Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

7 files changed, 1025 insertions, 0 deletions

diff --git a/tools/objtool/arch/x86/Build b/tools/objtool/arch/x86/Build
new file mode 100644
index 000000000..9f7869b5c
--- /dev/null
+++ b/tools/objtool/arch/x86/Build
@@ -0,0 +1,13 @@
+objtool-y += special.o
+objtool-y += decode.o
+
+inat_tables_script = ../arch/x86/tools/gen-insn-attr-x86.awk
+inat_tables_maps = ../arch/x86/lib/x86-opcode-map.txt
+
+$(OUTPUT)arch/x86/lib/inat-tables.c: $(inat_tables_script) $(inat_tables_maps)
+	$(call rule_mkdir)
+	$(Q)$(call echo-cmd,gen)$(AWK) -f $(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
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
new file mode 100644
index 000000000..1ed49ab4e
--- /dev/null
+++ b/tools/objtool/arch/x86/decode.c
@@ -0,0 +1,806 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#define unlikely(cond) (cond)
+#include <asm/insn.h>
+#include "../../../arch/x86/lib/inat.c"
+#include "../../../arch/x86/lib/insn.c"
+
+#define CONFIG_64BIT 1
+#include <asm/nops.h>
+
+#include <asm/orc_types.h>
+#include <objtool/check.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>
+
+static int is_x86_64(const struct elf *elf)
+{
+	switch (elf->ehdr.e_machine) {
+	case EM_X86_64:
+		return 1;
+	case EM_386:
+		return 0;
+	default:
+		WARN("unexpected ELF machine type %d", elf->ehdr.e_machine);
+		return -1;
+	}
+}
+
+bool arch_callee_saved_reg(unsigned char reg)
+{
+	switch (reg) {
+	case CFI_BP:
+	case CFI_BX:
+	case CFI_R12:
+	case CFI_R13:
+	case CFI_R14:
+	case CFI_R15:
+		return true;
+
+	case CFI_AX:
+	case CFI_CX:
+	case CFI_DX:
+	case CFI_SI:
+	case CFI_DI:
+	case CFI_SP:
+	case CFI_R8:
+	case CFI_R9:
+	case CFI_R10:
+	case CFI_R11:
+	case CFI_RA:
+	default:
+		return false;
+	}
+}
+
+unsigned long arch_dest_reloc_offset(int addend)
+{
+	return addend + 4;
+}
+
+unsigned long arch_jump_destination(struct instruction *insn)
+{
+	return insn->offset + insn->len + insn->immediate;
+}
+
+#define ADD_OP(op) \
+	if (!(op = calloc(1, sizeof(*op)))) \
+		return -1; \
+	else for (list_add_tail(&op->list, ops_list); op; op = NULL)
+
+/*
+ * Helpers to decode ModRM/SIB:
+ *
+ * r/m| AX  CX  DX  BX |  SP |  BP |  SI  DI |
+ *    | R8  R9 R10 R11 | R12 | R13 | R14 R15 |
+ * Mod+----------------+-----+-----+---------+
+ * 00 |    [r/m]       |[SIB]|[IP+]|  [r/m]  |
+ * 01 |  [r/m + d8]    |[S+d]|   [r/m + d8]  |
+ * 10 |  [r/m + d32]   |[S+D]|   [r/m + d32] |
+ * 11 |                   r/ m               |
+ */
+
+#define mod_is_mem()	(modrm_mod != 3)
+#define mod_is_reg()	(modrm_mod == 3)
+
+#define is_RIP()   ((modrm_rm & 7) == CFI_BP && modrm_mod == 0)
+#define have_SIB() ((modrm_rm & 7) == CFI_SP && mod_is_mem())
+
+#define rm_is(reg) (have_SIB() ? \
+		    sib_base == (reg) && sib_index == CFI_SP : \
+		    modrm_rm == (reg))
+
+#define rm_is_mem(reg)	(mod_is_mem() && !is_RIP() && rm_is(reg))
+#define rm_is_reg(reg)	(mod_is_reg() && modrm_rm == (reg))
+
+static bool has_notrack_prefix(struct insn *insn)
+{
+	int i;
+
+	for (i = 0; i < insn->prefixes.nbytes; i++) {
