[PATCH 27/32] s390/string: Add KMSAN support

Ilya Leoshkevich
2023-11-15T20:37:08Z

Add KMSAN support for the s390 implementations of the string functions.
Do this similar to how it's already done for KASAN, except that the
optimized memset{16,32,64}() functions need to be disabled: it's
important for KMSAN to know that they initialized something.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
arch/s390/boot/string.c | 15 +++++++++++
arch/s390/include/asm/string.h | 49 ++++++++++++++++++++--------------
2 files changed, 44 insertions(+), 20 deletions(-)

diff --git a/arch/s390/boot/string.c b/arch/s390/boot/string.c
index faccb33b462c..6d886c84075b 100644
--- a/arch/s390/boot/string.c
+++ b/arch/s390/boot/string.c
@@ -4,8 +4,14 @@
#include <linux/errno.h>
#undef CONFIG_KASAN
#undef CONFIG_KASAN_GENERIC
+#undef CONFIG_KMSAN
#include "../lib/string.c"

+/*
+ * Duplicate some functions from the common lib/string.c
+ * instead of fully including it.
+ */
+
int strncmp(const char *cs, const char *ct, size_t count)
{
unsigned char c1, c2;
@@ -22,6 +28,15 @@ int strncmp(const char *cs, const char *ct, size_t count)
return 0;
}

+void *memset64(uint64_t *s, uint64_t v, size_t count)
+{
+ uint64_t *xs = s;
+
+ while (count--)
+ *xs++ = v;
+ return s;
+}
+
char *skip_spaces(const char *str)
{
while (isspace(*str))
diff --git a/arch/s390/include/asm/string.h b/arch/s390/include/asm/string.h
index 351685de53d2..94925024cb26 100644
--- a/arch/s390/include/asm/string.h
+++ b/arch/s390/include/asm/string.h
@@ -15,15 +15,12 @@
#define __HAVE_ARCH_MEMCPY /* gcc builtin & arch function */
#define __HAVE_ARCH_MEMMOVE /* gcc builtin & arch function */
#define __HAVE_ARCH_MEMSET /* gcc builtin & arch function */
-#define __HAVE_ARCH_MEMSET16 /* arch function */
-#define __HAVE_ARCH_MEMSET32 /* arch function */
-#define __HAVE_ARCH_MEMSET64 /* arch function */

void *memcpy(void *dest, const void *src, size_t n);
void *memset(void *s, int c, size_t n);
void *memmove(void *dest, const void *src, size_t n);

-#ifndef CONFIG_KASAN
+#if !defined(CONFIG_KASAN) && !defined(CONFIG_KMSAN)
#define __HAVE_ARCH_MEMCHR /* inline & arch function */
#define __HAVE_ARCH_MEMCMP /* arch function */
#define __HAVE_ARCH_MEMSCAN /* inline & arch function */
@@ -36,6 +33,9 @@ void *memmove(void *dest, const void *src, size_t n);
#define __HAVE_ARCH_STRNCPY /* arch function */
#define __HAVE_ARCH_STRNLEN /* inline & arch function */
#define __HAVE_ARCH_STRSTR /* arch function */
+#define __HAVE_ARCH_MEMSET16 /* arch function */
+#define __HAVE_ARCH_MEMSET32 /* arch function */
+#define __HAVE_ARCH_MEMSET64 /* arch function */

/* Prototypes for non-inlined arch strings functions. */
int memcmp(const void *s1, const void *s2, size_t n);
@@ -44,7 +44,7 @@ size_t strlcat(char *dest, const char *src, size_t n);
char *strncat(char *dest, const char *src, size_t n);
char *strncpy(char *dest, const char *src, size_t n);
char *strstr(const char *s1, const char *s2);
-#endif /* !CONFIG_KASAN */
+#endif /* !defined(CONFIG_KASAN) && !defined(CONFIG_KMSAN) */

#undef __HAVE_ARCH_STRCHR
#undef __HAVE_ARCH_STRNCHR
@@ -74,21 +74,6 @@ void *__memset16(uint16_t *s, uint16_t v, size_t count);
void *__memset32(uint32_t *s, uint32_t v, size_t count);
void *__memset64(uint64_t *s, uint64_t v, size_t count);

-static inline void *memset16(uint16_t *s, uint16_t v, size_t count)
-{
- return __memset16(s, v, count * sizeof(v));
-}
-
-static inline void *memset32(uint32_t *s, uint32_t v, size_t count)
-{
- return __memset32(s, v, count * sizeof(v));
-}
-
-static inline void *memset64(uint64_t *s, uint64_t v, size_t count)
-{
- return __memset64(s, v, count * sizeof(v));
-}
-
#if !defined(IN_ARCH_STRING_C) && (!defined(CONFIG_FORTIFY_SOURCE) || defined(__NO_FORTIFY))

#ifdef __HAVE_ARCH_MEMCHR
@@ -194,6 +179,27 @@ static inline size_t strnlen(const char * s, size_t n)
return end - s;
}
#endif
+
+#ifdef __HAVE_ARCH_MEMSET16
+static inline void *memset16(uint16_t *s, uint16_t v, size_t count)
+{
+ return __memset16(s, v, count * sizeof(v));
+}
+#endif
+
+#ifdef __HAVE_ARCH_MEMSET32
+static inline void *memset32(uint32_t *s, uint32_t v, size_t count)
+{
+ return __memset32(s, v, count * sizeof(v));
+}
+#endif
+
+#ifdef __HAVE_ARCH_MEMSET64
+static inline void *memset64(uint64_t *s, uint64_t v, size_t count)
+{
+ return __memset64(s, v, count * sizeof(v));
+}
+#endif
#else /* IN_ARCH_STRING_C */
void *memchr(const void * s, int c, size_t n);
void *memscan(void *s, int c, size_t n);
@@ -201,6 +207,9 @@ char *strcat(char *dst, const char *src);
char *strcpy(char *dst, const char *src);
size_t strlen(const char *s);
size_t strnlen(const char * s, size_t n);
+void *memset16(uint16_t *s, uint16_t v, size_t count);
+void *memset32(uint32_t *s, uint32_t v, size_t count);
+void *memset64(uint64_t *s, uint64_t v, size_t count);
#endif /* !IN_ARCH_STRING_C */

#endif /* __S390_STRING_H_ */
--
2.41.0