Initial import

1 files changed, 256 insertions, 0 deletions

diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
new file mode 100644
index 000000000..005c03e93
--- /dev/null
+++ b/arch/x86/kernel/module.c
@@ -0,0 +1,256 @@
+/*  Kernel module help for x86.
+    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/moduleloader.h>
+#include <linux/elf.h>
+#include <linux/vmalloc.h>
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/kasan.h>
+#include <linux/bug.h>
+#include <linux/mm.h>
+#include <linux/gfp.h>
+#include <linux/jump_label.h>
+#include <linux/random.h>
+
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/setup.h>
+
+#if 0
+#define DEBUGP(fmt, ...)				\
+	printk(KERN_DEBUG fmt, ##__VA_ARGS__)
+#else
+#define DEBUGP(fmt, ...)				\
+do {							\
+	if (0)						\
+		printk(KERN_DEBUG fmt, ##__VA_ARGS__);	\
+} while (0)
+#endif
+
+#ifdef CONFIG_RANDOMIZE_BASE
+static unsigned long module_load_offset;
+
+/* Mutex protects the module_load_offset. */
+static DEFINE_MUTEX(module_kaslr_mutex);
+
+static unsigned long int get_module_load_offset(void)
+{
+	if (kaslr_enabled()) {
+		mutex_lock(&module_kaslr_mutex);
+		/*
+		 * Calculate the module_load_offset the first time this
+		 * code is called. Once calculated it stays the same until
+		 * reboot.
+		 */
+		if (module_load_offset == 0)
+			module_load_offset =
+				(get_random_int() % 1024 + 1) * PAGE_SIZE;
+		mutex_unlock(&module_kaslr_mutex);
+	}
+	return module_load_offset;
+}
+#else
+static unsigned long int get_module_load_offset(void)
+{
+	return 0;
+}
+#endif
+
+void *module_alloc(unsigned long size)
+{
+	void *p;
+
+	if (PAGE_ALIGN(size) > MODULES_LEN)
+		return NULL;
+
+	p = __vmalloc_node_range(size, MODULE_ALIGN,
+				    MODULES_VADDR + get_module_load_offset(),
+				    MODULES_END, GFP_KERNEL | __GFP_HIGHMEM,
+				    PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
+				    __builtin_return_address(0));
+	if (p && (kasan_module_alloc(p, size) < 0)) {
+		vfree(p);
+		return NULL;
+	}
+
+	return p;
+}
+
+#ifdef CONFIG_X86_32
+int apply_relocate(Elf32_Shdr *sechdrs,
+		   const char *strtab,
+		   unsigned int symindex,
+		   unsigned int relsec,
+		   struct module *me)
+{
+	unsigned int i;
+	Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
+	Elf32_Sym *sym;
+	uint32_t *location;
+
+	DEBUGP("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.  Note that all
+		   undefined symbols have been resolved.  */
+		sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
+			+ ELF32_R_SYM(rel[i].r_info);
+
+		switch (ELF32_R_TYPE(rel[i].r_info)) {
+		case R_386_32:
+			/* We add the value into the location given */
+			*location += sym->st_value;
+			break;
+		case R_386_PC32:
+			/* Add the value, subtract its position */
+			*location += sym->st_value - (uint32_t)location;
+			break;
+		default:
+			pr_err("%s: Unknown relocation: %u\n",
+			       me->name, ELF32_R_TYPE(rel[i].r_info));
+			return -ENOEXEC;
+		}
+	}
+	return 0;
+}
+#else /*X86_64*/
+int apply_relocate_add(Elf64_Shdr *sechdrs,
+		   const char *strtab,
+		   unsigned int symindex,
+		   unsigned int relsec,
+		   struct module *me)
+{
+	unsigned int i;
+	Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
+	Elf64_Sym *sym;
+	void *loc;
+	u64 val;
+
+	DEBUGP("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 */
+		loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+			+ rel[i].r_offset;
+
+		/* This is the symbol it is referring to.  Note that all
+		   undefined symbols have been resolved.  */
+		sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
+			+ ELF64_R_SYM(rel[i].r_info);
+
+		DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
+		       (int)ELF64_R_TYPE(rel[i].r_info),
+		       sym->st_value, rel[i].r_addend, (u64)loc);
+
+		val = sym->st_value + rel[i].r_addend;
+
+		switch (ELF64_R_TYPE(rel[i].r_info)) {
+		case R_X86_64_NONE:
+			break;
+		case R_X86_64_64:
+			*(u64 *)loc = val;
+			break;
+		case R_X86_64_32:
+			*(u32 *)loc = val;
+			if (val != *(u32 *)loc)
+				goto overflow;
+			break;
+		case R_X86_64_32S:
+			*(s32 *)loc = val;
+			if ((s64)val != *(s32 *)loc)
+				goto overflow;
+			break;
+		case R_X86_64_PC32:
+			val -= (u64)loc;
+			*(u32 *)loc = val;
+#if 0
+			if ((s64)val != *(s32 *)loc)
+				goto overflow;
+#endif
+			break;
+		default:
+			pr_err("%s: Unknown rela relocation: %llu\n",
+			       me->name, ELF64_R_TYPE(rel[i].r_info));
+			return -ENOEXEC;
+		}
+	}
+	return 0;
+
+overflow:
+	pr_err("overflow in relocation type %d val %Lx\n",
+	       (int)ELF64_R_TYPE(rel[i].r_info), val);
+	pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
+	       me->name);
+	return -ENOEXEC;
+}
+#endif
+
+int module_finalize(const Elf_Ehdr *hdr,
+		    const Elf_Shdr *sechdrs,
+		    struct module *me)
+{
+	const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
+		*para = NULL;
+	char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+
+	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
+		if (!strcmp(".text", secstrings + s->sh_name))
+			text = s;
+		if (!strcmp(".altinstructions", secstrings + s->sh_name))
+			alt = s;
+		if (!strcmp(".smp_locks", secstrings + s->sh_name))
+			locks = s;
+		if (!strcmp(".parainstructions", secstrings + s->sh_name))
+			para = s;
+	}
+
+	if (alt) {
+		/* patch .altinstructions */
+		void *aseg = (void *)alt->sh_addr;
+		apply_alternatives(aseg, aseg + alt->sh_size);
+	}
+	if (locks && text) {
+		void *lseg = (void *)locks->sh_addr;
+		void *tseg = (void *)text->sh_addr;
+		alternatives_smp_module_add(me, me->name,
+					    lseg, lseg + locks->sh_size,
+					    tseg, tseg + text->sh_size);
+	}
+
+	if (para) {
+		void *pseg = (void *)para->sh_addr;
+		apply_paravirt(pseg, pseg + para->sh_size);
+	}
+
+	/* make jump label nops */
+	jump_label_apply_nops(me);
+
+	return 0;
+}
+
+void module_arch_cleanup(struct module *mod)
+{
+	alternatives_smp_module_del(mod);
+}