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Steven Rostedt4e491d12008-05-14 23:49:44 -04001/*
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 *
8 */
9
10#include <linux/spinlock.h>
11#include <linux/hardirq.h>
Steven Rostedte4486fe2008-11-14 16:21:20 -080012#include <linux/uaccess.h>
Steven Rostedtf48cb8b2008-11-14 20:47:03 -080013#include <linux/module.h>
Steven Rostedt4e491d12008-05-14 23:49:44 -040014#include <linux/ftrace.h>
15#include <linux/percpu.h>
16#include <linux/init.h>
17#include <linux/list.h>
18
19#include <asm/cacheflush.h>
Steven Rostedtf48cb8b2008-11-14 20:47:03 -080020#include <asm/code-patching.h>
Abhishek Sagar395a59d2008-06-21 23:47:27 +053021#include <asm/ftrace.h>
Steven Rostedt4e491d12008-05-14 23:49:44 -040022
Steven Rostedtf48cb8b2008-11-14 20:47:03 -080023#if 0
24#define DEBUGP printk
25#else
26#define DEBUGP(fmt , ...) do { } while (0)
27#endif
Steven Rostedt4e491d12008-05-14 23:49:44 -040028
Steven Rostedtf48cb8b2008-11-14 20:47:03 -080029static unsigned int ftrace_nop = PPC_NOP_INSTR;
Steven Rostedt4e491d12008-05-14 23:49:44 -040030
31#ifdef CONFIG_PPC32
32# define GET_ADDR(addr) addr
33#else
34/* PowerPC64's functions are data that points to the functions */
Steven Rostedtf48cb8b2008-11-14 20:47:03 -080035# define GET_ADDR(addr) (*(unsigned long *)addr)
Steven Rostedt4e491d12008-05-14 23:49:44 -040036#endif
37
Abhishek Sagar395a59d2008-06-21 23:47:27 +053038
Steven Rostedt15adc042008-10-23 09:33:08 -040039static unsigned int ftrace_calc_offset(long ip, long addr)
Steven Rostedt4e491d12008-05-14 23:49:44 -040040{
Abhishek Sagar395a59d2008-06-21 23:47:27 +053041 return (int)(addr - ip);
Steven Rostedt4e491d12008-05-14 23:49:44 -040042}
43
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -080044static unsigned char *ftrace_nop_replace(void)
Steven Rostedt4e491d12008-05-14 23:49:44 -040045{
46 return (char *)&ftrace_nop;
47}
48
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -080049static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
Steven Rostedt4e491d12008-05-14 23:49:44 -040050{
51 static unsigned int op;
52
Steven Rostedtccbfac22008-05-22 14:31:07 -040053 /*
54 * It would be nice to just use create_function_call, but that will
55 * update the code itself. Here we need to just return the
56 * instruction that is going to be modified, without modifying the
57 * code.
58 */
Steven Rostedt4e491d12008-05-14 23:49:44 -040059 addr = GET_ADDR(addr);
60
61 /* Set to "bl addr" */
Steven Rostedtccbfac22008-05-22 14:31:07 -040062 op = 0x48000001 | (ftrace_calc_offset(ip, addr) & 0x03fffffc);
Steven Rostedt4e491d12008-05-14 23:49:44 -040063
64 /*
65 * No locking needed, this must be called via kstop_machine
66 * which in essence is like running on a uniprocessor machine.
67 */
68 return (unsigned char *)&op;
69}
70
71#ifdef CONFIG_PPC64
72# define _ASM_ALIGN " .align 3 "
73# define _ASM_PTR " .llong "
74#else
75# define _ASM_ALIGN " .align 2 "
76# define _ASM_PTR " .long "
77#endif
78
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -080079static int
Steven Rostedt4e491d12008-05-14 23:49:44 -040080ftrace_modify_code(unsigned long ip, unsigned char *old_code,
81 unsigned char *new_code)
82{
Steven Rostedte4486fe2008-11-14 16:21:20 -080083 unsigned char replaced[MCOUNT_INSN_SIZE];
Steven Rostedt4e491d12008-05-14 23:49:44 -040084
Steven Rostedt4e491d12008-05-14 23:49:44 -040085 /*
86 * Note: Due to modules and __init, code can
87 * disappear and change, we need to protect against faulting
Steven Rostedte4486fe2008-11-14 16:21:20 -080088 * as well as code changing. We do this by using the
89 * probe_kernel_* functions.