+		if (insn->prefixes.bytes[i] == 0x3e)
+			return true;
+	}
+
+	return false;
+}
+
+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)
+{
+	const struct elf *elf = file->elf;
+	struct insn insn;
+	int x86_64, ret;
+	unsigned char op1, op2, op3, prefix,
+		      rex = 0, rex_b = 0, rex_r = 0, rex_w = 0, rex_x = 0,
+		      modrm = 0, modrm_mod = 0, modrm_rm = 0, modrm_reg = 0,
+		      sib = 0, /* sib_scale = 0, */ sib_index = 0, sib_base = 0;
+	struct stack_op *op = NULL;
+	struct symbol *sym;
+	u64 imm;
+
+	x86_64 = is_x86_64(elf);
+	if (x86_64 == -1)
+		return -1;
+
+	ret = insn_decode(&insn, 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);
+		return -1;
+	}
+
+	*len = insn.length;
+	*type = INSN_OTHER;
+
+	if (insn.vex_prefix.nbytes)
+		return 0;
+
+	prefix = insn.prefixes.bytes[0];
+
+	op1 = insn.opcode.bytes[0];
+	op2 = insn.opcode.bytes[1];
+	op3 = insn.opcode.bytes[2];
+
+	if (insn.rex_prefix.nbytes) {
+		rex = insn.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];
+		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];
+		/* sib_scale = X86_SIB_SCALE(sib); */
+		sib_index = X86_SIB_INDEX(sib) + 8*rex_x;
+		sib_base  = X86_SIB_BASE(sib)  + 8*rex_b;
+	}
+
+	switch (op1) {
+
+	case 0x1:
+	case 0x29:
+		if (rex_w && rm_is_reg(CFI_SP)) {
+
+			/* add/sub reg, %rsp */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_ADD;
+				op->src.reg = modrm_reg;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = CFI_SP;
+			}
+		}
+		break;
+
+	case 0x50 ... 0x57:
+
+		/* push reg */
+		ADD_OP(op) {
+			op->src.type = OP_SRC_REG;
+			op->src.reg = (op1 & 0x7) + 8*rex_b;
+			op->dest.type = OP_DEST_PUSH;
+		}
+
+		break;
+
+	case 0x58 ... 0x5f:
+
+		/* pop reg */
+		ADD_OP(op) {
+			op->src.type = OP_SRC_POP;
+			op->dest.type = OP_DEST_REG;
+			op->dest.reg = (op1 & 0x7) + 8*rex_b;
+		}
+
+		break;
+
+	case 0x68:
+	case 0x6a:
+		/* push immediate */
+		ADD_OP(op) {
+			op->src.type = OP_SRC_CONST;
+			op->dest.type = OP_DEST_PUSH;
+		}
+		break;
+
+	case 0x70 ... 0x7f:
+		*type = INSN_JUMP_CONDITIONAL;
+		break;
+
+	case 0x80 ... 0x83:
+		/*
+		 * 1000 00sw : mod OP r/m : immediate
+		 *
+		 * s - sign extend immediate
+		 * w - imm8 / imm32
+		 *
+		 * OP: 000 ADD    100 AND
+		 *     001 OR     101 SUB
+		 *     010 ADC    110 XOR
+		 *     011 SBB    111 CMP
+		 */
+
+		/* 64bit only */
+		if (!rex_w)
+			break;
+
+		/* %rsp target only */
+		if (!rm_is_reg(CFI_SP))
+			break;
+
+		imm = insn.immediate.value;
+		if (op1 & 2) { /* sign extend */
+			if (op1 & 1) { /* imm32 */
+				imm <<= 32;
+				imm = (s64)imm >> 32;
+			} else { /* imm8 */
+				imm <<= 56;
+				imm = (s64)imm >> 56;
+			}
+		}
+
+		switch (modrm_reg & 7) {
+		case 5:
+			imm = -imm;
+			/* fallthrough */
+		case 0:
+			/* add/sub imm, %rsp */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_ADD;
+				op->src.reg = CFI_SP;
+				op->src.offset = imm;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = CFI_SP;
+			}
+			break;
+
+		case 4:
+			/* and imm, %rsp */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_AND;
+				op->src.reg = CFI_SP;
