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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/mips/kernel/module.c
Initial import
Diffstat (limited to 'arch/mips/kernel/module.c')
-rw-r--r--arch/mips/kernel/module.c298
1 files changed, 298 insertions, 0 deletions
diff --git a/arch/mips/kernel/module.c b/arch/mips/kernel/module.c
new file mode 100644
index 000000000..1833f5171
--- /dev/null
+++ b/arch/mips/kernel/module.c
@@ -0,0 +1,298 @@
+/*
+ * 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
+ *
+ * Copyright (C) 2001 Rusty Russell.
+ * Copyright (C) 2003, 2004 Ralf Baechle (ralf@linux-mips.org)
+ * Copyright (C) 2005 Thiemo Seufer
+ */
+
+#undef DEBUG
+
+#include <linux/moduleloader.h>
+#include <linux/elf.h>
+#include <linux/mm.h>
+#include <linux/numa.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/spinlock.h>
+#include <linux/jump_label.h>
+
+#include <asm/pgtable.h> /* MODULE_START */
+
+struct mips_hi16 {
+ struct mips_hi16 *next;
+ Elf_Addr *addr;
+ Elf_Addr value;
+};
+
+static LIST_HEAD(dbe_list);
+static DEFINE_SPINLOCK(dbe_lock);
+
+#ifdef MODULE_START
+void *module_alloc(unsigned long size)
+{
+ return __vmalloc_node_range(size, 1, MODULE_START, MODULE_END,
+ GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,
+ __builtin_return_address(0));
+}
+#endif
+
+int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v)
+{
+ return 0;
+}
+
+static int apply_r_mips_32_rel(struct module *me, u32 *location, Elf_Addr v)
+{
+ *location += v;
+
+ return 0;
+}
+
+static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v)
+{
+ if (v % 4) {
+ pr_err("module %s: dangerous R_MIPS_26 REL relocation\n",
+ me->name);
+ return -ENOEXEC;
+ }
+
+ if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
+ printk(KERN_ERR
+ "module %s: relocation overflow\n",
+ me->name);
+ return -ENOEXEC;
+ }
+
+ *location = (*location & ~0x03ffffff) |
+ ((*location + (v >> 2)) & 0x03ffffff);
+
+ return 0;
+}
+
+static int apply_r_mips_hi16_rel(struct module *me, u32 *location, Elf_Addr v)
+{
+ struct mips_hi16 *n;
+
+ /*
+ * We cannot relocate this one now because we don't know the value of
+ * the carry we need to add. Save the information, and let LO16 do the
+ * actual relocation.
+ */
+ n = kmalloc(sizeof *n, GFP_KERNEL);
+ if (!n)
+ return -ENOMEM;
+
+ n->addr = (Elf_Addr *)location;
+ n->value = v;
+ n->next = me->arch.r_mips_hi16_list;
+ me->arch.r_mips_hi16_list = n;
+
+ return 0;
+}
+
+static void free_relocation_chain(struct mips_hi16 *l)
+{
+ struct mips_hi16 *next;
+
+ while (l) {
+ next = l->next;
+ kfree(l);
+ l = next;
+ }
+}
+
+static int apply_r_mips_lo16_rel(struct module *me, u32 *location, Elf_Addr v)
+{
+ unsigned long insnlo = *location;
+ struct mips_hi16 *l;
+ Elf_Addr val, vallo;
+
+ /* Sign extend the addend we extract from the lo insn. */
+ vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000;
+
+ if (me->arch.r_mips_hi16_list != NULL) {
+ l = me->arch.r_mips_hi16_list;
+ while (l != NULL) {
+ struct mips_hi16 *next;
+ unsigned long insn;
+
+ /*
+ * The value for the HI16 had best be the same.
+ */
+ if (v != l->value)
+ goto out_danger;
+
+ /*
+ * Do the HI16 relocation. Note that we actually don't
+ * need to know anything about the LO16 itself, except
+ * where to find the low 16 bits of the addend needed
+ * by the LO16.
+ */
+ insn = *l->addr;
+ val = ((insn & 0xffff) << 16) + vallo;
+ val += v;
+
+ /*
+ * Account for the sign extension that will happen in
+ * the low bits.
+ */
+ val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff;
+
+ insn = (insn & ~0xffff) | val;
+ *l->addr = insn;
+
+ next = l->next;
+ kfree(l);
+ l = next;
+ }
+
+ me->arch.r_mips_hi16_list = NULL;
+ }
+
+ /*
+ * Ok, we're done with the HI16 relocs. Now deal with the LO16.
