summaryrefslogtreecommitdiff
path: root/target/linux/generic-2.6/patches-2.6.31/027-mips_module_reloc.patch
blob: f65a09c94e4bd21b46b80118c3ec03eeb83717b8 (plain)
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
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -83,7 +83,7 @@ all-$(CONFIG_BOOT_ELF64)	:= $(vmlinux-64
 cflags-y			+= -G 0 -mno-abicalls -fno-pic -pipe
 cflags-y			+= -msoft-float
 LDFLAGS_vmlinux			+= -G 0 -static -n -nostdlib
-MODFLAGS			+= -mlong-calls
+MODFLAGS			+= -mno-long-calls
 
 cflags-y += -ffreestanding
 
--- a/arch/mips/include/asm/module.h
+++ b/arch/mips/include/asm/module.h
@@ -9,6 +9,11 @@ struct mod_arch_specific {
 	struct list_head dbe_list;
 	const struct exception_table_entry *dbe_start;
 	const struct exception_table_entry *dbe_end;
+
+	void *plt_tbl;
+	unsigned int core_plt_offset;
+	unsigned int core_plt_size;
+	unsigned int init_plt_offset;
 };
 
 typedef uint8_t Elf64_Byte;		/* Type for a 8-bit quantity.  */
--- a/arch/mips/kernel/module.c
+++ b/arch/mips/kernel/module.c
@@ -43,6 +43,117 @@ static struct mips_hi16 *mips_hi16_list;
 static LIST_HEAD(dbe_list);
 static DEFINE_SPINLOCK(dbe_lock);
 
+/*
+ * Get the potential max trampolines size required of the init and
+ * non-init sections. Only used if we cannot find enough contiguous
+ * physically mapped memory to put the module into.
+ */
+static unsigned int
+get_plt_size(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
+             const char *secstrings, unsigned int symindex, bool is_init)
+{
+	unsigned long ret = 0;
+	unsigned int i, j;
+	Elf_Sym *syms;
+
+	/* Everything marked ALLOC (this includes the exported symbols) */
+	for (i = 1; i < hdr->e_shnum; ++i) {
+		unsigned int info = sechdrs[i].sh_info;
+
+		if (sechdrs[i].sh_type != SHT_REL
+		    && sechdrs[i].sh_type != SHT_RELA)
+			continue;
+
+		/* Not a valid relocation section? */
+		if (info >= hdr->e_shnum)
+			continue;
+
+		/* Don't bother with non-allocated sections */
+		if (!(sechdrs[info].sh_flags & SHF_ALLOC))
+			continue;
+
+		/* If it's called *.init*, and we're not init, we're
+                   not interested */
+		if ((strstr(secstrings + sechdrs[i].sh_name, ".init") != 0)
+		    != is_init)
+			continue;
+
+		syms = (Elf_Sym *) sechdrs[symindex].sh_addr;
+		if (sechdrs[i].sh_type == SHT_REL) {
+			Elf_Mips_Rel *rel = (void *) sechdrs[i].sh_addr;
+			unsigned int size = sechdrs[i].sh_size / sizeof(*rel);
+
+			for (j = 0; j < size; ++j) {
+				Elf_Sym *sym;
+
+				if (ELF_MIPS_R_TYPE(rel[j]) != R_MIPS_26)
+					continue;
+
+				sym = syms + ELF_MIPS_R_SYM(rel[j]);
+				if (!is_init && sym->st_shndx != SHN_UNDEF)
+					continue;
+
+				ret += 4 * sizeof(int);
+			}
+		} else {
+			Elf_Mips_Rela *rela = (void *) sechdrs[i].sh_addr;
+			unsigned int size = sechdrs[i].sh_size / sizeof(*rela);
+
+			for (j = 0; j < size; ++j) {
+				Elf_Sym *sym;
+
+				if (ELF_MIPS_R_TYPE(rela[j]) != R_MIPS_26)
+					continue;
+
+				sym = syms + ELF_MIPS_R_SYM(rela[j]);
+				if (!is_init && sym->st_shndx != SHN_UNDEF)
+					continue;
+
+				ret += 4 * sizeof(int);
+			}
+		}
+	}
+
+	return ret;
+}
+
+#ifndef MODULE_START
+static void *alloc_phys(unsigned long size)
+{
+	unsigned order;
+	struct page *page;
+	struct page *p;
+
+	size = PAGE_ALIGN(size);
+	order = get_order(size);
+
+	page = alloc_pages(GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN |
+			__GFP_THISNODE, order);
+	if (!page)
+		return NULL;
+
+	split_page(page, order);
+
+	for (p = page + (size >> PAGE_SHIFT); p < page + (1 << order); ++p)
+		__free_page(p);
+
+	return page_address(page);
+}
+#endif
+
+static void free_phys(void *ptr, unsigned long size)
+{
+	struct page *page;
+	struct page *end;
+
+	page = virt_to_page(ptr);
+	end = page + (PAGE_ALIGN(size) >> PAGE_SHIFT);
+
+	for (; page < end; ++page)
+		__free_page(page);
+}
+
+
 void *module_alloc(unsigned long size)
 {
 #ifdef MODULE_START
@@ -58,21 +169,68 @@ void *module_alloc(unsigned long size)
 
 	return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL);
 #else
+	void *ptr;
+
 	if (size == 0)
 		return NULL;
-	return vmalloc(size);
+
+	ptr = alloc_phys(size);
+
+	/* If we failed to allocate physically contiguous memory,
+	 * fall back to regular vmalloc. The module loader code will
+	 * create jump tables to handle long jumps */
+	if (!ptr)
+		return vmalloc(size);
+
+	return ptr;
+#endif
+}
+
+static inline bool is_phys_addr(void *ptr)
+{
+#ifdef CONFIG_64BIT
+	return (KSEGX((unsigned long)ptr) == CKSEG0);
+#else
+	return (KSEGX(ptr) == KSEG0);
 #endif
 }
 
