Merge tag 'nolibc.2023.10.23a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull nolibc updates from Paul McKenney:

 - Add stdarg.h header and a few additional system-call upgrades

 - Add support for constructors and destructors

 - Add tests to verify the ability to link multiple .o files against
   nolibc

 - Numerous string-function optimizations and improvements

 - Prevent redundant kernel relinks by avoiding embedding of initramfs
   into the kernel image

 - Allow building i386 with multiarch compiler and make ppc64le use
   qemu-system-ppc64

 - Miscellaneous fixups, including addition of -nostdinc for
   nolibc-test, avoiding -Wstringop-overflow warnings, and avoiding
   unused parameter warnings for ENOSYS fallbacks

* tag 'nolibc.2023.10.23a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
  selftests/nolibc: add tests for multi-object linkage
  selftests/nolibc: use qemu-system-ppc64 for ppc64le
  tools/nolibc: add support for constructors and destructors
  tools/nolibc: drop test for getauxval(AT_PAGESZ)
  tools/nolibc: automatically detect necessity to use pselect6
  tools/nolibc: don't define new syscall number
  tools/nolibc: avoid unused parameter warnings for ENOSYS fallbacks
  selftests/nolibc: allow building i386 with multiarch compiler
  selftests/nolibc: don't embed initramfs into kernel image
  selftests/nolibc: libc-test: avoid -Wstringop-overflow warnings
  tools/nolibc: string: Remove the `_nolibc_memcpy_up()` function
  tools/nolibc: string: Remove the `_nolibc_memcpy_down()` function
  tools/nolibc: x86-64: Use `rep stosb` for `memset()`
  tools/nolibc: x86-64: Use `rep movsb` for `memcpy()` and `memmove()`
  selftests/nolibc: use -nostdinc for nolibc-test
  tools/nolibc: add stdarg.h header

5 files changed, 94 insertions, 27 deletions

diff --git a/tools/testing/selftests/nolibc/.gitignore b/tools/testing/selftests/nolibc/.gitignore
index 52f613cdad54..5119f9f7afd2 100644
--- a/tools/testing/selftests/nolibc/.gitignore
+++ b/tools/testing/selftests/nolibc/.gitignore
@@ -1,4 +1,5 @@
 /initramfs/
+/initramfs.cpio
 /libc-test
 /nolibc-test
 /run.out
diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index dfe66776a331..a0fc07253baf 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/tools/testing/selftests/nolibc/Makefile
@@ -82,7 +82,7 @@ QEMU_ARCH_arm        = arm
 QEMU_ARCH_mips       = mipsel  # works with malta_defconfig
 QEMU_ARCH_ppc        = ppc
 QEMU_ARCH_ppc64      = ppc64
-QEMU_ARCH_ppc64le    = ppc64le
+QEMU_ARCH_ppc64le    = ppc64
 QEMU_ARCH_riscv      = riscv64
 QEMU_ARCH_s390       = s390x
 QEMU_ARCH_loongarch  = loongarch64
@@ -113,6 +113,7 @@ else
 Q=@
 endif
 
+CFLAGS_i386 = $(call cc-option,-m32)
 CFLAGS_ppc = -m32 -mbig-endian -mno-vsx $(call cc-option,-mmultiple)
 CFLAGS_ppc64 = -m64 -mbig-endian -mno-vsx $(call cc-option,-mmultiple)
 CFLAGS_ppc64le = -m64 -mlittle-endian -mno-vsx $(call cc-option,-mabi=elfv2)
@@ -131,18 +132,20 @@ REPORT  ?= awk '/\[OK\][\r]*$$/{p++} /\[FAIL\][\r]*$$/{if (!f) printf("\n"); f++
 
