a8e4e78c91e4689e5577a4e3abbb2ee7b4b86092
[openwrt/openwrt.git] / target / linux / generic / pending-4.19 / 305-mips_module_reloc.patch
1 From: Felix Fietkau <nbd@nbd.name>
2 Subject: mips: replace -mlong-calls with -mno-long-calls to make function calls faster in kernel modules to achieve this, try to
3
4 lede-commit: 3b3d64743ba2a874df9d70cd19e242205b0a788c
5 Signed-off-by: Felix Fietkau <nbd@nbd.name>
6 ---
7 arch/mips/Makefile | 5 +
8 arch/mips/include/asm/module.h | 5 +
9 arch/mips/kernel/module.c | 279 ++++++++++++++++++++++++++++++++++++++++-
10 3 files changed, 284 insertions(+), 5 deletions(-)
11
12 --- a/arch/mips/Makefile
13 +++ b/arch/mips/Makefile
14 @@ -94,8 +94,18 @@ all-$(CONFIG_SYS_SUPPORTS_ZBOOT)+= vmlin
15 cflags-y += -G 0 -mno-abicalls -fno-pic -pipe -mno-branch-likely
16 cflags-y += -msoft-float
17 LDFLAGS_vmlinux += -G 0 -static -n -nostdlib
18 +ifdef CONFIG_64BIT
19 KBUILD_AFLAGS_MODULE += -mlong-calls
20 KBUILD_CFLAGS_MODULE += -mlong-calls
21 +else
22 + ifdef CONFIG_DYNAMIC_FTRACE
23 + KBUILD_AFLAGS_MODULE += -mlong-calls
24 + KBUILD_CFLAGS_MODULE += -mlong-calls
25 + else
26 + KBUILD_AFLAGS_MODULE += -mno-long-calls
27 + KBUILD_CFLAGS_MODULE += -mno-long-calls
28 + endif
29 +endif
30
31 ifeq ($(CONFIG_RELOCATABLE),y)
32 LDFLAGS_vmlinux += --emit-relocs
33 --- a/arch/mips/include/asm/module.h
34 +++ b/arch/mips/include/asm/module.h
35 @@ -12,6 +12,11 @@ struct mod_arch_specific {
36 const struct exception_table_entry *dbe_start;
37 const struct exception_table_entry *dbe_end;
38 struct mips_hi16 *r_mips_hi16_list;
39 +
40 + void *phys_plt_tbl;
41 + void *virt_plt_tbl;
42 + unsigned int phys_plt_offset;
43 + unsigned int virt_plt_offset;
44 };
45
46 typedef uint8_t Elf64_Byte; /* Type for a 8-bit quantity. */
47 --- a/arch/mips/kernel/module.c
48 +++ b/arch/mips/kernel/module.c
49 @@ -44,14 +44,221 @@ struct mips_hi16 {
50 static LIST_HEAD(dbe_list);
51 static DEFINE_SPINLOCK(dbe_lock);
52
53 -#ifdef MODULE_START
54 +/*
55 + * Get the potential max trampolines size required of the init and
56 + * non-init sections. Only used if we cannot find enough contiguous
57 + * physically mapped memory to put the module into.
58 + */
59 +static unsigned int
60 +get_plt_size(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
61 + const char *secstrings, unsigned int symindex, bool is_init)
62 +{
63 + unsigned long ret = 0;
64 + unsigned int i, j;
65 + Elf_Sym *syms;
66 +
67 + /* Everything marked ALLOC (this includes the exported symbols) */
68 + for (i = 1; i < hdr->e_shnum; ++i) {
69 + unsigned int info = sechdrs[i].sh_info;
70 +
71 + if (sechdrs[i].sh_type != SHT_REL
72 + && sechdrs[i].sh_type != SHT_RELA)
73 + continue;
74 +
75 + /* Not a valid relocation section? */
76 + if (info >= hdr->e_shnum)
77 + continue;
78 +
79 + /* Don't bother with non-allocated sections */
80 + if (!(sechdrs[info].sh_flags & SHF_ALLOC))
81 + continue;
82 +
83 + /* If it's called *.init*, and we're not init, we're
84 + not interested */
85 + if ((strstr(secstrings + sechdrs[i].sh_name, ".init") != 0)
86 + != is_init)
87 + continue;
88 +
89 + syms = (Elf_Sym *) sechdrs[symindex].sh_addr;
90 + if (sechdrs[i].sh_type == SHT_REL) {
91 + Elf_Mips_Rel *rel = (void *) sechdrs[i].sh_addr;
92 + unsigned int size = sechdrs[i].sh_size / sizeof(*rel);
93 +
94 + for (j = 0; j < size; ++j) {
95 + Elf_Sym *sym;
96 +
97 + if (ELF_MIPS_R_TYPE(rel[j]) != R_MIPS_26)
98 + continue;
99 +
100 + sym = syms + ELF_MIPS_R_SYM(rel[j]);
101 + if (!is_init && sym->st_shndx != SHN_UNDEF)
