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-rw-r--r--arch/s390/kernel/module.c513
1 files changed, 513 insertions, 0 deletions
diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c
new file mode 100644
index 000000000..b81bc9621
--- /dev/null
+++ b/arch/s390/kernel/module.c
@@ -0,0 +1,513 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Kernel module help for s390.
+ *
+ * S390 version
+ * Copyright IBM Corp. 2002, 2003
+ * Author(s): Arnd Bergmann (arndb@de.ibm.com)
+ * Martin Schwidefsky (schwidefsky@de.ibm.com)
+ *
+ * based on i386 version
+ * Copyright (C) 2001 Rusty Russell.
+ */
+#include <linux/module.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/moduleloader.h>
+#include <linux/bug.h>
+#include <linux/memory.h>
+#include <asm/alternative.h>
+#include <asm/nospec-branch.h>
+#include <asm/facility.h>
+
+#if 0
+#define DEBUGP printk
+#else
+#define DEBUGP(fmt , ...)
+#endif
+
+#define PLT_ENTRY_SIZE 22
+
+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, MODULES_END,
+ GFP_KERNEL, 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;
+}
+
+void module_arch_freeing_init(struct module *mod)
+{
+ if (is_livepatch_module(mod) &&
+ mod->state == MODULE_STATE_LIVE)
+ return;
+
+ vfree(mod->arch.syminfo);
+ mod->arch.syminfo = NULL;
+}
+
+static void check_rela(Elf_Rela *rela, struct module *me)
+{
+ struct mod_arch_syminfo *info;
+
+ info = me->arch.syminfo + ELF_R_SYM (rela->r_info);
+ switch (ELF_R_TYPE (rela->r_info)) {
+ case R_390_GOT12: /* 12 bit GOT offset. */
+ case R_390_GOT16: /* 16 bit GOT offset. */
+ case R_390_GOT20: /* 20 bit GOT offset. */
+ case R_390_GOT32: /* 32 bit GOT offset. */
+ case R_390_GOT64: /* 64 bit GOT offset. */
+ case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */
+ case R_390_GOTPLT12: /* 12 bit offset to jump slot. */
+ case R_390_GOTPLT16: /* 16 bit offset to jump slot. */
+ case R_390_GOTPLT20: /* 20 bit offset to jump slot. */
+ case R_390_GOTPLT32: /* 32 bit offset to jump slot. */
+ case R_390_GOTPLT64: /* 64 bit offset to jump slot. */
+ case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */
+ if (info->got_offset == -1UL) {
+ info->got_offset = me->arch.got_size;
+ me->arch.got_size += sizeof(void*);
+ }
+ break;
+ case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */
+ case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */
+ case R_390_PLT32: /* 32 bit PC relative PLT address. */
+ case R_390_PLT64: /* 64 bit PC relative PLT address. */
+ case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */
+ case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */
+ case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */
+ if (info->plt_offset == -1UL) {
+ info->plt_offset = me->arch.plt_size;
+ me->arch.plt_size += PLT_ENTRY_SIZE;
+ }
+ break;
+ case R_390_COPY:
+ case R_390_GLOB_DAT:
+ case R_390_JMP_SLOT:
+ case R_390_RELATIVE:
+ /* Only needed if we want to support loading of
+ modules linked with -shared. */
+ break;
+ }
+}
+
+/*
+ * Account for GOT and PLT relocations. We can't add sections for
+ * got and plt but we can increase the core module size.
