xref: /linux/arch/powerpc/lib/feature-fixups.c (revision a1ea0ca8a6f17d7b79bbc4d05dd4e6ca162d8f15)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Copyright (C) 2001 Ben. Herrenschmidt (benh@kernel.crashing.org)
4  *
5  *  Modifications for ppc64:
6  *      Copyright (C) 2003 Dave Engebretsen <engebret@us.ibm.com>
7  *
8  *  Copyright 2008 Michael Ellerman, IBM Corporation.
9  */
10 
11 #include <linux/types.h>
12 #include <linux/jump_label.h>
13 #include <linux/kernel.h>
14 #include <linux/string.h>
15 #include <linux/init.h>
16 #include <linux/sched/mm.h>
17 #include <linux/stop_machine.h>
18 #include <asm/cputable.h>
19 #include <asm/code-patching.h>
20 #include <asm/page.h>
21 #include <asm/sections.h>
22 #include <asm/setup.h>
23 #include <asm/security_features.h>
24 #include <asm/firmware.h>
25 #include <asm/inst.h>
26 
27 struct fixup_entry {
28 	unsigned long	mask;
29 	unsigned long	value;
30 	long		start_off;
31 	long		end_off;
32 	long		alt_start_off;
33 	long		alt_end_off;
34 };
35 
36 static u32 *calc_addr(struct fixup_entry *fcur, long offset)
37 {
38 	/*
39 	 * We store the offset to the code as a negative offset from
40 	 * the start of the alt_entry, to support the VDSO. This
41 	 * routine converts that back into an actual address.
42 	 */
43 	return (u32 *)((unsigned long)fcur + offset);
44 }
45 
46 static int patch_alt_instruction(u32 *src, u32 *dest, u32 *alt_start, u32 *alt_end)
47 {
48 	int err;
49 	struct ppc_inst instr;
50 
51 	instr = ppc_inst_read(src);
52 
53 	if (instr_is_relative_branch(ppc_inst_read(src))) {
54 		u32 *target = (u32 *)branch_target(src);
55 
56 		/* Branch within the section doesn't need translating */
57 		if (target < alt_start || target > alt_end) {
58 			err = translate_branch(&instr, dest, src);
59 			if (err)
60 				return 1;
61 		}
62 	}
63 
64 	raw_patch_instruction(dest, instr);
65 
66 	return 0;
67 }
68 
69 static int patch_feature_section(unsigned long value, struct fixup_entry *fcur)
70 {
71 	u32 *start, *end, *alt_start, *alt_end, *src, *dest;
72 
73 	start = calc_addr(fcur, fcur->start_off);
74 	end = calc_addr(fcur, fcur->end_off);
75 	alt_start = calc_addr(fcur, fcur->alt_start_off);
76 	alt_end = calc_addr(fcur, fcur->alt_end_off);
77 
78 	if ((alt_end - alt_start) > (end - start))
79 		return 1;
80 
81 	if ((value & fcur->mask) == fcur->value)
82 		return 0;
83 
84 	src = alt_start;
85 	dest = start;
86 
87 	for (; src < alt_end; src = ppc_inst_next(src, src),
88 			      dest = ppc_inst_next(dest, dest)) {
89 		if (patch_alt_instruction(src, dest, alt_start, alt_end))
90 			return 1;
91 	}
92 
93 	for (; dest < end; dest++)
94 		raw_patch_instruction(dest, ppc_inst(PPC_RAW_NOP()));
95 
96 	return 0;
97 }
98 
99 void do_feature_fixups(unsigned long value, void *fixup_start, void *fixup_end)
100 {
101 	struct fixup_entry *fcur, *fend;
102 
103 	fcur = fixup_start;
104 	fend = fixup_end;
105 
106 	for (; fcur < fend; fcur++) {
107 		if (patch_feature_section(value, fcur)) {
108 			WARN_ON(1);
109 			printk("Unable to patch feature section at %p - %p" \
110 				" with %p - %p\n",
111 				calc_addr(fcur, fcur->start_off),
112 				calc_addr(fcur, fcur->end_off),
113 				calc_addr(fcur, fcur->alt_start_off),
114 				calc_addr(fcur, fcur->alt_end_off));
115 		}
116 	}
117 }
118 
119 #ifdef CONFIG_PPC_BOOK3S_64
120 static void do_stf_entry_barrier_fixups(enum stf_barrier_type types)
121 {
122 	unsigned int instrs[3], *dest;
123 	long *start, *end;
124 	int i;
125 
126 	start = PTRRELOC(&__start___stf_entry_barrier_fixup);
127 	end = PTRRELOC(&__stop___stf_entry_barrier_fixup);
128 
129 	instrs[0] = PPC_RAW_NOP();
130 	instrs[1] = PPC_RAW_NOP();
131 	instrs[2] = PPC_RAW_NOP();
132 
133 	i = 0;
134 	if (types & STF_BARRIER_FALLBACK) {
135 		instrs[i++] = PPC_RAW_MFLR(_R10);
136 		instrs[i++] = PPC_RAW_NOP(); /* branch patched below */
137 		instrs[i++] = PPC_RAW_MTLR(_R10);
138 	} else if (types & STF_BARRIER_EIEIO) {
139 		instrs[i++] = PPC_RAW_EIEIO() | 0x02000000; /* eieio + bit 6 hint */
140 	} else if (types & STF_BARRIER_SYNC_ORI) {
