aboutsummaryrefslogtreecommitdiffstats
path: root/arch/powerpc/lib/feature-fixups.c
blob: 8c5a03be31e07766d123460cf8b273ed6dab6d0b (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
/*
 *  Copyright (C) 2001 Ben. Herrenschmidt (benh@kernel.crashing.org)
 *
 *  Modifications for ppc64:
 *      Copyright (C) 2003 Dave Engebretsen <engebret@us.ibm.com>
 *
 *  Copyright 2008 Michael Ellerman, IBM Corporation.
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/init.h>
#include <asm/cputable.h>
#include <asm/code-patching.h>


struct fixup_entry {
	unsigned long	mask;
	unsigned long	value;
	long		start_off;
	long		end_off;
	long		alt_start_off;
	long		alt_end_off;
};

static unsigned int *calc_addr(struct fixup_entry *fcur, long offset)
{
	/*
	 * We store the offset to the code as a negative offset from
	 * the start of the alt_entry, to support the VDSO. This
	 * routine converts that back into an actual address.
	 */
	return (unsigned int *)((unsigned long)fcur + offset);
}

static int patch_alt_instruction(unsigned int *src, unsigned int *dest,
				 unsigned int *alt_start, unsigned int *alt_end)
{
	unsigned int instr;

	instr = *src;

	if (instr_is_relative_branch(*src)) {
		unsigned int *target = (unsigned int *)branch_target(src);

		/* Branch within the section doesn't need translating */
		if (target < alt_start || target >= alt_end) {
			instr = translate_branch(dest, src);
			if (!instr)
				return 1;
		}
	}

	patch_instruction(dest, instr);

	return 0;
}

static int patch_feature_section(unsigned long value, struct fixup_entry *fcur)
{
	unsigned int *start, *end, *alt_start, *alt_end, *src, *dest;

	start = calc_addr(fcur, fcur->start_off);
	end = calc_addr(fcur, fcur->end_off);
	alt_start = calc_addr(fcur, fcur->alt_start_off);
	alt_end = calc_addr(fcur, fcur->alt_end_off);

	if ((alt_end - alt_start) > (end - start))
		return 1;

	if ((value & fcur->mask) == fcur->value)
		return 0;

	src = alt_start;
	dest = start;

	for (; src < alt_end; src++, dest++) {
		if (patch_alt_instruction(src, dest, alt_start, alt_end))
			return 1;
	}

	for (; dest < end; dest++)
		patch_instruction(dest, PPC_NOP_INSTR);

	return 0;
}

void do_feature_fixups(unsigned long value, void *fixup_start, void *fixup_end)
{
	struct fixup_entry *fcur, *fend;

	fcur = fixup_start;
	fend = fixup_end;

	for (; fcur < fend; fcur++) {
		if (patch_feature_section(value, fcur)) {
			WARN_ON(1);
			printk("Unable to patch feature section at %p - %p" \
				" with %p - %p\n",
				calc_addr(fcur, fcur->start_off),
				calc_addr(fcur, fcur->end_off),
				calc_addr(fcur, fcur->alt_start_off),
				calc_addr(fcur, fcur->alt_end_off));
		}
	}
}

void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end)
{
	unsigned int *start, *end, *dest;

	if (!(value & CPU_FTR_LWSYNC))
		return ;

	start = fixup_start;
	end = fixup_end;

	for (; start < end; start++) {
		dest = (void *)start + *start;
		patch_instruction(dest, PPC_LWSYNC_INSTR);
	}
}

#ifdef CONFIG_FTR_FIXUP_SELFTEST

#define check(x)	\
	if (!(x)) printk("feature-fixups: test failed at line %d\n", __LINE__);

/* This must be after the text it fixes up, vmlinux.lds.S enforces that atm */
static struct fixup_entry fixup;

static long calc_offset(struct fixup_entry *entry, unsigned int *p)
{
	return (unsigned long)p - (unsigned long)entry;
}

void test_basic_patching(void)
{
	extern unsigned int ftr_fixup_test1;
	extern unsigned int end_ftr_fixup_test1;
	extern unsigned int ftr_fixup_test1_orig;
	extern unsigned int ftr_fixup_test1_expected;
	int size = &end_ftr_fixup_test1 - &ftr_fixup_test1;

	fixup.value = fixup.mask = 8;
	fixup.start_off = calc_offset(&fixup, &ftr_fixup_test1 + 1);
	fixup.end_off = calc_offset(&fixup, &ftr_fixup_test1 + 2);
	fixup.alt_start_off = fixup.alt_end_off = 0;

