MIPS: LLVMLinux: Fix an 'inline asm input/output type mismatch' error.

Replace incorrect matching constraint that caused the error with an alternative
that still has the required constraints on the inline assembly.

This is the error message reported by clang:
arch/mips/include/asm/checksum.h:285:27: error: unsupported inline asm: input with type '__be32' (aka 'unsigned int') matching output with type 'unsigned short'
          "0" (htonl(len)), "1" (htonl(proto)), "r" (sum));
                                 ^~~~~~~~~~~~

The changed code can be compiled successfully by both gcc and clang.

Signed-off-by: Daniel Sanders <daniel.sanders@imgtec.com>
Signed-off-by: Toma Tabacu <toma.tabacu@imgtec.com>
Suggested-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/9313/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/include/asm/checksum.h b/arch/mips/include/asm/checksum.h
index 5c585c5c1c3e3fe3ee6bacdfd8ce0f59be82e27e..3ceacde5eb6e4fd3a7b05906ce3fe153b57c8e5c 100644 (file)
--- a/arch/mips/include/asm/checksum.h
+++ b/arch/mips/include/asm/checksum.h
@@ -218,6 +218,8 @@ static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
                                          __u32 len, unsigned short proto,
                                          __wsum sum)
 {
+       __wsum tmp;
+
        __asm__(
        "       .set    push            # csum_ipv6_magic\n"
        "       .set    noreorder       \n"
@@ -270,9 +272,9 @@ static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 
        "       addu    %0, $1          # Add final carry\n"
        "       .set    pop"
-       : "=r" (sum), "=r" (proto)
+       : "=&r" (sum), "=&r" (tmp)
        : "r" (saddr), "r" (daddr),
-         "0" (htonl(len)), "1" (htonl(proto)), "r" (sum));
+         "0" (htonl(len)), "r" (htonl(proto)), "r" (sum));
 
        return csum_fold(sum);
 }