141 		instrs[i++] = PPC_RAW_SYNC();
142 		instrs[i++] = PPC_RAW_LD(_R10, _R13, 0);
143 		instrs[i++] = PPC_RAW_ORI(_R31, _R31, 0); /* speculation barrier */
144 	}
145 
146 	for (i = 0; start < end; start++, i++) {
147 		dest = (void *)start + *start;
148 
149 		pr_devel("patching dest %lx\n", (unsigned long)dest);
150 
151 		// See comment in do_entry_flush_fixups() RE order of patching
152 		if (types & STF_BARRIER_FALLBACK) {
153 			patch_instruction(dest, ppc_inst(instrs[0]));
154 			patch_instruction(dest + 2, ppc_inst(instrs[2]));
155 			patch_branch(dest + 1,
156 				     (unsigned long)&stf_barrier_fallback, BRANCH_SET_LINK);
157 		} else {
158 			patch_instruction(dest + 1, ppc_inst(instrs[1]));
159 			patch_instruction(dest + 2, ppc_inst(instrs[2]));
160 			patch_instruction(dest, ppc_inst(instrs[0]));
161 		}
162 	}
163 
164 	printk(KERN_DEBUG "stf-barrier: patched %d entry locations (%s barrier)\n", i,
165 		(types == STF_BARRIER_NONE)                  ? "no" :
166 		(types == STF_BARRIER_FALLBACK)              ? "fallback" :
167 		(types == STF_BARRIER_EIEIO)                 ? "eieio" :
168 		(types == (STF_BARRIER_SYNC_ORI))            ? "hwsync"
169 		                                           : "unknown");
170 }
171 
172 static void do_stf_exit_barrier_fixups(enum stf_barrier_type types)
173 {
174 	unsigned int instrs[6], *dest;
175 	long *start, *end;
176 	int i;
177 
178 	start = PTRRELOC(&__start___stf_exit_barrier_fixup);
179 	end = PTRRELOC(&__stop___stf_exit_barrier_fixup);
180 
181 	instrs[0] = PPC_RAW_NOP();
182 	instrs[1] = PPC_RAW_NOP();
183 	instrs[2] = PPC_RAW_NOP();
184 	instrs[3] = PPC_RAW_NOP();
185 	instrs[4] = PPC_RAW_NOP();
186 	instrs[5] = PPC_RAW_NOP();
187 
188 	i = 0;
189 	if (types & STF_BARRIER_FALLBACK || types & STF_BARRIER_SYNC_ORI) {
190 		if (cpu_has_feature(CPU_FTR_HVMODE)) {
191 			instrs[i++] = PPC_RAW_MTSPR(SPRN_HSPRG1, _R13);
192 			instrs[i++] = PPC_RAW_MFSPR(_R13, SPRN_HSPRG0);
193 		} else {
194 			instrs[i++] = PPC_RAW_MTSPR(SPRN_SPRG2, _R13);
195 			instrs[i++] = PPC_RAW_MFSPR(_R13, SPRN_SPRG1);
196 	        }
197 		instrs[i++] = PPC_RAW_SYNC();
198 		instrs[i++] = PPC_RAW_LD(_R13, _R13, 0);
199 		instrs[i++] = PPC_RAW_ORI(_R31, _R31, 0); /* speculation barrier */
200 		if (cpu_has_feature(CPU_FTR_HVMODE))
201 			instrs[i++] = PPC_RAW_MFSPR(_R13, SPRN_HSPRG1);
202 		else
203 			instrs[i++] = PPC_RAW_MFSPR(_R13, SPRN_SPRG2);
204 	} else if (types & STF_BARRIER_EIEIO) {
205 		instrs[i++] = PPC_RAW_EIEIO() | 0x02000000; /* eieio + bit 6 hint */
206 	}
207 
208 	for (i = 0; start < end; start++, i++) {
209 		dest = (void *)start + *start;
210 
211 		pr_devel("patching dest %lx\n", (unsigned long)dest);
212 
213 		patch_instruction(dest, ppc_inst(instrs[0]));
214 		patch_instruction(dest + 1, ppc_inst(instrs[1]));
215 		patch_instruction(dest + 2, ppc_inst(instrs[2]));
216 		patch_instruction(dest + 3, ppc_inst(instrs[3]));
217 		patch_instruction(dest + 4, ppc_inst(instrs[4]));
218 		patch_instruction(dest + 5, ppc_inst(instrs[5]));
219 	}
220 	printk(KERN_DEBUG "stf-barrier: patched %d exit locations (%s barrier)\n", i,
221 		(types == STF_BARRIER_NONE)                  ? "no" :
222 		(types == STF_BARRIER_FALLBACK)              ? "fallback" :
223 		(types == STF_BARRIER_EIEIO)                 ? "eieio" :
224 		(types == (STF_BARRIER_SYNC_ORI))            ? "hwsync"
225 		                                           : "unknown");
226 }
227 
228 static int __do_stf_barrier_fixups(void *data)
229 {
230 	enum stf_barrier_type *types = data;
231 
232 	do_stf_entry_barrier_fixups(*types);
233 	do_stf_exit_barrier_fixups(*types);
234 
235 	return 0;
236 }
237 
238 void do_stf_barrier_fixups(enum stf_barrier_type types)
239 {
240 	/*
241 	 * The call to the fallback entry flush, and the fallback/sync-ori exit
242 	 * flush can not be safely patched in/out while other CPUs are executing
243 	 * them. So call __do_stf_barrier_fixups() on one CPU while all other CPUs
244 	 * spin in the stop machine core with interrupts hard disabled.
