Merge tag 'linux-kselftest-5.2-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull more kselftest updates from Shuah Khan:

- kselftest framework bpf build/test workflow regression fix

- Fix to kselftest install to use default install path

- Fix to kselftest KBUILD_OUTPUT builds to not clutter main
KBUILD_OUTPUT directory with selftest objects

- .gitignore fixes (Kelsey Skunberg)

- rseq selftests updates (Mathieu Desnoyers and Martin Schwidefsky)

They change the per-architecture pre-abort signatures to ensure those
are valid trap instructions.

The way exit points are presented to debuggers is enhanced, ensuring
all exit points are present, so debuggers don't have to disassemble
rseq critical section to properly skip over them.

Discussions with the glibc community is reaching a consensus of
exposing a __rseq_handled symbol from glibc to coexist with rseq
early adopters. Update the rseq selftest code to expose and use this
symbol.

Support for compiling asm goto with clang is added with the
"-no-integrated-as" compiler switch, similarly to the top level
kernel Makefile.

- kselftest Makefile test run output refactoring and making test output
TAP13 compliant from Kees Cook:

This re-factors the selftest Makefiles to extract the test running
logic to be reused between "run_tests" and "emit_tests", while also
fixing up the test output to be TAP version 13 compliant:
- added "plan" line
- fixed result line syntax
- moved all test output to be "# "-prefixed as TAP "diagnostic"
lines

The prefixing code includes a fallback mode for limited execution
environments.

Additionally, the plan lines are fixed for all callers of
kselftest.h.

* tag 'linux-kselftest-5.2-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (25 commits)
selftests: avoid KBUILD_OUTPUT dir cluttering with selftest objects
selftests: drivers: Create .gitignore to include /dma-buf/udmabuf
selftests: pidfd: Create .gitignore to include pidfd_test
selftests: fix bpf build/test workflow regression when KBUILD_OUTPUT is set
selftests: fix install target to use default install path
rseq/selftests: add -no-integrated-as for clang
rseq/selftests: mips: use break instruction for RSEQ_SIG
rseq/selftests: powerpc code signature: generate valid instructions
rseq/selftests: aarch64 code signature: handle big-endian environment
rseq/selftests: arm: use udf instruction for RSEQ_SIG
rseq/selftests: s390: use trap4 for RSEQ_SIG
rseq/selftests: x86: use ud1 instruction as RSEQ_SIG opcode
rseq/selftests: s390: use jg instruction for jumps outside of the asm
rseq/selftests: Use __rseq_handled symbol to coexist with glibc
rseq/selftests: Introduce __rseq_cs_ptr_array, rename __rseq_table to __rseq_cs
rseq/selftests: Add __rseq_exit_point_array section for debuggers
rseq/selftests: x86: Work-around bogus gcc-8 optimisation
selftests: Add test plan API to kselftest.h and adjust callers
selftests: Remove KSFT_TAP_LEVEL
selftests: Move test output to diagnostic lines
...

tools/testing/selftests/.gitignore

···
-kselftest
 gpiogpio-event-mon
 gpiogpio-hammer
 gpioinclude/

tools/testing/selftests/Makefile

···
 override MAKEFLAGS =
 endif
 
+# Append kselftest to KBUILD_OUTPUT to avoid cluttering
+# KBUILD_OUTPUT with selftest objects and headers installed
+# by selftests Makefile or lib.mk.
 ifneq ($(KBUILD_SRC),)
 override LDFLAGS =
 endif
···
 	BUILD := $(O)
 else
 	ifneq ($(KBUILD_OUTPUT),)
-		BUILD := $(KBUILD_OUTPUT)
+		BUILD := $(KBUILD_OUTPUT)/kselftest
 	else
 		BUILD := $(shell pwd)
 		DEFAULT_INSTALL_HDR_PATH := 1
 	endif
 endif
-
-# KSFT_TAP_LEVEL is used from KSFT framework to prevent nested TAP header
-# printing from tests. Applicable to run_tests case where run_tests adds
-# TAP header prior running tests and when a test program invokes another
-# with system() call. Export it here to cover override RUN_TESTS defines.
-export KSFT_TAP_LEVEL=`echo 1`
 
 # Prepare for headers install
 top_srcdir ?= ../../..
···
 run_pstore_crash:
 	make -C pstore run_crash
 
-INSTALL_PATH ?= install
+# Use $BUILD as the default install root. $BUILD points to the
+# right output location for the following cases:
+# 1. output_dir=kernel_src
+# 2. a separate output directory is specified using O= KBUILD_OUTPUT
+# 3. a separate output directory is specified using KBUILD_OUTPUT
+#
+INSTALL_PATH ?= $(BUILD)/install
 INSTALL_PATH := $(abspath $(INSTALL_PATH))
 ALL_SCRIPT := $(INSTALL_PATH)/run_kselftest.sh
 
-install:
+install: all
 ifdef INSTALL_PATH
 	@# Ask all targets to install their files
-	mkdir -p $(INSTALL_PATH)
+	mkdir -p $(INSTALL_PATH)/kselftest
+	install -m 744 kselftest/runner.sh $(INSTALL_PATH)/kselftest/
+	install -m 744 kselftest/prefix.pl $(INSTALL_PATH)/kselftest/
 	@for TARGET in $(TARGETS); do \
 		BUILD_TARGET=$$BUILD/$$TARGET;	\
 		make OUTPUT=$$BUILD_TARGET -C $$TARGET INSTALL_PATH=$(INSTALL_PATH)/$$TARGET install; \
···
 	echo "#!/bin/sh" > $(ALL_SCRIPT)
 	echo "BASE_DIR=\$$(realpath \$$(dirname \$$0))" >> $(ALL_SCRIPT)
 	echo "cd \$$BASE_DIR" >> $(ALL_SCRIPT)
+	echo ". ./kselftest/runner.sh" >> $(ALL_SCRIPT)
 	echo "ROOT=\$$PWD" >> $(ALL_SCRIPT)
 	echo "if [ \"\$$1\" = \"--summary\" ]; then" >> $(ALL_SCRIPT)
-	echo "  OUTPUT=\$$BASE_DIR/output.log" >> $(ALL_SCRIPT)
-	echo "  cat /dev/null > \$$OUTPUT" >> $(ALL_SCRIPT)
-	echo "else" >> $(ALL_SCRIPT)
-	echo "  OUTPUT=/dev/stdout" >> $(ALL_SCRIPT)
+	echo "  logfile=\$$BASE_DIR/output.log" >> $(ALL_SCRIPT)
+	echo "  cat /dev/null > \$$logfile" >> $(ALL_SCRIPT)
 	echo "fi" >> $(ALL_SCRIPT)
-	echo "export KSFT_TAP_LEVEL=1" >> $(ALL_SCRIPT)
-	echo "export skip=4" >> $(ALL_SCRIPT)
 
 	for TARGET in $(TARGETS); do \
 		BUILD_TARGET=$$BUILD/$$TARGET;	\
-		echo "echo ; echo TAP version 13" >> $(ALL_SCRIPT);	\
-		echo "echo Running tests in $$TARGET" >> $(ALL_SCRIPT); \
-		echo "echo ========================================" >> $(ALL_SCRIPT); \
 		echo "[ -w /dev/kmsg ] && echo \"kselftest: Running tests in $$TARGET\" >> /dev/kmsg" >> $(ALL_SCRIPT); \
 		echo "cd $$TARGET" >> $(ALL_SCRIPT); \
+		echo -n "run_many" >> $(ALL_SCRIPT); \
 		make -s --no-print-directory OUTPUT=$$BUILD_TARGET -C $$TARGET emit_tests >> $(ALL_SCRIPT); \
+		echo "" >> $(ALL_SCRIPT);	    \
 		echo "cd \$$ROOT" >> $(ALL_SCRIPT); \
 	done;
 

tools/testing/selftests/breakpoints/breakpoint_test.c

···
 
 #include "../kselftest.h"
 
+#define COUNT_ISN_BPS	4
+#define COUNT_WPS	4
 
 /* Breakpoint access modes */
 enum {
···
 			if (!local && !global)
 				continue;
 
-			for (i = 0; i < 4; i++) {
+			for (i = 0; i < COUNT_ISN_BPS; i++) {
 				dummy_funcs[i]();
 				check_trapped();
 			}
···
 {
 	int i;
 
-	for (i = 0; i < 4; i++) {
+	for (i = 0; i < COUNT_ISN_BPS; i++) {
 		set_breakpoint_addr(dummy_funcs[i], i);
 		toggle_breakpoint(i, BP_X, 1, local, global, 1);
 		ptrace(PTRACE_CONT, child_pid, NULL, 0);
···
 	else
 		mode_str = "read";
 
