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-rw-r--r--arch/mips/kernel/module.c453
1 files changed, 453 insertions, 0 deletions
diff --git a/arch/mips/kernel/module.c b/arch/mips/kernel/module.c
new file mode 100644
index 0000000000..0c936cbf20
--- /dev/null
+++ b/arch/mips/kernel/module.c
@@ -0,0 +1,453 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (C) 2001 Rusty Russell.
+ * Copyright (C) 2003, 2004 Ralf Baechle (ralf@linux-mips.org)
+ * Copyright (C) 2005 Thiemo Seufer
+ */
+
+#undef DEBUG
+
+#include <linux/extable.h>
+#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>
+
+extern void jump_label_apply_nops(struct module *mod);
+
+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
+
+static void apply_r_mips_32(u32 *location, u32 base, Elf_Addr v)
+{
+ *location = base + v;
+}
+
+static int apply_r_mips_26(struct module *me, u32 *location, u32 base,
+ Elf_Addr v)
+{
+ if (v % 4) {
+ pr_err("module %s: dangerous R_MIPS_26 relocation\n",
+ me->name);
+ return -ENOEXEC;
+ }
+
+ if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
+ pr_err("module %s: relocation overflow\n",
+ me->name);
+ return -ENOEXEC;
+ }
+
+ *location = (*location & ~0x03ffffff) |
+ ((base + (v >> 2)) & 0x03ffffff);
+
+ return 0;
+}
+
+static int apply_r_mips_hi16(struct module *me, u32 *location, Elf_Addr v,
+ bool rela)
+{
+ struct mips_hi16 *n;
+
+ if (rela) {
+ *location = (*location & 0xffff0000) |
+ ((((long long) v + 0x8000LL) >> 16) & 0xffff);
+ return 0;
+ }
+
+ /*
+ * 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(struct module *me, u32 *location,
+ u32 base, Elf_Addr v, bool rela)
+{
+ unsigned long insnlo = base;
+ struct mips_hi16 *l;
+ Elf_Addr val, vallo;
+
+ if (rela) {
+ *location = (*location & 0xffff0000) | (v & 0xffff);
+ return 0;
+ }
+
+ /* 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 relocation\n", me->name);
+
+ return -ENOEXEC;
+}
+
+static int apply_r_mips_pc(struct module *me, u32 *location, u32 base,
+ Elf_Addr v, unsigned int bits)
+{
+ unsigned long mask = GENMASK(bits - 1, 0);
+ unsigned long se_bits;
+ long offset;
+
+ if (v % 4) {
+ pr_err("module %s: dangerous R_MIPS_PC%u relocation\n",
+ me->name, bits);
+ return -ENOEXEC;
+ }
+
+ /* retrieve & sign extend implicit addend if any */
+ offset = base & mask;
+ offset |= (offset & BIT(bits - 1)) ? ~mask : 0;
+
+ offset += ((long)v - (long)location) >> 2;
+
+ /* check the sign bit onwards are identical - ie. we didn't overflow */
+ se_bits = (offset & BIT(bits - 1)) ? ~0ul : 0;
+ if ((offset & ~mask) != (se_bits & ~mask)) {
+ pr_err("module %s: relocation overflow\n", me->name);
+ return -ENOEXEC;
+ }
+
+ *location = (*location & ~mask) | (offset & mask);
+
+ return 0;
+}
+
+static int apply_r_mips_pc16(struct module *me, u32 *location, u32 base,
+ Elf_Addr v)
+{
+ return apply_r_mips_pc(me, location, base, v, 16);
+}
+
+static int apply_r_mips_pc21(struct module *me, u32 *location, u32 base,
+ Elf_Addr v)
+{
+ return apply_r_mips_pc(me, location, base, v, 21);
+}
+
+static int apply_r_mips_pc26(struct module *me, u32 *location, u32 base,
+ Elf_Addr v)
+{
+ return apply_r_mips_pc(me, location, base, v, 26);
+}
+
+static int apply_r_mips_64(u32 *location, Elf_Addr v, bool rela)
+{
+ if (WARN_ON(!rela))
+ return -EINVAL;
+
+ *(Elf_Addr *)location = v;
+
+ return 0;
+}
+
+static int apply_r_mips_higher(u32 *location, Elf_Addr v, bool rela)
+{
+ if (WARN_ON(!rela))
+ return -EINVAL;
+
+ *location = (*location & 0xffff0000) |
+ ((((long long)v + 0x80008000LL) >> 32) & 0xffff);
+
+ return 0;
+}
+
+static int apply_r_mips_highest(u32 *location, Elf_Addr v, bool rela)
+{
+ if (WARN_ON(!rela))
+ return -EINVAL;
+
+ *location = (*location & 0xffff0000) |
+ ((((long long)v + 0x800080008000LL) >> 48) & 0xffff);
+
+ return 0;
+}
+
+/**
+ * reloc_handler() - Apply a particular relocation to a module
+ * @type: type of the relocation to apply
+ * @me: the module to apply the reloc to
+ * @location: the address at which the reloc is to be applied
+ * @base: the existing value at location for REL-style; 0 for RELA-style
+ * @v: the value of the reloc, with addend for RELA-style
+ * @rela: indication of is this a RELA (true) or REL (false) relocation
+ *
+ * Each implemented relocation function applies a particular type of
+ * relocation to the module @me. Relocs that may be found in either REL or RELA
+ * variants can be handled by making use of the @base & @v parameters which are
+ * set to values which abstract the difference away from the particular reloc
+ * implementations.
