diff options
Diffstat (limited to 'arch/arm64/kernel/module.c')
| -rw-r--r-- | arch/arm64/kernel/module.c | 403 |
1 files changed, 233 insertions, 170 deletions
diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c index ca0e3d55da99..24adb581af0e 100644 --- a/arch/arm64/kernel/module.c +++ b/arch/arm64/kernel/module.c @@ -1,37 +1,29 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * 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> */ +#define pr_fmt(fmt) "Modules: " fmt + #include <linux/bitops.h> #include <linux/elf.h> -#include <linux/gfp.h> +#include <linux/ftrace.h> +#include <linux/kasan.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/moduleloader.h> -#include <linux/vmalloc.h> +#include <linux/random.h> +#include <linux/scs.h> -void *module_alloc(unsigned long size) -{ - return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END, - GFP_KERNEL, PAGE_KERNEL_EXEC, -1, - __builtin_return_address(0)); -} +#include <asm/alternative.h> +#include <asm/insn.h> +#include <asm/scs.h> +#include <asm/sections.h> +#include <asm/text-patching.h> enum aarch64_reloc_op { RELOC_OP_NONE, @@ -40,7 +32,7 @@ enum aarch64_reloc_op { RELOC_OP_PAGE, }; -static u64 do_reloc(enum aarch64_reloc_op reloc_op, void *place, u64 val) +static u64 do_reloc(enum aarch64_reloc_op reloc_op, __le32 *place, u64 val) { switch (reloc_op) { case RELOC_OP_ABS: @@ -57,69 +49,99 @@ static u64 do_reloc(enum aarch64_reloc_op reloc_op, void *place, u64 val) return 0; } -static int reloc_data(enum aarch64_reloc_op op, void *place, u64 val, int len) +#define WRITE_PLACE(place, val, mod) do { \ + __typeof__(val) __val = (val); \ + \ + if (mod->state == MODULE_STATE_UNFORMED) \ + *(place) = __val; \ + else \ + aarch64_insn_copy(place, &(__val), sizeof(*place)); \ +} while (0) + +static int reloc_data(enum aarch64_reloc_op op, void *place, u64 val, int len, + struct module *me) { - u64 imm_mask = (1 << len) - 1; s64 sval = do_reloc(op, place, val); + /* + * The ELF psABI for AArch64 documents the 16-bit and 32-bit place + * relative and absolute relocations as having a range of [-2^15, 2^16) + * or [-2^31, 2^32), respectively. However, in order to be able to + * detect overflows reliably, we have to choose whether we interpret + * such quantities as signed or as unsigned, and stick with it. + * The way we organize our address space requires a signed + * interpretation of 32-bit relative references, so let's use that + * for all R_AARCH64_PRELxx relocations. This means our upper + * bound for overflow detection should be Sxx_MAX rather than Uxx_MAX. + */ + switch (len) { case 16: - *(s16 *)place = sval; + WRITE_PLACE((s16 *)place, sval, me); + switch (op) { + case RELOC_OP_ABS: + if (sval < 0 || sval > U16_MAX) + return -ERANGE; + break; + case RELOC_OP_PREL: + if (sval < S16_MIN || sval > S16_MAX) + return -ERANGE; + break; + default: + pr_err("Invalid 16-bit data relocation (%d)\n", op); + return 0; + } break; case 32: - *(s32 *)place = sval; + WRITE_PLACE((s32 *)place, sval, me); + switch (op) { + case RELOC_OP_ABS: + if (sval < 0 || sval > U32_MAX) + return -ERANGE; + break; + case RELOC_OP_PREL: + if (sval < S32_MIN || sval > S32_MAX) + return -ERANGE; + break; + default: + pr_err("Invalid 32-bit data relocation (%d)\n", op); + return 0; + } break; case 64: - *(s64 *)place = sval; + WRITE_PLACE((s64 *)place, sval, me); break; default: pr_err("Invalid length (%d) for data relocation\n", len); return 0; } - - /* - * 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 value is not representable in - * len bits (i.e the bottom len bits are not sign-extended and - * the top bits are not all zero). - */ - if ((u64)(sval + 1) > 2) - return -ERANGE; - return 0; } -enum aarch64_imm_type { - INSN_IMM_MOVNZ, - INSN_IMM_MOVK, - INSN_IMM_ADR, - INSN_IMM_26, - INSN_IMM_19, - INSN_IMM_16, - INSN_IMM_14, - INSN_IMM_12, - INSN_IMM_9, +enum aarch64_insn_movw_imm_type { + AARCH64_INSN_IMM_MOVNZ, + AARCH64_INSN_IMM_MOVKZ, }; -static u32 encode_insn_immediate(enum aarch64_imm_type type, u32 insn, u64 imm) +static int reloc_insn_movw(enum aarch64_reloc_op op, __le32 *place, u64 val, + int lsb, enum aarch64_insn_movw_imm_type imm_type, + struct module *me) { - u32 immlo, immhi, lomask, himask, mask; - int shift; + u64 imm; + s64 sval; + u32 insn = le32_to_cpu(*place); - switch (type) { - case INSN_IMM_MOVNZ: + 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 ((s64)imm >= 0) { + if (sval >= 0) { /* >=0: Set the instruction to MOVZ (opcode 10b). */ insn |= 2 << 29; } else { @@ -131,98 +153,25 @@ static u32 encode_insn_immediate(enum aarch64_imm_type type, u32 insn, u64 imm) */ imm = ~imm; } - case INSN_IMM_MOVK: - mask = BIT(16) - 1; - shift = 5; - break; - case INSN_IMM_ADR: - lomask = 0x3; - himask = 0x7ffff; - immlo = imm & lomask; - imm >>= 2; - immhi = imm & himask; - imm = (immlo << 24) | (immhi); - mask = (lomask << 24) | (himask); - shift = 5; - break; - case INSN_IMM_26: - mask = BIT(26) - 1; - shift = 0; - break; - case INSN_IMM_19: - mask = BIT(19) - 1; - shift = 5; - break; - case INSN_IMM_16: - mask = BIT(16) - 1; - shift = 5; - break; - case INSN_IMM_14: - mask = BIT(14) - 1; - shift = 5; - break; - case INSN_IMM_12: - mask = BIT(12) - 1; - shift = 10; - break; - case INSN_IMM_9: - mask = BIT(9) - 1; - shift = 12; - break; - default: - pr_err("encode_insn_immediate: unknown immediate encoding %d\n", - type); - return 0; } - /* Update the immediate field. */ - insn &= ~(mask << shift); - insn |= (imm & mask) << shift; - - return insn; -} - -static int reloc_insn_movw(enum aarch64_reloc_op op, void *place, u64 val, - int lsb, enum aarch64_imm_type imm_type) -{ - u64 imm, limit = 0; - s64 sval; - u32 insn = *(u32 *)place; - - sval = do_reloc(op, place, val); - sval >>= lsb; - imm = sval & 0xffff; - /* Update the instruction with the new encoding. */ - *(u32 *)place = encode_insn_immediate(imm_type, insn, imm); - - /* Shift out the immediate field. */ - sval >>= 16; + insn = aarch64_insn_encode_immediate(AARCH64_INSN_IMM_16, insn, imm); + WRITE_PLACE(place, cpu_to_le32(insn), me); - /* - * For unsigned immediates, the overflow check is straightforward. - * For signed immediates, the sign bit is actually the bit past the - * most significant bit of the field. - * The INSN_IMM_16 immediate type is unsigned. - */ - if (imm_type != INSN_IMM_16) { - sval++; - limit++; - } - - /* Check the upper bits depending on the sign of the immediate. */ - if ((u64)sval > limit) + if (imm > U16_MAX) return -ERANGE; return 0; } -static int reloc_insn_imm(enum aarch64_reloc_op op, void *place, u64 val, - int lsb, int len, enum aarch64_imm_type imm_type) +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, + struct module *me) { u64 imm, imm_mask; s64 sval; - u32 insn = *(u32 *)place; + u32 insn = le32_to_cpu(*place); /* Calculate the relocation value. */ sval = do_reloc(op, place, val); @@ -233,7 +182,8 @@ static int reloc_insn_imm(enum aarch64_reloc_op op, void *place, u64 val, imm = sval & imm_mask; /* Update the instruction's immediate field. */ - *(u32 *)place = encode_insn_immediate(imm_type, insn, imm); + insn = aarch64_insn_encode_immediate(imm_type, insn, imm); + WRITE_PLACE(place, cpu_to_le32(insn), me); /* * Extract the upper value bits (including the sign bit) and @@ -251,6 +201,33 @@ static int reloc_insn_imm(enum aarch64_reloc_op op, void *place, u64 val, return 0; } +static int reloc_insn_adrp(struct module *mod, Elf64_Shdr *sechdrs, + __le32 *place, u64 val, struct module *me) +{ + u32 insn; + + if (!is_forbidden_offset_for_adrp(place)) + return