245 	 */
246 	stop_machine(__do_stf_barrier_fixups, &types, NULL);
247 }
248 
249 void do_uaccess_flush_fixups(enum l1d_flush_type types)
250 {
251 	unsigned int instrs[4], *dest;
252 	long *start, *end;
253 	int i;
254 
255 	start = PTRRELOC(&__start___uaccess_flush_fixup);
256 	end = PTRRELOC(&__stop___uaccess_flush_fixup);
257 
258 	instrs[0] = PPC_RAW_NOP();
259 	instrs[1] = PPC_RAW_NOP();
260 	instrs[2] = PPC_RAW_NOP();
261 	instrs[3] = PPC_RAW_BLR();
262 
263 	i = 0;
264 	if (types == L1D_FLUSH_FALLBACK) {
265 		instrs[3] = PPC_RAW_NOP();
266 		/* fallthrough to fallback flush */
267 	}
268 
269 	if (types & L1D_FLUSH_ORI) {
270 		instrs[i++] = PPC_RAW_ORI(_R31, _R31, 0); /* speculation barrier */
271 		instrs[i++] = PPC_RAW_ORI(_R30, _R30, 0); /* L1d flush */
272 	}
273 
274 	if (types & L1D_FLUSH_MTTRIG)
275 		instrs[i++] = PPC_RAW_MTSPR(SPRN_TRIG2, _R0);
276 
277 	for (i = 0; start < end; start++, i++) {
278 		dest = (void *)start + *start;
279 
280 		pr_devel("patching dest %lx\n", (unsigned long)dest);
281 
282 		patch_instruction(dest, ppc_inst(instrs[0]));
283 
284 		patch_instruction(dest + 1, ppc_inst(instrs[1]));
285 		patch_instruction(dest + 2, ppc_inst(instrs[2]));
286 		patch_instruction(dest + 3, ppc_inst(instrs[3]));
287 	}
288 
289 	printk(KERN_DEBUG "uaccess-flush: patched %d locations (%s flush)\n", i,
290 		(types == L1D_FLUSH_NONE)       ? "no" :
291 		(types == L1D_FLUSH_FALLBACK)   ? "fallback displacement" :
292 		(types &  L1D_FLUSH_ORI)        ? (types & L1D_FLUSH_MTTRIG)
293 							? "ori+mttrig type"
294 							: "ori type" :
295 		(types &  L1D_FLUSH_MTTRIG)     ? "mttrig type"
296 						: "unknown");
297 }
298 
299 static int __do_entry_flush_fixups(void *data)
300 {
301 	enum l1d_flush_type types = *(enum l1d_flush_type *)data;
302 	unsigned int instrs[3], *dest;
303 	long *start, *end;
304 	int i;
305 
306 	instrs[0] = PPC_RAW_NOP();
307 	instrs[1] = PPC_RAW_NOP();
308 	instrs[2] = PPC_RAW_NOP();
309 
310 	i = 0;
311 	if (types == L1D_FLUSH_FALLBACK) {
312 		instrs[i++] = PPC_RAW_MFLR(_R10);
313 		instrs[i++] = PPC_RAW_NOP(); /* branch patched below */
314 		instrs[i++] = PPC_RAW_MTLR(_R10);
315 	}
316 
317 	if (types & L1D_FLUSH_ORI) {
318 		instrs[i++] = PPC_RAW_ORI(_R31, _R31, 0); /* speculation barrier */
319 		instrs[i++] = PPC_RAW_ORI(_R30, _R30, 0); /* L1d flush */
320 	}
321 
322 	if (types & L1D_FLUSH_MTTRIG)
323 		instrs[i++] = PPC_RAW_MTSPR(SPRN_TRIG2, _R0);
324 
325 	/*
326 	 * If we're patching in or out the fallback flush we need to be careful about the
327 	 * order in which we patch instructions. That's because it's possible we could
328 	 * take a page fault after patching one instruction, so the sequence of
329 	 * instructions must be safe even in a half patched state.
330 	 *
331 	 * To make that work, when patching in the fallback flush we patch in this order:
332 	 *  - the mflr		(dest)
333 	 *  - the mtlr		(dest + 2)
334 	 *  - the branch	(dest + 1)
335 	 *
336 	 * That ensures the sequence is safe to execute at any point. In contrast if we
337 	 * patch the mtlr last, it's possible we could return from the branch and not
338 	 * restore LR, leading to a crash later.
339 	 *
340 	 * When patching out the fallback flush (either with nops or another flush type),
341 	 * we patch in this order:
342 	 *  - the branch	(dest + 1)
343 	 *  - the mtlr		(dest + 2)
344 	 *  - the mflr		(dest)
345 	 *
346 	 * Note we are protected by stop_machine() from other CPUs executing the code in a
347 	 * semi-patched state.