Steven Rostedt4e491d12008-05-14 23:49:44 -040090 *
91 * No real locking needed, this code is run through
Steven Rostedte4486fe2008-11-14 16:21:20 -080092 * kstop_machine, or before SMP starts.
Steven Rostedt4e491d12008-05-14 23:49:44 -040093 */
Steven Rostedt4e491d12008-05-14 23:49:44 -040094
Steven Rostedte4486fe2008-11-14 16:21:20 -080095 /* read the text we want to modify */
96 if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
97 return -EFAULT;
Steven Rostedt4e491d12008-05-14 23:49:44 -040098
Steven Rostedte4486fe2008-11-14 16:21:20 -080099 /* Make sure it is what we expect it to be */
100 if (memcmp(replaced, old_code, MCOUNT_INSN_SIZE) != 0)
101 return -EINVAL;
Steven Rostedt4e491d12008-05-14 23:49:44 -0400102
Steven Rostedte4486fe2008-11-14 16:21:20 -0800103 /* replace the text with the new text */
104 if (probe_kernel_write((void *)ip, new_code, MCOUNT_INSN_SIZE))
105 return -EPERM;
106
107 flush_icache_range(ip, ip + 8);
108
109 return 0;
Steven Rostedt4e491d12008-05-14 23:49:44 -0400110}
111
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800112/*
113 * Helper functions that are the same for both PPC64 and PPC32.
114 */
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -0800115static int test_24bit_addr(unsigned long ip, unsigned long addr)
116{
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -0800117
Steven Rostedt0029ff82008-11-25 14:06:19 -0800118 /* use the create_branch to verify that this offset can be branched */
119 return create_branch((unsigned int *)ip, addr, 0);
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -0800120}
121
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800122static int is_bl_op(unsigned int op)
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -0800123{
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800124 return (op & 0xfc000003) == 0x48000001;
125}
126
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800127static unsigned long find_bl_target(unsigned long ip, unsigned int op)
128{
129 static int offset;
130
131 offset = (op & 0x03fffffc);
132 /* make it signed */
133 if (offset & 0x02000000)
134 offset |= 0xfe000000;
135
136 return ip + (long)offset;
137}
138
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800139#ifdef CONFIG_PPC64
140static int
141__ftrace_make_nop(struct module *mod,
142 struct dyn_ftrace *rec, unsigned long addr)
143{
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800144 unsigned int op;
145 unsigned int jmp[5];
146 unsigned long ptr;
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800147 unsigned long ip = rec->ip;
148 unsigned long tramp;
149 int offset;
150
151 /* read where this goes */
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800152 if (probe_kernel_read(&op, (void *)ip, sizeof(int)))
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800153 return -EFAULT;
154
155 /* Make sure that that this is still a 24bit jump */
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800156 if (!is_bl_op(op)) {
157 printk(KERN_ERR "Not expected bl: opcode is %x\n", op);
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800158 return -EINVAL;
159 }
160
161 /* lets find where the pointer goes */
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800162 tramp = find_bl_target(ip, op);
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -0800163
164 /*
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800165 * On PPC64 the trampoline looks like:
166 * 0x3d, 0x82, 0x00, 0x00, addis r12,r2, <high>
167 * 0x39, 0x8c, 0x00, 0x00, addi r12,r12, <low>
168 * Where the bytes 2,3,6 and 7 make up the 32bit offset
169 * to the TOC that holds the pointer.
170 * to jump to.
171 * 0xf8, 0x41, 0x00, 0x28, std r2,40(r1)
172 * 0xe9, 0x6c, 0x00, 0x20, ld r11,32(r12)
173 * The actually address is 32 bytes from the offset
174 * into the TOC.
