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- // SPDX-License-Identifier: GPL-2.0+
- /*
- * Kernel module help for s390.
- *
- * S390 version
- * Copyright IBM Corp. 2002, 2003
- * Author(s): Arnd Bergmann ([email protected])
- * Martin Schwidefsky ([email protected])
- *
- * 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/ftrace.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>
- #include <asm/ftrace.lds.h>
- #include <asm/set_memory.h>
- #if 0
- #define DEBUGP printk
- #else
- #define DEBUGP(fmt , ...)
- #endif
- #define PLT_ENTRY_SIZE 22
- 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, MODULES_END,
- gfp_mask, PAGE_KERNEL_EXEC, 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_FUNCTION_TRACER
- void module_arch_cleanup(struct module *mod)
- {
- module_memfree(mod->arch.trampolines_start);
- }
- #endif
- 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);
- }
- #ifdef CONFIG_FUNCTION_TRACER
- static int module_alloc_ftrace_hotpatch_trampolines(struct module *me,
- const Elf_Shdr *s)
- {
- char *start, *end;
- int numpages;
- size_t size;
- size = FTRACE_HOTPATCH_TRAMPOLINES_SIZE(s->sh_size);
- numpages = DIV_ROUND_UP(size, PAGE_SIZE);
- start = module_alloc(numpages * PAGE_SIZE);
- if (!start)
- return -ENOMEM;
- set_memory_ro((unsigned long)start, numpages);
- end = start + size;
- me->arch.trampolines_start = (struct ftrace_hotpatch_trampoline *)start;
- me->arch.trampolines_end = (struct ftrace_hotpatch_trampoline *)end;
- me->arch.next_trampoline = me->arch.trampolines_start;
- return 0;
- }
- #endif /* CONFIG_FUNCTION_TRACER */
- int module_finalize(const Elf_Ehdr *hdr,
- const Elf_Shdr *sechdrs,
- struct module *me)
- {
- const Elf_Shdr *s;
- char *secstrings, *secname;
- void *aseg;
- #ifdef CONFIG_FUNCTION_TRACER
- int ret;
- #endif
- 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;
- ij[0] = 0xc6000000; /* exrl %r0,.+10 */
- ij[1] = 0x0005a7f4; /* j . */
- ij[2] = 0x000007f1; /* br %r1 */
- }
- 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);
- #ifdef CONFIG_FUNCTION_TRACER
- if (!strcmp(FTRACE_CALLSITE_SECTION, secname)) {
- ret = module_alloc_ftrace_hotpatch_trampolines(me, s);
- if (ret < 0)
- return ret;
- }
- #endif /* CONFIG_FUNCTION_TRACER */
- }
- return 0;
- }
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