From 6545eb030e6f14cef8793a86312483c788eaee46 Mon Sep 17 00:00:00 2001
From: Julien Thierry <jthierry@redhat.com>
Date: Tue, 25 Aug 2020 13:47:39 +0100
Subject: objtool: Move object file loading out of check()

Structure objtool_file can be used by different subcommands. In fact
it already is, by check and orc.

Provide a function that allows to initialize objtool_file, that builtin
can call, without relying on check to do the correct setup for them and
explicitly hand the objtool_file to them.

Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/builtin-check.c |  7 ++++++-
 tools/objtool/builtin-orc.c   |  8 +++++++-
 tools/objtool/check.c         | 42 +++++++++++++-----------------------------
 tools/objtool/objtool.c       | 30 ++++++++++++++++++++++++++++++
 tools/objtool/objtool.h       |  4 +++-
 tools/objtool/weak.c          |  4 +---
 6 files changed, 60 insertions(+), 35 deletions(-)

(limited to 'tools')

diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index 7a44174967b5..0126ec3bb6c9 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -41,6 +41,7 @@ const struct option check_options[] = {
 int cmd_check(int argc, const char **argv)
 {
 	const char *objname, *s;
+	struct objtool_file *file;
 
 	argc = parse_options(argc, argv, check_options, check_usage, 0);
 
@@ -53,5 +54,9 @@ int cmd_check(int argc, const char **argv)
 	if (s && !s[9])
 		vmlinux = true;
 
-	return check(objname, false);
+	file = objtool_open_read(objname);
+	if (!file)
+		return 1;
+
+	return check(file, false);
 }
diff --git a/tools/objtool/builtin-orc.c b/tools/objtool/builtin-orc.c
index b1dfe2007962..3979f275a775 100644
--- a/tools/objtool/builtin-orc.c
+++ b/tools/objtool/builtin-orc.c
@@ -31,13 +31,19 @@ int cmd_orc(int argc, const char **argv)
 		usage_with_options(orc_usage, check_options);
 
 	if (!strncmp(argv[0], "gen", 3)) {
+		struct objtool_file *file;
+
 		argc = parse_options(argc, argv, check_options, orc_usage, 0);
 		if (argc != 1)
 			usage_with_options(orc_usage, check_options);
 
 		objname = argv[0];
 
-		return check(objname, true);
+		file = objtool_open_read(objname);
+		if (!file)
+			return 1;
+
+		return check(file, true);
 	}
 
 	if (!strcmp(argv[0], "dump")) {
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 75d0cd2f9044..9d4efa3b12ba 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -28,7 +28,6 @@ struct alternative {
 	bool skip_orig;
 };
 
-const char *objname;
 struct cfi_init_state initial_func_cfi;
 
 struct instruction *find_insn(struct objtool_file *file,
@@ -2909,37 +2908,22 @@ static int validate_reachable_instructions(struct objtool_file *file)
 	return 0;
 }
 
-static struct objtool_file file;
-
-int check(const char *_objname, bool orc)
+int check(struct objtool_file *file, bool orc)
 {
 	int ret, warnings = 0;
 
-	objname = _objname;
-
-	file.elf = elf_open_read(objname, O_RDWR);
-	if (!file.elf)
-		return 1;
-
-	INIT_LIST_HEAD(&file.insn_list);
-	hash_init(file.insn_hash);
-	INIT_LIST_HEAD(&file.static_call_list);
-	file.c_file = !vmlinux && find_section_by_name(file.elf, ".comment");
-	file.ignore_unreachables = no_unreachable;
-	file.hints = false;
-
 	arch_initial_func_cfi_state(&initial_func_cfi);
 
-	ret = decode_sections(&file);
+	ret = decode_sections(file);
 	if (ret < 0)
 		goto out;
 	warnings += ret;
 
-	if (list_empty(&file.insn_list))
+	if (list_empty(&file->insn_list))
 		goto out;
 
 	if (vmlinux && !validate_dup) {
-		ret = validate_vmlinux_functions(&file);
+		ret = validate_vmlinux_functions(file);
 		if (ret < 0)
 			goto out;
 
@@ -2948,46 +2932,46 @@ int check(const char *_objname, bool orc)
 	}
 
 	if (retpoline) {
-		ret = validate_retpoline(&file);
+		ret = validate_retpoline(file);
 		if (ret < 0)
 			return ret;
 		warnings += ret;
 	}
 
-	ret = validate_functions(&file);
+	ret = validate_functions(file);
 	if (ret < 0)
 		goto out;
 	warnings += ret;
 
-	ret = validate_unwind_hints(&file, NULL);
+	ret = validate_unwind_hints(file, NULL);
 	if (ret < 0)
 		goto out;
 	warnings += ret;
 
 	if (!warnings) {
-		ret = validate_reachable_instructions(&file);
+		ret = validate_reachable_instructions(file);
 		if (ret < 0)
 			goto out;
 		warnings += ret;
 	}
 
-	ret = create_static_call_sections(&file);
+	ret = create_static_call_sections(file);
 	if (ret < 0)
 		goto out;
 	warnings += ret;
 
 	if (orc) {
-		ret = create_orc(&file);
+		ret = create_orc(file);
 		if (ret < 0)
 			goto out;
 
-		ret = create_orc_sections(&file);
+		ret = create_orc_sections(file);
 		if (ret < 0)
 			goto out;
 	}
 
-	if (file.elf->changed) {
-		ret = elf_write(file.elf);
+	if (file->elf->changed) {
+		ret = elf_write(file->elf);
 		if (ret < 0)
 			goto out;
 	}
diff --git a/tools/objtool/objtool.c b/tools/objtool/objtool.c
index 58fdda510653..9df0cd86d310 100644
--- a/tools/objtool/objtool.c
+++ b/tools/objtool/objtool.c
@@ -22,6 +22,8 @@
 #include <linux/kernel.h>
 
 #include "builtin.h"
+#include "objtool.h"
+#include "warn.h"
 
 struct cmd_struct {
 	const char *name;
@@ -39,6 +41,34 @@ static struct cmd_struct objtool_cmds[] = {
 
 bool help;
 
+const char *objname;
+static struct objtool_file file;
+
+struct objtool_file *objtool_open_read(const char *_objname)
+{
+	if (objname) {
+		if (strcmp(objname, _objname)) {
+			WARN("won't handle more than one file at a time");
+			return NULL;
+		}
+		return &file;
+	}
+	objname = _objname;
+
+	file.elf = elf_open_read(objname, O_RDWR);
+	if (!file.elf)
+		return NULL;
+
+	INIT_LIST_HEAD(&file.insn_list);
+	hash_init(file.insn_hash);
+	INIT_LIST_HEAD(&file.static_call_list);
+	file.c_file = !vmlinux && find_section_by_name(file.elf, ".comment");
+	file.ignore_unreachables = no_unreachable;
+	file.hints = false;
+
+	return &file;
+}
+
 static void cmd_usage(void)
 {
 	unsigned int i, longest = 0;
diff --git a/tools/objtool/objtool.h b/tools/objtool/objtool.h
index 9a7cd0b88bd8..7efc43f22174 100644
--- a/tools/objtool/objtool.h
+++ b/tools/objtool/objtool.h
@@ -20,7 +20,9 @@ struct objtool_file {
 	bool ignore_unreachables, c_file, hints, rodata;
 };
 
-int check(const char *objname, bool orc);
+struct objtool_file *objtool_open_read(const char *_objname);
+
+int check(struct objtool_file *file, bool orc);
 int orc_dump(const char *objname);
 int create_orc(struct objtool_file *file);
 int create_orc_sections(struct objtool_file *file);
diff --git a/tools/objtool/weak.c b/tools/objtool/weak.c
index 942ea5e8ac36..82698319f008 100644
--- a/tools/objtool/weak.c
+++ b/tools/objtool/weak.c
@@ -17,9 +17,7 @@
 	return ENOSYS;							\
 })
 
-const char __weak *objname;
-
-int __weak check(const char *_objname, bool orc)
+int __weak check(struct objtool_file *file, bool orc)
 {
 	UNSUPPORTED("check subcommand");
 }
-- 
cgit v1.2.3


From d44becb9decf4438d1e555b1428634964d2e5764 Mon Sep 17 00:00:00 2001
From: Julien Thierry <jthierry@redhat.com>
Date: Tue, 25 Aug 2020 13:47:40 +0100
Subject: objtool: Move ORC logic out of check()

Now that the objtool_file can be obtained outside of the check function,
orc generation builtin no longer requires check to explicitly call its
orc related functions.