175 * 0xe8, 0x4c, 0x00, 0x28, ld r2,40(r12)
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -0800176 */
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800177
178 DEBUGP("ip:%lx jumps to %lx r2: %lx", ip, tramp, mod->arch.toc);
179
180 /* Find where the trampoline jumps to */
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800181 if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) {
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800182 printk(KERN_ERR "Failed to read %lx\n", tramp);
183 return -EFAULT;
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -0800184 }
185
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800186 DEBUGP(" %08x %08x", jmp[0], jmp[1]);
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800187
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800188 /* verify that this is what we expect it to be */
189 if (((jmp[0] & 0xffff0000) != 0x3d820000) ||
190 ((jmp[1] & 0xffff0000) != 0x398c0000) ||
191 (jmp[2] != 0xf8410028) ||
192 (jmp[3] != 0xe96c0020) ||
193 (jmp[4] != 0xe84c0028)) {
194 printk(KERN_ERR "Not a trampoline\n");
195 return -EINVAL;
196 }
197
Steven Rostedtf25f9072009-02-07 20:22:40 +0000198 /* The bottom half is signed extended */
199 offset = ((unsigned)((unsigned short)jmp[0]) << 16) +
200 (int)((short)jmp[1]);
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800201
202 DEBUGP(" %x ", offset);
203
204 /* get the address this jumps too */
205 tramp = mod->arch.toc + offset + 32;
206 DEBUGP("toc: %lx", tramp);
207
208 if (probe_kernel_read(jmp, (void *)tramp, 8)) {
209 printk(KERN_ERR "Failed to read %lx\n", tramp);
210 return -EFAULT;
211 }
212
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800213 DEBUGP(" %08x %08x\n", jmp[0], jmp[1]);
214
215 ptr = ((unsigned long)jmp[0] << 32) + jmp[1];
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800216
217 /* This should match what was called */
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800218 if (ptr != GET_ADDR(addr)) {
219 printk(KERN_ERR "addr does not match %lx\n", ptr);
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800220 return -EINVAL;
221 }
222
223 /*
224 * We want to nop the line, but the next line is
225 * 0xe8, 0x41, 0x00, 0x28 ld r2,40(r1)
226 * This needs to be turned to a nop too.
227 */
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800228 if (probe_kernel_read(&op, (void *)(ip+4), MCOUNT_INSN_SIZE))
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800229 return -EFAULT;
230
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800231 if (op != 0xe8410028) {
232 printk(KERN_ERR "Next line is not ld! (%08x)\n", op);
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800233 return -EINVAL;
234 }
235
236 /*
237 * Milton Miller pointed out that we can not blindly do nops.
238 * If a task was preempted when calling a trace function,
239 * the nops will remove the way to restore the TOC in r2
240 * and the r2 TOC will get corrupted.
241 */
242
243 /*
244 * Replace:
245 * bl <tramp> <==== will be replaced with "b 1f"
246 * ld r2,40(r1)
247 * 1:
248 */
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800249 op = 0x48000008; /* b +8 */
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800250
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800251 if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800252 return -EPERM;
253
Steven Rostedtec682ce2008-11-25 10:22:48 -0800254
255 flush_icache_range(ip, ip + 8);
256
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -0800257 return 0;
258}
259
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800260#else /* !PPC64 */
261static int
262__ftrace_make_nop(struct module *mod,
263 struct dyn_ftrace *rec, unsigned long addr)
264{
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800265 unsigned int op;
266 unsigned int jmp[4];
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500267 unsigned long ip = rec->ip;
268 unsigned long tramp;
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500269
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800270 if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE))
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500271 return -EFAULT;
272
273 /* Make sure that that this is still a 24bit jump */
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800274 if (!is_bl_op(op)) {
275 printk(KERN_ERR "Not expected bl: opcode is %x\n", op);
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500276 return -EINVAL;
277 }
278
279 /* lets find where the pointer goes */
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800280 tramp = find_bl_target(ip, op);
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500281
282 /*