-	for (i = 0; i < 4; i++) {
+	for (i = 0; i < COUNT_WPS; i++) {
 		set_breakpoint_addr(&dummy_var[i], i);
 		toggle_breakpoint(i, mode, len, local, global, 1);
 		ptrace(PTRACE_CONT, child_pid, NULL, 0);
···
 static void launch_tests(void)
 {
 	char buf[1024];
+	unsigned int tests = 0;
 	int len, local, global, i;
+
+	tests += 3 * COUNT_ISN_BPS;
+	tests += sizeof(long) / 2 * 3 * COUNT_WPS;
+	tests += sizeof(long) / 2 * 3 * COUNT_WPS;
+	tests += 2;
+	ksft_set_plan(tests);
 
 	/* Instruction breakpoints */
 	for (local = 0; local < 2; local++) {

tools/testing/selftests/breakpoints/breakpoint_test_arm64.c

···
 	return false;
 }
 
-static bool run_test(int wr_size, int wp_size, int wr, int wp)
+static bool arun_test(int wr_size, int wp_size, int wr, int wp)
 {
 	int status;
 	siginfo_t siginfo;
···
 	bool result;
 
 	ksft_print_header();
+	ksft_set_plan(213);
 
 	act.sa_handler = sigalrm;
 	sigemptyset(&act.sa_mask);

tools/testing/selftests/breakpoints/step_after_suspend_test.c

···
 	int opt;
 	bool do_suspend = true;
 	bool succeeded = true;
+	unsigned int tests = 0;
 	cpu_set_t available_cpus;
 	int err;
 	int cpu;
···
 			return -1;
 		}
 	}
+
+	for (cpu = 0; cpu < CPU_SETSIZE; cpu++) {
+		if (!CPU_ISSET(cpu, &available_cpus))
+			continue;
+		tests++;
+	}
+	ksft_set_plan(tests);
 
 	if (do_suspend)
 		suspend();

tools/testing/selftests/capabilities/test_execve.c

···
 {
 	char *tmp1, *tmp2, *our_path;
 
-	ksft_print_header();
-
 	/* Find our path */
 	tmp1 = strdup(argv[0]);
 	if (!tmp1)
···
 	mpid = getpid();
 
 	if (fork_wait()) {
+		ksft_print_header();
+		ksft_set_plan(12);
 		ksft_print_msg("[RUN]\t+++ Tests with uid == 0 +++\n");
 		return do_tests(0, our_path);
 	}
···
 	ksft_print_msg("==================================================\n");
 
 	if (fork_wait()) {
+		ksft_print_header();
+		ksft_set_plan(9);
 		ksft_print_msg("[RUN]\t+++ Tests with uid != 0 +++\n");
 		return do_tests(1, our_path);
 	}

tools/testing/selftests/drivers/.gitignore

···
+/dma-buf/udmabuf

tools/testing/selftests/futex/functional/futex_requeue_pi.c

···
 	}
 
 	ksft_print_header();
+	ksft_set_plan(1);
 	ksft_print_msg("%s: Test requeue functionality\n", basename(argv[0]));
 	ksft_print_msg(
 		"\tArguments: broadcast=%d locked=%d owner=%d timeout=%ldns\n",

tools/testing/selftests/futex/functional/futex_requeue_pi_mismatched_ops.c

···
 	}
 
 	ksft_print_header();
+	ksft_set_plan(1);
 	ksft_print_msg("%s: Detect mismatched requeue_pi operations\n",
 	       basename(argv[0]));
 

tools/testing/selftests/futex/functional/futex_requeue_pi_signal_restart.c

···
 	}
 
 	ksft_print_header();
+	ksft_set_plan(1);
 	ksft_print_msg("%s: Test signal handling during requeue_pi\n",
 	       basename(argv[0]));
 	ksft_print_msg("\tArguments: <none>\n");

tools/testing/selftests/futex/functional/futex_wait_private_mapped_file.c

···
 	}
 
 	ksft_print_header();
+	ksft_set_plan(1);
 	ksft_print_msg(
 		"%s: Test the futex value of private file mappings in FUTEX_WAIT\n",
 		basename(argv[0]));

tools/testing/selftests/futex/functional/futex_wait_timeout.c

···
 	}
 
 	ksft_print_header();
+	ksft_set_plan(1);
 	ksft_print_msg("%s: Block on a futex and wait for timeout\n",
 	       basename(argv[0]));
 	ksft_print_msg("\tArguments: timeout=%ldns\n", timeout_ns);

tools/testing/selftests/futex/functional/futex_wait_uninitialized_heap.c

···
 	}
 
 	ksft_print_header();
+	ksft_set_plan(1);
 	ksft_print_msg("%s: Test the uninitialized futex value in FUTEX_WAIT\n",
 	       basename(argv[0]));
 

tools/testing/selftests/futex/functional/futex_wait_wouldblock.c

···
 	}
 
 	ksft_print_header();
+	ksft_set_plan(1);
 	ksft_print_msg("%s: Test the unexpected futex value in FUTEX_WAIT\n",
 	       basename(argv[0]));
 

tools/testing/selftests/kselftest.h

···
 };
 
 static struct ksft_count ksft_cnt;
+static unsigned int ksft_plan;
 
 static inline int ksft_test_num(void)
 {
···
 		printf("TAP version 13\n");
 }
 
+static inline void ksft_set_plan(unsigned int plan)
+{
+	ksft_plan = plan;
+	printf("1..%d\n", ksft_plan);
+}
+
 static inline void ksft_print_cnts(void)
 {
-	printf("Pass %d Fail %d Xfail %d Xpass %d Skip %d Error %d\n",
+	if (ksft_plan != ksft_test_num())
+		printf("# Planned tests != run tests (%u != %u)\n",
+			ksft_plan, ksft_test_num());
+	printf("# Pass %d Fail %d Xfail %d Xpass %d Skip %d Error %d\n",
 		ksft_cnt.ksft_pass, ksft_cnt.ksft_fail,
 		ksft_cnt.ksft_xfail, ksft_cnt.ksft_xpass,
 		ksft_cnt.ksft_xskip, ksft_cnt.ksft_error);
-	printf("1..%d\n", ksft_test_num());
 }
 
 static inline void ksft_print_msg(const char *msg, ...)
···
 	ksft_cnt.ksft_xskip++;
 
 	va_start(args, msg);
-	printf("ok %d # skip ", ksft_test_num());
+	printf("not ok %d # SKIP ", ksft_test_num());
 	vprintf(msg, args);
 	va_end(args);
 }
···
 		va_list args;
 
 		va_start(args, msg);
-		printf("1..%d # Skipped: ", ksft_test_num());
+		printf("not ok %d # SKIP ", 1 + ksft_test_num());
 		vprintf(msg, args);
 		va_end(args);
 	} else {

tools/testing/selftests/kselftest/prefix.pl

···
+#!/usr/bin/perl
+# SPDX-License-Identifier: GPL-2.0
+# Prefix all lines with "# ", unbuffered. Command being piped in may need
+# to have unbuffering forced with "stdbuf -i0 -o0 -e0 $cmd".
+use strict;
+
+binmode STDIN;
+binmode STDOUT;
+
+STDOUT->autoflush(1);
+
+my $needed = 1;
+while (1) {
+	my $char;
+	my $bytes = sysread(STDIN, $char, 1);
+	exit 0 if ($bytes == 0);
+	if ($needed) {
+		print "# ";
+		$needed = 0;
+	}
+	print $char;
+	$needed = 1 if ($char eq "\n");
+}

tools/testing/selftests/kselftest/runner.sh

···
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Runs a set of tests in a given subdirectory.
+export skip_rc=4
+export logfile=/dev/stdout
+export per_test_logging=
+
+# There isn't a shell-agnostic way to find the path of a sourced file,
+# so we must rely on BASE_DIR being set to find other tools.
+if [ -z "$BASE_DIR" ]; then
+	echo "Error: BASE_DIR must be set before sourcing." >&2
+	exit 1
+fi
+
+# If Perl is unavailable, we must fall back to line-at-a-time prefixing
+# with sed instead of unbuffered output.
+tap_prefix()
+{
+	if [ ! -x /usr/bin/perl ]; then
+		sed -e 's/^/# /'
+	else
+		"$BASE_DIR"/kselftest/prefix.pl
+	fi
+}
+
+# If stdbuf is unavailable, we must fall back to line-at-a-time piping.
+tap_unbuffer()
+{
+	if ! which stdbuf >/dev/null ; then
+		"$@"
+	else
+		stdbuf -i0 -o0 -e0 "$@"
+	fi
+}
+
+run_one()
+{
+	DIR="$1"
+	TEST="$2"
+	NUM="$3"
+
+	BASENAME_TEST=$(basename $TEST)
+
+	TEST_HDR_MSG="selftests: $DIR: $BASENAME_TEST"
+	echo "# $TEST_HDR_MSG"
+	if [ ! -x "$TEST" ]; then
+		echo -n "# Warning: file $TEST is "
+		if [ ! -e "$TEST" ]; then
+			echo "missing!"
+		else
+			echo "not executable, correct this."
+		fi
+		echo "not ok $test_num $TEST_HDR_MSG"
+	else
+		cd `dirname $TEST` > /dev/null
+		(((((tap_unbuffer ./$BASENAME_TEST 2>&1; echo $? >&3) |
+			tap_prefix >&4) 3>&1) |
+			(read xs; exit $xs)) 4>>"$logfile" &&
+		echo "ok $test_num $TEST_HDR_MSG") ||
+		(if [ $? -eq $skip_rc ]; then	\
+			echo "not ok $test_num $TEST_HDR_MSG # SKIP"
+		else
+			echo "not ok $test_num $TEST_HDR_MSG"
+		fi)
+		cd - >/dev/null
+	fi
+}
+
+run_many()
+{
+	echo "TAP version 13"
+	DIR=$(basename "$PWD")
+	test_num=0
+	total=$(echo "$@" | wc -w)
+	echo "1..$total"
+	for TEST in "$@"; do
+		BASENAME_TEST=$(basename $TEST)
+		test_num=$(( test_num + 1 ))
+		if [ -n "$per_test_logging" ]; then
+			logfile="/tmp/$BASENAME_TEST"
+			cat /dev/null > "$logfile"
+		fi
+		run_one "$DIR" "$TEST" "$test_num"
+	done
+}

