4 files changed, 175 insertions, 64 deletions

diff --git a/tools/objtool/arch/x86/Build b/tools/objtool/arch/x86/Build
index 3dedb2fd8f3a..febee0b8ee0b 100644
--- a/tools/objtool/arch/x86/Build
+++ b/tools/objtool/arch/x86/Build
@@ -1,5 +1,5 @@
-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
@@ -12,3 +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 fe1362c34564..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)
 {
-	return addend + 4;
+	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)
+{
+	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)
@@ -173,7 +237,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
 	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;
 	}
 
@@ -321,7 +385,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
 			break;
 
 		default:
-			/* WARN ? */
+			/* ERROR ? */
 			break;
 		}
 
@@ -494,6 +558,12 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
 		break;
 
 	case 0x90:
+		if (rex_b) /* XCHG %r8, %rax */
+			break;
+
+		if (prefix == 0xf3) /* REP NOP := PAUSE */
+			break;
+
 		insn->type = INSN_NOP;
 		break;
 
@@ -522,7 +592,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
 			case INAT_PFX_REPNE:
 				if (modrm == 0xca)
 					/* eretu/erets */
-					insn->type = INSN_CONTEXT_SWITCH;
+					insn->type = INSN_SYSRET;
 				break;
 			default:
 				if (modrm == 0xca)
@@ -535,21 +605,26 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
 
 			insn->type = INSN_JUMP_CONDITIONAL;
 
-		} else if (op2 == 0x05 || op2 == 0x07 || op2 == 0x34 ||
-			   op2 == 0x35) {
+		} else if (op2 == 0x05 || op2 == 0x34) {
+
+			/* syscall, sysenter */
+			insn->type = INSN_SYSCALL;
 
-			/* sysenter, sysret */
-			insn->type = INSN_CONTEXT_SWITCH;
+		} else if (op2 == 0x07 || op2 == 0x35) {
+
+			/* sysret, sysexit */
+			insn->type = INSN_SYSRET;
 
 		} else if (op2 == 0x0b || op2 == 0xb9) {
 
-			/* ud2 */
+			/* ud2, ud1 */
 			insn->type = INSN_BUG;
 
-		} else if (op2 == 0x0d || op2 == 0x1f) {
+		} else if (op2 == 0x1f) {
 
-			/* nopl/nopw */
-			insn->type = INSN_NOP;
+			/* 0f 1f /0 := NOPL */
+			if (modrm_reg == 0)
+				insn->type = INSN_NOP;
 
 		} else if (op2 == 0x1e) {
 
@@ -561,8 +636,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
 			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) {
@@ -646,7 +720,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
 			if (disp->sym->type == STT_SECTION)
 				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;
 			}
 
@@ -677,7 +751,11 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
 
 	case 0xca: /* retf */
 	case 0xcb: /* retf */
-		insn->type = INSN_CONTEXT_SWITCH;
+		insn->type = INSN_SYSRET;
+		break;
+
+	case 0xd6: /* udb */
+		insn->type = INSN_BUG;
 		break;
 
 	case 0xe0: /* loopne */
@@ -722,7 +800,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
 		} else if (modrm_reg == 5) {
 
 			/* jmpf */
-			insn->type = INSN_CONTEXT_SWITCH;
+			insn->type = INSN_SYSRET;
 
 		} else if (modrm_reg == 6) {
 
@@ -776,7 +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;
 	}
 
@@ -796,7 +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;
 	}
 
@@ -839,16 +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/orc.c b/tools/objtool/arch/x86/orc.c
index b6cd943e87f9..735e150ca6b7 100644
--- a/tools/objtool/arch/x86/orc.c
+++ b/tools/objtool/arch/x86/orc.c
@@ -5,7 +5,6 @@
 #include <objtool/check.h>
 #include <objtool/orc.h>
 #include <objtool/warn.h>
-#include <objtool/endianness.h>
 
 int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruction *insn)
 {
@@ -40,7 +39,7 @@ int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruct
 		orc->type = ORC_TYPE_REGS_PARTIAL;
 		break;
 	default:
-		WARN_INSN(insn, "unknown unwind hint type %d", cfi->type);
+		ERROR_INSN(insn, "unknown unwind hint type %d", cfi->type);
 		return -1;
 	}
 
@@ -72,7 +71,7 @@ int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruct
 		orc->sp_reg = ORC_REG_DX;
 		break;
 	default:
-		WARN_INSN(insn, "unknown CFA base reg %d", cfi->cfa.base);
+		ERROR_INSN(insn, "unknown CFA base reg %d", cfi->cfa.base);
 		return -1;
 	}
 
@@ -87,7 +86,7 @@ int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruct
 		orc->bp_reg = ORC_REG_BP;
 		break;
 	default:
-		WARN_INSN(insn, "unknown BP base reg %d", bp->base);
+		ERROR_INSN(insn, "unknown BP base reg %d", bp->base);
 		return -1;
 	}
 
diff --git a/tools/objtool/arch/x86/special.c b/tools/objtool/arch/x86/special.c
index 4ea0f9815fda..e817a3fff449 100644
--- a/tools/objtool/arch/x86/special.c
+++ b/tools/objtool/arch/x86/special.c
@@ -3,11 +3,13 @@
 
 #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)
 {
 	static struct special_alt *group, *prev;
 
@@ -31,34 +33,6 @@ void arch_handle_alternative(unsigned short feature, struct special_alt *alt)
 	} else group = alt;
 
 	prev = 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,
@@ -109,7 +83,8 @@ bool arch_support_alt_relocation(struct special_alt *special_alt,
  *    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;
@@ -118,7 +93,7 @@ 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;
 
@@ -155,8 +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 (reloc_type(text_reloc) == 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;
+}