283 * On PPC32 the trampoline looks like:
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800284 * 0x3d, 0x60, 0x00, 0x00 lis r11,sym@ha
285 * 0x39, 0x6b, 0x00, 0x00 addi r11,r11,sym@l
286 * 0x7d, 0x69, 0x03, 0xa6 mtctr r11
287 * 0x4e, 0x80, 0x04, 0x20 bctr
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500288 */
289
290 DEBUGP("ip:%lx jumps to %lx", ip, tramp);
291
292 /* Find where the trampoline jumps to */
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800293 if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) {
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500294 printk(KERN_ERR "Failed to read %lx\n", tramp);
295 return -EFAULT;
296 }
297
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800298 DEBUGP(" %08x %08x ", jmp[0], jmp[1]);
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500299
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800300 /* verify that this is what we expect it to be */
301 if (((jmp[0] & 0xffff0000) != 0x3d600000) ||
302 ((jmp[1] & 0xffff0000) != 0x396b0000) ||
303 (jmp[2] != 0x7d6903a6) ||
304 (jmp[3] != 0x4e800420)) {
305 printk(KERN_ERR "Not a trampoline\n");
306 return -EINVAL;
307 }
308
309 tramp = (jmp[1] & 0xffff) |
310 ((jmp[0] & 0xffff) << 16);
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500311 if (tramp & 0x8000)
312 tramp -= 0x10000;
313
314 DEBUGP(" %x ", tramp);
315
316 if (tramp != addr) {
317 printk(KERN_ERR
318 "Trampoline location %08lx does not match addr\n",
319 tramp);
320 return -EINVAL;
321 }
322
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800323 op = PPC_NOP_INSTR;
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500324
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800325 if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500326 return -EPERM;
327
Steven Rostedtec682ce2008-11-25 10:22:48 -0800328 flush_icache_range(ip, ip + 8);
329
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800330 return 0;
331}
332#endif /* PPC64 */
333
334int ftrace_make_nop(struct module *mod,
335 struct dyn_ftrace *rec, unsigned long addr)
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -0800336{
337 unsigned char *old, *new;
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800338 unsigned long ip = rec->ip;
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -0800339
340 /*
341 * If the calling address is more that 24 bits away,
342 * then we had to use a trampoline to make the call.
343 * Otherwise just update the call site.
344 */
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800345 if (test_24bit_addr(ip, addr)) {
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -0800346 /* within range */
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800347 old = ftrace_call_replace(ip, addr);
348 new = ftrace_nop_replace();
349 return ftrace_modify_code(ip, old, new);
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -0800350 }
351
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800352 /*
353 * Out of range jumps are called from modules.
354 * We should either already have a pointer to the module
355 * or it has been passed in.
356 */
357 if (!rec->arch.mod) {
358 if (!mod) {
359 printk(KERN_ERR "No module loaded addr=%lx\n",
360 addr);
361 return -EFAULT;
362 }
363 rec->arch.mod = mod;
364 } else if (mod) {
365 if (mod != rec->arch.mod) {
366 printk(KERN_ERR
367 "Record mod %p not equal to passed in mod %p\n",
368 rec->arch.mod, mod);
369 return -EINVAL;
370 }
371 /* nothing to do if mod == rec->arch.mod */
372 } else
373 mod = rec->arch.mod;
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800374
375 return __ftrace_make_nop(mod, rec, addr);
376
377}
378
379#ifdef CONFIG_PPC64
380static int
381__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
382{
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800383 unsigned int op[2];
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800384 unsigned long ip = rec->ip;
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800385
386 /* read where this goes */
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800387 if (probe_kernel_read(op, (void *)ip, MCOUNT_INSN_SIZE * 2))
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800388 return -EFAULT;
389
390 /*
391 * It should be pointing to two nops or
392 * b +8; ld r2,40(r1)
393 */
394 if (((op[0] != 0x48000008) || (op[1] != 0xe8410028)) &&
395 ((op[0] != PPC_NOP_INSTR) || (op[1] != PPC_NOP_INSTR))) {
396 printk(KERN_ERR "Expected NOPs but have %x %x\n", op[0], op[1]);
397 return -EINVAL;
398 }
399
400 /* If we never set up a trampoline to ftrace_caller, then bail */
401 if (!rec->arch.mod->arch.tramp) {
402 printk(KERN_ERR "No ftrace trampoline\n");
403 return -EINVAL;
404 }
405
