Merge tag 'nolibc.2023.02.06a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull nolibc updates from Paul McKenney:

 - Add s390 support

 - Add support for the ARM Thumb1 instruction set

 - Fix O_* flags definitions for open() and fcntl()

 - Make errno a weak symbol instead of a static variable

 - Export environ as a weak symbol

 - Export _auxv as a weak symbol for auxilliary vector retrieval

 - Implement getauxval() and getpagesize()

 - Further improve self tests, including permitting userland testing of
   the nolibc library

* tag 'nolibc.2023.02.06a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (28 commits)
  selftests/nolibc: Add a "run-user" target to test the program in user land
  selftests/nolibc: Support "x86_64" for arch name
  selftests/nolibc: Add `getpagesize(2)` selftest
  nolibc/sys: Implement `getpagesize(2)` function
  nolibc/stdlib: Implement `getauxval(3)` function
  tools/nolibc: add auxiliary vector retrieval for s390
  tools/nolibc: add auxiliary vector retrieval for mips
  tools/nolibc: add auxiliary vector retrieval for riscv
  tools/nolibc: add auxiliary vector retrieval for arm
  tools/nolibc: add auxiliary vector retrieval for arm64
  tools/nolibc: add auxiliary vector retrieval for x86_64
  tools/nolibc: add auxiliary vector retrieval for i386
  tools/nolibc: export environ as a weak symbol on s390
  tools/nolibc: export environ as a weak symbol on riscv
  tools/nolibc: export environ as a weak symbol on mips
  tools/nolibc: export environ as a weak symbol on arm
  tools/nolibc: export environ as a weak symbol on arm64
  tools/nolibc: export environ as a weak symbol on i386
  tools/nolibc: export environ as a weak symbol on x86_64
  tools/nolibc: make errno a weak symbol instead of a static one
  ...

4 files changed, 53 insertions, 2 deletions

diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index 22f1e1d73fa8..8fe61d3e3cce 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/tools/testing/selftests/nolibc/Makefile
@@ -14,21 +14,25 @@ endif
 
 # kernel image names by architecture
 IMAGE_i386    = arch/x86/boot/bzImage
+IMAGE_x86_64  = arch/x86/boot/bzImage
 IMAGE_x86     = arch/x86/boot/bzImage
 IMAGE_arm64   = arch/arm64/boot/Image
 IMAGE_arm     = arch/arm/boot/zImage
 IMAGE_mips    = vmlinuz
 IMAGE_riscv   = arch/riscv/boot/Image
+IMAGE_s390    = arch/s390/boot/bzImage
 IMAGE         = $(IMAGE_$(ARCH))
 IMAGE_NAME    = $(notdir $(IMAGE))
 
 # default kernel configurations that appear to be usable
 DEFCONFIG_i386    = defconfig
+DEFCONFIG_x86_64  = defconfig
 DEFCONFIG_x86     = defconfig
 DEFCONFIG_arm64   = defconfig
 DEFCONFIG_arm     = multi_v7_defconfig
 DEFCONFIG_mips    = malta_defconfig
 DEFCONFIG_riscv   = defconfig
+DEFCONFIG_s390    = defconfig
 DEFCONFIG         = $(DEFCONFIG_$(ARCH))
 
 # optional tests to run (default = all)
@@ -36,20 +40,24 @@ TEST =
 
 # QEMU_ARCH: arch names used by qemu
 QEMU_ARCH_i386    = i386
+QEMU_ARCH_x86_64  = x86_64
 QEMU_ARCH_x86     = x86_64
 QEMU_ARCH_arm64   = aarch64
 QEMU_ARCH_arm     = arm
 QEMU_ARCH_mips    = mipsel  # works with malta_defconfig
 QEMU_ARCH_riscv   = riscv64
+QEMU_ARCH_s390    = s390x
 QEMU_ARCH         = $(QEMU_ARCH_$(ARCH))
 
 # QEMU_ARGS : some arch-specific args to pass to qemu
 QEMU_ARGS_i386    = -M pc -append "console=ttyS0,9600 i8042.noaux panic=-1 $(TEST:%=NOLIBC_TEST=%)"
+QEMU_ARGS_x86_64  = -M pc -append "console=ttyS0,9600 i8042.noaux panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_x86     = -M pc -append "console=ttyS0,9600 i8042.noaux panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_arm64   = -M virt -cpu cortex-a53 -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_arm     = -M virt -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_mips    = -M malta -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_riscv   = -M virt -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
+QEMU_ARGS_s390    = -M s390-ccw-virtio -m 1G -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS         = $(QEMU_ARGS_$(ARCH))
 