+ *
+ * Return: 0 upon success, else -ERRNO
+ */
+static int reloc_handler(u32 type, struct module *me, u32 *location, u32 base,
+ Elf_Addr v, bool rela)
+{
+ switch (type) {
+ case R_MIPS_NONE:
+ break;
+ case R_MIPS_32:
+ apply_r_mips_32(location, base, v);
+ break;
+ case R_MIPS_26:
+ return apply_r_mips_26(me, location, base, v);
+ case R_MIPS_HI16:
+ return apply_r_mips_hi16(me, location, v, rela);
+ case R_MIPS_LO16:
+ return apply_r_mips_lo16(me, location, base, v, rela);
+ case R_MIPS_PC16:
+ return apply_r_mips_pc16(me, location, base, v);
+ case R_MIPS_PC21_S2:
+ return apply_r_mips_pc21(me, location, base, v);
+ case R_MIPS_PC26_S2:
+ return apply_r_mips_pc26(me, location, base, v);
+ case R_MIPS_64:
+ return apply_r_mips_64(location, v, rela);
+ case R_MIPS_HIGHER:
+ return apply_r_mips_higher(location, v, rela);
+ case R_MIPS_HIGHEST:
+ return apply_r_mips_highest(location, v, rela);
+ default:
+ pr_err("%s: Unknown relocation type %u\n", me->name, type);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int __apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
+ unsigned int symindex, unsigned int relsec,
+ struct module *me, bool rela)
+{
+ union {
+ Elf_Mips_Rel *rel;
+ Elf_Mips_Rela *rela;
+ } r;
+ Elf_Sym *sym;
+ u32 *location, base;
+ unsigned int i, type;
+ Elf_Addr v;
+ int err = 0;
+ size_t reloc_sz;
+
+ pr_debug("Applying relocate section %u to %u\n", relsec,
+ sechdrs[relsec].sh_info);
+
+ r.rel = (void *)sechdrs[relsec].sh_addr;
+ reloc_sz = rela ? sizeof(*r.rela) : sizeof(*r.rel);
+ me->arch.r_mips_hi16_list = NULL;
+ for (i = 0; i < sechdrs[relsec].sh_size / reloc_sz; i++) {
+ /* This is where to make the change */
+ location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+ + r.rel->r_offset;
+ /* This is the symbol it is referring to */
+ sym = (Elf_Sym *)sechdrs[symindex].sh_addr
+ + ELF_MIPS_R_SYM(*r.rel);
+ if (sym->st_value >= -MAX_ERRNO) {
+ /* Ignore unresolved weak symbol */
+ if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
+ continue;
+ pr_warn("%s: Unknown symbol %s\n",
+ me->name, strtab + sym->st_name);
+ err = -ENOENT;
+ goto out;
+ }
+
+ type = ELF_MIPS_R_TYPE(*r.rel);
+
+ if (rela) {
+ v = sym->st_value + r.rela->r_addend;
+ base = 0;
+ r.rela = &r.rela[1];
+ } else {
+ v = sym->st_value;
+ base = *location;
+ r.rel = &r.rel[1];
+ }
+
+ err = reloc_handler(type, me, location, base, v, rela);
+ if (err)
+ goto out;
+ }
+
+out:
+ /*
+ * 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, or if we hit
+ * an error processing a reloc we might have gotten here before
+ * reaching the R_MIPS_LO16. In either 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;
+ err = err ?: -ENOEXEC;
+ }
+
+ return err;
+}
+
+int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
+ unsigned int symindex, unsigned int relsec,
+ struct module *me)
+{
+ return __apply_relocate(sechdrs, strtab, symindex, relsec, me, false);
+}
+
+#ifdef CONFIG_MODULES_USE_ELF_RELA
+int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
+ unsigned int symindex, unsigned int relsec,
+ struct module *me)
+{
+ return __apply_relocate(sechdrs, strtab, symindex, relsec, me, true);
+}
+#endif /* CONFIG_MODULES_USE_ELF_RELA */
+
+/* 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 - dbe->dbe_start, 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;
+
+ if (IS_ENABLED(CONFIG_JUMP_LABEL))
+ 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);
+}
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