Merge tag 'nolibc-20260206-for-7.0-1' of git://git.kernel.org/pub/scm/linux/kernel/git/nolibc/linux-nolibc

Pull nolibc updates from Thomas Weißschuh:

 - All time-related functionality uses 64-bit timestamps for
   y2038 compatibility

 - fread() and fskeek() support

 - ptrace() support

 - Addition of libc-test to the regular kselftests

 - Smaller cleanups and fixes to the code and build system

* tag 'nolibc-20260206-for-7.0-1' of git://git.kernel.org/pub/scm/linux/kernel/git/nolibc/linux-nolibc: (25 commits)
  tools/nolibc: Add a simple test for writing to a FILE and reading it back
  tools/nolibc: Add fseek() to stdio.h
  tools/nolibc: Add fread() to stdio.h
  selftests/nolibc: also test libc-test through regular selftest framework
  selftests/nolibc: scope custom flags to the nolibc-test target
  selftests/nolibc: try to read from stdin in readv_zero test
  selftests/nolibc: always build sparc32 tests with -mcpu=v8
  tools/nolibc: align sys_vfork() with sys_fork()
  selftests/nolibc: drop NOLIBC_SYSROOT=0 logic
  selftests/nolibc: add static assertions around time types handling
  tools/nolibc: add __nolibc_static_assert()
  tools/nolibc: add compiler version detection macros
  tools/nolibc: remove time conversions
  selftests/nolibc: test compatibility of nolibc and kernel time types
  tools/nolibc: always use 64-bit time types
  tools/nolibc: use custom structs timespec and timeval
  tools/nolibc/select: avoid libgcc 64-bit multiplications
  tools/nolibc/gettimeofday: avoid libgcc 64-bit divisions
  tools/nolibc: prefer explicit 64-bit time-related system calls
  tools/nolibc/time: drop invocation of gettimeofday system call
  ...

3 files changed, 93 insertions, 15 deletions

diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index 40f5c2908dda..0370489d938b 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/tools/testing/selftests/nolibc/Makefile
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 
-TEST_GEN_PROGS := nolibc-test
+TEST_GEN_PROGS := nolibc-test libc-test
 
 include ../lib.mk
 include $(top_srcdir)/scripts/Makefile.compiler
@@ -9,16 +9,16 @@ cc-option = $(call __cc-option, $(CC),,$(1),$(2))
 
 include Makefile.include
 
-CFLAGS = -nostdlib -nostdinc -static \
+$(OUTPUT)/nolibc-test: CFLAGS = -nostdlib -nostdinc -static \
 	 -isystem $(top_srcdir)/tools/include/nolibc -isystem $(top_srcdir)/usr/include \
 	 $(CFLAGS_NOLIBC_TEST)
-
-ifeq ($(LLVM),)
-LDLIBS := -lgcc
-endif
-
+$(OUTPUT)/nolibc-test: LDLIBS = $(if $(LLVM),,-lgcc)
 $(OUTPUT)/nolibc-test: nolibc-test.c nolibc-test-linkage.c | headers
 
+$(OUTPUT)/libc-test: nolibc-test.c nolibc-test-linkage.c
+	$(call msg,CC,,$@)
+	$(Q)$(LINK.c) $^ -o $@
+
 help:
 	@echo "For the custom nolibc testsuite use '$(MAKE) -f Makefile.nolibc'; available targets:"
 	@$(MAKE) -f Makefile.nolibc help
diff --git a/tools/testing/selftests/nolibc/Makefile.nolibc b/tools/testing/selftests/nolibc/Makefile.nolibc
index f9d43cbdc894..f5704193038f 100644
--- a/tools/testing/selftests/nolibc/Makefile.nolibc
+++ b/tools/testing/selftests/nolibc/Makefile.nolibc
@@ -226,7 +226,7 @@ CFLAGS_mipsn32be = -EB -mabi=n32 -march=mips64r6
 CFLAGS_mips64le = -EL -mabi=64 -march=mips64r6
 CFLAGS_mips64be = -EB -mabi=64 -march=mips64r2
 CFLAGS_loongarch = $(if $(LLVM),-fuse-ld=lld)
-CFLAGS_sparc32 = $(call cc-option,-m32)
+CFLAGS_sparc32 = $(call cc-option,-m32) -mcpu=v8
 CFLAGS_sh4 = -ml -m4
 ifeq ($(origin XARCH),command line)
 CFLAGS_XARCH = $(CFLAGS_$(XARCH))
@@ -302,15 +302,9 @@ sysroot/$(ARCH)/include:
 	$(Q)$(MAKE) -C $(srctree)/tools/include/nolibc ARCH=$(ARCH) OUTPUT=$(CURDIR)/sysroot/ headers_standalone headers_check
 	$(Q)mv sysroot/sysroot sysroot/$(ARCH)
 
