patch_branch(ip, tramp, BRANCH_SET_LINK)) {
579 pr_err("REL24 out of range!\n");
580 return -EINVAL;
581 }
582
583 return 0;
584}
585
586#else /* !CONFIG_PPC64: */
587static int
588__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
589{
590 int err;
591 struct ppc_inst op;
592 unsigned long ip = rec->ip;
593
594 /* read where this goes */
595 if (probe_kernel_read_inst(&op, (void *)ip))
596 return -EFAULT;
597
598 /* It should be pointing to a nop */
599 if (!ppc_inst_equal(op, ppc_inst(PPC_INST_NOP))) {
600 pr_err("Expected NOP but have %s\n", ppc_inst_as_str(op));
601 return -EINVAL;
602 }
603
604 /* If we never set up a trampoline to ftrace_caller, then bail */
605 if (!rec->arch.mod->arch.tramp) {
606 pr_err("No ftrace trampoline\n");
607 return -EINVAL;
608 }
609
610 /* create the branch to the trampoline */
611 err = create_branch(&op, (struct ppc_inst *)ip,
612 rec->arch.mod->arch.tramp, BRANCH_SET_LINK);
613 if (err) {
614 pr_err("REL24 out of range!\n");
615 return -EINVAL;
616 }
617
618 pr_devel("write to %lx\n", rec->ip);
619
620 if (patch_instruction((struct ppc_inst *)ip, op))
621 return -EPERM;
622
623 return 0;
624}
625#endif /* CONFIG_PPC64 */
626#endif /* CONFIG_MODULES */
627
628static int __ftrace_make_call_kernel(struct dyn_ftrace *rec, unsigned long addr)
629{
630 struct ppc_inst op;
631 void *ip = (void *)rec->ip;
632 unsigned long tramp, entry, ptr;
633
634 /* Make sure we're being asked to patch branch to a known ftrace addr */
635 entry = ppc_global_function_entry((void *)ftrace_caller);
636 ptr = ppc_global_function_entry((void *)addr);
637
638 if (ptr != entry) {
639#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
640 entry = ppc_global_function_entry((void *)ftrace_regs_caller);
641 if (ptr != entry) {
642#endif
643 pr_err("Unknown ftrace addr to patch: %ps\n", (void *)ptr);
644 return -EINVAL;
645#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
646 }
647#endif
648 }
649
650 /* Make sure we have a nop */
651 if (probe_kernel_read_inst(&op, ip)) {
652 pr_err("Unable to read ftrace location %p\n", ip);
653 return -EFAULT;
654 }
655
656 if (!ppc_inst_equal(op, ppc_inst(PPC_INST_NOP))) {
657 pr_err("Unexpected call sequence at %p: %s\n", ip, ppc_inst_as_str(op));
658 return -EINVAL;
659 }
660
661 tramp = find_ftrace_tramp((unsigned long)ip);
662 if (!tramp) {
663 pr_err("No ftrace trampolines reachable from %ps\n", ip);
664 return -EINVAL;
665 }
666
667 if (patch_branch(ip, tramp, BRANCH_SET_LINK)) {
668 pr_err("Error patching branch to ftrace tramp!\n");
669 return -EINVAL;
670 }
671
672 return 0;
673}
674
675int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
676{
677 unsigned long ip = rec->ip;
678 struct ppc_inst old, new;
679
680 /*
681 * If the calling address is more that 24 bits away,
682 * then we had to use a trampoline to make the call.
683 * Otherwise just update the call site.
684 */
685 if (test_24bit_addr(ip, addr)) {
686 /* within range */
687 old = ppc_inst(PPC_INST_NOP);
688 new = ftrace_call_replace(ip, addr, 1);
689 return ftrace_modify_code(ip, old, new);
690 } else if (core_kernel_text(ip))
691 return __ftrace_make_call_kernel(rec, addr);
692
693#ifdef CONFIG_MODULES
694 /*
695 * Out of range jumps are called from modules.
696 * Being that we are converting from nop, it had better
697 * already have a module defined.