Signed-off-by: Julien Thierry <jthierry@redhat.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/builtin-check.c | 10 +++++++++-
 tools/objtool/builtin-orc.c   | 21 ++++++++++++++++++++-
 tools/objtool/check.c         | 18 +-----------------
 tools/objtool/objtool.h       |  2 +-
 tools/objtool/weak.c          |  2 +-
 5 files changed, 32 insertions(+), 21 deletions(-)

(limited to 'tools')

diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index 0126ec3bb6c9..c6d199bfd0ae 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -42,6 +42,7 @@ int cmd_check(int argc, const char **argv)
 {
 	const char *objname, *s;
 	struct objtool_file *file;
+	int ret;
 
 	argc = parse_options(argc, argv, check_options, check_usage, 0);
 
@@ -58,5 +59,12 @@ int cmd_check(int argc, const char **argv)
 	if (!file)
 		return 1;
 
-	return check(file, false);
+	ret = check(file);
+	if (ret)
+		return ret;
+
+	if (file->elf->changed)
+		return elf_write(file->elf);
+
+	return 0;
 }
diff --git a/tools/objtool/builtin-orc.c b/tools/objtool/builtin-orc.c
index 3979f275a775..7b31121fa60b 100644
--- a/tools/objtool/builtin-orc.c
+++ b/tools/objtool/builtin-orc.c
@@ -32,6 +32,7 @@ int cmd_orc(int argc, const char **argv)
 
 	if (!strncmp(argv[0], "gen", 3)) {
 		struct objtool_file *file;
+		int ret;
 
 		argc = parse_options(argc, argv, check_options, orc_usage, 0);
 		if (argc != 1)
@@ -43,7 +44,25 @@ int cmd_orc(int argc, const char **argv)
 		if (!file)
 			return 1;
 
-		return check(file, true);
+		ret = check(file);
+		if (ret)
+			return ret;
+
+		if (list_empty(&file->insn_list))
+			return 0;
+
+		ret = create_orc(file);
+		if (ret)
+			return ret;
+
+		ret = create_orc_sections(file);
+		if (ret)
+			return ret;
+
+		if (!file->elf->changed)
+			return 0;
+
+		return elf_write(file->elf);
 	}
 
 	if (!strcmp(argv[0], "dump")) {
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 9d4efa3b12ba..4afc2d5465b9 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2908,7 +2908,7 @@ static int validate_reachable_instructions(struct objtool_file *file)
 	return 0;
 }
 
-int check(struct objtool_file *file, bool orc)
+int check(struct objtool_file *file)
 {
 	int ret, warnings = 0;
 
@@ -2960,22 +2960,6 @@ int check(struct objtool_file *file, bool orc)
 		goto out;
 	warnings += ret;
 
-	if (orc) {
-		ret = create_orc(file);
-		if (ret < 0)
-			goto out;
-
-		ret = create_orc_sections(file);
-		if (ret < 0)
-			goto out;
-	}
-
-	if (file->elf->changed) {
-		ret = elf_write(file->elf);
-		if (ret < 0)
-			goto out;
-	}
-
 out:
 	if (ret < 0) {
 		/*
diff --git a/tools/objtool/objtool.h b/tools/objtool/objtool.h
index 7efc43f22174..a635f68a9b09 100644
--- a/tools/objtool/objtool.h
+++ b/tools/objtool/objtool.h
@@ -22,7 +22,7 @@ struct objtool_file {
 
 struct objtool_file *objtool_open_read(const char *_objname);
 
-int check(struct objtool_file *file, bool orc);
+int check(struct objtool_file *file);
 int orc_dump(const char *objname);
 int create_orc(struct objtool_file *file);
 int create_orc_sections(struct objtool_file *file);
diff --git a/tools/objtool/weak.c b/tools/objtool/weak.c
index 82698319f008..29180d599b08 100644
--- a/tools/objtool/weak.c
+++ b/tools/objtool/weak.c
@@ -17,7 +17,7 @@
 	return ENOSYS;							\
 })
 
-int __weak check(struct objtool_file *file, bool orc)
+int __weak check(struct objtool_file *file)
 {
 	UNSUPPORTED("check subcommand");
 }
-- 
cgit v1.2.3


From 3eaecac88a17f7fdf29561a197dc728f7f697c60 Mon Sep 17 00:00:00 2001
From: Julien Thierry <jthierry@redhat.com>
Date: Tue, 25 Aug 2020 13:47:41 +0100
Subject: objtool: Skip ORC entry creation for non-text sections

Orc generation is only done for text sections, but some instructions
can be found in non-text sections (e.g. .discard.text sections).

Skip setting their orc sections since their whole sections will be
skipped for orc generation.

Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/orc_gen.c | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'tools')

diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index e6b2363c2e03..22fe4398197f 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -18,6 +18,9 @@ int create_orc(struct objtool_file *file)
 		struct cfi_reg *cfa = &insn->cfi.cfa;
 		struct cfi_reg *bp = &insn->cfi.regs[CFI_BP];
 
+		if (!insn->sec->text)
+			continue;
+
 		orc->end = insn->cfi.end;
 
 		if (cfa->base == CFI_UNDEFINED) {
-- 
cgit v1.2.3


From 66734e32463bd1346466f92662feeaccef26e94f Mon Sep 17 00:00:00 2001
From: Julien Thierry <jthierry@redhat.com>
Date: Tue, 25 Aug 2020 13:47:42 +0100
Subject: objtool: Define 'struct orc_entry' only when needed

Implementation of ORC requires some definitions that are currently
provided by the target architecture headers. Do not depend on these
definitions when the orc subcommand is not implemented.

This avoid requiring arches with no orc implementation to provide dummy
orc definitions.

Signed-off-by: Julien Thierry <jthierry@redhat.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/Makefile | 4 ++++
 tools/objtool/arch.h   | 2 ++
 tools/objtool/check.h  | 2 ++
 3 files changed, 8 insertions(+)

(limited to 'tools')

diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index 7770edcda3a0..33d1e3ca8efd 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -55,6 +55,10 @@ ifeq ($(SRCARCH),x86)
 	SUBCMD_ORC := y
 endif
 
+ifeq ($(SUBCMD_ORC),y)
+	CFLAGS += -DINSN_USE_ORC
+endif
+
 export SUBCMD_CHECK SUBCMD_ORC
 export srctree OUTPUT CFLAGS SRCARCH AWK
 include $(srctree)/tools/build/Makefile.include
diff --git a/tools/objtool/arch.h b/tools/objtool/arch.h
index 2e2ce089b0e9..b18c5f61d42d 100644
--- a/tools/objtool/arch.h
+++ b/tools/objtool/arch.h
@@ -11,7 +11,9 @@
 #include "objtool.h"
 #include "cfi.h"
 
+#ifdef INSN_USE_ORC
 #include <asm/orc_types.h>
+#endif
 
 enum insn_type {
 	INSN_JUMP_CONDITIONAL,
diff --git a/tools/objtool/check.h b/tools/objtool/check.h
index 36d38b9153ac..6cac34542122 100644
--- a/tools/objtool/check.h
+++ b/tools/objtool/check.h
@@ -43,7 +43,9 @@ struct instruction {
 	struct symbol *func;
 	struct list_head stack_ops;
 	struct cfi_state cfi;
+#ifdef INSN_USE_ORC
 	struct orc_entry orc;
+#endif
 };
 
 struct instruction *find_insn(struct objtool_file *file,
-- 
cgit v1.2.3


From 3890b8d92710af75baedf291832cf40193b33454 Mon Sep 17 00:00:00 2001
From: Julien Thierry <jthierry@redhat.com>
Date: Fri, 4 Sep 2020 16:30:19 +0100
Subject: objtool: Group headers to check in a single list

In order to support multiple architectures and potentially different
sets of headers to compare against their kernel equivalent, it is
simpler to have all headers to check in a single list.

Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/sync-check.sh | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

(limited to 'tools')

diff --git a/tools/objtool/sync-check.sh b/tools/objtool/sync-check.sh
index aa099b21dffa..b5f526638f0a 100755
--- a/tools/objtool/sync-check.sh
+++ b/tools/objtool/sync-check.sh
@@ -1,14 +1,18 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
 
-FILES='
+FILES="
 arch/x86/include/asm/inat_types.h
 arch/x86/include/asm/orc_types.h
 arch/x86/include/asm/emulate_prefix.h
 arch/x86/lib/x86-opcode-map.txt
 arch/x86/tools/gen-insn-attr-x86.awk
 include/linux/static_call_types.h
-'
+arch/x86/include/asm/inat.h     -I '^#include [\"<]\(asm/\)*inat_types.h[\">]'
+arch/x86/include/asm/insn.h     -I '^#include [\"<]\(asm/\)*inat.h[\">]'
+arch/x86/lib/inat.c             -I '^#include [\"<]\(../include/\)*asm/insn.h[\">]'
+arch/x86/lib/insn.c             -I '^#include [\"<]\(../include/\)*asm/in\(at\|sn\).h[\">]' -I '^#include [\"<]\(../include/\)*asm/emulate_prefix.h[\">]'
+"
 
 check_2 () {
   file1=$1
@@ -41,11 +45,12 @@ fi
 
 cd ../..
 
-for i in $FILES; do
-  check $i
-done
+while read -r file_entry; do
+    if [ -z "$file_entry" ]; then
+	continue
+    fi
 
-check arch/x86/include/asm/inat.h     '-I "^#include [\"<]\(asm/\)*inat_types.h[\">]"'
-check arch/x86/include/asm/insn.h     '-I "^#include [\"<]\(asm/\)*inat.h[\">]"'
-check arch/x86/lib/inat.c             '-I "^#include [\"<]\(../include/\)*asm/insn.h[\">]"'
-check arch/x86/lib/insn.c             '-I "^#include [\"<]\(../include/\)*asm/in\(at\|sn\).h[\">]" -I "^#include [\"<]\(../include/\)*asm/emulate_prefix.h[\">]"'
+    check $file_entry
+done <<EOF
+$FILES
+EOF
-- 
cgit v1.2.3


From bb090fdb70ecc51c91e1d86345adae064caa06c8 Mon Sep 17 00:00:00 2001
From: Julien Thierry <jthierry@redhat.com>
Date: Fri, 4 Sep 2020 16:30:20 +0100
Subject: objtool: Make sync-check consider the target architecture

Do not take into account outdated headers unrelated to the build of the
current architecture.