tools/testing/selftests/lib.mk

···
 CC := $(CROSS_COMPILE)gcc
 
 ifeq (0,$(MAKELEVEL))
-    ifneq ($(O),)
-	OUTPUT := $(O)
-    else
-	ifneq ($(KBUILD_OUTPUT),)
-		OUTPUT := $(KBUILD_OUTPUT)
-	else
-		OUTPUT := $(shell pwd)
-		DEFAULT_INSTALL_HDR_PATH := 1
-	endif
+    ifeq ($(OUTPUT),)
+	OUTPUT := $(shell pwd)
+	DEFAULT_INSTALL_HDR_PATH := 1
     endif
 endif
+selfdir = $(realpath $(dir $(filter %/lib.mk,$(MAKEFILE_LIST))))
 
 # The following are built by lib.mk common compile rules.
 # TEST_CUSTOM_PROGS should be used by tests that require
···
 endif
 
 .ONESHELL:
-define RUN_TEST_PRINT_RESULT
-	TEST_HDR_MSG="selftests: "`basename $$PWD`:" $$BASENAME_TEST";	\
-	echo $$TEST_HDR_MSG;					\
-	echo "========================================";	\
-	if [ ! -x $$TEST ]; then	\
-		echo "$$TEST_HDR_MSG: Warning: file $$BASENAME_TEST is not executable, correct this.";\
-		echo "not ok 1..$$test_num $$TEST_HDR_MSG [FAIL]"; \
-	else					\
-		cd `dirname $$TEST` > /dev/null; \
-		if [ "X$(summary)" != "X" ]; then	\
-			(./$$BASENAME_TEST > /tmp/$$BASENAME_TEST 2>&1 && \
-			echo "ok 1..$$test_num $$TEST_HDR_MSG [PASS]") || \
-			(if [ $$? -eq $$skip ]; then	\
-				echo "not ok 1..$$test_num $$TEST_HDR_MSG [SKIP]";				\
-			else echo "not ok 1..$$test_num $$TEST_HDR_MSG [FAIL]";					\
-			fi;)			\
-		else				\
-			(./$$BASENAME_TEST &&	\
-			echo "ok 1..$$test_num $$TEST_HDR_MSG [PASS]") ||						\
-			(if [ $$? -eq $$skip ]; then \
-				echo "not ok 1..$$test_num $$TEST_HDR_MSG [SKIP]"; \
-			else echo "not ok 1..$$test_num $$TEST_HDR_MSG [FAIL]";				\
-			fi;)		\
-		fi;				\
-		cd - > /dev/null;		\
-	fi;
-endef
-
 define RUN_TESTS
-	@export KSFT_TAP_LEVEL=`echo 1`;		\
-	test_num=`echo 0`;				\
-	skip=`echo 4`;					\
-	echo "TAP version 13";				\
-	for TEST in $(1); do				\
-		BASENAME_TEST=`basename $$TEST`;	\
-		test_num=`echo $$test_num+1 | bc`;	\
-		$(call RUN_TEST_PRINT_RESULT,$(TEST),$(BASENAME_TEST),$(test_num),$(skip))						\
-	done;
+	@BASE_DIR="$(selfdir)";			\
+	. $(selfdir)/kselftest/runner.sh;	\
+	if [ "X$(summary)" != "X" ]; then       \
+		per_test_logging=1;		\
+	fi;                                     \
+	run_many $(1)
 endef
 
 run_tests: all
···
 	$(error Error: set INSTALL_PATH to use install)
 endif
 
-define EMIT_TESTS
-	@test_num=`echo 0`;				\
+emit_tests:
 	for TEST in $(TEST_GEN_PROGS) $(TEST_CUSTOM_PROGS) $(TEST_PROGS); do \
 		BASENAME_TEST=`basename $$TEST`;	\
-		test_num=`echo $$test_num+1 | bc`;	\
-		TEST_HDR_MSG="selftests: "`basename $$PWD`:" $$BASENAME_TEST";	\
-		echo "echo $$TEST_HDR_MSG";	\
-		if [ ! -x $$TEST ]; then	\
-			echo "echo \"$$TEST_HDR_MSG: Warning: file $$BASENAME_TEST is not executable, correct this.\"";		\
-			echo "echo \"not ok 1..$$test_num $$TEST_HDR_MSG [FAIL]\""; \
-		else
-			echo "(./$$BASENAME_TEST >> \$$OUTPUT 2>&1 && echo \"ok 1..$$test_num $$TEST_HDR_MSG [PASS]\") || (if [ \$$? -eq \$$skip ]; then echo \"not ok 1..$$test_num $$TEST_HDR_MSG [SKIP]\"; else echo \"not ok 1..$$test_num $$TEST_HDR_MSG [FAIL]\"; fi;)"; \
-		fi;		\
-	done;
-endef
-
-emit_tests:
-	$(EMIT_TESTS)
+		echo "	\\";				\
+		echo -n "	\"$$BASENAME_TEST\"";	\
+	done;						\
 
 # define if isn't already. It is undefined in make O= case.
 ifeq ($(RM),)

tools/testing/selftests/membarrier/membarrier_test.c

···
 int main(int argc, char **argv)
 {
 	ksft_print_header();
+	ksft_set_plan(13);
 
 	test_membarrier_query();
 	test_membarrier();

tools/testing/selftests/pidfd/.gitignore

···
+pidfd_test

tools/testing/selftests/pidfd/pidfd_test.c

···
 int main(int argc, char **argv)
 {
 	ksft_print_header();
+	ksft_set_plan(4);
 
 	test_pidfd_send_signal_syscall_support();
 	test_pidfd_send_signal_simple_success();

tools/testing/selftests/rseq/Makefile

···
 # SPDX-License-Identifier: GPL-2.0+ OR MIT
-CFLAGS += -O2 -Wall -g -I./ -I../../../../usr/include/ -L./ -Wl,-rpath=./
+
+ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep clang),)
+CLANG_FLAGS += -no-integrated-as
+endif
+
+CFLAGS += -O2 -Wall -g -I./ -I../../../../usr/include/ -L./ -Wl,-rpath=./ \
+	  $(CLANG_FLAGS)
 LDLIBS += -lpthread
 
 # Own dependencies because we only want to build against 1st prerequisite, but

tools/testing/selftests/rseq/rseq-arm.h

···
  * (C) Copyright 2016-2018 - Mathieu Desnoyers <[e-mail]>
  */
 
-#define RSEQ_SIG	0x53053053
+/*
+ * RSEQ_SIG uses the udf A32 instruction with an uncommon immediate operand
+ * value 0x5de3. This traps if user-space reaches this instruction by mistake,
+ * and the uncommon operand ensures the kernel does not move the instruction
+ * pointer to attacker-controlled code on rseq abort.
+ *
+ * The instruction pattern in the A32 instruction set is:
+ *
+ * e7f5def3    udf    #24035    ; 0x5de3
+ *
+ * This translates to the following instruction pattern in the T16 instruction
+ * set:
+ *
+ * little endian:
+ * def3        udf    #243      ; 0xf3
+ * e7f5        b.n    <7f5>
+ *
+ * pre-ARMv6 big endian code:
+ * e7f5        b.n    <7f5>
+ * def3        udf    #243      ; 0xf3
+ *
+ * ARMv6+ -mbig-endian generates mixed endianness code vs data: little-endian
+ * code and big-endian data. Ensure the RSEQ_SIG data signature matches code
+ * endianness. Prior to ARMv6, -mbig-endian generates big-endian code and data
+ * (which match), so there is no need to reverse the endianness of the data
+ * representation of the signature. However, the choice between BE32 and BE8
+ * is done by the linker, so we cannot know whether code and data endianness
+ * will be mixed before the linker is invoked.
+ */
+
+#define RSEQ_SIG_CODE	0xe7f5def3
+
+#ifndef __ASSEMBLER__
+
+#define RSEQ_SIG_DATA							\
+	({								\
+		int sig;						\
+		asm volatile ("b 2f\n\t"				\
+			      "1: .inst " __rseq_str(RSEQ_SIG_CODE) "\n\t" \
+			      "2:\n\t"					\
+			      "ldr %[sig], 1b\n\t"			\
+			      : [sig] "=r" (sig));			\
+		sig;							\
+	})
+
+#define RSEQ_SIG	RSEQ_SIG_DATA
+
+#endif
 