348 	 */
349 
350 	start = PTRRELOC(&__start___entry_flush_fixup);
351 	end = PTRRELOC(&__stop___entry_flush_fixup);
352 	for (i = 0; start < end; start++, i++) {
353 		dest = (void *)start + *start;
354 
355 		pr_devel("patching dest %lx\n", (unsigned long)dest);
356 
357 		if (types == L1D_FLUSH_FALLBACK) {
358 			patch_instruction(dest, ppc_inst(instrs[0]));
359 			patch_instruction(dest + 2, ppc_inst(instrs[2]));
360 			patch_branch(dest + 1,
361 				     (unsigned long)&entry_flush_fallback, BRANCH_SET_LINK);
362 		} else {
363 			patch_instruction(dest + 1, ppc_inst(instrs[1]));
364 			patch_instruction(dest + 2, ppc_inst(instrs[2]));
365 			patch_instruction(dest, ppc_inst(instrs[0]));
366 		}
367 	}
368 
369 	start = PTRRELOC(&__start___scv_entry_flush_fixup);
370 	end = PTRRELOC(&__stop___scv_entry_flush_fixup);
371 	for (; start < end; start++, i++) {
372 		dest = (void *)start + *start;
373 
374 		pr_devel("patching dest %lx\n", (unsigned long)dest);
375 
376 		if (types == L1D_FLUSH_FALLBACK) {
377 			patch_instruction(dest, ppc_inst(instrs[0]));
378 			patch_instruction(dest + 2, ppc_inst(instrs[2]));
379 			patch_branch(dest + 1,
380 				     (unsigned long)&scv_entry_flush_fallback, BRANCH_SET_LINK);
381 		} else {
382 			patch_instruction(dest + 1, ppc_inst(instrs[1]));
383 			patch_instruction(dest + 2, ppc_inst(instrs[2]));
384 			patch_instruction(dest, ppc_inst(instrs[0]));
385 		}
386 	}
387 
388 
389 	printk(KERN_DEBUG "entry-flush: patched %d locations (%s flush)\n", i,
390 		(types == L1D_FLUSH_NONE)       ? "no" :
391 		(types == L1D_FLUSH_FALLBACK)   ? "fallback displacement" :
392 		(types &  L1D_FLUSH_ORI)        ? (types & L1D_FLUSH_MTTRIG)
393 							? "ori+mttrig type"
394 							: "ori type" :
395 		(types &  L1D_FLUSH_MTTRIG)     ? "mttrig type"
396 						: "unknown");
397 
398 	return 0;
399 }
400 
401 void do_entry_flush_fixups(enum l1d_flush_type types)
402 {
403 	/*
404 	 * The call to the fallback flush can not be safely patched in/out while
405 	 * other CPUs are executing it. So call __do_entry_flush_fixups() on one
406 	 * CPU while all other CPUs spin in the stop machine core with interrupts
407 	 * hard disabled.
408 	 */
409 	stop_machine(__do_entry_flush_fixups, &types, NULL);
410 }
411 
412 void do_rfi_flush_fixups(enum l1d_flush_type types)
413 {
414 	unsigned int instrs[3], *dest;
415 	long *start, *end;
416 	int i;
417 
418 	start = PTRRELOC(&__start___rfi_flush_fixup);
419 	end = PTRRELOC(&__stop___rfi_flush_fixup);
420 
421 	instrs[0] = PPC_RAW_NOP();
422 	instrs[1] = PPC_RAW_NOP();
423 	instrs[2] = PPC_RAW_NOP();
424 
425 	if (types & L1D_FLUSH_FALLBACK)
426 		/* b .+16 to fallback flush */
427 		instrs[0] = PPC_INST_BRANCH | 16;
428 
429 	i = 0;
430 	if (types & L1D_FLUSH_ORI) {
431 		instrs[i++] = PPC_RAW_ORI(_R31, _R31, 0); /* speculation barrier */
432 		instrs[i++] = PPC_RAW_ORI(_R30, _R30, 0); /* L1d flush */
433 	}
434 
435 	if (types & L1D_FLUSH_MTTRIG)
436 		instrs[i++] = PPC_RAW_MTSPR(SPRN_TRIG2, _R0);
437 
438 	for (i = 0; start < end; start++, i++) {
439 		dest = (void *)start + *start;
440 
441 		pr_devel("patching dest %lx\n", (unsigned long)dest);
442 
443 		patch_instruction(dest, ppc_inst(instrs[0]));
444 		patch_instruction(dest + 1, ppc_inst(instrs[1]));
445 		patch_instruction(dest + 2, ppc_inst(instrs[2]));
446 	}
447 
448 	printk(KERN_DEBUG "rfi-flush: patched %d locations (%s flush)\n", i,
449 		(types == L1D_FLUSH_NONE)       ? "no" :
450 		(types == L1D_FLUSH_FALLBACK)   ? "fallback displacement" :
451 		(types &  L1D_FLUSH_ORI)        ? (types & L1D_FLUSH_MTTRIG)
452 							? "ori+mttrig type"
453 							: "ori type" :
454 		(types &  L1D_FLUSH_MTTRIG)     ? "mttrig type"
455 						: "unknown");
456 }
457 
458 void do_barrier_nospec_fixups_range(bool enable, void *fixup_start, void *fixup_end)
459 {
460 	unsigned int instr, *dest;
461 	long *start, *end;
462 	int i;
463 
464 	start = fixup_start;
465 	end = fixup_end;
466 
467 	instr = PPC_RAW_NOP();
468 
469 	if (enable) {
470 		pr_info("barrier-nospec: using ORI speculation barrier\n");
471 		instr = PPC_RAW_ORI(_R31, _R31, 0); /* speculation barrier */
472 	}
473 
474 	for (i = 0; start < end; start++, i++) {
475 		dest = (void *)start + *start;
476 
477 		pr_devel("patching dest %lx\n", (unsigned long)dest);
478 		patch_instruction(dest, ppc_inst(instr));
479 	}
