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s390/lib: add missing memory barriers to string inline assemblies 

We have a couple of inline assemblies like memchr() and strlen() that
read from memory, but tell the compiler only they need the addresses
of the strings they access.
This allows the compiler to omit the initialization of such strings
and therefore generate broken code. Add the missing memory barrier to
all string related inline assemblies to fix this potential issue. It
looks like the compiler currently does not generate broken code due to
these bugs.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Heiko Carstens 2016-12-13 09:50:30 +01:00 committed by Martin Schwidefsky
parent 259acc5c25
commit 7a71fd1c59
2 changed files with 10 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
arch/s390/include/asm/string.h
View File

@ -62,7 +62,7 @@ static inline void *memchr(const void * s, int c, size_t n)
" jl 1f\n"
" la %0,0\n"
"1:"
: "+a" (ret), "+&a" (s) : "d" (r0) : "cc");
: "+a" (ret), "+&a" (s) : "d" (r0) : "cc", "memory");
return (void *) ret;
}
@ -74,7 +74,7 @@ static inline void *memscan(void *s, int c, size_t n)
asm volatile(
"0: srst %0,%1\n"
" jo 0b\n"
: "+a" (ret), "+&a" (s) : "d" (r0) : "cc");
: "+a" (ret), "+&a" (s) : "d" (r0) : "cc", "memory");
return (void *) ret;
}
@ -115,7 +115,7 @@ static inline size_t strlen(const char *s)
asm volatile(
"0: srst %0,%1\n"
" jo 0b"
: "+d" (r0), "+a" (tmp) : : "cc");
: "+d" (r0), "+a" (tmp) : : "cc", "memory");
return r0 - (unsigned long) s;
}
@ -128,7 +128,7 @@ static inline size_t strnlen(const char * s, size_t n)
asm volatile(
"0: srst %0,%1\n"
" jo 0b"
: "+a" (end), "+a" (tmp) : "d" (r0) : "cc");
: "+a" (end), "+a" (tmp) : "d" (r0) : "cc", "memory");
return end - s;
}
#else /* IN_ARCH_STRING_C */

12
arch/s390/lib/string.c
View File

@ -20,7 +20,7 @@ static inline char *__strend(const char *s)
asm volatile ("0: srst %0,%1\n"
" jo 0b"
: "+d" (r0), "+a" (s) : : "cc" );
: "+d" (r0), "+a" (s) : : "cc", "memory");
return (char *) r0;
}
@ -31,7 +31,7 @@ static inline char *__strnend(const char *s, size_t n)
asm volatile ("0: srst %0,%1\n"
" jo 0b"
: "+d" (p), "+a" (s) : "d" (r0) : "cc" );
: "+d" (p), "+a" (s) : "d" (r0) : "cc", "memory");
return (char *) p;
}
@ -213,7 +213,7 @@ int strcmp(const char *cs, const char *ct)
" sr %0,%1\n"
"1:"
: "+d" (ret), "+d" (r0), "+a" (cs), "+a" (ct)
: : "cc" );
: : "cc", "memory");
return ret;
}
EXPORT_SYMBOL(strcmp);
@ -250,7 +250,7 @@ static inline int clcle(const char *s1, unsigned long l1,
" ipm %0\n"
" srl %0,28"
: "=&d" (cc), "+a" (r2), "+a" (r3),
"+a" (r4), "+a" (r5) : : "cc");
"+a" (r4), "+a" (r5) : : "cc", "memory");
return cc;
}
@ -298,7 +298,7 @@ void *memchr(const void *s, int c, size_t n)
" jl 1f\n"
" la %0,0\n"
"1:"
: "+a" (ret), "+&a" (s) : "d" (r0) : "cc" );
: "+a" (ret), "+&a" (s) : "d" (r0) : "cc", "memory");
return (void *) ret;
}
EXPORT_SYMBOL(memchr);
@ -336,7 +336,7 @@ void *memscan(void *s, int c, size_t n)
asm volatile ("0: srst %0,%1\n"
" jo 0b\n"
: "+a" (ret), "+&a" (s) : "d" (r0) : "cc" );
: "+a" (ret), "+&a" (s) : "d" (r0) : "cc", "memory");
return (void *) ret;
}
EXPORT_SYMBOL(memscan);