6 files changed, 65 insertions, 19 deletions

diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index 4d6d7fc13255..c10ef78df050 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -531,6 +531,11 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
 		}
 		break;
 
+	case 0xcc:
+		/* int3 */
+		*type = INSN_TRAP;
+		break;
+
 	case 0xe3:
 		/* jecxz/jrcxz */
 		*type = INSN_JUMP_CONDITIONAL;
@@ -697,10 +702,10 @@ const char *arch_ret_insn(int len)
 {
 	static const char ret[5][5] = {
 		{ BYTE_RET },
-		{ BYTE_RET, BYTES_NOP1 },
-		{ BYTE_RET, BYTES_NOP2 },
-		{ BYTE_RET, BYTES_NOP3 },
-		{ BYTE_RET, BYTES_NOP4 },
+		{ BYTE_RET, 0xcc },
+		{ BYTE_RET, 0xcc, BYTES_NOP1 },
+		{ BYTE_RET, 0xcc, BYTES_NOP2 },
+		{ BYTE_RET, 0xcc, BYTES_NOP3 },
 	};
 
 	if (len < 1 || len > 5) {
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index 8b38b5d6fec7..38070f26105b 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -20,7 +20,7 @@
 #include <objtool/objtool.h>
 
 bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats,
-     validate_dup, vmlinux, mcount, noinstr, backup;
+     validate_dup, vmlinux, mcount, noinstr, backup, sls;
 
 static const char * const check_usage[] = {
 	"objtool check [<options>] file.o",
@@ -45,6 +45,7 @@ const struct option check_options[] = {
 	OPT_BOOLEAN('l', "vmlinux", &vmlinux, "vmlinux.o validation"),
 	OPT_BOOLEAN('M', "mcount", &mcount, "generate __mcount_loc"),
 	OPT_BOOLEAN('B', "backup", &backup, "create .orig files before modification"),
+	OPT_BOOLEAN('S', "sls", &sls, "validate straight-line-speculation"),
 	OPT_END(),
 };
 
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 21735829b860..8c1931eab5f1 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -849,6 +849,10 @@ static const char *uaccess_safe_builtin[] = {
 	"__asan_report_store16_noabort",
 	/* KCSAN */
 	"__kcsan_check_access",
+	"__kcsan_mb",
+	"__kcsan_wmb",
+	"__kcsan_rmb",
+	"__kcsan_release",
 	"kcsan_found_watchpoint",
 	"kcsan_setup_watchpoint",
 	"kcsan_check_scoped_accesses",
@@ -1068,11 +1072,11 @@ static void annotate_call_site(struct objtool_file *file,
 	}
 
 	/*
-	 * Many compilers cannot disable KCOV with a function attribute
-	 * so they need a little help, NOP out any KCOV calls from noinstr
-	 * text.
+	 * Many compilers cannot disable KCOV or sanitizer calls with a function
+	 * attribute so they need a little help, NOP out any such calls from
+	 * noinstr text.
 	 */
-	if (insn->sec->noinstr && sym->kcov) {
+	if (insn->sec->noinstr && sym->profiling_func) {
 		if (reloc) {
 			reloc->type = R_NONE;
 			elf_write_reloc(file->elf, reloc);
@@ -1987,6 +1991,31 @@ static int read_intra_function_calls(struct objtool_file *file)
 	return 0;
 }
 