+				op->src.offset = insn.immediate.value;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = CFI_SP;
+			}
+			break;
+
+		default:
+			/* WARN ? */
+			break;
+		}
+
+		break;
+
+	case 0x89:
+		if (!rex_w)
+			break;
+
+		if (modrm_reg == CFI_SP) {
+
+			if (mod_is_reg()) {
+				/* mov %rsp, reg */
+				ADD_OP(op) {
+					op->src.type = OP_SRC_REG;
+					op->src.reg = CFI_SP;
+					op->dest.type = OP_DEST_REG;
+					op->dest.reg = modrm_rm;
+				}
+				break;
+
+			} else {
+				/* skip RIP relative displacement */
+				if (is_RIP())
+					break;
+
+				/* skip nontrivial SIB */
+				if (have_SIB()) {
+					modrm_rm = sib_base;
+					if (sib_index != CFI_SP)
+						break;
+				}
+
+				/* mov %rsp, disp(%reg) */
+				ADD_OP(op) {
+					op->src.type = OP_SRC_REG;
+					op->src.reg = CFI_SP;
+					op->dest.type = OP_DEST_REG_INDIRECT;
+					op->dest.reg = modrm_rm;
+					op->dest.offset = insn.displacement.value;
+				}
+				break;
+			}
+
+			break;
+		}
+
+		if (rm_is_reg(CFI_SP)) {
+
+			/* mov reg, %rsp */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG;
+				op->src.reg = modrm_reg;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = CFI_SP;
+			}
+			break;
+		}
+
+		/* fallthrough */
+	case 0x88:
+		if (!rex_w)
+			break;
+
+		if (rm_is_mem(CFI_BP)) {
+
+			/* mov reg, disp(%rbp) */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG;
+				op->src.reg = modrm_reg;
+				op->dest.type = OP_DEST_REG_INDIRECT;
+				op->dest.reg = CFI_BP;
+				op->dest.offset = insn.displacement.value;
+			}
+			break;
+		}
+
+		if (rm_is_mem(CFI_SP)) {
+
+			/* mov reg, disp(%rsp) */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG;
+				op->src.reg = modrm_reg;
+				op->dest.type = OP_DEST_REG_INDIRECT;
+				op->dest.reg = CFI_SP;
+				op->dest.offset = insn.displacement.value;
+			}
+			break;
+		}
+
+		break;
+
+	case 0x8b:
+		if (!rex_w)
+			break;
+
+		if (rm_is_mem(CFI_BP)) {
+
+			/* mov disp(%rbp), reg */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG_INDIRECT;
+				op->src.reg = CFI_BP;
+				op->src.offset = insn.displacement.value;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = modrm_reg;
+			}
+			break;
+		}
+
+		if (rm_is_mem(CFI_SP)) {
+
+			/* mov disp(%rsp), reg */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG_INDIRECT;
+				op->src.reg = CFI_SP;
+				op->src.offset = insn.displacement.value;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = modrm_reg;
+			}
+			break;
+		}
+
+		break;
+
+	case 0x8d:
+		if (mod_is_reg()) {
+			WARN("invalid LEA encoding at %s:0x%lx", sec->name, offset);
+			break;
+		}
+
+		/* skip non 64bit ops */
+		if (!rex_w)
+			break;
+
+		/* skip RIP relative displacement */
+		if (is_RIP())
+			break;
+
+		/* skip nontrivial SIB */
+		if (have_SIB()) {
+			modrm_rm = sib_base;
+			if (sib_index != CFI_SP)
+				break;
+		}
+
+		/* lea disp(%src), %dst */
+		ADD_OP(op) {
+			op->src.offset = insn.displacement.value;
+			if (!op->src.offset) {
+				/* lea (%src), %dst */
+				op->src.type = OP_SRC_REG;
+			} else {
+				/* lea disp(%src), %dst */
+				op->src.type = OP_SRC_ADD;
+			}