	/* Sanity check */
	check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_orig, size) == 0);

	/* Check we don't patch if the value matches */
	patch_feature_section(8, &fixup);
	check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_orig, size) == 0);

	/* Check we do patch if the value doesn't match */
	patch_feature_section(0, &fixup);
	check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_expected, size) == 0);

	/* Check we do patch if the mask doesn't match */
	memcpy(&ftr_fixup_test1, &ftr_fixup_test1_orig, size);
	check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_orig, size) == 0);
	patch_feature_section(~8, &fixup);
	check(memcmp(&ftr_fixup_test1, &ftr_fixup_test1_expected, size) == 0);
}

static void test_alternative_patching(void)
{
	extern unsigned int ftr_fixup_test2;
	extern unsigned int end_ftr_fixup_test2;
	extern unsigned int ftr_fixup_test2_orig;
	extern unsigned int ftr_fixup_test2_alt;
	extern unsigned int ftr_fixup_test2_expected;
	int size = &end_ftr_fixup_test2 - &ftr_fixup_test2;

	fixup.value = fixup.mask = 0xF;
	fixup.start_off = calc_offset(&fixup, &ftr_fixup_test2 + 1);
	fixup.end_off = calc_offset(&fixup, &ftr_fixup_test2 + 2);
	fixup.alt_start_off = calc_offset(&fixup, &ftr_fixup_test2_alt);
	fixup.alt_end_off = calc_offset(&fixup, &ftr_fixup_test2_alt + 1);

	/* Sanity check */
	check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_orig, size) == 0);

	/* Check we don't patch if the value matches */
	patch_feature_section(0xF, &fixup);
	check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_orig, size) == 0);

	/* Check we do patch if the value doesn't match */
	patch_feature_section(0, &fixup);
	check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_expected, size) == 0);

	/* Check we do patch if the mask doesn't match */
	memcpy(&ftr_fixup_test2, &ftr_fixup_test2_orig, size);
	check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_orig, size) == 0);
	patch_feature_section(~0xF, &fixup);
	check(memcmp(&ftr_fixup_test2, &ftr_fixup_test2_expected, size) == 0);
}

static void test_alternative_case_too_big(void)
{
	extern unsigned int ftr_fixup_test3;
	extern unsigned int end_ftr_fixup_test3;
	extern unsigned int ftr_fixup_test3_orig;
	extern unsigned int ftr_fixup_test3_alt;
	int size = &end_ftr_fixup_test3 - &ftr_fixup_test3;

	fixup.value = fixup.mask = 0xC;
	fixup.start_off = calc_offset(&fixup, &ftr_fixup_test3 + 1);
	fixup.end_off = calc_offset(&fixup, &ftr_fixup_test3 + 2);
	fixup.alt_start_off = calc_offset(&fixup, &ftr_fixup_test3_alt);
	fixup.alt_end_off = calc_offset(&fixup, &ftr_fixup_test3_alt + 2);

	/* Sanity check */
	check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0);

	/* Expect nothing to be patched, and the error returned to us */
	check(patch_feature_section(0xF, &fixup) == 1);
	check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0);
	check(patch_feature_section(0, &fixup) == 1);
	check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0);
	check(patch_feature_section(~0xF, &fixup) == 1);
	check(memcmp(&ftr_fixup_test3, &ftr_fixup_test3_orig, size) == 0);
}

static void test_alternative_case_too_small(void)
{
	extern unsigned int ftr_fixup_test4;
	extern unsigned int end_ftr_fixup_test4;
	extern unsigned int ftr_fixup_test4_orig;
	extern unsigned int ftr_fixup_test4_alt;
	extern unsigned int ftr_fixup_test4_expected;
	int size = &end_ftr_fixup_test4 - &ftr_fixup_test4;
	unsigned long flag;