+/*
+ * Return true if name matches an instrumentation function, where calls to that
+ * function from noinstr code can safely be removed, but compilers won't do so.
+ */
+static bool is_profiling_func(const char *name)
+{
+	/*
+	 * Many compilers cannot disable KCOV with a function attribute.
+	 */
+	if (!strncmp(name, "__sanitizer_cov_", 16))
+		return true;
+
+	/*
+	 * Some compilers currently do not remove __tsan_func_entry/exit nor
+	 * __tsan_atomic_signal_fence (used for barrier instrumentation) with
+	 * the __no_sanitize_thread attribute, remove them. Once the kernel's
+	 * minimum Clang version is 14.0, this can be removed.
+	 */
+	if (!strncmp(name, "__tsan_func_", 12) ||
+	    !strcmp(name, "__tsan_atomic_signal_fence"))
+		return true;
+
+	return false;
+}
+
 static int classify_symbols(struct objtool_file *file)
 {
 	struct section *sec;
@@ -2007,8 +2036,8 @@ static int classify_symbols(struct objtool_file *file)
 			if (!strcmp(func->name, "__fentry__"))
 				func->fentry = true;
 
-			if (!strncmp(func->name, "__sanitizer_cov_", 16))
-				func->kcov = true;
+			if (is_profiling_func(func->name))
+				func->profiling_func = true;
 		}
 	}
 
@@ -3084,6 +3113,12 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
 		switch (insn->type) {
 
 		case INSN_RETURN:
+			if (next_insn && next_insn->type == INSN_TRAP) {
+				next_insn->ignore = true;
+			} else if (sls && !insn->retpoline_safe) {
+				WARN_FUNC("missing int3 after ret",
+					  insn->sec, insn->offset);
+			}
 			return validate_return(func, insn, &state);
 
 		case INSN_CALL:
@@ -3127,6 +3162,14 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
 			break;
 
 		case INSN_JUMP_DYNAMIC:
+			if (next_insn && next_insn->type == INSN_TRAP) {
+				next_insn->ignore = true;
+			} else if (sls && !insn->retpoline_safe) {
+				WARN_FUNC("missing int3 after indirect jump",
+					  insn->sec, insn->offset);
+			}
+
+			/* fallthrough */
 		case INSN_JUMP_DYNAMIC_CONDITIONAL:
 			if (is_sibling_call(insn)) {
 				ret = validate_sibling_call(file, insn, &state);
@@ -3296,14 +3339,10 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
 		return true;
 
 	/*
-	 * Ignore any unused exceptions.  This can happen when a whitelisted
-	 * function has an exception table entry.
-	 *
-	 * Also ignore alternative replacement instructions.  This can happen
+	 * Ignore alternative replacement instructions.  This can happen
 	 * when a whitelisted function uses one of the ALTERNATIVE macros.
 	 */
-	if (!strcmp(insn->sec->name, ".fixup") ||
-	    !strcmp(insn->sec->name, ".altinstr_replacement") ||
+	if (!strcmp(insn->sec->name, ".altinstr_replacement") ||
 	    !strcmp(insn->sec->name, ".altinstr_aux"))
 		return true;
 
diff --git a/tools/objtool/include/objtool/arch.h b/tools/objtool/include/objtool/arch.h
index 589ff58426ab..76bae3078286 100644
--- a/tools/objtool/include/objtool/arch.h
+++ b/tools/objtool/include/objtool/arch.h
@@ -26,6 +26,7 @@ enum insn_type {
 	INSN_CLAC,
 	INSN_STD,
 	INSN_CLD,
+	INSN_TRAP,
 	INSN_OTHER,
 };
 
diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h
index 15ac0b7d3d6a..89ba869ed08f 100644
--- a/tools/objtool/include/objtool/builtin.h
+++ b/tools/objtool/include/objtool/builtin.h
@@ -9,7 +9,7 @@
 
 extern const struct option check_options[];
 extern bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats,
-            validate_dup, vmlinux, mcount, noinstr, backup;
+            validate_dup, vmlinux, mcount, noinstr, backup, sls;
 
 extern int cmd_parse_options(int argc, const char **argv, const char * const usage[]);
 
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index cdc739fa9a6f..d22336781401 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -58,7 +58,7 @@ struct symbol {
 	u8 static_call_tramp : 1;
 	u8 retpoline_thunk   : 1;
 	u8 fentry            : 1;
-	u8 kcov              : 1;
+	u8 profiling_func    : 1;
 	struct list_head pv_target;
 };