+			op->src.reg = modrm_rm;
+			op->dest.type = OP_DEST_REG;
+			op->dest.reg = modrm_reg;
+		}
+		break;
+
+	case 0x8f:
+		/* pop to mem */
+		ADD_OP(op) {
+			op->src.type = OP_SRC_POP;
+			op->dest.type = OP_DEST_MEM;
+		}
+		break;
+
+	case 0x90:
+		*type = INSN_NOP;
+		break;
+
+	case 0x9c:
+		/* pushf */
+		ADD_OP(op) {
+			op->src.type = OP_SRC_CONST;
+			op->dest.type = OP_DEST_PUSHF;
+		}
+		break;
+
+	case 0x9d:
+		/* popf */
+		ADD_OP(op) {
+			op->src.type = OP_SRC_POPF;
+			op->dest.type = OP_DEST_MEM;
+		}
+		break;
+
+	case 0x0f:
+
+		if (op2 == 0x01) {
+
+			if (modrm == 0xca)
+				*type = INSN_CLAC;
+			else if (modrm == 0xcb)
+				*type = INSN_STAC;
+
+		} else if (op2 >= 0x80 && op2 <= 0x8f) {
+
+			*type = INSN_JUMP_CONDITIONAL;
+
+		} else if (op2 == 0x05 || op2 == 0x07 || op2 == 0x34 ||
+			   op2 == 0x35) {
+
+			/* sysenter, sysret */
+			*type = INSN_CONTEXT_SWITCH;
+
+		} else if (op2 == 0x0b || op2 == 0xb9) {
+
+			/* ud2 */
+			*type = INSN_BUG;
+
+		} else if (op2 == 0x0d || op2 == 0x1f) {
+
+			/* nopl/nopw */
+			*type = INSN_NOP;
+
+		} else if (op2 == 0x1e) {
+
+			if (prefix == 0xf3 && (modrm == 0xfa || modrm == 0xfb))
+				*type = INSN_ENDBR;
+
+
+		} else if (op2 == 0x38 && op3 == 0xf8) {
+			if (insn.prefixes.nbytes == 1 &&
+			    insn.prefixes.bytes[0] == 0xf2) {
+				/* ENQCMD cannot be used in the kernel. */
+				WARN("ENQCMD instruction at %s:%lx", sec->name,
+				     offset);
+			}
+
+		} else if (op2 == 0xa0 || op2 == 0xa8) {
+
+			/* push fs/gs */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_CONST;
+				op->dest.type = OP_DEST_PUSH;
+			}
+
+		} else if (op2 == 0xa1 || op2 == 0xa9) {
+
+			/* pop fs/gs */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_POP;
+				op->dest.type = OP_DEST_MEM;
+			}
+		}
+
+		break;
+
+	case 0xc9:
+		/*
+		 * leave
+		 *
+		 * equivalent to:
+		 * mov bp, sp
+		 * pop bp
+		 */
+		ADD_OP(op) {
+			op->src.type = OP_SRC_REG;
+			op->src.reg = CFI_BP;
+			op->dest.type = OP_DEST_REG;
+			op->dest.reg = CFI_SP;
+		}
+		ADD_OP(op) {
+			op->src.type = OP_SRC_POP;
+			op->dest.type = OP_DEST_REG;
+			op->dest.reg = CFI_BP;
+		}
+		break;
+
+	case 0xcc:
+		/* int3 */
+		*type = INSN_TRAP;
+		break;
+
+	case 0xe3:
+		/* jecxz/jrcxz */
+		*type = INSN_JUMP_CONDITIONAL;
+		break;
+
+	case 0xe9:
+	case 0xeb:
+		*type = INSN_JUMP_UNCONDITIONAL;
+		break;
+
+	case 0xc2:
+	case 0xc3:
+		*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)) {
+			struct reloc *immr, *disp;
+			struct symbol *func;
+			int idx;
+
+			immr = find_reloc_by_dest(elf, (void *)sec, offset+3);
+			disp = find_reloc_by_dest(elf, (void *)sec, offset+7);
+
+			if (!immr || strcmp(immr->sym->name, "pv_ops"))
+				break;
+
+			idx = (immr->addend + 8) / sizeof(void *);
+
+			func = disp->sym;
+			if (disp->sym->type == STT_SECTION)
+				func = find_symbol_by_offset(disp->sym->sec, disp->addend);
+			if (!func) {
+				WARN("no func for pv_ops[]");
+				return -1;
+			}
+
+			objtool_pv_add(file, idx, func);
+		}
+
+		break;
+
+	case 0xcf: /* iret */
+		/*
+		 * Handle sync_core(), which has an IRET to self.