reloc_insn_imm(RELOC_OP_PAGE, place, val, 12, 21, + AARCH64_INSN_IMM_ADR, me); + + /* 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, me)) { + insn = le32_to_cpu(*place); + insn &= ~BIT(31); + } else { + /* out of range for ADR -> emit a veneer */ + val = module_emit_veneer_for_adrp(mod, sechdrs, place, val & ~0xfff); + if (!val) + return -ENOEXEC; + insn = aarch64_insn_gen_branch_imm((u64)place, val, + AARCH64_INSN_BRANCH_NOLINK); + } + + WRITE_PLACE(place, cpu_to_le32(insn), me); + return 0; +} + int apply_relocate_add(Elf64_Shdr *sechdrs, const char *strtab, unsigned int symindex, @@ -291,149 +268,161 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, /* Data relocations. */ case R_AARCH64_ABS64: overflow_check = false; - ovf = reloc_data(RELOC_OP_ABS, loc, val, 64); + ovf = reloc_data(RELOC_OP_ABS, loc, val, 64, me); break; case R_AARCH64_ABS32: - ovf = reloc_data(RELOC_OP_ABS, loc, val, 32); + ovf = reloc_data(RELOC_OP_ABS, loc, val, 32, me); break; case R_AARCH64_ABS16: - ovf = reloc_data(RELOC_OP_ABS, loc, val, 16); + ovf = reloc_data(RELOC_OP_ABS, loc, val, 16, me); break; case R_AARCH64_PREL64: overflow_check = false; - ovf = reloc_data(RELOC_OP_PREL, loc, val, 64); + ovf = reloc_data(RELOC_OP_PREL, loc, val, 64, me); break; case R_AARCH64_PREL32: - ovf = reloc_data(RELOC_OP_PREL, loc, val, 32); + ovf = reloc_data(RELOC_OP_PREL, loc, val, 32, me); break; case R_AARCH64_PREL16: - ovf = reloc_data(RELOC_OP_PREL, loc, val, 16); + ovf = reloc_data(RELOC_OP_PREL, loc, val, 16, me); break; /* MOVW instruction relocations. */ case R_AARCH64_MOVW_UABS_G0_NC: overflow_check = false; + fallthrough; case R_AARCH64_MOVW_UABS_G0: ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 0, - INSN_IMM_16); + AARCH64_INSN_IMM_MOVKZ, me); break; case R_AARCH64_MOVW_UABS_G1_NC: overflow_check = false; + fallthrough; case R_AARCH64_MOVW_UABS_G1: ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 16, - INSN_IMM_16); + AARCH64_INSN_IMM_MOVKZ, me); break; case R_AARCH64_MOVW_UABS_G2_NC: overflow_check = false; + fallthrough; case R_AARCH64_MOVW_UABS_G2: ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 32, - INSN_IMM_16); + AARCH64_INSN_IMM_MOVKZ, me); 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, - INSN_IMM_16); + AARCH64_INSN_IMM_MOVKZ, me); break; case R_AARCH64_MOVW_SABS_G0: ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 0, - INSN_IMM_MOVNZ); + AARCH64_INSN_IMM_MOVNZ, me); break; case R_AARCH64_MOVW_SABS_G1: ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 16, - INSN_IMM_MOVNZ); + AARCH64_INSN_IMM_MOVNZ, me); break; case R_AARCH64_MOVW_SABS_G2: ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 32, - INSN_IMM_MOVNZ); + AARCH64_INSN_IMM_MOVNZ, me); break; case R_AARCH64_MOVW_PREL_G0_NC: overflow_check = false; ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 0, - INSN_IMM_MOVK); + AARCH64_INSN_IMM_MOVKZ, me); break; case R_AARCH64_MOVW_PREL_G0: ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 0, - INSN_IMM_MOVNZ); + AARCH64_INSN_IMM_MOVNZ, me); break; case R_AARCH64_MOVW_PREL_G1_NC: overflow_check = false; ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 16, - INSN_IMM_MOVK); + AARCH64_INSN_IMM_MOVKZ, me); break; case R_AARCH64_MOVW_PREL_G1: ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 16, - INSN_IMM_MOVNZ); + AARCH64_INSN_IMM_MOVNZ, me); break; case R_AARCH64_MOVW_PREL_G2_NC: overflow_check = false; ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 32, - INSN_IMM_MOVK); + AARCH64_INSN_IMM_MOVKZ, me); break; case R_AARCH64_MOVW_PREL_G2: ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 32, - INSN_IMM_MOVNZ); + AARCH64_INSN_IMM_MOVNZ, me); 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, - INSN_IMM_MOVNZ); + AARCH64_INSN_IMM_MOVNZ, me); break; /* Immediate