 # OUTPUT is only set when run from the main makefile, otherwise
@@ -62,7 +70,8 @@ else
 Q=@
 endif
 
-CFLAGS  ?= -Os -fno-ident -fno-asynchronous-unwind-tables
+CFLAGS_s390 = -m64
+CFLAGS  ?= -Os -fno-ident -fno-asynchronous-unwind-tables $(CFLAGS_$(ARCH))
 LDFLAGS := -s
 
 help:
@@ -71,6 +80,7 @@ help:
 	@echo "  help         this help"
 	@echo "  sysroot      create the nolibc sysroot here (uses \$$ARCH)"
 	@echo "  nolibc-test  build the executable (uses \$$CC and \$$CROSS_COMPILE)"
+	@echo "  run-user     runs the executable under QEMU (uses \$$ARCH, \$$TEST)"
 	@echo "  initramfs    prepare the initramfs with nolibc-test"
 	@echo "  defconfig    create a fresh new default config (uses \$$ARCH)"
 	@echo "  kernel       (re)build the kernel with the initramfs (uses \$$ARCH)"
@@ -104,6 +114,11 @@ nolibc-test: nolibc-test.c sysroot/$(ARCH)/include
 	$(QUIET_CC)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ \
 	  -nostdlib -static -Isysroot/$(ARCH)/include $< -lgcc
 
+# qemu user-land test
+run-user: nolibc-test
+	$(Q)qemu-$(QEMU_ARCH) ./nolibc-test > "$(CURDIR)/run.out" || :
+	$(Q)grep -w FAIL "$(CURDIR)/run.out" && echo "See all results in $(CURDIR)/run.out" || echo "$$(grep -c ^[0-9].*OK $(CURDIR)/run.out) test(s) passed."
+
 initramfs: nolibc-test
 	$(QUIET_MKDIR)mkdir -p initramfs
 	$(call QUIET_INSTALL, initramfs/init)
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index f14f5076fb6d..c4a0c915139c 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -442,6 +442,35 @@ int test_getdents64(const char *dir)
 	return ret;
 }
 
+static int test_getpagesize(void)
+{
+	long x = getpagesize();
+	int c;
+
+	if (x < 0)
+		return x;
+
+#if defined(__x86_64__) || defined(__i386__) || defined(__i486__) || defined(__i586__) || defined(__i686__)
+	/*
+	 * x86 family is always 4K page.
+	 */
+	c = (x == 4096);
+#elif defined(__aarch64__)
+	/*
+	 * Linux aarch64 supports three values of page size: 4K, 16K, and 64K
+	 * which are selected at kernel compilation time.
+	 */
+	c = (x == 4096 || x == (16 * 1024) || x == (64 * 1024));
+#else
+	/*
+	 * Assuming other architectures must have at least 4K page.
+	 */
+	c = (x >= 4096);
+#endif
+
+	return !c;
+}
+
 /* Run syscall tests between IDs <min> and <max>.
  * Return 0 on success, non-zero on failure.
  */
@@ -502,6 +531,7 @@ int run_syscall(int min, int max)
 		CASE_TEST(gettimeofday_bad2); EXPECT_SYSER(1, gettimeofday(NULL, (void *)1), -1, EFAULT); break;
 		CASE_TEST(gettimeofday_bad2); EXPECT_SYSER(1, gettimeofday(NULL, (void *)1), -1, EFAULT); break;
 #endif
+		CASE_TEST(getpagesize);       EXPECT_SYSZR(1, test_getpagesize()); break;
 		CASE_TEST(ioctl_tiocinq);     EXPECT_SYSZR(1, ioctl(0, TIOCINQ, &tmp)); break;
 		CASE_TEST(ioctl_tiocinq);     EXPECT_SYSZR(1, ioctl(0, TIOCINQ, &tmp)); break;
 		CASE_TEST(link_root1);        EXPECT_SYSER(1, link("/", "/"), -1, EEXIST); break;
diff --git a/tools/testing/selftests/rcutorture/bin/functions.sh b/tools/testing/selftests/rcutorture/bin/functions.sh
index 66d0414d8e4b..b52d5069563c 100644
--- a/tools/testing/selftests/rcutorture/bin/functions.sh
+++ b/tools/testing/selftests/rcutorture/bin/functions.sh
@@ -159,6 +159,9 @@ identify_boot_image () {
 		qemu-system-aarch64)
 			echo arch/arm64/boot/Image
 			;;
+		qemu-system-s390x)
+			echo arch/s390/boot/bzImage
+			;;
 		*)
 			echo vmlinux
 			;;
@@ -184,6 +187,9 @@ identify_qemu () {
 	elif echo $u | grep -q aarch64
 	then
 		echo qemu-system-aarch64
+	elif echo $u | grep -q 'IBM S/390'
+	then
+		echo qemu-system-s390x
 	elif uname -a | grep -q ppc64
 	then
 		echo qemu-system-ppc64
diff --git a/tools/testing/selftests/rcutorture/bin/mkinitrd.sh b/tools/testing/selftests/rcutorture/bin/mkinitrd.sh
index 70d62fd0d31d..71f0dfbb2a6d 100755
--- a/tools/testing/selftests/rcutorture/bin/mkinitrd.sh
+++ b/tools/testing/selftests/rcutorture/bin/mkinitrd.sh
@@ -64,7 +64,7 @@ ___EOF___
 # build using nolibc on supported archs (smaller executable) and fall
 # back to regular glibc on other ones.
 if echo -e "#if __x86_64__||__i386__||__i486__||__i586__||__i686__" \
-           "||__ARM_EABI__||__aarch64__\nyes\n#endif" \
+           "||__ARM_EABI__||__aarch64__||__s390x__\nyes\n#endif" \
    | ${CROSS_COMPILE}gcc -E -nostdlib -xc - \
    | grep -q '^yes'; then
 	# architecture supported by nolibc