+ */
+int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
+ char *secstrings, struct module *me)
+{
+ Elf_Shdr *symtab;
+ Elf_Sym *symbols;
+ Elf_Rela *rela;
+ char *strings;
+ int nrela, i, j;
+
+ /* Find symbol table and string table. */
+ symtab = NULL;
+ for (i = 0; i < hdr->e_shnum; i++)
+ switch (sechdrs[i].sh_type) {
+ case SHT_SYMTAB:
+ symtab = sechdrs + i;
+ break;
+ }
+ if (!symtab) {
+ printk(KERN_ERR "module %s: no symbol table\n", me->name);
+ return -ENOEXEC;
+ }
+
+ /* Allocate one syminfo structure per symbol. */
+ me->arch.nsyms = symtab->sh_size / sizeof(Elf_Sym);
+ me->arch.syminfo = vmalloc(array_size(sizeof(struct mod_arch_syminfo),
+ me->arch.nsyms));
+ if (!me->arch.syminfo)
+ return -ENOMEM;
+ symbols = (void *) hdr + symtab->sh_offset;
+ strings = (void *) hdr + sechdrs[symtab->sh_link].sh_offset;
+ for (i = 0; i < me->arch.nsyms; i++) {
+ if (symbols[i].st_shndx == SHN_UNDEF &&
+ strcmp(strings + symbols[i].st_name,
+ "_GLOBAL_OFFSET_TABLE_") == 0)
+ /* "Define" it as absolute. */
+ symbols[i].st_shndx = SHN_ABS;
+ me->arch.syminfo[i].got_offset = -1UL;
+ me->arch.syminfo[i].plt_offset = -1UL;
+ me->arch.syminfo[i].got_initialized = 0;
+ me->arch.syminfo[i].plt_initialized = 0;
+ }
+
+ /* Search for got/plt relocations. */
+ me->arch.got_size = me->arch.plt_size = 0;
+ for (i = 0; i < hdr->e_shnum; i++) {
+ if (sechdrs[i].sh_type != SHT_RELA)
+ continue;
+ nrela = sechdrs[i].sh_size / sizeof(Elf_Rela);
+ rela = (void *) hdr + sechdrs[i].sh_offset;
+ for (j = 0; j < nrela; j++)
+ check_rela(rela + j, me);
+ }
+
+ /* Increase core size by size of got & plt and set start
+ offsets for got and plt. */
+ me->core_layout.size = ALIGN(me->core_layout.size, 4);
+ me->arch.got_offset = me->core_layout.size;
+ me->core_layout.size += me->arch.got_size;
+ me->arch.plt_offset = me->core_layout.size;
+ if (me->arch.plt_size) {
+ if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_disable)
+ me->arch.plt_size += PLT_ENTRY_SIZE;
+ me->core_layout.size += me->arch.plt_size;
+ }
+ return 0;
+}
+
+static int apply_rela_bits(Elf_Addr loc, Elf_Addr val,
+ int sign, int bits, int shift,
+ void *(*write)(void *dest, const void *src, size_t len))
+{
+ unsigned long umax;
+ long min, max;
+ void *dest = (void *)loc;
+
+ if (val & ((1UL << shift) - 1))
+ return -ENOEXEC;
+ if (sign) {
+ val = (Elf_Addr)(((long) val) >> shift);
+ min = -(1L << (bits - 1));
+ max = (1L << (bits - 1)) - 1;
+ if ((long) val < min || (long) val > max)
+ return -ENOEXEC;
+ } else {
+ val >>= shift;
+ umax = ((1UL << (bits - 1)) << 1) - 1;
+ if ((unsigned long) val > umax)
+ return -ENOEXEC;
+ }
+
+ if (bits == 8) {
+ unsigned char tmp = val;
+ write(dest, &tmp, 1);
+ } else if (bits == 12) {
+ unsigned short tmp = (val & 0xfff) |
+ (*(unsigned short *) loc & 0xf000);
+ write(dest, &tmp, 2);
+ } else if (bits == 16) {
+ unsigned short tmp = val;
+ write(dest, &tmp, 2);
+ } else if (bits == 20) {
+ unsigned int tmp = (val & 0xfff) << 16 |
+ (val & 0xff000) >> 4 | (*(unsigned int *) loc & 0xf00000ff);
+ write(dest, &tmp, 4);
+ } else if (bits == 32) {
+ unsigned int tmp = val;
+ write(dest, &tmp, 4);
+ } else if (bits == 64) {
+ unsigned long tmp = val;
+ write(dest, &tmp, 8);
+ }
+ return 0;
