| /* |
| * AArch64 loadable module support. |
| * |
| * Copyright (C) 2012 ARM Limited |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * 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, see <http://www.gnu.org/licenses/>. |
| * |
| * Author: Will Deacon <will.deacon@arm.com> |
| */ |
| |
| #include <linux/bitops.h> |
| #include <linux/elf.h> |
| #include <linux/gfp.h> |
| #include <linux/kasan.h> |
| #include <linux/kernel.h> |
| #include <linux/mm.h> |
| #include <linux/moduleloader.h> |
| #include <linux/vmalloc.h> |
| #include <asm/alternative.h> |
| #include <asm/insn.h> |
| #include <asm/sections.h> |
| |
| void *module_alloc(unsigned long size) |
| { |
| gfp_t gfp_mask = GFP_KERNEL; |
| void *p; |
| |
| /* Silence the initial allocation */ |
| if (IS_ENABLED(CONFIG_ARM64_MODULE_PLTS)) |
| gfp_mask |= __GFP_NOWARN; |
| |
| p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base, |
| module_alloc_base + MODULES_VSIZE, |
| gfp_mask, PAGE_KERNEL_EXEC, 0, |
| NUMA_NO_NODE, __builtin_return_address(0)); |
| |
| if (!p && IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) && |
| !IS_ENABLED(CONFIG_KASAN)) |
| /* |
| * KASAN can only deal with module allocations being served |
| * from the reserved module region, since the remainder of |
| * the vmalloc region is already backed by zero shadow pages, |
| * and punching holes into it is non-trivial. Since the module |
| * region is not randomized when KASAN is enabled, it is even |
| * less likely that the module region gets exhausted, so we |
| * can simply omit this fallback in that case. |
| */ |
| p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base, |
| module_alloc_base + SZ_4G, 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; |
| } |
| |
| enum aarch64_reloc_op { |
| RELOC_OP_NONE, |
| RELOC_OP_ABS, |
| RELOC_OP_PREL, |
| RELOC_OP_PAGE, |
| }; |
| |
| static u64 do_reloc(enum aarch64_reloc_op reloc_op, __le32 *place, u64 val) |
| { |
| switch (reloc_op) { |
| case RELOC_OP_ABS: |
| return val; |
| case RELOC_OP_PREL: |
| return val - (u64)place; |
| case RELOC_OP_PAGE: |
| return (val & ~0xfff) - ((u64)place & ~0xfff); |
| case RELOC_OP_NONE: |
| return 0; |
| } |
| |
| pr_err("do_reloc: unknown relocation operation %d\n", reloc_op); |
| return 0; |
| } |
| |
| static int reloc_data(enum aarch64_reloc_op op, void *place, u64 val, int len) |
| { |
| s64 sval = do_reloc(op, place, val); |
| |
| switch (len) { |
| case 16: |
| *(s16 *)place = sval; |
| if (sval < S16_MIN || sval > U16_MAX) |
| return -ERANGE; |
| break; |
| case 32: |
| *(s32 *)place = sval; |
| if (sval < S32_MIN || sval > U32_MAX) |
| return -ERANGE; |
| break; |
| case 64: |
| *(s64 *)place = sval; |
| break; |
| default: |
| pr_err("Invalid length (%d) for data relocation\n", len); |
| return 0; |
| } |
| return 0; |
| } |
| |
| enum aarch64_insn_movw_imm_type { |
| AARCH64_INSN_IMM_MOVNZ, |
| AARCH64_INSN_IMM_MOVKZ, |
| }; |
| |
| static int reloc_insn_movw(enum aarch64_reloc_op op, __le32 *place, u64 val, |
| int lsb, enum aarch64_insn_movw_imm_type imm_type) |
| { |
| u64 imm; |
| s64 sval; |
| u32 insn = le32_to_cpu(*place); |
| |
| sval = do_reloc(op, place, val); |
| imm = sval >> lsb; |
| |
| if (imm_type == AARCH64_INSN_IMM_MOVNZ) { |