[ jpoimboe: use $SRCARCH directly ]

Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/sync-check.sh | 7 +++++++
 1 file changed, 7 insertions(+)

(limited to 'tools')

diff --git a/tools/objtool/sync-check.sh b/tools/objtool/sync-check.sh
index b5f526638f0a..cea1c12607b9 100755
--- a/tools/objtool/sync-check.sh
+++ b/tools/objtool/sync-check.sh
@@ -1,6 +1,12 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
 
+if [ -z "$SRCARCH" ]; then
+	echo 'sync-check.sh: error: missing $SRCARCH environment variable' >&2
+	exit 1
+fi
+
+if [ "$SRCARCH" = "x86" ]; then
 FILES="
 arch/x86/include/asm/inat_types.h
 arch/x86/include/asm/orc_types.h
@@ -13,6 +19,7 @@ arch/x86/include/asm/insn.h     -I '^#include [\"<]\(asm/\)*inat.h[\">]'
 arch/x86/lib/inat.c             -I '^#include [\"<]\(../include/\)*asm/insn.h[\">]'
 arch/x86/lib/insn.c             -I '^#include [\"<]\(../include/\)*asm/in\(at\|sn\).h[\">]' -I '^#include [\"<]\(../include/\)*asm/emulate_prefix.h[\">]'
 "
+fi
 
 check_2 () {
   file1=$1
-- 
cgit v1.2.3


From c8ea0d672521ef663f0f9a77faa94d0d47102d77 Mon Sep 17 00:00:00 2001
From: Julien Thierry <jthierry@redhat.com>
Date: Fri, 4 Sep 2020 16:30:21 +0100
Subject: objtool: Move macros describing structures to arch-dependent code

Some macros are defined to describe the size and layout of structures
exception_table_entry, jump_entry and alt_instr. These values can vary
from one architecture to another.

Have the values be defined by arch specific code.

Suggested-by: Raphael Gault <raphael.gault@arm.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/arch/x86/include/arch_special.h | 20 ++++++++++++++++++++
 tools/objtool/special.c                       | 16 +---------------
 2 files changed, 21 insertions(+), 15 deletions(-)
 create mode 100644 tools/objtool/arch/x86/include/arch_special.h

(limited to 'tools')

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 000000000000..d818b2bffa02
--- /dev/null
+++ b/tools/objtool/arch/x86/include/arch_special.h
@@ -0,0 +1,20 @@
+/* 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 ALT_ENTRY_SIZE		13
+#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/special.c b/tools/objtool/special.c
index e893f1e48e44..b04f395de5de 100644
--- a/tools/objtool/special.c
+++ b/tools/objtool/special.c
@@ -14,21 +14,7 @@
 #include "builtin.h"
 #include "special.h"
 #include "warn.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 ALT_ENTRY_SIZE		13
-#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
+#include "arch_special.h"
 
 #define X86_FEATURE_POPCNT (4*32+23)
 #define X86_FEATURE_SMAP   (9*32+20)
-- 
cgit v1.2.3


From eda3dc905834dc9c99132f987f77b68cf53a8682 Mon Sep 17 00:00:00 2001
From: Julien Thierry <jthierry@redhat.com>
Date: Fri, 4 Sep 2020 16:30:22 +0100
Subject: objtool: Abstract alternative special case handling

Some alternatives associated with a specific feature need to be treated
in a special way. Since the features and how to treat them vary from one
architecture to another, move the special case handling to arch specific
code.

Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/arch/x86/Build     |  1 +
 tools/objtool/arch/x86/special.c | 37 +++++++++++++++++++++++++++++++++++++
 tools/objtool/objtool.h          |  2 ++
 tools/objtool/special.c          | 32 +++++---------------------------
 tools/objtool/special.h          |  2 ++
 tools/objtool/weak.c             |  2 --
 6 files changed, 47 insertions(+), 29 deletions(-)
 create mode 100644 tools/objtool/arch/x86/special.c

(limited to 'tools')

diff --git a/tools/objtool/arch/x86/Build b/tools/objtool/arch/x86/Build
index 7c5004008e97..9f7869b5c5e0 100644
--- a/tools/objtool/arch/x86/Build
+++ b/tools/objtool/arch/x86/Build
@@ -1,3 +1,4 @@
+objtool-y += special.o
 objtool-y += decode.o
 
 inat_tables_script = ../arch/x86/tools/gen-insn-attr-x86.awk
diff --git a/tools/objtool/arch/x86/special.c b/tools/objtool/arch/x86/special.c
new file mode 100644
index 000000000000..823561e4015c
--- /dev/null
+++ b/tools/objtool/arch/x86/special.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include "../../special.h"
+#include "../../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 (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;
+	}
+}
diff --git a/tools/objtool/objtool.h b/tools/objtool/objtool.h
index a635f68a9b09..4125d4578b23 100644
--- a/tools/objtool/objtool.h
+++ b/tools/objtool/objtool.h
@@ -12,6 +12,8 @@
 
 #include "elf.h"
 
+#define __weak __attribute__((weak))
+
 struct objtool_file {
 	struct elf *elf;
 	struct list_head insn_list;
diff --git a/tools/objtool/special.c b/tools/objtool/special.c
index b04f395de5de..1a2420febd08 100644
--- a/tools/objtool/special.c
+++ b/tools/objtool/special.c
@@ -16,9 +16,6 @@
 #include "warn.h"
 #include "arch_special.h"
 
-#define X86_FEATURE_POPCNT (4*32+23)
-#define X86_FEATURE_SMAP   (9*32+20)
-
 struct special_entry {
 	const char *sec;
 	bool group, jump_or_nop;
@@ -54,6 +51,10 @@ struct special_entry entries[] = {
 	{},
 };
 
+void __weak arch_handle_alternative(unsigned short feature, struct special_alt *alt)
+{
+}
+
 static int get_alt_entry(struct elf *elf, struct special_entry *entry,
 			 struct section *sec, int idx,
 			 struct special_alt *alt)
@@ -78,30 +79,7 @@ static int get_alt_entry(struct elf *elf, struct special_entry *entry,
 
 		feature = *(unsigned short *)(sec->data->d_buf + offset +
 					      entry->feature);
-
-		/*
-		 * It has been requested that we don't validate the !POPCNT
-		 * feature path which is a "very very small percentage of
-		 * machines".
-		 */
-		if (feature == X86_FEATURE_POPCNT)
-			alt->skip_orig = true;
-
-		/*
-		 * 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 (feature == X86_FEATURE_SMAP) {
-			if (uaccess)
-				alt->skip_orig = true;
-			else
-				alt->skip_alt = true;
-		}
+		arch_handle_alternative(feature, alt);
 	}
 
 	orig_reloc = find_reloc_by_dest(elf, sec, offset + entry->orig);
diff --git a/tools/objtool/special.h b/tools/objtool/special.h
index 35061530e46e..44da89afeda2 100644
--- a/tools/objtool/special.h
+++ b/tools/objtool/special.h
@@ -28,4 +28,6 @@ struct special_alt {
 
 int special_get_alts(struct elf *elf, struct list_head *alts);
 
+void arch_handle_alternative(unsigned short feature, struct special_alt *alt);
+
 #endif /* _SPECIAL_H */
diff --git a/tools/objtool/weak.c b/tools/objtool/weak.c
index 29180d599b08..7843e9a7a72f 100644
--- a/tools/objtool/weak.c
+++ b/tools/objtool/weak.c
@@ -9,8 +9,6 @@
 #include <errno.h>
 #include "objtool.h"
 
-#define __weak __attribute__((weak))
-
 #define UNSUPPORTED(name)						\
 ({									\
 	fprintf(stderr, "error: objtool: " name " not implemented\n");	\
-- 
cgit v1.2.3


From 45245f51f9a4b9a883a8c94468473c1de9b88153 Mon Sep 17 00:00:00 2001
From: Julien Thierry <jthierry@redhat.com>
Date: Fri, 4 Sep 2020 16:30:23 +0100
Subject: objtool: Make relocation in alternative handling arch dependent

As pointed out by the comment in handle_group_alt(), support of
relocation for instructions in an alternative group depends on whether
arch specific kernel code handles it.

So, let objtool arch specific code decide whether a relocation for
the alternative section should be accepted.

Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/arch/x86/special.c | 13 +++++++++++++
 tools/objtool/check.c            | 19 ++++++-------------
 tools/objtool/check.h            |  6 ++++++
 tools/objtool/special.h          |  4 ++++
 4 files changed, 29 insertions(+), 13 deletions(-)

(limited to 'tools')

diff --git a/tools/objtool/arch/x86/special.c b/tools/objtool/arch/x86/special.c
index 823561e4015c..34e0e162e6fd 100644
--- a/tools/objtool/arch/x86/special.c
+++ b/tools/objtool/arch/x86/special.c
@@ -35,3 +35,16 @@ void arch_handle_alternative(unsigned short feature, struct special_alt *alt)
 		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_static_jump(insn));
+}
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 4afc2d5465b9..1796a7c464eb 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -110,12 +110,6 @@ static struct instruction *prev_insn_same_sym(struct objtool_file *file,
 	for (insn = next_insn_same_sec(file, insn); insn;		\
 	     insn = next_insn_same_sec(file, insn))
 
-static bool is_static_jump(struct instruction *insn)
-{
-	return insn->type == INSN_JUMP_CONDITIONAL ||
-	       insn->type == INSN_JUMP_UNCONDITIONAL;
-}
-
 static bool is_sibling_call(struct instruction *insn)
 {
 	/* An indirect jump is either a sibling call or a jump to a table. */
@@ -972,6 +966,8 @@ static int handle_group_alt(struct objtool_file *file,
 	alt_group = alt_group_next_index++;
 	insn = *new_insn;
 	sec_for_each_insn_from(file, insn) {
+		struct reloc *alt_reloc;
+
 		if (insn->offset >= special_alt->new_off + special_alt->new_len)
 			break;
 
