diff options
Diffstat (limited to 'arch/s390/kernel/module.c')
| -rw-r--r-- | arch/s390/kernel/module.c | 576 |
1 files changed, 576 insertions, 0 deletions
diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c new file mode 100644 index 0000000000..42215f9404 --- /dev/null +++ b/arch/s390/kernel/module.c @@ -0,0 +1,576 @@ +// 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/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> +#include <asm/setup.h> + +#if 0 +#define DEBUGP printk +#else +#define DEBUGP(fmt , ...) +#endif + +#define PLT_ENTRY_SIZE 22 + +static unsigned long get_module_load_offset(void) +{ + static DEFINE_MUTEX(module_kaslr_mutex); + static unsigned long module_load_offset; + + if (!kaslr_enabled()) + return 0; + /* + * Calculate the module_load_offset the first time this code + * is called. Once calculated it stays the same until reboot. + */ + mutex_lock(&module_kaslr_mutex); + if (!module_load_offset) + module_load_offset = get_random_u32_inclusive(1, 1024) * PAGE_SIZE; + mutex_unlock(&module_kaslr_mutex); + return module_load_offset; +} + +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_FLUSH_RESET_PERMS | 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; + struct module_memory *mod_mem; + + /* 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. */ + mod_mem = &me->mem[MOD_TEXT]; + mod_mem->size = ALIGN(mod_mem->size, 4); + me->arch.got_offset = mod_mem->size; + mod_mem->size += me->arch.got_size; + me->arch.plt_offset = mod_mem->size; + if (me->arch.plt_size) { + if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_disable) + me->arch.plt_size += PLT_ENTRY_SIZE; + mod_mem->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->mem[MOD_TEXT].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->mem[MOD_TEXT].base + + me->arch.got_offset - 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->mem[MOD_TEXT].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->mem[MOD_TEXT].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->mem[MOD_TEXT].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->mem[MOD_TEXT].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_rox((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->mem[MOD_TEXT].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; +} |