instruction relocations. */ case R_AARCH64_LD_PREL_LO19: ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 19, - INSN_IMM_19); + AARCH64_INSN_IMM_19, me); break; case R_AARCH64_ADR_PREL_LO21: ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 0, 21, - INSN_IMM_ADR); + AARCH64_INSN_IMM_ADR, me); break; case R_AARCH64_ADR_PREL_PG_HI21_NC: overflow_check = false; + fallthrough; case R_AARCH64_ADR_PREL_PG_HI21: - ovf = reloc_insn_imm(RELOC_OP_PAGE, loc, val, 12, 21, - INSN_IMM_ADR); + ovf = reloc_insn_adrp(me, sechdrs, loc, val, me); + 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, - INSN_IMM_12); + AARCH64_INSN_IMM_12, me); break; case R_AARCH64_LDST16_ABS_LO12_NC: overflow_check = false; ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 1, 11, - INSN_IMM_12); + AARCH64_INSN_IMM_12, me); break; case R_AARCH64_LDST32_ABS_LO12_NC: overflow_check = false; ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 2, 10, - INSN_IMM_12); + AARCH64_INSN_IMM_12, me); break; case R_AARCH64_LDST64_ABS_LO12_NC: overflow_check = false; ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 3, 9, - INSN_IMM_12); + AARCH64_INSN_IMM_12, me); break; case R_AARCH64_LDST128_ABS_LO12_NC: overflow_check = false; ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 4, 8, - INSN_IMM_12); + AARCH64_INSN_IMM_12, me); break; case R_AARCH64_TSTBR14: ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 14, - INSN_IMM_14); + AARCH64_INSN_IMM_14, me); break; case R_AARCH64_CONDBR19: ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 19, - INSN_IMM_19); + AARCH64_INSN_IMM_19, me); break; case R_AARCH64_JUMP26: case R_AARCH64_CALL26: ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 26, - INSN_IMM_26); + AARCH64_INSN_IMM_26, me); + if (ovf == -ERANGE) { + val = module_emit_plt_entry(me, sechdrs, loc, &rel[i], sym); + if (!val) + return -ENOEXEC; + ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, + 26, AARCH64_INSN_IMM_26, me); + } break; default: @@ -454,3 +443,77 @@ overflow: me->name, (int)ELF64_R_TYPE(rel[i].r_info), val); return -ENOEXEC; } + +static inline void __init_plt(struct plt_entry *plt, unsigned long addr) +{ + *plt = get_plt_entry(addr, plt); +} + +static int module_init_ftrace_plt(const Elf_Ehdr *hdr, + const Elf_Shdr *sechdrs, + struct module *mod) +{ +#if defined(CONFIG_DYNAMIC_FTRACE) + const Elf_Shdr *s; + struct plt_entry *plts; + + s = find_section(hdr, sechdrs, ".text.ftrace_trampoline"); + if (!s) + return -ENOEXEC; + + plts = (void *)s->sh_addr; + + __init_plt(&plts[FTRACE_PLT_IDX], FTRACE_ADDR); + + mod->arch.ftrace_trampolines = plts; + + s = find_section(hdr, sechdrs, ".init.text.ftrace_trampoline"); + if (!s) + return -ENOEXEC; + + plts = (void *)s->sh_addr; + + __init_plt(&plts[FTRACE_PLT_IDX], FTRACE_ADDR); + + mod->arch.init_ftrace_trampolines = plts; + +#endif + return 0; +} + +int module_finalize(const Elf_Ehdr *hdr, + const Elf_Shdr *sechdrs, + struct module *me) +{ + const Elf_Shdr *s; + int ret; + + s = find_section(hdr, sechdrs, ".altinstructions"); + if (s) { + ret = apply_alternatives_module((void *)s->sh_addr, s->sh_size); + if (ret < 0) { + pr_err("module %s: error occurred when applying alternatives\n", me->name); + return ret; + } + } + + if (scs_is_dynamic()) { + s = find_section(hdr, sechdrs, ".init.eh_frame"); + if (s) { + /* + * Because we can reject modules that are malformed + * so SCS patching fails, skip dry run and try to patch + * it in place. If patching fails, the module would not + * be loaded anyway. + */ + ret = __pi_scs_patch((void *)s->sh_addr, s->sh_size, true); + if (ret) { + pr_err("module %s: error occurred during dynamic SCS patching (%d)\n", + me->name, ret); + return -ENOEXEC; + } + } + } + + return module_init_ftrace_plt(hdr, sechdrs, me); +} |