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-rw-r--r--arch/x86/kernel/module.c323
1 files changed, 323 insertions, 0 deletions
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
new file mode 100644
index 000000000..c032edcd3
--- /dev/null
+++ b/arch/x86/kernel/module.c
@@ -0,0 +1,323 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Kernel module help for x86.
+ Copyright (C) 2001 Rusty Russell.
+
+*/
+
+#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 <linux/memory.h>
+
+#include <asm/text-patching.h>
+#include <asm/page.h>
+#include <asm/setup.h>
+#include <asm/unwind.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 =
+ (prandom_u32_max(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)
+{
+ gfp_t gfp_mask = GFP_KERNEL;
+ 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_mask,
+ PAGE_KERNEL, VM_DEFER_KMEMLEAK, NUMA_NO_NODE,
+ __builtin_return_address(0));
+ if (p && (kasan_alloc_module_shadow(p, size, gfp_mask) < 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:
+ case R_386_PLT32:
+ /* 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*/
+static int __apply_relocate_add(Elf64_Shdr *sechdrs,
+ const char *strtab,
+ unsigned int symindex,
+ unsigned int relsec,
+ struct module *me,
+ void *(*write)(void *dest, const void *src, size_t len))
+{
+ 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:
+ if (*(u64 *)loc != 0)
+ goto invalid_relocation;
+ write(loc, &val, 8);
+ break;
+ case R_X86_64_32:
+ if (*(u32 *)loc != 0)
+ goto invalid_relocation;
+ write(loc, &val, 4);
+ if (val != *(u32 *)loc)
+ goto overflow;
+ break;
+ case R_X86_64_32S:
+ if (*(s32 *)loc != 0)
+ goto invalid_relocation;
+ write(loc, &val, 4);
+ if ((s64)val != *(s32 *)loc)
+ goto overflow;
+ break;
+ case R_X86_64_PC32:
+ case R_X86_64_PLT32:
+ if (*(u32 *)loc != 0)
+ goto invalid_relocation;
+ val -= (u64)loc;
+ write(loc, &val, 4);
+#if 0
+ if ((s64)val != *(s32 *)loc)
+ goto overflow;
+#endif
+ break;
+ case R_X86_64_PC64:
+ if (*(u64 *)loc != 0)
+ goto invalid_relocation;
+ val -= (u64)loc;
+ write(loc, &val, 8);
+ break;
+ default:
+ pr_err("%s: Unknown rela relocation: %llu\n",
+ me->name, ELF64_R_TYPE(rel[i].r_info));
+ return -ENOEXEC;
+ }
+ }
+ return 0;
+
+invalid_relocation:
+ pr_err("x86/modules: Skipping invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
+ (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
+ return -ENOEXEC;
+
+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;
+}
+
+int apply_relocate_add(Elf64_Shdr *sechdrs,
+ const char *strtab,
+ unsigned int symindex,
+ unsigned int relsec,
+ struct module *me)
+{
+ int ret;
+ bool early = me->state == MODULE_STATE_UNFORMED;
+ void *(*write)(void *, const void *, size_t) = memcpy;
+
+ if (!early) {
+ write = text_poke;
+ mutex_lock(&text_mutex);
+ }
+
+ ret = __apply_relocate_add(sechdrs, strtab, symindex, relsec, me,
+ write);
+
+ if (!early) {
+ text_poke_sync();
+ mutex_unlock(&text_mutex);
+ }
+
+ return ret;
+}
+
+#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, *orc = NULL, *orc_ip = NULL,
+ *retpolines = NULL, *returns = NULL, *ibt_endbr = 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 (!strcmp(".orc_unwind", secstrings + s->sh_name))
+ orc = s;
+ if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
+ orc_ip = s;
+ if (!strcmp(".retpoline_sites", secstrings + s->sh_name))
+ retpolines = s;
+ if (!strcmp(".return_sites", secstrings + s->sh_name))
+ returns = s;
+ if (!strcmp(".ibt_endbr_seal", secstrings + s->sh_name))
+ ibt_endbr = s;
+ }
+
+ /*
+ * See alternative_instructions() for the ordering rules between the
+ * various patching types.
+ */
+ if (para) {
+ void *pseg = (void *)para->sh_addr;
+ apply_paravirt(pseg, pseg + para->sh_size);
+ }
+ if (retpolines) {
+ void *rseg = (void *)retpolines->sh_addr;
+ apply_retpolines(rseg, rseg + retpolines->sh_size);
+ }
+ if (returns) {
+ void *rseg = (void *)returns->sh_addr;
+ apply_returns(rseg, rseg + returns->sh_size);
+ }
+ if (alt) {
+ /* patch .altinstructions */
+ void *aseg = (void *)alt->sh_addr;
+ apply_alternatives(aseg, aseg + alt->sh_size);
+ }
+ if (ibt_endbr) {
+ void *iseg = (void *)ibt_endbr->sh_addr;
+ apply_ibt_endbr(iseg, iseg + ibt_endbr->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 (orc && orc_ip)
+ unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
+ (void *)orc->sh_addr, orc->sh_size);
+
+ return 0;
+}
+
+void module_arch_cleanup(struct module *mod)
+{
+ alternatives_smp_module_del(mod);
+}
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