698 */
699 if (!rec->arch.mod) {
700 pr_err("No module loaded\n");
701 return -EINVAL;
702 }
703
704 return __ftrace_make_call(rec, addr);
705#else
706 /* We should not get here without modules */
707 return -EINVAL;
708#endif /* CONFIG_MODULES */
709}
710
711#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
712#ifdef CONFIG_MODULES
713static int
714__ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
715 unsigned long addr)
716{
717 struct ppc_inst op;
718 unsigned long ip = rec->ip;
719 unsigned long entry, ptr, tramp;
720 struct module *mod = rec->arch.mod;
721
722 /* If we never set up ftrace trampolines, then bail */
723 if (!mod->arch.tramp || !mod->arch.tramp_regs) {
724 pr_err("No ftrace trampoline\n");
725 return -EINVAL;
726 }
727
728 /* read where this goes */
729 if (probe_kernel_read_inst(&op, (void *)ip)) {
730 pr_err("Fetching opcode failed.\n");
731 return -EFAULT;
732 }
733
734 /* Make sure that that this is still a 24bit jump */
735 if (!is_bl_op(op)) {
736 pr_err("Not expected bl: opcode is %s\n", ppc_inst_as_str(op));
737 return -EINVAL;
738 }
739
740 /* lets find where the pointer goes */
741 tramp = find_bl_target(ip, op);
742 entry = ppc_global_function_entry((void *)old_addr);
743
744 pr_devel("ip:%lx jumps to %lx", ip, tramp);
745
746 if (tramp != entry) {
747 /* old_addr is not within range, so we must have used a trampoline */
748 if (module_trampoline_target(mod, tramp, &ptr)) {
749 pr_err("Failed to get trampoline target\n");
750 return -EFAULT;
751 }
752
753 pr_devel("trampoline target %lx", ptr);
754
755 /* This should match what was called */
756 if (ptr != entry) {
757 pr_err("addr %lx does not match expected %lx\n", ptr, entry);
758 return -EINVAL;
759 }
760 }
761
762 /* The new target may be within range */
763 if (test_24bit_addr(ip, addr)) {
764 /* within range */
765 if (patch_branch((struct ppc_inst *)ip, addr, BRANCH_SET_LINK)) {
766 pr_err("REL24 out of range!\n");
767 return -EINVAL;
768 }
769
770 return 0;
771 }
772
773 if (rec->flags & FTRACE_FL_REGS)
774 tramp = mod->arch.tramp_regs;
775 else
776 tramp = mod->arch.tramp;
777
778 if (module_trampoline_target(mod, tramp, &ptr)) {
779 pr_err("Failed to get trampoline target\n");
780 return -EFAULT;
781 }
782
783 pr_devel("trampoline target %lx", ptr);
784
785 entry = ppc_global_function_entry((void *)addr);
786 /* This should match what was called */
787 if (ptr != entry) {
788 pr_err("addr %lx does not match expected %lx\n", ptr, entry);
789 return -EINVAL;
790 }
791
792 /* Ensure branch is within 24 bits */
793 if (create_branch(&op, (struct ppc_inst *)ip, tramp, BRANCH_SET_LINK)) {
794 pr_err("Branch out of range\n");
795 return -EINVAL;
796 }
797
798 if (patch_branch((struct ppc_inst *)ip, tramp, BRANCH_SET_LINK)) {
799 pr_err("REL24 out of range!\n");
800 return -EINVAL;
801 }
802
803 return 0;
804}
805#endif
806
807int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
808 unsigned long addr)
809{
810 unsigned long ip = rec->ip;
811 struct ppc_inst old, new;
812
813 /*
814 * If the calling address is more that 24 bits away,
815 * then we had to use a trampoline to make the call.
816 * Otherwise just update the call site.
817 */
818 if (test_24bit_addr(ip, addr) && test_24bit_addr(ip, old_addr)) {
819 /* within range */
820 old = ftrace_call_replace(ip, old_addr, 1);
821 new = ftrace_call_replace(ip, addr, 1);
822 return ftrace_modify_code(ip, old, new);
823 } else if (core_kernel_text(ip)) {
824 /*
825 * We always patch out of range locations to go to the regs
826 * variant, so there is nothing to do here
827 */
828 return 0;
829 }
830
831#ifdef CONFIG_MODULES
832 /*
833 * Out of range jumps are called from modules.
834 */
835 if (!rec->arch.mod) {
836 pr_err("No module loaded\n");
837 return -EINVAL;
838 }
839
840 return __ftrace_modify_call(rec, old_addr, addr);
841#else
842 /* We should not get here without modules */
843 return -EINVAL;
844#endif /* CONFIG_MODULES */
845}
846#endif
847
848int ftrace_update_ftrace_func(ftrace_func_t func)
849{
850 unsigned long ip = (unsigned long)(&ftrace_call);
851 struct ppc_inst old, new;
852 int ret;
853
854 old = ppc_inst_read((struct ppc_inst *)&ftrace_call);
855 new = ftrace_call_replace(ip, (unsigned long)func, 1);
856 ret = ftrace_modify_code(ip, old, new);
857
858#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
859 /* Also update the regs callback function */
860 if (!ret) {
861 ip = (unsigned long)(&ftrace_regs_call);
862 old = ppc_inst_read((struct ppc_inst *)&ftrace_regs_call);
863 new = ftrace_call_replace(ip, (unsigned long)func, 1);
864 ret = ftrace_modify_code(ip, old, new);
865 }
866#endif
867
868 return ret;
869}
870
871/*
872 * Use the default ftrace_modify_all_code, but without
873 * stop_machine().
