diff options
Diffstat (limited to 'tools/objtool/arch/x86')
| -rw-r--r-- | tools/objtool/arch/x86/Build | 14 | ||||
| -rw-r--r-- | tools/objtool/arch/x86/decode.c | 318 | ||||
| -rw-r--r-- | tools/objtool/arch/x86/include/arch/elf.h | 11 | ||||
| -rw-r--r-- | tools/objtool/arch/x86/include/arch/special.h | 6 | ||||
| -rw-r--r-- | tools/objtool/arch/x86/orc.c | 187 | ||||
| -rw-r--r-- | tools/objtool/arch/x86/special.c | 87 |
6 files changed, 485 insertions, 138 deletions
diff --git a/tools/objtool/arch/x86/Build b/tools/objtool/arch/x86/Build index 9f7869b5c5e0..febee0b8ee0b 100644 --- a/tools/objtool/arch/x86/Build +++ b/tools/objtool/arch/x86/Build @@ -1,5 +1,6 @@ -objtool-y += special.o objtool-y += decode.o +objtool-y += special.o +objtool-y += orc.o inat_tables_script = ../arch/x86/tools/gen-insn-attr-x86.awk inat_tables_maps = ../arch/x86/lib/x86-opcode-map.txt @@ -11,3 +12,14 @@ $(OUTPUT)arch/x86/lib/inat-tables.c: $(inat_tables_script) $(inat_tables_maps) $(OUTPUT)arch/x86/decode.o: $(OUTPUT)arch/x86/lib/inat-tables.c CFLAGS_decode.o += -I$(OUTPUT)arch/x86/lib + +cpu_features = ../arch/x86/include/asm/cpufeatures.h +cpu_features_script = ../arch/x86/tools/gen-cpu-feature-names-x86.awk + +$(OUTPUT)arch/x86/lib/cpu-feature-names.c: $(cpu_features_script) $(cpu_features) + $(call rule_mkdir) + $(Q)$(call echo-cmd,gen)$(AWK) -f $(cpu_features_script) $(cpu_features) > $@ + +$(OUTPUT)arch/x86/special.o: $(OUTPUT)arch/x86/lib/cpu-feature-names.c + +CFLAGS_special.o += -I$(OUTPUT)arch/x86/lib diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c index e7b030f7e2a5..f4af82508228 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -16,14 +16,22 @@ #include <asm/orc_types.h> #include <objtool/check.h> +#include <objtool/disas.h> #include <objtool/elf.h> #include <objtool/arch.h> #include <objtool/warn.h> -#include <objtool/endianness.h> #include <objtool/builtin.h> #include <arch/elf.h> -int arch_ftrace_match(char *name) +const char *arch_reg_name[CFI_NUM_REGS] = { + "rax", "rcx", "rdx", "rbx", + "rsp", "rbp", "rsi", "rdi", + "r8", "r9", "r10", "r11", + "r12", "r13", "r14", "r15", + "ra" +}; + +int arch_ftrace_match(const char *name) { return !strcmp(name, "__fentry__"); } @@ -36,7 +44,7 @@ static int is_x86_64(const struct elf *elf) case EM_386: return 0; default: - WARN("unexpected ELF machine type %d", elf->ehdr.e_machine); + ERROR("unexpected ELF machine type %d", elf->ehdr.e_machine); return -1; } } @@ -68,9 +76,65 @@ bool arch_callee_saved_reg(unsigned char reg) } } -unsigned long arch_dest_reloc_offset(int addend) +/* Undo the effects of __pa_symbol() if necessary */ +static unsigned long phys_to_virt(unsigned long pa) +{ + s64 va = pa; + + if (va > 0) + va &= ~(0x80000000); + + return va; +} + +s64 arch_insn_adjusted_addend(struct instruction *insn, struct reloc *reloc) +{ + s64 addend = reloc_addend(reloc); + + if (arch_pc_relative_reloc(reloc)) + addend += insn->offset + insn->len - reloc_offset(reloc); + + return phys_to_virt(addend); +} + +static void scan_for_insn(struct section *sec, unsigned long offset, + unsigned long *insn_off, unsigned int *insn_len) +{ + unsigned long o = 0; + struct insn insn; + + while (1) { + + insn_decode(&insn, sec->data->d_buf + o, sec_size(sec) - o, + INSN_MODE_64); + + if (o + insn.length > offset) { + *insn_off = o; + *insn_len = insn.length; + return; + } + + o += insn.length; + } +} + +u64 arch_adjusted_addend(struct reloc *reloc) { - return addend + 4; + unsigned int type = reloc_type(reloc); + s64 addend = reloc_addend(reloc); + unsigned long insn_off; + unsigned int insn_len; + + if (type == R_X86_64_PLT32) + return addend + 4; + + if (type != R_X86_64_PC32 || !is_text_sec(reloc->sec->base)) + return addend; + + scan_for_insn(reloc->sec->base, reloc_offset(reloc), + &insn_off, &insn_len); + + return addend + insn_off + insn_len - reloc_offset(reloc); } unsigned long arch_jump_destination(struct instruction *insn) @@ -84,7 +148,7 @@ bool arch_pc_relative_reloc(struct reloc *reloc) * All relocation types where P (the address of the target) * is included in the computation. */ - switch (reloc->type) { + switch (reloc_type(reloc)) { case R_X86_64_PC8: case R_X86_64_PC16: case R_X86_64_PC32: @@ -105,7 +169,7 @@ bool arch_pc_relative_reloc(struct reloc *reloc) #define ADD_OP(op) \ if (!(op = calloc(1, sizeof(*op)))) \ return -1; \ - else for (list_add_tail(&op->list, ops_list); op; op = NULL) + else for (*ops_list = op, ops_list = &op->next; op; op = NULL) /* * Helpers to decode ModRM/SIB: @@ -125,8 +189,14 @@ bool arch_pc_relative_reloc(struct reloc *reloc) #define is_RIP() ((modrm_rm & 7) == CFI_BP && modrm_mod == 0) #define have_SIB() ((modrm_rm & 7) == CFI_SP && mod_is_mem()) +/* + * Check the ModRM register. If there is a SIB byte then check with + * the SIB base register. But if the SIB base is 5 (i.e. CFI_BP) and + * ModRM mod is 0 then there is no base register. + */ #define rm_is(reg) (have_SIB() ? \ - sib_base == (reg) && sib_index == CFI_SP : \ + sib_base == (reg) && sib_index == CFI_SP && \ + (sib_base != CFI_BP || modrm_mod != 0) : \ modrm_rm == (reg)) #define rm_is_mem(reg) (mod_is_mem() && !is_RIP() && rm_is(reg)) @@ -146,12 +216,11 @@ static bool has_notrack_prefix(struct insn *insn) int arch_decode_instruction(struct objtool_file *file, const struct section *sec, unsigned long offset, unsigned int maxlen, - unsigned int *len, enum insn_type *type, - unsigned long *immediate, - struct list_head *ops_list) + struct instruction *insn) { + struct stack_op **ops_list = &insn->stack_ops; const struct elf *elf = file->elf; - struct insn insn; + struct insn ins; int x86_64, ret; unsigned char op1, op2, op3, prefix, rex = 0, rex_b = 0, rex_r = 0, rex_w = 0, rex_x = 0, @@ -165,42 +234,42 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec if (x86_64 == -1) return -1; - ret = insn_decode(&insn, sec->data->d_buf + offset, maxlen, + ret = insn_decode(&ins, sec->data->d_buf + offset, maxlen, x86_64 ? INSN_MODE_64 : INSN_MODE_32); if (ret < 0) { - WARN("can't decode instruction at %s:0x%lx", sec->name, offset); + ERROR("can't decode instruction at %s:0x%lx", sec->name, offset); return -1; } - *len = insn.length; - *type = INSN_OTHER; + insn->len = ins.length; + insn->type = INSN_OTHER; - if (insn.vex_prefix.nbytes) + if (ins.vex_prefix.nbytes) return 0; - prefix = insn.prefixes.bytes[0]; + prefix = ins.prefixes.bytes[0]; - op1 = insn.opcode.bytes[0]; - op2 = insn.opcode.bytes[1]; - op3 = insn.opcode.bytes[2]; + op1 = ins.opcode.bytes[0]; + op2 = ins.opcode.bytes[1]; + op3 = ins.opcode.bytes[2]; - if (insn.rex_prefix.nbytes) { - rex = insn.rex_prefix.bytes[0]; + if (ins.rex_prefix.nbytes) { + rex = ins.rex_prefix.bytes[0]; rex_w = X86_REX_W(rex) >> 3; rex_r = X86_REX_R(rex) >> 2; rex_x = X86_REX_X(rex) >> 1; rex_b = X86_REX_B(rex); } - if (insn.modrm.nbytes) { - modrm = insn.modrm.bytes[0]; + if (ins.modrm.nbytes) { + modrm = ins.modrm.bytes[0]; modrm_mod = X86_MODRM_MOD(modrm); modrm_reg = X86_MODRM_REG(modrm) + 8*rex_r; modrm_rm = X86_MODRM_RM(modrm) + 8*rex_b; } - if (insn.sib.nbytes) { - sib = insn.sib.bytes[0]; + if (ins.sib.nbytes) { + sib = ins.sib.bytes[0]; /* sib_scale = X86_SIB_SCALE(sib); */ sib_index = X86_SIB_INDEX(sib) + 8*rex_x; sib_base = X86_SIB_BASE(sib) + 8*rex_b; @@ -254,7 +323,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec break; case 0x70 ... 0x7f: - *type = INSN_JUMP_CONDITIONAL; + insn->type = INSN_JUMP_CONDITIONAL; break; case 0x80 ... 0x83: @@ -278,7 +347,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec if (!rm_is_reg(CFI_SP)) break; - imm = insn.immediate.value; + imm = ins.immediate.value; if (op1 & 2) { /* sign extend */ if (op1 & 1) { /* imm32 */ imm <<= 32; @@ -292,7 +361,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec switch (modrm_reg & 7) { case 5: imm = -imm; - /* fallthrough */ + fallthrough; case 0: /* add/sub imm, %rsp */ ADD_OP(op) { @@ -309,14 +378,14 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec ADD_OP(op) { op->src.type = OP_SRC_AND; op->src.reg = CFI_SP; - op->src.offset = insn.immediate.value; + op->src.offset = ins.immediate.value; op->dest.type = OP_DEST_REG; op->dest.reg = CFI_SP; } break; default: - /* WARN ? */ + /* ERROR ? */ break; } @@ -356,7 +425,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec op->src.reg = CFI_SP; op->dest.type = OP_DEST_REG_INDIRECT; op->dest.reg = modrm_rm; - op->dest.offset = insn.displacement.value; + op->dest.offset = ins.displacement.value; } break; } @@ -376,7 +445,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec break; } - /* fallthrough */ + fallthrough; case 0x88: if (!rex_w) break; @@ -389,7 +458,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec op->src.reg = modrm_reg; op->dest.type = OP_DEST_REG_INDIRECT; op->dest.reg = CFI_BP; - op->dest.offset = insn.displacement.value; + op->dest.offset = ins.displacement.value; } break; } @@ -402,7 +471,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec op->src.reg = modrm_reg; op->dest.type = OP_DEST_REG_INDIRECT; op->dest.reg = CFI_SP; - op->dest.offset = insn.displacement.value; + op->dest.offset = ins.displacement.value; } break; } @@ -419,7 +488,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec ADD_OP(op) { op->src.type = OP_SRC_REG_INDIRECT; op->src.reg = CFI_BP; - op->src.offset = insn.displacement.value; + op->src.offset = ins.displacement.value; op->dest.type = OP_DEST_REG; op->dest.reg = modrm_reg; } @@ -432,7 +501,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec ADD_OP(op) { op->src.type = OP_SRC_REG_INDIRECT; op->src.reg = CFI_SP; - op->src.offset = insn.displacement.value; + op->src.offset = ins.displacement.value; op->dest.type = OP_DEST_REG; op->dest.reg = modrm_reg; } @@ -451,10 +520,6 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec if (!rex_w) break; - /* skip RIP relative displacement */ - if (is_RIP()) - break; - /* skip nontrivial SIB */ if (have_SIB()) { modrm_rm = sib_base; @@ -462,9 +527,15 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec break; } + /* lea disp(%rip), %dst */ + if (is_RIP()) { + insn->type = INSN_LEA_RIP; + break; + } + /* lea disp(%src), %dst */ ADD_OP(op) { - op->src.offset = insn.displacement.value; + op->src.offset = ins.displacement.value; if (!op->src.offset) { /* lea (%src), %dst */ op->src.type = OP_SRC_REG; @@ -487,7 +558,13 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec break; case 0x90: - *type = INSN_NOP; + if (rex_b) /* XCHG %r8, %rax */ + break; + + if (prefix == 0xf3) /* REP NOP := PAUSE */ + break; + + insn->type = INSN_NOP; break; case 0x9c: @@ -510,43 +587,56 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec if (op2 == 0x01) { - if (modrm == 0xca) - *type = INSN_CLAC; - else if (modrm == 0xcb) - *type = INSN_STAC; - + switch (insn_last_prefix_id(&ins)) { + case INAT_PFX_REPE: + case INAT_PFX_REPNE: + if (modrm == 0xca) + /* eretu/erets */ + insn->type = INSN_SYSRET; + break; + default: + if (modrm == 0xca) + insn->type = INSN_CLAC; + else if (modrm == 0xcb) + insn->type = INSN_STAC; + break; + } } else if (op2 >= 0x80 && op2 <= 0x8f) { - *type = INSN_JUMP_CONDITIONAL; + insn->type = INSN_JUMP_CONDITIONAL; + + } else if (op2 == 0x05 || op2 == 0x34) { + + /* syscall, sysenter */ + insn->type = INSN_SYSCALL; - } else if (op2 == 0x05 || op2 == 0x07 || op2 == 0x34 || - op2 == 0x35) { + } else if (op2 == 0x07 || op2 == 0x35) { - /* sysenter, sysret */ - *type = INSN_CONTEXT_SWITCH; + /* sysret, sysexit */ + insn->type = INSN_SYSRET; } else if (op2 == 0x0b || op2 == 0xb9) { - /* ud2 */ - *type = INSN_BUG; + /* ud2, ud1 */ + insn->type = INSN_BUG; - } else if (op2 == 0x0d || op2 == 0x1f) { + } else if (op2 == 0x1f) { - /* nopl/nopw */ - *type = INSN_NOP; + /* 0f 1f /0 := NOPL */ + if (modrm_reg == 0) + insn->type = INSN_NOP; } else if (op2 == 0x1e) { if (prefix == 0xf3 && (modrm == 0xfa || modrm == 0xfb)) - *type = INSN_ENDBR; + insn->type = INSN_ENDBR; } else if (op2 == 0x38 && op3 == 0xf8) { - if (insn.prefixes.nbytes == 1 && - insn.prefixes.bytes[0] == 0xf2) { + if (ins.prefixes.nbytes == 1 && + ins.prefixes.bytes[0] == 0xf2) { /* ENQCMD cannot be used in the kernel. */ - WARN("ENQCMD instruction at %s:%lx", sec->name, - offset); + WARN("ENQCMD instruction at %s:%lx", sec->name, offset); } } else if (op2 == 0xa0 || op2 == 0xa8) { @@ -591,29 +681,29 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec case 0xcc: /* int3 */ - *type = INSN_TRAP; + insn->type = INSN_TRAP; break; case 0xe3: /* jecxz/jrcxz */ - *type = INSN_JUMP_CONDITIONAL; + insn->type = INSN_JUMP_CONDITIONAL; break; case 0xe9: case 0xeb: - *type = INSN_JUMP_UNCONDITIONAL; + insn->type = INSN_JUMP_UNCONDITIONAL; break; case 0xc2: case 0xc3: - *type = INSN_RETURN; + insn->type = INSN_RETURN; break; case 0xc7: /* mov imm, r/m */ if (!opts.noinstr) break; - if (insn.length == 3+4+4 && !strncmp(sec->name, ".init.text", 10)) { + if (ins.length == 3+4+4 && !strncmp(sec->name, ".init.text", 10)) { struct reloc *immr, *disp; struct symbol *func; int idx; @@ -624,13 +714,13 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec if (!immr || strcmp(immr->sym->name, "pv_ops")) break; - idx = (immr->addend + 8) / sizeof(void *); + idx = (reloc_addend(immr) + 8) / sizeof(void *); func = disp->sym; if (disp->sym->type == STT_SECTION) - func = find_symbol_by_offset(disp->sym->sec, disp->addend); + func = find_symbol_by_offset(disp->sym->sec, reloc_addend(disp)); if (!func) { - WARN("no func for pv_ops[]"); + ERROR("no func for pv_ops[]"); return -1; } @@ -657,21 +747,25 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec break; } - /* fallthrough */ + fallthrough; case 0xca: /* retf */ case 0xcb: /* retf */ - *type = INSN_CONTEXT_SWITCH; + insn->type = INSN_SYSRET; + break; + + case 0xd6: /* udb */ + insn->type = INSN_BUG; break; case 0xe0: /* loopne */ case 0xe1: /* loope */ case 0xe2: /* loop */ - *type = INSN_JUMP_CONDITIONAL; + insn->type = INSN_JUMP_CONDITIONAL; break; case 0xe8: - *type = INSN_CALL; + insn->type = INSN_CALL; /* * For the impact on the stack, a CALL behaves like * a PUSH of an immediate value (the return address). @@ -683,30 +777,30 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec break; case 0xfc: - *type = INSN_CLD; + insn->type = INSN_CLD; break; case 0xfd: - *type = INSN_STD; + insn->type = INSN_STD; break; case 0xff: if (modrm_reg == 2 || modrm_reg == 3) { - *type = INSN_CALL_DYNAMIC; - if (has_notrack_prefix(&insn)) + insn->type = INSN_CALL_DYNAMIC; + if (has_notrack_prefix(&ins)) WARN("notrack prefix found at %s:0x%lx", sec->name, offset); } else if (modrm_reg == 4) { - *type = INSN_JUMP_DYNAMIC; - if (has_notrack_prefix(&insn)) + insn->type = INSN_JUMP_DYNAMIC; + if (has_notrack_prefix(&ins)) WARN("notrack prefix found at %s:0x%lx", sec->name, offset); } else if (modrm_reg == 5) { /* jmpf */ - *type = INSN_CONTEXT_SWITCH; + insn->type = INSN_SYSRET; } else if (modrm_reg == 6) { @@ -723,7 +817,10 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec break; } - *immediate = insn.immediate.nbytes ? insn.immediate.value : 0; + if (ins.immediate.nbytes) + insn->immediate = ins.immediate.value; + else if (ins.displacement.nbytes) + insn->immediate = ins.displacement.value; return 0; } @@ -757,7 +854,7 @@ const char *arch_nop_insn(int len) }; if (len < 1 || len > 5) { - WARN("invalid NOP size: %d\n", len); + ERROR("invalid NOP size: %d\n", len); return NULL; } @@ -777,7 +874,7 @@ const char *arch_ret_insn(int len) }; if (len < 1 || len > 5) { - WARN("invalid RET size: %d\n", len); + ERROR("invalid RET size: %d\n", len); return NULL; } @@ -820,10 +917,55 @@ int arch_decode_hint_reg(u8 sp_reg, int *base) bool arch_is_retpoline(struct symbol *sym) { - return !strncmp(sym->name, "__x86_indirect_", 15); + return !strncmp(sym->name, "__x86_indirect_", 15) || + !strncmp(sym->name, "__pi___x86_indirect_", 20); } bool arch_is_rethunk(struct symbol *sym) { - return !strcmp(sym->name, "__x86_return_thunk"); + return !strcmp(sym->name, "__x86_return_thunk") || + !strcmp(sym->name, "__pi___x86_return_thunk"); +} + +bool arch_is_embedded_insn(struct symbol *sym) +{ + return !strcmp(sym->name, "retbleed_return_thunk") || + !strcmp(sym->name, "srso_alias_safe_ret") || + !strcmp(sym->name, "srso_safe_ret"); } + +unsigned int arch_reloc_size(struct reloc *reloc) +{ + switch (reloc_type(reloc)) { + case R_X86_64_32: + case R_X86_64_32S: + case R_X86_64_PC32: + case R_X86_64_PLT32: + return 4; + default: + return 8; + } +} + +bool arch_absolute_reloc(struct elf *elf, struct reloc *reloc) +{ + switch (reloc_type(reloc)) { + case R_X86_64_32: + case R_X86_64_32S: + case R_X86_64_64: + return true; + default: + return false; + } +} + +#ifdef DISAS + +int arch_disas_info_init(struct disassemble_info *dinfo) +{ + return disas_info_init(dinfo, bfd_arch_i386, + bfd_mach_i386_i386, bfd_mach_x86_64, + "att"); +} + +#endif /* DISAS */ diff --git a/tools/objtool/arch/x86/include/arch/elf.h b/tools/objtool/arch/x86/include/arch/elf.h index ac14987cf687..7131f7f51a4e 100644 --- a/tools/objtool/arch/x86/include/arch/elf.h +++ b/tools/objtool/arch/x86/include/arch/elf.h @@ -1,8 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ #ifndef _OBJTOOL_ARCH_ELF #define _OBJTOOL_ARCH_ELF -#define R_NONE R_X86_64_NONE -#define R_ABS64 R_X86_64_64 -#define R_ABS32 R_X86_64_32 +#define R_NONE R_X86_64_NONE +#define R_ABS32 R_X86_64_32 +#define R_ABS64 R_X86_64_64 +#define R_DATA32 R_X86_64_PC32 +#define R_DATA64 R_X86_64_PC32 +#define R_TEXT32 R_X86_64_PC32 +#define R_TEXT64 R_X86_64_PC32 #endif /* _OBJTOOL_ARCH_ELF */ diff --git a/tools/objtool/arch/x86/include/arch/special.h b/tools/objtool/arch/x86/include/arch/special.h index f2918f789a0a..ca8131352994 100644 --- a/tools/objtool/arch/x86/include/arch/special.h +++ b/tools/objtool/arch/x86/include/arch/special.h @@ -11,11 +11,11 @@ #define JUMP_NEW_OFFSET 4 #define JUMP_KEY_OFFSET 8 -#define ALT_ENTRY_SIZE 12 +#define ALT_ENTRY_SIZE 14 #define ALT_ORIG_OFFSET 0 #define ALT_NEW_OFFSET 4 #define ALT_FEATURE_OFFSET 8 -#define ALT_ORIG_LEN_OFFSET 10 -#define ALT_NEW_LEN_OFFSET 11 +#define ALT_ORIG_LEN_OFFSET 12 +#define ALT_NEW_LEN_OFFSET 13 #endif /* _X86_ARCH_SPECIAL_H */ diff --git a/tools/objtool/arch/x86/orc.c b/tools/objtool/arch/x86/orc.c new file mode 100644 index 000000000000..735e150ca6b7 --- /dev/null +++ b/tools/objtool/arch/x86/orc.c @@ -0,0 +1,187 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +#include <linux/objtool_types.h> +#include <asm/orc_types.h> + +#include <objtool/check.h> +#include <objtool/orc.h> +#include <objtool/warn.h> + +int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruction *insn) +{ + struct cfi_reg *bp = &cfi->regs[CFI_BP]; + + memset(orc, 0, sizeof(*orc)); + + if (!cfi) { + /* + * This is usually either unreachable nops/traps (which don't + * trigger unreachable instruction warnings), or + * STACK_FRAME_NON_STANDARD functions. + */ + orc->type = ORC_TYPE_UNDEFINED; + return 0; + } + + switch (cfi->type) { + case UNWIND_HINT_TYPE_UNDEFINED: + orc->type = ORC_TYPE_UNDEFINED; + return 0; + case UNWIND_HINT_TYPE_END_OF_STACK: + orc->type = ORC_TYPE_END_OF_STACK; + return 0; + case UNWIND_HINT_TYPE_CALL: + orc->type = ORC_TYPE_CALL; + break; + case UNWIND_HINT_TYPE_REGS: + orc->type = ORC_TYPE_REGS; + break; + case UNWIND_HINT_TYPE_REGS_PARTIAL: + orc->type = ORC_TYPE_REGS_PARTIAL; + break; + default: + ERROR_INSN(insn, "unknown unwind hint type %d", cfi->type); + return -1; + } + + orc->signal = cfi->signal; + + switch (cfi->cfa.base) { + case CFI_SP: + orc->sp_reg = ORC_REG_SP; + break; + case CFI_SP_INDIRECT: + orc->sp_reg = ORC_REG_SP_INDIRECT; + break; + case CFI_BP: + orc->sp_reg = ORC_REG_BP; + break; + case CFI_BP_INDIRECT: + orc->sp_reg = ORC_REG_BP_INDIRECT; + break; + case CFI_R10: + orc->sp_reg = ORC_REG_R10; + break; + case CFI_R13: + orc->sp_reg = ORC_REG_R13; + break; + case CFI_DI: + orc->sp_reg = ORC_REG_DI; + break; + case CFI_DX: + orc->sp_reg = ORC_REG_DX; + break; + default: + ERROR_INSN(insn, "unknown CFA base reg %d", cfi->cfa.base); + return -1; + } + + switch (bp->base) { + case CFI_UNDEFINED: + orc->bp_reg = ORC_REG_UNDEFINED; + break; + case CFI_CFA: + orc->bp_reg = ORC_REG_PREV_SP; + break; + case CFI_BP: + orc->bp_reg = ORC_REG_BP; + break; + default: + ERROR_INSN(insn, "unknown BP base reg %d", bp->base); + return -1; + } + + orc->sp_offset = cfi->cfa.offset; + orc->bp_offset = bp->offset; + + return 0; +} + +int write_orc_entry(struct elf *elf, struct section *orc_sec, + struct section *ip_sec, unsigned int idx, + struct section *insn_sec, unsigned long insn_off, + struct orc_entry *o) +{ + struct orc_entry *orc; + + /* populate ORC data */ + orc = (struct orc_entry *)orc_sec->data->d_buf + idx; + memcpy(orc, o, sizeof(*orc)); + orc->sp_offset = bswap_if_needed(elf, orc->sp_offset); + orc->bp_offset = bswap_if_needed(elf, orc->bp_offset); + + /* populate reloc for ip */ + if (!elf_init_reloc_text_sym(elf, ip_sec, idx * sizeof(int), idx, + insn_sec, insn_off)) + return -1; + + return 0; +} + +static const char *reg_name(unsigned int reg) +{ + switch (reg) { + case ORC_REG_PREV_SP: + return "prevsp"; + case ORC_REG_DX: + return "dx"; + case ORC_REG_DI: + return "di"; + case ORC_REG_BP: + return "bp"; + case ORC_REG_SP: + return "sp"; + case ORC_REG_R10: + return "r10"; + case ORC_REG_R13: + return "r13"; + case ORC_REG_BP_INDIRECT: + return "bp(ind)"; + case ORC_REG_SP_INDIRECT: + return "sp(ind)"; + default: + return "?"; + } +} + +static const char *orc_type_name(unsigned int type) +{ + switch (type) { + case ORC_TYPE_UNDEFINED: + return "(und)"; + case ORC_TYPE_END_OF_STACK: + return "end"; + case ORC_TYPE_CALL: + return "call"; + case ORC_TYPE_REGS: + return "regs"; + case ORC_TYPE_REGS_PARTIAL: + return "regs (partial)"; + default: + return "?"; + } +} + +static void print_reg(unsigned int reg, int offset) +{ + if (reg == ORC_REG_BP_INDIRECT) + printf("(bp%+d)", offset); + else if (reg == ORC_REG_SP_INDIRECT) + printf("(sp)%+d", offset); + else if (reg == ORC_REG_UNDEFINED) + printf("(und)"); + else + printf("%s%+d", reg_name(reg), offset); +} + +void orc_print_dump(struct elf *dummy_elf, struct orc_entry *orc, int i) +{ + printf("type:%s", orc_type_name(orc[i].type)); + + printf(" sp:"); + print_reg(orc[i].sp_reg, bswap_if_needed(dummy_elf, orc[i].sp_offset)); + + printf(" bp:"); + print_reg(orc[i].bp_reg, bswap_if_needed(dummy_elf, orc[i].bp_offset)); + + printf(" signal:%d\n", orc[i].signal); +} diff --git a/tools/objtool/arch/x86/special.c b/tools/objtool/arch/x86/special.c index 7c97b7391279..e817a3fff449 100644 --- a/tools/objtool/arch/x86/special.c +++ b/tools/objtool/arch/x86/special.c @@ -3,52 +3,43 @@ #include <objtool/special.h> #include <objtool/builtin.h> +#include <objtool/warn.h> +#include <asm/cpufeatures.h> -#define X86_FEATURE_POPCNT (4 * 32 + 23) -#define X86_FEATURE_SMAP (9 * 32 + 20) +/* cpu feature name array generated from cpufeatures.h */ +#include "cpu-feature-names.c" -void arch_handle_alternative(unsigned short feature, struct special_alt *alt) +void arch_handle_alternative(struct special_alt *alt) { - switch (feature) { - case X86_FEATURE_SMAP: - /* - * If UACCESS validation is enabled; force that alternative; - * otherwise force it the other way. - * - * What we want to avoid is having both the original and the - * alternative code flow at the same time, in that case we can - * find paths that see the STAC but take the NOP instead of - * CLAC and the other way around. - */ - if (opts.uaccess) - alt->skip_orig = true; - else - alt->skip_alt = true; - break; - case X86_FEATURE_POPCNT: - /* - * It has been requested that we don't validate the !POPCNT - * feature path which is a "very very small percentage of - * machines". - */ - alt->skip_orig = true; - break; - default: - break; - } + static struct special_alt *group, *prev; + + /* + * Recompute orig_len for nested ALTERNATIVE()s. + */ + if (group && group->orig_sec == alt->orig_sec && + group->orig_off == alt->orig_off) { + + struct special_alt *iter = group; + for (;;) { + unsigned int len = max(iter->orig_len, alt->orig_len); + iter->orig_len = alt->orig_len = len; + + if (iter == prev) + break; + + iter = list_next_entry(iter, list); + } + + } else group = alt; + + prev = alt; } bool arch_support_alt_relocation(struct special_alt *special_alt, struct instruction *insn, struct reloc *reloc) { - /* - * The x86 alternatives code adjusts the offsets only when it - * encounters a branch instruction at the very beginning of the - * replacement group. - */ - return insn->offset == special_alt->new_off && - (insn->type == INSN_CALL || is_jump(insn)); + return true; } /* @@ -89,10 +80,11 @@ bool arch_support_alt_relocation(struct special_alt *special_alt, * TODO: Once we have DWARF CFI and smarter instruction decoding logic, * ensure the same register is used in the mov and jump instructions. * - * NOTE: RETPOLINE made it harder still to decode dynamic jumps. + * NOTE: MITIGATION_RETPOLINE made it harder still to decode dynamic jumps. */ struct reloc *arch_find_switch_table(struct objtool_file *file, - struct instruction *insn) + struct instruction *insn, + unsigned long *table_size) { struct reloc *text_reloc, *rodata_reloc; struct section *table_sec; @@ -101,14 +93,14 @@ struct reloc *arch_find_switch_table(struct objtool_file *file, /* look for a relocation which references .rodata */ text_reloc = find_reloc_by_dest_range(file->elf, insn->sec, insn->offset, insn->len); - if (!text_reloc || text_reloc->sym->type != STT_SECTION || + if (!text_reloc || !is_sec_sym(text_reloc->sym) || !text_reloc->sym->sec->rodata) return NULL; - table_offset = text_reloc->addend; + table_offset = reloc_addend(text_reloc); table_sec = text_reloc->sym->sec; - if (text_reloc->type == R_X86_64_PC32) + if (reloc_type(text_reloc) == R_X86_64_PC32) table_offset += 4; /* @@ -138,8 +130,17 @@ struct reloc *arch_find_switch_table(struct objtool_file *file, * indicates a rare GCC quirk/bug which can leave dead * code behind. */ - if (text_reloc->type == R_X86_64_PC32) + if (!file->ignore_unreachables && reloc_type(text_reloc) == R_X86_64_PC32) { + WARN_INSN(insn, "ignoring unreachables due to jump table quirk"); file->ignore_unreachables = true; + } + *table_size = 0; return rodata_reloc; } + +const char *arch_cpu_feature_name(int feature_number) +{ + return (feature_number < ARRAY_SIZE(cpu_feature_names)) ? + cpu_feature_names[feature_number] : NULL; +} |