+		 * All other IRET are in STT_NONE entry code.
+		 */
+		sym = find_symbol_containing(sec, offset);
+		if (sym && sym->type == STT_FUNC) {
+			ADD_OP(op) {
+				/* add $40, %rsp */
+				op->src.type = OP_SRC_ADD;
+				op->src.reg = CFI_SP;
+				op->src.offset = 5*8;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = CFI_SP;
+			}
+			break;
+		}
+
+		/* fallthrough */
+
+	case 0xca: /* retf */
+	case 0xcb: /* retf */
+		*type = INSN_CONTEXT_SWITCH;
+		break;
+
+	case 0xe0: /* loopne */
+	case 0xe1: /* loope */
+	case 0xe2: /* loop */
+		*type = INSN_JUMP_CONDITIONAL;
+		break;
+
+	case 0xe8:
+		*type = INSN_CALL;
+		/*
+		 * For the impact on the stack, a CALL behaves like
+		 * a PUSH of an immediate value (the return address).
+		 */
+		ADD_OP(op) {
+			op->src.type = OP_SRC_CONST;
+			op->dest.type = OP_DEST_PUSH;
+		}
+		break;
+
+	case 0xfc:
+		*type = INSN_CLD;
+		break;
+
+	case 0xfd:
+		*type = INSN_STD;
+		break;
+
+	case 0xff:
+		if (modrm_reg == 2 || modrm_reg == 3) {
+
+			*type = INSN_CALL_DYNAMIC;
+			if (has_notrack_prefix(&insn))
+				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))
+				WARN("notrack prefix found at %s:0x%lx", sec->name, offset);
+
+		} else if (modrm_reg == 5) {
+
+			/* jmpf */
+			*type = INSN_CONTEXT_SWITCH;
+
+		} else if (modrm_reg == 6) {
+
+			/* push from mem */
+			ADD_OP(op) {
+				op->src.type = OP_SRC_CONST;
+				op->dest.type = OP_DEST_PUSH;
+			}
+		}
+
+		break;
+
+	default:
+		break;
+	}
+
+	*immediate = insn.immediate.nbytes ? insn.immediate.value : 0;
+
+	return 0;
+}
+
+void arch_initial_func_cfi_state(struct cfi_init_state *state)
+{
+	int i;
+
+	for (i = 0; i < CFI_NUM_REGS; i++) {
+		state->regs[i].base = CFI_UNDEFINED;
+		state->regs[i].offset = 0;
+	}
+
+	/* initial CFA (call frame address) */
+	state->cfa.base = CFI_SP;
+	state->cfa.offset = 8;
+
+	/* initial RA (return address) */
+	state->regs[CFI_RA].base = CFI_CFA;
+	state->regs[CFI_RA].offset = -8;
+}
+
+const char *arch_nop_insn(int len)
+{
+	static const char nops[5][5] = {
+		{ BYTES_NOP1 },
+		{ BYTES_NOP2 },
+		{ BYTES_NOP3 },
+		{ BYTES_NOP4 },
+		{ BYTES_NOP5 },
+	};
+
+	if (len < 1 || len > 5) {
+		WARN("invalid NOP size: %d\n", len);
+		return NULL;
+	}
+
+	return nops[len-1];
+}
+
+#define BYTE_RET	0xC3
+
+const char *arch_ret_insn(int len)
+{
+	static const char ret[5][5] = {
+		{ BYTE_RET },
+		{ BYTE_RET, 0xcc },
+		{ BYTE_RET, 0xcc, BYTES_NOP1 },
+		{ BYTE_RET, 0xcc, BYTES_NOP2 },
+		{ BYTE_RET, 0xcc, BYTES_NOP3 },
+	};
+
+	if (len < 1 || len > 5) {
+		WARN("invalid RET size: %d\n", len);
+		return NULL;
+	}
+
+	return ret[len-1];
+}
+
+int arch_decode_hint_reg(u8 sp_reg, int *base)
+{
+	switch (sp_reg) {
+	case ORC_REG_UNDEFINED:
+		*base = CFI_UNDEFINED;
+		break;
+	case ORC_REG_SP:
+		*base = CFI_SP;
+		break;
+	case ORC_REG_BP:
+		*base = CFI_BP;
+		break;
+	case ORC_REG_SP_INDIRECT:
+		*base = CFI_SP_INDIRECT;
+		break;
+	case ORC_REG_R10:
+		*base = CFI_R10;
+		break;
+	case ORC_REG_R13:
+		*base = CFI_R13;
+		break;
+	case ORC_REG_DI:
+		*base = CFI_DI;
+		break;
+	case ORC_REG_DX:
+		*base = CFI_DX;
+		break;
+	default:
+		return -1;
+	}
+
+	return 0;
+}
+
+bool arch_is_retpoline(struct symbol *sym)
+{
+	return !strncmp(sym->name, "__x86_indirect_", 15);