@@ -988,14 +984,11 @@ static int handle_group_alt(struct objtool_file *file,
 		 * .altinstr_replacement section, unless the arch's
 		 * alternatives code can adjust the relative offsets
 		 * accordingly.
-		 *
-		 * The x86 alternatives code adjusts the offsets only when it
-		 * encounters a branch instruction at the very beginning of the
-		 * replacement group.
 		 */
-		if ((insn->offset != special_alt->new_off ||
-		    (insn->type != INSN_CALL && !is_static_jump(insn))) &&
-		    find_reloc_by_dest_range(file->elf, insn->sec, insn->offset, insn->len)) {
+		alt_reloc = find_reloc_by_dest_range(file->elf, insn->sec,
+						   insn->offset, insn->len);
+		if (alt_reloc &&
+		    !arch_support_alt_relocation(special_alt, insn, alt_reloc)) {
 
 			WARN_FUNC("unsupported relocation in alternatives section",
 				  insn->sec, insn->offset);
diff --git a/tools/objtool/check.h b/tools/objtool/check.h
index 6cac34542122..1de1188b23cd 100644
--- a/tools/objtool/check.h
+++ b/tools/objtool/check.h
@@ -48,6 +48,12 @@ struct instruction {
 #endif
 };
 
+static inline bool is_static_jump(struct instruction *insn)
+{
+	return insn->type == INSN_JUMP_CONDITIONAL ||
+	       insn->type == INSN_JUMP_UNCONDITIONAL;
+}
+
 struct instruction *find_insn(struct objtool_file *file,
 			      struct section *sec, unsigned long offset);
 
diff --git a/tools/objtool/special.h b/tools/objtool/special.h
index 44da89afeda2..1dc1bb3e74c6 100644
--- a/tools/objtool/special.h
+++ b/tools/objtool/special.h
@@ -7,6 +7,7 @@
 #define _SPECIAL_H
 
 #include <stdbool.h>
+#include "check.h"
 #include "elf.h"
 
 struct special_alt {
@@ -30,4 +31,7 @@ int special_get_alts(struct elf *elf, struct list_head *alts);
 
 void arch_handle_alternative(unsigned short feature, struct special_alt *alt);
 
+bool arch_support_alt_relocation(struct special_alt *special_alt,
+				 struct instruction *insn,
+				 struct reloc *reloc);
 #endif /* _SPECIAL_H */
-- 
cgit v1.2.3


From d871f7b5a6a2a30f4eba577fd56941fa3657e394 Mon Sep 17 00:00:00 2001
From: Raphael Gault <raphael.gault@arm.com>
Date: Fri, 4 Sep 2020 16:30:24 +0100
Subject: objtool: Refactor jump table code to support other architectures

The way to identify jump tables and retrieve all the data necessary to
handle the different execution branches is not the same on all
architectures.  In order to be able to add other architecture support,
define an arch-dependent function to process jump-tables.

Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Raphael Gault <raphael.gault@arm.com>
[J.T.: Move arm64 bits out of this patch,
       Have only one function to find the start of the jump table,
       for now assume that the jump table format will be the same as
       x86]
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/arch/x86/special.c | 95 ++++++++++++++++++++++++++++++++++++++++
 tools/objtool/check.c            | 90 ++-----------------------------------
 tools/objtool/check.h            |  1 -
 tools/objtool/special.h          |  4 ++
 4 files changed, 103 insertions(+), 87 deletions(-)

(limited to 'tools')

diff --git a/tools/objtool/arch/x86/special.c b/tools/objtool/arch/x86/special.c
index 34e0e162e6fd..fd4af88c0ea5 100644
--- a/tools/objtool/arch/x86/special.c
+++ b/tools/objtool/arch/x86/special.c
@@ -1,4 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
+#include <string.h>
+
 #include "../../special.h"
 #include "../../builtin.h"
 
@@ -48,3 +50,96 @@ bool arch_support_alt_relocation(struct special_alt *special_alt,
 	return insn->offset == special_alt->new_off &&
 	       (insn->type == INSN_CALL || is_static_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;
+}
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 1796a7c464eb..a94ad88d036c 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -20,8 +20,6 @@
 
 #define FAKE_JUMP_OFFSET -1
 
-#define C_JUMP_TABLE_SECTION ".rodata..c_jump_table"
-
 struct alternative {
 	struct list_head list;
 	struct instruction *insn;
@@ -1190,56 +1188,15 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn,
 }
 
 /*
- * find_jump_table() - Given a dynamic jump, find the switch jump table in
- * .rodata associated with it.
- *
- * There are 3 basic 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.
+ * find_jump_table() - Given a dynamic jump, find the switch jump table
+ * associated with it.
  */
 static struct reloc *find_jump_table(struct objtool_file *file,
 				      struct symbol *func,
 				      struct instruction *insn)
 {
-	struct reloc *text_reloc, *table_reloc;
+	struct reloc *table_reloc;
 	struct instruction *dest_insn, *orig_insn = insn;
-	struct section *table_sec;
-	unsigned long table_offset;
 
 	/*
 	 * Backward search using the @first_jump_src links, these help avoid
@@ -1260,52 +1217,13 @@ static struct reloc *find_jump_table(struct objtool_file *file,
 		     insn->jump_dest->offset > orig_insn->offset))
 		    break;
 
-		/* 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)
-			continue;
-
-		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))
-			continue;
-
-		/*
-		 * Each table entry has a reloc associated with it.  The reloc
-		 * should reference text in the same function as the original
-		 * instruction.
-		 */
-		table_reloc = find_reloc_by_dest(file->elf, table_sec, table_offset);
+		table_reloc = arch_find_switch_table(file, insn);
 		if (!table_reloc)
 			continue;
 		dest_insn = find_insn(file, table_reloc->sym->sec, table_reloc->addend);
 		if (!dest_insn || !dest_insn->func || dest_insn->func->pfunc != func)
 			continue;
 
-		/*
-		 * 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 table_reloc;
 	}
 
diff --git a/tools/objtool/check.h b/tools/objtool/check.h
index 1de1188b23cd..5ec00a4b891b 100644
--- a/tools/objtool/check.h
+++ b/tools/objtool/check.h
@@ -66,5 +66,4 @@ struct instruction *find_insn(struct objtool_file *file,
 			insn->sec == sec;				\
 	     insn = list_next_entry(insn, list))
 
-
 #endif /* _CHECK_H */
diff --git a/tools/objtool/special.h b/tools/objtool/special.h
index 1dc1bb3e74c6..abddf38ef334 100644
--- a/tools/objtool/special.h
+++ b/tools/objtool/special.h
@@ -10,6 +10,8 @@
 #include "check.h"
 #include "elf.h"
 
+#define C_JUMP_TABLE_SECTION ".rodata..c_jump_table"
+
 struct special_alt {
 	struct list_head list;
 
@@ -34,4 +36,6 @@ void arch_handle_alternative(unsigned short feature, struct special_alt *alt);
 bool arch_support_alt_relocation(struct special_alt *special_alt,
 				 struct instruction *insn,
 				 struct reloc *reloc);
+struct reloc *arch_find_switch_table(struct objtool_file *file,
+				    struct instruction *insn);
 #endif /* _SPECIAL_H */
-- 
cgit v1.2.3


From ee819aedf34a8f35cd54ee3967c7beb4d1d4a635 Mon Sep 17 00:00:00 2001
From: Julien Thierry <jthierry@redhat.com>
Date: Fri, 4 Sep 2020 16:30:27 +0100
Subject: objtool: Make unwind hint definitions available to other
 architectures

Unwind hints are useful to provide objtool with information about stack
states in non-standard functions/code.

While the type of information being provided might be very arch
specific, the mechanism to provide the information can be useful for
other architectures.

Move the relevant unwint hint definitions for all architectures to
see.

[ jpoimboe: REGS_IRET -> REGS_PARTIAL ]

Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 arch/x86/include/asm/orc_types.h       |  34 ---------
 arch/x86/include/asm/unwind_hints.h    |  56 +++-----------
 arch/x86/kernel/unwind_orc.c           |  11 +--
 include/linux/objtool.h                |  88 ++++++++++++++++++++++
 tools/arch/x86/include/asm/orc_types.h |  34 ---------
 tools/include/linux/objtool.h          | 129 +++++++++++++++++++++++++++++++++
 tools/objtool/check.c                  |   4 +-
 tools/objtool/orc_dump.c               |   9 ++-
 tools/objtool/orc_gen.c                |   5 +-
 tools/objtool/sync-check.sh            |   4 +-
 10 files changed, 249 insertions(+), 125 deletions(-)
 create mode 100644 tools/include/linux/objtool.h

(limited to 'tools')

diff --git a/arch/x86/include/asm/orc_types.h b/arch/x86/include/asm/orc_types.h
index d25534940bde..fdbffec4cfde 100644
--- a/arch/x86/include/asm/orc_types.h
+++ b/arch/x86/include/asm/orc_types.h
@@ -39,27 +39,6 @@
 #define ORC_REG_SP_INDIRECT		9
 #define ORC_REG_MAX			15
 
-/*
- * ORC_TYPE_CALL: Indicates that sp_reg+sp_offset resolves to PREV_SP (the
- * caller's SP right before it made the call).  Used for all callable
- * functions, i.e. all C code and all callable asm functions.
- *
- * ORC_TYPE_REGS: Used in entry code to indicate that sp_reg+sp_offset points
- * to a fully populated pt_regs from a syscall, interrupt, or exception.
- *
- * ORC_TYPE_REGS_IRET: Used in entry code to indicate that sp_reg+sp_offset
- * points to the iret return frame.
- *
- * The UNWIND_HINT macros are used only for the unwind_hint struct.  They
- * aren't used in struct orc_entry due to size and complexity constraints.
- * Objtool converts them to real types when it converts the hints to orc
- * entries.
- */
-#define ORC_TYPE_CALL			0
-#define ORC_TYPE_REGS			1
-#define ORC_TYPE_REGS_IRET		2
-#define UNWIND_HINT_TYPE_RET_OFFSET	3
-
 #ifndef __ASSEMBLY__
 /*
  * This struct is more or less a vastly simplified version of the DWARF Call
@@ -78,19 +57,6 @@ struct orc_entry {
 	unsigned	end:1;
 } __packed;
 