 help:
 	@echo "Supported targets under selftests/nolibc:"
-	@echo "  all          call the \"run\" target below"
-	@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 "  libc-test    build an executable using the compiler's default libc instead"
-	@echo "  run-user     runs the executable under QEMU (uses \$$XARCH, \$$TEST)"
-	@echo "  initramfs    prepare the initramfs with nolibc-test"
-	@echo "  defconfig    create a fresh new default config (uses \$$XARCH)"
-	@echo "  kernel       (re)build the kernel with the initramfs (uses \$$XARCH)"
-	@echo "  run          runs the kernel in QEMU after building it (uses \$$XARCH, \$$TEST)"
-	@echo "  rerun        runs a previously prebuilt kernel in QEMU (uses \$$XARCH, \$$TEST)"
-	@echo "  clean        clean the sysroot, initramfs, build and output files"
+	@echo "  all               call the \"run\" target below"
+	@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 "  libc-test         build an executable using the compiler's default libc instead"
+	@echo "  run-user          runs the executable under QEMU (uses \$$XARCH, \$$TEST)"
+	@echo "  initramfs.cpio    prepare the initramfs archive with nolibc-test"
+	@echo "  initramfs         prepare the initramfs tree with nolibc-test"
+	@echo "  defconfig         create a fresh new default config (uses \$$XARCH)"
+	@echo "  kernel            (re)build the kernel (uses \$$XARCH)"
+	@echo "  kernel-standalone (re)build the kernel with the initramfs (uses \$$XARCH)"
+	@echo "  run               runs the kernel in QEMU after building it (uses \$$XARCH, \$$TEST)"
+	@echo "  rerun             runs a previously prebuilt kernel in QEMU (uses \$$XARCH, \$$TEST)"
+	@echo "  clean             clean the sysroot, initramfs, build and output files"
 	@echo ""
 	@echo "The output file is \"run.out\". Test ranges may be passed using \$$TEST."
 	@echo ""
@@ -168,17 +171,17 @@ sysroot/$(ARCH)/include:
 	$(Q)mv sysroot/sysroot sysroot/$(ARCH)
 
 ifneq ($(NOLIBC_SYSROOT),0)
-nolibc-test: nolibc-test.c sysroot/$(ARCH)/include
+nolibc-test: nolibc-test.c nolibc-test-linkage.c sysroot/$(ARCH)/include
 	$(QUIET_CC)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ \
-	  -nostdlib -static -Isysroot/$(ARCH)/include $< -lgcc
+	  -nostdlib -nostdinc -static -Isysroot/$(ARCH)/include nolibc-test.c nolibc-test-linkage.c -lgcc
 else
-nolibc-test: nolibc-test.c
+nolibc-test: nolibc-test.c nolibc-test-linkage.c
 	$(QUIET_CC)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ \
-	  -nostdlib -static -include ../../../include/nolibc/nolibc.h $< -lgcc
+	  -nostdlib -static -include ../../../include/nolibc/nolibc.h nolibc-test.c nolibc-test-linkage.c -lgcc
 endif
 
-libc-test: nolibc-test.c
-	$(QUIET_CC)$(HOSTCC) -o $@ $<
+libc-test: nolibc-test.c nolibc-test-linkage.c
+	$(QUIET_CC)$(HOSTCC) -o $@ nolibc-test.c nolibc-test-linkage.c
 
 # local libc-test
 run-libc-test: libc-test
@@ -195,6 +198,9 @@ run-user: nolibc-test
 	$(Q)qemu-$(QEMU_ARCH) ./nolibc-test > "$(CURDIR)/run.out" || :
 	$(Q)$(REPORT) $(CURDIR)/run.out
 
+initramfs.cpio: kernel nolibc-test
+	$(QUIET_GEN)echo 'file /init nolibc-test 755 0 0' | $(srctree)/usr/gen_init_cpio - > initramfs.cpio
+
 initramfs: nolibc-test
 	$(QUIET_MKDIR)mkdir -p initramfs
 	$(call QUIET_INSTALL, initramfs/init)
@@ -203,17 +209,20 @@ initramfs: nolibc-test
 defconfig:
 	$(Q)$(MAKE) -C $(srctree) ARCH=$(ARCH) CC=$(CC) CROSS_COMPILE=$(CROSS_COMPILE) mrproper $(DEFCONFIG) prepare
 
-kernel: initramfs
+kernel:
+	$(Q)$(MAKE) -C $(srctree) ARCH=$(ARCH) CC=$(CC) CROSS_COMPILE=$(CROSS_COMPILE) $(IMAGE_NAME)
+
+kernel-standalone: initramfs
 	$(Q)$(MAKE) -C $(srctree) ARCH=$(ARCH) CC=$(CC) CROSS_COMPILE=$(CROSS_COMPILE) $(IMAGE_NAME) CONFIG_INITRAMFS_SOURCE=$(CURDIR)/initramfs
 