+}
+
+bool arch_is_rethunk(struct symbol *sym)
+{
+	return !strcmp(sym->name, "__x86_return_thunk");
+}
+
+bool arch_is_embedded_insn(struct symbol *sym)
+{
+	return !strcmp(sym->name, "retbleed_return_thunk") ||
+	       !strcmp(sym->name, "srso_safe_ret");
+}
diff --git a/tools/objtool/arch/x86/include/arch/cfi_regs.h b/tools/objtool/arch/x86/include/arch/cfi_regs.h
new file mode 100644
index 000000000..0579d22c4
--- /dev/null
+++ b/tools/objtool/arch/x86/include/arch/cfi_regs.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef _OBJTOOL_CFI_REGS_H
+#define _OBJTOOL_CFI_REGS_H
+
+#define CFI_AX			0
+#define CFI_CX			1
+#define CFI_DX			2
+#define CFI_BX			3
+#define CFI_SP			4
+#define CFI_BP			5
+#define CFI_SI			6
+#define CFI_DI			7
+#define CFI_R8			8
+#define CFI_R9			9
+#define CFI_R10			10
+#define CFI_R11			11
+#define CFI_R12			12
+#define CFI_R13			13
+#define CFI_R14			14
+#define CFI_R15			15
+#define CFI_RA			16
+#define CFI_NUM_REGS		17
+
+#endif /* _OBJTOOL_CFI_REGS_H */
diff --git a/tools/objtool/arch/x86/include/arch/elf.h b/tools/objtool/arch/x86/include/arch/elf.h
new file mode 100644
index 000000000..69cc4264b
--- /dev/null
+++ b/tools/objtool/arch/x86/include/arch/elf.h
@@ -0,0 +1,6 @@
+#ifndef _OBJTOOL_ARCH_ELF
+#define _OBJTOOL_ARCH_ELF
+
+#define R_NONE R_X86_64_NONE
+
+#endif /* _OBJTOOL_ARCH_ELF */
diff --git a/tools/objtool/arch/x86/include/arch/endianness.h b/tools/objtool/arch/x86/include/arch/endianness.h
new file mode 100644
index 000000000..7c362527d
--- /dev/null
+++ b/tools/objtool/arch/x86/include/arch/endianness.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _ARCH_ENDIANNESS_H
+#define _ARCH_ENDIANNESS_H
+
+#include <endian.h>
+
+#define __TARGET_BYTE_ORDER __LITTLE_ENDIAN
+
+#endif /* _ARCH_ENDIANNESS_H */
diff --git a/tools/objtool/arch/x86/include/arch/special.h b/tools/objtool/arch/x86/include/arch/special.h
new file mode 100644
index 000000000..f2918f789
--- /dev/null
+++ b/tools/objtool/arch/x86/include/arch/special.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _X86_ARCH_SPECIAL_H
+#define _X86_ARCH_SPECIAL_H
+
+#define EX_ENTRY_SIZE		12
+#define EX_ORIG_OFFSET		0
+#define EX_NEW_OFFSET		4
+
+#define JUMP_ENTRY_SIZE		16
+#define JUMP_ORIG_OFFSET	0
+#define JUMP_NEW_OFFSET		4
+#define JUMP_KEY_OFFSET		8
+
+#define ALT_ENTRY_SIZE		12
+#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
+
+#endif /* _X86_ARCH_SPECIAL_H */
diff --git a/tools/objtool/arch/x86/special.c b/tools/objtool/arch/x86/special.c
new file mode 100644
index 000000000..7c97b7391
--- /dev/null
+++ b/tools/objtool/arch/x86/special.c
@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <string.h>
+
+#include <objtool/special.h>
+#include <objtool/builtin.h>
+
+#define X86_FEATURE_POPCNT (4 * 32 + 23)
+#define X86_FEATURE_SMAP   (9 * 32 + 20)
+
+void arch_handle_alternative(unsigned short feature, 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;
+	}
+}
+
+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));
+}
+
+/*
+ * There are 3 basic jump table patterns:
+ *
+ * 1. jmpq *[rodata addr](,%reg,8)
+ *
+ *    This is the most common case by far.  It jumps to an address in a simple
+ *    jump table which is stored in .rodata.