-ifneq ($(NOLIBC_SYSROOT),0)
 nolibc-test: nolibc-test.c nolibc-test-linkage.c sysroot/$(ARCH)/include
 	$(QUIET_CC)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ \
 	  -nostdlib -nostdinc -static -Isysroot/$(ARCH)/include nolibc-test.c nolibc-test-linkage.c $(LIBGCC)
-else
-nolibc-test: nolibc-test.c nolibc-test-linkage.c
-	$(QUIET_CC)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ \
-	  -nostdlib -static -include $(srctree)/tools/include/nolibc/nolibc.h nolibc-test.c nolibc-test-linkage.c $(LIBGCC)
-endif
 
 libc-test: nolibc-test.c nolibc-test-linkage.c
 	$(QUIET_CC)$(HOSTCC) -o $@ nolibc-test.c nolibc-test-linkage.c
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index 3c5a226dad3a..1b9d3b2e2491 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -17,6 +17,7 @@
 #include <sys/mman.h>
 #include <sys/mount.h>
 #include <sys/prctl.h>
+#include <sys/ptrace.h>
 #include <sys/random.h>
 #include <sys/reboot.h>
 #include <sys/resource.h>
@@ -877,6 +878,58 @@ int test_file_stream(void)
 	return 0;
 }
 