| /* |
| * For signed MOVW relocations, we have to manipulate the |
| * instruction encoding depending on whether or not the |
| * immediate is less than zero. |
| */ |
| insn &= ~(3 << 29); |
| if (sval >= 0) { |
| /* >=0: Set the instruction to MOVZ (opcode 10b). */ |
| insn |= 2 << 29; |
| } else { |
| /* |
| * <0: Set the instruction to MOVN (opcode 00b). |
| * Since we've masked the opcode already, we |
| * don't need to do anything other than |
| * inverting the new immediate field. |
| */ |
| imm = ~imm; |
| } |
| } |
| |
| /* Update the instruction with the new encoding. */ |
| insn = aarch64_insn_encode_immediate(AARCH64_INSN_IMM_16, insn, imm); |
| *place = cpu_to_le32(insn); |
| |
| if (imm > U16_MAX) |
| return -ERANGE; |
| |
| return 0; |
| } |
| |
| static int reloc_insn_imm(enum aarch64_reloc_op op, __le32 *place, u64 val, |
| int lsb, int len, enum aarch64_insn_imm_type imm_type) |
| { |
| u64 imm, imm_mask; |
| s64 sval; |
| u32 insn = le32_to_cpu(*place); |
| |
| /* Calculate the relocation value. */ |
| sval = do_reloc(op, place, val); |
| sval >>= lsb; |
| |
| /* Extract the value bits and shift them to bit 0. */ |
| imm_mask = (BIT(lsb + len) - 1) >> lsb; |
| imm = sval & imm_mask; |
| |
| /* Update the instruction's immediate field. */ |
| insn = aarch64_insn_encode_immediate(imm_type, insn, imm); |
| *place = cpu_to_le32(insn); |
| |
| /* |
| * Extract the upper value bits (including the sign bit) and |
| * shift them to bit 0. |
| */ |
| sval = (s64)(sval & ~(imm_mask >> 1)) >> (len - 1); |
| |
| /* |
| * Overflow has occurred if the upper bits are not all equal to |
| * the sign bit of the value. |
| */ |
| if ((u64)(sval + 1) >= 2) |
| return -ERANGE; |
| |
| return 0; |
| } |
| |
| static int reloc_insn_adrp(struct module *mod, __le32 *place, u64 val) |
| { |
| u32 insn; |
| |
| if (!IS_ENABLED(CONFIG_ARM64_ERRATUM_843419) || |
| !cpus_have_const_cap(ARM64_WORKAROUND_843419) || |
| ((u64)place & 0xfff) < 0xff8) |
| return reloc_insn_imm(RELOC_OP_PAGE, place, val, 12, 21, |
| AARCH64_INSN_IMM_ADR); |
| |
| /* patch ADRP to ADR if it is in range */ |
| if (!reloc_insn_imm(RELOC_OP_PREL, place, val & ~0xfff, 0, 21, |
| AARCH64_INSN_IMM_ADR)) { |
| insn = le32_to_cpu(*place); |
| insn &= ~BIT(31); |
| } else { |
| /* out of range for ADR -> emit a veneer */ |
| val = module_emit_adrp_veneer(mod, place, val & ~0xfff); |
| if (!val) |
| return -ENOEXEC; |
| insn = aarch64_insn_gen_branch_imm((u64)place, val, |
| AARCH64_INSN_BRANCH_NOLINK); |
| } |
| |
| *place = cpu_to_le32(insn); |
| return 0; |
| } |
| |
| int apply_relocate_add(Elf64_Shdr *sechdrs, |
| const char *strtab, |
| unsigned int symindex, |
| unsigned int relsec, |
| struct module *me) |
| { |
| unsigned int i; |
| int ovf; |
| bool overflow_check; |
| Elf64_Sym *sym; |
| void *loc; |
| u64 val; |
| Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr; |
| |
| for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { |
| /* loc corresponds to P in the AArch64 ELF document. */ |
| loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr |
| + rel[i].r_offset; |
| |
| /* sym is the ELF symbol we're referring to. */ |
| sym = (Elf64_Sym *)sechdrs[symindex].sh_addr |
| + ELF64_R_SYM(rel[i].r_info); |
| |