 # run the tests after building the kernel
-run: kernel
-	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(srctree)/$(IMAGE)" -serial stdio $(QEMU_ARGS) > "$(CURDIR)/run.out"
+run: kernel initramfs.cpio
+	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(srctree)/$(IMAGE)" -initrd initramfs.cpio -serial stdio $(QEMU_ARGS) > "$(CURDIR)/run.out"
 	$(Q)$(REPORT) $(CURDIR)/run.out
 
 # re-run the tests from an existing kernel
 rerun:
-	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(srctree)/$(IMAGE)" -serial stdio $(QEMU_ARGS) > "$(CURDIR)/run.out"
+	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(srctree)/$(IMAGE)" -initrd initramfs.cpio -serial stdio $(QEMU_ARGS) > "$(CURDIR)/run.out"
 	$(Q)$(REPORT) $(CURDIR)/run.out
 
 # report with existing test log
@@ -227,6 +236,8 @@ clean:
 	$(Q)rm -f nolibc-test
 	$(call QUIET_CLEAN, libc-test)
 	$(Q)rm -f libc-test
+	$(call QUIET_CLEAN, initramfs.cpio)
+	$(Q)rm -rf initramfs.cpio
 	$(call QUIET_CLEAN, initramfs)
 	$(Q)rm -rf initramfs
 	$(call QUIET_CLEAN, run.out)
diff --git a/tools/testing/selftests/nolibc/nolibc-test-linkage.c b/tools/testing/selftests/nolibc/nolibc-test-linkage.c
new file mode 100644
index 000000000000..5ff4c8a1db2a
--- /dev/null
+++ b/tools/testing/selftests/nolibc/nolibc-test-linkage.c
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include "nolibc-test-linkage.h"
+
+#ifndef NOLIBC
+#include <errno.h>
+#endif
+
+void *linkage_test_errno_addr(void)
+{
+	return &errno;
+}
+
+int linkage_test_constructor_test_value;
+
+__attribute__((constructor))
+static void constructor1(void)
+{
+	linkage_test_constructor_test_value = 2;
+}
+
+__attribute__((constructor))
+static void constructor2(void)
+{
+	linkage_test_constructor_test_value *= 3;
+}
diff --git a/tools/testing/selftests/nolibc/nolibc-test-linkage.h b/tools/testing/selftests/nolibc/nolibc-test-linkage.h
new file mode 100644
index 000000000000..c66473070d73
--- /dev/null
+++ b/tools/testing/selftests/nolibc/nolibc-test-linkage.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _NOLIBC_TEST_LINKAGE_H
+#define _NOLIBC_TEST_LINKAGE_H
+
+void *linkage_test_errno_addr(void);
+extern int linkage_test_constructor_test_value;
+
+#endif /* _NOLIBC_TEST_LINKAGE_H */
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index fb3bf91462e2..2f10541e6f38 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -41,6 +41,8 @@
 #endif
 #endif
 
+#include "nolibc-test-linkage.h"
+
 /* for the type of int_fast16_t and int_fast32_t, musl differs from glibc and nolibc */
 #define SINT_MAX_OF_TYPE(type) (((type)1 << (sizeof(type) * 8 - 2)) - (type)1 + ((type)1 << (sizeof(type) * 8 - 2)))
 #define SINT_MIN_OF_TYPE(type) (-SINT_MAX_OF_TYPE(type) - 1)
@@ -57,6 +59,9 @@ static int test_argc;
 /* will be used by some test cases as readable file, please don't write it */
 static const char *argv0;
 
+/* will be used by constructor tests */
+static int constructor_test_value;
+
 /* definition of a series of tests */
 struct test {
 	const char *name;              /* test name */
@@ -594,6 +599,19 @@ int expect_strne(const char *expr, int llen, const char *cmp)
 #define CASE_TEST(name) \
 	case __LINE__: llen += printf("%d %s", test, #name);
 