+ *
+ * 2. jmpq *[rodata addr](%rip)
+ *
+ *    This is caused by a rare GCC quirk, currently only seen in three driver
+ *    functions in the kernel, only with certain obscure non-distro configs.
+ *
+ *    As part of an optimization, GCC makes a copy of an existing switch jump
+ *    table, modifies it, and then hard-codes the jump (albeit with an indirect
+ *    jump) to use a single entry in the table.  The rest of the jump table and
+ *    some of its jump targets remain as dead code.
+ *
+ *    In such a case we can just crudely ignore all unreachable instruction
+ *    warnings for the entire object file.  Ideally we would just ignore them
+ *    for the function, but that would require redesigning the code quite a
+ *    bit.  And honestly that's just not worth doing: unreachable instruction
+ *    warnings are of questionable value anyway, and this is such a rare issue.
+ *
+ * 3. mov [rodata addr],%reg1
+ *    ... some instructions ...
+ *    jmpq *(%reg1,%reg2,8)
+ *
+ *    This is a fairly uncommon pattern which is new for GCC 6.  As of this
+ *    writing, there are 11 occurrences of it in the allmodconfig kernel.
+ *
+ *    As of GCC 7 there are quite a few more of these and the 'in between' code
+ *    is significant. Esp. with KASAN enabled some of the code between the mov
+ *    and jmpq uses .rodata itself, which can confuse things.
+ *
+ *    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.
+ */
+struct reloc *arch_find_switch_table(struct objtool_file *file,
+				    struct instruction *insn)
+{
+	struct reloc  *text_reloc, *rodata_reloc;
+	struct section *table_sec;
+	unsigned long table_offset;
+
+	/* 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 ||
+	    !text_reloc->sym->sec->rodata)
+		return NULL;
+
+	table_offset = text_reloc->addend;
+	table_sec = text_reloc->sym->sec;
+
+	if (text_reloc->type == R_X86_64_PC32)
+		table_offset += 4;
+
+	/*
+	 * Make sure the .rodata address isn't associated with a
+	 * symbol.  GCC jump tables are anonymous data.
+	 *
+	 * Also support C jump tables which are in the same format as
+	 * switch jump tables.  For objtool to recognize them, they
+	 * need to be placed in the C_JUMP_TABLE_SECTION section.  They
+	 * have symbols associated with them.
+	 */
+	if (find_symbol_containing(table_sec, table_offset) &&
+	    strcmp(table_sec->name, C_JUMP_TABLE_SECTION))
+		return NULL;
+
+	/*
+	 * Each table entry has a rela associated with it.  The rela
+	 * should reference text in the same function as the original
+	 * instruction.
+	 */
+	rodata_reloc = find_reloc_by_dest(file->elf, table_sec, table_offset);
+	if (!rodata_reloc)
+		return NULL;
+
+	/*
+	 * Use of RIP-relative switch jumps is quite rare, and
+	 * indicates a rare GCC quirk/bug which can leave dead
+	 * code behind.
+	 */
+	if (text_reloc->type == R_X86_64_PC32)
+		file->ignore_unreachables = true;
+
+	return rodata_reloc;
+}