Merge tag 'nolibc.2022.07.27a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull nolibc updates from Paul McKenney:
 "This provides nolibc updates, perhaps most notably improved testing
  via the 'cd tools/include/nolibc; make headers' command. This should
  be considered a smoke test. More thorough testing is in the works"

* tag 'nolibc.2022.07.27a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
  tools/nolibc: add a help target to list supported targets
  tools/nolibc: make the default target build the headers
  tools/nolibc: fix the makefile to also work as "make -C tools ..."
  tools/nolibc/stdio: Add format attribute to enable printf warnings
  tools/nolibc/stdlib: Support overflow checking for older compiler versions

1 files changed, 3 insertions, 4 deletions

diff --git a/tools/include/nolibc/stdlib.h b/tools/include/nolibc/stdlib.h
index 8fd32eaf8037..92378c4b9660 100644
--- a/tools/include/nolibc/stdlib.h
+++ b/tools/include/nolibc/stdlib.h
@@ -128,10 +128,9 @@ void *malloc(size_t len)
 static __attribute__((unused))
 void *calloc(size_t size, size_t nmemb)
 {
-	void *orig;
-	size_t res = 0;
+	size_t x = size * nmemb;
 
-	if (__builtin_expect(__builtin_mul_overflow(nmemb, size, &res), 0)) {
+	if (__builtin_expect(size && ((x / size) != nmemb), 0)) {
 		SET_ERRNO(ENOMEM);
 		return NULL;
 	}
@@ -140,7 +139,7 @@ void *calloc(size_t size, size_t nmemb)
 	 * No need to zero the heap, the MAP_ANONYMOUS in malloc()
 	 * already does it.
 	 */
-	return malloc(res);
+	return malloc(x);
 }
 
 static __attribute__((unused))