Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / arch / powerpc / kernel / module_32.c
diff --git a/kernel/arch/powerpc/kernel/module_32.c b/kernel/arch/powerpc/kernel/module_32.c
new file mode 100644 (file)
index 0000000..c94d2e0
--- /dev/null
@@ -0,0 +1,304 @@
+/*  Kernel module help for PPC.
+    Copyright (C) 2001 Rusty Russell.
+
+    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.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/moduleloader.h>
+#include <linux/elf.h>
+#include <linux/vmalloc.h>
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/ftrace.h>
+#include <linux/cache.h>
+#include <linux/bug.h>
+#include <linux/sort.h>
+#include <asm/setup.h>
+
+/* Count how many different relocations (different symbol, different
+   addend) */
+static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num)
+{
+       unsigned int i, r_info, r_addend, _count_relocs;
+
+       _count_relocs = 0;
+       r_info = 0;
+       r_addend = 0;
+       for (i = 0; i < num; i++)
+               /* Only count 24-bit relocs, others don't need stubs */
+               if (ELF32_R_TYPE(rela[i].r_info) == R_PPC_REL24 &&
+                   (r_info != ELF32_R_SYM(rela[i].r_info) ||
+                    r_addend != rela[i].r_addend)) {
+                       _count_relocs++;
+                       r_info = ELF32_R_SYM(rela[i].r_info);
+                       r_addend = rela[i].r_addend;
+               }
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+       _count_relocs++;        /* add one for ftrace_caller */
+#endif
+       return _count_relocs;
+}
+
+static int relacmp(const void *_x, const void *_y)
+{
+       const Elf32_Rela *x, *y;
+
+       y = (Elf32_Rela *)_x;
+       x = (Elf32_Rela *)_y;
+
+       /* Compare the entire r_info (as opposed to ELF32_R_SYM(r_info) only) to
+        * make the comparison cheaper/faster. It won't affect the sorting or
+        * the counting algorithms' performance
+        */
+       if (x->r_info < y->r_info)
+               return -1;
+       else if (x->r_info > y->r_info)
+               return 1;
+       else if (x->r_addend < y->r_addend)
+               return -1;
+       else if (x->r_addend > y->r_addend)
+               return 1;
+       else
+               return 0;
+}
+
+static void relaswap(void *_x, void *_y, int size)
+{
+       uint32_t *x, *y, tmp;
+       int i;
+
+       y = (uint32_t *)_x;
+       x = (uint32_t *)_y;
+
+       for (i = 0; i < sizeof(Elf32_Rela) / sizeof(uint32_t); i++) {
+               tmp = x[i];
+               x[i] = y[i];
+               y[i] = tmp;
+       }
+}
+
+/* Get the potential trampolines size required of the init and
+   non-init sections */
+static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
+                                 const Elf32_Shdr *sechdrs,
+                                 const char *secstrings,
+                                 int is_init)
+{
+       unsigned long ret = 0;
+       unsigned i;
+
+       /* Everything marked ALLOC (this includes the exported
+           symbols) */
+       for (i = 1; i < hdr->e_shnum; i++) {
+               /* 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;
+
+               /* We don't want to look at debug sections. */
+               if (strstr(secstrings + sechdrs[i].sh_name, ".debug") != 0)
+                       continue;
+
+               if (sechdrs[i].sh_type == SHT_RELA) {
+                       pr_debug("Found relocations in section %u\n", i);
+                       pr_debug("Ptr: %p.  Number: %u\n",
+                              (void *)hdr + sechdrs[i].sh_offset,
+                              sechdrs[i].sh_size / sizeof(Elf32_Rela));
+
+                       /* Sort the relocation information based on a symbol and
+                        * addend key. This is a stable O(n*log n) complexity
+                        * alogrithm but it will reduce the complexity of
+                        * count_relocs() to linear complexity O(n)
+                        */
+                       sort((void *)hdr + sechdrs[i].sh_offset,
+                            sechdrs[i].sh_size / sizeof(Elf32_Rela),
+                            sizeof(Elf32_Rela), relacmp, relaswap);
+
+                       ret += count_relocs((void *)hdr
+                                            + sechdrs[i].sh_offset,
+                                            sechdrs[i].sh_size
+                                            / sizeof(Elf32_Rela))
+                               * sizeof(struct ppc_plt_entry);
+               }
+       }
+
+       return ret;
+}
+
+int module_frob_arch_sections(Elf32_Ehdr *hdr,
+                             Elf32_Shdr *sechdrs,
+                             char *secstrings,
+                             struct module *me)
+{
+       unsigned int i;
+
+       /* Find .plt and .init.plt sections */
+       for (i = 0; i < hdr->e_shnum; i++) {
+               if (strcmp(secstrings + sechdrs[i].sh_name, ".init.plt") == 0)
+                       me->arch.init_plt_section = i;
+               else if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0)
+                       me->arch.core_plt_section = i;
+       }
+       if (!me->arch.core_plt_section || !me->arch.init_plt_section) {
+               pr_err("Module doesn't contain .plt or .init.plt sections.\n");
+               return -ENOEXEC;
+       }
+
+       /* Override their sizes */
+       sechdrs[me->arch.core_plt_section].sh_size
+               = get_plt_size(hdr, sechdrs, secstrings, 0);
+       sechdrs[me->arch.init_plt_section].sh_size
+               = get_plt_size(hdr, sechdrs, secstrings, 1);
+       return 0;