+int test_file_stream_wsr(void)
+{
+	const char dataout[] = "foo";
+	const size_t datasz = sizeof(dataout);
+	char datain[datasz];
+	int fd, r;
+	FILE *f;
+
+	fd = open("/tmp", O_TMPFILE | O_RDWR, 0644);
+	if (fd == -1)
+		return -1;
+
+	f = fdopen(fd, "w+");
+	if (!f)
+		return -1;
+
+	errno = 0;
+	r = fwrite(dataout, 1, datasz, f);
+	if (r != datasz)
+		return -1;
+
+	/* Attempt to read from the file without rewinding,
+	 * we should read 0 items.
+	 */
+	r = fread(datain, 1, datasz, f);
+	if (r)
+		return -1;
+
+	/* Rewind the file to the start */
+	r = fseek(f, 0, SEEK_SET);
+	if (r)
+		return -1;
+
+	/* Attempt to read back more than was written to
+	 * make sure we handle short reads properly.
+	 * fread() should return the number of complete items.
+	 */
+	r = fread(datain, 1, datasz + 1, f);
+	if (r != datasz)
+		return -1;
+
+	/* Data we read should match the data we just wrote */
+	if (memcmp(datain, dataout, datasz) != 0)
+		return -1;
+
+	r = fclose(f);
+	if (r)
+		return -1;
+
+	return 0;
+}
+
 enum fork_type {
 	FORK_STANDARD,
 	FORK_VFORK,
@@ -1351,6 +1404,7 @@ int run_syscall(int min, int max)
 		CASE_TEST(fchdir_stdin);      EXPECT_SYSER(1, fchdir(STDIN_FILENO), -1, ENOTDIR); break;
 		CASE_TEST(fchdir_badfd);      EXPECT_SYSER(1, fchdir(-1), -1, EBADF); break;
 		CASE_TEST(file_stream);       EXPECT_SYSZR(1, test_file_stream()); break;
+		CASE_TEST(file_stream_wsr);   EXPECT_SYSZR(1, test_file_stream_wsr()); break;
 		CASE_TEST(fork);              EXPECT_SYSZR(1, test_fork(FORK_STANDARD)); break;
 		CASE_TEST(getdents64_root);   EXPECT_SYSNE(1, test_getdents64("/"), -1); break;
 		CASE_TEST(getdents64_null);   EXPECT_SYSER(1, test_getdents64("/dev/null"), -1, ENOTDIR); break;
@@ -1403,9 +1457,10 @@ int run_syscall(int min, int max)
 		CASE_TEST(write_badf);        EXPECT_SYSER(1, write(-1, &tmp, 1), -1, EBADF); break;
 		CASE_TEST(write_zero);        EXPECT_SYSZR(1, write(1, &tmp, 0)); break;
 		CASE_TEST(readv_badf);        EXPECT_SYSER(1, readv(-1, &iov_one, 1), -1, EBADF); break;
-		CASE_TEST(readv_zero);        EXPECT_SYSZR(1, readv(1, NULL, 0)); break;
+		CASE_TEST(readv_zero);        EXPECT_SYSZR(1, readv(0, NULL, 0)); break;
 		CASE_TEST(writev_badf);       EXPECT_SYSER(1, writev(-1, &iov_one, 1), -1, EBADF); break;
 		CASE_TEST(writev_zero);       EXPECT_SYSZR(1, writev(1, NULL, 0)); break;
+		CASE_TEST(ptrace);            EXPECT_SYSER(1, ptrace(PTRACE_CONT, getpid(), NULL, NULL), -1, ESRCH); break;
 		CASE_TEST(syscall_noargs);    EXPECT_SYSEQ(1, syscall(__NR_getpid), getpid()); break;
 		CASE_TEST(syscall_args);      EXPECT_SYSER(1, syscall(__NR_statx, 0, NULL, 0, 0, NULL), -1, EFAULT); break;
 		CASE_TEST(namespace);         EXPECT_SYSZR(euid0 && proc, test_namespace()); break;
@@ -1428,6 +1483,34 @@ int test_difftime(void)
 	return 0;
 }
 
+int test_time_types(void)
+{
+#ifdef NOLIBC
+	struct __kernel_timespec kts;
+	struct timespec ts;
+
+	if (!__builtin_types_compatible_p(time_t, __kernel_time64_t))
+		return 1;
+
+	if (sizeof(ts) != sizeof(kts))
+		return 1;
+
+	if (!__builtin_types_compatible_p(__typeof__(ts.tv_sec), __typeof__(kts.tv_sec)))
+		return 1;
+
+	if (!__builtin_types_compatible_p(__typeof__(ts.tv_nsec), __typeof__(kts.tv_nsec)))
+		return 1;
+
+	if (offsetof(__typeof__(ts), tv_sec) != offsetof(__typeof__(kts), tv_sec))
+		return 1;
+
+	if (offsetof(__typeof__(ts), tv_nsec) != offsetof(__typeof__(kts), tv_nsec))
+		return 1;
+#endif /* NOLIBC */
+
+	return 0;
+}
+
 int run_stdlib(int min, int max)
 {
 	int test;
@@ -1553,6 +1636,7 @@ int run_stdlib(int min, int max)
 		CASE_TEST(difftime);                EXPECT_ZR(1, test_difftime()); break;
 		CASE_TEST(memchr_foobar6_o);        EXPECT_STREQ(1, memchr("foobar", 'o', 6), "oobar"); break;
 		CASE_TEST(memchr_foobar3_b);        EXPECT_STRZR(1, memchr("foobar", 'b', 3)); break;
+		CASE_TEST(time_types);              EXPECT_ZR(is_nolibc, test_time_types()); break;
 
 		case __LINE__:
 			return ret; /* must be last */