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 000000000..0c936cbf2
--- /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);
+}