102 + continue;
103 +
104 + ret += 4 * sizeof(int);
105 + }
106 + } else {
107 + Elf_Mips_Rela *rela = (void *) sechdrs[i].sh_addr;
108 + unsigned int size = sechdrs[i].sh_size / sizeof(*rela);
109 +
110 + for (j = 0; j < size; ++j) {
111 + Elf_Sym *sym;
112 +
113 + if (ELF_MIPS_R_TYPE(rela[j]) != R_MIPS_26)
114 + continue;
115 +
116 + sym = syms + ELF_MIPS_R_SYM(rela[j]);
117 + if (!is_init && sym->st_shndx != SHN_UNDEF)
118 + continue;
119 +
120 + ret += 4 * sizeof(int);
121 + }
122 + }
123 + }
124 +
125 + return ret;
126 +}
127 +
128 +#ifndef MODULE_START
129 +static void *alloc_phys(unsigned long size)
130 +{
131 + unsigned order;
132 + struct page *page;
133 + struct page *p;
134 +
135 + size = PAGE_ALIGN(size);
136 + order = get_order(size);
137 +
138 + page = alloc_pages(GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN |
139 + __GFP_THISNODE, order);
140 + if (!page)
141 + return NULL;
142 +
143 + split_page(page, order);
144 +
145 + /* mark all pages except for the last one */
146 + for (p = page; p + 1 < page + (size >> PAGE_SHIFT); ++p)
147 + set_bit(PG_owner_priv_1, &p->flags);
148 +
149 + for (p = page + (size >> PAGE_SHIFT); p < page + (1 << order); ++p)
150 + __free_page(p);
151 +
152 + return page_address(page);
153 +}
154 +#endif
155 +
156 +static void free_phys(void *ptr)
157 +{
158 + struct page *page;
159 + bool free;
160 +
161 + page = virt_to_page(ptr);
162 + do {
163 + free = test_and_clear_bit(PG_owner_priv_1, &page->flags);
164 + __free_page(page);
165 + page++;
166 + } while (free);
167 +}
168 +
169 +
170 void *module_alloc(unsigned long size)
171 {
172 +#ifdef MODULE_START
173 return __vmalloc_node_range(size, 1, MODULE_START, MODULE_END,
174 GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,
175 __builtin_return_address(0));
176 +#else
177 + void *ptr;
178 +
179 + if (size == 0)
180 + return NULL;
181 +
182 + ptr = alloc_phys(size);
183 +
184 + /* If we failed to allocate physically contiguous memory,
185 + * fall back to regular vmalloc. The module loader code will
186 + * create jump tables to handle long jumps */
187 + if (!ptr)
188 + return vmalloc(size);
189 +
190 + return ptr;
191 +#endif
192 }
193 +
194 +static inline bool is_phys_addr(void *ptr)
195 +{
196 +#ifdef CONFIG_64BIT
197 + return (KSEGX((unsigned long)ptr) == CKSEG0);
198 +#else
199 + return (KSEGX(ptr) == KSEG0);
200 #endif
201 +}
202 +
203 +/* Free memory returned from module_alloc */
204 +void module_memfree(void *module_region)
205 +{
206 + if (is_phys_addr(module_region))
207 + free_phys(module_region);
208 + else
209 + vfree(module_region);
210 +}
211 +
212 +static void *__module_alloc(int size, bool phys)
213 +{
214 + void *ptr;
215 +
216 + if (phys)
217 + ptr = kmalloc(size, GFP_KERNEL);
218 + else
219 + ptr = vmalloc(size);
220 + return ptr;
221 +}
222 +
223 +static void __module_free(void *ptr)
224 +{
225 + if (is_phys_addr(ptr))
226 + kfree(ptr);
227 + else
228 + vfree(ptr);
229 +}
230 +
231 +int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
232 + char *secstrings, struct module *mod)
233 +{
234 + unsigned int symindex = 0;
235 + unsigned int core_size, init_size;
236 + int i;
237 +
238 + mod->arch.phys_plt_offset = 0;
239 + mod->arch.virt_plt_offset = 0;
240 + mod->arch.phys_plt_tbl = NULL;
241 + mod->arch.virt_plt_tbl = NULL;
242 +
243 + if (IS_ENABLED(CONFIG_64BIT))
244 + return 0;
245 +
246 + for (i = 1; i < hdr->e_shnum; i++)
247 + if (sechdrs[i].sh_type == SHT_SYMTAB)
248 + symindex = i;
249 +
