4.19-stable review patch. If anyone has any objections, please let me know.
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From: Guenter Roeck linux@roeck-us.net
[ 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 charlie@rivosinc.com Cc: Palmer Dabbelt palmer@rivosinc.com Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Guenter Roeck linux@roeck-us.net Reviewed-by: Charlie Jenkins charlie@rivosinc.com Signed-off-by: Thomas Bogendoerfer tsbogend@alpha.franken.de Signed-off-by: Sasha Levin sashal@kernel.org --- 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 e8161e4dfde7..4680bac894f6 100644 --- a/arch/mips/include/asm/checksum.h +++ b/arch/mips/include/asm/checksum.h @@ -276,7 +276,8 @@ 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); }