+}
+
+static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
+ const char *strtab, struct module *me,
+ void *(*write)(void *dest, const void *src, size_t len))
+{
+ struct mod_arch_syminfo *info;
+ Elf_Addr loc, val;
+ int r_type, r_sym;
+ int rc = -ENOEXEC;
+
+ /* This is where to make the change */
+ loc = base + rela->r_offset;
+ /* This is the symbol it is referring to. Note that all
+ undefined symbols have been resolved. */
+ r_sym = ELF_R_SYM(rela->r_info);
+ r_type = ELF_R_TYPE(rela->r_info);
+ info = me->arch.syminfo + r_sym;
+ val = symtab[r_sym].st_value;
+
+ switch (r_type) {
+ case R_390_NONE: /* No relocation. */
+ rc = 0;
+ break;
+ case R_390_8: /* Direct 8 bit. */
+ case R_390_12: /* Direct 12 bit. */
+ case R_390_16: /* Direct 16 bit. */
+ case R_390_20: /* Direct 20 bit. */
+ case R_390_32: /* Direct 32 bit. */
+ case R_390_64: /* Direct 64 bit. */
+ val += rela->r_addend;
+ if (r_type == R_390_8)
+ rc = apply_rela_bits(loc, val, 0, 8, 0, write);
+ else if (r_type == R_390_12)
+ rc = apply_rela_bits(loc, val, 0, 12, 0, write);
+ else if (r_type == R_390_16)
+ rc = apply_rela_bits(loc, val, 0, 16, 0, write);
+ else if (r_type == R_390_20)
+ rc = apply_rela_bits(loc, val, 1, 20, 0, write);
+ else if (r_type == R_390_32)
+ rc = apply_rela_bits(loc, val, 0, 32, 0, write);
+ else if (r_type == R_390_64)
+ rc = apply_rela_bits(loc, val, 0, 64, 0, write);
+ break;
+ case R_390_PC16: /* PC relative 16 bit. */
+ case R_390_PC16DBL: /* PC relative 16 bit shifted by 1. */
+ case R_390_PC32DBL: /* PC relative 32 bit shifted by 1. */
+ case R_390_PC32: /* PC relative 32 bit. */
+ case R_390_PC64: /* PC relative 64 bit. */
+ val += rela->r_addend - loc;
+ if (r_type == R_390_PC16)
+ rc = apply_rela_bits(loc, val, 1, 16, 0, write);
+ else if (r_type == R_390_PC16DBL)
+ rc = apply_rela_bits(loc, val, 1, 16, 1, write);
+ else if (r_type == R_390_PC32DBL)
+ rc = apply_rela_bits(loc, val, 1, 32, 1, write);
+ else if (r_type == R_390_PC32)
+ rc = apply_rela_bits(loc, val, 1, 32, 0, write);
+ else if (r_type == R_390_PC64)
+ rc = apply_rela_bits(loc, val, 1, 64, 0, write);
+ break;
+ case R_390_GOT12: /* 12 bit GOT offset. */
+ case R_390_GOT16: /* 16 bit GOT offset. */
+ case R_390_GOT20: /* 20 bit GOT offset. */
+ case R_390_GOT32: /* 32 bit GOT offset. */
+ case R_390_GOT64: /* 64 bit GOT offset. */
+ case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */
+ case R_390_GOTPLT12: /* 12 bit offset to jump slot. */
+ case R_390_GOTPLT20: /* 20 bit offset to jump slot. */
+ case R_390_GOTPLT16: /* 16 bit offset to jump slot. */
+ case R_390_GOTPLT32: /* 32 bit offset to jump slot. */
+ case R_390_GOTPLT64: /* 64 bit offset to jump slot. */
+ case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */
+ if (info->got_initialized == 0) {
+ Elf_Addr *gotent = me->core_layout.base +
+ me->arch.got_offset +
+ info->got_offset;
+
+ write(gotent, &val, sizeof(*gotent));
+ info->got_initialized = 1;
+ }
+ val = info->got_offset + rela->r_addend;
+ if (r_type == R_390_GOT12 ||
+ r_type == R_390_GOTPLT12)
+ rc = apply_rela_bits(loc, val, 0, 12, 0, write);
+ else if (r_type == R_390_GOT16 ||
+ r_type == R_390_GOTPLT16)
+ rc = apply_rela_bits(loc, val, 0, 16, 0, write);