-/*
- * This struct is used by asm and inline asm code to manually annotate the
- * location of registers on the stack for the ORC unwinder.
- *
- * Type can be either ORC_TYPE_* or UNWIND_HINT_TYPE_*.
- */
-struct unwind_hint {
-	u32		ip;
-	s16		sp_offset;
-	u8		sp_reg;
-	u8		type;
-	u8		end;
-};
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ORC_TYPES_H */
diff --git a/arch/x86/include/asm/unwind_hints.h b/arch/x86/include/asm/unwind_hints.h
index 7d903fdb3f43..664d4610d700 100644
--- a/arch/x86/include/asm/unwind_hints.h
+++ b/arch/x86/include/asm/unwind_hints.h
@@ -1,51 +1,17 @@
 #ifndef _ASM_X86_UNWIND_HINTS_H
 #define _ASM_X86_UNWIND_HINTS_H
 
+#include <linux/objtool.h>
+
 #include "orc_types.h"
 
 #ifdef __ASSEMBLY__
 
-/*
- * In asm, there are two kinds of code: normal C-type callable functions and
- * the rest.  The normal callable functions can be called by other code, and
- * don't do anything unusual with the stack.  Such normal callable functions
- * are annotated with the ENTRY/ENDPROC macros.  Most asm code falls in this
- * category.  In this case, no special debugging annotations are needed because
- * objtool can automatically generate the ORC data for the ORC unwinder to read
- * at runtime.
- *
- * Anything which doesn't fall into the above category, such as syscall and
- * interrupt handlers, tends to not be called directly by other functions, and
- * often does unusual non-C-function-type things with the stack pointer.  Such
- * code needs to be annotated such that objtool can understand it.  The
- * following CFI hint macros are for this type of code.
- *
- * These macros provide hints to objtool about the state of the stack at each
- * instruction.  Objtool starts from the hints and follows the code flow,
- * making automatic CFI adjustments when it sees pushes and pops, filling out
- * the debuginfo as necessary.  It will also warn if it sees any
- * inconsistencies.
- */
-.macro UNWIND_HINT sp_reg=ORC_REG_SP sp_offset=0 type=ORC_TYPE_CALL end=0
-#ifdef CONFIG_STACK_VALIDATION
-.Lunwind_hint_ip_\@:
-	.pushsection .discard.unwind_hints
-		/* struct unwind_hint */
-		.long .Lunwind_hint_ip_\@ - .
-		.short \sp_offset
-		.byte \sp_reg
-		.byte \type
-		.byte \end
-		.balign 4
-	.popsection
-#endif
-.endm
-
 .macro UNWIND_HINT_EMPTY
-	UNWIND_HINT sp_reg=ORC_REG_UNDEFINED end=1
+	UNWIND_HINT sp_reg=ORC_REG_UNDEFINED type=UNWIND_HINT_TYPE_CALL end=1
 .endm
 
-.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 iret=0
+.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 partial=0
 	.if \base == %rsp
 		.if \indirect
 			.set sp_reg, ORC_REG_SP_INDIRECT
@@ -66,24 +32,24 @@
 
 	.set sp_offset, \offset
 
-	.if \iret
-		.set type, ORC_TYPE_REGS_IRET
+	.if \partial
+		.set type, UNWIND_HINT_TYPE_REGS_PARTIAL
 	.elseif \extra == 0
-		.set type, ORC_TYPE_REGS_IRET
+		.set type, UNWIND_HINT_TYPE_REGS_PARTIAL
 		.set sp_offset, \offset + (16*8)
 	.else
-		.set type, ORC_TYPE_REGS
+		.set type, UNWIND_HINT_TYPE_REGS
 	.endif
 
 	UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type
 .endm
 
 .macro UNWIND_HINT_IRET_REGS base=%rsp offset=0
-	UNWIND_HINT_REGS base=\base offset=\offset iret=1
+	UNWIND_HINT_REGS base=\base offset=\offset partial=1
 .endm
 
 .macro UNWIND_HINT_FUNC sp_offset=8
-	UNWIND_HINT sp_offset=\sp_offset
+	UNWIND_HINT sp_reg=ORC_REG_SP sp_offset=\sp_offset type=UNWIND_HINT_TYPE_CALL
 .endm
 
 /*
@@ -92,7 +58,7 @@
  * initial_func_cfi.
  */
 .macro UNWIND_HINT_RET_OFFSET sp_offset=8
-	UNWIND_HINT type=UNWIND_HINT_TYPE_RET_OFFSET sp_offset=\sp_offset
+	UNWIND_HINT sp_reg=ORC_REG_SP type=UNWIND_HINT_TYPE_RET_OFFSET sp_offset=\sp_offset
 .endm
 
 #endif /* __ASSEMBLY__ */
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index ec88bbe08a32..6a339ce328e0 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-only
+#include <linux/objtool.h>
 #include <linux/module.h>
 #include <linux/sort.h>
 #include <asm/ptrace.h>
@@ -127,12 +128,12 @@ static struct orc_entry null_orc_entry = {
 	.sp_offset = sizeof(long),
 	.sp_reg = ORC_REG_SP,
 	.bp_reg = ORC_REG_UNDEFINED,
-	.type = ORC_TYPE_CALL
+	.type = UNWIND_HINT_TYPE_CALL
 };
 
 /* Fake frame pointer entry -- used as a fallback for generated code */
 static struct orc_entry orc_fp_entry = {
-	.type		= ORC_TYPE_CALL,
+	.type		= UNWIND_HINT_TYPE_CALL,
 	.sp_reg		= ORC_REG_BP,
 	.sp_offset	= 16,
 	.bp_reg		= ORC_REG_PREV_SP,
@@ -531,7 +532,7 @@ bool unwind_next_frame(struct unwind_state *state)
 
 	/* Find IP, SP and possibly regs: */
 	switch (orc->type) {
-	case ORC_TYPE_CALL:
+	case UNWIND_HINT_TYPE_CALL:
 		ip_p = sp - sizeof(long);
 
 		if (!deref_stack_reg(state, ip_p, &state->ip))
@@ -546,7 +547,7 @@ bool unwind_next_frame(struct unwind_state *state)
 		state->signal = false;
 		break;
 
-	case ORC_TYPE_REGS:
+	case UNWIND_HINT_TYPE_REGS:
 		if (!deref_stack_regs(state, sp, &state->ip, &state->sp)) {
 			orc_warn_current("can't access registers at %pB\n",
 					 (void *)orig_ip);
@@ -559,7 +560,7 @@ bool unwind_next_frame(struct unwind_state *state)
 		state->signal = true;
 		break;
 
-	case ORC_TYPE_REGS_IRET:
+	case UNWIND_HINT_TYPE_REGS_PARTIAL:
 		if (!deref_stack_iret_regs(state, sp, &state->ip, &state->sp)) {
 			orc_warn_current("can't access iret registers at %pB\n",
 					 (void *)orig_ip);
diff --git a/include/linux/objtool.h b/include/linux/objtool.h
index 15e9997a9fb4..ab82c793c897 100644
--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -2,9 +2,55 @@
 #ifndef _LINUX_OBJTOOL_H
 #define _LINUX_OBJTOOL_H
 
+#ifndef __ASSEMBLY__
+
+#include <linux/types.h>
+
+/*
+ * This struct is used by asm and inline asm code to manually annotate the
+ * location of registers on the stack.
+ */
+struct unwind_hint {
+	u32		ip;
+	s16		sp_offset;
+	u8		sp_reg;
+	u8		type;
+	u8		end;
+};
+#endif
+
+/*
+ * UNWIND_HINT_TYPE_CALL: Indicates that sp_reg+sp_offset resolves to PREV_SP
+ * (the caller's SP right before it made the call).  Used for all callable
+ * functions, i.e. all C code and all callable asm functions.
+ *
+ * UNWIND_HINT_TYPE_REGS: Used in entry code to indicate that sp_reg+sp_offset
+ * points to a fully populated pt_regs from a syscall, interrupt, or exception.
+ *
+ * UNWIND_HINT_TYPE_REGS_PARTIAL: Used in entry code to indicate that
+ * sp_reg+sp_offset points to the iret return frame.
+ */
+#define UNWIND_HINT_TYPE_CALL		0
+#define UNWIND_HINT_TYPE_REGS		1
+#define UNWIND_HINT_TYPE_REGS_PARTIAL	2
+#define UNWIND_HINT_TYPE_RET_OFFSET	3
+
 #ifdef CONFIG_STACK_VALIDATION
 
 #ifndef __ASSEMBLY__
+
+#define UNWIND_HINT(sp_reg, sp_offset, type, end)		\
+	"987: \n\t"						\
+	".pushsection .discard.unwind_hints\n\t"		\
+	/* struct unwind_hint */				\
+	".long 987b - .\n\t"					\
+	".short " __stringify(sp_offset) "\n\t"			\
+	".byte " __stringify(sp_reg) "\n\t"			\
+	".byte " __stringify(type) "\n\t"			\
+	".byte " __stringify(end) "\n\t"			\
+	".balign 4 \n\t"					\
+	".popsection\n\t"
+
 /*
  * This macro marks the given function's stack frame as "non-standard", which
  * tells objtool to ignore the function when doing stack metadata validation.
@@ -29,12 +75,54 @@
 	.long 999b;						\
 	.popsection;
 