 #define rseq_smp_mb()	__asm__ __volatile__ ("dmb" ::: "memory", "cc")
 #define rseq_smp_rmb()	__asm__ __volatile__ ("dmb" ::: "memory", "cc")
···
 #include "rseq-skip.h"
 #else /* !RSEQ_SKIP_FASTPATH */
 
-#define __RSEQ_ASM_DEFINE_TABLE(version, flags,	start_ip,		\
+#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, start_ip,	\
 				post_commit_offset, abort_ip)		\
-		".pushsection __rseq_table, \"aw\"\n\t"			\
+		".pushsection __rseq_cs, \"aw\"\n\t"			\
 		".balign 32\n\t"					\
+		__rseq_str(label) ":\n\t"					\
 		".word " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
 		".word " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) ", 0x0\n\t" \
+		".popsection\n\t"					\
+		".pushsection __rseq_cs_ptr_array, \"aw\"\n\t"		\
+		".word " __rseq_str(label) "b, 0x0\n\t"			\
 		".popsection\n\t"
 
-#define RSEQ_ASM_DEFINE_TABLE(start_ip, post_commit_ip, abort_ip)	\
-	__RSEQ_ASM_DEFINE_TABLE(0x0, 0x0, start_ip,			\
+#define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
+	__RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip,		\
 				(post_commit_ip - start_ip), abort_ip)
+
+/*
+ * Exit points of a rseq critical section consist of all instructions outside
+ * of the critical section where a critical section can either branch to or
+ * reach through the normal course of its execution. The abort IP and the
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
+ * useful to assist debuggers stepping over the critical section.
+ */
+#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip)			\
+		".pushsection __rseq_exit_point_array, \"aw\"\n\t"	\
+		".word " __rseq_str(start_ip) ", 0x0, " __rseq_str(exit_ip) ", 0x0\n\t" \
+		".popsection\n\t"
 
 #define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs)		\
 		RSEQ_INJECT_ASM(1)					\
···
 		__rseq_str(table_label) ":\n\t"				\
 		".word " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
 		".word " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) ", 0x0\n\t" \
-		".word " __rseq_str(RSEQ_SIG) "\n\t"			\
+		".arm\n\t"						\
+		".inst " __rseq_str(RSEQ_SIG_CODE) "\n\t"		\
 		__rseq_str(label) ":\n\t"				\
 		teardown						\
 		"b %l[" __rseq_str(abort_label) "]\n\t"
···
 
 	rseq_workaround_gcc_asm_size_guess();
 	__asm__ __volatile__ goto (
-		RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
···
 
 	rseq_workaround_gcc_asm_size_guess();
 	__asm__ __volatile__ goto (
-		RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
···
 
 	rseq_workaround_gcc_asm_size_guess();
 	__asm__ __volatile__ goto (
-		RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
···
 
 	rseq_workaround_gcc_asm_size_guess();
 	__asm__ __volatile__ goto (
-		RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
···
 
 	rseq_workaround_gcc_asm_size_guess();
 	__asm__ __volatile__ goto (
-		RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
···
 
 	rseq_workaround_gcc_asm_size_guess();
 	__asm__ __volatile__ goto (
-		RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error3])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
···
 
 	rseq_workaround_gcc_asm_size_guess();
 	__asm__ __volatile__ goto (
-		RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		"str %[src], %[rseq_scratch0]\n\t"
 		"str %[dst], %[rseq_scratch1]\n\t"
 		"str %[len], %[rseq_scratch2]\n\t"
···
 
 	rseq_workaround_gcc_asm_size_guess();
 	__asm__ __volatile__ goto (
-		RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		"str %[src], %[rseq_scratch0]\n\t"
 		"str %[dst], %[rseq_scratch1]\n\t"
 		"str %[len], %[rseq_scratch2]\n\t"

tools/testing/selftests/rseq/rseq-arm64.h

···
  * (C) Copyright 2018 - Will Deacon <[e-mail]>
  */
 
-#define RSEQ_SIG	0xd428bc00	/* BRK #0x45E0 */
+/*
+ * aarch64 -mbig-endian generates mixed endianness code vs data:
+ * little-endian code and big-endian data. Ensure the RSEQ_SIG signature
+ * matches code endianness.
+ */
+#define RSEQ_SIG_CODE	0xd428bc00	/* BRK #0x45E0.  */
+
+#ifdef __AARCH64EB__
+#define RSEQ_SIG_DATA	0x00bc28d4	/* BRK #0x45E0.  */
+#else
+#define RSEQ_SIG_DATA	RSEQ_SIG_CODE
+#endif
+
+#define RSEQ_SIG	RSEQ_SIG_DATA
 
 #define rseq_smp_mb()	__asm__ __volatile__ ("dmb ish" ::: "memory")
 #define rseq_smp_rmb()	__asm__ __volatile__ ("dmb ishld" ::: "memory")
···
 
 #define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, start_ip,		\
 				post_commit_offset, abort_ip)			\
-	"	.pushsection	__rseq_table, \"aw\"\n"				\
+	"	.pushsection	__rseq_cs, \"aw\"\n"				\
 	"	.balign	32\n"							\
 	__rseq_str(label) ":\n"							\
 	"	.long	" __rseq_str(version) ", " __rseq_str(flags) "\n"	\
 	"	.quad	" __rseq_str(start_ip) ", "				\
 			  __rseq_str(post_commit_offset) ", "			\
 			  __rseq_str(abort_ip) "\n"				\
+	"	.popsection\n\t"						\
+	"	.pushsection __rseq_cs_ptr_array, \"aw\"\n"				\
+	"	.quad " __rseq_str(label) "b\n"					\
 	"	.popsection\n"
 
 #define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip)	\
 	__RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip,			\
 				(post_commit_ip - start_ip), abort_ip)
+
+/*
+ * Exit points of a rseq critical section consist of all instructions outside
+ * of the critical section where a critical section can either branch to or
+ * reach through the normal course of its execution. The abort IP and the
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
+ * useful to assist debuggers stepping over the critical section.
+ */
+#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip)				\
+	"	.pushsection __rseq_exit_point_array, \"aw\"\n"			\
+	"	.quad " __rseq_str(start_ip) ", " __rseq_str(exit_ip) "\n"	\
+	"	.popsection\n"
 
 #define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs)			\
 	RSEQ_INJECT_ASM(1)							\
···
 
 #define RSEQ_ASM_DEFINE_ABORT(label, abort_label)				\
 	"	b	222f\n"							\
-	"	.inst 	"	__rseq_str(RSEQ_SIG) "\n"			\
+	"	.inst 	"	__rseq_str(RSEQ_SIG_CODE) "\n"			\
 	__rseq_str(label) ":\n"							\
 	"	b	%l[" __rseq_str(abort_label) "]\n"			\
 	"222:\n"
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(1, 2f, 3f, 4f)
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[error2])
+#endif
 		RSEQ_ASM_STORE_RSEQ_CS(2, 1b, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
 		RSEQ_INJECT_ASM(3)
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(1, 2f, 3f, 4f)
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[error2])
+#endif
 		RSEQ_ASM_STORE_RSEQ_CS(2, 1b, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
 		RSEQ_INJECT_ASM(3)
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(1, 2f, 3f, 4f)
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[error1])
+#endif
 		RSEQ_ASM_STORE_RSEQ_CS(2, 1b, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
 		RSEQ_INJECT_ASM(3)
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(1, 2f, 3f, 4f)
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[error2])
+#endif
 		RSEQ_ASM_STORE_RSEQ_CS(2, 1b, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
 		RSEQ_INJECT_ASM(3)
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(1, 2f, 3f, 4f)
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[error2])
+#endif
 		RSEQ_ASM_STORE_RSEQ_CS(2, 1b, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
 		RSEQ_INJECT_ASM(3)
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(1, 2f, 3f, 4f)
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[error2])
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[error3])
+#endif
 		RSEQ_ASM_STORE_RSEQ_CS(2, 1b, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
 		RSEQ_INJECT_ASM(3)
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(1, 2f, 3f, 4f)
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[error2])
+#endif
 		RSEQ_ASM_STORE_RSEQ_CS(2, 1b, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
 		RSEQ_INJECT_ASM(3)
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(1, 2f, 3f, 4f)
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(2f, %l[error2])
+#endif
 		RSEQ_ASM_STORE_RSEQ_CS(2, 1b, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
 		RSEQ_INJECT_ASM(3)