250 + core_size = get_plt_size(hdr, sechdrs, secstrings, symindex, false);
251 + init_size = get_plt_size(hdr, sechdrs, secstrings, symindex, true);
252 +
253 + if ((core_size + init_size) == 0)
254 + return 0;
255 +
256 + mod->arch.phys_plt_tbl = __module_alloc(core_size + init_size, 1);
257 + if (!mod->arch.phys_plt_tbl)
258 + return -ENOMEM;
259 +
260 + mod->arch.virt_plt_tbl = __module_alloc(core_size + init_size, 0);
261 + if (!mod->arch.virt_plt_tbl) {
262 + __module_free(mod->arch.phys_plt_tbl);
263 + mod->arch.phys_plt_tbl = NULL;
264 + return -ENOMEM;
265 + }
266 +
267 + return 0;
268 +}
269
270 static int apply_r_mips_none(struct module *me, u32 *location,
271 u32 base, Elf_Addr v, bool rela)
272 @@ -67,9 +274,40 @@ static int apply_r_mips_32(struct module
273 return 0;
274 }
275
276 +static Elf_Addr add_plt_entry_to(unsigned *plt_offset,
277 + void *start, Elf_Addr v)
278 +{
279 + unsigned *tramp = start + *plt_offset;
280 + *plt_offset += 4 * sizeof(int);
281 +
282 + /* adjust carry for addiu */
283 + if (v & 0x00008000)
284 + v += 0x10000;
285 +
286 + tramp[0] = 0x3c190000 | (v >> 16); /* lui t9, hi16 */
287 + tramp[1] = 0x27390000 | (v & 0xffff); /* addiu t9, t9, lo16 */
288 + tramp[2] = 0x03200008; /* jr t9 */
289 + tramp[3] = 0x00000000; /* nop */
290 +
291 + return (Elf_Addr) tramp;
292 +}
293 +
294 +static Elf_Addr add_plt_entry(struct module *me, void *location, Elf_Addr v)
295 +{
296 + if (is_phys_addr(location))
297 + return add_plt_entry_to(&me->arch.phys_plt_offset,
298 + me->arch.phys_plt_tbl, v);
299 + else
300 + return add_plt_entry_to(&me->arch.virt_plt_offset,
301 + me->arch.virt_plt_tbl, v);
302 +
303 +}
304 +
305 static int apply_r_mips_26(struct module *me, u32 *location,
306 u32 base, Elf_Addr v, bool rela)
307 {
308 + u32 ofs = base & 0x03ffffff;
309 +
310 if (v % 4) {
311 pr_err("module %s: dangerous R_MIPS_26 relocation\n",
312 me->name);
313 @@ -77,13 +315,17 @@ static int apply_r_mips_26(struct module
314 }
315
316 if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
317 - pr_err("module %s: relocation overflow\n",
318 - me->name);
319 - return -ENOEXEC;
320 + v = add_plt_entry(me, location, v + (ofs << 2));
321 + if (!v) {
322 + pr_err("module %s: relocation overflow\n",
323 + me->name);
324 + return -ENOEXEC;
325 + }
326 + ofs = 0;
327 }
328
329 *location = (*location & ~0x03ffffff) |
330 - ((base + (v >> 2)) & 0x03ffffff);
331 + ((ofs + (v >> 2)) & 0x03ffffff);
332
333 return 0;
334 }
335 @@ -459,9 +701,36 @@ int module_finalize(const Elf_Ehdr *hdr,
336 list_add(&me->arch.dbe_list, &dbe_list);
337 spin_unlock_irq(&dbe_lock);
338 }
339 +
340 + /* Get rid of the fixup trampoline if we're running the module
341 + * from physically mapped address space */
342 + if (me->arch.phys_plt_offset == 0) {
343 + __module_free(me->arch.phys_plt_tbl);
344 + me->arch.phys_plt_tbl = NULL;
345 + }
346 + if (me->arch.virt_plt_offset == 0) {
347 + __module_free(me->arch.virt_plt_tbl);
348 + me->arch.virt_plt_tbl = NULL;
349 + }
350 +
351 return 0;
352 }
353
354 +void module_arch_freeing_init(struct module *mod)
355 +{
356 + if (mod->state == MODULE_STATE_LIVE)
357 + return;
358 +
359 + if (mod->arch.phys_plt_tbl) {
360 + __module_free(mod->arch.phys_plt_tbl);
361 + mod->arch.phys_plt_tbl = NULL;
362 + }
363 + if (mod->arch.virt_plt_tbl) {
364 + __module_free(mod->arch.virt_plt_tbl);
365 + mod->arch.virt_plt_tbl = NULL;
366 + }
367 +}
368 +
369 void module_arch_cleanup(struct module *mod)
370 {
371 spin_lock_irq(&dbe_lock);