874 */
875void arch_ftrace_update_code(int command)
876{
877 ftrace_modify_all_code(command);
878}
879
880#ifdef CONFIG_PPC64
881#define PACATOC offsetof(struct paca_struct, kernel_toc)
882
883extern unsigned int ftrace_tramp_text[], ftrace_tramp_init[];
884
885int __init ftrace_dyn_arch_init(void)
886{
887 int i;
888 unsigned int *tramp[] = { ftrace_tramp_text, ftrace_tramp_init };
889 u32 stub_insns[] = {
890 0xe98d0000 | PACATOC, /* ld r12,PACATOC(r13) */
891 0x3d8c0000, /* addis r12,r12,<high> */
892 0x398c0000, /* addi r12,r12,<low> */
893 0x7d8903a6, /* mtctr r12 */
894 0x4e800420, /* bctr */
895 };
896#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
897 unsigned long addr = ppc_global_function_entry((void *)ftrace_regs_caller);
898#else
899 unsigned long addr = ppc_global_function_entry((void *)ftrace_caller);
900#endif
901 long reladdr = addr - kernel_toc_addr();
902
903 if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
904 pr_err("Address of %ps out of range of kernel_toc.\n",
905 (void *)addr);
906 return -1;
907 }
908
909 for (i = 0; i < 2; i++) {
910 memcpy(tramp[i], stub_insns, sizeof(stub_insns));
911 tramp[i][1] |= PPC_HA(reladdr);
912 tramp[i][2] |= PPC_LO(reladdr);
913 add_ftrace_tramp((unsigned long)tramp[i]);
914 }
915
916 return 0;
917}
918#else
919int __init ftrace_dyn_arch_init(void)
920{
921 return 0;
922}
923#endif
924#endif /* CONFIG_DYNAMIC_FTRACE */
925
926#ifdef CONFIG_FUNCTION_GRAPH_TRACER
927
928extern void ftrace_graph_call(void);
929extern void ftrace_graph_stub(void);
930
931int ftrace_enable_ftrace_graph_caller(void)
932{
933 unsigned long ip = (unsigned long)(&ftrace_graph_call);
934 unsigned long addr = (unsigned long)(&ftrace_graph_caller);
935 unsigned long stub = (unsigned long)(&ftrace_graph_stub);
936 struct ppc_inst old, new;
937
938 old = ftrace_call_replace(ip, stub, 0);
939 new = ftrace_call_replace(ip, addr, 0);
940
941 return ftrace_modify_code(ip, old, new);
942}
943
944int ftrace_disable_ftrace_graph_caller(void)
945{
946 unsigned long ip = (unsigned long)(&ftrace_graph_call);
947 unsigned long addr = (unsigned long)(&ftrace_graph_caller);
948 unsigned long stub = (unsigned long)(&ftrace_graph_stub);
949 struct ppc_inst old, new;
950
951 old = ftrace_call_replace(ip, addr, 0);
952 new = ftrace_call_replace(ip, stub, 0);
953
954 return ftrace_modify_code(ip, old, new);
955}
956
957/*
958 * Hook the return address and push it in the stack of return addrs
959 * in current thread info. Return the address we want to divert to.
960 */
961unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip,
962 unsigned long sp)
963{
964 unsigned long return_hooker;
965
966 if (unlikely(ftrace_graph_is_dead()))
967 goto out;
968
969 if (unlikely(atomic_read(¤t->tracing_graph_pause)))
970 goto out;
971
972 return_hooker = ppc_function_entry(return_to_handler);
973
974 if (!function_graph_enter(parent, ip, 0, (unsigned long *)sp))
975 parent = return_hooker;
976out:
977 return parent;
978}
979#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
980
981#ifdef PPC64_ELF_ABI_v1
982char *arch_ftrace_match_adjust(char *str, const char *search)
983{
984 if (str[0] == '.' && search[0] != '.')
985 return str + 1;
986 else
987 return str;
988}
989#endif /* PPC64_ELF_ABI_v1 */