Improved modules loader, more robust and works on 64bit kernels.

Signed-off-by: Thiemo Seufer <ths@networkno.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 336 insertions, 0 deletions

diff --git a/arch/mips/kernel/module.c b/arch/mips/kernel/module.c
index 458af3c7a639..e54a7f442f8a 100644
--- a/arch/mips/kernel/module.c
+++ b/arch/mips/kernel/module.c
@@ -1,9 +1,345 @@
+/*
+ *  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/vmalloc.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/spinlock.h>
 
+struct mips_hi16 {
+        struct mips_hi16 *next;
+        Elf_Addr *addr;
+        Elf_Addr value;
+};
+
+static struct mips_hi16 *mips_hi16_list;
+
 static LIST_HEAD(dbe_list);
 static DEFINE_SPINLOCK(dbe_lock);
 
+void *module_alloc(unsigned long size)
+{
+        if (size == 0)
+                return NULL;
+        return vmalloc(size);
+}
+
+/* Free memory returned from module_alloc */
+void module_free(struct module *mod, void *module_region)
+{
+        vfree(module_region);
+        /* FIXME: If module_region == mod->init_region, trim exception
+           table entries. */
+}
+
+int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
+                              char *secstrings, struct module *mod)
+{
+        return 0;
+}
+
+static 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_32_rela(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) {
+                printk(KERN_ERR "module %s: dangerous 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_26_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+        if (v % 4) {
+                printk(KERN_ERR "module %s: dangerous 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) | ((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 = mips_hi16_list;
+        mips_hi16_list = n;
+
+        return 0;
+}
+
+static int apply_r_mips_hi16_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+        *location = (*location & 0xffff0000) |
+                    ((((long long) v + 0x8000LL) >> 16) & 0xffff);
+
+        return 0;
+}
+
+static int apply_r_mips_lo16_rel(struct module *me, u32 *location, Elf_Addr v)
+{
+        unsigned long insnlo = *location;
+        Elf_Addr val, vallo;
+
+        /* Sign extend the addend we extract from the lo insn.  */
+        vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000;
+
+        if (mips_hi16_list != NULL) {
+                struct mips_hi16 *l;
+
+                l = 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;
+                }
+
+                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:
+        printk(KERN_ERR "module %s: dangerous " "relocation\n", me->name);
+
+        return -ENOEXEC;
+}
+
+static int apply_r_mips_lo16_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+        *location = (*location & 0xffff0000) | (v & 0xffff);
+
+        return 0;
+}
+
+static int apply_r_mips_64_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+        *(Elf_Addr *)location = v;
+
+        return 0;
+}
+
+static int apply_r_mips_higher_rela(struct module *me, u32 *location,
+                                    Elf_Addr v)
+{
+        *location = (*location & 0xffff0000) |
+                    ((((long long) v + 0x80008000LL) >> 32) & 0xffff);
+
+        return 0;
+}
+
+static int apply_r_mips_highest_rela(struct module *me, u32 *location,
+                                     Elf_Addr v)
+{
+        *location = (*location & 0xffff0000) |
+                    ((((long long) v + 0x800080008000LL) >> 48) & 0xffff);
+
+        return 0;
+}
+
+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
+};
+
+static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
+                                Elf_Addr v) = {
+        [R_MIPS_NONE]           = apply_r_mips_none,
+        [R_MIPS_32]             = apply_r_mips_32_rela,
+        [R_MIPS_26]             = apply_r_mips_26_rela,
+        [R_MIPS_HI16]           = apply_r_mips_hi16_rela,
+        [R_MIPS_LO16]           = apply_r_mips_lo16_rela,
+        [R_MIPS_64]             = apply_r_mips_64_rela,
+        [R_MIPS_HIGHER]         = apply_r_mips_higher_rela,
+        [R_MIPS_HIGHEST]        = apply_r_mips_highest_rela
+};
+
+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);
+
+        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 (!sym->st_value) {
+                        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;
+        }
+
+        return 0;
+}
+
+int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
+                       unsigned int symindex, unsigned int relsec,
+                       struct module *me)
+{
+        Elf_Mips_Rela *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);
+
+        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 (!sym->st_value) {
+                        printk(KERN_WARNING "%s: Unknown symbol %s\n",
+                               me->name, strtab + sym->st_name);
+                        return -ENOENT;
+                }
+
+                v = sym->st_value + rel[i].r_addend;
+
+                res = reloc_handlers_rela[ELF_MIPS_R_TYPE(rel[i])](me, location, v);
+                if (res)
+                        return res;
+        }
+
+        return 0;
+}
+
 /* Given an address, look for it in the module exception tables. */
 const struct exception_table_entry *search_module_dbetables(unsigned long addr)
 {