 /* Free memory returned from module_alloc */
 void module_free(struct module *mod, void *module_region)
 {
-	vfree(module_region);
+	if (is_phys_addr(module_region)) {
+		if (mod->module_init == module_region)
+			free_phys(module_region, mod->init_size);
+		else if (mod->module_core == module_region)
+			free_phys(module_region, mod->core_size);
+		else
+			BUG();
+	} else {
+		vfree(module_region);
+	}
 }
 
 int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
 			      char *secstrings, struct module *mod)
 {
+	unsigned int symindex = 0;
+	unsigned int core_size, init_size;
+	int i;
+
+	for (i = 1; i < hdr->e_shnum; i++)
+		if (sechdrs[i].sh_type == SHT_SYMTAB)
+			symindex = i;
+
+	core_size = get_plt_size(hdr, sechdrs, secstrings, symindex, false);
+	init_size = get_plt_size(hdr, sechdrs, secstrings, symindex, true);
+
+	mod->arch.core_plt_offset = 0;
+	mod->arch.core_plt_size = core_size;
+	mod->arch.init_plt_offset = core_size;
+	mod->arch.plt_tbl = kmalloc(core_size + init_size, GFP_KERNEL);
+	if (!mod->arch.plt_tbl)
+		return -ENOMEM;
+
 	return 0;
 }
 
@@ -95,28 +253,40 @@ static int apply_r_mips_32_rela(struct m
 	return 0;
 }
 
-static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v)
+static Elf_Addr add_plt_entry_to(unsigned *plt_offset,
+				 void *start, Elf_Addr v)
 {
-	if (v % 4) {
-		pr_err("module %s: dangerous R_MIPS_26 REL relocation\n",
-		       me->name);
-		return -ENOEXEC;
-	}
+	unsigned *tramp = start + *plt_offset;
+	*plt_offset += 4 * sizeof(int);
 
-	if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
-		printk(KERN_ERR
-		       "module %s: relocation overflow\n",
-		       me->name);
-		return -ENOEXEC;
-	}
+	/* adjust carry for addiu */
+	if (v & 0x00008000)
+		v += 0x10000;
+
+	tramp[0] = 0x3c190000 | (v >> 16);      /* lui t9, hi16 */
+	tramp[1] = 0x27390000 | (v & 0xffff);   /* addiu t9, t9, lo16 */
+	tramp[2] = 0x03200008;                  /* jr t9 */
+	tramp[3] = 0x00000000;                  /* nop */
 
-	*location = (*location & ~0x03ffffff) |
-	            ((*location + (v >> 2)) & 0x03ffffff);
+	return (Elf_Addr) tramp;
+}
+
+static Elf_Addr add_plt_entry(struct module *me, void *location, Elf_Addr v)
+{
+	if (location >= me->module_core &&
+	    location < me->module_core + me->core_size)
+		return add_plt_entry_to(&me->arch.core_plt_offset,
+				me->arch.plt_tbl, v);
+
+	if (location >= me->module_init &&
+	    location < me->module_init + me->init_size)
+		return add_plt_entry_to(&me->arch.init_plt_offset,
+				me->arch.plt_tbl, v);
 
 	return 0;
 }
 
-static int apply_r_mips_26_rela(struct module *me, u32 *location, Elf_Addr v)
+static int set_r_mips_26(struct module *me, u32 *location, u32 ofs, Elf_Addr v)
 {
 	if (v % 4) {
 		pr_err("module %s: dangerous R_MIPS_26 RELArelocation\n",
@@ -125,17 +295,31 @@ static int apply_r_mips_26_rela(struct m
 	}
 
 	if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
-		printk(KERN_ERR
+	    v = add_plt_entry(me, location, v + (ofs << 2));
+		if (!v) {
+			printk(KERN_ERR
 		       "module %s: relocation overflow\n",
 		       me->name);
-		return -ENOEXEC;
+			return -ENOEXEC;
+		}
+		ofs = 0;
 	}
 
-	*location = (*location & ~0x03ffffff) | ((v >> 2) & 0x03ffffff);
+	*location = (*location & ~0x03ffffff) | ((ofs + (v >> 2)) & 0x03ffffff);
 
 	return 0;
 }
 
+static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v)
+{
+	return set_r_mips_26(me, location, *location & 0x03ffffff, v);
+}
+
+static int apply_r_mips_26_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+	return set_r_mips_26(me, location, 0, v);
+}
+
 static int apply_r_mips_hi16_rel(struct module *me, u32 *location, Elf_Addr v)
 {
 	struct mips_hi16 *n;
@@ -400,11 +584,23 @@ int module_finalize(const Elf_Ehdr *hdr,
 		list_add(&me->arch.dbe_list, &dbe_list);
 		spin_unlock_irq(&dbe_lock);
 	}
+
+	/* Get rid of the fixup trampoline if we're running the module
+	 * from physically mapped address space */
+	if (me->arch.core_plt_offset == 0 &&
+	    me->arch.init_plt_offset == me->arch.core_plt_size &&
+	    is_phys_addr(me->module_core)) {
+		kfree(me->arch.plt_tbl);
+		me->arch.plt_tbl = NULL;
+	}
+
 	return 0;
 }
 
 void module_arch_cleanup(struct module *mod)
 {
+	if (mod->arch.plt_tbl)
+		kfree(mod->arch.plt_tbl);
 	spin_lock_irq(&dbe_lock);
 	list_del(&mod->arch.dbe_list);
 	spin_unlock_irq(&dbe_lock);