480 
481 	printk(KERN_DEBUG "barrier-nospec: patched %d locations\n", i);
482 }
483 
484 #endif /* CONFIG_PPC_BOOK3S_64 */
485 
486 #ifdef CONFIG_PPC_BARRIER_NOSPEC
487 void do_barrier_nospec_fixups(bool enable)
488 {
489 	void *start, *end;
490 
491 	start = PTRRELOC(&__start___barrier_nospec_fixup);
492 	end = PTRRELOC(&__stop___barrier_nospec_fixup);
493 
494 	do_barrier_nospec_fixups_range(enable, start, end);
495 }
496 #endif /* CONFIG_PPC_BARRIER_NOSPEC */
497 
498 #ifdef CONFIG_PPC_FSL_BOOK3E
499 void do_barrier_nospec_fixups_range(bool enable, void *fixup_start, void *fixup_end)
500 {
501 	unsigned int instr[2], *dest;
502 	long *start, *end;
503 	int i;
504 
505 	start = fixup_start;
506 	end = fixup_end;
507 
508 	instr[0] = PPC_RAW_NOP();
509 	instr[1] = PPC_RAW_NOP();
510 
511 	if (enable) {
512 		pr_info("barrier-nospec: using isync; sync as speculation barrier\n");
513 		instr[0] = PPC_RAW_ISYNC();
514 		instr[1] = PPC_RAW_SYNC();
515 	}
516 
517 	for (i = 0; start < end; start++, i++) {
518 		dest = (void *)start + *start;
519 
520 		pr_devel("patching dest %lx\n", (unsigned long)dest);
521 		patch_instruction(dest, ppc_inst(instr[0]));
522 		patch_instruction(dest + 1, ppc_inst(instr[1]));
523 	}
524 
525 	printk(KERN_DEBUG "barrier-nospec: patched %d locations\n", i);
526 }
527 
528 static void patch_btb_flush_section(long *curr)
529 {
530 	unsigned int *start, *end;
531 
532 	start = (void *)curr + *curr;
533 	end = (void *)curr + *(curr + 1);
534 	for (; start < end; start++) {
535 		pr_devel("patching dest %lx\n", (unsigned long)start);
536 		patch_instruction(start, ppc_inst(PPC_RAW_NOP()));
537 	}
538 }
539 
540 void do_btb_flush_fixups(void)
541 {
542 	long *start, *end;
543 
544 	start = PTRRELOC(&__start__btb_flush_fixup);
545 	end = PTRRELOC(&__stop__btb_flush_fixup);
546 
547 	for (; start < end; start += 2)
548 		patch_btb_flush_section(start);
549 }
550 #endif /* CONFIG_PPC_FSL_BOOK3E */
551 
552 void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end)
553 {
554 	long *start, *end;
555 	u32 *dest;
556 
557 	if (!(value & CPU_FTR_LWSYNC))
558 		return ;
559 
560 	start = fixup_start;
561 	end = fixup_end;
562 
563 	for (; start < end; start++) {
564 		dest = (void *)start + *start;
565 		raw_patch_instruction(dest, ppc_inst(PPC_INST_LWSYNC));
566 	}
567 }
568 
569 static void do_final_fixups(void)
570 {
571 #if defined(CONFIG_PPC64) && defined(CONFIG_RELOCATABLE)
572 	struct ppc_inst inst;
573 	u32 *src, *dest, *end;
574 
575 	if (PHYSICAL_START == 0)
576 		return;
577 
578 	src = (u32 *)(KERNELBASE + PHYSICAL_START);
579 	dest = (u32 *)KERNELBASE;
580 	end = (void *)src + (__end_interrupts - _stext);
581 
582 	while (src < end) {
583 		inst = ppc_inst_read(src);
584 		raw_patch_instruction(dest, inst);
585 		src = ppc_inst_next(src, src);
586 		dest = ppc_inst_next(dest, dest);
587 	}
588 #endif
589 }
590 
591 static unsigned long __initdata saved_cpu_features;
592 static unsigned int __initdata saved_mmu_features;
593 #ifdef CONFIG_PPC64
594 static unsigned long __initdata saved_firmware_features;
595 #endif
596 
597 void __init apply_feature_fixups(void)
598 {
599 	struct cpu_spec *spec = PTRRELOC(*PTRRELOC(&cur_cpu_spec));
600 
601 	*PTRRELOC(&saved_cpu_features) = spec->cpu_features;
602 	*PTRRELOC(&saved_mmu_features) = spec->mmu_features;
603 
604 	/*
605 	 * Apply the CPU-specific and firmware specific fixups to kernel text
606 	 * (nop out sections not relevant to this CPU or this firmware).
607 	 */
608 	do_feature_fixups(spec->cpu_features,
609 			  PTRRELOC(&__start___ftr_fixup),
610 			  PTRRELOC(&__stop___ftr_fixup));
611 
612 	do_feature_fixups(spec->mmu_features,
613 			  PTRRELOC(&__start___mmu_ftr_fixup),
614 			  PTRRELOC(&__stop___mmu_ftr_fixup));
615 
616 	do_lwsync_fixups(spec->cpu_features,
617 			 PTRRELOC(&__start___lwsync_fixup),
618 			 PTRRELOC(&__stop___lwsync_fixup));
619 
620 #ifdef CONFIG_PPC64
621 	saved_firmware_features = powerpc_firmware_features;
622 	do_feature_fixups(powerpc_firmware_features,
623 			  &__start___fw_ftr_fixup, &__stop___fw_ftr_fixup);
624 #endif
625 	do_final_fixups();
626 }
627 
628 void __init setup_feature_keys(void)
629 {
630 	/*
631 	 * Initialise jump label. This causes all the cpu/mmu_has_feature()
632 	 * checks to take on their correct polarity based on the current set of
633 	 * CPU/MMU features.