tools/testing/selftests/rseq/rseq-mips.h

···
  * (C) Copyright 2016-2018 - Mathieu Desnoyers <[e-mail]>
  */
 
-#define RSEQ_SIG	0x53053053
+/*
+ * RSEQ_SIG uses the break instruction. The instruction pattern is:
+ *
+ * On MIPS:
+ *	0350000d        break     0x350
+ *
+ * On nanoMIPS:
+ *      00100350        break     0x350
+ *
+ * On microMIPS:
+ *      0000d407        break     0x350
+ *
+ * For nanoMIPS32 and microMIPS, the instruction stream is encoded as 16-bit
+ * halfwords, so the signature halfwords need to be swapped accordingly for
+ * little-endian.
+ */
+#if defined(__nanomips__)
+# ifdef __MIPSEL__
+#  define RSEQ_SIG	0x03500010
+# else
+#  define RSEQ_SIG	0x00100350
+# endif
+#elif defined(__mips_micromips)
+# ifdef __MIPSEL__
+#  define RSEQ_SIG	0xd4070000
+# else
+#  define RSEQ_SIG	0x0000d407
+# endif
+#elif defined(__mips__)
+# define RSEQ_SIG	0x0350000d
+#else
+/* Unknown MIPS architecture. */
+#endif
 
 #define rseq_smp_mb()	__asm__ __volatile__ ("sync" ::: "memory")
 #define rseq_smp_rmb()	rseq_smp_mb()
···
 # error unsupported _MIPS_SZLONG
 #endif
 
-#define __RSEQ_ASM_DEFINE_TABLE(version, flags,	start_ip, \
+#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, start_ip, \
 				post_commit_offset, abort_ip) \
-		".pushsection __rseq_table, \"aw\"\n\t" \
+		".pushsection __rseq_cs, \"aw\"\n\t" \
 		".balign 32\n\t" \
+		__rseq_str(label) ":\n\t"					\
 		".word " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
 		LONG " " U32_U64_PAD(__rseq_str(start_ip)) "\n\t" \
 		LONG " " U32_U64_PAD(__rseq_str(post_commit_offset)) "\n\t" \
 		LONG " " U32_U64_PAD(__rseq_str(abort_ip)) "\n\t" \
+		".popsection\n\t" \
+		".pushsection __rseq_cs_ptr_array, \"aw\"\n\t" \
+		LONG " " U32_U64_PAD(__rseq_str(label) "b") "\n\t" \
 		".popsection\n\t"
 
-#define RSEQ_ASM_DEFINE_TABLE(start_ip, post_commit_ip, abort_ip) \
-	__RSEQ_ASM_DEFINE_TABLE(0x0, 0x0, start_ip, \
+#define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
+	__RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip, \
 				(post_commit_ip - start_ip), abort_ip)
+
+/*
+ * Exit points of a rseq critical section consist of all instructions outside
+ * of the critical section where a critical section can either branch to or
+ * reach through the normal course of its execution. The abort IP and the
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
+ * useful to assist debuggers stepping over the critical section.
+ */
+#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip) \
+		".pushsection __rseq_exit_point_array, \"aw\"\n\t" \
+		LONG " " U32_U64_PAD(__rseq_str(start_ip)) "\n\t" \
+		LONG " " U32_U64_PAD(__rseq_str(exit_ip)) "\n\t" \
+		".popsection\n\t"
 
 #define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs) \
 		RSEQ_INJECT_ASM(1) \
···
 
 	rseq_workaround_gcc_asm_size_guess();
 	__asm__ __volatile__ goto (
-		RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
···
 
 	rseq_workaround_gcc_asm_size_guess();
 	__asm__ __volatile__ goto (
-		RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
···
 
 	rseq_workaround_gcc_asm_size_guess();
 	__asm__ __volatile__ goto (
-		RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
···
 
 	rseq_workaround_gcc_asm_size_guess();
 	__asm__ __volatile__ goto (
-		RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
···
 
 	rseq_workaround_gcc_asm_size_guess();
 	__asm__ __volatile__ goto (
-		RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
···
 
 	rseq_workaround_gcc_asm_size_guess();
 	__asm__ __volatile__ goto (
-		RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error3])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
···
 
 	rseq_workaround_gcc_asm_size_guess();
 	__asm__ __volatile__ goto (
-		RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		LONG_S " %[src], %[rseq_scratch0]\n\t"
 		LONG_S "  %[dst], %[rseq_scratch1]\n\t"
 		LONG_S " %[len], %[rseq_scratch2]\n\t"
···
 
 	rseq_workaround_gcc_asm_size_guess();
 	__asm__ __volatile__ goto (
-		RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		LONG_S " %[src], %[rseq_scratch0]\n\t"
 		LONG_S " %[dst], %[rseq_scratch1]\n\t"
 		LONG_S " %[len], %[rseq_scratch2]\n\t"

tools/testing/selftests/rseq/rseq-ppc.h

···
  * (C) Copyright 2016-2018 - Boqun Feng <[e-mail]>
  */
 
-#define RSEQ_SIG	0x53053053
+/*
+ * RSEQ_SIG is used with the following trap instruction:
+ *
+ * powerpc-be:    0f e5 00 0b           twui   r5,11
+ * powerpc64-le:  0b 00 e5 0f           twui   r5,11
+ * powerpc64-be:  0f e5 00 0b           twui   r5,11
+ */
+
+#define RSEQ_SIG	0x0fe5000b
 
 #define rseq_smp_mb()		__asm__ __volatile__ ("sync"	::: "memory", "cc")
 #define rseq_smp_lwsync()	__asm__ __volatile__ ("lwsync"	::: "memory", "cc")
···
 #else /* !RSEQ_SKIP_FASTPATH */
 
 /*
- * The __rseq_table section can be used by debuggers to better handle
- * single-stepping through the restartable critical sections.
+ * The __rseq_cs_ptr_array and __rseq_cs sections can be used by debuggers to
+ * better handle single-stepping through the restartable critical sections.
  */
 
 #ifdef __PPC64__
···
 
 #define __RSEQ_ASM_DEFINE_TABLE(label, version, flags,				\
 			start_ip, post_commit_offset, abort_ip)			\
-		".pushsection __rseq_table, \"aw\"\n\t"				\
+		".pushsection __rseq_cs, \"aw\"\n\t"				\
 		".balign 32\n\t"						\
 		__rseq_str(label) ":\n\t"					\
 		".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t"	\
 		".quad " __rseq_str(start_ip) ", " __rseq_str(post_commit_offset) ", " __rseq_str(abort_ip) "\n\t" \
+		".popsection\n\t"						\
+		".pushsection __rseq_cs_ptr_array, \"aw\"\n\t"			\
+		".quad " __rseq_str(label) "b\n\t"				\
 		".popsection\n\t"
 
 #define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs)			\
···
 		"std %%r17, %[" __rseq_str(rseq_cs) "]\n\t"			\
 		__rseq_str(label) ":\n\t"
 
+/*
+ * Exit points of a rseq critical section consist of all instructions outside
+ * of the critical section where a critical section can either branch to or
+ * reach through the normal course of its execution. The abort IP and the
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
+ * useful to assist debuggers stepping over the critical section.
+ */
+#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip)			\
+		".pushsection __rseq_exit_point_array, \"aw\"\n\t"	\
+		".quad " __rseq_str(start_ip) ", " __rseq_str(exit_ip) "\n\t" \
+		".popsection\n\t"
+
 #else /* #ifdef __PPC64__ */
 
 #define STORE_WORD	"stw "
···
 
 #define __RSEQ_ASM_DEFINE_TABLE(label, version, flags,				\
 			start_ip, post_commit_offset, abort_ip)			\
-		".pushsection __rseq_table, \"aw\"\n\t"				\
+		".pushsection __rseq_cs, \"aw\"\n\t"				\
 		".balign 32\n\t"						\
 		__rseq_str(label) ":\n\t"					\
 		".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t"	\
 		/* 32-bit only supported on BE */				\
 		".long 0x0, " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) "\n\t" \
+		".popsection\n\t"					\
+		".pushsection __rseq_cs_ptr_array, \"aw\"\n\t"		\
+		".long 0x0, " __rseq_str(label) "b\n\t"			\
+		".popsection\n\t"
+
+/*
+ * Exit points of a rseq critical section consist of all instructions outside
+ * of the critical section where a critical section can either branch to or
+ * reach through the normal course of its execution. The abort IP and the
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
+ * useful to assist debuggers stepping over the critical section.
+ */
+#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip)				\
+		".pushsection __rseq_exit_point_array, \"aw\"\n\t"		\
+		/* 32-bit only supported on BE */				\
+		".long 0x0, " __rseq_str(start_ip) ", 0x0, " __rseq_str(exit_ip) "\n\t"	\
 		".popsection\n\t"
 