+}
+
+static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val)
+{
+       if (entry->jump[0] == 0x3d800000 + ((val + 0x8000) >> 16)
+           && entry->jump[1] == 0x398c0000 + (val & 0xffff))
+               return 1;
+       return 0;
+}
+
+/* Set up a trampoline in the PLT to bounce us to the distant function */
+static uint32_t do_plt_call(void *location,
+                           Elf32_Addr val,
+                           Elf32_Shdr *sechdrs,
+                           struct module *mod)
+{
+       struct ppc_plt_entry *entry;
+
+       pr_debug("Doing plt for call to 0x%x at 0x%x\n", val, (unsigned int)location);
+       /* Init, or core PLT? */
+       if (location >= mod->module_core
+           && location < mod->module_core + mod->core_size)
+               entry = (void *)sechdrs[mod->arch.core_plt_section].sh_addr;
+       else
+               entry = (void *)sechdrs[mod->arch.init_plt_section].sh_addr;
+
+       /* Find this entry, or if that fails, the next avail. entry */
+       while (entry->jump[0]) {
+               if (entry_matches(entry, val)) return (uint32_t)entry;
+               entry++;
+       }
+
+       entry->jump[0] = 0x3d800000+((val+0x8000)>>16); /* lis r12,sym@ha */
+       entry->jump[1] = 0x398c0000 + (val&0xffff);     /* addi r12,r12,sym@l*/
+       entry->jump[2] = 0x7d8903a6;                    /* mtctr r12 */
+       entry->jump[3] = 0x4e800420;                    /* bctr */
+
+       pr_debug("Initialized plt for 0x%x at %p\n", val, entry);
+       return (uint32_t)entry;
+}
+
+int apply_relocate_add(Elf32_Shdr *sechdrs,
+                      const char *strtab,
+                      unsigned int symindex,
+                      unsigned int relsec,
+                      struct module *module)
+{
+       unsigned int i;
+       Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
+       Elf32_Sym *sym;
+       uint32_t *location;
+       uint32_t value;
+
+       pr_debug("Applying ADD relocate section %u to %u\n", relsec,
+              sechdrs[relsec].sh_info);
+       for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
+               /* This is where to make the change */
+               location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+                       + rela[i].r_offset;
+               /* This is the symbol it is referring to.  Note that all
+                  undefined symbols have been resolved.  */
+               sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
+                       + ELF32_R_SYM(rela[i].r_info);
+               /* `Everything is relative'. */
+               value = sym->st_value + rela[i].r_addend;
+
+               switch (ELF32_R_TYPE(rela[i].r_info)) {
+               case R_PPC_ADDR32:
+                       /* Simply set it */
+                       *(uint32_t *)location = value;
+                       break;
+
+               case R_PPC_ADDR16_LO:
+                       /* Low half of the symbol */
+                       *(uint16_t *)location = value;
+                       break;
+
+               case R_PPC_ADDR16_HI:
+                       /* Higher half of the symbol */
+                       *(uint16_t *)location = (value >> 16);
+                       break;
+
+               case R_PPC_ADDR16_HA:
+                       /* Sign-adjusted lower 16 bits: PPC ELF ABI says:
+                          (((x >> 16) + ((x & 0x8000) ? 1 : 0))) & 0xFFFF.
+                          This is the same, only sane.
+                        */
+                       *(uint16_t *)location = (value + 0x8000) >> 16;
+                       break;
+
+               case R_PPC_REL24:
+                       if ((int)(value - (uint32_t)location) < -0x02000000
+                           || (int)(value - (uint32_t)location) >= 0x02000000)
+                               value = do_plt_call(location, value,
+                                                   sechdrs, module);
+
+                       /* Only replace bits 2 through 26 */
+                       pr_debug("REL24 value = %08X. location = %08X\n",
+                              value, (uint32_t)location);
+                       pr_debug("Location before: %08X.\n",
+                              *(uint32_t *)location);
+                       *(uint32_t *)location
+                               = (*(uint32_t *)location & ~0x03fffffc)
+                               | ((value - (uint32_t)location)
+                                  & 0x03fffffc);
+                       pr_debug("Location after: %08X.\n",
+                              *(uint32_t *)location);
+                       pr_debug("ie. jump to %08X+%08X = %08X\n",
+                              *(uint32_t *)location & 0x03fffffc,
+                              (uint32_t)location,
+                              (*(uint32_t *)location & 0x03fffffc)
+                              + (uint32_t)location);
+                       break;
+
+               case R_PPC_REL32:
+                       /* 32-bit relative jump. */
+                       *(uint32_t *)location = value - (uint32_t)location;
+                       break;
+
+               default:
+                       pr_err("%s: unknown ADD relocation: %u\n",
+                              module->name,
+                              ELF32_R_TYPE(rela[i].r_info));
+                       return -ENOEXEC;
+               }
+       }
+#ifdef CONFIG_DYNAMIC_FTRACE
+       module->arch.tramp =
+               do_plt_call(module->module_core,
+                           (unsigned long)ftrace_caller,
+                           sechdrs, module);
+#endif
+       return 0;
+}