+/* constructors validate that they are executed in definition order */
+__attribute__((constructor))
+static void constructor1(void)
+{
+	constructor_test_value = 1;
+}
+
+__attribute__((constructor))
+static void constructor2(void)
+{
+	constructor_test_value *= 2;
+}
+
 int run_startup(int min, int max)
 {
 	int test;
@@ -630,7 +648,9 @@ int run_startup(int min, int max)
 		CASE_TEST(environ_HOME);     EXPECT_PTRNZ(1, getenv("HOME")); break;
 		CASE_TEST(auxv_addr);        EXPECT_PTRGT(test_auxv != (void *)-1, test_auxv, brk); break;
 		CASE_TEST(auxv_AT_UID);      EXPECT_EQ(1, getauxval(AT_UID), getuid()); break;
-		CASE_TEST(auxv_AT_PAGESZ);   EXPECT_GE(1, getauxval(AT_PAGESZ), 4096); break;
+		CASE_TEST(constructor);      EXPECT_EQ(1, constructor_test_value, 2); break;
+		CASE_TEST(linkage_errno);    EXPECT_PTREQ(1, linkage_test_errno_addr(), &errno); break;
+		CASE_TEST(linkage_constr);   EXPECT_EQ(1, linkage_test_constructor_test_value, 6); break;
 		case __LINE__:
 			return ret; /* must be last */
 		/* note: do not set any defaults so as to permit holes above */
@@ -894,14 +914,14 @@ int run_syscall(int min, int max)
 		CASE_TEST(lseek_0);           EXPECT_SYSER(1, lseek(0, 0, SEEK_SET), -1, ESPIPE); break;
 		CASE_TEST(mkdir_root);        EXPECT_SYSER(1, mkdir("/", 0755), -1, EEXIST); break;
 		CASE_TEST(mmap_bad);          EXPECT_PTRER(1, mmap(NULL, 0, PROT_READ, MAP_PRIVATE, 0, 0), MAP_FAILED, EINVAL); break;
-		CASE_TEST(munmap_bad);        EXPECT_SYSER(1, munmap((void *)1, 0), -1, EINVAL); break;
+		CASE_TEST(munmap_bad);        EXPECT_SYSER(1, munmap(NULL, 0), -1, EINVAL); break;
 		CASE_TEST(mmap_munmap_good);  EXPECT_SYSZR(1, test_mmap_munmap()); break;
 		CASE_TEST(open_tty);          EXPECT_SYSNE(1, tmp = open("/dev/null", 0), -1); if (tmp != -1) close(tmp); break;
 		CASE_TEST(open_blah);         EXPECT_SYSER(1, tmp = open("/proc/self/blah", 0), -1, ENOENT); if (tmp != -1) close(tmp); break;
 		CASE_TEST(pipe);              EXPECT_SYSZR(1, test_pipe()); break;
 		CASE_TEST(poll_null);         EXPECT_SYSZR(1, poll(NULL, 0, 0)); break;
 		CASE_TEST(poll_stdout);       EXPECT_SYSNE(1, ({ struct pollfd fds = { 1, POLLOUT, 0}; poll(&fds, 1, 0); }), -1); break;
-		CASE_TEST(poll_fault);        EXPECT_SYSER(1, poll((void *)1, 1, 0), -1, EFAULT); break;
+		CASE_TEST(poll_fault);        EXPECT_SYSER(1, poll(NULL, 1, 0), -1, EFAULT); break;
 		CASE_TEST(prctl);             EXPECT_SYSER(1, prctl(PR_SET_NAME, (unsigned long)NULL, 0, 0, 0), -1, EFAULT); break;
 		CASE_TEST(read_badf);         EXPECT_SYSER(1, read(-1, &tmp, 1), -1, EBADF); break;
 		CASE_TEST(rmdir_blah);        EXPECT_SYSER(1, rmdir("/blah"), -1, ENOENT); break;
@@ -910,7 +930,7 @@ int run_syscall(int min, int max)
 		CASE_TEST(select_stdout);     EXPECT_SYSNE(1, ({ fd_set fds; FD_ZERO(&fds); FD_SET(1, &fds); select(2, NULL, &fds, NULL, NULL); }), -1); break;
 		CASE_TEST(select_fault);      EXPECT_SYSER(1, select(1, (void *)1, NULL, NULL, 0), -1, EFAULT); break;
 		CASE_TEST(stat_blah);         EXPECT_SYSER(1, stat("/proc/self/blah", &stat_buf), -1, ENOENT); break;
-		CASE_TEST(stat_fault);        EXPECT_SYSER(1, stat((void *)1, &stat_buf), -1, EFAULT); break;
+		CASE_TEST(stat_fault);        EXPECT_SYSER(1, stat(NULL, &stat_buf), -1, EFAULT); break;
 		CASE_TEST(stat_timestamps);   EXPECT_SYSZR(1, test_stat_timestamps()); break;
 		CASE_TEST(symlink_root);      EXPECT_SYSER(1, symlink("/", "/"), -1, EEXIST); break;
 		CASE_TEST(unlink_root);       EXPECT_SYSER(1, unlink("/"), -1, EISDIR); break;