 #define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs)			\
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
 		/* cmp cpuid */
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
 		/* cmp cpuid */
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
 		/* cmp cpuid */
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
 		/* cmp cpuid */
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
 		/* cmp cpuid */
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error3])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
 		/* cmp cpuid */
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* setup for mempcy */
 		"mr %%r19, %[len]\n\t"
 		"mr %%r20, %[src]\n\t"
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* setup for mempcy */
 		"mr %%r19, %[len]\n\t"
 		"mr %%r20, %[src]\n\t"

tools/testing/selftests/rseq/rseq-s390.h

···
 
 #define __RSEQ_ASM_DEFINE_TABLE(label, version, flags,			\
 				start_ip, post_commit_offset, abort_ip)	\
-		".pushsection __rseq_table, \"aw\"\n\t"			\
+		".pushsection __rseq_cs, \"aw\"\n\t"			\
 		".balign 32\n\t"					\
 		__rseq_str(label) ":\n\t"				\
 		".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
 		".quad " __rseq_str(start_ip) ", " __rseq_str(post_commit_offset) ", " __rseq_str(abort_ip) "\n\t" \
+		".popsection\n\t"					\
+		".pushsection __rseq_cs_ptr_array, \"aw\"\n\t"		\
+		".quad " __rseq_str(label) "b\n\t"			\
+		".popsection\n\t"
+
+/*
+ * Exit points of a rseq critical section consist of all instructions outside
+ * of the critical section where a critical section can either branch to or
+ * reach through the normal course of its execution. The abort IP and the
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
+ * useful to assist debuggers stepping over the critical section.
+ */
+#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip)			\
+		".pushsection __rseq_exit_point_array, \"aw\"\n\t"	\
+		".quad " __rseq_str(start_ip) ", " __rseq_str(exit_ip) "\n\t" \
 		".popsection\n\t"
 
 #elif __s390__
 
 #define __RSEQ_ASM_DEFINE_TABLE(label, version, flags,			\
 				start_ip, post_commit_offset, abort_ip)	\
-		".pushsection __rseq_table, \"aw\"\n\t"			\
+		".pushsection __rseq_cs, \"aw\"\n\t"			\
 		".balign 32\n\t"					\
 		__rseq_str(label) ":\n\t"				\
 		".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
 		".long 0x0, " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) "\n\t" \
+		".popsection\n\t"					\
+		".pushsection __rseq_cs_ptr_array, \"aw\"\n\t"		\
+		".long 0x0, " __rseq_str(label) "b\n\t"			\
+		".popsection\n\t"
+
+/*
+ * Exit points of a rseq critical section consist of all instructions outside
+ * of the critical section where a critical section can either branch to or
+ * reach through the normal course of its execution. The abort IP and the
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
+ * useful to assist debuggers stepping over the critical section.
+ */
+#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip)			\
+		".pushsection __rseq_exit_point_array, \"aw\"\n\t"	\
+		".long 0x0, " __rseq_str(start_ip) ", 0x0, " __rseq_str(exit_ip) "\n\t" \
 		".popsection\n\t"
 
 #define LONG_L			"l"
···
 		".long " __rseq_str(RSEQ_SIG) "\n\t"			\
 		__rseq_str(label) ":\n\t"				\
 		teardown						\
-		"j %l[" __rseq_str(abort_label) "]\n\t"			\
+		"jg %l[" __rseq_str(abort_label) "]\n\t"		\
 		".popsection\n\t"
 
 #define RSEQ_ASM_DEFINE_CMPFAIL(label, teardown, cmpfail_label)		\
 		".pushsection __rseq_failure, \"ax\"\n\t"		\
 		__rseq_str(label) ":\n\t"				\
 		teardown						\
-		"j %l[" __rseq_str(cmpfail_label) "]\n\t"		\
+		"jg %l[" __rseq_str(cmpfail_label) "]\n\t"		\
 		".popsection\n\t"
 
 static inline __attribute__((always_inline))
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error3])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
 		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
 		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		LONG_S " %[src], %[rseq_scratch0]\n\t"
 		LONG_S " %[dst], %[rseq_scratch1]\n\t"
 		LONG_S " %[len], %[rseq_scratch2]\n\t"

tools/testing/selftests/rseq/rseq-x86.h

···
 
 #include <stdint.h>
 
+/*
+ * RSEQ_SIG is used with the following reserved undefined instructions, which
+ * trap in user-space:
+ *
+ * x86-32:    0f b9 3d 53 30 05 53      ud1    0x53053053,%edi
+ * x86-64:    0f b9 3d 53 30 05 53      ud1    0x53053053(%rip),%edi
+ */
 #define RSEQ_SIG	0x53053053
+
+/*
+ * Due to a compiler optimization bug in gcc-8 with asm goto and TLS asm input
+ * operands, we cannot use "m" input operands, and rather pass the __rseq_abi
+ * address through a "r" input operand.
+ */
+
+/* Offset of cpu_id and rseq_cs fields in struct rseq. */
+#define RSEQ_CPU_ID_OFFSET	4
+#define RSEQ_CS_OFFSET		8
 
 #ifdef __x86_64__
 
···
 
 #define __RSEQ_ASM_DEFINE_TABLE(label, version, flags,			\
 				start_ip, post_commit_offset, abort_ip)	\
-		".pushsection __rseq_table, \"aw\"\n\t"			\
+		".pushsection __rseq_cs, \"aw\"\n\t"			\
 		".balign 32\n\t"					\
 		__rseq_str(label) ":\n\t"				\
 		".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
 		".quad " __rseq_str(start_ip) ", " __rseq_str(post_commit_offset) ", " __rseq_str(abort_ip) "\n\t" \
+		".popsection\n\t"					\
+		".pushsection __rseq_cs_ptr_array, \"aw\"\n\t"		\
+		".quad " __rseq_str(label) "b\n\t"			\
 		".popsection\n\t"
+
 
 #define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
 	__RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip,		\
 				(post_commit_ip - start_ip), abort_ip)
 
+/*
+ * Exit points of a rseq critical section consist of all instructions outside
+ * of the critical section where a critical section can either branch to or
+ * reach through the normal course of its execution. The abort IP and the
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
+ * useful to assist debuggers stepping over the critical section.
+ */
+#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip)			\
+		".pushsection __rseq_exit_point_array, \"aw\"\n\t"	\
+		".quad " __rseq_str(start_ip) ", " __rseq_str(exit_ip) "\n\t" \
+		".popsection\n\t"
+
 #define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs)		\
 		RSEQ_INJECT_ASM(1)					\
 		"leaq " __rseq_str(cs_label) "(%%rip), %%rax\n\t"	\
-		"movq %%rax, %[" __rseq_str(rseq_cs) "]\n\t"		\
+		"movq %%rax, " __rseq_str(rseq_cs) "\n\t"		\
 		__rseq_str(label) ":\n\t"
 
 #define RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, label)		\
 		RSEQ_INJECT_ASM(2)					\
-		"cmpl %[" __rseq_str(cpu_id) "], %[" __rseq_str(current_cpu_id) "]\n\t" \
+		"cmpl %[" __rseq_str(cpu_id) "], " __rseq_str(current_cpu_id) "\n\t" \
 		"jnz " __rseq_str(label) "\n\t"
 