| /* val corresponds to (S + A) in the AArch64 ELF document. */ |
| val = sym->st_value + rel[i].r_addend; |
| |
| /* Check for overflow by default. */ |
| overflow_check = true; |
| |
| /* Perform the static relocation. */ |
| switch (ELF64_R_TYPE(rel[i].r_info)) { |
| /* Null relocations. */ |
| case R_ARM_NONE: |
| case R_AARCH64_NONE: |
| ovf = 0; |
| break; |
| |
| /* Data relocations. */ |
| case R_AARCH64_ABS64: |
| overflow_check = false; |
| ovf = reloc_data(RELOC_OP_ABS, loc, val, 64); |
| break; |
| case R_AARCH64_ABS32: |
| ovf = reloc_data(RELOC_OP_ABS, loc, val, 32); |
| break; |
| case R_AARCH64_ABS16: |
| ovf = reloc_data(RELOC_OP_ABS, loc, val, 16); |
| break; |
| case R_AARCH64_PREL64: |
| overflow_check = false; |
| ovf = reloc_data(RELOC_OP_PREL, loc, val, 64); |
| break; |
| case R_AARCH64_PREL32: |
| ovf = reloc_data(RELOC_OP_PREL, loc, val, 32); |
| break; |
| case R_AARCH64_PREL16: |
| ovf = reloc_data(RELOC_OP_PREL, loc, val, 16); |
| break; |
| |
| /* MOVW instruction relocations. */ |
| case R_AARCH64_MOVW_UABS_G0_NC: |
| overflow_check = false; |
| case R_AARCH64_MOVW_UABS_G0: |
| ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 0, |
| AARCH64_INSN_IMM_MOVKZ); |
| break; |
| case R_AARCH64_MOVW_UABS_G1_NC: |
| overflow_check = false; |
| case R_AARCH64_MOVW_UABS_G1: |
| ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 16, |
| AARCH64_INSN_IMM_MOVKZ); |
| break; |
| case R_AARCH64_MOVW_UABS_G2_NC: |
| overflow_check = false; |
| case R_AARCH64_MOVW_UABS_G2: |
| ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 32, |
| AARCH64_INSN_IMM_MOVKZ); |
| break; |
| case R_AARCH64_MOVW_UABS_G3: |
| /* We're using the top bits so we can't overflow. */ |
| overflow_check = false; |
| ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 48, |
| AARCH64_INSN_IMM_MOVKZ); |
| break; |
| case R_AARCH64_MOVW_SABS_G0: |
| ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 0, |
| AARCH64_INSN_IMM_MOVNZ); |
| break; |
| case R_AARCH64_MOVW_SABS_G1: |
| ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 16, |
| AARCH64_INSN_IMM_MOVNZ); |
| break; |
| case R_AARCH64_MOVW_SABS_G2: |
| ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 32, |
| AARCH64_INSN_IMM_MOVNZ); |
| break; |
| case R_AARCH64_MOVW_PREL_G0_NC: |
| overflow_check = false; |
| ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 0, |
| AARCH64_INSN_IMM_MOVKZ); |
| break; |
| case R_AARCH64_MOVW_PREL_G0: |
| ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 0, |
| AARCH64_INSN_IMM_MOVNZ); |
| break; |
| case R_AARCH64_MOVW_PREL_G1_NC: |
| overflow_check = false; |
| ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 16, |
| AARCH64_INSN_IMM_MOVKZ); |
| break; |
| case R_AARCH64_MOVW_PREL_G1: |
| ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 16, |
| AARCH64_INSN_IMM_MOVNZ); |
| break; |
| case R_AARCH64_MOVW_PREL_G2_NC: |
| overflow_check = false; |
| ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 32, |
| AARCH64_INSN_IMM_MOVKZ); |
| break; |
| case R_AARCH64_MOVW_PREL_G2: |
| ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 32, |
| AARCH64_INSN_IMM_MOVNZ); |
| break; |
| case R_AARCH64_MOVW_PREL_G3: |
| /* We're using the top bits so we can't overflow. */ |
| overflow_check = false; |
| ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 48, |
| AARCH64_INSN_IMM_MOVNZ); |
| break; |
| |
| /* Immediate instruction relocations. */ |
| case R_AARCH64_LD_PREL_LO19: |
| ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 19, |
| AARCH64_INSN_IMM_19); |
| break; |
| case R_AARCH64_ADR_PREL_LO21: |
| ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 0, 21, |
| AARCH64_INSN_IMM_ADR); |
| break; |
| case R_AARCH64_ADR_PREL_PG_HI21_NC: |
| overflow_check = false; |
| case R_AARCH64_ADR_PREL_PG_HI21: |
| ovf = reloc_insn_adrp(me, loc, val); |
| if (ovf && ovf != -ERANGE) |
| return ovf; |
| break; |
| case R_AARCH64_ADD_ABS_LO12_NC: |
| case R_AARCH64_LDST8_ABS_LO12_NC: |
| overflow_check = false; |
| ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 0, 12, |
| AARCH64_INSN_IMM_12); |
| break; |
| case R_AARCH64_LDST16_ABS_LO12_NC: |
| overflow_check = false; |
| ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 1, 11, |
| AARCH64_INSN_IMM_12); |
| break; |
| case R_AARCH64_LDST32_ABS_LO12_NC: |
| overflow_check = false; |
| ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 2, 10, |
| AARCH64_INSN_IMM_12); |
| break; |
| case R_AARCH64_LDST64_ABS_LO12_NC: |
| overflow_check = false; |
| ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 3, 9, |
| AARCH64_INSN_IMM_12); |
| break; |
| case R_AARCH64_LDST128_ABS_LO12_NC: |
| overflow_check = false; |
| ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 4, 8, |
| AARCH64_INSN_IMM_12); |
| break; |
| case R_AARCH64_TSTBR14: |
| ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 14, |
| AARCH64_INSN_IMM_14); |
| break; |
| case R_AARCH64_CONDBR19: |
| ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 19, |
| AARCH64_INSN_IMM_19); |
| break; |
| case R_AARCH64_JUMP26: |
| case R_AARCH64_CALL26: |
| ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 26, |
| AARCH64_INSN_IMM_26); |
| |
| if (IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) && |
| ovf == -ERANGE) { |
| val = module_emit_plt_entry(me, loc, &rel[i], sym); |
| if (!val) |
| return -ENOEXEC; |
| ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, |
| 26, AARCH64_INSN_IMM_26); |
| } |
| break; |
| |
| default: |
| pr_err("module %s: unsupported RELA relocation: %llu\n", |
| me->name, ELF64_R_TYPE(rel[i].r_info)); |
| return -ENOEXEC; |
| } |
| |
| if (overflow_check && ovf == -ERANGE) |
| goto overflow; |
| |
| } |
| |
| return 0; |
| |
| overflow: |
| pr_err("module %s: overflow in relocation type %d val %Lx\n", |
| me->name, (int)ELF64_R_TYPE(rel[i].r_info), val); |
| return -ENOEXEC; |
| } |
| |
| int module_finalize(const Elf_Ehdr *hdr, |
| const Elf_Shdr *sechdrs, |
| struct module *me) |
| { |
| const Elf_Shdr *s, *se; |
| const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; |
| |
| for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) { |
| if (strcmp(".altinstructions", secstrs + s->sh_name) == 0) { |
| apply_alternatives((void *)s->sh_addr, s->sh_size); |
| } |
| #ifdef CONFIG_ARM64_MODULE_PLTS |
| if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE) && |
| !strcmp(".text.ftrace_trampoline", secstrs + s->sh_name)) |
| me->arch.ftrace_trampoline = (void *)s->sh_addr; |
| #endif |
| } |
| |
| return 0; |
| } |