	/* Check a high-bit flag */
	flag = 1UL << ((sizeof(unsigned long) - 1) * 8);
	fixup.value = fixup.mask = flag;
	fixup.start_off = calc_offset(&fixup, &ftr_fixup_test4 + 1);
	fixup.end_off = calc_offset(&fixup, &ftr_fixup_test4 + 5);
	fixup.alt_start_off = calc_offset(&fixup, &ftr_fixup_test4_alt);
	fixup.alt_end_off = calc_offset(&fixup, &ftr_fixup_test4_alt + 2);

	/* Sanity check */
	check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_orig, size) == 0);

	/* Check we don't patch if the value matches */
	patch_feature_section(flag, &fixup);
	check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_orig, size) == 0);

	/* Check we do patch if the value doesn't match */
	patch_feature_section(0, &fixup);
	check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_expected, size) == 0);

	/* Check we do patch if the mask doesn't match */
	memcpy(&ftr_fixup_test4, &ftr_fixup_test4_orig, size);
	check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_orig, size) == 0);
	patch_feature_section(~flag, &fixup);
	check(memcmp(&ftr_fixup_test4, &ftr_fixup_test4_expected, size) == 0);
}

static void test_alternative_case_with_branch(void)
{
	extern unsigned int ftr_fixup_test5;
	extern unsigned int end_ftr_fixup_test5;
	extern unsigned int ftr_fixup_test5_expected;
	int size = &end_ftr_fixup_test5 - &ftr_fixup_test5;

	check(memcmp(&ftr_fixup_test5, &ftr_fixup_test5_expected, size) == 0);
}

static void test_alternative_case_with_external_branch(void)
{
	extern unsigned int ftr_fixup_test6;
	extern unsigned int end_ftr_fixup_test6;
	extern unsigned int ftr_fixup_test6_expected;
	int size = &end_ftr_fixup_test6 - &ftr_fixup_test6;

	check(memcmp(&ftr_fixup_test6, &ftr_fixup_test6_expected, size) == 0);
}

static void test_cpu_macros(void)
{
	extern void ftr_fixup_test_FTR_macros;
	extern void ftr_fixup_test_FTR_macros_expected;
	unsigned long size = &ftr_fixup_test_FTR_macros_expected -
			     &ftr_fixup_test_FTR_macros;

	/* The fixups have already been done for us during boot */
	check(memcmp(&ftr_fixup_test_FTR_macros,
		     &ftr_fixup_test_FTR_macros_expected, size) == 0);
}

static void test_fw_macros(void)
{
#ifdef CONFIG_PPC64
	extern void ftr_fixup_test_FW_FTR_macros;
	extern void ftr_fixup_test_FW_FTR_macros_expected;
	unsigned long size = &ftr_fixup_test_FW_FTR_macros_expected -
			     &ftr_fixup_test_FW_FTR_macros;

	/* The fixups have already been done for us during boot */
	check(memcmp(&ftr_fixup_test_FW_FTR_macros,
		     &ftr_fixup_test_FW_FTR_macros_expected, size) == 0);
#endif
}

static void test_lwsync_macros(void)
{
	extern void lwsync_fixup_test;
	extern void end_lwsync_fixup_test;
	extern void lwsync_fixup_test_expected_LWSYNC;
	extern void lwsync_fixup_test_expected_SYNC;
	unsigned long size = &end_lwsync_fixup_test -
			     &lwsync_fixup_test;

	/* The fixups have already been done for us during boot */
	if (cur_cpu_spec->cpu_features & CPU_FTR_LWSYNC) {
		check(memcmp(&lwsync_fixup_test,
			     &lwsync_fixup_test_expected_LWSYNC, size) == 0);
	} else {
		check(memcmp(&lwsync_fixup_test,
			     &lwsync_fixup_test_expected_SYNC, size) == 0);
	}
}

static int __init test_feature_fixups(void)
{
	printk(KERN_DEBUG "Running feature fixup self-tests ...\n");

	test_basic_patching();
	test_alternative_patching();
	test_alternative_case_too_big();
	test_alternative_case_too_small();
	test_alternative_case_with_branch();
	test_alternative_case_with_external_branch();
	test_cpu_macros();
	test_fw_macros();
	test_lwsync_macros();

	return 0;
}
late_initcall(test_feature_fixups);

#endif /* CONFIG_FTR_FIXUP_SELFTEST */