 #define RSEQ_ASM_DEFINE_ABORT(label, teardown, abort_label)		\
 		".pushsection __rseq_failure, \"ax\"\n\t"		\
-		/* Disassembler-friendly signature: nopl <sig>(%rip). */\
-		".byte 0x0f, 0x1f, 0x05\n\t"				\
+		/* Disassembler-friendly signature: ud1 <sig>(%rip),%edi. */ \
+		".byte 0x0f, 0xb9, 0x3d\n\t"				\
 		".long " __rseq_str(RSEQ_SIG) "\n\t"			\
 		__rseq_str(label) ":\n\t"				\
 		teardown						\
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
-		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi]))
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 4f)
 		RSEQ_INJECT_ASM(3)
 		"cmpq %[v], %[expect]\n\t"
 		"jnz %l[cmpfail]\n\t"
 		RSEQ_INJECT_ASM(4)
 #ifdef RSEQ_COMPARE_TWICE
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), %l[error1])
 		"cmpq %[v], %[expect]\n\t"
 		"jnz %l[error2]\n\t"
 #endif
···
 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
 		: /* gcc asm goto does not allow outputs */
 		: [cpu_id]		"r" (cpu),
-		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
-		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
+		  [rseq_abi]		"r" (&__rseq_abi),
 		  [v]			"m" (*v),
 		  [expect]		"r" (expect),
 		  [newv]		"r" (newv)
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
-		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi]))
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 4f)
 		RSEQ_INJECT_ASM(3)
 		"movq %[v], %%rbx\n\t"
 		"cmpq %%rbx, %[expectnot]\n\t"
 		"je %l[cmpfail]\n\t"
 		RSEQ_INJECT_ASM(4)
 #ifdef RSEQ_COMPARE_TWICE
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), %l[error1])
 		"movq %[v], %%rbx\n\t"
 		"cmpq %%rbx, %[expectnot]\n\t"
 		"je %l[error2]\n\t"
···
 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
 		: /* gcc asm goto does not allow outputs */
 		: [cpu_id]		"r" (cpu),
-		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
-		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
+		  [rseq_abi]		"r" (&__rseq_abi),
 		  /* final store input */
 		  [v]			"m" (*v),
 		  [expectnot]		"r" (expectnot),
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
-		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi]))
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 4f)
 		RSEQ_INJECT_ASM(3)
 #ifdef RSEQ_COMPARE_TWICE
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), %l[error1])
 #endif
 		/* final store */
 		"addq %[count], %[v]\n\t"
···
 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
 		: /* gcc asm goto does not allow outputs */
 		: [cpu_id]		"r" (cpu),
-		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
-		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
+		  [rseq_abi]		"r" (&__rseq_abi),
 		  /* final store input */
 		  [v]			"m" (*v),
 		  [count]		"er" (count)
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
-		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi]))
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 4f)
 		RSEQ_INJECT_ASM(3)
 		"cmpq %[v], %[expect]\n\t"
 		"jnz %l[cmpfail]\n\t"
 		RSEQ_INJECT_ASM(4)
 #ifdef RSEQ_COMPARE_TWICE
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), %l[error1])
 		"cmpq %[v], %[expect]\n\t"
 		"jnz %l[error2]\n\t"
 #endif
···
 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
 		: /* gcc asm goto does not allow outputs */
 		: [cpu_id]		"r" (cpu),
-		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
-		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
+		  [rseq_abi]		"r" (&__rseq_abi),
 		  /* try store input */
 		  [v2]			"m" (*v2),
 		  [newv2]		"r" (newv2),
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error3])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
-		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi]))
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 4f)
 		RSEQ_INJECT_ASM(3)
 		"cmpq %[v], %[expect]\n\t"
 		"jnz %l[cmpfail]\n\t"
···
 		"jnz %l[cmpfail]\n\t"
 		RSEQ_INJECT_ASM(5)
 #ifdef RSEQ_COMPARE_TWICE
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), %l[error1])
 		"cmpq %[v], %[expect]\n\t"
 		"jnz %l[error2]\n\t"
 		"cmpq %[v2], %[expect2]\n\t"
···
 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
 		: /* gcc asm goto does not allow outputs */
 		: [cpu_id]		"r" (cpu),
-		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
-		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
+		  [rseq_abi]		"r" (&__rseq_abi),
 		  /* cmp2 input */
 		  [v2]			"m" (*v2),
 		  [expect2]		"r" (expect2),
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		"movq %[src], %[rseq_scratch0]\n\t"
 		"movq %[dst], %[rseq_scratch1]\n\t"
 		"movq %[len], %[rseq_scratch2]\n\t"
 		/* Start rseq by storing table entry pointer into rseq_cs. */
-		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi]))
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 4f)
 		RSEQ_INJECT_ASM(3)
 		"cmpq %[v], %[expect]\n\t"
 		"jnz 5f\n\t"
 		RSEQ_INJECT_ASM(4)
 #ifdef RSEQ_COMPARE_TWICE
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 6f)
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 6f)
 		"cmpq %[v], %[expect]\n\t"
 		"jnz 7f\n\t"
 #endif
···
 #endif
 		: /* gcc asm goto does not allow outputs */
 		: [cpu_id]		"r" (cpu),
-		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
-		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
+		  [rseq_abi]		"r" (&__rseq_abi),
 		  /* final store input */
 		  [v]			"m" (*v),
 		  [expect]		"r" (expect),
···
  */
 #define __RSEQ_ASM_DEFINE_TABLE(label, version, flags,			\
 				start_ip, post_commit_offset, abort_ip)	\
-		".pushsection __rseq_table, \"aw\"\n\t"			\
+		".pushsection __rseq_cs, \"aw\"\n\t"			\
 		".balign 32\n\t"					\
 		__rseq_str(label) ":\n\t"				\
 		".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
 		".long " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) ", 0x0\n\t" \
+		".popsection\n\t"					\
+		".pushsection __rseq_cs_ptr_array, \"aw\"\n\t"		\
+		".long " __rseq_str(label) "b, 0x0\n\t"			\
 		".popsection\n\t"
 
 #define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
 	__RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip,		\
 				(post_commit_ip - start_ip), abort_ip)
 
+/*
+ * Exit points of a rseq critical section consist of all instructions outside
+ * of the critical section where a critical section can either branch to or
+ * reach through the normal course of its execution. The abort IP and the
+ * post-commit IP are already part of the __rseq_cs section and should not be
+ * explicitly defined as additional exit points. Knowing all exit points is
+ * useful to assist debuggers stepping over the critical section.
+ */
+#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip)			\
+		".pushsection __rseq_exit_point_array, \"aw\"\n\t"	\
+		".long " __rseq_str(start_ip) ", 0x0, " __rseq_str(exit_ip) ", 0x0\n\t" \
+		".popsection\n\t"
+
 #define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs)		\
 		RSEQ_INJECT_ASM(1)					\
-		"movl $" __rseq_str(cs_label) ", %[rseq_cs]\n\t"	\
+		"movl $" __rseq_str(cs_label) ", " __rseq_str(rseq_cs) "\n\t"	\
 		__rseq_str(label) ":\n\t"
 
 #define RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, label)		\
 		RSEQ_INJECT_ASM(2)					\
-		"cmpl %[" __rseq_str(cpu_id) "], %[" __rseq_str(current_cpu_id) "]\n\t" \
+		"cmpl %[" __rseq_str(cpu_id) "], " __rseq_str(current_cpu_id) "\n\t" \
 		"jnz " __rseq_str(label) "\n\t"
 
