From 4536da25e4c9aec0aaaeedc96f90bf46356f1dfe Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Sun, 11 Feb 2024 08:08:37 -0800 Subject: [PATCH] MIPS: Add 'memory' clobber to csum_ipv6_magic() inline assembler [ Upstream commit d55347bfe4e66dce2e1e7501e5492f4af3e315f8 ] After 'lib: checksum: Use aligned accesses for ip_fast_csum and csum_ipv6_magic tests' was applied, the test_csum_ipv6_magic unit test started failing for all mips platforms, both little and bit endian. Oddly enough, adding debug code into test_csum_ipv6_magic() made the problem disappear. The gcc manual says: "The "memory" clobber tells the compiler that the assembly code performs memory reads or writes to items other than those listed in the input and output operands (for example, accessing the memory pointed to by one of the input parameters) " This is definitely the case for csum_ipv6_magic(). Indeed, adding the 'memory' clobber fixes the problem. Cc: Charlie Jenkins Cc: Palmer Dabbelt Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Guenter Roeck Reviewed-by: Charlie Jenkins Signed-off-by: Thomas Bogendoerfer Signed-off-by: Sasha Levin --- arch/mips/include/asm/checksum.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/mips/include/asm/checksum.h b/arch/mips/include/asm/checksum.h index 5f80c28f5..6c837a256 100755 --- a/arch/mips/include/asm/checksum.h +++ b/arch/mips/include/asm/checksum.h @@ -242,7 +242,8 @@ static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr, " .set pop" : "=&r" (sum), "=&r" (tmp) : "r" (saddr), "r" (daddr), - "0" (htonl(len)), "r" (htonl(proto)), "r" (sum)); + "0" (htonl(len)), "r" (htonl(proto)), "r" (sum) + : "memory"); return csum_fold(sum); }