634 	 */
635 	jump_label_init();
636 	cpu_feature_keys_init();
637 	mmu_feature_keys_init();
638 }
639 
640 static int __init check_features(void)
641 {
642 	WARN(saved_cpu_features != cur_cpu_spec->cpu_features,
643 	     "CPU features changed after feature patching!\n");
644 	WARN(saved_mmu_features != cur_cpu_spec->mmu_features,
645 	     "MMU features changed after feature patching!\n");
646 #ifdef CONFIG_PPC64
647 	WARN(saved_firmware_features != powerpc_firmware_features,
648 	     "Firmware features changed after feature patching!\n");
649 #endif
650 
651 	return 0;
652 }
653 late_initcall(check_features);
654 
655 #ifdef CONFIG_FTR_FIXUP_SELFTEST
656 
657 #define check(x)	\
658 	if (!(x)) printk("feature-fixups: test failed at line %d\n", __LINE__);
659 
660 /* This must be after the text it fixes up, vmlinux.lds.S enforces that atm */
661 static struct fixup_entry fixup;
662 
663 static long calc_offset(struct fixup_entry *entry, unsigned int *p)
664 {
665 	return (unsigned long)p - (unsigned long)entry;
666 }
667 
668 static void test_basic_patching(void)
669 {
670 	extern unsigned int ftr_fixup_test1[];
671 	extern unsigned int end_ftr_fixup_test1[];
672 	extern unsigned int ftr_fixup_test1_orig[];
673 	extern unsigned int ftr_fixup_test1_expected[];
674 	int size = 4 * (end_ftr_fixup_test1 - ftr_fixup_test1);
675 
676 	fixup.value = fixup.mask = 8;
677 	fixup.start_off = calc_offset(&fixup, ftr_fixup_test1 + 1);
678 	fixup.end_off = calc_offset(&fixup, ftr_fixup_test1 + 2);
679 	fixup.alt_start_off = fixup.alt_end_off = 0;
680 
681 	/* Sanity check */
682 	check(memcmp(ftr_fixup_test1, ftr_fixup_test1_orig, size) == 0);
683 
684 	/* Check we don't patch if the value matches */
685 	patch_feature_section(8, &fixup);
686 	check(memcmp(ftr_fixup_test1, ftr_fixup_test1_orig, size) == 0);
687 
688 	/* Check we do patch if the value doesn't match */
689 	patch_feature_section(0, &fixup);
690 	check(memcmp(ftr_fixup_test1, ftr_fixup_test1_expected, size) == 0);
691 
692 	/* Check we do patch if the mask doesn't match */
693 	memcpy(ftr_fixup_test1, ftr_fixup_test1_orig, size);
694 	check(memcmp(ftr_fixup_test1, ftr_fixup_test1_orig, size) == 0);
695 	patch_feature_section(~8, &fixup);
696 	check(memcmp(ftr_fixup_test1, ftr_fixup_test1_expected, size) == 0);
697 }
698 
699 static void test_alternative_patching(void)
700 {
701 	extern unsigned int ftr_fixup_test2[];
702 	extern unsigned int end_ftr_fixup_test2[];
703 	extern unsigned int ftr_fixup_test2_orig[];
704 	extern unsigned int ftr_fixup_test2_alt[];
705 	extern unsigned int ftr_fixup_test2_expected[];
706 	int size = 4 * (end_ftr_fixup_test2 - ftr_fixup_test2);
707 
708 	fixup.value = fixup.mask = 0xF;
709 	fixup.start_off = calc_offset(&fixup, ftr_fixup_test2 + 1);
710 	fixup.end_off = calc_offset(&fixup, ftr_fixup_test2 + 2);
711 	fixup.alt_start_off = calc_offset(&fixup, ftr_fixup_test2_alt);
712 	fixup.alt_end_off = calc_offset(&fixup, ftr_fixup_test2_alt + 1);
713 
714 	/* Sanity check */
715 	check(memcmp(ftr_fixup_test2, ftr_fixup_test2_orig, size) == 0);
716 
717 	/* Check we don't patch if the value matches */
718 	patch_feature_section(0xF, &fixup);
719 	check(memcmp(ftr_fixup_test2, ftr_fixup_test2_orig, size) == 0);
720 
721 	/* Check we do patch if the value doesn't match */
722 	patch_feature_section(0, &fixup);
723 	check(memcmp(ftr_fixup_test2, ftr_fixup_test2_expected, size) == 0);
724 
725 	/* Check we do patch if the mask doesn't match */
726 	memcpy(ftr_fixup_test2, ftr_fixup_test2_orig, size);
727 	check(memcmp(ftr_fixup_test2, ftr_fixup_test2_orig, size) == 0);
728 	patch_feature_section(~0xF, &fixup);
729 	check(memcmp(ftr_fixup_test2, ftr_fixup_test2_expected, size) == 0);
730 }
731 
732 static void test_alternative_case_too_big(void)
733 {
734 	extern unsigned int ftr_fixup_test3[];
735 	extern unsigned int end_ftr_fixup_test3[];
736 	extern unsigned int ftr_fixup_test3_orig[];
737 	extern unsigned int ftr_fixup_test3_alt[];
738 	int size = 4 * (end_ftr_fixup_test3 - ftr_fixup_test3);
739 
740 	fixup.value = fixup.mask = 0xC;
741 	fixup.start_off = calc_offset(&fixup, ftr_fixup_test3 + 1);
742 	fixup.end_off = calc_offset(&fixup, ftr_fixup_test3 + 2);
743 	fixup.alt_start_off = calc_offset(&fixup, ftr_fixup_test3_alt);
744 	fixup.alt_end_off = calc_offset(&fixup, ftr_fixup_test3_alt + 2);
