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

[Ilya Leoshkevich]

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@xxxxxxxxxxxxx>
---
 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