Steven Rostedt0029ff82008-11-25 14:06:19 -0800406 /* create the branch to the trampoline */
407 op[0] = create_branch((unsigned int *)ip,
408 rec->arch.mod->arch.tramp, BRANCH_SET_LINK);
409 if (!op[0]) {
410 printk(KERN_ERR "REL24 out of range!\n");
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800411 return -EINVAL;
412 }
413
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800414 /* ld r2,40(r1) */
415 op[1] = 0xe8410028;
416
417 DEBUGP("write to %lx\n", rec->ip);
418
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800419 if (probe_kernel_write((void *)ip, op, MCOUNT_INSN_SIZE * 2))
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800420 return -EPERM;
421
Steven Rostedtec682ce2008-11-25 10:22:48 -0800422 flush_icache_range(ip, ip + 8);
423
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -0800424 return 0;
425}
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800426#else
427static int
428__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
429{
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800430 unsigned int op;
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500431 unsigned long ip = rec->ip;
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500432
433 /* read where this goes */
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800434 if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE))
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500435 return -EFAULT;
436
437 /* It should be pointing to a nop */
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800438 if (op != PPC_NOP_INSTR) {
439 printk(KERN_ERR "Expected NOP but have %x\n", op);
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500440 return -EINVAL;
441 }
442
443 /* If we never set up a trampoline to ftrace_caller, then bail */
444 if (!rec->arch.mod->arch.tramp) {
445 printk(KERN_ERR "No ftrace trampoline\n");
446 return -EINVAL;
447 }
448
Steven Rostedt0029ff82008-11-25 14:06:19 -0800449 /* create the branch to the trampoline */
450 op = create_branch((unsigned int *)ip,
451 rec->arch.mod->arch.tramp, BRANCH_SET_LINK);
452 if (!op) {
453 printk(KERN_ERR "REL24 out of range!\n");
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500454 return -EINVAL;
455 }
456
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500457 DEBUGP("write to %lx\n", rec->ip);
458
Steven Rostedtd9af12b72008-11-25 06:39:18 -0800459 if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
Steven Rostedt7cc45e62008-11-15 02:39:05 -0500460 return -EPERM;
461
Steven Rostedtec682ce2008-11-25 10:22:48 -0800462 flush_icache_range(ip, ip + 8);
463
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800464 return 0;
465}
466#endif /* CONFIG_PPC64 */
467
468int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
469{
470 unsigned char *old, *new;
471 unsigned long ip = rec->ip;
472
473 /*
474 * If the calling address is more that 24 bits away,
475 * then we had to use a trampoline to make the call.
476 * Otherwise just update the call site.
477 */
478 if (test_24bit_addr(ip, addr)) {
479 /* within range */
480 old = ftrace_nop_replace();
481 new = ftrace_call_replace(ip, addr);
482 return ftrace_modify_code(ip, old, new);
483 }
484
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800485 /*
486 * Out of range jumps are called from modules.
487 * Being that we are converting from nop, it had better
488 * already have a module defined.
489 */
490 if (!rec->arch.mod) {
491 printk(KERN_ERR "No module loaded\n");
492 return -EINVAL;
493 }
Steven Rostedtf48cb8b2008-11-14 20:47:03 -0800494
495 return __ftrace_make_call(rec, addr);
496}
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -0800497
Steven Rostedt15adc042008-10-23 09:33:08 -0400498int ftrace_update_ftrace_func(ftrace_func_t func)
Steven Rostedt4e491d12008-05-14 23:49:44 -0400499{
500 unsigned long ip = (unsigned long)(&ftrace_call);
Abhishek Sagar395a59d2008-06-21 23:47:27 +0530501 unsigned char old[MCOUNT_INSN_SIZE], *new;
Steven Rostedt4e491d12008-05-14 23:49:44 -0400502 int ret;
503
Abhishek Sagar395a59d2008-06-21 23:47:27 +0530504 memcpy(old, &ftrace_call, MCOUNT_INSN_SIZE);
Steven Rostedt4e491d12008-05-14 23:49:44 -0400505 new = ftrace_call_replace(ip, (unsigned long)func);
506 ret = ftrace_modify_code(ip, old, new);
507
508 return ret;
509}
510
Steven Rostedt4e491d12008-05-14 23:49:44 -0400511int __init ftrace_dyn_arch_init(void *data)
512{
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -0800513 /* caller expects data to be zero */
514 unsigned long *p = data;
Steven Rostedt4e491d12008-05-14 23:49:44 -0400515
Steven Rostedt8fd6e5a2008-11-14 16:21:19 -0800516 *p = 0;
Steven Rostedt4e491d12008-05-14 23:49:44 -0400517
518 return 0;
519}