745 
746 	/* Sanity check */
747 	check(memcmp(ftr_fixup_test3, ftr_fixup_test3_orig, size) == 0);
748 
749 	/* Expect nothing to be patched, and the error returned to us */
750 	check(patch_feature_section(0xF, &fixup) == 1);
751 	check(memcmp(ftr_fixup_test3, ftr_fixup_test3_orig, size) == 0);
752 	check(patch_feature_section(0, &fixup) == 1);
753 	check(memcmp(ftr_fixup_test3, ftr_fixup_test3_orig, size) == 0);
754 	check(patch_feature_section(~0xF, &fixup) == 1);
755 	check(memcmp(ftr_fixup_test3, ftr_fixup_test3_orig, size) == 0);
756 }
757 
758 static void test_alternative_case_too_small(void)
759 {
760 	extern unsigned int ftr_fixup_test4[];
761 	extern unsigned int end_ftr_fixup_test4[];
762 	extern unsigned int ftr_fixup_test4_orig[];
763 	extern unsigned int ftr_fixup_test4_alt[];
764 	extern unsigned int ftr_fixup_test4_expected[];
765 	int size = 4 * (end_ftr_fixup_test4 - ftr_fixup_test4);
766 	unsigned long flag;
767 
768 	/* Check a high-bit flag */
769 	flag = 1UL << ((sizeof(unsigned long) - 1) * 8);
770 	fixup.value = fixup.mask = flag;
771 	fixup.start_off = calc_offset(&fixup, ftr_fixup_test4 + 1);
772 	fixup.end_off = calc_offset(&fixup, ftr_fixup_test4 + 5);
773 	fixup.alt_start_off = calc_offset(&fixup, ftr_fixup_test4_alt);
774 	fixup.alt_end_off = calc_offset(&fixup, ftr_fixup_test4_alt + 2);
775 
776 	/* Sanity check */
777 	check(memcmp(ftr_fixup_test4, ftr_fixup_test4_orig, size) == 0);
778 
779 	/* Check we don't patch if the value matches */
780 	patch_feature_section(flag, &fixup);
781 	check(memcmp(ftr_fixup_test4, ftr_fixup_test4_orig, size) == 0);
782 
783 	/* Check we do patch if the value doesn't match */
784 	patch_feature_section(0, &fixup);
785 	check(memcmp(ftr_fixup_test4, ftr_fixup_test4_expected, size) == 0);
786 
787 	/* Check we do patch if the mask doesn't match */
788 	memcpy(ftr_fixup_test4, ftr_fixup_test4_orig, size);
789 	check(memcmp(ftr_fixup_test4, ftr_fixup_test4_orig, size) == 0);
790 	patch_feature_section(~flag, &fixup);
791 	check(memcmp(ftr_fixup_test4, ftr_fixup_test4_expected, size) == 0);
792 }
793 
794 static void test_alternative_case_with_branch(void)
795 {
796 	extern unsigned int ftr_fixup_test5[];
797 	extern unsigned int end_ftr_fixup_test5[];
798 	extern unsigned int ftr_fixup_test5_expected[];
799 	int size = 4 * (end_ftr_fixup_test5 - ftr_fixup_test5);
800 
801 	check(memcmp(ftr_fixup_test5, ftr_fixup_test5_expected, size) == 0);
802 }
803 
804 static void test_alternative_case_with_external_branch(void)
805 {
806 	extern unsigned int ftr_fixup_test6[];
807 	extern unsigned int end_ftr_fixup_test6[];
808 	extern unsigned int ftr_fixup_test6_expected[];
809 	int size = 4 * (end_ftr_fixup_test6 - ftr_fixup_test6);
810 
811 	check(memcmp(ftr_fixup_test6, ftr_fixup_test6_expected, size) == 0);
812 }
813 
814 static void test_alternative_case_with_branch_to_end(void)
815 {
816 	extern unsigned int ftr_fixup_test7[];
817 	extern unsigned int end_ftr_fixup_test7[];
818 	extern unsigned int ftr_fixup_test7_expected[];
819 	int size = 4 * (end_ftr_fixup_test7 - ftr_fixup_test7);
820 
821 	check(memcmp(ftr_fixup_test7, ftr_fixup_test7_expected, size) == 0);
822 }
823 
824 static void test_cpu_macros(void)
825 {
826 	extern u8 ftr_fixup_test_FTR_macros[];
827 	extern u8 ftr_fixup_test_FTR_macros_expected[];
828 	unsigned long size = ftr_fixup_test_FTR_macros_expected -
829 			     ftr_fixup_test_FTR_macros;
830 
831 	/* The fixups have already been done for us during boot */
832 	check(memcmp(ftr_fixup_test_FTR_macros,
833 		     ftr_fixup_test_FTR_macros_expected, size) == 0);
834 }
835 
836 static void test_fw_macros(void)
837 {
838 #ifdef CONFIG_PPC64
839 	extern u8 ftr_fixup_test_FW_FTR_macros[];
840 	extern u8 ftr_fixup_test_FW_FTR_macros_expected[];
841 	unsigned long size = ftr_fixup_test_FW_FTR_macros_expected -
842 			     ftr_fixup_test_FW_FTR_macros;
843 
844 	/* The fixups have already been done for us during boot */
845 	check(memcmp(ftr_fixup_test_FW_FTR_macros,
846 		     ftr_fixup_test_FW_FTR_macros_expected, size) == 0);
847 #endif
848 }
849 
850 static void test_lwsync_macros(void)
851 {
852 	extern u8 lwsync_fixup_test[];
853 	extern u8 end_lwsync_fixup_test[];
854 	extern u8 lwsync_fixup_test_expected_LWSYNC[];
855 	extern u8 lwsync_fixup_test_expected_SYNC[];