+/*
+ * In asm, there are two kinds of code: normal C-type callable functions and
+ * the rest.  The normal callable functions can be called by other code, and
+ * don't do anything unusual with the stack.  Such normal callable functions
+ * are annotated with the ENTRY/ENDPROC macros.  Most asm code falls in this
+ * category.  In this case, no special debugging annotations are needed because
+ * objtool can automatically generate the ORC data for the ORC unwinder to read
+ * at runtime.
+ *
+ * Anything which doesn't fall into the above category, such as syscall and
+ * interrupt handlers, tends to not be called directly by other functions, and
+ * often does unusual non-C-function-type things with the stack pointer.  Such
+ * code needs to be annotated such that objtool can understand it.  The
+ * following CFI hint macros are for this type of code.
+ *
+ * These macros provide hints to objtool about the state of the stack at each
+ * instruction.  Objtool starts from the hints and follows the code flow,
+ * making automatic CFI adjustments when it sees pushes and pops, filling out
+ * the debuginfo as necessary.  It will also warn if it sees any
+ * inconsistencies.
+ */
+.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
+.Lunwind_hint_ip_\@:
+	.pushsection .discard.unwind_hints
+		/* struct unwind_hint */
+		.long .Lunwind_hint_ip_\@ - .
+		.short \sp_offset
+		.byte \sp_reg
+		.byte \type
+		.byte \end
+		.balign 4
+	.popsection
+.endm
+
 #endif /* __ASSEMBLY__ */
 
 #else /* !CONFIG_STACK_VALIDATION */
 
+#ifndef __ASSEMBLY__
+
+#define UNWIND_HINT(sp_reg, sp_offset, type, end)	\
+	"\n\t"
 #define STACK_FRAME_NON_STANDARD(func)
+#else
 #define ANNOTATE_INTRA_FUNCTION_CALL
+.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
+.endm
+#endif
 
 #endif /* CONFIG_STACK_VALIDATION */
 
diff --git a/tools/arch/x86/include/asm/orc_types.h b/tools/arch/x86/include/asm/orc_types.h
index d25534940bde..fdbffec4cfde 100644
--- a/tools/arch/x86/include/asm/orc_types.h
+++ b/tools/arch/x86/include/asm/orc_types.h
@@ -39,27 +39,6 @@
 #define ORC_REG_SP_INDIRECT		9
 #define ORC_REG_MAX			15
 
-/*
- * ORC_TYPE_CALL: Indicates that sp_reg+sp_offset resolves to PREV_SP (the
- * caller's SP right before it made the call).  Used for all callable
- * functions, i.e. all C code and all callable asm functions.
- *
- * ORC_TYPE_REGS: Used in entry code to indicate that sp_reg+sp_offset points
- * to a fully populated pt_regs from a syscall, interrupt, or exception.
- *
- * ORC_TYPE_REGS_IRET: Used in entry code to indicate that sp_reg+sp_offset
- * points to the iret return frame.
- *
- * The UNWIND_HINT macros are used only for the unwind_hint struct.  They
- * aren't used in struct orc_entry due to size and complexity constraints.
- * Objtool converts them to real types when it converts the hints to orc
- * entries.
- */
-#define ORC_TYPE_CALL			0
-#define ORC_TYPE_REGS			1
-#define ORC_TYPE_REGS_IRET		2
-#define UNWIND_HINT_TYPE_RET_OFFSET	3
-
 #ifndef __ASSEMBLY__
 /*
  * This struct is more or less a vastly simplified version of the DWARF Call
@@ -78,19 +57,6 @@ struct orc_entry {
 	unsigned	end:1;
 } __packed;
 
-/*
- * This struct is used by asm and inline asm code to manually annotate the
- * location of registers on the stack for the ORC unwinder.
- *
- * Type can be either ORC_TYPE_* or UNWIND_HINT_TYPE_*.
- */
-struct unwind_hint {
-	u32		ip;
-	s16		sp_offset;
-	u8		sp_reg;
-	u8		type;
-	u8		end;
-};
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ORC_TYPES_H */
diff --git a/tools/include/linux/objtool.h b/tools/include/linux/objtool.h
new file mode 100644
index 000000000000..ab82c793c897
--- /dev/null
+++ b/tools/include/linux/objtool.h
@@ -0,0 +1,129 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_OBJTOOL_H
+#define _LINUX_OBJTOOL_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/types.h>
+
+/*
+ * This struct is used by asm and inline asm code to manually annotate the
+ * location of registers on the stack.
+ */
+struct unwind_hint {
+	u32		ip;
+	s16		sp_offset;
+	u8		sp_reg;
+	u8		type;
+	u8		end;
+};
+#endif
+
+/*
+ * UNWIND_HINT_TYPE_CALL: Indicates that sp_reg+sp_offset resolves to PREV_SP
+ * (the caller's SP right before it made the call).  Used for all callable
+ * functions, i.e. all C code and all callable asm functions.
+ *
+ * UNWIND_HINT_TYPE_REGS: Used in entry code to indicate that sp_reg+sp_offset
+ * points to a fully populated pt_regs from a syscall, interrupt, or exception.
+ *
+ * UNWIND_HINT_TYPE_REGS_PARTIAL: Used in entry code to indicate that
+ * sp_reg+sp_offset points to the iret return frame.
+ */
+#define UNWIND_HINT_TYPE_CALL		0
+#define UNWIND_HINT_TYPE_REGS		1
+#define UNWIND_HINT_TYPE_REGS_PARTIAL	2
+#define UNWIND_HINT_TYPE_RET_OFFSET	3
+
+#ifdef CONFIG_STACK_VALIDATION
+
+#ifndef __ASSEMBLY__
+
+#define UNWIND_HINT(sp_reg, sp_offset, type, end)		\
+	"987: \n\t"						\
+	".pushsection .discard.unwind_hints\n\t"		\
+	/* struct unwind_hint */				\
+	".long 987b - .\n\t"					\
+	".short " __stringify(sp_offset) "\n\t"			\
+	".byte " __stringify(sp_reg) "\n\t"			\
+	".byte " __stringify(type) "\n\t"			\
+	".byte " __stringify(end) "\n\t"			\
+	".balign 4 \n\t"					\
+	".popsection\n\t"
+
+/*
+ * This macro marks the given function's stack frame as "non-standard", which
+ * tells objtool to ignore the function when doing stack metadata validation.
+ * It should only be used in special cases where you're 100% sure it won't
+ * affect the reliability of frame pointers and kernel stack traces.
+ *
+ * For more information, see tools/objtool/Documentation/stack-validation.txt.
+ */
+#define STACK_FRAME_NON_STANDARD(func) \
+	static void __used __section(.discard.func_stack_frame_non_standard) \
+		*__func_stack_frame_non_standard_##func = func
+
+#else /* __ASSEMBLY__ */
+
+/*
+ * This macro indicates that the following intra-function call is valid.
+ * Any non-annotated intra-function call will cause objtool to issue a warning.
+ */
+#define ANNOTATE_INTRA_FUNCTION_CALL				\
+	999:							\
+	.pushsection .discard.intra_function_calls;		\
+	.long 999b;						\
+	.popsection;
+
+/*
+ * In asm, there are two kinds of code: normal C-type callable functions and
+ * the rest.  The normal callable functions can be called by other code, and
+ * don't do anything unusual with the stack.  Such normal callable functions
+ * are annotated with the ENTRY/ENDPROC macros.  Most asm code falls in this
+ * category.  In this case, no special debugging annotations are needed because
+ * objtool can automatically generate the ORC data for the ORC unwinder to read
+ * at runtime.
+ *
+ * Anything which doesn't fall into the above category, such as syscall and
+ * interrupt handlers, tends to not be called directly by other functions, and
+ * often does unusual non-C-function-type things with the stack pointer.  Such
+ * code needs to be annotated such that objtool can understand it.  The
+ * following CFI hint macros are for this type of code.
+ *
+ * These macros provide hints to objtool about the state of the stack at each
+ * instruction.  Objtool starts from the hints and follows the code flow,
+ * making automatic CFI adjustments when it sees pushes and pops, filling out
+ * the debuginfo as necessary.  It will also warn if it sees any
+ * inconsistencies.
+ */
+.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
+.Lunwind_hint_ip_\@:
+	.pushsection .discard.unwind_hints
+		/* struct unwind_hint */
+		.long .Lunwind_hint_ip_\@ - .
+		.short \sp_offset
+		.byte \sp_reg
+		.byte \type
+		.byte \end
+		.balign 4
+	.popsection
+.endm
+
+#endif /* __ASSEMBLY__ */
+
+#else /* !CONFIG_STACK_VALIDATION */
+
+#ifndef __ASSEMBLY__
+
+#define UNWIND_HINT(sp_reg, sp_offset, type, end)	\
+	"\n\t"
+#define STACK_FRAME_NON_STANDARD(func)
+#else
+#define ANNOTATE_INTRA_FUNCTION_CALL
+.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
+.endm
+#endif
+
+#endif /* CONFIG_STACK_VALIDATION */
+
+#endif /* _LINUX_OBJTOOL_H */
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index a94ad88d036c..95c6e0d31c0a 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -14,6 +14,7 @@
 #include "warn.h"
 #include "arch_elf.h"
 
+#include <linux/objtool.h>
 #include <linux/hashtable.h>
 #include <linux/kernel.h>
 #include <linux/static_call_types.h>
@@ -1805,7 +1806,8 @@ static int update_cfi_state(struct instruction *insn, struct cfi_state *cfi,
 		return 0;
 	}
 
-	if (cfi->type == ORC_TYPE_REGS || cfi->type == ORC_TYPE_REGS_IRET)
+	if (cfi->type == UNWIND_HINT_TYPE_REGS ||
+	    cfi->type == UNWIND_HINT_TYPE_REGS_PARTIAL)
 		return update_cfi_state_regs(insn, cfi, op);
 
 	switch (op->dest.type) {
diff --git a/tools/objtool/orc_dump.c b/tools/objtool/orc_dump.c
index fca46e006fc2..5e6a95368d35 100644
--- a/tools/objtool/orc_dump.c
+++ b/tools/objtool/orc_dump.c
@@ -4,6 +4,7 @@
  */
 