+ */
+ val = v + vallo;
+ insnlo = (insnlo & ~0xffff) | (val & 0xffff);
+ *location = insnlo;
+
+ return 0;
+
+out_danger:
+ free_relocation_chain(l);
+ me->arch.r_mips_hi16_list = NULL;
+
+ pr_err("module %s: dangerous R_MIPS_LO16 REL relocation\n", me->name);
+
+ return -ENOEXEC;
+}
+
+static int (*reloc_handlers_rel[]) (struct module *me, u32 *location,
+ Elf_Addr v) = {
+ [R_MIPS_NONE] = apply_r_mips_none,
+ [R_MIPS_32] = apply_r_mips_32_rel,
+ [R_MIPS_26] = apply_r_mips_26_rel,
+ [R_MIPS_HI16] = apply_r_mips_hi16_rel,
+ [R_MIPS_LO16] = apply_r_mips_lo16_rel
+};
+
+int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
+ unsigned int symindex, unsigned int relsec,
+ struct module *me)
+{
+ Elf_Mips_Rel *rel = (void *) sechdrs[relsec].sh_addr;
+ Elf_Sym *sym;
+ u32 *location;
+ unsigned int i;
+ Elf_Addr v;
+ int res;
+
+ pr_debug("Applying relocate section %u to %u\n", relsec,
+ sechdrs[relsec].sh_info);
+
+ me->arch.r_mips_hi16_list = NULL;
+ for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
+ /* This is where to make the change */
+ location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+ + rel[i].r_offset;
+ /* This is the symbol it is referring to */
+ sym = (Elf_Sym *)sechdrs[symindex].sh_addr
+ + ELF_MIPS_R_SYM(rel[i]);
+ if (IS_ERR_VALUE(sym->st_value)) {
+ /* Ignore unresolved weak symbol */
+ if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
+ continue;
+ printk(KERN_WARNING "%s: Unknown symbol %s\n",
+ me->name, strtab + sym->st_name);
+ return -ENOENT;
+ }
+
+ v = sym->st_value;
+
+ res = reloc_handlers_rel[ELF_MIPS_R_TYPE(rel[i])](me, location, v);
+ if (res)
+ return res;
+ }
+
+ /*
+ * Normally the hi16 list should be deallocated at this point. A
+ * malformed binary however could contain a series of R_MIPS_HI16
+ * relocations not followed by a R_MIPS_LO16 relocation. In that
+ * case, free up the list and return an error.
+ */
+ if (me->arch.r_mips_hi16_list) {
+ free_relocation_chain(me->arch.r_mips_hi16_list);
+ me->arch.r_mips_hi16_list = NULL;
+
+ return -ENOEXEC;
+ }
+
+ return 0;
+}
+
+/* Given an address, look for it in the module exception tables. */
+const struct exception_table_entry *search_module_dbetables(unsigned long addr)
+{
+ unsigned long flags;
+ const struct exception_table_entry *e = NULL;
+ struct mod_arch_specific *dbe;
+
+ spin_lock_irqsave(&dbe_lock, flags);
+ list_for_each_entry(dbe, &dbe_list, dbe_list) {
+ e = search_extable(dbe->dbe_start, dbe->dbe_end - 1, addr);
+ if (e)
+ break;
+ }
+ spin_unlock_irqrestore(&dbe_lock, flags);
+
+ /* Now, if we found one, we are running inside it now, hence
+ we cannot unload the module, hence no refcnt needed. */
+ return e;
+}
+
+/* Put in dbe list if necessary. */
+int module_finalize(const Elf_Ehdr *hdr,
+ const Elf_Shdr *sechdrs,
+ struct module *me)
+{
+ const Elf_Shdr *s;
+ char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+
+ /* Make jump label nops. */
+ jump_label_apply_nops(me);
+
+ INIT_LIST_HEAD(&me->arch.dbe_list);
+ for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
+ if (strcmp("__dbe_table", secstrings + s->sh_name) != 0)
+ continue;
+ me->arch.dbe_start = (void *)s->sh_addr;
+ me->arch.dbe_end = (void *)s->sh_addr + s->sh_size;
+ spin_lock_irq(&dbe_lock);
+ list_add(&me->arch.dbe_list, &dbe_list);
+ spin_unlock_irq(&dbe_lock);
+ }
+ return 0;
+}
+
+void module_arch_cleanup(struct module *mod)
+{
+ spin_lock_irq(&dbe_lock);
+ list_del(&mod->arch.dbe_list);
+ spin_unlock_irq(&dbe_lock);
+}