856 	unsigned long size = end_lwsync_fixup_test -
857 			     lwsync_fixup_test;
858 
859 	/* The fixups have already been done for us during boot */
860 	if (cur_cpu_spec->cpu_features & CPU_FTR_LWSYNC) {
861 		check(memcmp(lwsync_fixup_test,
862 			     lwsync_fixup_test_expected_LWSYNC, size) == 0);
863 	} else {
864 		check(memcmp(lwsync_fixup_test,
865 			     lwsync_fixup_test_expected_SYNC, size) == 0);
866 	}
867 }
868 
869 #ifdef CONFIG_PPC64
870 static void __init test_prefix_patching(void)
871 {
872 	extern unsigned int ftr_fixup_prefix1[];
873 	extern unsigned int end_ftr_fixup_prefix1[];
874 	extern unsigned int ftr_fixup_prefix1_orig[];
875 	extern unsigned int ftr_fixup_prefix1_expected[];
876 	int size = sizeof(unsigned int) * (end_ftr_fixup_prefix1 - ftr_fixup_prefix1);
877 
878 	fixup.value = fixup.mask = 8;
879 	fixup.start_off = calc_offset(&fixup, ftr_fixup_prefix1 + 1);
880 	fixup.end_off = calc_offset(&fixup, ftr_fixup_prefix1 + 3);
881 	fixup.alt_start_off = fixup.alt_end_off = 0;
882 
883 	/* Sanity check */
884 	check(memcmp(ftr_fixup_prefix1, ftr_fixup_prefix1_orig, size) == 0);
885 
886 	patch_feature_section(0, &fixup);
887 	check(memcmp(ftr_fixup_prefix1, ftr_fixup_prefix1_expected, size) == 0);
888 	check(memcmp(ftr_fixup_prefix1, ftr_fixup_prefix1_orig, size) != 0);
889 }
890 
891 static void __init test_prefix_alt_patching(void)
892 {
893 	extern unsigned int ftr_fixup_prefix2[];
894 	extern unsigned int end_ftr_fixup_prefix2[];
895 	extern unsigned int ftr_fixup_prefix2_orig[];
896 	extern unsigned int ftr_fixup_prefix2_expected[];
897 	extern unsigned int ftr_fixup_prefix2_alt[];
898 	int size = sizeof(unsigned int) * (end_ftr_fixup_prefix2 - ftr_fixup_prefix2);
899 
900 	fixup.value = fixup.mask = 8;
901 	fixup.start_off = calc_offset(&fixup, ftr_fixup_prefix2 + 1);
902 	fixup.end_off = calc_offset(&fixup, ftr_fixup_prefix2 + 3);
903 	fixup.alt_start_off = calc_offset(&fixup, ftr_fixup_prefix2_alt);
904 	fixup.alt_end_off = calc_offset(&fixup, ftr_fixup_prefix2_alt + 2);
905 	/* Sanity check */
906 	check(memcmp(ftr_fixup_prefix2, ftr_fixup_prefix2_orig, size) == 0);
907 
908 	patch_feature_section(0, &fixup);
909 	check(memcmp(ftr_fixup_prefix2, ftr_fixup_prefix2_expected, size) == 0);
910 	check(memcmp(ftr_fixup_prefix2, ftr_fixup_prefix2_orig, size) != 0);
911 }
912 
913 static void __init test_prefix_word_alt_patching(void)
914 {
915 	extern unsigned int ftr_fixup_prefix3[];
916 	extern unsigned int end_ftr_fixup_prefix3[];
917 	extern unsigned int ftr_fixup_prefix3_orig[];
918 	extern unsigned int ftr_fixup_prefix3_expected[];
919 	extern unsigned int ftr_fixup_prefix3_alt[];
920 	int size = sizeof(unsigned int) * (end_ftr_fixup_prefix3 - ftr_fixup_prefix3);
921 
922 	fixup.value = fixup.mask = 8;
923 	fixup.start_off = calc_offset(&fixup, ftr_fixup_prefix3 + 1);
924 	fixup.end_off = calc_offset(&fixup, ftr_fixup_prefix3 + 4);
925 	fixup.alt_start_off = calc_offset(&fixup, ftr_fixup_prefix3_alt);
926 	fixup.alt_end_off = calc_offset(&fixup, ftr_fixup_prefix3_alt + 3);
927 	/* Sanity check */
928 	check(memcmp(ftr_fixup_prefix3, ftr_fixup_prefix3_orig, size) == 0);
929 
930 	patch_feature_section(0, &fixup);
931 	check(memcmp(ftr_fixup_prefix3, ftr_fixup_prefix3_expected, size) == 0);
932 	patch_feature_section(0, &fixup);
933 	check(memcmp(ftr_fixup_prefix3, ftr_fixup_prefix3_orig, size) != 0);
934 }
935 #else
936 static inline void test_prefix_patching(void) {}
937 static inline void test_prefix_alt_patching(void) {}
938 static inline void test_prefix_word_alt_patching(void) {}
939 #endif /* CONFIG_PPC64 */
940 
941 static int __init test_feature_fixups(void)
942 {
943 	printk(KERN_DEBUG "Running feature fixup self-tests ...\n");
944 
945 	test_basic_patching();
946 	test_alternative_patching();
947 	test_alternative_case_too_big();
948 	test_alternative_case_too_small();
949 	test_alternative_case_with_branch();
950 	test_alternative_case_with_external_branch();
951 	test_alternative_case_with_branch_to_end();
952 	test_cpu_macros();
953 	test_fw_macros();
954 	test_lwsync_macros();
955 	test_prefix_patching();
956 	test_prefix_alt_patching();
957 	test_prefix_word_alt_patching();
958 
959 	return 0;
960 }
961 late_initcall(test_feature_fixups);
962 
963 #endif /* CONFIG_FTR_FIXUP_SELFTEST */
964