4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nathan Chancellor natechancellor@gmail.com
commit b0c091ae04f6746f541b9be91809e1f4f43e9a65 upstream.
Clang errors out when building this macro:
lib/mpi/generic_mpih-mul1.c:37:24: error: invalid use of a cast in a inline asm context requiring an l-value: remove the cast or build with -fheinous-gnu-extensions umul_ppmm(prod_high, prod_low, s1_ptr[j], s2_limb); ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ lib/mpi/longlong.h:652:20: note: expanded from macro 'umul_ppmm' : "=l" ((USItype)(w0)), \ ~~~~~~~~~~^~~ lib/mpi/generic_mpih-mul1.c:37:3: error: invalid output constraint '=h' in asm umul_ppmm(prod_high, prod_low, s1_ptr[j], s2_limb); ^ lib/mpi/longlong.h:653:7: note: expanded from macro 'umul_ppmm' "=h" ((USItype)(w1)) \ ^ 2 errors generated.
The C version that is used for GCC 4.4 and up works well with clang; however, it is not currently being used because Clang masks itself as GCC 4.2.1 for compatibility reasons. As Nick points out, we require GCC 4.6 and newer in the kernel so we can eliminate all of the versioning checks and just use the C version of umul_ppmm for all supported compilers.
Link: https://github.com/ClangBuiltLinux/linux/issues/605 Suggested-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Nathan Chancellor natechancellor@gmail.com Reviewed-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- lib/mpi/longlong.h | 36 +----------------------------------- 1 file changed, 1 insertion(+), 35 deletions(-)
--- a/lib/mpi/longlong.h +++ b/lib/mpi/longlong.h @@ -639,30 +639,12 @@ do { \ ************** MIPS ***************** ***************************************/ #if defined(__mips__) && W_TYPE_SIZE == 32 -#if (__GNUC__ >= 5) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 4) #define umul_ppmm(w1, w0, u, v) \ do { \ UDItype __ll = (UDItype)(u) * (v); \ w1 = __ll >> 32; \ w0 = __ll; \ } while (0) -#elif __GNUC__ > 2 || __GNUC_MINOR__ >= 7 -#define umul_ppmm(w1, w0, u, v) \ - __asm__ ("multu %2,%3" \ - : "=l" ((USItype)(w0)), \ - "=h" ((USItype)(w1)) \ - : "d" ((USItype)(u)), \ - "d" ((USItype)(v))) -#else -#define umul_ppmm(w1, w0, u, v) \ - __asm__ ("multu %2,%3\n" \ - "mflo %0\n" \ - "mfhi %1" \ - : "=d" ((USItype)(w0)), \ - "=d" ((USItype)(w1)) \ - : "d" ((USItype)(u)), \ - "d" ((USItype)(v))) -#endif #define UMUL_TIME 10 #define UDIV_TIME 100 #endif /* __mips__ */ @@ -687,7 +669,7 @@ do { \ : "d" ((UDItype)(u)), \ "d" ((UDItype)(v))); \ } while (0) -#elif (__GNUC__ >= 5) || (__GNUC__ >= 4 && __GNUC_MINOR__ >= 4) +#else #define umul_ppmm(w1, w0, u, v) \ do { \ typedef unsigned int __ll_UTItype __attribute__((mode(TI))); \ @@ -695,22 +677,6 @@ do { \ w1 = __ll >> 64; \ w0 = __ll; \ } while (0) -#elif __GNUC__ > 2 || __GNUC_MINOR__ >= 7 -#define umul_ppmm(w1, w0, u, v) \ - __asm__ ("dmultu %2,%3" \ - : "=l" ((UDItype)(w0)), \ - "=h" ((UDItype)(w1)) \ - : "d" ((UDItype)(u)), \ - "d" ((UDItype)(v))) -#else -#define umul_ppmm(w1, w0, u, v) \ - __asm__ ("dmultu %2,%3\n" \ - "mflo %0\n" \ - "mfhi %1" \ - : "=d" ((UDItype)(w0)), \ - "=d" ((UDItype)(w1)) \ - : "d" ((UDItype)(u)), \ - "d" ((UDItype)(v))) #endif #define UMUL_TIME 20 #define UDIV_TIME 140