target/linux/generic/pending-4.9/305-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 @@ -93,8 +93,18 @@ 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 @@ -11,6 +11,11 @@ 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  int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v)
 271  {
 272 @@ -65,8 +272,39 @@ static int apply_r_mips_32_rel(struct mo
 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_rel(struct module *me, u32 *location, Elf_Addr v)
 306  {
 307 +       u32 ofs = *location & 0x03ffffff;
 308 +
 309         if (v % 4) {
 310                 pr_err("module %s: dangerous R_MIPS_26 REL relocation\n",
 311                        me->name);
 312 @@ -74,13 +312,17 @@ static int apply_r_mips_26_rel(struct mo
 313         }
 314
 315         if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
 316 -               pr_err("module %s: relocation overflow\n",
 317 -                      me->name);
 318 -               return -ENOEXEC;
 319 +               v = add_plt_entry(me, location, v + (ofs << 2));
 320 +               if (!v) {
 321 +                       pr_err("module %s: relocation overflow\n",
 322 +                              me->name);
 323 +                       return -ENOEXEC;
 324 +               }
 325 +               ofs = 0;
 326         }
 327
 328         *location = (*location & ~0x03ffffff) |
 329 -                   ((*location + (v >> 2)) & 0x03ffffff);
 330 +                   ((ofs + (v >> 2)) & 0x03ffffff);
 331
 332         return 0;
 333  }
 334 @@ -349,9 +591,36 @@ int module_finalize(const Elf_Ehdr *hdr,
 335                 list_add(&me->arch.dbe_list, &dbe_list);
 336                 spin_unlock_irq(&dbe_lock);
 337         }
 338 +
 339 +       /* Get rid of the fixup trampoline if we're running the module
 340 +        * from physically mapped address space */
 341 +       if (me->arch.phys_plt_offset == 0) {
 342 +               __module_free(me->arch.phys_plt_tbl);
 343 +               me->arch.phys_plt_tbl = NULL;
 344 +       }
 345 +       if (me->arch.virt_plt_offset == 0) {
 346 +               __module_free(me->arch.virt_plt_tbl);
 347 +               me->arch.virt_plt_tbl = NULL;
 348 +       }
 349 +
 350         return 0;
 351  }
 352
 353 +void module_arch_freeing_init(struct module *mod)
 354 +{
 355 +       if (mod->state == MODULE_STATE_LIVE)
 356 +               return;
 357 +
 358 +       if (mod->arch.phys_plt_tbl) {
 359 +               __module_free(mod->arch.phys_plt_tbl);
 360 +               mod->arch.phys_plt_tbl = NULL;
 361 +       }
 362 +       if (mod->arch.virt_plt_tbl) {
 363 +               __module_free(mod->arch.virt_plt_tbl);
 364 +               mod->arch.virt_plt_tbl = NULL;
 365 +       }
 366 +}
 367 +
 368  void module_arch_cleanup(struct module *mod)
 369  {
 370         spin_lock_irq(&dbe_lock);