Commit 54917c90 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'nolibc-urgent.2022.10.28a' of... 

Merge tag 'nolibc-urgent.2022.10.28a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull nolibc fixes from Paul McKenney:
 "This contains a couple of fixes for string-function bugs"

* tag 'nolibc-urgent.2022.10.28a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
  tools/nolibc/string: Fix memcmp() implementation
  tools/nolibc: Fix missing strlen() definition and infinite loop with gcc-12
parents f526d6a8 b3f4f51e

tools/include/nolibc/string.h

+10 −7
Original line number Diff line number Diff line
@@ -19,9 +19,9 @@ static __attribute__((unused)) 
int memcmp(const void *s1, const void *s2, size_t n)

{

	size_t ofs = 0;

	char c1 = 0;

	int c1 = 0;



	while (ofs < n && !(c1 = ((char *)s1)[ofs] - ((char *)s2)[ofs])) {

	while (ofs < n && !(c1 = ((unsigned char *)s1)[ofs] - ((unsigned char *)s2)[ofs])) {

		ofs++;

	}

	return c1;
@@ -125,14 +125,18 @@ char *strcpy(char *dst, const char *src) 
}



/* this function is only used with arguments that are not constants or when

 * it's not known because optimizations are disabled.

 * it's not known because optimizations are disabled. Note that gcc 12

 * recognizes an strlen() pattern and replaces it with a jump to strlen(),

 * thus itself, hence the asm() statement below that's meant to disable this

 * confusing practice.

 */

static __attribute__((unused))

size_t nolibc_strlen(const char *str)

size_t strlen(const char *str)

{

	size_t len;



	for (len = 0; str[len]; len++);

	for (len = 0; str[len]; len++)

		asm("");

	return len;

}
@@ -140,13 +144,12 @@ size_t nolibc_strlen(const char *str) 
 * the two branches, then will rely on an external definition of strlen().

 */

#if defined(__OPTIMIZE__)

#define nolibc_strlen(x) strlen(x)

#define strlen(str) ({                          \

	__builtin_constant_p((str)) ?           \

		__builtin_strlen((str)) :       \

		nolibc_strlen((str));           \

})

#else

#define strlen(str) nolibc_strlen((str))

#endif



static __attribute__((unused))