diff options
Diffstat (limited to 'arch/arm64/kernel/module.c')
| -rw-r--r-- | arch/arm64/kernel/module.c | 289 |
1 files changed, 174 insertions, 115 deletions
diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c index f713e2fc4d75..24adb581af0e 100644 --- a/arch/arm64/kernel/module.c +++ b/arch/arm64/kernel/module.c @@ -1,72 +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> + #include <asm/alternative.h> #include <asm/insn.h> +#include <asm/scs.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; -} +#include <asm/text-patching.h> enum aarch64_reloc_op { RELOC_OP_NONE, @@ -92,23 +49,67 @@ static u64 do_reloc(enum aarch64_reloc_op reloc_op, __le32 *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) { 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; - if (sval < S16_MIN || sval > U16_MAX) - return -ERANGE; + 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; - if (sval < S32_MIN || sval > U32_MAX) - return -ERANGE; + 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); @@ -123,7 +124,8 @@ enum aarch64_insn_movw_imm_type { }; static int reloc_insn_movw(enum aarch64_reloc_op op, __le32 *place, u64 val, - int lsb, enum aarch64_insn_movw_imm_type imm_type) + int lsb, enum aarch64_insn_movw_imm_type imm_type, + struct module *me) { u64 imm; s64 sval; @@ -155,7 +157,7 @@ static int reloc_insn_movw(enum aarch64_reloc_op op, __le32 *place, u64 val, /* Update the instruction with the new encoding. */ insn = aarch64_insn_encode_immediate(AARCH64_INSN_IMM_16, insn, imm); - *place = cpu_to_le32(insn); + WRITE_PLACE(place, cpu_to_le32(insn), me); if (imm > U16_MAX) return -ERANGE; @@ -164,7 +166,8 @@ static int reloc_insn_movw(enum aarch64_reloc_op op, __le32 *place, u64 val, } 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) + int lsb, int len, enum aarch64_insn_imm_type imm_type, + struct module *me) { u64 imm, imm_mask; s64 sval; @@ -180,7 +183,7 @@ static int reloc_insn_imm(enum aarch64_reloc_op op, __le32 *place, u64 val, /* Update the instruction's immediate field. */ insn = aarch64_insn_encode_immediate(imm_type, insn, imm); - *place = cpu_to_le32(insn); + WRITE_PLACE(place, cpu_to_le32(insn), me); /* * Extract the upper value bits (including the sign bit) and @@ -199,17 +202,17 @@ static int reloc_insn_imm(enum aarch64_reloc_op op, __le32 *place, u64 val, } static int reloc_insn_adrp(struct module *mod, Elf64_Shdr *sechdrs, - __le32 *place, u64 val) + __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); + 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)) { + AARCH64_INSN_IMM_ADR, me)) { insn = le32_to_cpu(*place); insn &= ~BIT(31); } else { @@ -221,7 +224,7 @@ static int reloc_insn_adrp(struct module *mod, Elf64_Shdr *sechdrs, AARCH64_INSN_BRANCH_NOLINK); } - *place = cpu_to_le32(insn); + WRITE_PLACE(place, cpu_to_le32(insn), me); return 0; } @@ -265,109 +268,113 @@ 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, - AARCH64_INSN_IMM_MOVKZ); + 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, - AARCH64_INSN_IMM_MOVKZ); + 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, - AARCH64_INSN_IMM_MOVKZ); + 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, - AARCH64_INSN_IMM_MOVKZ); + AARCH64_INSN_IMM_MOVKZ, me); break; case R_AARCH64_MOVW_SABS_G0: ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 0, - AARCH64_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, - AARCH64_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, - AARCH64_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, - AARCH64_INSN_IMM_MOVKZ); + AARCH64_INSN_IMM_MOVKZ, me); break; case R_AARCH64_MOVW_PREL_G0: ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 0, - AARCH64_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, - AARCH64_INSN_IMM_MOVKZ); + AARCH64_INSN_IMM_MOVKZ, me); break; case R_AARCH64_MOVW_PREL_G1: ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 16, - AARCH64_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, - AARCH64_INSN_IMM_MOVKZ); + AARCH64_INSN_IMM_MOVKZ, me); break; case R_AARCH64_MOVW_PREL_G2: ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 32, - AARCH64_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, - AARCH64_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, - AARCH64_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, - AARCH64_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_adrp(me, sechdrs, loc, val); + ovf = reloc_insn_adrp(me, sechdrs, loc, val, me); if (ovf && ovf != -ERANGE) return ovf; break; @@ -375,48 +382,46 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, 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); + 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, - AARCH64_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, - AARCH64_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, - AARCH64_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, - AARCH64_INSN_IMM_12); + AARCH64_INSN_IMM_12, me); break; case R_AARCH64_TSTBR14: ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 14, - AARCH64_INSN_IMM_14); + AARCH64_INSN_IMM_14, me); break; case R_AARCH64_CONDBR19: ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 19, - AARCH64_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, - AARCH64_INSN_IMM_26); - - if (IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) && - ovf == -ERANGE) { + 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); + 26, AARCH64_INSN_IMM_26, me); } break; @@ -439,22 +444,76 @@ overflow: 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, *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_module((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 + 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; + } } - return 0; + 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); } |