+ else if (r_type == R_390_GOT20 ||
+ r_type == R_390_GOTPLT20)
+ rc = apply_rela_bits(loc, val, 1, 20, 0, write);
+ else if (r_type == R_390_GOT32 ||
+ r_type == R_390_GOTPLT32)
+ rc = apply_rela_bits(loc, val, 0, 32, 0, write);
+ else if (r_type == R_390_GOT64 ||
+ r_type == R_390_GOTPLT64)
+ rc = apply_rela_bits(loc, val, 0, 64, 0, write);
+ else if (r_type == R_390_GOTENT ||
+ r_type == R_390_GOTPLTENT) {
+ val += (Elf_Addr) me->core_layout.base - loc;
+ rc = apply_rela_bits(loc, val, 1, 32, 1, write);
+ }
+ break;
+ case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */
+ case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */
+ case R_390_PLT32: /* 32 bit PC relative PLT address. */
+ case R_390_PLT64: /* 64 bit PC relative PLT address. */
+ case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */
+ case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */
+ case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */
+ if (info->plt_initialized == 0) {
+ unsigned char insn[PLT_ENTRY_SIZE];
+ char *plt_base;
+ char *ip;
+
+ plt_base = me->core_layout.base + me->arch.plt_offset;
+ ip = plt_base + info->plt_offset;
+ *(int *)insn = 0x0d10e310; /* basr 1,0 */
+ *(int *)&insn[4] = 0x100c0004; /* lg 1,12(1) */
+ if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_disable) {
+ char *jump_r1;
+
+ jump_r1 = plt_base + me->arch.plt_size -
+ PLT_ENTRY_SIZE;
+ /* brcl 0xf,__jump_r1 */
+ *(short *)&insn[8] = 0xc0f4;
+ *(int *)&insn[10] = (jump_r1 - (ip + 8)) / 2;
+ } else {
+ *(int *)&insn[8] = 0x07f10000; /* br %r1 */
+ }
+ *(long *)&insn[14] = val;
+
+ write(ip, insn, sizeof(insn));
+ info->plt_initialized = 1;
+ }
+ if (r_type == R_390_PLTOFF16 ||
+ r_type == R_390_PLTOFF32 ||
+ r_type == R_390_PLTOFF64)
+ val = me->arch.plt_offset - me->arch.got_offset +
+ info->plt_offset + rela->r_addend;
+ else {
+ if (!((r_type == R_390_PLT16DBL &&
+ val - loc + 0xffffUL < 0x1ffffeUL) ||
+ (r_type == R_390_PLT32DBL &&
+ val - loc + 0xffffffffULL < 0x1fffffffeULL)))
+ val = (Elf_Addr) me->core_layout.base +
+ me->arch.plt_offset +
+ info->plt_offset;
+ val += rela->r_addend - loc;
+ }
+ if (r_type == R_390_PLT16DBL)
+ rc = apply_rela_bits(loc, val, 1, 16, 1, write);
+ else if (r_type == R_390_PLTOFF16)
+ rc = apply_rela_bits(loc, val, 0, 16, 0, write);
+ else if (r_type == R_390_PLT32DBL)
+ rc = apply_rela_bits(loc, val, 1, 32, 1, write);
+ else if (r_type == R_390_PLT32 ||
+ r_type == R_390_PLTOFF32)
+ rc = apply_rela_bits(loc, val, 0, 32, 0, write);
+ else if (r_type == R_390_PLT64 ||
+ r_type == R_390_PLTOFF64)
+ rc = apply_rela_bits(loc, val, 0, 64, 0, write);
+ break;
+ case R_390_GOTOFF16: /* 16 bit offset to GOT. */
+ case R_390_GOTOFF32: /* 32 bit offset to GOT. */
+ case R_390_GOTOFF64: /* 64 bit offset to GOT. */
+ val = val + rela->r_addend -
+ ((Elf_Addr) me->core_layout.base + me->arch.got_offset);
+ if (r_type == R_390_GOTOFF16)
+ rc = apply_rela_bits(loc, val, 0, 16, 0, write);
+ else if (r_type == R_390_GOTOFF32)
+ rc = apply_rela_bits(loc, val, 0, 32, 0, write);
+ else if (r_type == R_390_GOTOFF64)
+ rc = apply_rela_bits(loc, val, 0, 64, 0, write);
+ break;
+ case R_390_GOTPC: /* 32 bit PC relative offset to GOT. */
+ case R_390_GOTPCDBL: /* 32 bit PC rel. off. to GOT shifted by 1. */