 #include <unistd.h>
+#include <linux/objtool.h>
 #include <asm/orc_types.h>
 #include "objtool.h"
 #include "warn.h"
@@ -37,12 +38,12 @@ static const char *reg_name(unsigned int reg)
 static const char *orc_type_name(unsigned int type)
 {
 	switch (type) {
-	case ORC_TYPE_CALL:
+	case UNWIND_HINT_TYPE_CALL:
 		return "call";
-	case ORC_TYPE_REGS:
+	case UNWIND_HINT_TYPE_REGS:
 		return "regs";
-	case ORC_TYPE_REGS_IRET:
-		return "iret";
+	case UNWIND_HINT_TYPE_REGS_PARTIAL:
+		return "regs (partial)";
 	default:
 		return "?";
 	}
diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index 22fe4398197f..235663b96adc 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -6,6 +6,9 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include <linux/objtool.h>
+#include <asm/orc_types.h>
+
 #include "check.h"
 #include "warn.h"
 
@@ -146,7 +149,7 @@ int create_orc_sections(struct objtool_file *file)
 	struct orc_entry empty = {
 		.sp_reg = ORC_REG_UNDEFINED,
 		.bp_reg  = ORC_REG_UNDEFINED,
-		.type    = ORC_TYPE_CALL,
+		.type    = UNWIND_HINT_TYPE_CALL,
 	};
 
 	sec = find_section_by_name(file->elf, ".orc_unwind");
diff --git a/tools/objtool/sync-check.sh b/tools/objtool/sync-check.sh
index cea1c12607b9..606a4b5e929f 100755
--- a/tools/objtool/sync-check.sh
+++ b/tools/objtool/sync-check.sh
@@ -6,8 +6,10 @@ if [ -z "$SRCARCH" ]; then
 	exit 1
 fi
 
+FILES="include/linux/objtool.h"
+
 if [ "$SRCARCH" = "x86" ]; then
-FILES="
+FILES="$FILES
 arch/x86/include/asm/inat_types.h
 arch/x86/include/asm/orc_types.h
 arch/x86/include/asm/emulate_prefix.h
-- 
cgit v1.2.3


From edea9e6bcbeaa41718b022a8b99ffddef2330bbc Mon Sep 17 00:00:00 2001
From: Julien Thierry <jthierry@redhat.com>
Date: Fri, 4 Sep 2020 16:30:28 +0100
Subject: objtool: Decode unwind hint register depending on architecture

The set of registers that can be included in an unwind hint and their
encoding will depend on the architecture. Have arch specific code to
decode that register.

Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/arch.h            |  2 ++
 tools/objtool/arch/x86/decode.c | 37 +++++++++++++++++++++++++++++++++++++
 tools/objtool/check.c           | 27 +--------------------------
 3 files changed, 40 insertions(+), 26 deletions(-)

(limited to 'tools')

diff --git a/tools/objtool/arch.h b/tools/objtool/arch.h
index b18c5f61d42d..4a84c3081b8e 100644
--- a/tools/objtool/arch.h
+++ b/tools/objtool/arch.h
@@ -88,4 +88,6 @@ unsigned long arch_dest_reloc_offset(int addend);
 
 const char *arch_nop_insn(int len);
 
+int arch_decode_hint_reg(struct instruction *insn, u8 sp_reg);
+
 #endif /* _ARCH_H */
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index 1967370440b3..cde9c36e40ae 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -15,6 +15,7 @@
 #include "../../elf.h"
 #include "../../arch.h"
 #include "../../warn.h"
+#include <asm/orc_types.h>
 
 static unsigned char op_to_cfi_reg[][2] = {
 	{CFI_AX, CFI_R8},
@@ -583,3 +584,39 @@ const char *arch_nop_insn(int len)
 
 	return nops[len-1];
 }
+
+int arch_decode_hint_reg(struct instruction *insn, u8 sp_reg)
+{
+	struct cfi_reg *cfa = &insn->cfi.cfa;
+
+	switch (sp_reg) {
+	case ORC_REG_UNDEFINED:
+		cfa->base = CFI_UNDEFINED;
+		break;
+	case ORC_REG_SP:
+		cfa->base = CFI_SP;
+		break;
+	case ORC_REG_BP:
+		cfa->base = CFI_BP;
+		break;
+	case ORC_REG_SP_INDIRECT:
+		cfa->base = CFI_SP_INDIRECT;
+		break;
+	case ORC_REG_R10:
+		cfa->base = CFI_R10;
+		break;
+	case ORC_REG_R13:
+		cfa->base = CFI_R13;
+		break;
+	case ORC_REG_DI:
+		cfa->base = CFI_DI;
+		break;
+	case ORC_REG_DX:
+		cfa->base = CFI_DX;
+		break;
+	default:
+		return -1;
+	}
+
+	return 0;
+}
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 95c6e0d31c0a..4e2f703b6a25 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1367,32 +1367,7 @@ static int read_unwind_hints(struct objtool_file *file)
 
 		insn->hint = true;
 
-		switch (hint->sp_reg) {
-		case ORC_REG_UNDEFINED:
-			cfa->base = CFI_UNDEFINED;
-			break;
-		case ORC_REG_SP:
-			cfa->base = CFI_SP;
-			break;
-		case ORC_REG_BP:
-			cfa->base = CFI_BP;
-			break;
-		case ORC_REG_SP_INDIRECT:
-			cfa->base = CFI_SP_INDIRECT;
-			break;
-		case ORC_REG_R10:
-			cfa->base = CFI_R10;
-			break;
-		case ORC_REG_R13:
-			cfa->base = CFI_R13;
-			break;
-		case ORC_REG_DI:
-			cfa->base = CFI_DI;
-			break;
-		case ORC_REG_DX:
-			cfa->base = CFI_DX;
-			break;
-		default:
+		if (arch_decode_hint_reg(insn, hint->sp_reg)) {
 			WARN_FUNC("unsupported unwind_hint sp base reg %d",
 				  insn->sec, insn->offset, hint->sp_reg);
 			return -1;
-- 
cgit v1.2.3


From f4f803984c3685f416a74e9e2fa7d39bdafbe02b Mon Sep 17 00:00:00 2001
From: Julien Thierry <jthierry@redhat.com>
Date: Tue, 15 Sep 2020 08:53:16 +0100
Subject: objtool: Remove useless tests before save_reg()

save_reg already checks that the register being saved does not already
have a saved state.

Remove redundant checks before processing a register storing operation.

Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/check.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

(limited to 'tools')

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 4e2f703b6a25..fd2edab8e672 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2030,7 +2030,7 @@ static int update_cfi_state(struct instruction *insn, struct cfi_state *cfi,
 				/* drap: push %rbp */
 				cfi->stack_size = 0;
 
-			} else if (regs[op->src.reg].base == CFI_UNDEFINED) {
+			} else {
 
 				/* drap: push %reg */
 				save_reg(cfi, op->src.reg, CFI_BP, -cfi->stack_size);
@@ -2059,9 +2059,7 @@ static int update_cfi_state(struct instruction *insn, struct cfi_state *cfi,
 
 				/* save drap offset so we know when to restore it */
 				cfi->drap_offset = op->dest.offset;
-			}
-
-			else if (regs[op->src.reg].base == CFI_UNDEFINED) {
+			} else {
 
 				/* drap: mov reg, disp(%rbp) */
 				save_reg(cfi, op->src.reg, CFI_BP, op->dest.offset);
-- 
cgit v1.2.3


From fb136219f0e2b417d84e67b2a3adc1f933997d04 Mon Sep 17 00:00:00 2001
From: Julien Thierry <jthierry@redhat.com>
Date: Tue, 15 Sep 2020 08:53:17 +0100
Subject: objtool: Ignore unreachable fake jumps

It is possible for alternative code to unconditionally jump out of the
alternative region. In such a case, if a fake jump is added at the end
of the alternative instructions, the fake jump will never be reached.
Since the fake jump is just a mean to make sure code validation does not
go beyond the set of alternatives, reaching it is not a requirement.

Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/check.c | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'tools')

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index fd2edab8e672..cd7c6698d316 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2648,6 +2648,9 @@ static bool ignore_unreachable_insn(struct instruction *insn)
 	    !strcmp(insn->sec->name, ".altinstr_aux"))
 		return true;
 
+	if (insn->type == INSN_JUMP_UNCONDITIONAL && insn->offset == FAKE_JUMP_OFFSET)
+		return true;
+
 	if (!insn->func)
 		return false;
 
-- 
cgit v1.2.3


From 2b232a22d8225df419a92ca69ddeeb4e5fe902f7 Mon Sep 17 00:00:00 2001
From: Julien Thierry <jthierry@redhat.com>
Date: Tue, 15 Sep 2020 08:53:18 +0100
Subject: objtool: Handle calling non-function symbols in other sections

Relocation for a call destination could point to a symbol that has
type STT_NOTYPE.

Lookup such a symbol when no function is available.

Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/check.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

(limited to 'tools')

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index cd7c6698d316..a4796e32bbd1 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -815,6 +815,17 @@ static void remove_insn_ops(struct instruction *insn)
 	}
 }
 
+static struct symbol *find_call_destination(struct section *sec, unsigned long offset)
+{
+	struct symbol *call_dest;
+
+	call_dest = find_func_by_offset(sec, offset);
+	if (!call_dest)
+		call_dest = find_symbol_by_offset(sec, offset);
+
+	return call_dest;
+}
+
 /*
  * Find the destination instructions for all calls.
  */
@@ -832,9 +843,7 @@ static int add_call_destinations(struct objtool_file *file)
 					       insn->offset, insn->len);
 		if (!reloc) {
 			dest_off = arch_jump_destination(insn);
-			insn->call_dest = find_func_by_offset(insn->sec, dest_off);
-			if (!insn->call_dest)
-				insn->call_dest = find_symbol_by_offset(insn->sec, dest_off);
+			insn->call_dest = find_call_destination(insn->sec, dest_off);
 
 			if (insn->ignore)
 				continue;
@@ -852,8 +861,8 @@ static int add_call_destinations(struct objtool_file *file)
 
 		} else if (reloc->sym->type == STT_SECTION) {
 			dest_off = arch_dest_reloc_offset(reloc->addend);
-			insn->call_dest = find_func_by_offset(reloc->sym->sec,
-							      dest_off);
+			insn->call_dest = find_call_destination(reloc->sym->sec,
+								dest_off);
 			if (!insn->call_dest) {
 				WARN_FUNC("can't find call dest symbol at %s+0x%lx",
 					  insn->sec, insn->offset,
-- 
cgit v1.2.3


From 14db1f0a93331d0958e90da522c429ff0890d2d6 Mon Sep 17 00:00:00 2001
From: Ilie Halip <ilie.halip@gmail.com>
Date: Sat, 19 Sep 2020 09:41:18 +0300
Subject: objtool: Ignore unreachable trap after call to noreturn functions

With CONFIG_UBSAN_TRAP enabled, the compiler may insert a trap
instruction after a call to a noreturn function. In this case, objtool
warns that the UD2 instruction is unreachable.

This is a behavior seen with Clang, from the oldest version capable of
building the mainline x64_64 kernel (9.0), to the latest experimental
version (12.0).

Objtool silences similar warnings (trap after dead end instructions), so
so expand that check to include dead end functions.

Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Rong Chen <rong.a.chen@intel.com>
Cc: Marco Elver <elver@google.com>
Cc: Philip Li <philip.li@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: kasan-dev@googlegroups.com
Cc: x86@kernel.org
Cc: clang-built-linux@googlegroups.com
BugLink: https://github.com/ClangBuiltLinux/linux/issues/1148
Link: https://lore.kernel.org/lkml/CAKwvOdmptEpi8fiOyWUo=AiZJiX+Z+VHJOM2buLPrWsMTwLnyw@mail.gmail.com
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Ilie Halip <ilie.halip@gmail.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/check.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

(limited to 'tools')

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index a4796e32bbd1..2df9f769412e 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2638,9 +2638,10 @@ static bool is_ubsan_insn(struct instruction *insn)
 			"__ubsan_handle_builtin_unreachable"));
 }
 
-static bool ignore_unreachable_insn(struct instruction *insn)
+static bool ignore_unreachable_insn(struct objtool_file *file, struct instruction *insn)
 {
 	int i;
+	struct instruction *prev_insn;
 
 	if (insn->ignore || insn->type == INSN_NOP)
 		return true;
@@ -2668,8 +2669,11 @@ static bool ignore_unreachable_insn(struct instruction *insn)
 	 * __builtin_unreachable().  The BUG() macro has an unreachable() after
 	 * the UD2, which causes GCC's undefined trap logic to emit another UD2
 	 * (or occasionally a JMP to UD2).
+	 *
+	 * It may also insert a UD2 after calling a __noreturn function.
 	 */
-	if (list_prev_entry(insn, list)->dead_end &&
+	prev_insn = list_prev_entry(insn, list);
+	if ((prev_insn->dead_end || dead_end_function(file, prev_insn->call_dest)) &&
 	    (insn->type == INSN_BUG ||
 	     (insn->type == INSN_JUMP_UNCONDITIONAL &&
 	      insn->jump_dest && insn->jump_dest->type == INSN_BUG)))
@@ -2796,7 +2800,7 @@ static int validate_reachable_instructions(struct objtool_file *file)
 		return 0;
 
 	for_each_insn(file, insn) {
-		if (insn->visited || ignore_unreachable_insn(insn))
+		if (insn->visited || ignore_unreachable_insn(file, insn))
 			continue;
 
 		WARN_FUNC("unreachable instruction", insn->sec, insn->offset);
-- 
cgit v1.2.3


From b0b8e56b82c06b3bb6e5fb66d0e9c9c3fd3ce555 Mon Sep 17 00:00:00 2001
From: Jann Horn <jannh@google.com>
Date: Tue, 29 Sep 2020 00:49:16 +0200
Subject: objtool: Permit __kasan_check_{read,write} under UACCESS
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Building linux-next with JUMP_LABEL=n and KASAN=y, I got this objtool
warning:

arch/x86/lib/copy_mc.o: warning: objtool: copy_mc_to_user()+0x22: call to
__kasan_check_read() with UACCESS enabled

What happens here is that copy_mc_to_user() branches on a static key in a
UACCESS region:

        __uaccess_begin();
        if (static_branch_unlikely(&copy_mc_fragile_key))
                ret = copy_mc_fragile(to, from, len);
        ret = copy_mc_generic(to, from, len);
        __uaccess_end();

and the !CONFIG_JUMP_LABEL version of static_branch_unlikely() uses
static_key_enabled(), which uses static_key_count(), which uses
atomic_read(), which calls instrument_atomic_read(), which uses
kasan_check_read(), which is __kasan_check_read().

Let's permit these KASAN helpers in UACCESS regions - static keys should
probably work under UACCESS, I think.

PeterZ adds:

  It's not a matter of permitting, it's a matter of being safe and
  correct. In this case it is, because it's a thin wrapper around
  check_memory_region() which was already marked safe.

  check_memory_region() is correct because the only thing it ends up
  calling is kasa_report() and that is also marked safe because that is
  annotated with user_access_save/restore() before it does anything else.

  On top of that, all of KASAN is noinstr, so nothing in here will end up
  in tracing and/or call schedule() before the user_access_save().

Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/check.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'tools')

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 2df9f769412e..3d14134c4e97 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -583,6 +583,8 @@ static const char *uaccess_safe_builtin[] = {
 	"__asan_store4_noabort",
 	"__asan_store8_noabort",
 	"__asan_store16_noabort",
+	"__kasan_check_read",
+	"__kasan_check_write",
 	/* KASAN in-line */
 	"__asan_report_load_n_noabort",
 	"__asan_report_load1_noabort",
-- 
cgit v1.2.3


From 2486baae2cf6df73554144d0a4e40ae8809b54d4 Mon Sep 17 00:00:00 2001
From: Vasily Gorbik <gor@linux.ibm.com>
Date: Mon, 5 Oct 2020 17:50:28 +0200
Subject: objtool: Allow nested externs to enable BUILD_BUG()

Currently BUILD_BUG() macro is expanded to smth like the following:
   do {
           extern void __compiletime_assert_0(void)
                   __attribute__((error("BUILD_BUG failed")));
           if (!(!(1)))
                   __compiletime_assert_0();
   } while (0);

If used in a function body this obviously would produce build errors
with -Wnested-externs and -Werror.

Build objtool with -Wno-nested-externs to enable BUILD_BUG() usage.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'tools')

diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index 33d1e3ca8efd..4ea9a833dde7 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -37,7 +37,7 @@ INCLUDES := -I$(srctree)/tools/include \
 	    -I$(srctree)/tools/arch/$(HOSTARCH)/include/uapi \
 	    -I$(srctree)/tools/arch/$(SRCARCH)/include	\
 	    -I$(srctree)/tools/objtool/arch/$(SRCARCH)/include
-WARNINGS := $(EXTRA_WARNINGS) -Wno-switch-default -Wno-switch-enum -Wno-packed
+WARNINGS := $(EXTRA_WARNINGS) -Wno-switch-default -Wno-switch-enum -Wno-packed -Wno-nested-externs
 CFLAGS   := -Werror $(WARNINGS) $(KBUILD_HOSTCFLAGS) -g $(INCLUDES) $(LIBELF_FLAGS)
 LDFLAGS  += $(LIBELF_LIBS) $(LIBSUBCMD) $(KBUILD_HOSTLDFLAGS)
 
-- 
cgit v1.2.3


From ab0a40ea88204e1291b56da8128e2845fec8ee88 Mon Sep 17 00:00:00 2001
From: Vasily Gorbik <gor@linux.ibm.com>
Date: Fri, 9 Oct 2020 14:25:23 +0200
Subject: perf build: Allow nested externs to enable BUILD_BUG() usage

Currently the BUILD_BUG() macro is expanded to the following:

   do {
           extern void __compiletime_assert_0(void)
                   __attribute__((error("BUILD_BUG failed")));
           if (!(!(1)))
                   __compiletime_assert_0();
   } while (0);

If used in a function body this would obviously produce build errors
with -Wnested-externs and -Werror.

To enable BUILD_BUG() usage in tools/arch/x86/lib/insn.c which perf
includes in intel-pt-decoder, build perf without -Wnested-externs.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Tested-by: Stephen Rothwell <sfr@canb.auug.org.au> # build tested
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/patch-1.thread-251403.git-2514037e9477.your-ad-here.call-01602244460-ext-7088@work.hours
---
 tools/perf/Makefile.config | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'tools')

diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 190be4fa5c21..8137a6046a47 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -16,7 +16,7 @@ $(shell printf "" > $(OUTPUT).config-detected)
 detected     = $(shell echo "$(1)=y"       >> $(OUTPUT).config-detected)
 detected_var = $(shell echo "$(1)=$($(1))" >> $(OUTPUT).config-detected)
 
-CFLAGS := $(EXTRA_CFLAGS) $(EXTRA_WARNINGS)
+CFLAGS := $(EXTRA_CFLAGS) $(filter-out -Wnested-externs,$(EXTRA_WARNINGS))
 
 include $(srctree)/tools/scripts/Makefile.arch
 
-- 
cgit v1.2.3