 #define RSEQ_ASM_DEFINE_ABORT(label, teardown, abort_label)		\
 		".pushsection __rseq_failure, \"ax\"\n\t"		\
-		/* Disassembler-friendly signature: nopl <sig>. */	\
-		".byte 0x0f, 0x1f, 0x05\n\t"				\
+		/* Disassembler-friendly signature: ud1 <sig>,%edi. */	\
+		".byte 0x0f, 0xb9, 0x3d\n\t"				\
 		".long " __rseq_str(RSEQ_SIG) "\n\t"			\
 		__rseq_str(label) ":\n\t"				\
 		teardown						\
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
-		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi]))
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 4f)
 		RSEQ_INJECT_ASM(3)
 		"cmpl %[v], %[expect]\n\t"
 		"jnz %l[cmpfail]\n\t"
 		RSEQ_INJECT_ASM(4)
 #ifdef RSEQ_COMPARE_TWICE
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), %l[error1])
 		"cmpl %[v], %[expect]\n\t"
 		"jnz %l[error2]\n\t"
 #endif
···
 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
 		: /* gcc asm goto does not allow outputs */
 		: [cpu_id]		"r" (cpu),
-		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
-		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
+		  [rseq_abi]		"r" (&__rseq_abi),
 		  [v]			"m" (*v),
 		  [expect]		"r" (expect),
 		  [newv]		"r" (newv)
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
-		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi]))
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 4f)
 		RSEQ_INJECT_ASM(3)
 		"movl %[v], %%ebx\n\t"
 		"cmpl %%ebx, %[expectnot]\n\t"
 		"je %l[cmpfail]\n\t"
 		RSEQ_INJECT_ASM(4)
 #ifdef RSEQ_COMPARE_TWICE
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), %l[error1])
 		"movl %[v], %%ebx\n\t"
 		"cmpl %%ebx, %[expectnot]\n\t"
 		"je %l[error2]\n\t"
···
 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
 		: /* gcc asm goto does not allow outputs */
 		: [cpu_id]		"r" (cpu),
-		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
-		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
+		  [rseq_abi]		"r" (&__rseq_abi),
 		  /* final store input */
 		  [v]			"m" (*v),
 		  [expectnot]		"r" (expectnot),
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
-		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi]))
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 4f)
 		RSEQ_INJECT_ASM(3)
 #ifdef RSEQ_COMPARE_TWICE
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), %l[error1])
 #endif
 		/* final store */
 		"addl %[count], %[v]\n\t"
···
 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
 		: /* gcc asm goto does not allow outputs */
 		: [cpu_id]		"r" (cpu),
-		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
-		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
+		  [rseq_abi]		"r" (&__rseq_abi),
 		  /* final store input */
 		  [v]			"m" (*v),
 		  [count]		"ir" (count)
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
-		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi]))
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 4f)
 		RSEQ_INJECT_ASM(3)
 		"cmpl %[v], %[expect]\n\t"
 		"jnz %l[cmpfail]\n\t"
 		RSEQ_INJECT_ASM(4)
 #ifdef RSEQ_COMPARE_TWICE
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), %l[error1])
 		"cmpl %[v], %[expect]\n\t"
 		"jnz %l[error2]\n\t"
 #endif
···
 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
 		: /* gcc asm goto does not allow outputs */
 		: [cpu_id]		"r" (cpu),
-		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
-		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
+		  [rseq_abi]		"r" (&__rseq_abi),
 		  /* try store input */
 		  [v2]			"m" (*v2),
 		  [newv2]		"m" (newv2),
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
-		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi]))
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 4f)
 		RSEQ_INJECT_ASM(3)
 		"movl %[expect], %%eax\n\t"
 		"cmpl %[v], %%eax\n\t"
 		"jnz %l[cmpfail]\n\t"
 		RSEQ_INJECT_ASM(4)
 #ifdef RSEQ_COMPARE_TWICE
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), %l[error1])
 		"movl %[expect], %%eax\n\t"
 		"cmpl %[v], %%eax\n\t"
 		"jnz %l[error2]\n\t"
···
 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
 		: /* gcc asm goto does not allow outputs */
 		: [cpu_id]		"r" (cpu),
-		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
-		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
+		  [rseq_abi]		"r" (&__rseq_abi),
 		  /* try store input */
 		  [v2]			"m" (*v2),
 		  [newv2]		"r" (newv2),
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error3])
+#endif
 		/* Start rseq by storing table entry pointer into rseq_cs. */
-		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi]))
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 4f)
 		RSEQ_INJECT_ASM(3)
 		"cmpl %[v], %[expect]\n\t"
 		"jnz %l[cmpfail]\n\t"
···
 		"jnz %l[cmpfail]\n\t"
 		RSEQ_INJECT_ASM(5)
 #ifdef RSEQ_COMPARE_TWICE
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), %l[error1])
 		"cmpl %[v], %[expect]\n\t"
 		"jnz %l[error2]\n\t"
 		"cmpl %[expect2], %[v2]\n\t"
···
 		RSEQ_ASM_DEFINE_ABORT(4, "", abort)
 		: /* gcc asm goto does not allow outputs */
 		: [cpu_id]		"r" (cpu),
-		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
-		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
+		  [rseq_abi]		"r" (&__rseq_abi),
 		  /* cmp2 input */
 		  [v2]			"m" (*v2),
 		  [expect2]		"r" (expect2),
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		"movl %[src], %[rseq_scratch0]\n\t"
 		"movl %[dst], %[rseq_scratch1]\n\t"
 		"movl %[len], %[rseq_scratch2]\n\t"
 		/* Start rseq by storing table entry pointer into rseq_cs. */
-		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi]))
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 4f)
 		RSEQ_INJECT_ASM(3)
 		"movl %[expect], %%eax\n\t"
 		"cmpl %%eax, %[v]\n\t"
 		"jnz 5f\n\t"
 		RSEQ_INJECT_ASM(4)
 #ifdef RSEQ_COMPARE_TWICE
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 6f)
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 6f)
 		"movl %[expect], %%eax\n\t"
 		"cmpl %%eax, %[v]\n\t"
 		"jnz 7f\n\t"
···
 #endif
 		: /* gcc asm goto does not allow outputs */
 		: [cpu_id]		"r" (cpu),
-		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
-		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
+		  [rseq_abi]		"r" (&__rseq_abi),
 		  /* final store input */
 		  [v]			"m" (*v),
 		  [expect]		"m" (expect),
···
 
 	__asm__ __volatile__ goto (
 		RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail])
+#ifdef RSEQ_COMPARE_TWICE
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1])
+		RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2])
+#endif
 		"movl %[src], %[rseq_scratch0]\n\t"
 		"movl %[dst], %[rseq_scratch1]\n\t"
 		"movl %[len], %[rseq_scratch2]\n\t"
 		/* Start rseq by storing table entry pointer into rseq_cs. */
-		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+		RSEQ_ASM_STORE_RSEQ_CS(1, 3b, RSEQ_CS_OFFSET(%[rseq_abi]))
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 4f)
 		RSEQ_INJECT_ASM(3)
 		"movl %[expect], %%eax\n\t"
 		"cmpl %%eax, %[v]\n\t"
 		"jnz 5f\n\t"
 		RSEQ_INJECT_ASM(4)
 #ifdef RSEQ_COMPARE_TWICE
-		RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 6f)
+		RSEQ_ASM_CMP_CPU_ID(cpu_id, RSEQ_CPU_ID_OFFSET(%[rseq_abi]), 6f)
 		"movl %[expect], %%eax\n\t"
 		"cmpl %%eax, %[v]\n\t"
 		"jnz 7f\n\t"
···
 #endif
 		: /* gcc asm goto does not allow outputs */
 		: [cpu_id]		"r" (cpu),
-		  [current_cpu_id]	"m" (__rseq_abi.cpu_id),
-		  [rseq_cs]		"m" (__rseq_abi.rseq_cs),
+		  [rseq_abi]		"r" (&__rseq_abi),
 		  /* final store input */
 		  [v]			"m" (*v),
 		  [expect]		"m" (expect),

tools/testing/selftests/rseq/rseq.c

···
 #include <syscall.h>
 #include <assert.h>
 #include <signal.h>
+#include <limits.h>
 
 #include "rseq.h"
 
 #define ARRAY_SIZE(arr)	(sizeof(arr) / sizeof((arr)[0]))
 
-__attribute__((tls_model("initial-exec"))) __thread
-volatile struct rseq __rseq_abi = {
+__thread volatile struct rseq __rseq_abi = {
 	.cpu_id = RSEQ_CPU_ID_UNINITIALIZED,
 };
 
-static __attribute__((tls_model("initial-exec"))) __thread
-volatile int refcount;
+/*
+ * Shared with other libraries. This library may take rseq ownership if it is
+ * still 0 when executing the library constructor. Set to 1 by library
+ * constructor when handling rseq. Set to 0 in destructor if handling rseq.
+ */
+int __rseq_handled;
+
+/* Whether this library have ownership of rseq registration. */
+static int rseq_ownership;
+
+static __thread volatile uint32_t __rseq_refcount;
 
 static void signal_off_save(sigset_t *oldset)
 {
···
 	int rc, ret = 0;
 	sigset_t oldset;
 
+	if (!rseq_ownership)
+		return 0;
 	signal_off_save(&oldset);
-	if (refcount++)
+	if (__rseq_refcount == UINT_MAX) {
+		ret = -1;
+		goto end;
+	}
+	if (__rseq_refcount++)
 		goto end;
 	rc = sys_rseq(&__rseq_abi, sizeof(struct rseq), 0, RSEQ_SIG);
 	if (!rc) {
···
 		goto end;
 	}
 	if (errno != EBUSY)
-		__rseq_abi.cpu_id = -2;
+		__rseq_abi.cpu_id = RSEQ_CPU_ID_REGISTRATION_FAILED;
 	ret = -1;
-	refcount--;
+	__rseq_refcount--;
 end:
 	signal_restore(oldset);
 	return ret;
···
 	int rc, ret = 0;
 	sigset_t oldset;
 
+	if (!rseq_ownership)
+		return 0;
 	signal_off_save(&oldset);
-	if (--refcount)
+	if (!__rseq_refcount) {
+		ret = -1;
+		goto end;
+	}
+	if (--__rseq_refcount)
 		goto end;
 	rc = sys_rseq(&__rseq_abi, sizeof(struct rseq),
 		      RSEQ_FLAG_UNREGISTER, RSEQ_SIG);
 	if (!rc)
 		goto end;
+	__rseq_refcount = 1;
 	ret = -1;
 end:
 	signal_restore(oldset);
···
 		abort();
 	}
 	return cpu;
+}
+
+void __attribute__((constructor)) rseq_init(void)
+{
+	/* Check whether rseq is handled by another library. */
+	if (__rseq_handled)
+		return;
+	__rseq_handled = 1;
+	rseq_ownership = 1;
+}
+
+void __attribute__((destructor)) rseq_fini(void)
+{
+	if (!rseq_ownership)
+		return;
+	__rseq_handled = 0;
+	rseq_ownership = 0;
 }

tools/testing/selftests/rseq/rseq.h

···
 #endif
 
 extern __thread volatile struct rseq __rseq_abi;
+extern int __rseq_handled;
 
 #define rseq_likely(x)		__builtin_expect(!!(x), 1)
 #define rseq_unlikely(x)	__builtin_expect(!!(x), 0)

tools/testing/selftests/sigaltstack/sas.c

···
 	int err;
 
 	ksft_print_header();
+	ksft_set_plan(3);
 
 	sigemptyset(&act.sa_mask);
 	act.sa_flags = SA_ONSTACK | SA_SIGINFO;

tools/testing/selftests/sync/sync_test.c

···
 	int err;
 
 	ksft_print_header();
+	ksft_set_plan(3 + 7);
 
 	sync_api_supported();