+ val = (Elf_Addr) me->core_layout.base + me->arch.got_offset +
+ rela->r_addend - loc;
+ if (r_type == R_390_GOTPC)
+ rc = apply_rela_bits(loc, val, 1, 32, 0, write);
+ else if (r_type == R_390_GOTPCDBL)
+ rc = apply_rela_bits(loc, val, 1, 32, 1, write);
+ break;
+ case R_390_COPY:
+ case R_390_GLOB_DAT: /* Create GOT entry. */
+ case R_390_JMP_SLOT: /* Create PLT entry. */
+ case R_390_RELATIVE: /* Adjust by program base. */
+ /* Only needed if we want to support loading of
+ modules linked with -shared. */
+ return -ENOEXEC;
+ default:
+ printk(KERN_ERR "module %s: unknown relocation: %u\n",
+ me->name, r_type);
+ return -ENOEXEC;
+ }
+ if (rc) {
+ printk(KERN_ERR "module %s: relocation error for symbol %s "
+ "(r_type %i, value 0x%lx)\n",
+ me->name, strtab + symtab[r_sym].st_name,
+ r_type, (unsigned long) val);
+ return rc;
+ }
+ return 0;
+}
+
+static int __apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
+ unsigned int symindex, unsigned int relsec,
+ struct module *me,
+ void *(*write)(void *dest, const void *src, size_t len))
+{
+ Elf_Addr base;
+ Elf_Sym *symtab;
+ Elf_Rela *rela;
+ unsigned long i, n;
+ int rc;
+
+ DEBUGP("Applying relocate section %u to %u\n",
+ relsec, sechdrs[relsec].sh_info);
+ base = sechdrs[sechdrs[relsec].sh_info].sh_addr;
+ symtab = (Elf_Sym *) sechdrs[symindex].sh_addr;
+ rela = (Elf_Rela *) sechdrs[relsec].sh_addr;
+ n = sechdrs[relsec].sh_size / sizeof(Elf_Rela);
+
+ for (i = 0; i < n; i++, rela++) {
+ rc = apply_rela(rela, base, symtab, strtab, me, write);
+ if (rc)
+ return rc;
+ }
+ return 0;
+}
+
+int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
+ unsigned int symindex, unsigned int relsec,
+ struct module *me)
+{
+ bool early = me->state == MODULE_STATE_UNFORMED;
+ void *(*write)(void *, const void *, size_t) = memcpy;
+
+ if (!early)
+ write = s390_kernel_write;
+
+ return __apply_relocate_add(sechdrs, strtab, symindex, relsec, me,
+ write);
+}
+
+int module_finalize(const Elf_Ehdr *hdr,
+ const Elf_Shdr *sechdrs,
+ struct module *me)
+{
+ const Elf_Shdr *s;
+ char *secstrings, *secname;
+ void *aseg;
+
+ if (IS_ENABLED(CONFIG_EXPOLINE) &&
+ !nospec_disable && me->arch.plt_size) {
+ unsigned int *ij;
+
+ ij = me->core_layout.base + me->arch.plt_offset +
+ me->arch.plt_size - PLT_ENTRY_SIZE;
+ if (test_facility(35)) {
+ ij[0] = 0xc6000000; /* exrl %r0,.+10 */
+ ij[1] = 0x0005a7f4; /* j . */
+ ij[2] = 0x000007f1; /* br %r1 */
+ } else {
+ ij[0] = 0x44000000 | (unsigned int)
+ offsetof(struct lowcore, br_r1_trampoline);
+ ij[1] = 0xa7f40000; /* j . */
+ }
+ }
+
+ secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+ for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
+ aseg = (void *) s->sh_addr;
+ secname = secstrings + s->sh_name;
+
+ if (!strcmp(".altinstructions", secname))
+ /* patch .altinstructions */
+ apply_alternatives(aseg, aseg + s->sh_size);
+
+ if (IS_ENABLED(CONFIG_EXPOLINE) &&
+ (str_has_prefix(secname, ".s390_indirect")))
+ nospec_revert(aseg, aseg + s->sh_size);
+
+ if (IS_ENABLED(CONFIG_EXPOLINE) &&
+ (str_has_prefix(secname, ".s390_return")))
+ nospec_revert(aseg, aseg + s->sh_size);
+ }
+
+ jump_label_apply_nops(me);
+ return 0;
+}
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