Merge tag 'linux-kselftest-nolibc-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull nolibc updates from Shuah Khan:
 "Nolibc:
   - improved portability by removing build errors with -ENOSYS
   - added syscall6() on MIPS to support pselect6() and mmap()
   - added setvbuf(), rmdir(), pipe(), pipe2()
   - add support for ppc/ppc64
   - environ is no longer optional
   - fixed frame pointer issues at -O0
   - dropped sys_stat() in favor of sys_statx()
   - centralized _start_c() to remove lots of asm code
   - switched size_t to __SIZE_TYPE__

  Selftests:
   - improved status reporting (success/warning/failure counts, path to
     log file)
   - various code cleanups (indent, unused variables, ...)
   - more consistent test numbering
   - enabled compiler warnings
   - dropped unreliable chmod_net test
   - improved reliability (create /dev/zero & /tmp, rely less on /proc)
   - new tests (brk/sbrk/mmap/munmap)
   - improved compatibility with musl
   - new run-nolibc-test target to build and run natively
   - new run-libc-test target to build and run against native libc
   - made the cmdline parser more reliable against boolean arguments
   - dropped dependency on memfd for vfprintf() test
   - nolibc-test is no longer stripped
   - added support for extending ARCH via XARCH

  Other:
   - add Thomas as co-maintainer"

* tag 'linux-kselftest-nolibc-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (103 commits)
  tools/nolibc: avoid undesired casts in the __sysret() macro
  tools/nolibc: keep brk(), sbrk(), mmap() away from __sysret()
  tools/nolibc: silence ppc64 compile warnings
  selftests/nolibc: libc-test: use HOSTCC instead of CC
  tools/nolibc: stackprotector.h: make __stack_chk_init static
  selftests/nolibc: allow report with existing test log
  selftests/nolibc: add test support for ppc64
  selftests/nolibc: add test support for ppc64le
  selftests/nolibc: add test support for ppc
  selftests/nolibc: add XARCH and ARCH mapping support
  tools/nolibc: add support for powerpc64
  tools/nolibc: add support for powerpc
  MAINTAINERS: nolibc: add myself as co-maintainer
  selftests/nolibc: enable compiler warnings
  selftests/nolibc: don't strip nolibc-test
  selftests/nolibc: prevent out of bounds access in expect_vfprintf
  selftests/nolibc: use correct return type for read() and write()
  selftests/nolibc: avoid sign-compare warnings
  selftests/nolibc: avoid unused parameter warnings
  selftests/nolibc: make functions static if possible
  ...

1 files changed, 61 insertions, 0 deletions

diff --git a/tools/include/nolibc/crt.h b/tools/include/nolibc/crt.h
new file mode 100644
index 000000000000..a5f33fef1672
--- /dev/null
+++ b/tools/include/nolibc/crt.h
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * C Run Time support for NOLIBC
+ * Copyright (C) 2023 Zhangjin Wu <falcon@tinylab.org>
+ */
+
+#ifndef _NOLIBC_CRT_H
+#define _NOLIBC_CRT_H
+
+char **environ __attribute__((weak));
+const unsigned long *_auxv __attribute__((weak));
+
+static void __stack_chk_init(void);
+static void exit(int);
+
+void _start_c(long *sp)
+{
+	long argc;
+	char **argv;
+	char **envp;
+	const unsigned long *auxv;
+	/* silence potential warning: conflicting types for 'main' */
+	int _nolibc_main(int, char **, char **) __asm__ ("main");
+
+	/* initialize stack protector */
+	__stack_chk_init();
+
+	/*
+	 * sp  :    argc          <-- argument count, required by main()
+	 * argv:    argv[0]       <-- argument vector, required by main()
+	 *          argv[1]
+	 *          ...
+	 *          argv[argc-1]
+	 *          null
+	 * environ: environ[0]    <-- environment variables, required by main() and getenv()
+	 *          environ[1]
+	 *          ...
+	 *          null
+	 * _auxv:   _auxv[0]      <-- auxiliary vector, required by getauxval()
+	 *          _auxv[1]
+	 *          ...
+	 *          null
+	 */
+
+	/* assign argc and argv */
+	argc = *sp;
+	argv = (void *)(sp + 1);
+
+	/* find environ */
+	environ = envp = argv + argc + 1;
+
+	/* find _auxv */
+	for (auxv = (void *)envp; *auxv++;)
+		;
+	_auxv = auxv;
+
+	/* go to application */
+	exit(_nolibc_main(argc, argv, envp));
+}
+
+#endif /* _NOLIBC_CRT_H */